Patent Application
20070106065
A compact disc containing the file 50111.051002 TAT-001 sequence listing.txt, 210 kB, created on Jan. 30, 2006, has been submitted in duplicate and is hereby incorporated by reference.
The present inventors have discovered that increased expression of TAT-001 protein in human patients is associated with colon tumors as compared to adjacent normal tissue. Thus, the present inventors have discovered that TAT-001 is associated with abnormal development and growth, and can be used as a target for the identification of potential anti-cancer compounds, including antibodies for use in immunotherapy.
In 2000, worldwide, there were more than 10 million cases of cancer identified, and over 6 million cancer-related deaths. 23% of all deaths in the United States in 2000 were cancer-related. Colorectal cancer makes up a significant proportion of that statistic, as colorectal cancer is the third most common cancer, and the second most commonly fatal cancer in the United States (ranking third in men behind lung and prostate cancer respectively, and third in women behind lung and breast cancer).
Colon cancer rates have stabilized in recent years, but 2003 U.S. estimates indicate that colorectal cancer cases still comprise an estimated 11% of all male cancer cases and 11% of all female cancer cases (74,283 men; 72,468 women; 146,751 total), with an estimated 40% mortality rate. Currently, 5.6% of Americans will have colorectal cancer at some point in their life (1 in 17 men, 1 in 18 women), and 70-80% of colorectal cancers occur in people of average risk. Hospital time is still significant for non-fatal cases. There is also a strong potential for an upward trend in these U.S. statistics given the ongoing rise in American obesity and the known links between obesity and increased colon cancer risk (an estimated 40% increased risk of incidence for men, as well as a doubled risk and increased mortality for women).
Treatment for colon cancer remains unsatisfactory in terms of mortality, recurrence after treatment, and invasiveness. Surgery is the most common treatment for colon cancer. Despite the majority of patients having their entire tumor removed by surgery, as many as 40% will develop a recurrence. 40-50% of patients have metastatic disease at the time of diagnosis, with a poor prognosis and an average survival measured only in months. Patients and their physicians choosing non-surgical treatments as follow-up, in place of, or in conjunction with, surgery must also weigh the benefits of therapy versus the side effects of the treatment: even successful current treatments, although benefiting the patient overall, can have a profound negative impact on a survivor's health and quality of life.
Some tumors also become refractory to treatments leading to recurrent or metastatic disease, which is often incurable. Indeed, cancers can have diverse etiologies with resultant differing patterns of protein expression, which can dictate response to treatment. The identification of common suitable targets or antigens for therapy of colon cancer has become increasingly important—both as initial therapies and as therapies for cancers that have become refractory to other treatments.
Diagnosis of colon cancer itself is problematic. When diagnosed early at a localized stage, 5 year survivability is 90%, yet only 37% of colon cancers are diagnosed while still localized. New predictive non-invasive markers are needed. Current blood-based biomarkers that can be used in the diagnosis and monitoring of disease, such as the carcinoembryonic antigen (CEA), are not fully reliable. The identification of new proteins overexpressed in colon cancer might provide further opportunities for such diagnostics, as well as screening methods to determine the most appropriate treatment.
Thus, both the diagnosis and treatment of colon cancer remains problematic, and there is a need in the art for improved methods of detecting and treating colorectal cancers. Immunotherapy and the use of tumor-related antigens for diagnostics and treatment have previously provided new approaches, but there remains a scarcity of credible antigen targets suitable for treating colon cancer.
The inventors have identified TAT-001 protein from two peptides unique to its sequence (peptide #1 and peptide #2) using highly accurate mass spectrometric and bioinformatic methods on highly enriched and pure plasma membrane samples derived from viable epithelial cells of fresh human colon cancer tumor tissue and matched adjacent normal tissue. The inventors have discovered that Tumor Antigen Target-001 (TAT-001) is frequently overexpressed at the cell surface in colon cancers as compared to adjacent normal tissue. These results robustly indicate the viability of TAT-001 protein as a potential target for immunotherapy based on its localization to the plasma membrane and its reproducibly elevated expression level in colon cancer tissue relative to normal tissue in a percentage of patients comparable with that of other current cancer immunotherapies. The present invention relates to compositions of and methods of use for the TAT-001 protein and its encoding nucleic acids. The invention also features methods for identifying TAT-001 interactors and modulators for use as diagnostic tools or therapeutic tools for identifying and targeting of cancer cells, and for regulating TAT-001 finction, such as in the treatment of disease. The invention further relates to methods and compositions useful in the prophylaxis, diagnosis, treatment and management of various cancers that express TAT-001, in particular colon cancer. Such methods include the production, compositions, and uses of antibodies, vaccines, antigen presenting cells that express TAT-001, T cells specific for cells expressing TAT-001, and immunotherapy.
Accordingly, the present invention provides a substantially pure TAT-001 polypeptide or a fragment thereof and nucleic acid sequences useful in carrying out the methods of the invention. Isolated polypeptides of the invention (TAT-001 polypeptides): a) comprise or consist of the amino acid sequence of SEQ ID NO: 1; b) comprise or consist of the amino acid sequence of SEQ ID NO: 3; c) comprise or consist of the amino acid sequence of SEQ ID NO: 1 and the amino acid sequence of SEQ ID NO: 3; d) comprise or consist of the amino acid sequence of SEQ ID NO: 5; e) are derivatives having one or more amino acid substitutions, modifications, deletions or insertions relative to the amino acid sequence of SEQ ID NO: 5 and have at least 40% homology, preferably 50%, 60%, 70%, 80%, 90%, 95% or more, over the length of the sequence; f) are fragments of a polypeptide having the amino acid sequence of SEQ ID NO: 5, which are at least four amino acids long and have at least 40% homology over the length of the fragment; g) comprise additional amino acid sequence for coupling to a coupling agent; h) comprise a terminal cysteine as an additional amino acid sequence for coupling to a coupling agent; or i) comprise additional amino acid sequences facilitating purification, wherein such additional sequences comprises a myc, FLAG, HIS, HA, GST, affinity or epitope tag. In desirable embodiments, the TAT-001 polypeptide is from a mammal, preferably a human.
Isolated nucleic acid molecules of the invention (TAT-001 nucleic acids): a) comprise or consist of the DNA sequence of SEQ ID NO: 2 or its RNA equivalent; b) comprise or consist of the DNA sequence of SEQ ID NO: 4 or its RNA equivalent; c) comprise or consist of the DNA sequence of SEQ ID NO: 6 or its RNA equivalent; d) have a sequence which is complementary to the sequences of (a), (b), and/or (c); e) have a sequence which codes for a polypeptide as defmed in (a) to (i) of the previous paragraph; f) comprise or consist of a gDNA sequence per (e); g) comprise or consist of a promoter associated with (f); h) have a sequence which consists essentially of any of those of (a), (b), (c), (d), (e), (f) and (g); i) have a sequence which shows substantial identity with any of those of (a), (b), (c), (d), (e), (f), (g) and (h); j) are fragments of (a), (b), (c), (d), (e), (f), (g), (h) or (i), which are at least ten nucleotides in length; k) are sequences per (a), (b), (c), (d), (e), (f), (g), (h), (i) and/or (j) which also comprise transcriptional and/or translational regulatory elements; or l) are sequences per (a), (b), (c), (d), (e), (f), (g), (h), (i), (j) and/or (k) which are part of a vector, plasmid, virus-based vector, or artificial chromosome. The invention also provides for host cells that contain one or more of the nucleic acids, and methods for expressing and purifying the polypeptides of the invention therefrom.
The invention further provides compositions for inducing an immune response, which include an isolated polypeptide as described above and a physiologically acceptable carrier. Additional compositions for inducing an immune response are also provided, which include an isolated polypeptide of TAT-001 as described above and a non-specific immune response enhancer, e.g., an adjuvant. Further, compositions for inducing an immune response, including a nucleic acid encoding the isolated polypeptide, as described above, and a physiologically acceptable carrier are provided.
The invention also features a method of inducing an immune response to a TAT-001 polypeptide that includes providing a TAT-001 polypeptide as described above that comprises at least one T cell antigen or at least one B cell antigen or at least one antigen presenting cell antigen; and, contacting the antigen with an immune system T cell or B cell or antigen presenting cell respectively, whereby an immune response is induced. The polypeptide may be accompanied by an adjuvant. The invention also features a method inducing an immune response in a subject by administering a composition including a TAT-001 polypeptide to the subject.
The invention also provides for antibodies, finctionally-active fragments, derivatives or analogues thereof (herein, TAT-001 antibodies), which specifically bind a TAT-001 polypeptide (e.g., polypeptides including the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 8, SEQ ID NO: 12, SEQ ID NO: 15, SEQ ID NO: 18, SEQ ID NO: 21, SEQ ID NO: 25, SEQ ID NO: 28, or SEQ ID NO: 32), where the antibodies may be monoclonal, polyclonal, single-chain, chimeric, humanized, fully human, bispecific, or any combination thereof. Preferred antibody fragments include a Fab fragment, a F(ab)'2 fragment, or an Fv fragment. The antibodies can also be conjugated to a therapeutic moiety, detectable label, second antibody or a fragment thereof, a cytotoxic agent, or cytokine. The invention also provides isolated cells, hybridomas, non-human transgenic animals, or plants that produce the antibodies or fragments thereof.
The invention also provides for TAT-001 antibody-related proteins and nucleic acids. These include proteins comprising or consisting of the antigen-binding region of an antibody or fragment thereof, wherein the protein may be conjugated to a therapeutic moiety, detectable label, second antibody or a fragment thereof, a cytotoxic agent or cytokine. The antibody-related proteins also include TAT-001-binding proteins that are derivatives having one or more amino acid substitutions, modifications, deletions or insertions relative to a TAT-001 antibody or fragment thereof and which retain at least 10%, preferably 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or more, of the binding activity of the antibody, wherein TAT-001-binding protein may be conjugated to a therapeutic moiety, detectable label, second antibody or a fragment thereof, a cytotoxic agent or cytokine. The invention also features isolated nucleic acid molecules which: a) have a sequence which codes for a TAT-001 antibody or fragment thereof, a TAT-001-binding protein, or a protein comprising or consisting of the antigen-binding region of an antibody or fragment thereof; b) comprise or consist of a gDNA sequence per (a); c) have a sequence which consists essentially of any of those of (a) or (b); d) have a sequence which shows substantial identity with any of those of (a), (b), and (c); e) are a fragment of (a), (b), (c), or (d), which is at least ten nucleotides in length; f) are a sequence per (a), (b), (c), (d), and/or (e) which also comprises transcriptional and/or translational regulatory elements; or g) are a sequence per (a), (b), (c), (d), (e), and/or (f) which is part of a vector, plasmid, virus-based vector, or artificial chromosome. The invention also provides for host cells that contain one or more of the nucleic acids, and methods for expressing and purifying the polypeptides of the invention therefrom.
Methods for selecting a TAT-001 binding molecule, such as an antibody, antibody-related protein, or small molecule are also provided. In one embodiment, the invention features a method for selecting an antibody that binds with high binding affinity to a mammalian TAT-001 that includes the steps of: (a) providing a peptide comprising a TAT-001 polypeptide, optionally coupled to an immunogenic carrier; and (b) contacting the TAT-001 polypeptide with a TAT-001 binding molecule, wherein the TAT-001 binding molecule is an antibody, under conditions that allow for complex formation between the TAT-001 polypeptide and the TAT-001 binding molecule, thereby selecting a TAT-001 binding molecule that binds with high binding affinity to a mammalian TAT-001.
The invention also provides for assays for detecting the presence of TAT-001 polypeptide or a TAT-001 nucleic acid in a biological sample comprising steps of: contacting the sample with a TAT-001 binding molecule (e.g., specifically binds to a TAT-001 polypeptide or TAT-001 nucleic acid); and, detecting the binding of TAT-001 polypeptide or TAT-001 nucleic acid in the sample thereto. The invention additionally provides for a diagnostic kit comprising a capture reagent specific for a TAT-001 polypeptide, reagents, and instructions for use. Such methods and kits can also be used to detect a mutant TAT-001 polypeptide or nucleic acid in a sample.
The invention also provides for diagnostic methods including a method of screening for and/or diagnosis of a cellular proliferative disease in a subject, and/or monitoring the effectiveness of therapy, which includes the step of detecting and/or quantifying in a biological sample obtained from the subject: (i) a TAT-001 polypeptide or (ii) a TAT-001 nucleic acid molecule. The polypeptide or nucleic acid may be compared to a reference range or a control sample, preferably one that was previously determined. The step of detecting may include: a) contacting the sample with a capture reagent that is specific for a TAT-001 polypeptide and b) detecting whether binding has occurred between the capture reagent and the polypeptide in the sample. Step (b) may further comprise detecting the captured polypeptide using a directly or indirectly labeled detection reagent. The capture reagent in these methods of screening and/or diagnosis may be immobilized on a solid phase and/or the TAT-001 polypeptide may be detected and/or quantified using an antibody that recognizes a TAT-001 polypeptide. The diagnostic methods can also be used to detect a mutant TAT-001 polypeptide or nucleic acid that is associated with a cellular proliferative disease. For nucleic acids, the methods can include analyzing the sequence or the restriction fragment length (e.g., by restriction fragment length polymorphism analysis) of the nucleic acids of the test subject and comparing it to the sequence or the restriction fragment length of a TAT-001 nucleic acid molecule. Detection of a mutation can indicate that the test subject has an increased likelihood of developing a cellular proliferative disease (e.g., cancer).
The invention further provides a method of screening for anti-cellular proliferative disease agents that interact with a TAT-001 polypeptide that includes: contacting the polypeptide with a candidate agent and determining whether or not the candidate agent interacts with the polypeptide. Also provided are comparative methods for identifying a candidate compound for the treatment of cellular proliferative diseases that includes: measuring the binding of a TAT-001 binding molecule to a TAT-001 polypeptide in the presence of a test compound and measuring the binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound; where the level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the presence of the test compound that is altered (e.g., increased or decreased) from the level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound is an indication that the test compound is a potential therapeutic compound for the treatment of a cellular proliferative disease.
The invention further provides a method for identifying a compound for diagnosing a cellular proliferative disease. The method includes: measuring the binding of a TAT-001 binding molecule to a TAT-001 polypeptide in the presence of a test compound and measuring the binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound; wherein a level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the presence of the test compound that is altered (e.g., increased or decreased) from the level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound is an indication that the test compound is a potential compound for diagnosing a cellular proliferative disease. The determination of interaction between the candidate agent and TAT-001 polypeptide can include quantitatively or qualitatively detecting binding of the candidate agent and the polypeptide.
Additionally, the invention provides a method of screening for anti-cellular proliferative disease agents that modulate: the expression or activity of a TAT-001 polypeptide and/or the expression of a TAT-001 nucleic acid molecule. The method includes comparing the expression or activity of the TAT-001 polypeptide and/or the expression of the TAT-001 nucleic acid molecule, in the presence of a candidate agent with the respective expression or activity in the absence of the candidate agent or in the presence of a control agent; and determining whether the candidate agent causes a change (e.g., increase or decrease) in the expression or activity of the TAT-001 polypeptide and/or the expression of the TAT-001 nucleic acid molecule. The expression or activity level of the TAT-001 polypeptide and/or the expression level of the nucleic acid molecule may be compared with a reference range, preferably a predetermined reference range, or a control sample. This method may additionally include selecting an agent that modulates the expression or activity of the TAT-001 polypeptide and/or the expression of the TAT-001 nucleic acid molecule for further testing, or for therapeutic or prophylactic use as an anti-cellular proliferative disease agent. The invention also provides agents, identified by these methods, which modulate the expression or activity of the TAT-001 polypeptide or TAT-001 nucleic acid molecule.
The invention also provides for the manufacture of medicaments for the treatment of a cellular proliferative disease, including the use of a TAT-001 polypeptide a TAT-001 nucleic acid molecule, or a TAT-001 antibody in the manufacture of a medicament for the treatment of a cellular proliferative disease, such as colon cancer. The use of vaccines in the manufacture of a medicament for the treatment of a cellular proliferative disease, and the use of an agent which interacts with, or modulates the expression or activity of a TAT-001 polypeptide or the expression of a TAT-001 nucleic acid in the manufacture of a medicament for the treatment of a cellular proliferative disease are also provided.
The invention also provides a kit for the analysis of a TAT-001 nucleic acid molecule that includes a TAT-001 nucleic acid molecule probe for analyzing the nucleic acid molecule of a test subject. The invention also provides a kit for the analysis of a TAT-001 polypeptide that includes an antibody or a TAT-001 binding protein for analyzing the TAT-001 polypeptide of a test subject.
Pharmaceutical compositions provided by the invention include substances that modulate the status of cells that expresses TAT-001. Such pharmaceutical compositions may include a TAT-001 polypeptide and a physiologically acceptable carrier. They may also comprise a TAT-001 antibody or fragment thereof, a TAT-001-binding protein, or a protein comprising or consisting of the antigen-binding region of a TAT-001 antibody or fragment thereof that specifically binds to a TAT-001 polypeptide, and a physiologically acceptable carrier. Pharmaceutical compositions of the invention provided also include pharmaceutical compositions comprising any one or more of the following: a TAT-001 polynucleotide and a physiologically acceptable carrier; a ribozyme capable of cleaving a TAT-001 polynucleotide and a physiologically acceptable carrier; and a polynucleotide that encodes a TAT-001 antibody or fragment thereof, a TAT-001-binding protein, or a protein comprising or consisting of the antigen-binding region of a TAT-001 antibody or fragment thereof that specifically binds to a TAT-001 polypeptide and a physiologically acceptable carrier.
The invention provides treatments for a cellular proliferative disease that include a therapeutically effective amount of at least one of the pharmaceutical compositions or medicaments of the invention. The invention also provides a method of delivering a cytotoxic agent to a cell that expresses TAT-001. The method includes conjugating the cytotoxic agent to TAT-001 antibody or fragment thereof that specifically binds to a TAT-001 epitope and exposing the cell to the antibody-agent conjugate.
In preferred embodiments of any of the above methods, the cellular proliferative disease is cancer. The preferred cancer is colon cancer.
The invention also provides methods for preventing or ameliorating the effect of a TAT-001 deficiency that includes administering to a subject having a TAT-001 deficiency, a therapeutically effective amount of a compound (e.g., a finctional TAT-001 polypeptide) to prevent or ameliorate the TAT-001 deficiency. The invention further provides methods for preventing or ameliorating the effect of a TAT-001 excess that includes administering to a subject having a TAT-001 excess, a therapeutically effective amount of a compound to prevent or ameliorate the TAT-001 deficiency.
The compositions and methods of the invention are useful for the identification, manufacture, and modification of anti-cellular proliferative disease compounds and anti-cancer compounds, cellular proliferative disease diagnostics, cancer diagnostics, cellular proliferative disease treatments and cancer treatments, as well as other utilities. The compositions and methods of the invention provide the following advantages in addition to others not enumerated here: TAT-001 is a novel target for diagnostic, prognostic, theranostic, and preventative methods for cellular proliferative diseases, such as cancer, in particular colon cancer. Furthermore, TAT-001 antibodies, TAT-001 antibody-related proteins, TAT-001 interacting proteins, and anti-cancer compounds described herein provide tools for identifying additional potential diagnostics, therapies, and compounds for treatment of cellular proliferative diseases.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
All differential abundance (dA) ratios and corresponding differential intensity (dI) ratios were obtained. The figure shows a plot of all such pairs where the mean differential abundance and standard deviations are plotted. The black line is the best fit linear regression. dA is clearly predicted from dI.
Definitions Unless defmed otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art. Unless otherwise indicated, such as through context, as used herein, the following terms are intended to have the following meanings in interpreting the present invention.
“Active against” in the context of compounds, agents, or compositions having anti-cancer activity indicates that the compound exerts an effect through interaction with or modulation of a particular target or targets in a manner that is deleterious to the in vitro and/or in vivo growth, proliferation, and/or metastasis of a cancer cell or cells. In particular, a compound active against a gene exerts an action on a target, which affects an expression product of that gene. This does not necessarily mean that the compound acts directly on the expression product of the gene, but instead indicates that the compound affects the expression product in a deleterious manner. Thus, the direct target of the compound may be upstream of the expression or finction of a target gene in a cancer cell and be considered active against the target gene. For example, the direct target may be a component of the target gene's genomic locus, which can be modulated to reduce transcription of the gene, resulting in a lower level of expression. Likewise, the compound may affect the level of translation of the polypeptide expression product, or may act on a downstream component of a biochemical pathway in which the expression product of the gene has a major biological role. Consequently, such a compound can be said to be active against the gene, against the gene product, or against the related component either upstream or downstream of that gene or expression product. While the term “active against” encompasses a broad range of potential activities, it also implies some degree of specificity of target. Therefore, for example, a general protease is not necessarily considered “active against” a particular gene which produces a polypeptide product. In contrast, a compound that inhibits a particular enzyme is active against that enzyme and against the gene, which codes for that enzyme.
“Active agent,” “pharmacologically active agent,” “agent,” and “drug” are used interchangeably herein to refer to a compound that induces a desired phenotypic, pharmacological, or physiological effect or a desired effect on an activity. The terms also encompass pharmaceutically acceptable, pharmacologically active derivatives of those active agents specifically mentioned herein, including, but not limited to, salts, esters, amides, prodrugs, active metabolites, analogs, and the like. When the terms “active agent,” “pharmacologically active agent”, and “drug” are used, then, it is to be understood that the applicant intends to include the active agent per se as well as pharmaceutically acceptable, pharmacologically active salts, esters, amides, prodrugs, metabolites, analogs, etc. Anti-cancer agents are active agents. Candidate agents are potential active agents. “Agent” may also be used in the context of “binding agent,” referring to a compound, for example a ligand, small molecule, or antibody, that exhibits specific binding with another compound, but that does not necessarily have phenotypic, pharmacological or physiological effects, or effects on an activity. TAT-001 binding agents may be identified by any of the screening methods that permit detection of specific binding provided herein, for example identified modulators of TAT-001 activity or expression that bind TAT-001 nucleic acids and/or TAT-001 polypeptides can be considered TAT-001 binding agents, or TAT-001 binding molecules.
“Activity” comprises one or more measurable properties of a protein, capable of acting or affecting a change on itself, or another molecule, or on a cell, tissue, organ, or organism. Although “activity” may often be taken to imply active finction, it is meant to encompass measurable passive functions as well (e.g., maintaining structural conformation of a particular protein complex), preferably those that relate to cancer or disease phenotypes or mechanisms, and most preferably those of TAT-001, that regulate TAT-001, or that are regulated by TAT-001. Some examples, not intended to be limiting, include catalytic enzymatic activity, translocation, binding, immunological activity (including specifically immunogenicity—see for example the assays described under the definition of “antigen” below), or participation in a biochemical, or phenotypic pathway. Those skilled in the art should be able to produce or identify appropriate assays for the activity to be assessed. The activity may be carried out indirectly, such as through functioning in a pathway, and encompasses activities that require co-factors or presence in a protein complex. A percentage activity can be determined by comparison to a control in an assay for the particular activity being examined. Methods for such comparisons are commonly known in the art. For example, the percent kinase activity of a derivative of TAT-001 can be assessed by comparison to the level of activity of underivatized TAT-001 under appropriately similar conditions in a kinase assay, should a kinase assay be an appropriate activity to measure for TAT-001. Activities may be self-directed, such as auto-catalytic activity. Some assays may require the use of TAT-001 nucleic acids, such as for expression, or producing transgenic cell lines, or specific mutant, variant, or derivative forms of TAT-001.
Some activity assays that may be useful in carrying out the methods of the invention, including identifying finctions of TAT-001 polypeptides and TAT-001 nucleic acids, not intended to be limiting, include cell proliferation assays, such as mitotic index (see, for example, Oka et al. (1994) Arch Pathol Lab Med. 118: 506-509; Weidner et al. (1994) Hum Pathol. 25: 337-342), thymidine incorporation assays (see, for example, Rodriguez et al. (1993) Am J Obstet Gynecol. 168: 228-232; Sugihara et al. (1992) Int J Cell Cloning 10: 344-351; Hayward et al. (1992) Int J Cell Cloning 10: 182-189; Sondak et al. (1988) Int J Cell Cloning 6: 378-391), bromodeoxyuridine (BrdU) incorporation assays (see, for example, Limas (1993) J Pathol. 171: 39-47), MIB-1 staining (see, for example, Spyratos et al. (2002) Cancer 94: 2151-2159), or anti-PCNA (proliferating cell nuclear antigen) staining (see, for example, Hall et al. (1990) J Pathol. 162: 285-294; Kurki et al. (1988) J Immunol Methods 109: 49-59; Kubben et al. (1994) Gut 35: 530-535; and the in situ hybridization method of Kohler et al. (2004 Dec. 23; Epub ahead of print) Histochem Cell Biol.); growth suppression assays, such as assays of susceptibility to arrest (see, for example, Guan et al. (1994) Genes Dev. 8: 2939-2952; Gulliya et al. (1994) Cancer 74: 1725-1732), and drug resistance assays (for example, Vybrant® Multidrug Resistance Assay Kit, catalog # V13180 from Molecular Probes, Eugene, Oreg.); apoptosis assays, such as DAPI staining, TUNEL assay (e.g., Fluorescein FragEL DNA Fragmentation Detection Kit (Oncogene Research Products, Cat.# QIA39)+Tetramethyl-rhodamine-5-dUTP (Roche, Cat. #1534 378)) or APO-BrdU™ TUNEL Assay Kit, catalog #A23210 from Molecular Probes, Eugene, Ore.) or an assay based on Protease Activity (such as caspases) (for example, EnzChek® Caspase-3 Assay Kit #1, catalog # E13183 from Molecular Probes, Eugene, Oreg.); angiogenesis assays (see, for example, Storgard et al. (2004) Methods Mol Biol. 294: 123-136; Baronikova et al. (2004) Planta Med. 70: 887-892; Hasan et al. (2004) Angiogenesis 7: 1-16; Friis et al. (2003) APMIS. 111: 658-668); cell migration assays (for example, Yarrow et al. (2004) BMC Biotechnol. 4: 21; Berens and Beaudry (2004) Methods Mol Med. 88: 219-24; Heit and Kubes (2003) Sci STKE. 2003 (170): PL5); cell adhesion assays (for example, those using enzyme substrates, such as the Vybrant® Cell Adhesion Assay Kit, catalog # V13181 from Molecular Probes, Eugene, Oreg.); assays of ability to grow on soft agar or colony formation assays (see, for example, Freshney (1994) Culture of Animal Cells a Manual of Basic Technique, 3rd ed., Wiley-Liss, New York); assays for changes in contact inhibition or density limitation of growth (see, for example, Freshney (1994), supra); assays of changes in growth factor or serum dependence (see, e.g., Temin (1966) J Natl Cancer Insti. 37: 167-175; Eagle et al. (1970) J Exp Med. 131: 836-879; Freshney (1994) Culture of Animal Cells a Manual of Basic Technique, 3rd ed., Wiley-Liss, New York); assays of changes in the level of tumor specific markers (for example, Mazumdar et al. (1999) Trop Gastroenterol. 20: 107-110; Rosandic et al. (1999) Acta Med Austriaca 26: 89-92; Clarke et al. (2003) Int J Oncol. 22: 425-30; Nowak et al. (2003) Eur J Gastroenterol Hepatol. 15: 75-80; Sarkar et al. (2002) Int J Pharm. 238: 1-9; Streckfus et al. (2001) Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 91: 174-179; Werther et al. (2000) Eur J Surg Oncol. 26: 657-662; Halberg et al. (1995) In Vivo. 9: 311-314; Varela et al. (1993) Oncology 50: 430-435; Turner et al. (1990) Eur J Gynaecol Oncol. 11: 421 -427; Masood (1994) J Cell Biochem Suppl. 19: 28-35; Vogel and Kalthoff (2001) Virchows Arch. 439: 109-117); assays of changes in invasiveness into Matrigel (see, for example, Freshney (1994), supra); assays of changes in cell cycle pattern (for example, as determined by flow cytometry, or mRNA or protein expression in synchronized cells (see, for example, Li et al. (1994) Oncogene 9: 2261-2268); assays of changes in tumor growth in vivo, such as in transgenic mice (for example, Huh et al. (2005) Oncogene 24: 790-800; White et al. (2004) Cancer Cell 6: 159-170; Finkle et al. (2004) Clin Cancer Res. 10: 2499-2511; Williams et al. (2004) J Biol Chem. 279: 24745-24756; Cuadros et al. (2003) Cancer Res. 63: 5895-5901; Quaglino et al. (2002) Immunol Lett. 80: 75-79; Shibata et al. (2001) Cancer Gene Ther. 8: 23-35; Nielsen et al. (2000) Cancer Res. 60: 7066-7074), or in xenografts (for example, in immune suppressed mice, such as SCID mice; see Houghton et al. (1989) Invest New Drugs. 7: 59-69; Rygaard and Spang-Thomsen (1997) Breast Cancer Res Treat. 46: 303-312; van Weerden and Romijn (2000) Prostate 2000 43: 263-271; Azzoli et al. (2002) Semin Oncol. 29: 59-65; Sliwkowski et al. (1999) Semin Oncol. 26: 60-70); binding assays; known cancer diagnostics; etc. Such assays can be used to screen for anti-cancer agents, including identification of TAT-001 nucleic acids or TAT-001 polypeptides which are capable of altering or inhibiting abnormal proliferation and transformation in host cells, and activators, inhibitors, and modulators of TAT-001 nucleic acids and TAT-001 polypeptides. Such activators, inhibitors, and modulators of TAT-001 can then be used to modulate TAT-001 expression in tumor cells or abnormal proliferative cells. Identified TAT-001 nucleic acids or TAT-001 polypeptides which are capable of inhibiting abnormal proliferation and transformation in host cells can be used in a number of diagnostic or therapeutic methods, e.g., in gene therapy to inhibit abnormal cellular proliferation and transformation.
“Administering” refers to delivering a foreign substance or a precursor thereof to one or more cells, such as a tissue or organism, for example a mouse or a human. Means of administering the foreign substance vary depending on the cell's environment. For example, a foreign substance can be delivered to a cell in culture by adding the substance to the cell culture media. Delivery of a foreign substance to a cell in a body organ or tissue might require more sophisticated means of delivery, including, but not limited to, implantation, direct injection, injection into the bloodstream or lymphatic system, encapsulated or unencapsulated oral delivery, foodstuffs, solutions, gels, ointments, and the like.
“Affinity” refers to strength of binding between substances, and/or methods based on binding. A high binding affinity is generally desired between an antibody and its antigen, or, for example, a specific and high affinity compound can generally be used to more readily purify a specific protein from a mixture than a low affinity compound. A lower affinity compound might be used, for example, if broader specificity is desired, such as allowing several members of a particular protein family to be isolated. By “high binding affinity” is meant binding with an affinity constant of less than 1 micromolar, preferably, less than 100 nanomolar, and more preferably, less than 10 nanomolar. Most preferably, for TAT-001 binding molecules, especially TAT-001 antibodies, high binding affinity means a specific and/or selective TAT-001 binding molecule with greater affinity for a TAT-001 than previously demonstrated for a particular class of binding molecule (e.g., small molecule, antibody, antibody fragment, cyclic peptide, ligand, etc.) Binding and affinity assays known in the art may be used to determine such relative affinity or screen for high affinity binders.
“Affinity tag” refers to a sequence added to the coding information of an expressed protein to provide a convenient site that can be recognized by a capture reagent. The resultant protein is often referred to as a fusion protein. Affinity tags may be encoded at any point in the coding sequence, but are typically placed so as to produce an N- or C-terminal “tag.” More than one tag, possibly of more than one type, may be encoded in a coding sequence. Affinmity tags may often also be used as epitope tags, but affinity tag is often used to refer to a tag commonly used in a process that involves a capture reagent other than antibodies, such as nickel beads used with a HIS-tag. Typical examples of affinity tags are the “HIS” and “GST” tags.
“Altered” or “changed” refers to a detectable change or difference from a reasonably comparable state, profile, measurement, or the like. One skilled in the art should be able to determine a reasonable measurable change. Such changes may be all or none. They may be incremental and need not be linear. They may be by orders of magnitude. A change may be an increase or decrease by 1%, 5%, 10%, 20%,30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, 100%, or more, or any value in between 0% and 100%.
“Analogue” refers to a molecule, or substructure or fragment thereof, having a same or similar activity or finction as another molecule (“analogous activity”). An analogue can often complement a “knockout” of the gene or protein to which it is analogous in an assay, such as a phenotypic assay. Analogous activity should generally be at least within 1 to 2 orders of magnitude for the gene or gene product to be considered an analogue, but more specific acceptable ranges may be noted and defined by context herein. Two kinases may be broadly considered to have the same activity with regard to enzymatic finction, although they may or may not be considered analogous with regard to a particular substrate.
“Antibody” refers to an immunoglobulin protein (or proteins such as in the case of a polyclonal antibody) whether naturally or synthetically produced, which is capable of binding an antigen, whether the antigen is that which caused the antibody's production, one which a recombinant antibody was designed to bind, or to which the antibody's binding was identified, such as through in vitro binding assays. The term may be used to encompass the antibody, antibody fragments, a polypeptide substantially encoded by at least one immunoglobulin gene or fragments of at least one immunoglobulin gene, which can participate in specific binding with the antigen, and/or naturally-occurring forms, conjugates, and derivatives, thereof. An antibody of the invention recognizes a TAT-001 polypeptide. Preferably, an antibody of the invention specifically binds to a TAT-001 polypeptide. The immunoglobulin molecules of the invention can be of any class (e.g., IgG, IgE, IgM, IgD, and IgA) or subclass of immunoglobulin molecule. The term also covers any protein having a binding domain that is homologous to or derived from an immunoglobulin binding domain, such as a CDR region or a cyclized peptide based on a CDR amino acid sequence, though terms such as “antigen-binding region of an antibody” may also be used to encompass CDR regions and the like. An antibody can be from a mammal, non-mammal (e.g., birds, chickens, fish, etc.), or partially or fully synthetic. A “mammal” is a member of the class Mammalia. Examples of mammals include, without limitation, humans, primates, chimpanzees, rodents, mice, rats, rabbits, sheep, and cows.
Derivatives within the scope of the term include antibodies that have been modified in sequence, but remain capable of specific binding to a target molecule, including interspecies, chimeric, and humanized antibodies. When they are naturally produced, antibodies are secreted into the bloodstream to seek out and bind foreign agents or antigens for destruction. An antibody may be monoclonal or polyclonal, and present in a variety of media including, but not limited to, serum or supernatant, or in purified form. As used herein, antibodies can be produced by any known technique, including harvest from cell culture of native B lymphocytes, hybridomas, recombinant expression systems, by phage display, or the like. Methods of production of polyclonal antibodies are known to those of skill in the art. In brief, an immunogen, preferably a purified protein or biomolecule, is mixed with an adjuvant and animals are immunized. When appropriately high titers of antibody to the immunogen are obtained, blood is collected from the animal and antiserum is prepared. Monoclonal antibodies may be obtained by various techniques familiar to those skilled in the art. Briefly, spleen cells from an animal immunized with a desired antigen are immortalized, commonly by fusion with a myeloma cell (see Kohler and Milstein (1976) Eur. J. Immunol. 6: 511-519). Alternative methods of immortalization include transformation with Epstein Barr Virus, oncogenes, or retroviruses, or other methods well known in the art. Colonies arising from single immortalized cells are screened for production of antibodies of the desired specificity and affinity for the antigen, and yield of the monoclonal antibodies produced by such cells may be enhanced by various techniques, including injection into the peritoneal cavity of a vertebrate host.
“Antibody fragment” or “antibody protein fragment” refers to a portion of an antibody (e.g., Fv) capable of binding to an antigen. Fragments within the scope of the term as used herein include those produced by digestion with various peptidases, such as Fab, Fab′ and F(ab)′2 fragments, those produced by chemical dissociation, by chemical cleavage, and by recombinant techniques, so long as the fragment remains capable of specific binding to a target molecule. Typical recombinant fragments, as are produced, e.g., by phage display, include single chain Fab and scFv (“single chain variable region”) fragments. Derivatives within the scope of the term include those that have been modified in sequence, but remain capable of specific binding to a target molecule, including interspecies, chimeric, and humanized antibodies.
“Anti-cancer agent” refers to a compound, agent, or composition active against one or more cancers or cellular proliferative diseases, and/or preventative of one or more cancers or cellular proliferative diseases. An anti-cancer agent is an active agent.
“Antigen” refers to a substance that is or will be introduced or injected into a vertebrate animal such as a mammal or poultry; or presented by antigen presentation machinery; or brought into contact with a T cell, B cell, or antigen presenting cell to induce an immune response, particularly the formation of specific antibodies that can combine or bind with the antigen. An antigen need not be immunogenic. Antigens that can induce an immune response are often referred to as immunogenic. Antigens, such as peptides, may be tested to determine immunogenicity by an appropriate assay, as may be known in the art. For example, an assay for immunogenicity is the production of antibodies that recognize the antigen, such as in immunoprecipitation or immunoblotting, in response to antigen challenge. Another example is assaying for T cell stimulation by an antigen, such as a TAT-001 polypeptide: T cells may be stimulated with a polypeptide, polynucleotide encoding a polypeptide and/or an antigen presenting cell (APC) that expresses such a polypeptide. Such stimulation is performed under conditions and for a time sufficient to permit the generation of T cells that are specific for the polypeptide of interest. Preferably, an antigen, such as a TAT-001 polypeptide or TAT-001 polynucleotide of the invention, is present within a delivery vehicle, such as a microsphere, to facilitate the generation of specific T cells. T cells are considered to be activated by a polypeptide if the T cells specifically proliferate, secrete cytokines or kill target cells coated with the antigen polypeptide or expressing a gene encoding the polypeptide. T cell activation may be evaluated using any of a variety of standard techniques. For example, within a chromium release assay or proliferation assay, a stimulation index of more than two-fold increase in lysis and/or proliferation, compared to negative controls, indicates T cell specificity. Such assays may be performed, for example, as described in Chen et al. (1994) Cancer Res. 54: 1065-1070. Alternatively, detection of the proliferation of T cells may be accomplished by a variety of known techniques. For example, T cell proliferation can be detected by measuring an increased rate of DNA synthesis (e.g., by pulse-labeling cultures of T cells with tritiated thymidine and measuring the amount of tritiated thymidine incorporated into DNA). Contact with an immunogenic polypeptide (100 ng/ml-100 μg/ml, preferably 200 ng/ml-25 μg/ml) for 3-7 days typically results in at least a two-fold increase in proliferation of the T cells. Contact as described above for 2-3 hours should result in activation of the T cells, as measured using standard cytokine assays in which a two-fold increase in the level of cytokine release (e.g., TNF or IFN-γ) is indicative of T cell activation (see Coligan et al. (1998) Current Protocols in Immunology, vol. 1, Wiley Interscience (Greene 1998)). T cells that have been activated in response to an immunogenic polypeptide, polynucleotide or polypeptide-expressing APC may be CD4+ and/or CD8+). Immunogenicity may also be predicted using various softwares.
Antigens that are taken up and presented by an antigen presenting cell may be referred to herein as antigen presenting cell antigens. Antigens capable of activating T cells or B cells may be referred to herein as T cell antigens and B cell antigens, respectively. Generally, an adjuvant may accompany an antigen to provide an additional degree of immunogenicity. The portions of the antigen that make contact with the antibody are denominated “epitopes.” Antigens can be derived from a broad range of sources and can include, for example, viruses, proteins, nucleic acids, organic compounds, and the like. Encompassed within this term herein are haptens, small antigenic determinants capable of inducing an immune response only when coupled to a carrier. Haptens bind to antibodies but by themselves cannot induce an antibody response.
“Antigen presentation” refers to the process by which certain cells in the body (antigen presenting cells) express antigen on their cell surfaces in a form recognizable by lymphocytes.
“Antigen presentation machinery” refers to the proteins, biomolecules, and co-factors involved in the proteolysis, transport and delivery to the cell surface, and presentation of previously foreign substances as antigens on the cell surface by MHC1 and/or MHC2.
“Artificial chromosome” refers to a DNA construct that comprises a replication origin, telomere, and centromere, for replication, propagation to and maintainance in progeny human cells. In addition, they may be constructed to carry other sequences for analysis or gene transfer.
“Binding” refers to a non-covalent or a covalent interaction, preferably non-covalent, that holds two molecules together. For example, two such molecules could be an enzyme and an inhibitor of that enzyme. Another example would be an enzyme and its substrate. A third example would be an antibody and an antigen. Non-covalent interactions include, but are not limited to, hydrogen bonding, ionic interactions among charged groups, van der Waals interactions, and hydrophobic interactions among non-polar groups. One or more of these interactions can mediate the binding of two molecules to each other. Binding may exhibit discriminatory properties such as specificity or selectivity.
As used herein, “biological sample” (or “sample”) refers to any solid or fluid sample obtained from, excreted by, or secreted by any living organism, including single-celled micro-organisms (such as bacteria and yeasts) and multicellular organisms (such as plants and animals, for instance a vertebrate or a mammal, and in particular a healthy or apparently healthy human subject (e.g., a reference sample), a human patient affected by a condition or disease to be diagnosed or investigated), and those subjected to environmental or treatment conditions. A biological sample may be a biological fluid obtained from any location (such as whole blood, blood plasma, blood serum, urine, bile, cerebrospinal fluid, aqueous or vitreous humor, or any bodily secretion), an exudate (such as fluid obtained from an abscess or any other site of infection or inflammation), or fluid obtained from a joint (such as a normal joint or a joint affected by disease such as rheumatoid arthritis). Alternatively, a biological sample can be obtained from any organ or tissue (including a biopsy or autopsy specimen) or may comprise cells (whether primary cells or cultured cells) or medium conditioned by any cell, tissue, or organ. If desired, the biological sample is subjected to preliminary processing, including separation techniques. For example, cells or tissues can be extracted and subjected to subcellular fractionation for separate analysis of biomolecules in distinct subcellular fractions, e.g., proteins or drugs found in different parts of the cell. A sample may be analyzed as subsets of the sample, e.g., bands from a gel. “Sample” may also be more broadly used to encompass recombinant, synthetic, and in vitro generated compounds or collections of compounds, and/or their combination with or presence in biological samples, for example, a protein complex produced and self-assembled in reticulocyte lysate by in vitro translation (IVT, e.g., Product # L4540, Flexi® Rabbit Reticulocyte Lysate System, Promega, Madison, Wis.). Such samples may be useful as controls or in providing a desired set of experimental conditions, such as for a method of screening.
“Candidate agent” refers to a potential active agent, such as a potential anti-cancer agent. “Candidate active agent” or “candidate anti-cancer agent” may also be used herein.
A “capture reagent” is a substance that can bind to a target molecule. Generally, such binding is selective and/or specific. The affinity of such reagents may vary. Preferably the affinity is high enough to reasonably meet the aims of the method they are used to address. More preferably they are of high binding affinity. However, a collection of low affinity binders can be combined to provide a high affinity equivalent (high avidity). High avidity capture reagents are also preferable. Such reagents are often used for their selective and/or specific properties in separation or purification methods. In some cases less selective reagents may be preferable, such as those that could effectively bind and deplete a family of proteins via a similar or common epitope, but in other cases highly selective or specific reagents capable of distinguishing even small differences between similar proteins may be preferred. An example of a capture reagent is nickel, such as may be present in a column to purify histidine-tagged proteins from a bacterial cell lysate. Immunoaffinity reagents are capture reagents composed at least in part of naturally occurring or engineered antibodies, antibody fragments including CDR peptides, and the like. Immunoaffinity reagents may recognize one or more antigens or epitopes. TAT-001 or fragments thereof may be used in the methods of the invention as capture reagents, and are preferred embodiments of such. Other preferred capture reagents include TAT-001 binding molecules and fragments thereof, of which more preferred are TAT-001 antibodies and fragments thereof.
“cDNA” means complementary deoxyribonucleic acid.
“Cellular proliferative disease” is intended to refer to any condition characterized by the undesired propagation of cells. Included are conditions such as neoplasms, cancers, myeloproliferative disorders, and solid tumors. Some non-limiting examples of cancers that may be treated by the compositions and methods of the invention include: Cardiac: sarcoma (angiosarcoma, fibrosarcoma, rhabdomyosarcoma, liposarcoma), myxoma, rhabdomyoma, fibroma, lipoma and teratoma; Lung: bronchogenic carcinoma (squamous cell, undifferentiated small cell, undifferentiated large cell, adenocarcinoma), alveolar (bronchiolar) carcinoma, bronchial adenoma, sarcoma, lymphoma, chondromatous hamartoma, mesothelioma; Gastrointestinal: esophagus (squamous cell carcinoma, adenocarcinoma, leiomyosarcoma, lymphoma), stomach (carcinoma, lymphoma, leiomyosarcoma), pancreas (ductal adenocarcinoma, insulinoma, glucagonoma, gastrinoma, carcinoid tumors, vipoma), small bowel (adenocarcinoma, lymphoma, carcinoid tumors, Karposi's sarcoma, leiomyoma, hemangioma, lipoma, neurofibroma, fibroma), large bowel (adenocarcinoma, tubular adenoma, villous adenoma, hamartoma, leiomyoma); Genitourinary tract: kidney (adenocarcinoma, Wilm's tumor [nephroblastoma], lymphoma, leukemia), bladder and urethra (squamous cell carcinoma, transitional cell carcinoma, adenocarcinoma), prostate (adenocarcinoma, sarcoma), testis (seminoma, teratoma, embryonal carcinoma, teratocarcinoma, choriocarcinoma, sarcoma, interstitial cell carcinoma, fibroma, fibroadenoma, adenomatoid tumors, lipoma); Liver: hepatoma (hepatocellular carcinoma), cholangiocarcinoma, hepatoblastom, angiosarcoma, hepatocellular adenoma, hemangioma; Bone: osteogenic sarcoma (osteosarcoma), fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma, Ewing's sarcoma, malignant lymphoma (reticulum cell sarcoma), multiple myeloma, malignant giant cell tumor chordoma, osteochronfroma (osteocartilaginous exostoses), chondroblastoma, chondromyxofibroma, osteoid osteoma and giant cell tumors; Nervous system: skull (osteoma, hemangioma, granuloma, xanthoma, osteitis deformans), meninges (meningioma, meningiosarcoma, gliomatosis), brain (astrocytoma, medulloblastoma, glioma, ependymoma, gerninoma [pinealoma], glioblastoma multiform, oligodendroglioma, schwannoma, retinoblastoma, congenital tumors), spinal cord neurofibroma, meningioma, glioma, sarcoma); Gynecological: uterus (endometrial carcinoma), cervix (cervical carcinoma, pre-tumor cervical dysplasia), ovaries (ovarian carcinoma [serous cystadenocarcinoma, mucinous cystadenocarcinoma, unclassified carcinoma], granulosa-thecal cell tumors, Sertoli-Leydig cell tumors, dysgerminoma, malignant teratoma), vulva (squamous cell carcinoma, intraepithelial carcinoma, adenocarcinoma, fibrosarcoma, melanoma), vagina (clear cell carcinoma, squamous cell carcinoma, botryoid sarcoma [embryonal rhabdomyosarcoma], fallopian tubes (carcinoma); Hematologic: blood (myeloid leukemia [acute and chronic], acute lymphoblastic leukemia, chronic lymphocytic leukemia, myeloproliferative diseases, multiple myeloma, myelodysplastic syndrome), Hodgkin's disease, non-Hodgkin's lymphoma [malignant lymphoma]; Skin: malignant melanoma, basal cell carcinoma, squamous cell carcinoma, Karposi's sarcoma, lipoma, angioma, dermatofibroma, keloids; and Adrenal glands: neuroblastoma. Preferably, treatment of such cancers by the methods and compositions of the invention is in vivo in the patient of origin, however, it may occur in vitro such as treatment of derived cell lines or treatment of ex-plants or xenografts. “Cellular proliferative diseases” also include non-cancerous conditions such as benign melanomas, benign chondroma, benign prostatic hyperplasia, psoriasis, moles, dysplastic nevi, dysplasia, hyperplasias, and other cellular growths occurring within the epidermal layers, as well as angiogenesis. The term is also intended to encompass diseases that can be treated or maintained by slowing, arresting, or decreasing host cell proliferation, for example, viruses whose replication is slowed or inhibited by slowing or inhibiting host cell entry into S phase, the cell cycle phase during which host cell DNA replication occurs.
“Codes for” or “encodes” refer to a DNA or RNA sequence capable of being wholly or partially replicated, transcribed, transcribed and translated, or translated to give a particular product. Hence, DNA may be transcribed into an RNA that can be translated into a given protein and thus “encodes” the protein (likewise it encodes the RNA).
As used herein, “colon tissue”, “colorectal tissue”, “colorectal cancer”, and “colon cancer” refer to tissue or cancer, respectively, of the colon itself, as well as the tissue adjacent to and/or within the strata underlying the colon and supporting structures such as the mesentery. The colon (also called the bowel, or large intestine) itself is taken in this context as representing the cecum, appendix, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon, rectosigmoid segment, rectum, and anal canal: in other words the part of the intestine from the cecum to the rectum. The tissue or cancer may be from a mammal and is preferably from a human, although monkeys, apes, cats, dogs, cows, horses and rabbits are within the scope of the present invention.
As used herein, “colon cancer” or “colorectal cancer” preferably refers to cancers of the colon and/or rectum, but may include any disease or other disorder of the gastrointestinal tract of a human or other mammal. Gastrointestinal neoplastic disorders include, for example, familial juvenile polyposis, gastrointestinal stromal tumors, familial adenomatous polyposis, hereditary non-polyposis colorectal cancer, colon cancer, rectal cancer, anal cancer, upper gastrointestinal cancer, gastrointestinal sarcomas, Peutz-Jeghers Syndrome, Cowden's syndrome, dysplasia, hyperplasia, neoplasia, and metastatses. Colon tumors may be of any stage or grade. Preferably the term may be used to refer collectively to any dysplasia, hyperplasia, neoplasia, or metastasis in which TAT-001 nucleic acids or TAT-001 polypeptides are expressed above normal levels as may be determined, for example, by comparision to adjacent healthy tissue.
“Complementary sequence” refers to nucleic acid sequence of bases that can form a double-stranded structure by matching base pairs. For example, the complementary sequence to 5′-C-A-T-G-3′ (where each letter stands for one of the bases in DNA) is 3′-G-T-A-C-5′. A pair of complementary sequences may be RNA-RNA, RNA-DNA, DNA-RNA, or DNA-DNA. “Percent complementary” (“% complementary”) may be used to refer to the percent sequence identity to a complementary sequence of the particular type nucleic acid desired (e.g., an RNA complement to a DNA sequence, or a DNA complement thereto), generally to delimit the acceptable number of mismatches in base pairing. Such mismatches may be contiguous or discontiguous.
“Control” generally refers to an experiment or sample, condition, organism, etc., which can be used as a standard of comparison in judging, checking, or verifying experimental results. For example, an experiment in which samples are treated as in a parallel experiment except for omission of the procedure or agent under test may act as a control experiment for the parallel experiment, thereby indicating which effects may be correlated with the use of the procedure or agent. Preferably a control minimizes the number of possible differences between itself and the thing (experiment, organism, etc.) it parallels to help eliminate confounding factors. One skilled in the art may be able to determine an appropriate control when one is desired.
“Cytokine” refers to a protein or peptide that generally is a mediator of local interactions in cell-cell communication, and is often involved in signalling. Many cytokines, especially interleukins and interferons, are secreted by immune cells and are recognized by cytokine receptors on other immune cells. Cytokines cause a variety of actions, such as activation, proliferation, and maturation of the cells. The term ‘cytokine’ and ‘growth factor’ have nearly identical meanings, but different historical roots: both are intended to be encompassed herein by “cytokine.” Peptides discovered by immunologists and hematologists tended to be called ‘cytokines’, while those discovered by neurobiologists or cancer biologist tended to be called ‘growth factors.’ Examples include NGF, FGF, EGF, (Nerve, Fibroblast, & Epidermal Growth Factors).
“Cytotoxic agent” refers to a compound, agent, or composition that has a toxic effect on cells. Cytotoxic agents are commonly used in chemotherapy to inhibit the proliferation of cancerous cells.
By “derivative” is meant a molecule or fragment thereof that has been chemically altered from a given state. Derivitization may occur during non-natural synthesis or during later handling or processing of a molecule or fragment thereof. Derivitization may result from a natural process, such as the steps of a cellular biochemical pathway. Recombinant nucleic acids or proteins that alter the naturally-occuring nucleic acid or amino acid sequence, respectively, may also be referred to as derivatives.
“Detect” or “detection” refers to identifying the presence, absence, or amount of the substance or state to be detected.
By “detectable label” is meant a molecule or fragment thereof that has been derivatized with an exogenous label (e.g., an isotopic label, fluoroscein, or radiolabel) that causes the molecule or fragment thereof to have different physicochemical properties to the naturally-occuring molecule or fragment thereof .
The terms “diagnosis” and “diagnostics” also encompass the terms “prognosis” and “prognostics”, respectively, as well as the applications of such procedures over two or more time points to monitor the diagnosis and/or prognosis over time, and statistical modeling based thereupon.
“DNA” refers to deoxyribonucleic acid and/or modifications and/or analogs thereof.
By “effective amount” or “therapeutically effective amount” of an agent is meant a sufficient amount of the agent to provide the desired therapeutic effect over the course of administration. An “effective amount” of an anti-cancer agent is a sufficient amount of the agent to at least partially inhibit or reverse tumor growth. Of course, undesirable effects, e.g., side effects, are sometimes manifested along with the desired therapeutic effect; hence a practitioner balances the potential benefits against the potential risks in determining what is an appropriate “effective amount.” The exact amount required may vary from subject to subject, depending on the species, age, and general condition of the subject, mode of administration, and the like. Thus, it is not possible to specify an exact “effective amount.” However, an appropriate “effective amount” or an “effective amount” of an anti-cancer agent in any individual case may be determined by one of ordinary skill in the art using only routine experimentation.
“ELISA” means enzyme-linked immunosorbent assay.
An “epitope” is a region on a macromolecule which is recognized by an antibody. Frequently it is in a short region of primary sequence in a protein and it is generally about 5 to 12 amino acids long (generally the size of the antigen binding site on an antibody). Carbohydrates, nucleic acids and other macromolecules may be antigens and have epitopes.
“Epitope tag” refers to an epitope added to the coding information of an expressed protein to provide a convenient antigenic site that can be recognized by a well-characterized antibody. The resultant protein is often referred to as a fusion protein. Epitope tags may be encoded at any point in the coding sequence, but are typically placed so as to produce an N- or C-terminal “tag.” More than one tag, possibly of more than one type, may be encoded in a coding sequence. Typical examples of epitope tags are the “FLAG” and “myc” tags. Some affinity tags, HIS and GST tags, for example, may also be used as epitope tags as well.
“Expression” refers to the product or products of a nucleic acid sequence as mediated by transcription and/or translation, and/or the qualitative or quantitative assessment of the amount of such products. For DNA the expression products referred to are generally the encoded RNA and/or protein. For RNA the referred to expression product is generally protein.
“FLAG-tag” refers to one of the first epitope tag systems. The FLAG epitope is recognized in calcium-dependent binding by commercially available M1 and M2 antibodies (Sigma-Aldrich Co., St. Louis, Mo.; U.S. Pat. Nos. 4,703,004, 4,782,137 and 4,851,341). The system can be used both for affinity purification and other immunological procedures. The flag peptide that was first used was an 11-amino-acid leader peptide of the gene-10 product from bacteriophage T7 fused at the amino-terminus of GAL4 (yeast transcription factor). At the time, there were no anti-GAL4 Ab commercially available, so a fusion protein with an epitope recognized by a commercially available antibody was prepared. The most widely used hydrophilic octapeptide now is DYKDDDDK (SEQ ID NO: 35) though recent studies suggest that a shorter peptide, DYKD (SEQ ID NO: 36), can be recognized with almost the same affinity by the M1 monoclonal antibody. Also, new tag sequences have been described for other monoclonal antibodies. The peptide MDFKDDDDK (SEQ ID NO: 37) is recognized by M5 and MDYKAFDNL (SEQ ID NO: 38) recognized by M2. The binding reaction is also dependent on calcium, so proteins can frequently be eluted from an affinity matrix by an EDTA-containing buffer. This system allows for the tag to be placed at either the amino-terminus (N-terminal) carboxy-terminus (C-terminal), or in association with other tags. It will not usually interfere with the fusion protein expression, proteolytic maturation or activity. Even if the tag is placed in the MHC class I molecule, it may not interfere with either alloantibody recognition or cytotoxic T cell-MHC interactions.
“Foreign substance” refers to a substance introduced from outside a cell, collection of cells, tissue, organ or organism. Such substances include, but are not limited to, nutrients, drugs, antibodies, vaccines, pharmaceutical compositions, DNA, RNA, liposomes, microorganisms, viruses, parasites, bacteria, yeast, fungi, mycobacteria, protein plaques, protein aggregates, collagen, extracellular matrix, other cells—living or dead, and/or debris. Such substances may also be exogenously produced substances that are or could be produced in the cell, collection of cells, tissue, organ or organism—for example, a protein or antibody.
“gDNA” refers to genomic DNA.
“GST-tag” refers to a glutathione S-transferase affinity or epitope tag. As an affinity tag, GST binds to the ligand glutathione, which is generally coupled to Sepharose beads. The GST-tag sometimes has the advantage of increasing the yield of expression and solubility of the recombinant protein, however removal of the GST-tag from the target protein is often necessary due to its large size. GST-tagged proteins produced with a cleavage site can allow single step, on-column GST-tag removal.
“HA-tag” refers to an epitope tag derived from haemagglutinin, generally of the amino acid sequence YPYDVPDYA (SEQ ID NO: 39).
“HIS-tag” refers to an affinity tag consisting of multiple consecutive histidine amino acids. Generally six (hexa-HIS) residues are used (SEQ ID NO: 40), or multiples thereof. His-tagged proteins have a high selective affinity for Ni2+ and a variety of other immobilized metal ions. Consequently a protein containing a His-tag is generally selectively bound to a metal ion charged medium while other cellular proteins bind weakly or are washed out with the binding or wash buffers. His-tags are small and therefore, tend to be less disruptive to the properties of the proteins on which they are attached.
“Homology” generally refers to the percent sequence identity, it may also be used to refer to close or equivalent structural and/or conformational homologues and/or analogues that may be reflected in direct comparisons of sequence (nucleic acid or protein) or may not, in which case the homology might generally be described as “cryptic”. Conformational or structural homology may be identified through structural comparisons, such as might be based on crystal structures, nuclear magnetic resonance (NMR) structures, secondary structure prediction, molecular modeling, binding assays and the like. Conformational and structural analogues may be identified through binding assays, enzymatic assays, phenotypic assays, and other methods known in the art.
“Humanized” or “humanizing” refers to methods for identifying, screening for, designing, making, and producing antibodies (e.g., methods of making recombinant antibodies from antibodies produced in an immune response in a non-human animal or fragments or sequences thereof) or the resultant antibodies themselves, which lower the chances of an undesired human immune response to portions of the antibodies recognized as foreign, for example a HAMA (human anti-murine antibody) or HACA (human anti-chimeric antibody) response. “Humanizing” methods generally aim to convert the variable domains of non-human antibodies to a more human form by recombinant construction of an antibody variable domain having, for example, both mouse and human character. Humanizing strategies are based on several consensual understandings of antibody structure data. First, variable domains contain contiguous tracts of peptide sequence that are conserved within a species, but which differ between evolutionarily remote species, such as mice and humans. Second, other contiguous tracts are not conserved within a species, but even differ between antibody producing cells within the same individual. Third, contacts between antibody and antigen occur principally through the non-conserved regions of the variable domain. Fourth, the molecular architecture of antibody variable domains is sufficiently similar across species that correspondent amino acid residue positions between species may be identified based on position alone, without experimental data.
Humanizing strategies tend to share the premise that replacement of amino acid residues that are characteristic of murine or other non-human sequences with residues found in the correspondent positions of human antibodies will reduce the immunogenicity in humans of the resulting antibody. However, replacement of sequences between species usually results in reduced affinity for the antigen from the resultant antibody. Preferably, the humanized antibody will exhibit the same, or substantially the same, antigen-binding affinity and avidity as the parent antibody. Preferably, the affinity of the antibody will be at least about 10% that of the parent antibody. More preferably, the affinity will be at least about 25% that of the parent antibody. Even more preferably, the affinity will be at least about 50% or more that of the parent antibody. Most preferable would be improved affinity as compared to the parent antibody. Methods for assaying antigen-binding affinity are well known in the art and include half-maximal binding assays, competition assays, and Scatchard analysis. The art of humanization therefore lies in balancing replacement of the original (e.g., murine) sequence to reduce immunogenicity with the need for the humanized molecule to retain sufficient antigen binding to be therapeutically useful. This balance has previously been struck using two approaches.
In one approach, exemplified by U.S. Pat. No. 5,869,619 and by Padlan ((1991) Mol Immunol 28: 489-498), characteristically human residues are substituted for murine variable domain residues that are determined or predicted (i) to play no significant chemical role in the interaction with antigen, and (ii) to be positioned with side chains projecting into the solvent. Thus, exterior residues remote from the antigen binding site are humanized, while interior residues, antigen binding residues, and residues forming the interface between variable domains remain murine.
In another more general approach, exemplified by U.S. Pat. No. 5,225,539 to Winter and by Jones et al. ((1986) Nature 321: 522-525), contiguous tracts of murine variable domain peptide sequence considered conserved are replaced with the corresponding tracts from a human antibody. In this more general approach, all variable domain residues are humanized except for the non-conserved regions implicated in antigen binding. To determine appropriate contiguous tracks for replacement, both Winter and Jones et al. (1986) utilized a classification of antibody variable domain sequences that had been developed previously by Wu and Kabat ((1970) J Exp Med. 132: 211-250).
Wu and Kabat (supra) pioneered the alignment of antibody peptide sequences, and their contributions in this regard were several-fold. First, through study of sequence similarities between variable domains, they identified correspondent residues that exhibited homology across all antibodies in all vertebrate species, inasmuch as they adopted similar three-dimensional structure, played similar finctional roles, interacted similarly with neighboring residues, and existed in similar chemical environments. Second, they devised a peptide sequence numbering system in which homologous immunoglobulin residues were assigned the same position number. One skilled in the art can unambiguously assign what is now commonly called Kabat numbering to any variable domain sequence without reliance on any experimental data beyond the sequence itself. Third, for each Kabat-numbered sequence position, Kabat and Wu (supra) calculated variability, by which is meant the finding of few or many possible amino acids when variable domain sequences are aligned. They identified three contiguous regions of high variability embedded within four less variable contiguous regions. Other workers had previously noted variability approximately in these regions (hypervariable regions) and posited that the highly variable regions represented amino acid residues used for antigen binding. Kabat and Wu (supra) formally demarcated residues constituting these variable tracts, and designated these “complementarity determining regions” (CDRs), referring to chemical complementarity between antibody and antigen. A role in three-dimensional folding of the variable domain, but not in antigen recognition, was ascribed to the remaining less-variable regions, which are now termed “framework regions”. Fourth, Kabat and Wu established a public database of antibody peptide and nucleic acid sequences, which continues to be maintained and is well known to those skilled in the art.
The humanization method disclosed by Winter and Jones using the Kabat classification results in a chimeric antibody comprising CDRs from one antibody and framework regions from another antibody that differs in species origin, specificity, subclass, or other characteristics. Subsequent developments in the field have been refinements within the scope of Winter to deal with loss of avidity for antigen observed with some humanized antibodies relative to the avidity of the corresponding mouse antibodies. (Avidity is a quantitative measure of partitioning of an antibody, in the presence of antigen under conditions approximating chemical equilibrium, between free and antigen-bound forms. For reactions in solution not subject to multivalent binding effects, avidity is the same as affinity, the biochemical equilibrium constant.).
U.S. Pat. No. 5,693,761 to Queen et al, discloses one refinement on Winter for humanizing antibodies and is based on the premise that ascribes avidity loss to problems in the structural motifs in the humanized framework which, because of steric or other chemical incompatibility, interfere with the folding of the CDRs into the binding-capable conformation found in the mouse antibody. To address this problem, Queen teaches using human framework sequences closely homologous in linear peptide sequence to framework sequences of the mouse antibody to be humanized. Accordingly, the methods of Queen focus on comparing framework sequences between species. Typically, all available human variable domain sequences are compared to a particular mouse sequence and the percentage identity between correspondent framework residues is calculated. The human variable domain with the highest percentage is selected to provide the framework sequences for the humanizing project. Queen also teaches that it is important to retain in the humanized framework, certain amino acid residues from the mouse framework critical for supporting the CDRs in a binding-capable conformation. Potential criticality is assessed from molecular models. Candidate residues for retention are typically those adjacent in linear sequence to a CDR or physically within 6 angstroms of any CDR residue.
In other approaches, criticality of particular framework amino acid residues is determined experimentally once a low-avidity humanized construct is obtained, by reversion of single residues to the mouse sequence and assaying antigen binding as described by Riechmann et aL, ((1988) Nature 332: 323-327). Another example approach for identifying criticality of amino acids in framework sequences is disclosed by U.S. Pat. No. 5,821,337 to Carter et al., and by U.S. Pat. No. 5,859,205 to Adair et al. These references disclose specific Kabat residue positions in the framework, which, in a humanized antibody may require substitution with the correspondent mouse amino acid to preserve avidity.
A second type of refinement to Winter is exemplified by Padlan et al. (1995) FASEB J. 9: 133-139; and Tamura et al. ((2000) J Immunol. 164: 1432-1441), which teach that increasing the proportion of characteristically human sequence in a humanized antibody will reduce that antibody's immunogenicity, and they accordingly disclose methods for grafting partial CDR sequences. Determination of the three-dimensional structure of antibody-antigen complexes showed that many residue positions assigned to the CDRs defined by Kabat and Wu rarely were directly involved in antigen binding. These references showed that grafting a subset of CDR residues would adequately transfer antigen binding in a humanized antibody.
The term “human” or “fully human” may refer to antibodies of human origin or produced having a human primary sequence to reduce chances of undesired immunogenicity in humans. For example, transgenic mice bearing human variable region sequences may be used to generate antibodies and the variable regions may be grafted to human constant regions to create fully human antibodies, or the mice may simply have fully human sequences allowing the direct generation of fully human antibodies in response to antigen. Human monoclonal antibodies can be prepared by the trioma technique; the human B-cell hybridoma technique (see Kozbor et al. (1983) Immunol Today. 4: 72-79) and the EBV hybridoma technique to produce human monoclonal antibodies (see Cole et al. (1985) in Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp. 77-96). Human monoclonal antibodies may also be produced by using human hybridomas (see Cote et al. (1983) Proc Natl Acad Sci. U.S.A. 80: 2026-2030) or by transforming human B-cells with Epstein Barr Virus in vitro (see Cole et al. (1985) in Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp. 77-96). Methods for producing fully human monoclonal antibodies, include phage display and transgenic methods, are known and may be used for the generation of human mAbs (for review, see Vaughan et al. (1998) Nat Biotech. 16: 535-539). For example, fully human anti-TAT-001 monoclonal antibodies may be generated using cloning technologies employing large human Ig gene combinatorial libraries (i.e., phage display) (Griffiths and Hoogenboom in: Protein Engineering of Antibody Molecules for Prophylactic and Therapeutic Applications in Man. Clark, M. (Ed.), Nottingham Academic, pp 45-64 (1993); see also, Hoogenboom and Winter (1992) J Mol Biol. 227: 381-388; Marks et al. (1991) J Mol Biol. 222: 581-597; and Burton and Barbas (1994) Adv Immunol. 57: 191-280). Along these lines, antibodies produced by the method of U.S. Pat. No. 5,840,479 are considered for the purposes of this invention “fully human” provided they provide comparable levels of anti-antibody response to other fully human antibodies as might be measured in an assay system known in the art, such as that devised by Stickler et al. ((2000) J Immunother. 23: 654-660). Fully human anti-TAT-001 monoclonal antibodies may also be produced with an antigen challenge using transgenic animals, such as mice engineered to contain human immunoglobulin gene loci as described in PCT Pat. Nos. such as WO 94/02602 and WO 98/24893 and U.S. Pat. Nos. 5,545,807; 5,545,806; 5,569,825; 5,625,126; 5,633,425; and 5,661,016 (see also, Jakobovits (1998) Exp Opin Invest Drugs. 7: 607-614; Marks et al. (1992) Biotechnology 10: 779-783; Lonberg et al. (1994) Nature 368: 856-859; Morrison (1994) Nature 368: 812-13; Fishwild et al. (1996) Nature Biotechnol. 14: 845-851; Neuberger (1996) Nature Biotechnol. 14: 826; and Lonberg and Huszar (1995) Intern Rev Immunol. 13: 65-93). Other human antibody technologies that may be of use in practicing the invention include, but are not limited to, those described in U.S. Pat. Nos. 6,657,103; 6,162,963; 6,319,690; 6,300,129; 6,673,986; 6,114,598; 6,075,181; 6,150,584; 5,770,429; 5,789,650; 5,814,318; 5,874,299; 5,877,397; 6,794,132; 6,406,863; 4,950,595; 5,286,647; 4,833,077; 4,716,111; 4,444,887; 4,594,245; 4,761,377; 4,434,230; 4,451,570; 4,464,465; and 4,529,694.
“Immune response” refers to a series of molecular, cellular, and organismal events that are induced when an antigen is encountered by the immune system. These may include the expansion of B- and T-cells and the production of antibodies. Aspects of an immune response, such as the expansion of T cell, B cell, or other antigen presenting cell populations may take place in vitro for administration to a subject. The immune response may provide a defense against foreign substances or organisms or aberrant host cells, such as cancer cells. Some tumors induce specific immune responses that suppress their growth. These often seem to be directed at peptides derived from antigens that might be mutated, inappropriately expressed, or overexpressed in the tumor cells. To determine whether an immune response has occurred and to follow its course, the immunized individual can be monitored for the appearance of immune reactants directed at the specific antigen. Immune responses to most antigens induce the production of both specific antibodies and specific effector T cells.
“Immunoassay” refers to one of a number of techniques for the determination of the presence or quantity of a substance, especially a protein, through its properties as an antigen or antibody. The binding of antibodies to antigen is often followed by tracers, such as fluorescence or (radioactive) radioisotopes, to enable measurement of the substance. Immunoassays have a wide range of applications in clinical and diagnostic testing. An example is solid-phase immunoassay in which a specific antibody is attached to a solid supporting medium, such as a PVC sheet. The sample is added and any test antigens will bind to the antibody. A second antibody, specific for a different site on the antigen, is added. This carries a radioactive or fluorescent label, enabling its concentration, and thus that of the test antigen, to be determined by comparison with known standards.
“Immunogen” refers to an antigen capable of inducing an immune response.
“Immunogenic” refers to the ability to induce an immune response. Typically a substance capable of inducing an immune response is referred to as immunogenic.
By “immunogenically effective amount” is meant an amount of a composition that is effective in inducing an immune response (e.g., a humoral or a mucosal immune response) when administered to a patient (e.g., human patient).
“Interact” refers to binding, proteolyzing, modifying, regulating, altering, and/or the like, generally as governed by context. Often it refers simply to binding. Generally it refers to direct interaction, but it may also refer to indirect interaction such as through a biochemical or genetic pathway.
A polynucleotide may be “introduced” into a cell by any means known to those of skill in the art, including transfection, transformation or transduction, transposable element, electroporation, particle bombardment, and infection. The introduced polynucleotide may be maintained in the cell stably if it is incorporated into a non-chromosomal autonomous replicon or integrated into the fungal chromosome. Alternatively, the introduced polynucleotide may be present on an extra-chromosomal non-replicating vector and be transiently expressed or transiently active. “Introduced” may also be used in other context defmed ways, such as in the the recombinant “introduction” of mutations into a nucleic acid sequence.
“In vitro binding assay” refers to assays reagents and/or systems for detecting and/or measuring, qualitatively and/or quantitatively, the binding between a protein, DNA, and/or RNA and another specific substance or complex, such a protein, DNA, RNA, cyclized peptide, or small molecule in vitro. The assay may be cell-based, such as in the yeast two hybrid and variants thereupon, or, for example, as in CAT or luciferase assays in cultured cells, and may be immunologically-based, such as with the use of immunoaffinity columns, ELISA assays, and the like, but assays in a live animal or person are excluded and considered “in vivo”.
An “isolated” and/or “substantially pure” polynucleotide or nucleic acid molecule is free of genes that, in the naturally occurring genome of the organism from which the nucleic acid molecule of the invention is derived, flank the nucleic acid. The term includes, for example, a recombinant DNA that is incorporated into a vector; into an autonomously replicating plasmid or virus; or into the genomic DNA of a prokaryote or eukaryote; or that exists as a separate molecule (e.g., a cDNA, genomic, or coding fragment produced by PCR or restriction endonuclease digestion) independent of other sequences. It also includes a recombinant DNA that is part of a hybrid gene encoding additional polypeptide sequence. A polynucleotide corresponding to a polypeptide which can be identified by one skilled in the art such as through the use of Mascot (Matrix Science, Boston, Mass.) and translated MRNA databases and BLAST (Gish and States (1993) Nat Genet. 3: 266-272; Alschutl et al. (1997) Nucleic Acids Res. 25: 3389-3402; Madden et al. (1996) Methods Enzymol. 266: 131-141; Altschul et al. (1990) J. Mol. Biol. 215: 403-410) is also considered isolated. Fragments or partial sequences when considered with other data, or when they uniquely identify a full-length sequence, may be used to identify full-length sequences, which can then also be considered isolated. Such sequences may be amplified from an appropriate library through techniques such as PCR, produced by oligonucleotide synthesis, or through recombinant techniques known in the art. Alternatively, a polynucleotide is considered isolated if it has been altered by human intervention, or placed in a locus or location that is not its natural site, or if it is introduced into one or more cells. Having been isolated, a polynucleotide may readily be manipulated by molecular biological, recombinant, and other techniques and used or present in relatively pure or purified states, or be used or present in combinations, mixtures, solutions, compounds and complex isolates, such as cell lysates. The isolated polynucleotide need not be isolable, separable, or purifiable from any such compositions. The skilled person can readily employ nucleic acid isolation procedures to obtain isolated TAT-001 polynucleotides.
A polypeptide (or fragment thereof) may be said to be “isolated” when physical, mechanical or chemical methods have been employed to remove the polypeptide from cellular constituents. An “isolated polypeptide,” “substantially pure polypeptide,” or “substantially pure and isolated polypeptide” is typically considered removed from cellular constituents and substantially pure when it is at least 60% by weight, free from the proteins and naturally occurring organic molecules with which it is naturally associated. Preferably, the polypeptide is at least 75%, more preferably at least 90%, and most preferably at least 99% by weight pure. A substantially pure polypeptide may be obtained by standard techniques, for example, by extraction from a natural source (e.g., colon tissue or cell lines), by expression of a recombinant nucleic acid encoding a TAT-001 polypeptide, or by chemically synthesizing the polypeptide. Purity can be measured by any appropriate method, e.g., by column chromatography, polyacrylamide gel electrophoresis, or HPLC analysis. A polypeptide for which the encoding nucleic acid sequence has been cloned, or can be derived or identified by one skilled in the art, such as through the use of Mascot (Matrix Science, Boston, Mass.) and translated mRNA databases and BLAST (Gish and States (1993) Nat Genet. 3: 266-272; Alschutl et al. (1997) Nucleic Acids Res. 25: 3389-3402; Madden et al. (1996) Methods Enzymol. 266: 131-141; Altschul et al. (1990) J. Mol. Biol. 215: 403-410) is also considered isolated. Fragments or partial sequences when considered with other data, or when they uniquely identify a full-length sequence, may be used to identify full-length sequences, which can then also be considered isolated. Alternatively, a polypeptide is considered isolated if it has been altered by human intervention, or placed in a location that is not its natural site, or if it is introduced into one or more cells. The skilled person can readily employ protein isolation, separation, and/or purification procedures to obtain an isolated polypeptide, such as a TAT-001 polypeptide after expression by a recombinant polynucleotide encoding the polypeptide. A purified TAT-001 polypeptide molecule will be substantially free of other proteins or molecules which impair the binding of TAT-001 to antibody or other ligand; may or may not be of one or more isoforms; may or may not have one or more post-translational modifications; and may or may not be in native conformation or denatured. The nature and degree of isolation and purification will depend on the intended use. Having been isolated, a polypeptide may readily be manipulated by molecular biological, recombinant, and other techniques and used or present in relatively pure or purified states, or be used or present in combinations, mixtures, solutions, compounds and complex isolates, such as cell lysates. The isolated polypeptide need not be isolable, separable, or purifiable from any such compositions. Embodiments of a TAT-001 polypeptide include a purified TAT-001 polypeptide and a functional, soluble TAT-001 polypeptide. In one form, such fuictional, soluble TAT-001 polypeptides or fragments thereof retain the ability to bind antibody or other ligand.
“Mass spectrometer” refers to a gas phase ion spectrometer that measures a parameter which can be translated into mass-to-charge ratios of gas phase ions. Mass spectrometers generally include an inlet system, an ionization source, an ion optic assembly, a mass analyzer, and a detector. Examples of mass spectrometers are time-of-flight, magnetic sector, quadrupole filter, ion trap, ion cyclotron resonance, electrostatic sector analyzer and hybrids of these.
“Mass spectrometry” refers to a method comprising employing an ionization source to generate gas phase ions from an analyte presented on a sample presenting surface of a probe and detecting the gas phase ions with a mass spectrometer.
“Method of screening” means that the method is suitable, and is typically used, for testing for a particular property or effect of a large number of compounds, including the identification and possible isolation of an individual compound or compounds based a particular property such as binding or not binding to a target molecule. Typically, more than one compound is tested simultaneously (as in a 96-well microtiter plate), and preferably significant portions of the procedure can be automated. “Method of screening” also refers to methods of determining a set of different properties or effects of one compound simultaneously. Screening may also be used to determine the properties for a complete set of compounds in a non-selective fashion, or may be used to select for a particular property or properties, such as might be desired to reduce the number of candidate compounds to be examined in later screening efforts or assays. Screening methods may be high-throughput and may be automated.
“MHC” means Major Histocompatibility Complex.
“Modulating” refers to fixing, regulating, governing, influencing, affecting, and/or adjusting one or more characteristics of a macromolecule or molecular, cellular, tissue, organ, or organismal phenotype. Modulation need not have contemporaneous effect, or be direct.
“Modulator” refers to an agent capable of modulating. Modulators are generally compounds or compositions. Compounds may be administered in a pure form, substantially pure form, and/or in mixtures, solutions, colloids, adjuvants, and/or solid mixtures containing the compound or compounds, particularly when required for delivery of the compound or compounds to the site or sites of action. Administration may be by any mode of delivery appropriate to the compound or compounds being delivered and their target cell or cells known in the art, for example, direct contact, ingestion, or injection. Modulators may be detected by screening methods known in the art, for example by treating with compounds, or modifications and analogs of substances and comparing to control samples. Such screening methods may be high-throughput.
“Myc tag” refers to an epitope tag derived from myc protein, generally of the sequence amino acid EQKLISEEDL (SEQ ID NO: 41). A number of different antibodies are known to recognize the myc epitope tag, for example 9B11 and 9E10.
“mRNA” means messenger ribonucleic acid.
“Operably linked” means incorporated into a genetic construct so that expression control sequences effectively control expression of a coding sequence of interest.
“Overexpression” is primarily used to describe the relative quantity or expression pattern of a particular peptide or protein as greater between one condition and another. Overexpression may also be used to refer to RNA expression, however, RNA expression is not predictive of protein expression. Generally, overexpression is measured compared to a normal or control condition. For example, a cell expressing 5 micrograms of protein X upon treatment with a compound, could be said to be overexpressing protein X compared to an untreated cell expressed 1 microgram. Due to experimental variation it is preferable for such measurements to be statistically significant and for the methods used to produce such measurements to be reasonably accurate and reproducible. Overexpression need not be a direct result of gene expression through transcription, and in some cases localization may be relevant. For example, a cell might express 5 micrograms of protein X under both treated and untreated conditions, but in the treated cells 100% of the protein might be present at the plasma membrane, as compared to 15% in the untreated cells. This might be described as overexpression relative to the plasma membrane.
Similarly, overexpression may refer to expression at the level of an individual cell, or of a population of cells, such as a tissue, organ, or organism. For example, PCNA, the proliferating cell nuclear antigen is expressed in cells undergoing DNA replication (S phase of the cell cycle). A comparison of PCNA levels in an S phase normal cell and an S phase tumor cell might show the levels to be equivalent. However, comparison of PCNA levels in the normal tissue vs. the tumor might show overexpression of PCNA in the tumor because there are more cells undergoing DNA replication in the tumor (the length of S phase is relatively constant, but the overall cell cycle tends to be shorter in tumor cells, and they divide more frequently). Measurements may be based on the relative weight or mass of samples, their relative cell numbers or volumes, or other reasonable criteria for a particular assessment. For example, whether there is a safe and effective concentration of a radiocompound as estimated by its potential number of binding sites per unit of volume might best be assessed by determining relative expression by volume, while another compound, such as an activator of apoptosis might be better assessed in terms of the expression level on a per cell basis. Potential antigens for immunotherapy would preferably be overexpressed on the plasma membrane of human colon cancer tumor cells relative to the plasma membranes of normal tissue or cells. More preferably potential antigens would also be overexpressed as compared to other normal tissue within the organism.
The methods initially used to identify TAT-001 expression herein (see Example 4) permit peptide quantity to be used to infer protein quantity, particularly if the peptide is a unique peptide, or if there are quantities known for multiple peptides from a particular protein. An example of the accuracy of this inference is presented in
“Overexpression” may also be used to describe a vector used for the production of, high levels of a particular gene product or to describe the resulting gene product, generally for a particular end, such as purification of the protein or experimental assessment of the phenotype associated with overexpression. Some proteins may be difficult to overexpress given toxicity or other factors, so the “high level” of expression may vary from protein to protein, and in this context represents a goal, expression being preferably higher than in the natural state of a protein's expression under corresponding conditions.
“PCR” means polymerase chain reaction.
“Percent (%) sequence identity” and “% identical” refer to the percentage of nucleotides or amino acids identical between two sequences or segments thereof, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity over the aligned portions of the sequence, and not considering any conservative substitutions as part of the sequence identity. In general, for proteins, the length of comparison sequences will be at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 amino acids, preferably at least 100, 110, 120, 130, Or 140 amino acids, more preferably at least 150, 160, 170, or 180 amino acids, and most preferably at least 190 amino acids, or at least 191 amino acids or more. For nucleic acids, the length of comparison sequences will generally be at least 25 nucleotides, preferably at least 50 nucleotides, more preferably at least 75 nucleotides, at least 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, or 550 nucleotides, and most preferably at least 570 nucleotides, at least 573 nucleotides, or more. One skilled in the art should be able to determine an appropriate length for comparison to the TAT-001 sequences or fragments thereof to meet particular aims, see for examples, “substantial identity” below. Manual alignment and visual inspection can be used to determine the % sequence identity. A number of softwares can also be used to determine the % sequence identity values of two (or in some cases more) sequences, for example, NCBI BLAST2.0 software as defined by Altschul et al. (1997) Nucleic Acids Res. 25: 3389-3402, and with the parameters set to default values and the complexity filter off. In one aspect of the invention (in the methods of the invention, and to determine if a sequence is within the scope of the invention), the preferred software for determining percent sequence identity is bl2seq (Tatusova and Madden (1999) FEMS Microbiol Lett. 174: 247-250). For nucleotide sequences, the BLASTN program of bl2seq is preferred with preferred parameters of a wordlength (W) of 11, an expectation (E) of 10, an open gap penalty of 5, an extend gap penalty of 2, a gap x_dropoff of 50, a match reward of 1 and a match penalty of −2, the complexity filter off, and a comparison of both strands (in case a complementary strand is used in the comparison). It is understood that for the purposes of determining sequence identity when comparing a DNA sequence to an RNA sequence, a thymine nucleotide is equivalent to a uracil nucleotide. For amino acid sequences, the BLASTP program of bl2seq is preferred with preferred parameters of wordlength (W) of 3, an expectation (E) of 10, an open gap penalty of 11, an extend gap penalty of 1, a gap x_dropoff of 50, the complexity filter off, and the BLOSUM62 scoring matrix (see, e.g., Henikoff(1989) Proc. Natl. Acad. Sci U.S.A. 89: 10915-10919). Percent sequence identity is denoted in the bl2seq output as “identities” and may be presented as a fraction of the number of identities over the length of the aligned segment of sequence and/or a percentage. Segments less than a full sequence are delimited in the software output as a result of the software parameters for homology “dropoff” and are not arbitrarily chosen to yield a particular outcome. If multiple alignments of differing lengths are generated for the same pair of sequences in the software output the most appropriate length alignment as determined by one skilled in the art may be taken to have the % identity to be used. For example, if an alignment of two proteins, one SEQ ID NO. 5 and one a non-human orthologue, with bl2seq produces an alignment over the full length of the proteins with 70% identity and a slightly different alignment of the C-termini with 78% identity, the 78% may be more appropriate when use of the C-termini as antigens is considered, while the 70% may be more appropriate when considering using full length proteins to screen against a library of compounds for comparison to a similar screen using SEQ ID NO. 5 to identify compounds that may be used across species to bind TAT-001. In a case involving two genomic DNAs, the % identity for exons might be expected to be higher than for an overall gene locus and both may be of use in delimiting the loci of homologous genes. Preferably a sequence of the invention is at least about 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99% identical to a TAT-001 sequence disclosed herein (e.g., SEQ ID NO. 5).
“Percent (%) sequence similarity” and “% similar” refer to the percentage of nucleotides or amino acids identical between two sequences or segments thereof, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity over the aligned portions of the sequence, plus the percentage of conservative substitutions. In general, for proteins, the length of comparison sequences will be at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 amino acids, preferably at least 100, 110, 120, 130, Or 140 amino acids, more preferably at least 150, 160, 170, or 180 amino acids, and most preferably at least 190 amino acids, or at least 191 amino acids or more. For nucleic acids, the length of comparison sequences will generally be at least 25 nucleotides, preferably at least 50 nucleotides, more preferably at least 75 nucleotides, at least 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, or 550 nucleotides, and most preferably at least 570 nucleotides, at least 573 nucleotides, or more. One skilled in the art should be able to determine an appropriate length for comparison to the TAT-001 sequences or fragments thereof to meet particular aims, see for examples, “substantial identity” below. Manual alignment and visual inspection can be used to determine the % sequence similarity. The same or similar softwares may also be used as with percent sequence identity, but the preferred software is, again, bl2seq with parameters per those given for percent sequence identity. Percent sequence similarity is denoted in the bl2seq output as “positives” and may be presented as a fraction of the number of positives over the length of the aligned segment of sequence and/or a percentage. Preferably a sequence of the invention is at least about 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99% similar to a TAT-001 sequence disclosed herein (e.g., SEQ ID NO. 5).
By “pharmaceutically acceptable” carrier is meant a pharmaceutical vehicle comprised of a material that is not biologically or otherwise undesirable, i.e., the material may be administered to an individual along with the selected active agent without causing any undesirable biological effects or interacting in a deleterious manner with any of the other components of the pharmaceutical formulation in which it is contained. Carriers may include excipients and other additives such as diluents, detergents, coloring agents, wetting or emulsifying agents, pH buffering agents, preservatives, and the like. Similarly, a “pharmacologically acceptable” salt, ester, amide, prodrug, or derivative of a compound as provided herein is a salt, ester, amide, prodrug, or derivative that is not biologically or otherwise undesirable.
“Plasmid” refers to a small, independently-replicating, nucleic acid that can be transferred from one organism to another. Plasmids may be linear or circular. Linearized plasmids may also concatemers. ‘Stringent’ plasmids occur at low copy number in cells, ‘relaxed’ plasmids at high copy number, circa 10-50 copies per cell. Plasmids can become incorporated into the genome of the host, or can remain independent. An example is the F-factor of E. coli. Plasmids may be used to transfer genes, and plasmids carrying antibiotic-resistant genes can spread this trait rapidly through the population. Plasmids are widely used in genetic engineering as vectors, and may be recombinant.
“Post-translational modifications” or “PTMs” refers to changes that occur to proteins after peptide bond formation has occurred. Examples, not intended to be limiting, include glycosylation, acylation, limited proteolysis, phosphorylation, and isoprenylation.
“Probe” generally refers to a TAT-001 binding complex or binding molecule used in the detection, quantification, and/or qualitative assessment of a TAT-001 nucleic acid or TAT-001 polypeptide in a sample. Non-limiting examples, in addition to those discussed throughout, include a probe nucleic acid used to detect a mutant TAT-001 nucleic acid in a patient sample; a probe antibody used to quantitate the amount of TAT-001 polypeptide in a sample; a binding molecule used to determine if the native conformation of the protein is maintained, for separation from a sample, or for assessing relative purity. A probe is preferably a TAT-001 binding molecule, more preferably a TAT-001 nucleic acid, TAT-001 polypeptide, or TAT-001 antibody, but need not be, such as in the case of determining purity by probing for contaminants.
“Promoter” refers to a region of DNA, generally and preferably from a gene's genomic locus, which can be reasonably demonstrated to be involved in regulating the expression of a gene. This includes both a basal level of transcription and those elements, such as enhancer elements, repressor elements and the like which are capable of regulating gene expression under certain conditions, such as binding by a transcription factor. Generally the region includes a region of DNA to which RNA polymerase binds before initiating the transcription of DNA into RNA. The nucleotide at which transcription starts is designated +1 and nucleotides are numbered from this with negative numbers indicating upstream nucleotides and positive downstream nucleotides. Most factors that regulate gene transcription do so by binding at or near this basal promoter and affecting the initiation of transcription. Most eukaryotic promoters regulated by RNA polymerase II have a Goldberg-Hogness or “TATA box” that is centered around position −25 and has the consensus sequence 5′-TATAAAA-3′ (SEQ ID NO: 42). Several promoters have a CAAT box around −90 with the consensus sequence 5′-GGCCAATCT-3′ (SEQ ID NO: 43).
“Protein,” “peptide,” or “polypeptide” refer to any of numerous naturally occurring, recombinantly derived, or synthetic, sometimes extremely complex (such as an enzyme or antibody) substances that consist of a chain of four or more amino acid residues joined by peptide bonds. The chain may be linear, branched, circular, or combinations thereof. Intra-protein bonds also include disulfide bonds. Protein molecules contain the elements carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally other elements (such as phosphorus or iron). Preferably, polypeptides are from about 10 to about 1000 amino acids in length, more preferably 10-200 amino acids in length. Herein, “protein” is also considered to encompass fragments, variants and modifications (including, but not limited to, glycosylated, acylated, myristylated, and/or phosphorylated residues) thereof, including the use of amino acid analogs, as well as non-proteinacious compounds intrinsic to enzymatic function, such as co-factors, or guide templates (for example, the template RNA associated with proper telomerase function). In context, “protein” may be used to refer to a full-length (encompassing the whole of the coding sequence) or full-length post-translationally modified polypeptide as encoded by a particular nucleic acid sequence, and “peptide” may be used to refer to short amino acid sequences (roughly 4 to 50 amino acids) or non-full-length polypeptides, but this should not be taken as limiting relative to the above definition.
“Recombinant” is an adjective referring to a nucleic acid sequence produced or altered through use of recombinant DNA technology or gene splicing techniques and/or nucleic acids or proteins produced therefrom, such as through transcription and/or translation. As used herein, the term also encompasses nucleic acids and proteins altered from their natural state or produced through other man-made techniques, for example, oligonucleotide or protein synthesis, or PCR.
A “reference level” generally refers to a particular level of an indicator used as a benchmark for assessment, which may come from a single data point or be derived from multiple data points, such as a cut-off median, and may be measured directly, indirectly, or calculated. Typically the reference level will be used as a reference to a normal or control level allowing the identification of levels that deviate from the normal. For example, a reference level for expression of a particular protein in a patient with cancer may be used in comparison with appropriate samples from patients to determine whether their individual level of the particular protein's expression indicates the presence of cancer or not. An algorithm can be designed, such as by those with skill in the art of statistical analyses, which will allow the user to quickly calculate a reference level for use in making predictions or monitoring a particular state or condition. With additional data, generated similarly to the manner described herein, it may be possible to more accurately defme appropriate reference levels. The algorithm and reference level can be used to generate a device that will allow the end user to input levels for a characteristic and quickly and easily determine the status or risk index of an individual through comparison of the level that was input and the reference level. Similarly, it is possible to provide a device that indicates the status of an individual relative to a reference level. One skilled in the art can determine an appropriate reference level when one is desired.
“Reference range” generally refers to a particular range of an indicator used as a benchmark for assessment, such as a mean deviation cut-off multiple points range within which, for example, “normal” or “disease” is expected to fall. In one example, the range of test values expected for a designated population of individuals, e.g., 95 percent of individuals that are presumed to be healthy (or normal). A reference range may be useful in rninimizing variation possible with a single reference sample. Generally, all reference ranges include a set of two values with one value designated as an upper reference range limit and another designated as a lower reference range limit. A range may be sub-divided into ranges of differing significance, hence where within a range a value falls may provide additional correlates or probabilities. For example, a range for normal expression of a protein is 0.1 to 0.4 micrograms per liter of plasma, and above the reference level of 0.4 μg/l colon cancer is indicated, however, within the normal range a range of 0.3 to 0.4 μg/l may indicate an 80% probability of dysplastic or pre-cancerous tissue lining the colon. An algorithm can be designed, such as by those with skill in the art of statistical analyses, which will allow the user to quickly calculate a reference range for use in making predictions or monitoring a particular state or condition. With additional data it may be possible to more accurately define appropriate reference ranges. The algorithm and reference range can be used to generate a device that will allow the end user to input levels for a characteristic and quickly and easily determine the status or risk index of an individual through comparison of the level that was input and the reference range. Similarly, it is possible to provide a device that indicates the status of an individual relative to a reference range. One skilled in the art can determine an appropriate reference range when one is desired.
“Reference sample” generally refers to a sample used as a control, that is chosen to represent a normal, or that is designated a normal based on statistical evaluation (for example, having a value for a relevant characteristic that falls within the mean plus or minus 2 standard deviations for a given population). A reference sample may be used as a benchmark for assessment or from which such benchmarks may be derived, thus a reference sample may also be a sample chosen as representative of a particular condition or state, such as presence of a disease. Determiination of appropriateness of use as a reference sample may be judged by one skilled in the art before or after measurement of the desired characteristics for which the sample will be used as a reference or as part of a population of reference samples, depending on the reasonableness to do so. For example, it may be reasonable for a group of patients to be designated as reference samples and “normal” for a mutant phenotype they do not display, and measurements of a panel of genes for gene expression may then be used as a reference range for normals relative to that phenotype. In another example, the reference level can be a level determined from a prior sample taken from the same subject. Or, for example, it may be reasonable to determine the TAT-001 concentration in blood from a random sampling of the population (the reference sample thereby being a random sample) and using statistical methods to delineate a normal range, or reference range. Or, a population of samples from untreated patients with melanoma and a population of patients with melanoma undergoing treatment might be useful in providing reference samples for comparison of the effects of a second therapy on protein expression levels. In some contexts, “reference sample” may simply refer to a sample of known quantity, of normal quantity, or readily determinable quantity for comparison. Reference samples may be used to determine reference ranges and/or reference levels for characteristics of the samples. One skilled in the art may be able to determine an appropriate reference sample when one is desired.
“Ribozyme” refers to an RNA molecule that can break or form covalent bonds in their own sequence or another molecule. i.e., it is capable of acting as an enzyme. The reactions observed include cleaving themselves or other RNA molecules, ligation, and trans-splicing. Ribozymes greatly accelerate the rate of the reaction, and can show extraordinary specificity with respect to the substrates it acts on and the products it produces. There are three common types of ribozymes: 1) self-cleaving, both of the hammerhead ribozyme and hairpin ribozyme varieties 2) self-splicing (introns) 3) ribonuclease P. Ribozymes can be generated to cleaving any desired substrate. There is a recognition complex for this enzyme consisting of oligonucleotide hybridized to external guide sequence, making it possible to synthesize a guide sequence and create a substrate for ribozyme attack. Synthetic genes for guide sequence may be transformed to a cell (e.g., a mammalian cell) through tissue-specific biological vectors or oligonucleotides encapsulated in liposomes. Thus, this technique is suitable for inactivation of any RNA inside the cell or in vitro. It may be used as the tool for inactivating genes in mammalian cells.
“RNA” refers to ribonucleic acid and/or modifications and/or analogs thereof.
“RNA equivalent” refers to an RNA sequence corresponding to a DNA or amino acid sequence. Such equivalents may correspond directly to the original sequence (in the case of a protein the “coding sequence”), or may include additional sequence, such as untranslated regions and introns. In the case of an RNA equivalent for DNA the correspondence may be complementary to the DNA strand or anti-sense, allowing for the fact that in RNA “U” replaces “T” in the genetic code.
A “solid support” is a material, essentially insoluble under the given solvent and temperature conditions, with which one or more capture reagents is retained (attached, bound, disposed thereon) and/or made more easily separable from a sample the capture reagents are brought into contact with. In a preferred embodiment, the solid support is covalently coupled to one or more capture reagents capable of directly or indirectly binding a target molecule, such as a protein. When the target molecule is a protein, the capture reagent preferably comprises an immunoaffinity reagent. The solid support is also preferably a particle such as a bead or sphere in the micron or submicron size range, referred to herein as “beads.” Preferably beads are 200 microns or less, more preferably 150 microns or less, most preferably 100 microns or less. The solid support is preferably made of materials that may include one or more of the following: silica, polyacrylate, polyacrylamide, a metal, polystyrene, latex, nitrocellulose, exocellulose, dextran, sepharose, polypropylene, and nylon. Preferably, the solid support is able to be affected by a magnetic field. In such a case, the solid support may have a magnetite core. Other preferred forms of solid supports include filters, planar surfaces, and plate wells (such as those found in high-throughput plate formats, or used for ELISA). Preferably plates are relatively rigid or self-supporting to allow for easy handling during manufacturing and easy handling during use by the end user (a human or a robot). Preferably the plate may be made of polymeric (especially thermoplastic) materials, glass, metallic materials, ceramic materials, elastomeric materials, coated cellulosic materials and combinations thereof such as epoxy impregnated glass mats. In a more preferable embodiment, the plate is formed of a polymeric material including but not limited to polyethylene, acrylic, polycarbonate and styrene. The wells can be made by injection molding, drilling, punching and any other method well known for forming holes in the material of selection. Such plates are well known and commercially available from a variety of sources in a variety of well numbers and designs. Most common are 96 and 384 well plates. Plates are typically 5 inches (127 mm) long and 3.4 inches (86.4 mm) wide. The plate thickness can vary but are generally 0.5 inches (12.7 mm) for a standard plate and 1.75 inches (44.45 mm) for a deep well plate. The well format will be determined by the end users needs, but it can have numerous configurations and the wells do not necessarily need to be all of the same shape or size. Especially with the smaller sized wells, the wells may have the same or different volumes. The wells may also have different shapes. For example, the wells of the present invention may have round, rectangular, teardrop, square, polygonal and other cross-sectional shapes or combinations of them. Virtually any shape that is required for the product may be provided. Typically, it has the wells arranged in uniformly spaced rows and columns for ease of use. Filters may be woven or non-woven, including but not limited to multilayer or composite filters. Not all layers of a multilayer filter need retain, bind, be attached to, etc. a capture reagent. Filters can be chosen with respect to their properties in a way corresponding to the requirements of the respective sample and desired purification, so that the necessary purity class for the medium to be filtered is ensured. In a preferred way, the particle retention of the filters used is >60 micrometers, preferably>100 micrometers. Columns are also preferred solid supports, but are generally a secondary support retaining another form of support such as beads and filters. Solid supports may be used in any combination. For example a column may contain multiple compartments allowing flowthrough that contain different beads with different attached capture reagents as well as filters with attached capture reagents.
“Specific binding,” “selective binding,” and “specific interaction” or “selective interaction” refer to an interaction, even briefly, between TAT-001 and one or more molecules, compounds, or complexes, wherein the interaction is dependent upon the primary amino acid sequence (or other structural elements in a non-peptidic portion of a molecule), post-translational modifications to the amino acid sequence or its modifications, and/or the conformation of TAT-001 and/or its modifications. A molecule that exhibits specific binding toward another molecule may be said to be “specific for” the other molecule. Generally specific binding provides the ability for two molecular species concurrently present in a heterogeneous (non-homogeneous) sample to bind to one another preferentially over binding to other molecular species in the sample. In other words, “specificity” refers to the potential to bind one unique chemical structure more strongly than a number of similar alternatives. Typically, a specific binding interaction will discriminate over adventitious binding interactions in the reaction by at least two-fold, more typically more than 10- to 100-fold. When used to detect an analyte, specific binding is sufficiently discriminatory when determinative of the presence of the analyte in a heterogeneous (inhomogeneous) sample. Typically, the affinity or avidity of a specific binding reaction is least about 10−4 M, with specific binding reactions of greater specificity typically having affinity or avidity of at least 10−6 M to at least about 10−12 M. It may also refer to binding to self, or other molecules of the same protein, as in the forming of dimers and other multimers. Selective binding might also be generally described as specific binding, but may also be used for example to connote a use in a discriminatory separation, diagnostic, or identification technique or a discriminatory property beyond simply recognizing the presence of the binding target in a sample—for example an antibody may be selective for different members of a closely related protein family, for specific modified forms of a protein (e.g., a phosphorylated form vs. a non-phosphorylated form), or specific conformations of a protein (e.g., PrPC vs. PrPSc). Specific and/or selective binding may also be described as “recognition” or “recognizing” of a molecule by a binding molecule.
“Small molecule” typically refers to a non-peptidic molecule that has a low molecular weight, often, though not always, between 1 dalton and 5 kilodaltons (kDa). Small molecules may penetrate cell membranes and the blood brain barrier more easily than larger molecular weight compounds such as proteins, peptides and carbohydrates. Small molecules generally need to be less than 600 daltons to pass the blood brain barrier. Typically small molecules are produced through chemical reactions or synthesis, though this is not always the case, and they rarely provoke an immune response. Preferably small molecules of the invention are less than 5 kDa, more preferably they are less than 1 kDa, Most preferably they are less than 600 daltons.
“Substantial identity” (also “substantial amino acid sequence identity”, “substantial nucleic acid sequence identity”, “substantial sequence identity”, and the like) refers to a sequence that, although not necessarily of high homology, maintains enough of the original sequence in the form of identical amino acid, or nucleotide residues, or conservative substitutions thereof, or which, although differing in linear sequence maintains enough structural similarity (e.g., maintaining within two angstroms the positions of critical contact residues) to maintain binding or another finction within several orders of magnitude of the original sequence. “Substantial identity” may be used to refer to various types and lengths of sequence, such as full length sequence, epitopes or immunogenic peptides, functional domains, coding and/or regulatory sequences, exons, introns, promoters, and genomic sequences. One skilled in the art can determine appropriate comparisons. For example, potential additional TAT-001 genomic clones may be initially identified by substantial identity over the length of a known TAT-001 genomic sequence, or by substantial identity of TAT-001 coding exons within a corresponding (exons fall essentially in the same order) genomic sequence. Or, potential homologues or xenologues may be identified by substantial identity of appropriate portions of their coding sequences to identified functional domains, such as may be necessary to identify an orthologue containing additional functional domains (for example, insertions or gene fusions) that would not otherwise be identified based on percent sequence identity comparison over the full length of the protein. Some non-limiting examples and methods may be found in Bazan et aL. (1989) Proc Natl Acad Sci U.S.A. 86: 9642-9646; Simmer et al. (1990) J Biol Chem. 265: 10395-10402; Storm and Sonnhammer (2001) Bioinformatics 17: 343-348; Kong and Ranganathan (2004) Brief Bioinform. 5: 179-192; Sonnhammer and Kahn (1994) Protein Sci. 3: 482-492; and Yamaguchi et al. (2002) Plant Cell 14: 2957-2974. Substantial identity may be a more appropriate standard than percent sequence identity for short sequences, such as peptide antigens that can potentially be used to confer an immune response with specificity for TAT-001, but that, because of their short length, easily fall below the desired percent sequence identity with minor alterations, such as conservative amino acid substitutions, that may have little or no impact on the function as a TAT-001 immunogen. Substantial identity also encompasses the use of cryptic epitopes, such as for mimicking the antigenicity of TAT-001. TAT-001 sequences not otherwise considered to have substantial identity on such a finctional basis may readily be assessed based on the percent sequence identity. Polypeptides having at least 40% sequence identity with a human TAT-001 polypeptide (SEQ ID NO: 1, 3, 5, and 8) are considered substantially identical and useful in the methods of the invention. Preferably, sequence identity is at least 40%, or at least 50%, or at least 60%, more preferably the sequence identity is at least 70%, most preferably the sequence identity is at least 80% or 90 or 95 or 99%, or any integer from 40-100% sequence identity in ascending order. Similarly, polypeptides having at least 50% sequence identity with a TAT-001 xenologue polypeptide, particularly potential orthologues (e.g., SEQ ID NO: 12, 15, 18, 21, 25, 28, and 32) are considered substantially identical to the xenologue and may also be useful in the methods of the invention. Polynucleotides encoding a TAT-001 polypeptide or having at least 40% sequence identity with a human TAT-001 nucleic acid (SEQ ID NO: 2, 4, 6, 7, 9, and 10) are also useful in the methods of the invention. Preferably, the sequence identity is at least 40%, or at least 50%, or at least 60%, more preferably the sequence identity is at least 70%, most preferably the sequence identity is at least 80% or 90 or 95 or 99%, or any integer from 40-100% sequence identity in ascending order. Similarly, polynucleotides having at least 40% sequence identity with a TAT-001 xenologue nucleotide, particularly potential orthologues (e.g., SEQ ID NO: 13, 14, 16, 17, 19, 20, 22, 23, 24, 26, 27, 29, 30, 31, 33, and 34) are considered substantially identical to the xenologue and useful in the methods of the invention.
“TAT-001 binding protein” refers to a molecule, multimer, composition, or complex that is, at least in part, peptidic, comprising at least 4 or more amino acids, that binds a TAT-001 polypeptide. Preferably, the TAT-001 binding protein binds the TAT-001 protein (SEQ ID NO: 5, or the close variant SEQ ID NO: 8), such as the denatured protein, but most preferably the native protein or its naturally modified forms. Preferably such binding is specific, and more preferably it is selective. Binding may occur anywhere on the TAT-001 molecule, including in discrete epitopes such as ones recognized in the TAT-001 peptide described herein as SEQ ID NO: 1 and/or SEQ ID NO: 3. “TAT-001 binding protein” may also refer to a collection of binding proteins such as a polyclonal antibody. A TAT-001 binding protein may be, for non-limiting example, an antibody, antibody-related peptide, one or more CDR regions of a TAT-001 binding antibody, or TAT-001 interacting protein.
“TAT-001 binding molecule” encompasses TAT-001 binding proteins, but also includes non-peptidic molecules and compositions including, but not limited to, those generally described as small molecules.
By “therapeutically effective immune response” is meant an immune response which is effective in treating a disease, particularly a neoplasm.
“Therapeutic moiety” refers to a moiety covalently or non-covalently bound to one or more macromolecules of interest, for example an antibody. Such binding may be direct or indirect, such as through a linker region. The moiety should have a known therapeutic effect, or potentially so, at the cellular, tissue, organ, systemic, or organismal level.
“Transcriptional regulatory elements” refers to nucleic acid sequences that regulate transcription. For example, not intended to be limiting, promoters, polyadenylation signals, start codons, and stop codons.
“Translational regulatory elements” refers to nucleic acid sequences that regulate translation. Non-limiting examples of translational regulatory elements include start codons, ribosome binding regions, polyadenylation signals, and stop codons.
“Transform” refers to the introduction of a polynucleotide (e.g., single or double stranded DNA, RNA, or a combination thereof) into a living cell by any means. Transformation may be accomplished by a variety of methods, including, but not limited to, electroporation, polyethylene glycol mediated uptake, particle bombardment, agrotransformation, and the like. This process may result in transient or stable expression of the transformed polynucleotide. By “stably transformed” is meant that the sequence of interest is integrated into a replicon in the cell, such as a chromosome or episome. Transformed cells encompass not only the end product of a transformation process, but also the progeny thereof which retain the polynucleotide of interest.
“Transgenic” refers to any cell, spore, tissue or part, or higher organism such as a plant or animal (for example, a mouse) that contains all or part of at least one recombinant polynucleotide. In many cases, all or part of the recombinant polynucleotide is stably integrated into a chromosome or stable extra-chromosomal element, so that it is passed on to successive generations.
“Treating” and “treatment” refer to reduction in severity, progression, spread, and/or frequency of symptoms, elimination of symptoms and/or underlying cause, prevention of the occurrence of symptoms and/or their underlying cause, and improvement or remediation of damage. “Treatment” is meant to include therapeutic treatment as well as prophylactic, or suppressive measures for the disease or disorder. Thus, for example, “treating” a patient involves prevention of a particular disorder or adverse physiological event in a susceptible individual as well as treatment of a clinically symptomatic individual by inhibiting or causing regression of a disorder or disease. The term “treatment” includes the administration of an agent prior to or following the onset of a disease or disorder thereby preventing or removing all signs of the disease or disorder. As another example, administration of the agent after clinical manifestation of the disease to combat the symptoms of the disease comprises “treatment” of the disease. Further, administration of the agent after onset and after clinical symptoms have developed where administration affects clinical parameters of the disease or disorder and perhaps amelioration of the disease, comprises “treatment” of the disease. The present method of “treating” a patient in need of anti-cancer therapy encompasses both prevention of a condition, disease, or disorder that is responsive to anti-cancer therapy and treatment of a condition, disease, or disorder that is responsive to anti-cancer therapy in a clinically symptomatic individual.
“Vaccine” refers to one or more immunogens that could be used to stimulate the production of antibodies, such as in inducing or enhancing an immune response to the immunogen that is effective in the prevention of disease, or in the treatment of disease associated with a pre-existing infection when administered to a patient. The immunogen(s) may be present in a variety of media including, but not limited to, serum or supernatant, or in purified form.
“Virus-based vector” refers to a recombinant agent for transferring genetic material, such as DNA or RNA, into a cell altered from one or more viruses or a prior altered version thereof. “Virus” generally refers to any of a large group of submicroscopic infective agents that are regarded either as extremely simple microorganisms or as extremely complex molecules, that typically contain a protein coat surrounding an RNA or DNA core of genetic material but no semi-permeable membrane, that are capable of growth and multiplication only in living cells, and that cause various diseases in humans, animals, or plants. Some, but not the only, examples are adenovirus, influenza, HIV, DNA tumor viruses, polio, and retroviruses. Exemplary vectors (not intended as limiting) may be found in Gene Transfer and Expression in Mammalian Cells Sawas C. Makrides (Ed.), Elsevier Science Ltd, 2003.
“Xenologue” refers to a homologous and/or analogous protein or amino acid sequence or a homologous and/or analogous nucleic acid sequence present in another species. Most commonly herein xenologue would refer to a non-human TAT-001 polypeptide or nucleic acid. Xenologues may be identified based on substantial sequence identity or via other methods, such as phenotypic screening for analogues. Preferably a xenologue is an analogue, related by function as may be assessable by complementation in a deficient or knockout model strain, and preferably it is homologous. Preferably it is a paralogue, one or more sequences from the other species that shares a direct common ancestor with a TAT-001 sequence, more preferably a paralogue related by both homology and function. Most preferably it is a likely orthologue, the corresponding gene in the other species sharing a direct common ancestor with a TAT-001 sequence, as may be evidenced by homology, analogy, synteny, and other models of evolutionary analysis. For some time after a speciation event this relationship is often easily inferred and cleanly defined since the two genes differ only modestly, however paralogues and orthologues can be difficult to distinguish as differences accumulate between the related sequences. Xenologues have uses in producing animal models such as transgenics and knockouts. They may also be used in screening efforts or efforts to produce binding molecules such as antibodies that take advantage of their sequence similarities, or, on occasion, their sequence differences, such as when screening for pan-species binding antibodies.
Discovery of TAT-001 and its Association with Cancer, and uses Therefrom
The present inventors have discovered two peptides, peptides #1 and #2 (SEQ ID NO: 1 and 3, respectively), overexpressed in tumor samples, which both uniquely match the amino acid sequence encoding the TAT-001 protein. Thus, increased expression of TAT-001 protein in human patients is associated with colon tumors as compared to adjacent normal tissue and that the overexpressed protein is in plasma membrane fractions (see Example 4). The present inventors have discovered that TAT-001 is associated with abnormal development and growth, and may be useful in further studying the mechanisms of cancer, and as a target for the identification of potential anti-cancer compounds, including antibodies for use in immunotherapy. Accordingly, the present invention provides methods for the identification of compounds that modulate TAT-001 (polypeptide or nucleic acid) expression or activity. These methods include contacting a candidate compound with a TAT-001 and detecting the presence or absence of binding between the compound and the TAT-001, or detecting a change in TAT-001 expression or activity. Methods are also included for the identification of active agents, such as small molecules or antibodies, which inhibit TAT-001 expression or activity. Such methods include administering a compound to a cell or cell population, and detecting a change in TAT-001 expression or activity. The methods and compositions of the invention are also useful for the identification of anti-cancer compounds.
Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices and materials are now described.
The cDNA/RNA (coding sequence SEQ ID NO: 6 and
It would be obvious to one of skill in the art to use sequences in the methods of the invention that differ from the TAT-001 sequences disclosed herein (e.g., SEQ ID NO. 5), but that have substantial similarity to a TAT-001 sequence, whether naturally occurring, produced through methods of mutagenesis, such as random mutagenesis, or engineered for various reasons. Preferably such sequences have substantial sequence identity to a TAT-001 sequence. Such sequences that are substantially similar or identical to a TAT-001 disclosed herein (e.g., SEQ ID NO. 5), or are derived from the same genetic locus or using a TAT-001 or fragment thereof as starting material, are considered compositions of the invention (TAT-001 polypeptides or TAT-001 polynucleotides as appropriate) and useful in the methods of the invention. Particularly preferred variant TAT-001 polypeptides or TAT-001 nucleotides are those derived from a cell with a cellular proliferative disease, such as a colon cancer.
Preferably such TAT-001 sequences also have one or more additional characteristics of a TAT-001 sequence, for example an activity analogous to that of a TAT-001 sequence. The degree of activity as compared to TAT-001 sequences disclosed herein (e.g., SEQ ID NO. 5) may vary with the intended use, and appropriate degrees of activity may be determined by one skilled in the art. In general, however, null alterations, sequences lacking a given activity or having diminishingly reduced activity with alterations (insertions, deletions, or substitutions) to the sequence as compared to the disclosed TAT-001 sequence (e.g., SEQ ID NO. 5), whether naturally occurring, produced through methods of mutagenesis, such as random mutagenesis, or engineered are desired. Null alterations may be useful as controls for the activity and delimiters of its likely range in TAT-001 protein. For non-null alterations, in general, it is preferable that the degree of activity be within three orders of magnitude of that of the TAT-001 sequences disclosed herein (e.g., SEQ ID NO. 5). More preferably the degree of activity non-null alterations will be within two orders of magnitude of that of the TAT-001 sequences disclosed herein (e.g., SEQ ID NO. 5). Most preferably the degree of activity non-null alterations will be within one order of magnitude of that of the TAT-001 sequences disclosed herein (e.g., SEQ ID NO. 5). It may also be preferable in some cases for a non-null alteration to be “super-active” and exceed the activity of the TAT-001 sequences disclosed herein (e.g., SEQ ID NO. 5) by 4, 5, 6, or more orders of magnitude.
The activity to be measured for comparison or screened for among a library of TAT-001s, such as a library of mutagenized sequences, may be any activity relevant to use in the methods of the invention, such as a characteristic of a TAT-001 that will be as a variable in, or a criterion for, assessing the outcome of a screening method. For example, apoptotic activity of various sequences may be assayed by methods known in the art or herein, and the determined activity may be used as a criterion for selecting sequences for use in an assay of TAT-001 apoptotic function under different conditions. Thus, extending the example, a TAT-001 murine orthologue that is more readily expressed and purified than its human counterpart may be mutagenized to produce a super-active version and a null version relative to a TAT-001's enzymatic activity, which is generally too low to measure readily, yet critical to its finction. The sequences may then be used to screen for compounds that inhibit the now measurable enzymatic activity relative to the null control, and the candidate compounds thus identified may them be subjected to further screening efforts to find a compound appropriate for use in mice or humans. A preferred activity for comparison is immunogenicity.
One of skill in the art should be able to determine the lengths of TAT-001 and candidate TAT-001 sequences appropriate for comparison. For example, in comparing a potentially orthologous protein to a TAT-001 it may be appropriate to compare them over their full lengths, however if the candidate TAT-001 protein appears to have undergone gene fusion and correspond to TAT-001 plus some other gene product, or is a recombinant fusion protein, it may be appropriate to only compare the portion corresponding to TAT-001 sequence for determining the % sequence similarity and/or identity. This can be accomplished using by bl2seq in an initial comparison of the two sequences to determine the corresponding section of the candidate sequence and restricting a second BLAST to that section. bl2seq will itself occasionally limit the length over which the comparison occurs to less than full length, such as through a dropoff calculation that leaves several amino acids out of the comparison at a protein's N- and C-termini despite the two proteins being compared having the same length. In such cases it is preferred that the % similarity or % identity is at least in part over the portion relevant to the use at hand (e.g., over the kinase domain for a fragment to be used in a kinase assay), but is preferably over at least about 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, or 99% of the full length protein. And, it is also preferred that sequences such as that described that are excluded by dropoff, particularly start and stop codons, etc. still be considered part of the TAT-001 sequence of the invention. For short peptides (e.g., 3 to 50 amino acids), such as those used as therapeutic peptides or antigen peptides it may be more appropriate to rely more heavily on the activity than on the percent sequence similarity or identity for determining whether the peptide falls within the scope of the invention. In other words, a ten amino acid peptide with only four residues identical to the corresponding length fragment of TAT-001 that is useful in generating high affinity anti-TAT-001 antibodies might still be considered enough of a structural equivalent to a TAT-001 fragment based on the antibody binding to be considered a composition of the invention despite 40% identity being below the preferred cut-off. This may also be true for longer sequences that contain an accessible, constrained, concatamer of a TAT-001 fragment or binding motif or epitope, such as a concatamer of a tripeptide TAT-001 epitope's use as an antigen. Such exceptions may be determined by one skilled in the art.
Thus, point mutations, polymorphisms, splice variants, mutagenized sequences, transcription and/or translation optimized sequences, recombinant variants, modifications, derivatives, fusions, fragments, homologues, and combinations thereof that constitute TAT-001 sequences of the invention can be determined through percent sequence similarity, or preferably percent sequence identity, to a TAT-001 sequence disclosed herein (e.g., SEQ ID NO. 5), or through knowledge of the sequence's origin in a TAT-001 genetic locus or origin in a process deriving it from a TAT-001 sequence. And, preferably such sequences exhibit one or more activities of a TAT-001.
Nucleic Acids
Nucleic acids of the invention have a variety of uses, including, but not limited to, detecting and quantitating TAT-001 gene expression for diagnostic and prognostic purposes; expressing TAT-001 polypeptides; screening for modulators of TAT-001 expression, therapeutic applications such as anti-sense vectors or ribozymes; and for producing transgenic or knockout animal model systems for drug screening and testing. TAT-001 nucleic acid sequences can be initially identified by substantial nucleic acid sequence identity to the TAT-001 nucleic acid sequences described herein (e.g., SEQ ID NO: 2, 4, 6, and 9) or by their encoding a protein of substantial amino acid sequence identity to the TAT-001 polypeptide sequences described herein (e.g., SEQ ID NO: 1, 3, 5, and 8). Such homology can be based on the overall nucleic acid or amino acid sequence, and is generally determined as outlined below, using an assessment of homology, such as, for example, may be provided by sequence alignment software, such as a BLAST program (Basic Local Alignment Search Tool; (Altschul et al. (1990) J Mol Biol 215: 403-410), NCBI BLAST2.0 software as defmed by Altschul et al. (1997) Nucleic Acids Res. 25: 3389-3402, using Smith Waterman Aligrinment (Smith and Waterman (1981) J Mol Biol 147: 195-197) as incorporated into GeneMatcher Plus™, or, preferably bl2seq (Tatusova and Madden (1999) FEMS Microbiol Lett. 174: 247-250), or through nucleic acid hybridization conditions.
TAT-001 nucleic acids also include polynucleotides comprising TAT-001 regulatory and structural nucleic acid sequences or fragments thereof, including TAT-001 genomic sequence (e.g., SEQ ID NO: 10), introns, niRNA untranslated regions, and promoters, and nucleic acids with substantial nucleic acid sequence identity thereto. Such nucleic acid sequences are useful, for example, for generating knockout and transgenic animal models, or for screening for modulators of TAT-001 expression. TAT-001 nucleic acids also include transcription and translation optimized sequences, such as those produced through codon optimization and IRES (internal ribosomal entry site) incorporation, or tandem or concatameric sequences, which may be useful for example in expressing and purifying the protein.
TAT-001 nucleic acids may be fragments of more extensive TAT-001 nucleic acids including polynucleotides encoding fragments of TAT-001 polypeptides (e.g., SEQ ID NO: 2 and 4). Encoding polynucleotides may include non-coding sequences (e.g., SEQ ID NO: 7 and 10) and may be of as few as 10 contiguous nucleotides. They may encode TAT-001 polypeptide fragments comprising 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or more than 25 contiguous amino acids; at least 30, 35, 40, 45, 50, 55, 60, 65, 70, 80, 85, 90,95,100,105,110,115,120,125,130,135,140,145,150,155,160,165, 170,175, 180,185, or more than 190 contiguous amino acids of a TAT-001 polypeptide. Such fragments may be used, for example, as primers for PCR, as probes in hybridization, in screening for binders to the nucleic acid or modulators of its expression, or in expressing peptidic fragments of TAT-001, etc.
The invention further provides for TAT-001 nucleic acids comprising polynucleotides substantially complementary to all or part of the TAT-001 nucleic acids, for example an anti-sense fragment complementary to bases 26-78 of the TAT-001 MRNA coding sequence (SEQ ID NO: 6). Thus, for example, both strands of a double stranded nucleic acid molecule are included in the present invention (whether or not they are associated with one another), such as dual strands of DNA, but also including double-stranded RNA, and DNA/RNA hybrids. Also included are mRNA molecules and complementary DNA molecules (e.g., cDNA molecules). Substantially complementary sequences should be complementary enough to hybridize to the corresponding TAT-001 nucleic acid under normal reaction conditions, particularly high, or moderate stringency hybridization conditions. A variety of hybridization conditions may be used in the present invention, including high, moderate and low stringency conditions. Stringency can be controlled by altering a step parameter that is a thermodynamic variable, including, but not limited to, temperature, formamide concentration, salt concentration, chaotropic salt concentration pH, organic solvent concentration, etc. High stringency conditions are known in the art; see for example Maniatis et al. Molecular Cloning: A Laboratory Manual, 2nd Edition (1989), and Short Protocols in Molecular Biology, ed. Ausubel, et aL, (1989) both of which are hereby incorporated by reference. Stringent conditions are sequence-dependent and will be different in different circumstances. Longer sequences hybridize specifically at higher temperatures. An extensive guide to the hybridization of nucleic acids is found in Tijssen, Techniques in Biochemistry and Molecular Biology—Hybridization with Nucleic Acid Probes, “Overview of principles of hybridization and the strategy of nucleic acid assays” (1993). Generally, stringent conditions are selected to be about 5-10° C. lower than the thermal melting point (Tm) for the specific sequence at a defmed ionic strength pH. The Tm is the temperature (under defined ionic strength, pH and nucleic acid concentration) at which 50% of the probes complementary to the target hybridize to the target sequence at equilibrium (as the target sequences are present in excess, at Tm, 50% of the probes are occupied at equilibrium). Stringent conditions will be those in which the salt concentration is less than about 1.0 M sodium ion, typically about 0.01 to 1.0 M sodium ion concentration (or other salts) at pH 7.0 to 8.3 and the temperature is at least about 3020 C. for short probes (e.g., 10 to 50 nucleotides) and at least about 60° C. for long probes (e.g., greater than 50 nucleotides). Stringent conditions may also be achieved with the addition of destabilizing agents such as formamide. Moderate or low stringency conditions may also be used, as are known in the art; see Maniatis and Ausubel, supra, and Tijssen, supra. Complementary nucleic acids may be useful as probes in hybridization, in vectors comprising double-stranded DNA molecules, or in modulating TAT-001 expression through use of anti-sense, RNAi, or ribozymes, etc.
Additional TAT-001 nucleic acids, including homologues, paralogues, and orthologues from species other than human, may be obtained using standard cloning techniques, screening techniques, or homology search techniques. For example, a cDNA library derived from mRNA in murine cells, using expressed sequence tag (EST) analysis (Adams et al. (1991) Science 252: 1651-1656; Adams et al. (1992) Nature 355: 632-634; Adams et al. (1995) Nature 3 77: (6547 Suppl): 3-174) could be probed by BLAST homology search ((Altschul et al. (1997) Nucleic Acids Res. 25: 3389-3402; Altschul et al. (1990) J Mol Biol. 215: 403-410)) to identify TAT-001 homologues. Alternatively, a murine cDNA library might be screened using a human TAT-001 cDNA under low stringency conditions. Additional TAT-001 nucleic acids may also be obtained from natural sources such as genomic DNA libraries or can be synthesized using well known and commercially available techniques. TAT-001 nucleic acids identified as xenologues include those from Pan troglodytes (GenBank GI: 55634139; SEQ ID NO: 29 and the coding sequence—SEQ ID NO: 30), Mus musculus (GenBank GIs: 48597001, 12856631, 12849896, 13097453; SEQ ID NO: 14, 17, 20, and 23, respectively, and the coding sequences SEQ ID NO: 13, 16, 19, and 22), Rattus norveticus (GenBank GI: 34862850; SEQ ID NO: 26), and Gallus Gallus (GenBank GI: 50749572; SEQ ID NO: 33), as well as their corresponding genomic sequences (SEQ ID NO: 31, 24, 27, and 34, for chimpanzee, mouse, rat, and chicken, respectively).
One skilled in the art will understand that, in many cases, an isolated cDNA sequence will be incomplete, in that the region coding for the polypeptide is cut short at the 5′ end of the cDNA. This is often a consequence of reverse transcriptase, an enzyme with inherently low processivity (a measure of the ability of the enzyme to remain attached to the template during the polymerization reaction), failing to complete a DNA copy of the MRNA template during 1st strand cDNA synthesis. Using the sequences provided herein, additional TAT-001 nucleic acid sequences may be obtained by using techniques well known in the art for either extending sequences or obtaining full length sequences (see Maniatis et al., and Ausubel, et al., supra), for example, RACE (Rapid amplification of cDNA ends; e.g., Frohman et al. (1988) Proc Natl Acad Sci U.S.A. 85: 8998-9002). Recent modifications of the RACE technique (exemplified by the MarathonT Technology of Clontech Laboratories Inc.) have significantly simplified the search for longer cDNAs. This technology uses cDNAs prepared from MRNA extracted from a chosen tissue followed by the ligation of an adaptor sequence onto each end. PCR is then carried out to amplify the missing 5′ end of the cDNA using a combination of gene specific and adaptor specific oligonucleotide primers. The PCR reaction is then repeated using nested primers which have been designed to anneal with the amplified product, typically an adaptor specific primer that anneals further 3′ in the adaptor sequence and a gene specific primer that anneals further 5′ in the known gene sequence. The products of this reaction can then be analyzed by DNA sequencing and a full length cDNA constructed either by joining the product directly to the existing cDNA to give a complete sequence, or carrying out a separate full length PCR using the new sequence information for the design of the 5′ primer.
Indeed, PCR techniques may be used to amplify any desired TAT-001 nucleic acid sequence. Thus the sequence data for TAT-001 nucleic acids, such as is provided herein, can be used to design primers for use in PCR so that a desired TAT-001 sequence can be targeted and then amplified to a high degree. Typically, primers will be at least five nucleotides long and will generally be at least ten nucleotides long (e.g., fifteen to twenty-five nucleotides long). In some cases, primers of at least thirty or at least thirty-five nucleotides in length may be used. As a further alternative, chemical synthesis which may be automated may be used. Relatively short sequences may be chemically synthesized and ligated together to provide a longer sequence.
Unless the context indicates otherwise, TAT-001 nucleic acid molecules may have one or more of the following characteristics: 1) they may be DNA or RNA; 2) they may be single or double stranded; 3) they may be provided in recombinant form, e.g., covalently linked to a 5′ and/or a 3′ flanking sequence to provide a molecule which does not occur in nature; 4) they may be provided without 5′ and/or 3′ flanking sequences which normally occur in nature; 5) they may be provided in substantially pure form. Thus, they may be provided in a form which is substantially free from contaminating proteins or other nucleic acids; and 6) they may be provided with or without introns (e.g., as cDNA). The nucleic acid molecule may be in recombinant or chemically synthetic form. Preferably, the nucleic acid is in isolated form.
Manipulation of the nucleic acid encoding a TAT-001 polypeptide can be used to produce both modified proteins and for generating large quantities of protein for purification purposes. TAT-001 polypeptide derivatives can be created by introducing one or more nucleotide substitutions, additions or deletions into the nucleotide sequence of a TAT-001 nucleic acid such that one or more amino acid substitutions, additions or deletions are introduced into the encoded protein. Standard techniques known to those of skill in the art can be used to introduce mutations, including, for example, site-directed mutagenesis and PCR-mediated mutagenesis. Preferably, conservative amino acid substitutions are made at one or more predicted non-essential amino acid residues. Random mutagenesis may even be used to produce a library of modified TAT-001 proteins (see for example Xu et aL. (1999) Biotechniques 27: 1102-4, 1106, 1108; Lin-Goerke et al. (1997) Biotechniques 23: 409-412; Fromant et al. (1995) Anal Biochem. 224: 347-53; Fujii et al. (2004) Nucleic Acids Res. 32(19): el45; Chusacultanachai and Yuthavong (2004) Methods Mol Biol. 270: 319-34).
Vectors
The invention also relates to recombinant vectors, such as recombinant vectors, which include one or more TAT-001 nucleic acids (e.g., SEQ ID NO: 11), as well as host cells containing the vectors or which are otherwise engineered to contain or express TAT-001 nucleic acids or polypeptides, and methods of making such vectors and host cells and their use in production of TAT-001 polypeptides by recombinant or synthetic techniques.
In one embodiment, the polynucleotides of the invention are joined to a vector (e.g., a cloning or expression vector (e.g., SEQ ID NO: 11)). The vector may be, for example, a phage, plasmid, or viral vector. Viral vectors may be replication competent or replication defective. (For a list of preferred viral vectors for expression of the TAT-001 nucleic acid see those listed below under the section Gene Therapy). In the latter case, viral propagation generally will occur only in complementing host cells. The polynucleotides may be joined to a vector containing a selectable marker for propagation in a host. Introduction of the vector construct into the host cell can be effected by techniques known in the art which include, but are not limited to, calcium phosphate transfection, DEAE-dextran mediated transfection, cationic lipid-mediated transfection, electroporation, transduction, infection or other methods. Such methods are described in many standard laboratory manuals, such as Davis et al. (1986) Basic Methods In Molecular Biology.
i.) Expression Vectors
TAT-001 nucleic acids that include sequences encoding TAT-001 polypeptides can be used for the recombinant production of the TAT-001 polypeptides. The TAT-001 nucleic acids may include the coding sequence for the mature polypeptide alone, or the coding sequence for the mature polypeptide in reading frame with other coding sequences, such as those encoding a leader or secretory sequence, a pre-, pro-or prepro-protein sequence, a cleavable sequence (e.g., the cleavable GST fusion encoded in SEQ ID NO: 11) or other fusion peptide portions, such as an affinity tag or an additional sequence conferring stability during production of the polypeptide. Preferred affinity tags include, but are not limited to, multiple histidine residues (for example see Gentz et al. (1989) Proc Natl Acad Sci U.S.A. 86: 821-824), a FLAG tag, HA tag, or myc tag. The TAT-001 nucleic acids may also contain non-coding 5′ and 3′ sequences, such as transcribed, non-translated sequences, splicing and polyadenylation signals, ribosome binding sites and sequences that stabilize mRNA. The TAT-001 polypeptides may be produced by culturing a host cell transformed with an expression vector containing a TAT-001 nucleic acid encoding a TAT-001 polypeptide under the appropriate conditions to induce or cause expression of the TAT-001 polypeptide. The conditions appropriate for TAT-001 polypeptide expression will vary with the choice of the expression vector and the host cell and may be easily ascertained by one skilled in the art through routine experimentation. For example, the use of constitutive promoters in the expression vector will require optimizing the growth and proliferation of the host cell, while the use of an inducible promoter requires the appropriate growth conditions for induction. In addition, in some embodiments, the timing of the harvest of the polypeptide from the host cell is important (e.g., the baculoviral systems used in insect cell expression are lytic viruses, and thus harvest time selection can be crucial for product yield).
Generally, recombinant expression vectors will include origins of replication and selectable markers permitting transformation of the host cell, e.g., the ampicillin resistance gene of E. coli and S. cerevisiae TRP1 gene, and a promoter derived from a highly-expressed gene to direct transcription of a downstream structural sequence. Such promoters can be derived from operons encoding glycolytic enzymes such as 3-phosphoglycerate kinase (PGK), α-factor, acid phosphatase, or heat shock proteins, among others. The heterologous structural sequence is assembled in appropriate phase with translation initiation and termination sequences, and preferably, a leader sequence capable of directing secretion of translated protein into the periplasmic space or extracellular medium. Optionally, the heterologous sequence can encode a fusion protein including an N-terminal identification peptide (tag) imparting desired characteristics, for example, stabilization or simplified purification of expressed recombinant product. In general, the transcriptional and translational regulatory sequences may include, but are not limited to, promoter sequences, ribosomal binding sites, transcriptional start and stop sequences, translational start and stop sequences, and enhancer or activator sequences. In a preferred embodiment, the regulatory sequences include a promoter and transcriptional start and stop sequences.
In addition, the expression vector may comprise additional elements. For example, the expression vector may have two replication systems, thus allowing it to be maintained in two organisms, for example in mammalian or insect cells for expression and in a procaryotic host for cloning and amplification. In another example, the vector is an integrating expression vector in which the expression vector contains at least one sequence homologous to the host cell genome, and preferably two homologous sequences which flank the expression construct. The integrating expression vector may be directed to a specific locus in the host cell by selecting the appropriate homologous sequence for inclusion in the vector. Constructs for integrating expression vectors are well known in the art.
In one embodiment, the DNA of the invention is operatively associated with an appropriate heterologous regulatory element (e.g., promoter or enhancer), such as, the phage lambda PL promoter, the E. coli lac, trp, phoA, and tac promoters, the SV40 early and late promoters and promoters of retroviral LTRs. Promoter sequences generally encode either constitutive or inducible promoters. The promoters may be either naturally occurring promoters or hybrid promoters, with a combination of elements from more than one promoter. Other suitable promoters will be known to the skilled artisan.
As indicated, the expression vectors will preferably include at least one selectable marker (e.g., dihydrofolate reductase, G418, or neomycin resistance for eukaryotic cell culture and tetracycline, kanamycin, or ampicillin resistance genes for culturing in E. coli and other bacterial cells).
Useful expression vectors for bacterial use are constructed by inserting a structural DNA sequence encoding a desired protein together with suitable translation initiation and termination signals in operable reading phase with a finctional promoter. The vector will comprise one or more phenotypic selectable markers and an origin of replication to ensure maintenance of the vector and to, if desirable, provide amplification within the host. For example, useful expression vectors for bacterial use can comprise a selectable marker and bacterial origin of replication derived from commercially available plasmids comprising genetic elements of the well-known cloning vector pBR322 (ATCC 37017). Such commercial vectors include, for example, pKK223-3 (Pharmacia Fine Chemicals, Uppsala, Sweden) and GEM1 (Promega Biotec, Madison, Wis., USA). These pBR322 “backbone” sections are combined with an appropriate promoter and the structural sequence to be expressed. Among vectors preferred for use in bacteria include pHE4-5 (ATCC Accession No. 209311; and variations thereof), pQE70, pQE60 and pQE-9, available from QIAGEN, Inc., supra; pBS vectors, Phagescript vectors, Bluescript vectors, pNH8A, pNH16a, pNH18A, pNH46A, available from Stratagene; and ptrc99a, pKK223-3, pKK233-3, pDR540, pRIT5 available from Pharmacia. Preferred expression vectors for use in yeast systems include, but are not limited to, pYES2, pYD1, pTEF1/Zeo, pYES2/GS, pPICZ, pGAPZ, pGAPZalpha, pPIC9, pPIC3.5, pHIL-D2, pHIL-S1, pPIC3.5K, pPIC9K, and PAO815 (all available from Invitrogen, Carlsbad, Calif.). Among preferred eukaryotic vectors are pWLNEO, pSV2CAT, pOG44, pXT1 and pSG available from Stratagene, and pSVK3, pBPV, pMSG and pSVL (available from Pharmacia). Other suitable vectors will be readily apparent to the skilled artisan.
ii.) Other Vectors
TAT-001 nucleic acids may also be used in other vectors known in the art including but not limited to vectors for producing gene disruptions (“knockouts”), other transgenic modifications (“knockins”), anti-sense vectors, RNAi vectors, gene therapy vectors, and vectors for assessing or utilizing TAT-001 promoter activity.
TAT-001 nucleic acids and vectors comprising TAT-001 may also be used for screening compounds for candidate agents that can modulate TAT-001 expression. For example, a library of mammalian transcription factors can be screened against a vector containing the TAT-001 promoter operably linked to a reporter gene sequence to determine transcription factors capable of modulating expression from the TAT-001 promoter. For example, a yeast one-hybrid system (Clontech, Palo Alto, Calif.) (Wang and Reed (1993) Nature 364: 121-126; Strubin et al. (1995) Cell 80: 497-506; Lehming et al. (1994) Nature 371: 175-179; Li et al. (1993) Science 262: 1870-1873; Luo et al. (1996) Biotechniques. 20: 564-568; Gstaiger et al. (1995) Nature 373: 360-362) or variations thereupon may be used to isolate transcription factors binding the TAT-001 promoter, or, for example, a CAT reporter system may be used to assess small molecule impact on expression from the TAT-001 promoter.
iii.) Host Cells
Host cells useful for the expression of TAT-001 nucleic acids can be a higher eukaryotic cell, such as a mammalian cell (e.g., a human derived cell), or a lower eukaryotic cell, such as a yeast cell, or the host cell can be a prokaryotic cell, such as a bacterial cell. Examples of appropriate hosts include, but are not limited to, bacterial cells, such as E. coli, Bacillis subtilis, Salmonella typhimurium, and various species within the genera Pseudomonas, Streptomyces, and Staphylococcus); archaebacteria; fungal cells, such as yeast cells (e.g., Saccharomyces cerevisiae or Pichia pastoris (ATCC Accession No. 201178)); insect cells such as Drosophila S2 and Spodoptera Sf9 cells; animal cells such as CHO, COS, 293, C129 cells, Neurospora, BHK, HeLa cells, THP1 cell line (a macrophage cell line), Bowes melanoma cells, and human cells and cell lines; and plant cells. Appropriate culture mediums and conditions for the above-described host cells are known in the art.
The host strain may be one which modulates the expression of the inserted gene sequences, or modifies and processes the gene product in the specific fashion desired. Expression from certain promoters can be elevated in the presence of certain inducers; thus, expression of the genetically engineered polypeptide may be controlled. Furthermore, different host cells have characteristics and specific mechanisms for the translational and post-translational processing and modification (e.g., phosphorsylation and cleavage) of proteins. Appropriate cell lines can be chosen to ensure the desired modifications and processing of the foreign protein expressed. Selection of appropriate vectors and promoters for expression in a host cell is a well-known procedure and the requisite techniques for expression vector construction, introduction of the vector into the host, and expression in the host are routine skills in the art.
Following transformation of a suitable host strain and growth of the host strain to an appropriate cell density, the selected promoter is induced by appropriate means (e.g., temperature shift or chemical induction) if necessary or desired, and cells are cultured for an additional period. Cells are typically harvested by centrifugation, disrupted by physical or chemical means, and the resulting crude extract retained for further purification.
Host cells employed in expression of proteins can be disrupted by any convenient method, including freeze-thaw cycling, sonication, mechanical disruption, or use of cell lysing agents. Such methods are well known to those skilled in the art.
Therapeutic Nucleic Acids
Symptoms of cancer may be ameliorated by decreasing the level or activity of a TAT-001 polypeptide or nucleic acid by using TAT-001 nucleic acid sequences as defmed herein in conjunction with well-known gene “knock-out,” anti-sense, RNAi, ribozyme, or triple helix methods to decrease gene expression. In this approach, ribozyme or triple helix molecules are used to modulate the activity, expression or synthesis of the gene, and thus to ameliorate the symptoms of cancer. Such molecules may be designed to reduce or inhibit expression of a mutant or non-mutant target gene. Such techniques are well known to those of skill in the art.
i.) Anti-sense and RNAi
The invention also provides for the use of at least one TAT-001 nucleic acid in the preparation of a pharmaceutical composition for use in the treatment of cancer, preferably a colon cancer or metastases therefrom. In a specific embodiment, TAT-001 nucleic acid molecules are used as anti-sense molecules or as molecules for RNA interference (RNAi), to alter the expression of TAT-001 polypeptides by binding to and/or triggering the destruction of TAT-001 nucleic acids and thus may be used in the treatment or prevention of cancer. Anti-sense nucleic acids of the invention include TAT-001 nucleic acids capable of hybridizing through sequence complementary to a portion of a TAT-001 RNA, preferably a TAT-001 mRNA encoding a TAT-001 polypeptide. The anti-sense nucleic acid can be complementary to a coding and/or non-coding region of an mRNA encoding such a polypeptide. Most preferably, expression of a TAT-001 nucleic acid or polypeptide or both is inhibited by use of anti-sense nucleic acids. Complementary to a nucleotide sequence in the context of antisense oligonucleotides and methods therefore means sufficiently complementary to such a sequence as to allow hybridization to that sequence in a cell, i.e., under physiological conditions. Preferably such sequences are at least 40% complementary to a TAT-001 nucleic acid, or at least 50%, or at least 60%, more preferably the percent complementarity is at least 70%, most preferably the percent complementarity is at least 80% or 90 or 95 or 99% complementary to a TAT-002 nucleic acid, or any integer value from 40-100% complementarity in ascending order. Antisense oligonucleotides preferably comprise a sequence containing from about 8 to about 100 nucleotides, more preferably the antisense oligonucleotides comprise from about 15 to about 30 nucleotides. Antisense oligonucleotides can also contain a variety of modifications for example, modified intemucleoside lineages (Uhlmann and Peyman (1990) Chemical Reviews 90: 543-548; Schneider and Banner (1990) Tetrahedron Lett. 31: 335); modified nucleic acid bases as disclosed in U.S. Pat. No. 5,958,773 and patents disclosed therein; and/or sugars and the like. Preferred modifications are those that confer resistance to nucleolytic degradation.
Any modifications or variations of the antisense molecule which are known in the art to be broadly applicable to antisense technology are included within the scope of the invention. Such modifications include preparation of phosphorus-containing linkages as disclosed in U.S. Pat. Nos. 5,536,821; 5,541,306; 5,550,111; 5,563,253; 5,571,799; 5,587,361, 5,625,050, and 5,958,773. Modifications can include natural and non-natural oligonucleotides, both modified (e.g., phosphorothiates, phosphorodithiates, and phosphotriesters) and unmodified, oligonucleotides with modified (e.g., morpholino linkages and heteroatom backbones) or unmodified backbones, as well as oligonucleotide mimetics such as Protein Nucleic Acids, locked nucleic acids, and arabinonucleic acids. Numerous nucleobases and linkage groups may be employed in the nucleobase oligomers of the invention, including those described in U.S. Patent Application Nos. 20030114412 and 20030114407, incorporated herein by reference.
The antisense compounds of the invention can include modified bases. The antisense oligonucleotides of the invention can also be modified by chemically linking the oligonucleotide to one or more moieties or conjugates to enhance the activity, cellular distribution, or cellular uptake of the antisense oligonucleotide. Such moieties or conjugates include lipids such as cholesterol, cholic acid, thioether, aliphatic chains, phospholipids, polyamines, polyethylene glycol (PEG), palmityl moieties, and others as disclosed in, for example, U.S. Pat. Nos. 5,514,758; 5,565,552; 5,567,810; 5,574,142; 5,585,481; 5,587,371; 5,597,696 and 5,958,773.
Chimeric antisense oligonucleotides are also within the scope of the invention, and can be prepared from the present inventive oligonucleotides using the methods described in, for example, U.S. Pat. Nos. 5,013,830; 5,149,797; 5,403,711; 5,491,133; 5,565,350; 5,652,355; 5,700,922 and 5,958,773.
In the antisense art a certain degree of routine experimentation is required to select optimal antisense molecules for particular targets. To be effective, the antisense molecule preferably is targeted to an accessible, or exposed, portion of the target RNA molecule. Although in some cases information is available about the structure of target MRNA molecules, the current approach to inhibition using antisense is via experimentation. MRNA levels in the cell can be measured routinely in treated and control cells by reverse transcription of the MRNA and assaying the cDNA levels. The biological effect can be determined routinely by measuring cell growth or viability as is known in the art.
Measuring the specificity of antisense activity by assaying and analyzing cDNA levels is an art-recognized method of validating antisense results. It has been suggested that RNA from treated and control cells should be reverse-transcribed and the resulting cDNA populations analyzed (Branch (1998) Trends Biochem Sci. 23: 45-50).
The invention further embraces the use of interfering RNA (RNAI) to disrupt TAT-001 expression. This can be accomplished by various means. For example, in one method all or a portion of the targeted gene can be incorporated into a vector and used to target desired cells, e.g., colon cancer cells. RNAI can be used to collectively refer to several gene silencing techniques, including the use of siRNA (short interfering RNAs), shRNA (short hairpin RNA—an RNA bearing a fold-back stem-loop structure), dsRNA (double-stranded RNA, itself on occasion used to encompass any double-stranded RNA, but also used in this section to discuss double-stranded RNAs of greater length than, for instance, siRNAs as a class, in particular because longer double-stranded RNAs are more likely to activate non-specific host responses to double-stranded RNA (see, for example, Williams (1997) Biochem Soc Trans. 25: 509-513; Gil and Esteban (2000) Apoptosis 5: 107-114; Clarke and Mathews (1995) RNA. 1: 7-20; Baglioni and Nilsen (1983) Interferon. 5: 23-42)), miRNA (micro RNAs), stRNAs (short (or “small”) temporal RNAs), and the like.
RNA interference is a mechanism to suppress gene expression in a sequence specific manner. See, for example, Brumelkamp et aL. (2002) Sciencexpress (Mar. 21, 2002); Sharp (1999) Genes Dev. 13: 139-141; and Cathew (2001) Curr Op Cell Biol. 13: 244-248; Zamore et aL. (2000) Cell 101: 25-33; Bass (2001) Nature 411: 428-429; Elbashir et aL. (2001) Nature 411: 494-498; PCT Publication Nos. WO 00/44895; WO 01/36646; WO 99/32619; WO 00/01846; WO 01/29058; WO 99/07409; and WO 00/44914; Allshire (2002) Science 297:1818-1819; Volpe et al. (2002) Science 297: 1833-1837; Jenuwein (2002) Science 297: 2215-2218; and Hall et aL. (2002) Science 297: 2232-2237; Hutvagner and Zamore (2002) Science 297: 2056-60; McManus et aL. (2002) RNA. 8: 842-850; Reinhart et aL. (2002) Genes Dev. 16: 1616-1626; and Reinhart and Bartel (2002) Science 297: 1831.
In certain embodiments of the invention, TAT-001 nucleic acids can be, or will be used as guide sequences to produce, RNAi molecules of the invention which comprise sense and antisense sequences or regions, wherein the sense and antisense regions are generally covalently linked by nucleotide or non-nucleotide linker molecules as is known in the art, or are alternately non-covalently linked by ionic interactions, hydrogen bonding, van der waals interactions, hydrophobic intercations, and/or stacking interactions. In mammalian cells, short, e.g., 21 nt, double stranded small interfering RNAs (siRNA) have been shown to be effective at inducing an RNAI response. See, e.g., Elbashir et aL. (2001) Nature 411: 494-498. The mechanism may be used to downregulate expression levels of identified genes, e.g., treatment of or validation of relevance to disease. siRNAs are preferably between 19 and 29 nucleotides in length, most preferably between 21 and 25 nucleotides in length. By comparison dsRNAs can be considered to be at least 30 nucleotides in length, at least 50 nucleotides in length, at least 100 nucleotides in length, at least 500 nucleotides in length. shRNAs preferably form double-stranded regions of 19 to 29 nucleotides in length, preferably 22 to 29 nucleotides in length, more preferably 25 to 29 nucleotides in length, most prefearbly 29 nucleotides in length (see Paddison et al. (2002) Genes Dev. 16: 948-58).
RNAi has been studied in a variety of systems, and a number of methods for producing and selecting RNAi molecules, such as shRNAs, siRNAs, and dsRNAs. Some methods for this embodiment of the invention are reviewed or documented in Paddison et al. (2004) Methods Mol Biol. 265: 85-100; Kakare et al. (2004) Appl Biochem Biotechnol. 119: 1-12; Paddison et al. (2004) Nature 428: 427-31; Paddison and Hannon (2002) Cancer Cell 2: 17-23; Paddison et al. (2002) Genes Dev. 16: 948-958; Hannon and Conklin (2004) Methods Mol Biol. 257: 255-266; Katoh et al. (2003) Nucleic Acids Res Suppl. (3): 249-250; Koper-Emde et al. (2004) Biol Chem. 385: 791-794; Gupta et al. (2004) Proc Natl Acad Sci U.S.A. 101: 1927-1932; Paddison et al. (2002) Proc Natl Acad Sci U.S.A. 99: 1443-1448 and the references thereto, and kits for some vectors are available (e.g. GeneEraser™ (catalog #240090) from Stratagene, La Jolla, Calif.). Fire et al. ((1998) Nature 391: 806-811) were the first to observe RNAI in C. elegans. Wianny and Goetz ((1999) Nature Cell Biol. 2: 70-75) describe RNAi mediated by dsRNA in mouse embryos. Hammond et al. ((2000) Nature 404: 293-296) describe RNAi in Drosophila cells transfected with dsRNA. Elbashir et al. ((2001) Nature 411: 494-498) describe RNAi induced by introduction of duplexes of synthetic 21-nucleotide RNAs in cultured mammalian cells including human embryonic kidney and HeLa cells. Work in Drosophila embryonic lysates revealed certain requirements for siRNA length, structure, chemical composition, and sequence that are essential to mediate efficient RNAI activity. These studies have shown that 21 nucleotide siRNA duplexes are most active when containing two 2-nucleotide 3′-terminal nucleotide overhangs. Furthermore, substitution of one or both siRNA strands with 2′-deoxy or 2′-O-methyl nucleotides abolishes RNAi activity, whereas substitution of 3′-terminal siRNA nucleotides with deoxy nucleotides was shown to be tolerated. Mismatch sequences in the center of the siRNA duplex were also shown to abolish RNAi activity. In addition, these studies also indicate that the position of the cleavage site in the target RNA is defmed by the 5′-end of the siRNA guide sequence rather than the 3′-end (Elbashir et al. (2001) EMBO J. 20: 6877-6888). Other studies have indicated that a 5′-phosphate on the target-complementary strand of a siRNA duplex is required for siRNA activity and that ATP is utilized to maintain the 5′-phosphate moiety on the siRNA (Nykanen et al. (2001) Cell 107: 309-321); however, siRNA molecules lacking a 5′-phosphate are active when introduced exogenously, suggesting that 5′-phosphorylation of siRNA constructs may occur in vivo.
RNAi molecules include any form of RNA such as partially purified RNA, essentially pure RNA, synthetic RNA, recombinantly produced RNA, as well as altered RNA that differs from naturally occurring RNA by the addition, deletion, substitution, and/or alteration of one or more nucleotides. Such alterations can include the addition of non-nucleotide material, such as to the end(s) of the 21 to 23 nucleotide RNA or internally (at one or more nucleotides of the RNA). In a preferred embodiment, the RNA molecule contains a 3′ hydroxyl group. Nucleotides in the RNAi molecules of the present invention can also comprise non-standard nucleotides, including non-naturally occurring nucleotides or deoxyribonucleotides. The double-stranded oligonucleotide may contain a modified backbone, for example, phosphorothioate, phosphorodithioate, or other modified backbones known in the art, or may contain non-natural internucleoside linkages. Additional modifications of the RNAi molecules (e.g., 2′-O-methyl ribonucleotides, 2′-deoxy-2′-fluoro ribonucleotides, “universal base” nucleotides, 5-C-methyl nucleotides, one or more phosphorothioate internucleotide linkages, and inverted deoxyabasic residue incoporation) can be found in US Pat. Publication No. 20040019001 (see Summary of the Invention section). Collectively, all such altered RNAi molecules are referred to as modified RNAI molecules.
The sequence of an RNA target of interest, such as a viral or human MRNA transcript, is screened for target sites, for example by using a computer folding algorithm. For example, the sequence of a TAT-001 gene or RNA gene transcript derived from a database (e.g., Genbank) or determined experimentally, using techniques known in the art, is used to generate siRNA having complementarity to the target sequence(s). Target sites that are known, for example, target sites determined to be effective based on studies with other nucleic acid molecules, for example ribozymes or antisense, or targets known to be associated with a disease or condition such as sites containing mutations or deletions, can be used to design siRNA molecules. Various parameters (e.g., secondary or tertiary RNA structure, the nucleobase composition of the target sequence, the degree of homology between various regions of the target sequence, or the relative position of the target sequence within the RNA transcript) can be used to determine which sites are most suitable within the target RNA sequence. Based on these determinations, any number of target sites within the RNA transcript can be chosen to screen siRNA molecules for efficacy, for example by using in vitro RNA cleavage assays, cell culture, or animal models. In a non-lirniting example, anywhere from 1 to 1000 target sites are chosen within the transcript based on the size of the siRNA construct to be used. High throughput screening assays can be developed for screening siRNA molecules using methods known in the art, such as with multi-well or multi-plate assays to determine efficient reduction in target gene expression.
The following non-limiting steps can be used to carry out the selection of siRNAs targeting a given gene sequence or transcript. The target sequence is parsed in silico into a list of all fragments or subsequences of a particular length, for example 23 nucleotide fragments, contained within the target sequence. This step is typically carried out using a custom Perl script, but commercial sequence analysis programs such as Oligo, MacVector, or the GCG Wisconsin Package can be employed as well. In some instances the siRNAs correspond to more than one target sequence; for example in targeting different transcripts of the same gene, targeting different transcripts of more than one gene, or for targeting both the human gene and an animal homolog. In this case, a sub-sequence list of a particular length is generated for each of the targets, and then the lists are compared to find matching sequences in each list. The sub-sequences are then ranked according to the number of target sequences that contain the given sub-sequence to find sub-sequences that are present in most or all of the target sequences. Alternately, the ranking can identify sub-sequences that are unique to a target sequence, such as a mutant target sequence. Such an approach would enable the use of siRNA to target specifically the mutant sequence and not effect the expression of the normal sequence.
In some instances the siRNA sub-sequences are absent in one or more sequences while present in the desired target sequence, as would be the case if the siRNA targets a gene with a paralogous family member that is to remain untargeted. In this example, a sub-sequence list of a particular length is generated for each of the potential targets, and then the lists are compared to find sequences that are present in the target gene but absent in the untargeted paralogue. The ranked siRNA sub-sequences can be further analyzed and ranked according to GC content. A preference can be given to sites containing 30-70% GC, with a further preference to sites containing 40-60% GC. The ranked siRNA sub-sequences can be further analyzed and ranked according to self-folding and internal hairpins. Weaker internal folds are preferred; strong hairpin structures are to be avoided. The ranked siRNA subsequences can be further analyzed and ranked according to whether they have runs of GGG or CCC in the sequence which may make oligonucleotide synthesis problematic and may potentially interfere with RNAI activity. (CCC is searched in the target strand because that will place GGG in the antisense strand.) The ranked siRNA subsequences can be further analyzed and ranked according to whether they have the dinucleotide UU (uridine dinucleotide) on the 3′-end of the sequence, and/or AA on the 5′-end of the sequence (to yield 3′ LJ on the antisense sequence), allowing design of siRNA molecules with terminal TT thymidine dinucleotides.
Typically, four or five target sites are chosen from the ranked list of sub-sequences as described above. For example, in sub-sequences having 23 nucleotides, the 3′ 21 nucleotides of each sub-sequence are then designed and synthesized for the sense strand of the siRNA duplex, while the reverse complement of the 5′ 21 nucleotides of each chosen 23-mer sub-sequence are then designed and synthesized for the antisense strand of the siRNA duplex. If terminal TT residues are desired for the sequence, then the two 3′ terminal nucleotides of both the sense and antisense strands are replaced by TT prior to synthesizing the oligos.
The siRNA, and RNAi molecules in general, may be screened in vitro or in vivo, for example in a cell culture or animal model system, to identify the most active RNAi molecule or the most preferred target site within the target RNA sequence. RNAi nucleic acids of the invention include TAT-001 nucleic acids capable of capable of forming a double-stranded RNA substantially identical (or complementary depending on the respective strand) to a portion of a TAT-001 RNA, preferably a TAT-001 MRNA encoding a TAT-001 polypeptide. RNAi activity may be assayed using the assays described above for measurement of anti-sense activity. The RNAi nucleic acid can correspond to a coding and/or non-coding region of an MRNA encoding such a polypeptide. Preferably, expression of a TAT-001 nucleic acid or polypeptide or both is inhibited by use of RNAi nucleic acids. RNAi oligonucleotides can also contain a variety of modifications.
In an alternate approach, a pool of RNAi constructs specific to a TAT-001 nucleic acid target sequence is used to screen for target sites in cells expressing TAT-001 RNA, such as colon cancer cells. Cells expressing TAT-001 RNA are transfected with the pool of RNAI constructs and cells that demonstrate a phenotype associated with TAT-001 inhibition are sorted. The pool of RNAI constructs can be expressed from transcription cassettes inserted into appropriate vectors. The RNAi from cells demonstrating a positive phenotypic change (e.g., decreased proliferation, decreased TAT-001 mRNA levels or decreased TAT-001 protein expression), are sequenced to determine the most suitable target site(s) within the target TAT-001 RNA sequence.
Another approach is to use double or triple helical structures homologus to the targeted gene, in this case TAT-001. Delivery of the double or triple stranded nucleic acid structure results in the inhibition of the expression of the endogenous gene, similar to antisense oligonucleotides. A review of these RNA interference methods is disclosed in U.S. Pat. No. 6,506,559, incorporated by reference in its entirety herein.
ii.) Ribozymes
In addition to antisense polynucleotides, ribozymes can be used to target and inhibit transcription of cancer-associated nucleotide sequences such as TAT-001 nucleotides. Different kinds of ribozymes have been described, including group I ribozymes, hammerhead ribozymes, hairpin ribozymes, RNase P, and axhead ribozymes (see, e.g., Castanotto et al. (1994) Adv Pharmacol. 25: 289-317).
The general features of hairpin ribozymes are described, e.g., in Hampel et al. (1990) Nucleic Acids Res. 18: 299-304; European Patent Publication No. 0 360 257; and U.S. Pat. No. 5,254,678. Methods of preparation are described in, e.g., WO 94/26877; Ojwang et al. (1993) Proc Natl Acad Sci. U.S.A. 90: 6340-6344; Yamada et al. (1994) Human Gene Ther. 1: 39-45; Leavitt et al. (1995) Proc Natl Acad Sci U.S.A. 92: 699-703; Leavitt et al. (1994) Human Gene Ther. 5: 1151-1120; and Yamada et al. (1994) Virology 205: 121-126.
TAT-001 nucleic acids such as ribozymes, RNAi constructs, and anti-sense molecules—collectively TAT-001 therapeutic nucleic acids—may be introduced into a cell containing the target nucleotide sequence using any techniques known in the art. In one example, the therapeutic nucleic acid is introduced by formation of a conjugate with a ligand binding molecule (e.g., cell surface receptors, growth factors, and other cytokines) as described in PCT Publication No. WO 91/04753. Preferably, conjugation of the ligand binding molecule does not substantially interfere with the ability of the ligand binding molecule to bind to its corresponding molecule or receptor, or block entry of the sense or antisense oligonucleotide or its conjugated version into the cell. In another embodiment, a TAT-001 therapeutic nucleic acid may be introduced into a cell containing the target nucleic acid sequence, e.g., by formation of a polynucleotide-lipid complex, as described in WO 90/10448. It is understood that the use of antisense molecules or knock-out and knock-in models may also be used in screening assays as discussed above, in addition to methods of treatment. Delivery may also be per gene therapy methods described below.
Thus, the present invention provides for the therapeutic or prophylactic use of TAT-001 nucleic acids that are complementary to at least eight consecutive nucleotides of a gene or cDNA encoding a TAT-001 polypeptide. The nucleic acids can be antisense molecules, dsRNA or siRNA molecules, or vectors to produce such in the case of RNAI. TAT-001 nucleic acids may also be used directly as immunogens, or in vectors to provide immunogens through protein expression, for vaccination, or to design guide sequences for therapeutic and prophylactic ribozymes.
iii.) Gene Therapy
In a specific embodiment, TAT-001 nucleic acid molecules are used for gene therapy (see for example Hoshida et al. (2002) Pancreas. 25: 111-121; Ikuno (2002) Invest Ophthalmol Vis Sci. 43: 2406-2411; Bollard (2002) Blood. 99: 3179-3187; Lee (2001) Mol Med. 7: 773-782), such as in the treatment or prevention of cancer. Gene therapy refers to administration to a subject of an expressed or expressible nucleic acid. Any of the methods for gene therapy available in the art can be used according to the present invention. In one example, the TAT-001 nucleic acid can be administered as a pharmaceutical composition, for example as part of an expression vector that expresses a TAT-001 polypeptide or chimeric protein thereof in a suitable host. In particular, such a nucleic acid has a promoter (e.g., inducible or constitutive, and, optionally, tissue-specific) operably linked to the polypeptide coding region. In another example, a TAT-001 nucleic acid molecule is used in which the coding sequences and any other desired sequences are flanked by regions that promote homologous recombination at a desired site in the genome, thus providing for intrachromosomal expression of the nucleic acid (Koller and Smithies (1989) Proc Natl Acad Sci. U.S.A. 86: 8932-8935; Zijistra et al. (1989) Nature 342: 435-438).
Delivery of the TAT-001 nucleic acid into a patient may be direct (i.e. in vivo gene therapy), the patient is directly exposed to the nucleic acid or nucleic acid-carrying vector. Alternatively, delivery of the nucleic acid into the patient may be indirect (i.e. ex vivo gene therapy), cells are first transformed with the nucleic acid in vitro and then transplanted into the patient.
TAT-001 nucleic acids, TAT-001 polypeptides (for example, to target the therapy to cells which bind the polypeptide), or both may be utilized in gene delivery vehicles. The gene delivery vehicle may be of viral or non-viral origin (see Jolly (1994) Cancer Gene Ther. 1: 51-64; Kimura (1994) Human Gene Ther. 5: 845-852; Connelly (1995) Human Gene Ther. 1: 185-193; and Kaplitt (1994) Nat Gen. 6: 148-153). Gene therapy vehicles for delivery of constructs can be administered either locally or systemically. These constructs can utilize viral or non-viral vector approaches. Expression of such coding sequences can be induced using endogenous mammalian or heterologous promoters. Expression of the coding sequence can be either constitutive or regulated.
The present invention can employ recombinant retroviruses constructed to carry or express a selected nucleic acid molecule. Retrovirus vectors that can be employed include those described in EP 0 415 731; WO 90/07936; WO 94/03622; WO 93/25698; WO 93/25234; U.S. Pat. No. 5,219,740; WO 93/11230; WO 93/10218; Vile and Hart, (1993) Cancer Res. 53: 3860-3864; Vile and Hart (1993) Cancer Res. 53: 962-967; Ram et al. (1993) Cancer Res. 53: 83-88; Takamiya et al. (1992) J Neurosci Res. 33: 493-503; Baba et al. (1993) J Neurosurg. 79: 729-735; U.S. Pat. No. 4,777,127; GB Patent No. 2,200,651; and EP 0 345 242. Preferred recombinant retroviruses include those described in WO 91/02805.
Packaging cell lines suitable for use with the above-described retroviral vector constructs may be readily prepared (see PCT Publication Nos. WO 95/30763 and WO 92/05266), and used to create producer cell lines (also termed vector cell lines) for the production of recombinant vector particles. Preferably, packaging cell lines are made from human (such as HT-1080, 293, or 293T cells), mouse (NIH 3T3 cells), or mink parent cell lines, thereby allowing production of recombinant retroviruses that can survive inactivation in human serum.
The present invention also employs alphavirus-based vectors that can function as gene delivery vehicles. Such vectors can be constructed from a wide variety of alphaviruses, including, for example, Sindbis virus vectors, Semliki forest virus (ATCC VR-67; ATCC VR-1247), Ross River virus (ATCC VR-373; ATCC VR-1246) and Venezuelan equine encephalitis virus (ATCC VR-923; ATCC VR-1250; ATCC VR 1249; ATCC VR-532). Representative examples of such vector systems include those described in U.S. Pat. Nos. 5,091,309; 5,217,879; and 5,185,440; and PCT Publication Nos. WO 92/10578; WO 94/21792; WO 95/27069; WO 95/27044; and WO 95/07994.
Gene delivery vehicles of the present invention can also employ parvovirus such as adeno-associated virus (AAV) vectors. Representative examples include the AAV vectors disclosed by Srivastava in WO 93/09239, Samulski et al. (1989) J. Vir. 63: 3822-3828; Mendelson et al. (1988) Virology 166: 154-165; and Flotte et al. (1993) Proc Natl Acad Sci. U.S.A. 90:10613-10617.
Representative examples of adenoviral vectors include those described by Berkner (1988) Biotechniques 6: 616-627; Rosenfeld et al. (1991) Science 252: 431-434; WO 93/19191; Kolls et al. (1994) Proc Natl Acad Sci. U.S.A. 91: 215-219; Kass-Bisler et al. (1993) Proc Natl Acad Sci. U.S.A. 90: 11498-11502; Guzman et al. (1993) Circulation 88: 2838-2848; Guzman et al. (1993) Cir Res. 73: 1202-1207; Zabner et al. (1993) Cell 75: 207-216; Li et al. (1993) Hum Gene Ther. 4: 403-409; Cailaud et al. (1993) Eur J Neurosci. 5: 1287-1291; Vincent et al. (1993) Nat Genet. 5: 130-134; Jaffe et al. (1992) Nat Genet. 1: 372-378; and Levrero et aL (1992) Gene. 101: 195-202. Exemplary adenoviral gene therapy vectors employable in this invention also include those described in WO 94/12649, WO 93/03769; WO 93/19191; WO 94/28938; WO 95/11984 and WO 95/00655. Administration of DNA linked to kill adenovirus as described in Curiel (1992) Hum Gene Ther. 3: 147-154 may be employed.
Other gene delivery vehicles and methods may be employed; including polycationic condensed DNA linked or unlinked to killed adenovirus alone, for example Curiel (1992) Hum Gene Ther. 3: 147-154; ligand-linked DNA, for example see Wu (1989) J Biol Chem. 264: 16985-16987; eukaryotic cell delivery vehicle cells, for example see U.S. Pat Nos. 6,013,517; 6,333,195; 6,015,686; 6,342,372 and 6,376,236; deposition of photopolymerized hydrogel materials; hand-held gene transfer particle gun, as described in U.S. Pat. No. 5,149,655; ionizing radiation as described in U.S. Pat. No. 5,206,152 and in WO 92/11033; and/or nucleic charge neutralization or fusion with cell membranes. Additional approaches are described in Philip (1994) Mol Cell Biol. 14: 2411-2418, and in Woffendin (1994) Proc Natl Acad Sci. U.S.A. 91: 1581-1585.
Naked DNA may also be employed, for example as described in WO 90/11092 and U.S. Pat. No. 5,580,859. Uptake efficiency may be improved using biodegradable latex beads. DNA coated latex beads are efficiently transported into cells after endocytosis initiation by the beads. The beads may be treated to increase hydrophobicity and thereby facilitate disruption of the endosome and release of the DNA into the cytoplasm. In another embodiment, liposomes are used as gene delivery vehicles, for example as described in U.S. Pat. No. 5,422,120, PCT Publication Nos. WO 95/13796, WO 94/23697, and WO 91/14445, and EP No. 0 524 968.
Further non-viral delivery suitable for use includes mechanical delivery systems such as the approach described in Woffendin et al. (1994) Proc Natl Acad Sci. U.S.A. 91: 11581 -11585. Moreover, the coding sequence and the product of expression of such can be delivered through deposition of photopolymerized hydrogel materials. Other conventional methods for gene delivery that can be used for delivery of the coding sequence include, for example, use of hand-held gene transfer particle gun, as described in U.S. Pat. No. 5,149,655; and use of ionizing radiation for activating transferred gene, as described in U.S. Pat. No. 5,206,152 and PCT Publication No. WO 92/11033.
Polypeptides
The invention also provides TAT-001 polypeptides. Polypeptides of the invention have a variety of uses, including, but not limited to: immunogenic compositions, screening for modulators of TAT-001 expression, screening for molecules that bind to TAT-001, and use as reagents and controls in assays of TAT-001 protein, such as diagnostic or prognostic assays.
The TAT-001 protein preferably has the amino acid sequence of a naturally occurring TAT-001 found in a human, fungus, animal, plant, or microorganism, or a sequence derived therefrom. Preferably the TAT-001 is a human TAT-001. By human TAT-001 is meant a protein that can be found in at least one human. It will be apparent to one skilled in the art that peptides for use in the invention include TAT-001 and TAT-001 fragments, derivatives, and modified forms (e.g., analogues) thereof.
TAT-001 polypeptide sequences can be initially identified by substantial amino acid sequence similarity and/or identity to the TAT-001 polypeptide sequences described herein (e.g., SEQ ID NO: 1, 3, 5, or 8). Such similarity or identity can be based on the overall amino acid sequence, and is generally determined as described above (e.g., by an assessment of homology, using, for example, sequence alignment software, such as a BLAST program (Basic Local Alignment Search Tool; (Altschul et al. (1990) J Mol Biol 215: 403-410), NCBI BLAST2.0 software as defmed by Altschul et al. (1997) Nucleic Acids Res. 25: 3389-3402, using Smith Waterman Alignment (Smith and Waterman (1981) J Mol Biol 147: 195-197) as incorporated into GeneMatcher Plus™, or, preferably bl2seq (Tatusova and Madden (1999) FEMS Microbiol Lett. 174: 247-250)). TAT-001 polypeptide sequences may alternatively be initally identified through structural homology or analogy, as determined by the functional or binding assays described herein and their results as compared to those of the TAT-001 polypeptide sequences described herein (e.g., SEQ ID NO: 1, 3, 5, or 8) in the same assay. For example, an antibody to TAT-001 may be used to isolate polypeptides with at least a partial structure homologous to the TAT-001 epitope recognized by the antibody, and such polypeptides could then be further assessed for homology or analogy, such as might have been missed by, for example, an automated BLAST alignment. Exemplary assays are those that suggest or indicate cancer or cellular proliferative diseases at a molecular or phenotypic level or are useful for carrying out the methods of the invention. Such assays are known in the art or described herein (e.g., see Screening Assays, below). Activity as measured in such assays of a TAT-001 polypeptide is preferred to be at least 0.1%, at least 1%, at least 5%, or at least 10% that of a TAT-001 polypeptide sequence described herein (e.g., SEQ ID NO: 1, 3, 5, or 8). More preferably, the polypeptide has at least 25%, at least 50%, at least 75%,or at least 90% of the activity of a TAT-001 polypeptide sequence described herein (e.g., SEQ ID NO: 1, 3, 5, or 8). Most preferably, the polypeptide has at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% of the activity of a TAT-001 polypeptide sequence described herein (e.g., SEQ ID NO: 1, 3, 5, or 8). Preferred TAT-001 polypeptides of the invention retain one or more activities of TAT-001, however, substantially homologous TAT-001 polypeptides need not be active to be useful, and as such may be useful, for example, as controls for functional TAT-001 polypeptides. Specific functional residues or combinations thereof may also be delineated in part through comparative assays, such as comparing the activity of the native sequence in a binding assay to that of a mutagenized sequence that lacks functional activity, as might be produced by techniques including but not limited to alanine scanning (see for example Chatellier et al. (1995) Analytical Biochemistry 229: 282 -290), site-directed mutagenesis (Near et al. (1993) Mol Immunol. 30: 369-377), or saturation mutagenesis (Jeffrey et al. (1995) Nat Struct Biol. 2: 466-471).
Additional TAT-001 polypeptides, including homologues, paralogues, and orthologues from species other than human, may be obtained using standard cloning techniques, screening techniques, or homology search techniques. For example, a phage display library derived from MRNA from murine cells may be screened with anti-TAT-001 antibodies to identify TAT-001 homologues. Alternatively, a library may be screened using a yeast two-hybrid system and a TAT-001 binding protein as bait. Additional TAT-001 polypeptides may also be obtained from natural sources such as cell lysates via purification or can be synthesized using well known and commercially available techniques. TAT-001 polypeptides identified as xenologues include sequences from Pan troglodytes (GenBank GI: 55634139; SEQ ID NO: 28), Mus musculus (GenBank GIs: 48597001, 12856631, 12849896, 13097453; SEQ ID NO: 12, 15, 18, and 21, respectively), Rattus norveticus (GenBank GI: 34862850; SEQ ID NO: 25), and Gallus Gallus (GenBank GI: 50749572; SEQ ID NO: 32). An approximate alignment of these sequences is provided in
Fragments of a TAT-001 polypeptide may be used in the methods of the invention; preferably the fragments include an intact epitope that occurs in the biologically active wildtype TAT-001. The fragments comprise at least 4 consecutive amino acids of a TAT-001 polypeptide. Preferably, the fragment comprises at least 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, or at least 190 consecutive amino acids of a TAT-001 polypeptide. In one embodiment, the fragment is from a human TAT-001 polypeptide. Preferably, the fragment contains an amino acid sequence conserved among mammalian TAT-001s, more preferably among primate TAT-001s. The skilled person can determine whether or not a particular fragment has activity using the techniques known in the art or disclosed herein for assessing the appropriate activity. Any given fragment of a polypeptide may or may not possess a finctional activity of the parent polypeptide. Preferably the fragment has substantial sequence identity over the length of the corresponding TAT-001 sequence.
Fragments may be part of fusion proteins comprising or consisting of one or more TAT-001 fragments. Such fusion proteins may alter the order of the normal TAT-001 amino acid sequence or repeat certain elements or structures therein. Multiple fragments may be linked by non-TAT-001 fragments. Such non-TAT-001 fragments may or may not be considered immunogenic, and may or may not induce the included fragments to maintain a particular structural conformation or conformations. Fusion proteins comprising or consisting of one or more TAT-001 fragments are contemplated as encompassed in the definition of TAT-001 fragments (fragments of a TAT-001 polypeptide).
Alterations in the amino acid sequence of a protein can occur which do not affect the function of a protein. These include amino acid deletions, insertions, and substitutions, and can result from alternative splicing and/or the presence of multiple translational start sites or stop sites. Polymorphisms may arise from infidelity of the translational process. Thus, changes in amino acid sequence which do not affect biological or immunological finction may be tolerated while maintaining substantially the same activity.
A “derivative” of a polypeptide includes a polypeptide comprising an amino acid sequence of a parent polypeptide that has been altered by the introduction of amino acid residue substitutions, deletions, or additions, and/or amino acid modifications, e.g., phosphorylation and glycosylation. Such introductions may be engineered for a polypeptide or an encoding nucleic acid or produced naturally. A derivative may also encompass homologues, analogues and orthologues of a parent polypeptide. The derivative polypeptide may possess a similar or identical function to the parent polypeptide. TAT-001 derivatives also preferably possess at least a degree of the antigenicity and/or immunogenicity of the protein or polypeptide from which they are derived.
An example of a derivative or variant of a TAT-001 polypeptide for use in the present invention is a TAT-001 polypeptide as defined by SEQ ID NO: 5, apart from the substitution of one or more amino acids with one or more other amino acids. Amino acid substitutions may be conservative or semi-conservative as known in the art and preferably do not significantly affect the desired activity of the polypeptide. Substitutions may be naturally occurring or may be introduced, for example, using mutagenesis (e.g., Hutchinson et al. (1978) J Biol Chem. 253: 6551-6560). In one example, the single amino acid (histidine vs. tyrosine) difference between SEQ ID NO: 5 and SEQ ID NO: 8 demonstrates an amino acid substitution as described above that could allow SEQ ID NO: 8 to be termed a variant of a TAT-001 polypeptide. Typically “variant” is used to describe a naturally occuring difference in sequence, while “derivative” typically describes a difference produced recombinantly or through other synthetic means, but may be used interchangeably or indiscriminately. Thus, the amino acids glycine, alanine, valine, leucine and isoleucine can often be substituted for one another (amino acids having aliphatic side chains). Of these possible substitutions, it is preferred that glycine and alanine are used to substitute for one another (since they have relatively short side chains) and that valine, leucine and isoleucine are used to substitute for one another (since they have larger hydrophobic aliphatic side chains).
Other amino acids which can often be substituted for one another include: phenylalanine, tyrosine, and tryptophan (amino acids having aromatic side chains); lysine, arginine, and histidine (amino acids having basic side chains); aspartate and glutamate (amino acids having acidic side chains); asparagine and glutamine (amino acids having amide side chains); cysteine and methionine (amino acids having sulphur-containing side chains); and aspartic acid and glutamic acid can substitute for phospho-serine and phospho-threonine, respectively (amino acids with acidic side chains).
In a particular embodiment, the substituted amino acid(s) significantly affect the activity of the TAT-001 polypeptide and may be selected specifically to render dominant negative activity upon the peptide. In another embodiment, the substituted amino acid(s) may be selected to render the polypeptide constitutively active. Such alterations may be useful in screens or assays, such as phenotypic screens or enzymatic assays, or in the use of a TAT-001 polypeptide or fusion or conjugate thereof as a therapeutic molecule. Alterations that impact immunogenicity typically will be used to increase immunogenicity of particular sequences, such as increasing accessibility of the desired epitope, or altering loop stability (see, for example, Dai et al. (2002) J Biol Chem. 277: 161-168; Srivastava et al. (2003)J Virol. 77: 2310 -2320; Yang et al. (2004) J Virol. 78: 4029-4036; Oomen et al. (2003) J Mol Biol. 328: 1083-1089), but may also be used to reduce immunogenicity of particular epitopes, such as when a heterogenous sequence is used to produce antibodies for use in humans, e.g., when murine peptides are used for immunization which contain an undesirable epitope not present in the human sequence, such as one that might produce undesirable cross-reactivity with other human proteins (see, for a related example, Vanderschueren et al. (1994) Thromb Haemost. 72: 297-301; Collen et al. (2000) Circulation. 102: 1766-1772; Su et al. (2004) Acta Biochim Biophys Sin (Shanghai) 36: 336-342). Techniques are known to the skilled artisan for making and measuring the impact of such alterations.
Amino acid deletions or insertions may also be made relative to a TAT-001 polypeptide sequence. Thus, for example, amino acids which do not have a substantial effect on the biological and/or immunological activity of the polypeptide, or at least which do not eliminate such activity, may be deleted. Such deletions can be advantageous since the overall length and the molecular weight of a polypeptide can be reduced while still retaining activity. Similarly, deletions may be made to produce an inactive form of a TAT-001 polypeptide.
Polypeptides comprising amino acid insertions relative to a TAT-001 polypeptide sequence are also within the scope of the invention. Such changes may alter the properties of a polypeptide used in the present invention (e.g., to assist in identification, purification or expression, as explained above in relation to fusion proteins). For example, insertion of an IL-1 beta peptide sequence may be used to enhance immunogenicity (see Beckers et al. (1993) J Immunol. 151: 1757-1764). Such amino acid changes can be made using any suitable technique, for example, site-directed mutagenesis (Hutchinson et al. (1978) supra).
It should be appreciated that amino acid substitutions or insertions to the polypeptide for use in the present invention can be made using naturally occurring or non-naturally occurring amino acids. Whether or not natural or synthetic amino acids are used, it is preferred that only L-amino acids are present.
Epitopes
It is well known that is possible to screen an antigenic protein or polypeptide to identify epitopic regions, i.e., those regions responsible for antigenicity or immunogenicity. Amino acid and peptide characteristics well known to the skilled person can be used to predict the antigenic index (a measure of the probability that a region is antigenic) of a TAT-001 polypeptide. For example, the PeptideStructure program (Jameson and Wolf (1988) Comput Appl Biosci. 4: 181-186) and/or a technique referred to as threading (Altuvia et al. (1995) J Mol Biol. 249: 244-250) may be used. Thus, the TAT-001 polypeptides may include one or more such epitopes or be sufficiently similar to such regions as to retain antigenic or immunogenic properties. Methods well known to the skilled person can be used to test fragments, and/or homologues and/or derivatives of a polypeptide for immunogenicity. Thus, the fragments for use in the present invention may include one or more such epitopic regions or be sufficiently similar to such regions to retain their antigenic or immunogenic properties. Isolated TAT-001 polypeptides of the invention (and their encoding nucleic acids) may therefore be screened for use in inducing an immune response based on known and/or predicted immunogenicity, or judged individually. Such immunogenic polypeptides may be refered to as “immunogenic isolated polypeptides” of the invention.
Polypeptide Expression
In another aspect, the invention provides for isolated or recombinant TAT-001 polypeptides or fragments. The isolated or recombinant TAT-001 polypeptides or fragments may also be fused to other moieties. Such moieties or amino acid sequences may be optionally removed as required by incorporating a cleavable sequence or moiety as an additional sequence or part thereof. In particular, fusions of the polypeptides or fragments thereof with localization-reporter proteins such as the Green Fluorescent Protein (U.S. Pat. Nos. 5,625,048; 5,777,079; 6,054,321 and 5,804,387) or the DsRed fluorescent protein (Matz et al. (1999) Nat Biotech. 17: 969-973) are specifically contemplated. Also contemplated are affinity tag and epitope tag fuisions, for example, HIS-tag, HA-tag, FLAG-tag, and Myc-tag fusions, respectively. Fusions can be useful in improving recombinant expression, improving purification, or regulation of expression in particular expression systems. For example, an additional sequence may provide some protection against proteolytic cleavage. Additional N-terminal or C-terminal amino acid sequences may, however, be present simply as a result of a particular technique used to obtain a polypeptide and need not provide any particular advantageous characteristic to the polypeptide. Such polypeptides are within the scope of the present invention.
The polypeptides or fragments thereof may be provided in substantially pure form, that is to say free, to a substantial extent, from other proteins. Thus, a polypeptide may be provided in a composition in which it is the predominant component present (i.e., it is present at a level of at least 50%; preferably at least 75%, at least 90%, or at least 95%; when determined on a weight/weight basis excluding solvents, carriers, or coupling agents).
The skilled person will appreciate that for the preparation of one or more such polypeptides, the preferred approach will be based on recombinant DNA techniques (some of which may be represented in “Nucleic Acids” above). Recombinant TAT-001 polypeptides may be prepared by processes well known in the art from genetically engineered host cells comprising expression systems. Accordingly, the present invention also relates to expression systems which comprise a TAT-001 polypeptide and/or TAT-001 nucleic acid, to host cells which are genetically engineered to incorporate such expression systems or portions thereof, and to the production of TAT-001 polypeptides by recombinant techniques. Cell-free translation systems can also be employed to produce recombinant polypeptides (e.g., rabbit reticulocyte lysate, wheat germ lysate, SP6/T7 in vitro T&T and RTS 100 E. coli Hy transcription and translation kits from Roche Diagnostics Ltd., Lewes, UK; and the TNT Quick coupled Transcription/Translation System from Promega UK, Southampton, UK).
A wide variety of expression systems (a term inclusive of expression constructs) can be used, such as and without limitation, chromosomal, episomal and virus-derived systems, e.g., vectors derived from bacterial plasmids, from bacteriophage, from transposons, from yeast episomes, from insertion elements, from yeast chromosomal elements, from viruses such as baculoviruses, papova viruses such as SV40, vaccinia viruses, adenoviruses, fowl pox viruses, pseudorabies viruses and retroviruses, and vectors derived from combinations thereof, such as those derived from plasmid and bacteriophage genetic elements, such as cosmids and phagemids. Generally, any system or vector which is able to maintain, propagate or express a nucleic acid to produce a polypeptide in a host may be used. The appropriate TAT-001 nucleic acid sequence may be inserted into an expression system by any variety of well-known and routine techniques, such as those set forth in Sambrook et al., supra.
An expression system or construct can be introduced into a host cell. The host cell comprising the expression construct can be any suitable prokaryotic or eukaryotic cell. Expression systems in bacteria include those described in Chang et al. (1978) Nature 275: 617-624; Goeddel et al. (1979) Nature 281: 544-548; Goeddel et al. (1980) Nucleic Acids Res. 8: 4057-4074; EP 36,776; U.S. Pat. No. 4,551,433; deBoer et al. (1983) Proc Natl Acad Sci. U.S.A. 80: 21-25; and Siebenlist et al. (1980) Cell 20: 269-281.
Representative examples of host cells include bacterial cells (e. g., E. coli, Streptococci, Staphylococci, Streptomyces and Bacillus subtilis cells); fungal cells (e.g., yeast cells and Aspergillus cells); insect cells (e.g., Drosophila S2 and Spodoptera Sf9 cells); animal cells (e.g., CHO, COS, HeLa, C127, 3T3, HEK 293, BHK, and Bowes melanoma cells); and plant cells.
Expression systems in yeast include those described in Hinnen et al. (1978) Proc Natl Acad Sci. U.S.A. 75: 1929-1933; Ito et al. (1983) J Bacteriol. 153: 163-168; Kurtz et aL (1986) Mol Cell Biol. 6: 142-149; Kunze et al. (1985) J Basic Microbiol. 25: 141-144; Gleeson et al. (1986) J Gen Microbiol. 132: 3459-3465; Roggenkamp et al. (1986) Mol Gen Genet. 202: 302-308; Das et al. (1984) J Bacteriol. 158: 1165-1167; De Louvencourt et al. (1983) J Bacteriol. 154: 737-742; Van den Berg et al. (1990) Biotechnology. 8: 135-139; Kunze et al. (1985) J Basic Microbiol. 25: 141-144; Cregg et al. (1985) Mol Cell Biol. 5: 3376-3385; U.S. Pat. Nos. 4,837,148; 4,929,555; Beach et al. (1982) Nature 300: 706-709; Davidow et al. (1985) Curr Genet. 10: 39-48; Gaillardin et al. (1985) Curr Genet. 10: 49-58; Ballance et al. (1983) Biochem Biophys Res Commun. 112: 284-289; Tilburn et al. (1983) Gene. 26: 205-22; Yelton et al. (1984) Proc Natl Acad Sci. U.S.A. 81: 1470-1474; Kelly and Hynes (1985) EMBO J. 4: 475-479; US Pat. No. 4,937,189; EP 244,234; and WO 91/00357.
Expression of heterologous genes in insects may be accomplished as described in U.S. Pat. No. 4,745,051; Friesen et al. (1986) “The Regulation of Baculovirus Gene Expression” in: The Molecular Biology of Baculoviruses (W. Doerfier, ed.); EP 127,839; EP 155,476; Vlak et al. (1988) J Gen Virol. 69: 765-776; Miller et al. (1988) Ann Rev Microbiol. 42: 177-199; Carbonell et al. (1988) Gene. 73: 409-418; Maeda et al. (1985) Nature 315: 592-594; Lebacq-Verheyden et al. (1988) Mol Cell Biol. 8: 3129-3135; Smith et aL. (1985) Proc Natl Acad Sci. U.S.A. 82: 8404-8408; Miyajima et al. (1987) Gene. 58: 273-281; and Martin et al. (1988) DNA. 7: 99-106. Numerous baculoviral strains and variants and corresponding permissive insect host cells from hosts are described in Luckow and Summers (1988) Biotechnology. 6: 47-55; Luckow (1993) Curr Opin Biotechnol. 4: 564-572; Miller et al. in Genetic Engineering (Setlow, J. K. et al. eds.), Vol. 8, pp. 277-279 (Plenum Publishing, 1986); and Maeda et al. (1985) Nature 315: 592-594.
Mammalian expression can be accomplished as described in Dijkema et al. (1985) EMBOJ. 4: 761-767; Gorman et al. (1982b) Proc Natl Acad Sci. U.S.A. 79: 6777-6781; Boshart et al. (1985) Cell 41: 521-530; and U.S. Pat. No. 4,399,216. Other features of mammalian expression can be facilitated as described in Ham and McKeehan (1979) Meth Enz. 58: 44-93; Barnes and Sato (1980) Anal Biochem. 102: 255-270; U.S. Pat. Nos. 4,767,704; 4,657,866; 4,927,762; 4,560,655; WO 90/103430; WO 87/00195; and U.S. Pat. No. RE 30,985.
Expression systems or constructs, in whole or in part, can be introduced into host cells using any technique known in the art. These techniques include transferrin-polycation-mediated DNA transfer, transfection with naked or encapsulated nucleic acids, liposome-mediated cellular fusion, intracellular transportation of DNA-coated latex beads, protoplast fusion, viral infection, electroporation, “gene gun,” calcium phosphate-mediated transfection, DEAE-dextran mediated transfection, transvection, microinjection, cationic lipid-mediated transfection, electroporation, transduction, scrape loading, or ballistic introduction (see e.g., Davis et al. (1986) Basic Methods in Molecular Biology and Sambrook et al. (1989) Molecular Cloning: A Laboratory Manual, 2nd Ed., Cold Spring Harbour laboratory Press, Cold Spring Harbour, N.Y.).
The expression systems may contain control regions that regulate as well as engender expression. For example, expression of an endogenous gene encoding a protein of the invention can also be manipulated by introducing, by homologous recombination, a DNA construct comprising a transcription unit in frame with the endogenous gene, to form a homologously recombinant cell comprising the transcription unit. The transcription unit comprises a targeting sequence, a regulatory sequence, an exon, and an unpaired splice donor site. The new transcription unit can be used to turn the endogenous gene on or off as desired. This method of affecting endogenous gene expression is taught, for example, in U.S. Pat. No. 5,641,670.
Appropriate secretion signals may be incorporated into the TAT-001 polypeptide to allow secretion of the translated protein into the lumen of the endoplasmic reticulum, the periplasmic space or the extracellular environment. These signals may be endogenous to the TAT-001 polypeptide or they may be heterologous signals.
If a TAT-001 polypeptide is to be expressed for use in cell-based screening assays, it is preferred that the polypeptide be produced at the cell surface. In this event, the cells may be harvested prior to use in the screening assay. If the TAT-001 polypeptide is secreted into the medium, the medium can be recovered in order to isolate the polypeptide. If produced intracellularly, the cells must first be lysed before the TAT-001 polypeptide is recovered.
TAT-001 polypeptides can be recovered and purified from recombinant cell cultures by well-known methods including, ammonium sulphate or ethanol precipitation, acid extraction, anion or cation exchange chromatography, phosphocellulose chromatography, affinity chromatography, hydrophobic interaction chromatography, hydroxylapatite chromatography, molecular sieving chromatography, centrifugation methods, electrophoresis methods and lectin chromatography. In one embodiment, a combination of these methods is used. In another embodiment, high performance liquid chromatography is used. In a further embodiment, an antibody which specifically binds to a TAT-001 polypeptide can be used to deplete a sample comprising a TAT-001 polypeptide of the polypeptide or to purify the polypeptide. Techniques well-known in the art, may be used for refolding to regenerate native or active conformations of the TAT-001 polypeptides when the polypeptides have been denatured during isolation and or purification, should such be desired.
Transgenics and Knockouts
The polypeptides of the invention can also be expressed, or otherwise have their expression altered (for example, a “knockout”), in transgenic animals. Animals may be of any species, including, but not limited to, mice, rats, rabbits, hamsters, guinea pigs, pigs, micro-pigs, goats, sheep, cows and non-human primates (e.g., baboons, monkeys, and chimpanzees) may be used to generate transgenic animals. Preferably, transgenic animals of the invention are mammals. Partial murine TAT-001 genomic sequence is provided (SEQ ID NO: 24) and remaining sequence can be determined using the methods of Example 5 and standard DNA sequencing methods. Partial genomic sequences are also provided for chimpanzee (SEQ ID NO: 31), rat (SEQ ID NO: 27), and chicken (SEQ ID NO: 34). In a specific embodiment, techniques described herein or otherwise known in the art, are used to express polypeptides of the invention in humans, as part of a gene therapy protocol.
Any technique known in the art may be used to introduce the transgene (i.e., polynucleotides of the invention) into animals to produce the founder lines of transgenic animals. Such techniques include, but are not limited to, pronuclear microinjection (Paterson et al. (1994) Appl Microbiol Biotechnol. 40: 691-698; Carver et al. (1993) Biotechnology (NY) 11: 1263-1270; Wright et al. (1991) Biotechnology (NY) 9: 830-834; and US Pat. No. 4,873,191); retrovirus mediated gene transfer into germ lines (Van der Putten et al. (1985) Proc Natl Acad Sci. U.S.A. 82: 6148-6152), blastocysts or embryos; gene targeting in embryonic stem cells (Thompson et al. (1989) Cell 56: 313-321); electroporation of cells. or embryos (Lo (1983) Mol Cell Biol. 3: 1803-1814); introduction of the polynucleotides of the invention using a gene gun (see, e.g., Ulmer et al. (1993) Science 259: 1745-1749; introducing nucleic acid constructs into embryonic pleuripotent stem cells and transferring the stem cells back into the blastocyst; and sperm-mediated gene transfer (Lavitrano et al. (1989) Cell 57: 717-723). For a review of such techniques, see Gordon (1989) Intl Rev Cytol. 115: 171-229, which is incorporated by reference herein in its entirety.
Any technique known in the art may be used to produce transgenic clones containing polynucleotides of the invention, for example, nuclear transfer into enucleated oocytes of nuclei from cultured embryonic, fetal, or adult cells induced to quiescence (Campell et al. (1996) Nature 380: 64-66; Wilmut et al. (1997) Nature 385: 810-813).
The present invention provides for transgenic animals that carry the transgene in all their cells, as well as animals which carry the transgene in some, but not all their cells (i.e., mosaic or chimeric animals). The transgene may be integrated as a single transgene or as multiple copies such as in concatamers (e.g., head-to-head tandems or head-to-tail tandems). Thus, animal models of TAT-001 overproduction can be generated by integrating one or more TAT-001 sequences into the genome of an animal, according to standard transgenic techniques. Moreover, the effect of TAT-001 gene mutations (e.g., dominant gene mutations) can be studied using transgenic mice carrying mutated TAT-001 transgenes or by introducing such mutations into the endogenous TAT-001 gene, using standard homologous recombination techniques. The transgene may also be selectively introduced into and activated in a particular cell type by following, for example, the teaching of Lasko et al. ((1992) Proc Natl Acad Sci. U.S.A. 89: 6232-6236).
The regulatory sequences required for such a cell-type specific activation will depend upon the particular cell type of interest, and will be apparent to those of skill in the art. When it is desired that the polynucleotide transgene be integrated into the chromosomal site of the endogenous gene, gene targeting is preferred. Briefly, vectors containing some nucleotide sequences homologous to the endogenous TAT-001 gene are designed for the purpose of integrating, via homologous recombination with chromosomal sequences, into and disrupting the function of the nucleotide sequence of the endogenous gene. The transgene may also be selectively introduced into a particular cell type, thus inactivating the endogenous gene in only that cell type (see e.g., Gu et al. (1994) Science 265: 103-106). The regulatory sequences required for such a cell-type specific inactivation will depend upon the particular cell type of interest, and will be apparent to those of skill in the art.
Once transgenic animals have been generated, the expression of the recombinant gene may be assayed utilizing standard techniques. Initial screening may be accomplished by Southern blot analysis or PCR techniques to analyze animal tissues to verify that integration of the transgene has taken place. The level of MRNA expression of the transgene in the tissues of the transgenic animals may also be assessed using, for example, Northern blot analysis of tissue samples from the animal, in situ hybridization analysis, and reverse transcriptase-PCR (rt-PCR). Samples of transgenic gene-expressing tissue may also be evaluated immunocytochemically or immunohistochemically using antibodies specific for the transgene product.
Once the founder animals are produced, they may be bred, inbred, outbred, or crossbred to produce colonies of the particular animal. For example breeding strategies may include outbreeding of founder animals with more than one integration site in order to establish separate lines; inbreeding of separate lines in order to produce compound transgenics that express the transgene at higher levels because of the effects of additive expression of each transgene; crossing of heterozygous transgenic animals to produce animals homozygous for a given integration site in order to both augment expression and eliminate the need for screening of animals by DNA analysis; crossing of separate homozygous lines to produce compound heterozygous or homozygous lines; and breeding to place the transgene on a distinct background appropriate for an experimental model of interest.
Endogenous gene expression may also be reduced by inactivating or “knocking out” the TAT-001 gene and/or its promoter using targeted homologous recombination in animals. (e.g., see Smithies et al. (1985) Nature 317: 230-234; Thomas and Capecchi (1987) Cell 51: 503-512; Thompson et al. (1989) Cell 5: 313-321; and Zijistra et al. (1989) Nature 342: 435-438; each of which is incorporated by reference herein in its entirety). Characterization of TAT-001 genes provides information that allows TAT-001 knockout animal models to be developed by homologous recombination. A “knockout animal” is preferably a mammal, and more preferably a mouse, containing a knockout mutation, as defmed below. By a “knockout mutation” is meant an artificially-induced alteration in a nucleic acid molecule (created by recombinant DNA technology or deliberate exposure to a mutagen) that reduces the biological activity of the polypeptide normally encoded therefrom by at least 80% relative to the unmutated gene. The mutation can be, without limitation, an insertion, deletion, frameshift mutation, or a missense mutation. In a specific embodiment, techniques described herein or otherwise known in the art, are used to effect a “knockout” of the invention in humans, as part of a gene therapy protocol.
A replacement-type targeting vector, which can be used to create a knockout model, can be constructed using an isogenic genomic clone, for example, from a mouse strain such as 129/Sv (Stratagene Inc., LaJolla, Calif). The targeting vector can be introduced into a suitably-derived line of embryonic stem (ES) cells by electroporation to generate ES cell lines that carry a profoundly truncated form of a TAT-001 gene. To generate chimeric founder mice, the targeted cell lines are injected into a mouse blastula-stage embryo. Heterozygous offspring can be interbred to homozygosity. TAT-001 knockout mice provide a tool for studying the role of TAT-001 in disease such as cancer. Moreover, such mice provide the means, in vivo, for testing therapeutic compounds for amelioration of diseases or conditions involving a TAT-001-dependent or TAT-001-affected pathway.
A mutant TAT-001 nucleic acid encoding a non-functional polynucleotide of the invention (or a completely unrelated DNA sequence) flanked by DNA homologous to the endogenous gene (either the coding regions or regulatory regions of the gene) can be used, with or without a selectable marker and/or a negative selectable marker, to transfect cells that express polypeptides of the invention in vivo. In another embodiment, techniques known in the art are used to generate knockouts in cells that contain, but do not express the gene of interest. Insertion of the DNA construct, via targeted homologous recombination, results in inactivation of the targeted gene. Such approaches are particularly suited in research and agricultural fields where modifications to embryonic stem cells can be used to generate animal offspring with an inactive targeted gene (e.g., see Thomas and Capecchi (1987) and Thompson (1989), supra). This approach may be routinely adapted for use in humans provided the recombinant DNA constructs are directly administered or targeted to the required site in vivo using appropriate viral vectors that will be apparent to those of skill in the art.
Cell lines for use under cell culture conditions may be derived from transgenic and knockout animal models by methods commonly known in the art.
In further embodiments of the invention, cells that are genetically engineered to express the polypeptides of the invention, or alternatively, that are genetically engineered not to express the polypeptides of the invention (e.g., knockouts) are administered to a patient in vivo. Such cells may be obtained from the patient (i.e., animal, including human) or an MHC compatible donor and can include, but are not limited to fibroblasts, bone marrow cells, blood cells (e.g., lymphocytes), adipocytes, muscle cells, endothelial cells etc. The cells are genetically engineered in vitro using recombinant DNA techniques to introduce the coding sequence of polypeptides of the invention into the cells, or alternatively, to disrupt the coding sequence and/or endogenous regulatory sequence associated with the polypeptides of the invention. Methods used to genetically engineer the cells include transduction using viral vectors, and preferably vectors that integrate the transgene into the cell genome or transfection procedures, including, but not limited to, the use of plasmids, cosmids, YACs, naked DNA, electroporation, liposomes, etc. The coding sequence of the polypeptides of the invention can be placed under the control of a strong constitutive or inducible promoter or promoter/enhancer to achieve expression, and preferably secretion, of the polypeptides of the invention. The engineered cells which express and preferably secrete the polypeptides of the invention can be introduced into the patient systemically, for example in the circulation or intraperitoneally. Such cells may be used, for example, to generate an immune response in the host to the polypeptide, or to titrate off porteins or compounds that bind to the polypeptide. Knock-out cells may be useful, for example, as a control.
Alternatively, the cells can be incorporated into a matrix and implanted in the body. For example, genetically engineered fibroblasts can be implanted as part of a skin graft or genetically engineered endothelial cells can be implanted as part of a lymphatic or vascular graft. (See, for example, U.S. Pat. Nos. 5,399,346 and 5,460,959).
When the cells to be administered are non-autologous or non-MHC compatible cells, they can be administered using well known techniques which prevent the development of a host immune response against the introduced cells. For example, the cells may be introduced in an encapsulated form which, while allowing for an exchange of components with the immediate extracellular environment, does not allow the introduced cells to be recognized by the host immune system.
Transgenic and “knock-out” animals of the invention and tissues, organs, cell lines, and the like derived therefrom have uses which include, but are not limited to, animal model systems useful in elaborating the biological function of polypeptides of the present invention, studying diseases, disorders, and/or conditions associated with aberrant expression of TAT-001. Animal model systems are also useful for screening for compounds effective in ameliorating such diseases, disorders, and/or conditions.
Immunotherapy
As discussed below, TAT-001 nucleic acids and TAT-001 polypeptides are of use in an immunotherapeutic approach to proliferative discorders (e.g., cancer). In some embodiments, immunotherapy may be active immunotherapy (e.g., vaccines), in which treatment relies on the in vivo stimulation of the endogenous host immune system to react against tumors with the administration of immune response-modifying agents (such as TAT-001 polypeptides, TAT-001 nucleic acids, or effector cells). In other embodiments, immunotherapy may be passive immunotherapy, in which treatment involves the delivery of agents with established tumor-immune reactivity (e.g., effector cells or antibodies) that can directly or indirectly mediate antitumor effects and do not necessarily depend on an intact host immune system.
Examples of effector cells include T cells, T lymphocytes (e.g., CD8+ cytotoxic T lymphocytes and CD4+ T-helper tumor-infiltrating lymphocytes), killer cells (e.g., natural killer cells and lymphokine-activated killer cells), B cells, and other antigen-presenting cells (e.g., dendritic cells and macrophages (in various parts of the body, the macrophage may be referred to as alveolar cells (lungs); mesangial cells (kidneys); microglial cells (brain); Kupffer cells (liver); and dendritic Langerhans cells (skin))), expressing, presenting, or contacted with a TAT-001 polypeptide provided herein.
Effector cells may generally be obtained in sufficient quantities for adoptive immunotherapy by growth in vitro. Culture conditions for expanding single antigen-specific effector cells to several billion in number with retention of antigen recognition in vivo are well known in the art. Such in vitro culture conditions typically use intermittent stimulation with antigen, often in the presence of cytokines (such as IL-2) and non-dividing feeder cells. As noted above, immunoreactive TAT-001 polypeptides may be used to rapidly expand antigen-specific T cell cultures in order to generate a sufficient number of cells for immunotherapy. In particular, antigen-presenting cells, such as dendritic, macrophage, monocyte, fibroblast and/or B cells, may be pulsed with immunogenic polypeptides or transfected with one or more polynucleotides using standard techniques well known in the art. For example, antigen-presenting cells can be transfected with a polynucleotide having a promoter appropriate for increasing expression in a recombinant virus or other expression system. Cultured effector cells for use in therapy must be able to grow and distribute widely, and to survive long term in vivo. Studies have shown that cultured effector cells can be induced to grow in vivo and to survive long term in substantial numbers by repeated stimulation with antigen supplemented with IL-2 (see, for example, Cheever et al. (1997) Immunol Rev. 157: 177-194).
In one embodiment, autologous dendritic cells are pulsed with TAT-001 polypeptides capable of binding to MHC molecules (as may be determined using methods known in the art, for example, sequence analysis for MHC allele-binding motifs—the peptide motifs for a number of alleles, though not for all known alleles, have been assembled in a small number of publicly available databases (Rammensee et al. (1999) Immunogenetics. 50: 213-219). In another embodiment, dendritic cells are pulsed with the complete TAT-001 protein. Yet another embodiment involves engineering the overexpression of the TAT-001 gene in dendritic cells using various implementing vectors known in the art, such as adenovirus (Arthur et al. (1997) Cancer Gene Ther. 4: 17-25), retrovirus (Henderson et al. (1996) Cancer Res. 56: 3763-3770), lentivirus, adeno-associated virus, DNA transfection (Ribas et al. (1997) Cancer Res. 57: 2865-2869), and tumor-derived RNA transfection (Ashley et al. (1997) J Exp Med. 186: 1177-1182).
Particularly, the invention also encompasses the use of an antigen encoded by a TAT-001 nucleic acid. It is anticipated that these antigens may be used as therapeutic or prophylactic anti-cancer vaccines, and thus as anti-cancer agents. For example, a particular contemplated application of these antigens involves their administration with adjuvants that induce a cytotoxic T lymphocyte response. An especially preferred adjuvant is disclosed in U.S. Pat. Nos. 5,709,860; 5,695,770; and 5,585,103, incorporated herein by reference. Also, administration of the subject novel antigens in combination with an adjuvant may result in a humoral immune response against such antigens, thereby delaying or preventing the development of a cancer, such as colon cancer.
Alternatively, a vector expressing a TAT-001 polypeptide may be introduced into antigen presenting cells taken from a patient and clonally propagated ex vivo for transplant back into the same patient. Transfected cells may be reintroduced into the patient using any means known in the art, preferably in sterile form by intravenous, intracavitary, intraperitoneal or intratumor administration.
T cell receptors and antibody receptors specific for TAT-001 polypeptides may be cloned, expressed and transferred into other vectors or effector cells for adoptive immunotherapy. TAT-001 polypeptides provided herein may also be used to generate antibodies or anti-idiotypic antibodies (as herein and in U.S. Pat. No. 4,918,164) for passive immunotherapy.
Thus, the invention also provides a method of inducing an immune response to a TAT-001 polypeptide that includes providing a TAT-001 polypeptide that comprises at least one T cell antigen or at least one B cell antigen or at least one antigen presenting cell antigen; and, contacting the antigen with an immune system T cell or B cell or antigen presenting cell respectively, whereby an immune response is induced. Within the scope of this method, the polypeptide may be accompanied by an adjuvant, and within the scope of “contacting” the antigen may be made available to antigen presenting cells by the embodiments described above.
Vaccines
As already noted, a further aspect of the invention relates to a vaccine composition of use in the treatment of cancer. Thus, a TAT-001 polypeptide or TAT-001 nucleic acid may be useful as antigenic material, and may be used in the production of vaccines for treatment or prophylaxis of cancer. Such material can be “antigenic” and/or “immunogenic”. Generally, “antigenic” is taken to mean that the protein or nucleic acid is capable of being used to raise antibodies or indeed is capable of inducing an antibody response in a subject. “Immunogenic” is taken to mean that the protein or nucleic acid is capable of inducing a protective immune response in a subject. Thus, in the latter case, the TAT-001 polypeptide or TAT-001 nucleic acid may be capable of not only generating an antibody response but also non-antibody-based immune responses. This distinction, particularly as data supporting categorization of certain antibodies in this way is not readily available, is not always used and frequently the two terms are used interchangeably.
The invention further involves the identification of human patients for administration of a TAT-001 vaccine. A TAT-001 vaccine of the invention may be administered to uninfected individuals as a prophylactic therapy or to individuals diagnosed with a neoplasm (e.g., colon cancer). Individuals selected for prophylactic administration of recombinant TAT-001 include any individual at risk of developing a neoplasm as based upon age, sex, geographical location, or the presence of a condition which renders the individual susceptible to a neoplasm (e.g., colon cancer). Individuals at particularly high risk of developing colon cancer, or who would be most severely affected by such a cancer, include men and women over the age of 50, individuals with a tendency to develop polyps or a family history of the disease, and individuals who have previously had colon cancer. Individuals who may receive the recombinant TAT-001 vaccine as a therapeutic include those individuals with symptoms of colon cancer. The clinical symptoms associated with colon cancer include: pain in the lower abdominal area, diarrhea lasting more than several days, obstruction of bowel movements, iron deficiency anemia which may indicate bleeding in the colon, blood in the. stool, significant weight loss, abdominal mass or hardness in the abdomen, significant change in bowel habits, appendix pain, abdomen infection with pain and swelling which may indicate bowel perforation, and other appropriate symptoms or indicators such as positive tests for tumor markers, positive biopsies, positive imaging results (PET-scan, MRI, X-ray, etc.).
Individuals who have a neoplasm such as colorectal cancer may also be treated by administration of a vaccine of the invention, preferably in an immunogenically effective amount. Colon cancer disorders include any disease or other disorder of the gastrointestinal tract of a human or other mammal. Gastrointestinal neoplastic disorders include, for example, familial juvenile polyposis, gastrointestinal stromal tumors, familial adenomatous polyposis, hereditary non-polyposis colorectal cancer, colon cancer, rectal cancer, anal cancer, upper gastrointestinal cancer, gastrointestinal sarcomas, Peutz-Jeghers Syndrome, Cowden's syndrome, dysplasia, hyperplasia, neoplasia, and metastatses of colon cancer origin. Alternatively, it may be desirable to administer the vaccine to asymptomatic individuals, particularly where the individual may be susceptible to a neoplasm.
TAT-001 polypeptides of the invention and mixtures and combinations thereof may be useful as active components of vaccines capable of inducing a prophylactic or therapeutically effective immune response against cancer. Routes of administration, antigen doses, number and frequency of injections will vary from species to species and may parallel those currently being used in the clinic and/or experimentally to provide immunity or therapy against other diseases or cancer. For example, the vaccines are pharmaceutically acceptable compositions containing one or more of the TAT-001 polypeptides of this invention, its analogues or mixtures or combinations thereof, in an amount effective in the mammal, including a human, treated with that composition to raise immunity sufficient to protect the treated mammal from cancer for a period of time. It is also possible that TAT-001-specific immunity prompted by immunization with TAT-001 polypeptides or related compounds are useful to favor the degradation of TAT-001 or alleviate manifestations of the disease without affecting the expression or function of TAT-001 in other tissues, resulting in improvement of clinical status in clinically symptomatic humans with cancer.
Different types of vaccines can be developed according to standard procedures known in the art. For example, a vaccine may be peptide-based, nucleic acid-based, bacterial- or viral-based vaccines. A vaccine formulation containing at least one TAT-001 polypeptide or nucleic acid may contain a variety of other components, including stabilizers, flavor enhancers (e.g., sugar). The vaccine also optionally comprises or is co-administered with one or more suitable adjuvants, such as a mucosal adjuvant. The mucosal adjuvant may be any known in the art appropriate for human use (e.g., cholera toxin (CT), enterotoxigenic E. coli heat-labile toxin (LT), or a derivative, subunit, or fragment of CT or LT which retains adjuvanticity). The mucosal adjuvant is co-administered with TAT-001 vaccine in an amount effective to induce or enhance a mucosal immune response, particularly a humoral and/or a mucosal immune response. The ratio of adjuvant to TAT-001 vaccine may be determined by standard methods by one skilled in the art. Preferably, the adjuvant is present at a ratio of 1 part adjuvant to 10 parts TAT-001 vaccine.
In another embodiment, peptide vaccines may utilize peptides corresponding to a TAT-001-specific epitope or finctional derivatives thereof can be utilized as a prophylactic or therapeutic vaccine in a number of ways, including: 1) as monomers or multimers of the same sequence, 2) combined contiguously or non-contiguously with additional sequences that may facilitate aggregation, promote presentation or processing of the epitope (e.g., class I/II targeting sequences) and/or additional antibody, T helper or CTL epitopes to increase the immunogenicity of the TAT-001-specific epitope as a means to enhance efficacy of the vaccine, 3) chemically modified or conjugated to agents that would increase the immunogenicity or delivery of the vaccine (e.g., fatty acid or acyl chains, KLH, tetanus toxoid, or cholera toxin), 4) any combination of the above, 5) any of the above in combination with adjuvants, including but not limited to inorganic gels such as aluminium hydroxide, and water-in-oil emulsions such as incomplete Freund's adjuvant, aluminum salts, saponins or triterpenes, MPL, cholera toxin, ISCOM'S®, PROVAX®, DETOX®, SAF, Freund's adjuvant, Alum®, Saponin®, among others, and particularly those described in in U.S. Pat. Nos. 5,709,860; 5,695,770; and 5,585,103; and/or delivery vehicles, including but not limited to liposomes, VPLs or virus-like particles, microemulsions, attenuated or killed bacterial and viral vectors, and degradable microspheres (see e.g., Kersten and Hirschberg (2004) Expert Rev of Vaccines. 3: 453-462; Sheikh et al. (2000) Curr Opin Mol Ther. 2: 37-54), and 6) administered by any route or as a means to load cells with antigen ex vivo.
Examples of these nucleic-acid based vaccines as a prophylactic or a therapeutic include: 1) any nucleic acid encoding the expression (transcription and/or translation) of TAT-001-specific epitope, 2) additional nucleic acid sequences that facilitate processing and presentation, aggregation, secretion, targeting (to a particular cell type) of a TAT-001-specific epitope, either translational fusions or independent transcriptional units, 3) additional nucleic acid sequences that function as adjuvants/imniunomodulators, either translational fusions or independent transcriptional units, 4) additional antibody, T helper or CTL epitopes that increase the immunogenicity of a TAT-001-specific epitope or efficacy of the vaccine, either translational fusions or independent, and 5) any combination of the above, 6) the above administered in saline (‘naked’ DNA) or in combination with an adjuvant(s), (e.g., aluminum salts, QS-21, MPL), immunomodulatory agent(s) (e.g., rIL-2, rGM-CSF, rIL-12), and/or nucleic acid delivery agents (e.g., polymer-, lipid-, peptide-based, degradable particles, microemulsions, VPLs, attenuated bacterial or viral vectors) using any route or ex vivo loading.
The process for formulation of a TAT-001 vaccine involves standard methods known in the art. Attenuated or killed bacterial or viral vectors can be used to deliver either the antigen or DNA/RNA that codes for the expression of the antigen. These can also be used as a means to load cells with antigen ex vivo. Or, for example, use of liposomes or microspheres (see Kersten and Hirschberg (2004) supra for review). A TAT-001 polypeptide is administered, for example, to a mucosal surface of the individual in order to stimulate a mucosal immune response effective to provide protection from a colon carcinoma (see for example U.S. Pat. Nos. 6,126,938 and 6,630,455). Preferably, at least one TAT-001 polypeptide is administered so as to induce a mucosal immune response associated with production of anti-TAT-001 IgA antibodies and/or infiltration of lymphocytes into the gastric mucosa. The TAT-001 may be administered to any mucosal surface of the patient. Preferable mucosal surfaces are intranasal or oral. Vaccines are prepared according to standard methods known in the art, and will be readily applicable to any new or improved method for vaccine production.
Thus, in a further aspect, the present invention provides the use of a TAT-001 polypeptide or a TAT-001 nucleic acid in the production of a pharmaceutical composition for the treatment or prophylaxis of cancer, wherein the composition is a vaccine. For prophylactic therapy, a vaccine containing at least one TAT-001 polypeptide may be administered at any time prior to contact with, or establishment of, a colon carcinoma.
Dosages of a TAT-001 vaccine administered to the individual as either a prophylactic therapy or an antineoplastic therapy can be determined by one skilled in the art. Generally, dosages will contain between about 10 μg to 1,000 mg, preferably between about 10 mg and 500 mg, more preferably between about 30 mg and 120 mg, more preferably between about 40 mg and 70 mg, most preferably about 60 mg of a TAT-001 vaccine.
At least one dose of a TAT-001 vaccine will be administered to the patient, preferably at least two doses, more preferably four doses, with up to six or more total doses administered. It may be desirable to administer booster doses of a TAT-001 vaccine at one or two week intervals after the last immunization, generally one booster dose containing less than, or the same amount of, a TAT-001 vaccine as the initial dose administered. Most preferably, the vaccine regimen will be administered in four doses at one week intervals. Since a polypeptide or a nucleic acid may be broken down in the stomach, the vaccine composition is preferably administered parenterally (e.g., subcutaneous, intramuscular, intravenous, or intradermal injection). The progress of immunized patients may be followed by general medical evaluation, screening for infection by serology and/or gastroscopic examination.
Antibodies
The invention preferably includes the preparation and use of anti-TAT-001 antibodies and fragments for use as diagnostics and therapeutics. The unique ability of antibodies to recognize and specifically bind to target proteins provides approaches for both diagnosing and treating a cancer characterized by overexpression of one or more TAT-001 polypeptides. Thus, another aspect of the present invention provides for a method for preventing or treating diseases (e.g., cancer) involving overexpression of TAT-001 by treatment of a patient with antibodies that specifically bind to TAT-001 protein. To this end, the invention provides antibodies that bind to TAT-001 polypeptides and fragments thereof, including, but not limited to, polyclonal and monoclonal antibodies, anti-idiotypic antibodies, murine and other mammalian antibodies, antibody fragments, bispecific antibodies, antibody dimers or tetramers, single chain antibodies (e.g., scFv's and antigen-binding antibody fragments such as Fabs, 2 Fabs, and Fab′ fragments), recombinant binding regions based on antibody binding regions, chimeric antibodies, primatized antibodies, humanized and fully human antibodies, domain deleted antibodies, and antibodies labeled with a detectable marker, or coupled with a toxin or radionucleide. Such antibodies can be produced by conventional methods. However, the preferred embodiment of the invention will comprise the preparation of monoclonal antibodies or antibody fragments against the antigens encoded by TAT-001 nucleic acids, preferably those encoded by SEQ ID NO: 6 or 9. Accordingly, a TAT-001 polypeptide may be used as an immunogen to generate antibodies.
Thus, if an antibody molecule that specifically binds a particular TAT-001 antigen is desired, particularly should one not be otherwise available (or a source for a cDNA library for cloning a nucleic acid encoding such an antibody), antibodies specific for the particular antigen may be generated by any suitable method known in the art, examples of which are discussed below. In one example, murine or human monoclonal antibodies can be produced through recombinant methods by hybridoma technology, preferably in eukaryotic cells. In another example, the protein, or an immunologically active fragment thereof, or an anti-idiotypic antibody, or fragment thereof can be administered to an animal to induce the production of antibodies capable of recognizing and binding to the protein. Genetic immunization can be carried out by injecting the animals with cDNA encoding the target protein, obviating the need to prepare a protein or peptide immunogen. In general, antibody generation will comprise immunization of an appropriate (generally non-homologous) host with the desired TAT-001 polypeptide(s) or TAT-001 nucleic acid(s) (collectively TAT-001 antigens, though preferentially this term refers to TAT-001 polypeptides, most preferably the peptides of SEQ ID NO: 1 and 3 and/or the protein of SEQ ID NO: 5 or SEQ ID NO: 8). Specific antibodies or fluids, tissues, organs or cells containing them may be isolated from the host for purification or use in unpurified form, such as rabbit sera. Or, in a preferered embodiment, the isolation of immune cells therefrom, use of such immune cells to make hybridomas, and screening for monoclonal antibodies that specifically bind to a TAT-001 polypeptide will be carried out. Such antibodies can be from any class of antibodies including, but not limited to IgG, IgA, IgM, IgD, and IgE or in the case of avian species, IgY and from any subclass of antibodies.
Most preferred are antibodies that bind specifically to one or more TAT-001 polypeptides. In one embodiment, antibodies may be used to inhibit the activity of the TAT-001 polypeptides, and/or to target therapeutic agents (e.g., radionucleides or an immune response) to a tumor. Preferably, such antibodies will bind TAT-001 antigens with high affinity, e.g., possess a binding affinity (Kd) on the order of 10−6 to 10−12 M or greater, preferably at least 10−6, at least 10−7, more preferably at least 10−8, at least 10−9, at least 10−10, most preferably at least 10−11, at least 10−12, or greater.
i.) Polyclonals
Polyclonal antibodies can be prepared by immunizing rabbits or other animals by injecting antigen followed by subsequent boosts at appropriate intervals. The animals are bled and sera assayed against purified protein usually by ELISA or by bioassay based upon the ability to block the action of the corresponding gene. When using avian species, e.g., chicken, turkey and the like, the antibody can be isolated from the yolk of the egg.
Polyclonal antibodies to TAT-001 antigens can be raised in animals by multiple subcutaneous (sc) or intraperitoneal (ip) injections of the antigen and an adjuvant. It may be useful to conjugate the antigen or a fragment containing the target amino acid sequence to a protein that is immunogenic in the species to be immunized (e.g., keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin, or soybean trypsin inhibitor) using a bifinctional or derivatizing agent (e.g., maleimidobenzoyl sulfosuccinimide ester (conjugation through cysteine residues), N-hydroxysuccinimide (through lysine residues), glutaraldehyde, or succinic anhydride).
For example, animals can be immunized against the TAT-001 polypeptide or fragment thereof, immunogenic conjugates, or derivatives by combining 1 μg to 1 mg of the peptide or conjugate (for rabbits or mice, respectively) with 3 volumes of Freund's complete adjuvant and injecting the solution intradermally at multiple sites. One month later the animals are boosted with ⅕ to 1/10 the original amount of peptide or conjugate in Freund's complete adjuvant by subcutaneous injection at multiple sites. Seven to 14 days later the animals are bled and the serum is assayed for antibody titer to the antigen or a fragment thereof. Animals are boosted until the titer plateaus. Preferably, the animal is boosted with the conjugate of the same polypeptide or another TAT-001 polypeptide or fragment thereof, but conjugated to a different protein and/or through a different cross-linking reagent. Conjugates also can be made in recombinant cell culture as protein fusions. Also, aggregating agents such as alum are suitably used to enhance the immune response.
Chimeric, humanized, or fully human polyclonals may be produced in animals transgenic for human immunoglobulin genes, or by isolating two or more TAT-001 reactive B-lymphocytes from a patient for starting material.
Polyclonals may also be purified and selected for (such as through affinity for a conformationally constrained antigen peptide), iteratively if necessary, to provide a monoclonal antibody. Alternatively or additionally, cloning out the nucleic acid encoding a single antibody from a lymphocyte may be employed.
ii.) Monoclonals
In a preferred embodiment of the invention, monoclonal antibodies are obtained from a population of substantially homogeneous antibodies (i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts). Thus, the modifier “monoclonal” indicates the character of the antibody as not being a mixture of discrete antibodies.
Monoclonal antibodies can be prepared by methods known in the art, such as the hybridoma method of Kohler and Milstein by fusing splenocytes from immunized mice with continuously replicating tumor cells such as myeloma or lymphoma cells. (Kohler and Milstein (1975) Nature 256: 495-497; Gulfre and Milstein (1981) Methods in Enzymology: Immunochemical Techniques 73: 1-46, Langone and Banatis eds., Academic Press). The hybridoma cells are then cloned by limiting dilution methods and supernates assayed for antibody production by ELISA, RIA or bioassay. In another embodiment, monoclonals may be made by recombinant DNA methods.
For preparation of monoclonal antibodies (mAbs) directed toward a TAT-001 polypeptide, any technique which provides for the production of antibody molecules by continuous cell lines in culture may be used. For example, the hybridoma technique originally developed by Kohler and Milstein ((1975) supra, as well as in Kohler and Milstein (1976) Eur J Immunol. 6: 511-519; Kohler et al. (1976) Eur J Immunol. 6: 292 -295; Hamrnerling et al. (1981) in: Monoclonal Antibodies and T-Cell Hybridomas, Elsevier, N.Y., pp. 563-681), and the trioma technique, the human B-cell hybridoma technique (Kozbor et al. (1983) Immunol Today. 4: 72-79), and the EBV-hybridoma technique to produce human monoclonal antibodies (Cole et al. (1985) in Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp. 77-96). Such antibodies may be of any immunoglobulin class including IgG, IgM, IgE, IgA, IgD and any subclass thereof. The hybridoma producing the mAbs in the invention may be cultivated in vitro or in vivo. In an additional embodiment of the invention, monoclonal antibodies can be produced in germ-free animals utilizing technology known in the art.
In general, a mouse or other appropriate host animal, such as a hamster, is immunized with a TAT-001 polypeptide(s), or, more preferably, with a secreted TAT-001 polypeptide-expressing cell to induce lymphocytes that produce or are capable of producing antibodies that will specifically bind to the antigen or fragment.thereof used for immunization. Alternatively, lymphocytes are immunized in vitro. TAT-001 polypeptide-expressing cells may be cultured in any suitable tissue culture medium, preferably in Earle's modified Eagle's medium supplemented with 10% fetal bovine serum (inactivated at about 56° C.), and supplemented with about 10 g/l of nonessential amino acids, about 1,000 U/ml of penicillin, and about 100 μg/ml of streptomycin.
The splenocytes of the immunized host animal (e.g., a mouse) are extracted and fused with a suitable myeloma cell line using a suitable fusing agent, such as polyethylene glycol, to form a hybridoma cell (Goding (1986) Monoclonal Antibodies: Principles and Practice, pp. 59-103, Academic Press). Any suitable myeloma cell line may be employed in accordance with the present invention; however, preferred myeloma cells are those that fuse efficiently, support stable high-level production of antibody by the selected antibody-producing cells, and are sensitive to a medium such as HAT medium. Among these, preferred myeloma cell lines are murine myeloma lines, such as those derived from MOPC-21 and MPC-11 mouse tumors available from the Salk Institute Cell Distribution Center, San Diego, Calif. USA, and SP-2 cells available from the American Type Culture Collection, Rockville, Md. USA.
The hybridoma cells thus prepared may be seeded and grown in a suitable culture medium that preferably contains one or more substances that inhibit the growth or survival of the unfused, parental myeloma cells. For example, if the parental myeloma cells lack the enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT or HPRT), the culture medium for the hybridomas typically will include hypoxanthine, aminopterin, and thymidine (HAT medium), which prevent the growth of HGPRT-deficient cells. The hybridoma cells may be cloned by limiting dilution as described by Wands et al. ((1981) Gastroenterology 80: 225-232). The hybridoma cells obtained through such a selection and/or culture medium in which the hybridoma cells are being maintained can then be assayed to identify production of monoclonal antibodies directed against a TAT-001 antigen. Preferably, the binding specificity of monoclonal antibodies produced by hybridoma cells is determined by immunoprecipitation or by an in vitro binding assay, such as radioimmunoassay (RIA) or enzyme-linked immunoabsorbent assay (ELISA). The binding affinity of the monoclonal antibody can, for example, be determined by the Scatchard analysis of Munson and Rodbard (1980) Anal Biochem. 107: 220-239.
After hybridoma cells are identified that produce antibodies of the desired specificity, affinity, and/or activity, the clones may be subcloned by limiting dilution procedures and grown by standard methods (Goding, supra). Suitable culture media for this purpose include, for example, D-MEM or RPMI-1640 medium. In addition, the hybridoma cells may be grown in vivo as ascites tumors in an animal.
The monoclonal antibodies secreted by the subclones are suitably separated from the culture medium, ascites fluid, or serum by conventional immunoglobulin purification procedures such as, for example, protein A-Sepharose, hydroxyapatite chromatography, gel electrophoresis, dialysis, or affinity chromatography.
DNA encoding the monoclonal antibodies of the invention is readily isolated and sequenced using conventional procedures (e.g., using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of murine antibodies). The hybridoma cells of the invention serve as a preferred source of such DNA. Once isolated, the DNA may be placed into expression vectors, which are then transfected into host cells such as E. coli cells, COS cells, Chinese hamster ovary (CHO) cells, or myeloma cells that do not otherwise produce immunoglobulin protein, to obtain the synthesis of monoclonal antibodies in the recombinant host cells (see e.g., Skerra et al. (1993) Curr Opin Immunol. 5: 256-262 and Pluckthun (1992) Immunol Rev. 130: 151-188). A preferred expression system is the NEOSPLA expression system (Biogen-IDEC).
The DNA also may be modified, for example, by substituting all or part of the coding sequence for human heavy- and light-chain constant domains in place of the homologous murine sequences (Morrison et al. (1984) Proc Natl Acad Sci. U.S.A. 81: 6851-6855), or by covalently joining to the immunoglobulin coding sequence all or part of the coding sequence for a non- immunoglobulin polypeptide. In that manner, “chimeric” or “hybrid” antibodies are prepared that have the binding specificity of an anti-TAT-001 antigen monoclonal antibody.
Typically such non-immunoglobulin polypeptides are substituted for the constant domains of an antibody of the invention, or they are substituted for the variable domains of one antigen-combining site of an antibody of the invention to create a chimeric bivalent antibody comprising one antigen-combining site having specificity for a TAT-001 antigen according to the invention and another antigen-combining site having specificity for a different antigen.
Chimeric or hybrid antibodies also may be prepared in vitro using known methods in synthetic protein chemistry, including those involving crosslinking agents. For example, immunotoxins may be constructed using a disulfide-exchange reaction or by forming a thioether bond. Examples of suitable reagents for this purpose include iminothiolate and methyl-4-mercaptobutyrimidate.
The antibodies in the present invention can also be generated using various phage display methods known in the art where functional antibody domains are displayed on the surface of phage particles carrying the polynucleotide sequences encoding them. In a particular embodiment, such phage can be utilized to display antigen binding domains expressed from a repertoire or combinatorial antibody library (e.g., human or murine). Phage expressing an antigen binding domain that binds the antigen of interest can be selected or identified with antigen, for example, using labelled antigen or antigen bound or captured to a solid surface or bead. Phage used in these methods are typically filamentous phage including fd and M13 binding domains expressed from phage with Fab, Fv or disulphide stabilized Fv antibody domains recombinantly fused to either the phage gene III or gene VIII protein. Phage display methods that can be used to make the antibodies of the present invention include those disclosed in Brinkman et al. (1995) J Immunol Meth. 182: 41-50; Ames et al. (1995) J Immunol Meth. 184: 177-186; Kettleborough et al. (1994) Eur J Immunol. 24: 952-958; Persic et al. (1997) Gene. 187: 9-18; Burton et aL. (1994) Adv Immunol. 57: 191-280; European Publication No. EP 05 89877; PCT Publication Nos. WO 90/02809; WO 91/10737; WO 92/01047; WO 92/18619; WO 93/11236; WO 95/15982; WO 95/20401; and U.S. Pat. Nos. 5,698,426; 5,223,409; 5,403,484; 5,580,717; 5,427,908; 5,750,753; 5,821,047; 5,571,698; 5,427,908; 5,516,637; 5,780,225; 5,658,727; 5,733,743 and 5,969,108.
As described in the above references, after phage selection, the antibody coding regions from the phage can be isolated and used to generate whole antibodies, including human antibodies, or any other desired antigen binding fragment, and expressed in any desired host, including mammalian cells, insect cells, plant cells, yeast, and bacteria, for example, as described in detail below. For example, techniques to recombinantly produce Fab, Fab′ and F(ab′)2 fragments can also be employed using methods known in the art such as those disclosed in WO 92/22324; Mullinax et al. (1992) Biotechniques. 12: 864-869; and Sawai et al. (1995) AJRI 34: 26-34; and Better et al. (1988) Science 240: 1041-1043.
Alternatively, additional antibodies capable of binding polypeptide(s) of the invention can be produced in a two-step procedure using anti-idiotypic antibodies. Exemplary methods for making anti-idiotypic antibodies may be found in, Asai (Ed.) (1993) Antibodies in Cell Biology. Methods in Cell Biology, Vol. 37, Academic Press, and U.S. Pat. No. 5,270,202, incorporated herein by reference. This method uses the fact that antibodies are themselves antigens, and therefore, it is possible to obtain an antibody which binds to a second antibody. In accordance with this method, protein specific antibodies are used to immunize an animal, preferably a mouse. The splenocytes of such an animal are then used to produce hybridoma cells, and the hybridoma cells are screened to identify clones which produce an antibody whose ability to bind to the polypeptide(s) of the invention protein-specific antibody can be blocked by polypeptide(s) of the invention. Such antibodies comprise anti-idiotypic antibodies to the polypeptide(s) of the invention protein-specific antibody and are used to immunize an animal to induce formation of further polypeptide(s) of the invention protein-specific antibodies.
iii.) Chimeric, Humanized, Primatized, Fully Human
Monoclonal antibodies of the invention include, but are not limited to, human monoclonal antibodies, primatized monoclonal antibodies, and chimeric monoclonal antibodies (for example, human-mouse chimeras). A chimeric antibody is a molecule in which different portions are derived from different animal species, such as those having a human immunoglobulin constant region and a variable region derived from a murine mAb (see e.g., U.S. Pat. Nos. 4,816,567 and 4,816,397). Humanized forms of non-human (e.g., murine) antibodies are chimeric immunoglobulins, immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab′, F(ab′)2 or other antigen-binding subsequences of antibodies) which contain minimal sequence derived from non-human immunoglobulin, such as one or more complementarity determining regions (CDRs) from the non-human species and a framework region from a human immunoglobulin molecule (see e.g., U.S. Pat. No. 5,585,089).
Humanized antibodies include human immunoglobulins (recipient antibody) in which residues from a complementary-determining region (CDR) of the recipient are replaced by residues from a CDR of a non-human species (donor antibody) such as mouse, rat or rabbit having the desired specificity, affinity and capacity. In some instances, Fv framework residues of the human immunoglobulin are replaced by corresponding non-human residues. Humanized antibodies may also comprise residues which are found neither in the recipient antibody nor in the imported CDR or framework sequences. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin, and all or substantially all of the FR regions are those of a human immunoglobulin consensus sequence. The humanized antibody optimally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin.
Chimeric and humanized monoclonal antibodies can be produced by recombinant DNA techniques known in the art, for example using methods described in WO 87/02671; EP 184,187; EP 171,496; EP 173,494; WO 86/01533; U.S. Pat. No. 4,816,567; EP 125,023; Better et al. (1988) Science 240: 1041-1043; Liu et al. (1987) Proc Natl Acad Sci. U.S.A. 84: 3439-3443; Liu et al. (1987) J Immunol. 139: 3521-3526; Sun et al. (1987) Proc Natl Acad Sci. U.S.A. 84: 214-218; Nishimura et al. (1987) Cancer Res. 47: 999-1005; Wood et al. (1985) Nature 314: 446-449; Shaw et al. (1988) J Natl Cancer Inst. 80: 1553-1559; Morrison (1985) Science 229: 1202-1207; Oi et al. (1986) Biotechniques. 4: 214; US 5,225,539; Jones et al. (1986) Nature 321: 552-525; Verhoeyan et al. (1988) Science 239: 1534; and Beidler et al. (1988) J Immunol. 141: 4053-4060. See, below for a further discussion of humanized antibodies and methods related thereto.
Another highly efficient means for generating recombinant antibodies is disclosed by Newman ((1992) Biotechnology. 10: 1455-1460) incorporated herein by reference; see also U.S. Pat. Nos. 5,756,096; 5,750,105; 5,693,780; 5,681,722; and 5,658,570. More particularly, this technique results in the generation of primatized antibodies which contain monkey variable domains and human constant sequences.
This technique modifies antibodies such that they are not antigenically rejected upon administration in humans, and relies on immunization of cynomolgus monkeys with human antigens or receptors. The technique was developed to create high affinity monoclonal antibodies directed to human cell surface antigens.
Antibodies generated in this manner have previously been reported to display human effector function, have reduced immunogenicity, and long serum half-life. Cynomolgus monkeys, while phylogenetically similar to humans, still recognize many human proteins as foreign and therefore mount an immune response, but generate antibodies that have a high degree of amino acid homology to those produced in humans. Indeed, after sequencing macaque immunoglobulin light and heavy chain variable region genes, the sequence of each gene family was found to be 85-98% homologous to its human counterpart (Newman et al. (1992) supra). The first antibody generated in this way, an anti-CD4 antibody, was 91-92% homologous to the consensus sequence of human immunoglobulin framework regions (Newman et al. (1992) supra).
Methods for humanizing non-human antibodies are well known in the art. Generally, a humanized antibody has one or more amino acid residues introduced into it from a source which is non-human. These non-human amino acid residues are often referred to as “import” residues, which are typically taken from an “import” variable domain. Humanization may be essentially performed following the method of Winter and co-workers as described above (including Jones et al. (1986) Nature 321: 522-525; Riechmann et al. (1988) Nature 332: 323-327; Verhoeyen et al. (1988) Science 239: 1534-1536), by substituting rodent CDRs or CDR sequences for the corresponding sequences of a human antibody. Accordingly, such “humanized” antibodies are chimeric antibodies (U.S. Pat. Nos. 4,816,567 and 6,331,415), wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non- human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.
The choice of human variable domains, both light and heavy, to be used in making the humanized antibodies is very important to reduce antigenicity. According to the so-called “best-fit” method, the sequence of the variable domain of a rodent antibody is screened against the entire library of known human variable-domain sequences. The human sequence which is closest to that of the rodent is then accepted as the human framework (FR) for the humanized antibody (Sims et al. (1993) J Immunol. 151: 2296-2308; Chothia and Lesk (1987) J Mol Biol. 196: 901-917). Another method uses a particular framework derived from the consensus sequence of all human antibodies of a particular subgroup of light or heavy chains. The same framework may be used for several different humanized antibodies (Carter et al. (1992) Proc Natl Acad Sci. U.S.A. 89: 4285-4289; Presta et al. (1993) J Immunol. 151: 2623-2632). Another method may be found in US Pat. Publication No. 20030190705.
It is also desired that antibodies be humanized with retention of high affinity for the antigen and other favorable biological properties. To achieve this goal, according to a preferred method, humanized antibodies are prepared by a process of analysis of the parental sequences and various conceptual humanized products using three-dimensional models of the parental and humanized sequences. Three-dimensional immunoglobulin models are commonly available and are familiar to those skilled in the art. Computer programs are available which illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. Inspection of these displays permits analysis of the likely role of the residues in the finctioning of the candidate immunoglobulin sequence, i.e., the analysis of residues that influence the ability of the candidate immunoglobulin to bind its antigen. In this way, FR residues may be selected and combined from the consensus and import sequences so that the desired antibody characteristic, such as increased affinity for the target antigen(s), is achieved. In general, the CDR residues are directly and most substantially involved in influencing antigen binding.
Completely human antibodies are particularly desirable for therapeutic treatment of human patients. Such antibodies may be produced, for example, using transgenic mice which are incapable of expressing endogenous immunoglobulin heavy and light chain genes, but which can express human heavy and light chain genes. The transgenic mice may be immunized in the normal fashion with a selected antigen, e.g., all or a portion of a TAT-001 polypeptide. See for examples, PCT Publication Nos. WO 94/02602, WO 00/76310; U.S. Pat. Nos. 5,545,806; 5,545,807; 5,569,825; 6,150,584; 6,512,097; and 6,657,103; Jakobovits et al. (1993) Proc Natl Acad Sci. U.S.A. 90: 2551; Jakobovits et aL. (1993) Nature 362: 255-258; Bruggemann et al. (1993) Year in Immunol. 7: 33-40; Mendez et al. (1997) Nat Gene. 15: 146-156, and Green and Jakobovits (1998) J Exp Med. 188: 483-495.
Human monoclonal antibodies can also be made by the hybridoma method. Human myeloma and mouse-human heteromyeloma cell lines for the production of human monoclonal antibodies have been described, for example, by Kozbor (1984) J Immunol. 133: 3001-3005; Brodeur et aL. (1987) Monoclonal Antibody Production Techniques and Applications, pp.51-63, Marcel Dekker, Inc., New York; and Boemer et al. (1991) J Immunol. 147: 86-95.
Completely human antibodies which recognize a selected epitope can also be generated using a technique referred to as “guided selection.” In this approach, a selected non-human monoclonal antibody, e. g. a mouse antibody, is used to guide the selection of a completely human antibody recognizing the same epitope (Jespers et al. (1994) Biotechnology. 12: 899-903).
Alternatively, the phage display technology (McCafferty et al. (1990) Nature 348: 552-553) can be used to produce human antibodies and antibody fragments in vitro, from immunoglobulin variable (V) domain gene repertoires from non-immunized donors. According to this technique, antibody V domain genes are cloned in-frame into either a major or minor coat protein gene of a filamentous bacteriophage, such as Ml 3 or fd, and displayed as functional antibody fragments on the surface of the phage particle. Because the filamentous particle contains a single-stranded DNA copy of the phage genome, selections based on the functional properties of the antibody also result in selection of the gene encoding the antibody exhibiting those properties. Thus, the phage mimics some of the properties of the B-cell. Phage display can be performed in a variety of formats; for their review see, e.g., Johnson and Chiswell (1993) Curr Opin Struct Biol. 3: 564-571. Several sources of V-gene segments can be used for phage display. Clackson et al. (1991) Nature 352: 624-628 isolated a diverse array of anti-oxazolone antibodies from a small random combinatorial library of V genes derived from the spleens of immunized mice. A repertoire of V genes from non-immunized human donors can be constructed and antibodies to a diverse array of antigens (including self-antigens) can be isolated essentially following the techniques described by Marks et a. (1991) J Mol Biol. 222: 581-597, or Griffith et al. (1993) EMBO J. 12: 725-734.
In a natural immune response, antibody genes accumulate mutations at a high rate (somatic hypermutation). Some of the changes introduced will confer higher affinity, and B cells displaying high-affinity surface immunoglobulin are preferentially replicated and differentiated during subsequent antigen challenge. This natural process can be mimicked by employing the technique known as “chain shuffling” (Marks et al. (1992) Biotechnology 10: 779-783). In this method, the affinity of “primary” human antibodies obtained by phage display can be improved by sequentially replacing the heavy and light chain V region genes with repertoires of naturally occurring variants (repertoires) of V domain genes obtained from non-immunized donors. This technique allows the production of antibodies and antibody fragments with affinities in the nM range. A strategy for making very large phage antibody repertoires has been described by Waterhouse et al. (1993) Nucleic Acids Res. 21: 2265-2266.
Gene shuffling can also be used to derive human antibodies from rodent antibodies, where the human antibody has similar affinities and specificities to the starting rodent antibody. According to this method, also referred to as “epitope imprinting”, the heavy or light chain V domain gene of rodent antibodies obtained by phage display technique is replaced with a repertoire of human V domain genes, creating rodent-human chimeras. Selection on antigen results in isolation of human variable capable of restoring a functional antigen-binding site, i.e., the epitope governs (imprints) the choice of partner. When the process is repeated in order to replace the remaining rodent V domain, a human antibody is obtained (see WO 93/06213). Unlike traditional humanization of rodent antibodies by CDR grafting, this technique provides completely human antibodies, which have no framework or CDR residues of rodent origin.
Examples of techniques which can be used to produce single-chain Fvs and antibodies include those described in U.S. Pat. Nos. 4,946,778 and 5,258, 498; Huston et al. (1991) Meth Enzymol. 203: 46-88; Shu et al. (1993) Proc Natl Acad Sci. U.S.A. 90: 7995-7999; and Skerra et al. (1988) Science 240: 1038-1040.
iv.) Bispecific
The invention further provides bispecific antibodies, which can be made by methods known in the art. Bispecific antibodies are monoclonal, preferably human or humanized, antibodies that have binding specificities for at least two different antigens. Traditional production of full length bispecific antibodies is based on the coexpression of two immunoglobulin heavy chain-light chain pairs, where the two chains have different specificities (Milstein and Cuello (1983) Nature 305: 537-539). Because of the random assortment of immunoglobulin heavy and light chains, these hybridomas (quadromas) produce a potential mixture of 10 different antibody molecules, of which only one has the correct bispecific structure. Purification of the correct molecule, which is usually done by affinity chromatography steps, is rather cumbersome, and the product yields are low. Similar procedures are disclosed in WO 93/08829, and in Traunecker et al. (1991) EMBO J. 10: 3655-3659.
In another, more preferred, approach, antibody variable domains with the desired binding specificities (antibody-antigen combining sites) are fused to immunoglobulin constant domain sequences. The fusion preferably is with an immunoglobulin heavy chain constant domain, comprising at least part of the hinge, CH2, and CH3 regions. It is preferred to have the first heavy-chain constant region (CH1) containing the site necessary for light chain binding, present in at least one of the fusions. DNAs encoding the immunoglobulin heavy chain fusions and, if desired, the immunoglobulin light chain, are inserted into separate expression vectors, and are co-transfected into a suitable host organism. This provides for great flexibility in adjusting the mutual proportions of the three polypeptide fragments in embodiments when unequal ratios of the three polypeptide chains used in the construction provide the optimum yields. It is also possible to insert the coding sequences for two or all three polypeptide chains in one expression vector when the expression of at least two polypeptide chains in equal ratios results in high yields or when the ratios are of no particular significance.
In a preferred embodiment of this approach, the bispecific antibodies are composed of a hybrid immunoglobulin heavy chain with a first binding specificity in one arm, and a hybrid immunoglobulin heavy chain-light chain pair (providing a second binding specificity) in the other arm. This asymmetric structure facilitates the separation of the desired bispecific compound from unwanted immunoglobulin chain combinations, as the presence of an immunoglobulin light chain in only one half of the bispecific molecule allows facile separation. This approach is disclosed in WO 94/04690. For further details for generating bispecific antibodies see, for example, Suresh et al. ((1986) Meth Enzymol. 121: 210-228).
v.) Other
Heteroconjugate antibodies are also within the scope of the present invention. Heteroconjugate antibodies are composed of two covalently joined antibodies. Such antibodies can be, for example, diabodies, triabodies or tetrabodies. Such antibodies have, for example, been proposed to target immune system cells to unwanted cells (U.S. Pat. No. 4,676,980), and for treatment of HIV infection (WO 91/00360; WO 92/00373; and EP 03089). Heteroconjugate antibodies may be made using any convenient cross-linking methods. Suitable cross-linking agents are well known in the art, and are disclosed in U.S. Pat. No. 4,676,980, along with a number of cross-linking techniques.
In another preferred embodiment, multi-specific antibodies, fragments, and fuision proteins of the present invention, such as heteroconjugate antibodies, can be targeted against an antigens selected from the group of known immunotherapy targets consisting of CD2 (GenBank GI #115975), CD3 (GenBank GI #1345708 (epsilon subunit)), CD4 (GenBank GI #116013), CD5 (GenBank GI #116024), CD8 (GenBank GI #116035), CD11c (GenBank GI #386831), CD14 (GenBank GI #29741), CD15 (GenBank GI #4503811), CD19 (GenBank GI #178667), CD20 (GenBank GI #115968), CD21 (GenBank GI #117315), CD22 (GenBank GI #29779), CD23 (GenBank GI #119862), CD25 (GenBank GI #124317), CD30 (GenBank GI #115978), CD33 (GenBank GI #115979), CD37 (GenBank GI #115983), CD38 (GenBank GI #180119), CD40 (GenBank GI #116000), CD44 (GenBank GI #950417), CD44v6 (CD44 isoforms containing variant exon 6, e.g., GenBank GI #48255937, GenBank GI #48255935), CD45 (GenBank GI #34281), CD46 (GenBank GI #262938), CD48 (GenBank GI #114871), CD51 (integrin αv) (GenBank GI #124959), CD52 (GenBank GI #3182945), CD54 (GenBank GI # 124098), CD56 (GenBank GI #3334473), CD61 (integrin P3) (GenBank GI #124968), CD66e (CEA) (GenBank GI #115940), CD70 (GenBank GI #545773), CD71 (transferrin receptor) (GenBank GI #136378), CD72 (GenBank GI #116029), CD74 (GenBank GI #10835071), CD80 (GenBank GI #461606), CD87 (uPAR) (GenBank GI #465003), CD95 (Apo-1, Fas) (GenBank GI #119833), CD97 (GenBank GI #42560541), CD98 (4F2) (GenBank GI # 112803), CD105 (GenBank GI #182091), CD122 (GenBank GI #124321), CD126 (GenBank GI #124343), CD135 (Flt3) (GenBank GI #544320), CD144 (vascular endothelial cadherin) (GenBank GI #13432109), CD146 (MUC18) (GenBank GI #1171064), CD152 (CTLA4) (GenBank GI #27735177), CD154 (CD40L) (GenBank GI #38412), CD155 (GenBank GI # 1346922), CD178 (CD95L) (GenBank GI #1345957), CD221 (insulin-like growth factor receptor 1) (GenBank GI #124240), CD224 (gamma glutamyl transferase) (GenBank GI # 121148), CD227 (MUCI) (GenBank GI #547937), CD243 (MDR1) (GenBank GI #2506118), BAFF (GenBank GI #13124573), BAFF receptor (GenBank GI #21264093), BST2 (GenBank GI #1705508), endosialin (GenBank GI #9966885), HLA-DR beta (GenBank GI #188241), tenascin (GenBank GI #3915888), her2/neu (GenBank GI #119533), Mucl6 (GenBank GI # 34501467), G250 (GenBank GI #5915865), TweakR (GenBank GI #21263626), PSMA (GenBank GI #548615), TRAIL-R1 (DR4) (GenBank GI #21264525), TRAIL-R2 (DR5) (GenBank GI #17380321), TP-1 antigen (Bruland et al. (1988) Cancer Res. 48: 5302-5309), 8H9 glycoprotein (Modak et al. (2001) Cancer Res. 61: 4048-4054), EGP-1 (TACSTD-2) (GenBank GI #1346075), KGF-2 (FGF-10) (GenBank GI #6015141), A33 antigen (GenBank GI #2842765), MCSP (GenBank GI #20141463), lactadherin (GenBank GI #2506380), EphA2 (GenBank GI #125333), EphA4 (GenBank GI #1711371), EphB2 (GenBank GI #12644190), CCR4 (GenBank GI #1705894), E48 (GenBank GI #2501524), 5T4 fetal protein trophoblast (GenBank GI #435655), Muc5AC (GenBank GI #46397621), FAPA (GenBank GI # 20140021), LTBR (GenBank GI #549090), CFR-1 (GenBank GI #17376711), PGRN (GenBank GI #121617), VEGFR-2 (GenBank GI #9087218), MOv18 (GenBank GI #544337), Cripto (GenBank GI #117473), Wnt-1 (GenBank GI #139743), Wnt-2 (GenBank GI # 4507927), parathyroid hormone-related peptide (GenBank GI #131542), scatter factor (GenBank GI #123116), EGF receptor (GenBank GI #2811086), TAG72 (Muraro et al. (1988) Cancer Res. 48: 4588-4596), CanAg (Baeckstrom et al. (1991) J Biol Chem. 266: 21537-21547 and GenBank GI #547937), C30.6 (Mount et al. (1994) Cancer Res. 54: 6160-6166), GD2 ganglioside (Nagata et al. (1992) J Biol Chem. 267: 12082-12089), GD3 ganglioside (Zou et al. (2004) J Biol Chem. 279: 25390-25399), adenocarcinoma Lewis Y antigen (Nudelman et al. (1986) J Biol Chem. 261: 11247-11253; Kim et al. (1986) Cancer Res. 46: 5985-5992), Human carcinoma L6 carbohydrate (Hellstrom et al. (1986) Cancer Res. 46: 3917-3923; Fell et al. (1992) J Biol Chem. 267:15552-15558), IL-8 (GenBank GI #124359), EpCam (TACSTD-1, EGP-2) (GenBank GI #120749), LI-CAM splice variant (Meli et al. (1999) Int J Cancer. 83: 401-408; GenBank GI #4557707, 13435353), vitronectin (GenBank GI #139653), placental alkaline phosphatase (GenBank GI #130737), neuropilin (GenBank GI #9297107), and B-cell-tumor-associated antigens, including vascular endothelial antigens, such as vascular endothelial growth factor (VEGF) (GenBank GI #30172564) and placenta growth factor (PLGF) (GenBank GI #17380553). For brevity, the GenBank GI #s provided are intended as representative and may be considered a preferred sequence, however they are meant to encompass splice variants, variants, isoforms, polymorphisms, mutations, modifications, and the like, preferably those associated with cancer. Preferably such variant sequences have at least 90% sequence identity to the representative sequence, more preferably at least 95% sequence identity, or at least 96%, 97%, 98%, or 99% sequence identity. Proteins presented in their precursor form, are also preferred in their mature form. Proteins present in hetero- or homo-multimers may be targeted as individual proteins or as part of their multimeric complex (e.g., integrin αvβ3). Multimer subunits presented (e.g. CD3 epsilon subunit) may be taken as more preferable subunits, but the other subunits and multimeric forms are also preferred. In a related vein, additional specificities of the antibodies and the like can be the same or different.
Methods for producing tetrameric antibodies and domain-deleted antibodies, in particular CH2 domain-deleted antibodies, are disclosed in WO 02/060955 and WO 02/096948. Domain deleted antibodies are antibodies wherein a portion of one or more of the constant region domains has been deleted or otherwise altered so as to provide desired biochemical characteristics, e.g., increased tumor localized or reduced serum half-life. The modified antibodies may comprise alterations or modifications to one or more of the three heavy chain constant domains (CH1, CH2, or CH3) and/or to the light chain constant domain (CL). In a preferred embodiment the domain deleted antibody will have the entire CH2 domain removed and/or an amino acid spacer substituted for a deleted domain to provide flexibility and freedom of movement to the variable region.
As discussed above, because humanized and human antibodies are far less immunogenic in humans than other species monoclonal antibodies, e.g., murine antibodies, they can be used for the treatment of humans with far less risk of anaphylaxis. Thus, these antibodies may be preferred in therapeutic applications that involve in vivo administration to a human such as the use of such antibodies as radiation sensitizers for the treatment of neoplastic disease or in methods to reduce the side effects of additional therapies such as cancer therapy.
The invention provides functionally-active fragments, derivatives or analogues of the anti-TAT-001 polypeptide immunoglobulin molecules. “Functionally-active” in this context means that the fragment, derivative or analogue is able to induce anti-anti-idiotype antibodies (i.e. tertiary antibodies) that recognize the same antigen that is recognized by the antibody from which the fragment, derivative or analogue is derived. Specifically, in a preferred embodiment, the antigenicity of the idiotype of the immunoglobulin molecule may be enhanced by deletion of framework and CDR sequences that are C-terminal to the CDR sequence that specifically recognizes the antigen. To determine which CDR sequences bind the antigen, synthetic peptides containing the CDR sequences can be used in binding assays with the antigen by any binding assay method known in the art.
The present invention provides antibody fragments such as, but not limited to, F(ab′)2, F(ab)2, Fab′, Fab, scFvs. Antibody fragments which recognize specific epitopes may be generated by known techniques, e.g., by pepsin or papain-mediated cleavage. F(ab′)2 fragments consist of the variable region, the light chain constant region and the CH1 domain of the heavy chain and are generated by pepsin digestion of the antibody molecule. Fab fragments are generated by reducing the disulphide bridges of the F(ab′)2 fragments. The invention also provides heavy chain and light chain dimers of the antibodies of the invention, or any minimal fragment thereof such as Fvs or single chain antibodies (SCAs) (e.g., as described in U.S. Pat. No. 4,946,778; Bird (1988) Science 242: 423-42; Huston et al. (1988) Proc Natl Acad Sci. U.S.A. 85: 5879-5883; and Ward et al. (1989) Nature 334: 544-54), or any other molecule with the same specificity as the antibody of the invention. Single chain antibodies are formed by linking the heavy and light chain fragments of the Fv region via an amino acid bridge, resulting in a single chain polypeptide. Techniques for the assembly of functional Fv fragments in E. coli may be used (Skerra et al. (1988) Science 242: 1038-1041).
Alternatively, a clone encoding at least the Fab portion of the antibody may be obtained by screening Fab expression libraries (e.g., as described in Huse et al. (1989) Science 246: 1275-1281) for clones of Fab fragments that bind the specific antigen or by screening antibody libraries (see, e.g., Clackson et al. (1991) Nature 352: 624-628; Hanes and Pluckthun (1997) Proc Natl Acad Sci. U.S.A. 94: 4937-4942).
In other embodiments, the invention provides fusion proteins of the immunoglobulins of the invention, or fuictionally active fragments thereof. In one example, the immunoglobulin is fused via a covalent bond (e.g., a peptide bond), at either the N-terminus or the C-terminus to an amino acid sequence of another protein (or portion thereof, preferably at least 10, 20 or 50 amino acid portion of the protein) that is not the immunoglobulin. Preferably the immunoglobulin, or fragment thereof, is covalently linked to the other protein at the N-terminus of the constant domain. As stated above, such fusion proteins may facilitate purification, increase half-life in vivo, and enhance the delivery of an antigen across an epithelial barrier to the immune system.
Intrabodies—intracellular antibodies or fragments thereof—are also contemplated. See for example: Bonnin et al. (2004) Methods 34: 225-232; Auf der Maur et al. (2004) Methods 34: 215-224; Kontermann (2004) Methods 34: 163-170; Visintin et al. (2004) Methods 34: 200-214; Colby et al. (2004) J Mol Biol. 342: 901-912; Ewert et al. (2004) Methods 34: 184-199; Strube and Chen (2004) Methods 34: 179-183; Blazek and Celer (2003) Folia Microbiol (Praha). 48: 687-698; Tanaka et al. (2003) J Mol Biol. 331: 1109-1120; Donini et al. (2003) J Mol Biol. 330: 323-332; Tanaka et al. (2003) Nucleic Acids Res. 31: e23; Nam et al. (2002) Methods Mol Biol. 193: 301-327; Auf der Maur et al. (2002) J Biol Chem. 277: 45075-45085; Auf der Maur et al. (2001) FEBS Lett. 508: 407-412; Cohen (2002) Methods Mol Biol. 178: 367-378; Strube and Chen (2002) J Immunol Methods. 263: 149-167; Rajpal and Turi (2001) J Biol Chem. 276: 33139-33146; Ohage and Steipe (1999) J Mol Biol. 291: 1119-1128; Ohage et al. (1999) J Mol Biol. 291: 1129-1134; Wirtz and Steipe (1999) Protein Sci. 8: 2245-2250; Proba et al. (1998) J Mol Biol. 275: 245-253; Steipe (2004) Methods Enzymol. 388: 176-186.
In another embodiment, the invention provides for the compositions and use of pooled antibodies, antibody fragments, and the other antibody variants described herein. For example, two or more monoclonals may be pooled for use.
In the production of antibodies, screening for the desired antibody, fragment, or modification thereof can be accomplished by techniques known in the art, e.g., ELISA (enzyme-linked immunosorbent assay), or panels of hybridomas or purified monoclonal antibodies may be screened using antigen displayed on the surface of filamentous bacteriophage as described in Lijnen et al. (1997) Anal Biochem. 248: 211-215. For example, to select antibodies which recognize a specific domain of a TAT-001 polypeptide, one may assay generated hybridomas for a product which binds to a polypeptide fragment containing such domain. For selection of an antibody that specifically binds a first polypeptide homologue but which does not specifically bind to (or binds less avidly to) a second polypeptide homologue, one can select on the basis of positive binding to the first polypeptide homologue and a lack of binding to (or reduced binding to) the second polypeptide homologue. Antibodies can also be evaluated by flow cytometry on cells transfected with the target protein. Antibodies that contain appropriate reactivity can then be tested for their specificity in transfected cells and tissue sections, if applicable.
vi.) Antibody Nucleic Acids
The nucleic acid encoding an antibody may be obtained by cloning the antibody. If a clone containing the nucleic acid encoding the particular antibody is not available, but the sequence of the antibody molecule is known, a nucleic acid encoding the antibody may be obtained from a suitable source (e.g., an antibody cDNA library, or cDNA library generated from any tissue or cells expressing the antibody) by PCR amplification using synthetic primers hybridizable to the 3′ and 5′ ends of the sequence or by cloning using an oligonucleotide probe specific for the particular gene sequence.
The nucleic acid encoding the antibody may be used to introduce the nucleotide substitution(s) or deletion(s) necessary to substitute (or delete) one or more variable region cysteine residues participating in an intrachain disulphide bond with an amino acid residue that does not contain a sulphydryl group. Such modifications can be carried out by any method known in the art for the introduction of specific mutations or deletions in a nucleotide sequence, including, for example, but not limited to, chemical mutagenesis, in vitro site directed mutagenesis (Hutchinson et al. (1978) J Biol Chem. 253: 6551-6560) and PCR based methods. In addition, techniques developed for the production of “chimeric antibodies” (Morrison et aL (1984) Proc Natl Acad Sci. U.S.A. 81: 851-855; Neuberger et al. (1984) Nature 312: 604-608; Takeda et al. (1985) Nature 314: 452-454) by splicing genes from a mouse antibody molecule of appropriate antigen specificity together with genes from a human antibody molecule of appropriate biological activity can also be used. As described supra, a chimeric antibody is a molecule in which different portions are derived from different animal species, such as those having a variable region derived from a murine mAb and a human antibody constant region, e.g., humanized antibodies.
vii.) Antibody Production
The antibodies of the invention can be produced by any method known in the art for the synthesis of antibodies (e.g., chemical synthesis), and are preferably produced by a recombinant expression technique.
Recombinant expression of antibodies, or fragments, derivatives or analogues thereof, requires construction of a nucleic acid that encodes the antibody. If the nucleotide sequence of the antibody is known, a nucleic acid encoding the antibody may be assembled from chemically synthesized oligonucleotides (e.g., as described in Kutemeier et al. (1994) Biotechniques 17: 242-246), which, briefly, involves the synthesis of overlapping oligonucleotides containing portions of the sequence encoding antibody, annealing and ligation of those oligonucleotides, and then amplification of the ligated oligonucleotides by PCR.
Immunoglobulins (Ig) and certain variants thereof are known and many have been prepared in recombinant cell culture. For example, see U.S. Pat. Nos. 4,745,055 and 5,116,964; EP 256,654; EP 120,694; EP 125,023; EP 255,694; EP 266,663; WO 88/03559; Falkner and Zachau (1982) Nature, 298: 286-288; Morrison (1979) J Immun. 123: 793-800; Koehler et al. (1980) Proc Natl Acad Sci. U.S.A. 77: 2197-2199; Raso and Griffin (1981) Cancer Res. 41: 2073-2078; Morrison and Oi (1984) Ann Rev Immunol. 2: 239-256; Morrison (1985) Science 229: 1202-1207; and Morrison et al. (1984) Proc Natl Acad Sci. U.S.A. 81: 6851-6855. Reassorted immunoglobulin chains are also known. See, for example, U.S. Pat. No. 4,444,878; WO 88/03565; and EP 68,763 and references cited therein. The immunoglobulin moiety in the chimeras of the present invention may be obtained from IgG-1, IgG-2, IgG-3, or IgG-4 subtypes, IgA, IgE, IgD, or IgM, preferably from IgG-1 or IgG-3.
Once a nucleic acid encoding at least the variable domain of the antibody molecule is obtained, it may be introduced into a vector containing the nucleotide sequence encoding the constant region of the antibody molecule (see, e.g., WO 86/05807; WO 89/01036; and U.S. Pat. No. 5,122,464). Vectors containing the complete light or heavy chain for co-expression with the nucleic acid to allow the expression of a complete antibody molecule are also available.
The expression vector may be transferred to a host cell by conventional techniques and the transfected cells can then be cultured by conventional techniques to produce an antibody of the invention. The host cells used to express a recombinant antibody of the invention may be either bacterial cells such as Escherichia coli, or, preferably, eukaryotic cells, especially for the expression of whole recombinant antibody molecule. In particular, mammalian cells such as Chinese hamster ovary cells (CHO) in conjunction with a vector (e.g., a vector containing the major intermediate early gene promoter element from human cytomegalovirus) is an effective expression system for antibodies (Ramirez-Solis et al. (1990) Gene. 87: 291-4; Foecking and Hofstetter (1986) Gene. 45: 101-105; Cockett et al. (1990) Biotechnology. 8: 662-667).
A variety of host-expression vector systems, inclusive of those described herein for TAT-001 polypeptides, may be utilized to express an antibody molecule of the invention. Such host-expression systems represent vehicles by which the coding sequences of interest may be produced and subsequently purified, but also represent cells which may, when transformed or transfected with the appropriate nucleotide coding sequences, express the antibody molecule of the invention in situ. These include but are not limited to microorganisms such as bacteria (e.g., E. coli, B. subtilis) transformed with recombinant bacteriophage DNA, plasmid DNA or cosmid DNA expression vectors containing antibody coding sequences; yeast (e.g., Saccharomyces, Pichia) transformed with recombinant yeast expression vectors containing antibody coding sequences; insect cell systems infected with recombinant virus expression vectors (e.g., baculovirus) containing the antibody coding sequences; plant cell systems infected with recombinant virus expression vectors (e.g., cauliflower mosaic virus, CAMV; tobacco mosaic virus, TMV) or transformed with recombinant plasmid expression vectors (e.g., Ti plasmid) containing antibody coding sequences; or mammalian cell systems (e.g., COS, CHO, BHK, 293, 3T3 cells) harboring recombinant expression constructs containing promoters derived from the genome of mammalian cells (e.g., metallothionein promoter) or from mammalian viruses (e.g., the adenovirus late promoter; the vaccinia virus 7.5K promoter).
In bacterial systems, a number of expression vectors may be advantageously selected depending upon the use intended for the antibody molecule being expressed. For example, when a large quantity of such a protein is to be produced, for the generation of pharmaceutical compositions comprising an antibody molecule, vectors which direct the expression of high levels of fusion protein products that are readily purified may be desirable.
Such vectors include, but are not limited, to the E. coli expression vector pUR278 (Ruther and Muller-Hill (1983) EMBO J. 2: 1791-1794), in which the antibody coding sequence may be ligated individually into the vector in frame with the lac Z coding region so that a fusion protein is produced; pIN vectors (Inouye and Inouye (1985) Nucleic Acids Res. 13: 3101-3109; Van Heeke & Schuster (1989) J Biol Chem. 24: 5503-5509), and the like. pGEX vectors (see, for example,
The antibody coding sequence may be cloned individually into non-essential regions (e.g., the polyhedrin gene) of the virus and placed under control of an ACNPV promoter (e.g., the polyhedrin promoter). In mammalian host cells, a number of viral-based expression systems (e.g., an adenovirus expression system) may be utilized.
As discussed above, a host cell strain may be chosen which modulates the expression of the inserted sequences, or modifies and processes the gene product in the specific fashion desired. Such modifications (e.g., glycosylation) and processing (e.g., cleavage) of protein products may be important for the function of the protein.
For long-term, high-yield production of recombinant antibodies, stable expression is preferred. For example, cells lines that stably express an antibody of interest can be produced by transfecting the cells with an expression vector comprising the nucleotide sequence of the antibody and the nucleotide sequence of a selectable marker (e.g., neomycin or hygromycin), and selecting for expression of the selectable marker. Such engineered cell lines may be particularly useful in screening and evaluation of compounds that interact directly or indirectly with the antibody molecule.
The expression levels of the antibody molecule can be increased by vector amplification (for a review, see Bebbington and Hentschel (1987) “The use of vectors based on gene amplification for the expression of cloned genes in mammalian cells” in DNA cloning, Vol. 3, Academic Press, New York). When a marker in the vector system expressing antibody is amplifiable, an increase in the level of inhibitor present in culture of host cell will increase the number of copies of the marker gene. Since the amplified region is associated with the antibody gene, production of the antibody will also increase (Crouse et al. (1983) Mol Cell Biol. 3: 257-266).
The host cell may be co-transfected with two expression vectors for use within the invention, the first vector encoding a heavy chain derived polypeptide and the second vector encoding a light chain derived polypeptide. The two vectors may contain identical selectable markers which enable equal expression of heavy and light chain polypeptides. Alternatively, a single vector may be used which encodes both heavy and light chain polypeptides. In such situations, the light chain sequence should be placed upstream of the heavy chain sequence to avoid an excess of toxic free heavy chain (see Proudfoot (1986) Nature 322: 562-565; Kohler (1980) Proc Natl Acad Sci. U.S.A. 77: 2197-2199). The coding sequences for the heavy and light chains may comprise cDNA or genomic DNA.
Once the antibody molecule of the invention has been recombinantly expressed, it may be purified by any method known in the art for purification of an antibody molecule, for example, by chromatography (e.g., ion exchange chromatography, affinity chromatography such as with protein A or specific antigen, and sizing column chromatography), centrifugation, differential solubility, or by any other standard technique for the purification of proteins.
Alternatively, any fusion protein may be readily purified by utilizing an antibody specific for the fusion protein being expressed. For example, a system described by Janknecht et al. ((1991) Proc Natl Acad Sci. U.S.A. 88: 8972-8976) allows for the ready purification of non-denatured fusion proteins expressed in human cell lines. In this system, the gene of interest is subcloned into a vaccinia recombination plasmid such that the open reading frame of the gene is translationally fused to an amino-terminal tag consisting of six histidine residues. The tag serves as a matrix binding domain for the fusion protein. Extracts from cells infected with recombinant vaccinia virus are loaded onto Ni2+ nitriloacetic acid-agarose columns and histidine-tagged proteins are selectively eluted with imidazole-containing buffers.
The immunoglobulins of the invention include analogues and derivatives that are either modified, i.e. by the covalent attachment of any type of molecule as long as such covalent attachment that does not impair immunospecific binding beyond the preferred binding affinity range discussed above. For example, the derivatives and analogues of the immunoglobulins include those that have been further modified, e.g., by glycosylation, acetylation, pegylation, phosphylation, amidation, derivatisation by protecting/blocking groups, proteolytic cleavage, and linkage to a cellular ligand or other protein, etc. Any of numerous chemical modifications may be carried out by known techniques, for example specific chemical cleavage, acetylation, formylation, etc. Additionally, the analogue or derivative may contain one or more non-classical amino acids.
Antibodies of the invention and fragments thereof, e.g., domain-deleted antibody fragments, will be useful for purifying TAT-001 antigens, and for passive anti-cancer immunotherapy, or may be attached to therapeutic effector moieties, e.g., radiolabels, cytotoxins, therapeutic enzymes, agents that induce apoptosis, in order to provide for targeted cytotoxicity, i.e., killing of human colon tumor cells.
Anti-TAT-001 antibodies or fragments thereof may be administered in labeled or unlabeled form, alone or in combination with other therapeutics, e.g., chemotherapeutics such as cisplatin, methotrexate, adriamycin, and other chemotherapies suitable for colon cancer therapy, therapeutic proteins such as lymphokines and cytokines, diagnostic and therapeutic enzymes, radionuclides, prodrugs, cytotoxins, and the like. Antibodies of the invention or fragments thereof can thus be conjugated to a therapeutic agent or drug moiety to modify a given biological response. The therapeutic agent or drug moiety can include classical chemical therapeutic agents (e.g., adriamycin, methotrexate, cisplatin, daunorubicin, doxorubicin, methopterin, caminomycin, mitheramycin, streptnigrin, chlorambucil, and ifosfimide). For example, the drug moiety may be a protein or polypeptide possessing a desired biological activity. Such proteins may include toxins, e.g., abrin, ricin A, calicheamicin, euperamicin, dynemicin, pseudomonas exotoxin, cholera toxin, diphtheria toxin and variants thereof; therapeutic proteins, e.g., tumor necrosis factor, α-interferon, γ-interferon, nerve growth factor, platelet derived growth factor, and tissue plasminogen activator; thrombotic agents; anti-angiogenic agents, e.g., angiostatin or endostatin; biological response modifiers, e.g., lymphokines, interleukin-1 (IL-1), interleukin-2 (IL-2), interleukin-6 (IL-6), granulocyte macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-CSF), nerve growth factor (NGF), and other growth factors; hormones and hormone antagonists, e.g., corticosteroids (e.g., prednisone), progestins, antiestrogens (e.g., tamoxifm), androgens (e.g., testosterone), and aromatase inhibitors. Other therapeutic moieties may include radionuclides such as 90Y, 125I, 131I, 111In, 105Rh, 153Sm, 67Cu, 67Ga, 166Ho, 177Lo, 186Re, 213Bi, 211At, 109Pd, 212Bi, and 188Re; antibiotics, e.g., calicheamicin; pro-drugs such as phosphate-containing prodrugs, thiophosphate-containing prodrugs, sulfate containing prodrugs peptide containing prodrugs, and beta lactam containing prodrugs; and drugs such as but not limited to, alkylphosphocholines, topoisomerase I inhibitors, taxoids and suramin.
Techniques for conjugating such therapeutic moieties to antibodies are well known; see, e.g., Amon et al. (1985) “Monoclonal Antibodies for Immunotargeting of Drugs in Cancer Therapy” in Monoclonal Antibodies and Cancer Therapy, Reisfeld et al. (Eds.), pp. 243-256, Alan R. Liss, Inc.; Hellstrom et al. (1987) “Antibodies for Drug Delivery” in Controlled Drug Delivery, 2nd Edit. Robinson et al. (Eds.) pp. 623-653, Marcel Dekker, Inc.; Thorpe (1985) “Antibody Carriers of Cytotoxic Agents in Cancer Therapy: A Review” in Monoclonal Antibodies: Biological and Clinical Applications Pinchera et al. (Eds.) pp. 475-506; (1985) “Analysis, Results, and Future Prospective of the Therapeutic Use of Radiolabelled Antibody in Cancer Therapy” in Monoclonal Antibodies For Cancer Detection And Therapy, Baldwin et al. (Eds.) pp. 303-316, Academic Press; Thorpe et al. (1982) Immunol Rev. 62: 119-158; and Dubowchik et al. (1999) Pharmacol Ther. 83: 67-123. In another embodiment, an antibody may be conjugated to a second antibody to form an antibody heteroconjugate as described in U.S. Pat. No. 4,676,980. An antibody, with or without a therapeutic moiety conjugated to it, can be used as a therapeutic agent that is administered alone or in combination with cytotoxic factor(s) and/or cytokine(s).
The administered composition may include a pharmaceutically acceptable carrier, and optionally adjuvants and/or stabilizers used in antibody compositions for therapeutic use. Administration may be local or systemic. As noted, in a preferred embodiment radiolabeled antibodies will be prepared against one or more TAT-001 antigens and used for the treatment of colon cancer via radioimmunotherapy. Preferably these antibodies will not induce an immunogenic response as effective therapy will typically include chronic dosage in multiple administrations of the particular antibody, either in whole or conjugated form.
Screening Methods The invention provides methods for identifying candidate compounds that bind to a TAT-001 polypeptide or have a stimulatory or inhibitory effect on the expression or activity of a TAT-001 polypeptide. Examples of compounds, include, but are not limited to, nucleic acids (e.g., DNA and RNA), carbohydrates, lipids, proteins, peptides, peptidomimetics, hormones, cytokines, antibodies, agonists, antagonists, small molecules, aptamers (see U.S. Pat. Nos. 5,756,291 and 5,792,613), nucleic acid-protein fusions (see U.S. Pat. No. 6,489,116), other drugs, and combinations and variations thereupon. These methods, whether cell-based or cell-free, can be used to screen a plurality (e.g., a library) of candidate compounds.
Compounds can be obtained using any of the numerous suitable approaches in combinatorial library methods known in the art, including: biological libraries; spatially addressable parallel solid phase or solution phase libraries; synthetic library methods requiring deconvolution; the “one-bead one-compound” library method; and synthetic library methods using affinity chromatography selection. The biological library approach is limited to peptide libraries, while the other four approaches are applicable to peptide, non-peptide oligomer or small molecule libraries of compounds (Lam (1997) Anticancer Drug Des. 12: 145 -167; U.S. Pat. Nos. 5,738,996; and 5,807,683).
Examples of methods for the synthesis of molecular libraries may be found in the art, for example in: DeWitt et al. (1993) Proc Natl Acad Sci. U.S.A. 90: 6909-6913; Erb et al. (1994) Proc Natl Acad Sci. U.S.A. 91: 11422-11426; Zuckermann et al. (1994) J Med Chem. 37: 2678-2685; Cho et al. (1993) Science 261: 1303-1305; Carell et al. (1994) Angew Chem Int Ed Engl. 33: 2059-2061; Carell et al. (1994) Angew Chem Int Ed Engl. 33: 2061-2064; and Gallop etal. (1994) J Med Chem. 37: 1233-1251.
Libraries of compounds may be presented, e.g., presented in solution (e.g., Houghten (1992) Biotechniques. 13: 412-421), or on beads (Lam (1991) Nature 354: 82-84), chips (Fodor (1993) Nature 364: 555-556), bacteria (U.S. Pat. No. 5,223,409), spores (U.S. Pat. Nos. 5,571,698; 5,403,484; and 5,223,409), plasmids (Cull et al. (1992) Proc Natl Acad Sci. U.S.A. 89: 1865-1869) orphage (Scott and Smith (1990) Science 249: 386-390; Devlin (1990) Science 249: 404-406; Cwirla et al. (1990) Proc Natl Acad Sci. U.S.A. 87: 6378-6382; and Felici (1991) J Mol Biol. 222: 301-310).
In a preferred embodiment, the invention provides methods for the identification of compounds that inhibit TAT-001 polypeptide and/or polynucleotide expression or activity, that includes contacting a candidate compound with a TAT-001 and detecting the presence or absence of binding between said compound and said TAT-001, or detecting an alteration in TAT-001 expression or activity. Further methods are also included for the identification of compounds that inhibit TAT-001 expression or activity, comprising: administering a compound to a cell or cell population, and detecting an alteration in TAT-001 expression or activity. Preferably such compounds inhibit at least 0.1%, at least 1%, at least 5%, or at least 10% of the activity of a TAT-001 polypeptide or TAT-001 nucleic acid sequence described herein. More preferably, such compounds inhibit at least 25%, at least 50%, at least 75%, or at least 90% of the activity of a TAT-001 polypeptide or TAT-001 nucleic acid sequence described herein. Most preferably, such compounds inhibit at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% of the activity of a TAT-001 polypeptide or TAT-001 nucleic acid sequence described herein.
In another embodiment, compounds that modulate (e.g., upregulate or downregulate) the expression of a TAT-001 polypeptide and/or polynucleotide are identified in a cell-based assay. Accordingly, a population of cells expressing a TAT-001 polypeptide or nucleic acid are contacted with a candidate compound and the ability of the candidate compound to alter expression of the TAT-001 polypeptide or TAT-001 nucleic acid is determined by comparison to a reference range or control. In another embodiment, a first and second population of cells expressing a TAT-001 polypeptide or TAT-001 nucleic acid are contacted with a candidate compound or a control and the ability of the candidate compound to alter the expression of the TAT-001 polypeptide or TAT-001 nucleic acid is determined by comparing the difference in the level of expression of the TAT-001 polypeptide or TAT-001 nucleic acid between the first and second populations of cells. In a further embodiment, the expression of the TAT-001 polypeptide or TAT-001 nucleic acid in the first population may be further compared to a reference range or control. Preferably such compounds modulate by at least 0.1%, at least 1%, at least 5%, or at least 10% the expression of a TAT-001 polypeptide or TAT-001 nucleic acid sequence described herein. More preferably, such compounds modulate by at least 25%, at least 50%, at least 75%, or at least 90% of expression of a TAT-001 polypeptide or TAT-001 nucleic acid sequence described herein. Most preferably, such compounds modulate by at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% the expression of a TAT-001 polypeptide or TAT-001 nucleic acid sequence described herein.
The candidate compound can then be identified as a modulator of the expression of the TAT-001 polypeptide or nucleic acid based on this comparison. For example, when expression of the TAT-001 polypeptide or mRNA encoding said polypeptide is significantly greater in the presence of the candidate compound than in its absence, the candidate compound is identified as a stimulator of expression of the TAT-001 polypeptide or MRNA encoding said polypeptide.
Alternatively, when expression of the TAT-001 polypeptide or MRNA encoding the polypeptide is significantly less in the presence of the candidate compound than in its absence, the candidate compound is identified as an inhibitor of the expression of the TAT-001 polypeptide or mRNA encoding the polypeptide. The level of expression of a TAT-001 polypeptide, or the MRNA that encodes it, can be determined by methods known to those of skill in the art based on the present description. For example, TAT-001 MRNA expression can be assessed by Northern blot analysis or RT-PCR, and protein levels can be assessed by Western blot analysis or other means known in the art.
In another embodiment, compounds that modulate an activity or characteristic of a TAT-001 polypeptide are identified by contacting a preparation containing the TAT-001 polypeptide, or cells (e.g., prokaryotic or eukaryotic cells) expressing the TAT-001 polypeptide with a candidate compound or a control and determining the ability of the candidate compound to modulate (e.g., stimulate or inhibit) an activity of the TAT-001 polypeptide. An activity of a TAT-001 polypeptide can be assessed by detecting its effect on a “downstream effector” for example, induction of a cellular signal transduction pathway of the polypeptide (e.g., intracellular Ca2+, diacylglycerol, IP3, cAMP, or other intermediate), detecting catalytic or enzymatic activity of the TAT-001 polypeptide on a suitable substrate, detecting the induction of a reporter gene (e.g., a regulatory element that is responsive to a TAT-001 polypeptide and is operably linked to a nucleic acid encoding a detectable marker, e.g., luciferase), or detecting a cellular response, for example, cellular differentiation, or cell proliferation as the case may be, based on the present description, techniques known to those of skill in the art can be used for measuring these activities (see, e.g., U.S. Pat. No. 5,401,639).
The candidate compound can then be identified as a modulator of an activity of a TAT-001 polypeptide by comparing the effects of the candidate compound to the control. Suitable control compound include PBS and normal saline (NS). Preferably such compounds modulate an activity of a TAT-001 polypeptide sequence described herein by at least 0.1%, at least 1%, at least 5%, or at least 10%. More preferably, such compounds modulate an activity of a TAT-001 polypeptide sequence described herein by at least 25%, at least 50%, at least 75%, or at least 90%. Most preferably, such compounds modulate an activity of a TAT-001 polypeptide sequence described herein by at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%.
In another embodiment, a cell-based assay system is used to identify compounds that bind to or modulate an activity of a protein, such as an enzyme, or a biologically active portion thereof, which is responsible for the production or degradation of the TAT-001 polypeptide or is responsible for the post-translational modification of the TAT-001 polypeptide. In a primary screen, a plurality (e.g., a library) of agents are contacted with cells that naturally or recombinantly express: (i) a TAT-001 polypeptide and (ii) a protein that is responsible for processing of the TAT-001 polypeptide in order to identify compounds that modulate the production, degradation, or post-translational modification of the TAT-001 polypeptide. If desired, compounds identified in the primary screen can then be assayed in a secondary screen against cells naturally or recombinantly expressing the TAT-001 polypeptide. The ability of the candidate compound to modulate the production, degradation or post-translational modification of a TAT-001 polypeptide can be determined by methods known to those of skill in the art, for example, a kinase assay, a phosphatase assay, flow cytometry, a scintillation assay, immunoprecipitation and Western blot analysis. Preferably such compounds modulate the activity of such regulatory proteins as it pertains to TAT-001 polypeptide sequence described herein by at least 0.1%, at least 1%, at least 5%, or at least 10%. More preferably, such compounds modulate the activity by at least 25%, at least 50%, at least 75%, or at least 90%. Most preferably, such compounds modulate the activity by at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%.
In yet another embodiment, cells expressing a TAT-001 polypeptide are contacted with a plurality of candidate compounds. The ability of such a compound to modulate the production, degradation or post-translational modification of a TAT-001 polypeptide can be determined by methods known to those of skill in the art, as described above.
In another embodiment, compounds that modulate (i.e., upregulate or downregulate) the expression, an activity or both the expression and activity of a TAT-001 polypeptide are identified in an animal model (e.g., mice, rats, rabbits, monkeys, guinea pigs, dogs and cats), preferably representing a model of cancer. Accordingly, a first and second group of animals are administered a candidate compound or a control, and the ability of the candidate compound to modulate the expression of the TAT-001 polypeptide or nucleic acid is determined by comparing the difference in the level of expression between the first and second group of animals. Where desired, the expression levels of the TAT-001 polypeptide or nucleic acid in the first and second groups of animals can be compared to the level of a TAT-001 polypeptide or nucleic acid in a control group of animals. The candidate agent or a control agent can be administered by means known in the art (e.g., orally, rectally or parenterally such as intraperitoneally or intravenously). Changes in the expression of a TAT-001 polypeptide or nucleic acid can be assessed as outlined above.
Methods are also provided for selecting TAT-001 binding molecules, such as antibodies, antibody-related proteins, or small molecules are provided. Such methods include a method for selecting an antibody that binds with high binding affinity to a mammalian TAT-001 that includes the steps of: (a) providing a peptide comprising a TAT-001 polypeptide, optionally coupled to an immunogenic carrier and (b) contacting the TAT-001 polypeptide with a TAT-001 binding molecule, wherein the TAT-001 binding molecule is an antibody, under conditions that allow for complex formation between the TAT-001 polypeptide and the antibody, thereby selecting a TAT-001 binding molecule that binds with high binding affinity to a mammalian TAT-001. Preferably such compounds bind one or more TAT-001 polypeptides specifically. Such compounds may also include, but are not limited to, nucleic acids (e.g., DNA and RNA), carbohydrates, lipids, proteins, peptides, peptidomimetics, hormones, cytokines, antibodies, agonists, antagonists, small molecules, aptamers (see U.S. Pat. Nos. 5,756,291 and 5,792,613), nucleic acid-protein fusions (see U.S. Pat. No.6,489,116), other drugs, and combinations and variations thereupon. Such compounds may have uses in diagnosis of cancer, such as colon cancer. Such compounds may also have uses in treatment of cancer, such as colon cancer, even in the absence of a measurable alteration in TAT-001 expression or activity, for example, such as might be expected in a non-activity based binding assay.
In one embodiment, compounds that bind to a TAT-001 polypeptide are identified in a cell-based assay system. Cells expressing a TAT-001 polypeptide are contacted with a candidate compound and the ability of the candidate compound to interact with the TAT-001 polypeptide is determined. Preferably, the ability of a candidate compound to interact with a TAT-001 polypeptide is compared to a reference range or control. In another embodiment, two populations of cells expressing a TAT-001 polypeptide are contacted with a candidate compound or a control and the ability of the candidate compound to interact with the polypeptide is determined by comparing the difference in interaction between the candidate compound and control. If desired, this assay may be used to screen a plurality (e.g., a library) of candidate compounds. The cell, for example, can be of prokaryotic origin (e.g., E. coli) or eukaryotic origin (e.g., yeast or mammalian). Further, the cells can express the TAT-001 polypeptide endogenously or be genetically engineered to express the polypeptide. In some embodiments, the TAT-001 polypeptide or the candidate compound is labelled, for example with a radioactive label (such as 32P, 35S or 125I) or a fluorescent label (such as fluorescein isothiocyanate, rhodamine, phycoerythrin, phycocyanin, allophycocyanin, o-phthaldehyde or fluorescamine) to enable detection of an interaction between a polypeptide and a candidate compound. The ability of the candidate compound to interact directly or indirectly with the TAT-001 polypeptide can be determined by methods known to those of skill in the art (e.g., by flow cytometry, a scintillation assay, immunoprecipitation or Western blot analysis).
In another embodiment, compounds that bind to a TAT-001 polypeptide are identified in a cell-free assay system where a native or recombinant TAT-001 polypeptide is contacted with a candidate compound and the ability of the candidate compound to interact with the polypeptide is determined. Preferably, the ability of a candidate compound to interact with a TAT-001 polypeptide is compared to a reference range or control. Alternatively, a first and second sample comprising native or recombinant TAT-001 polypeptide are contacted with a candidate compound or a control and the ability of the candidate compound to interact with the polypeptide is determined by comparing the difference in interaction between the candidate compound and control. If desired, this assay may be used to screen a plurality (e.g., a library) of candidate compounds. Preferably, the TAT-001 polypeptide is first immobilized, by, for example, contacting the TAT-001 polypeptide with an immobilized antibody which specifically recognizes and binds it, or by contacting a purified preparation of polypeptide with a surface designed to bind proteins. The TAT-001 polypeptide may be partially or completely purified (e.g., partially or completely free of other polypeptides) or part of a cell lysate. Further, the TAT-001 polypeptide may be a fusion protein comprising the TAT-001 polypeptide or a biologically active portion thereof and a domain such as glutathionine-S-transferase.
Alternatively, the TAT-001 polypeptide can be biotinylated using techniques well known to those of skill in the art (e.g., biotinylation kit, Pierce Chemicals; Rockford, Ill.). The ability of a candidate agent to interact with a TAT-001 polypeptide can be duplicated by methods known to those of skill in the art.
In one embodiment, a TAT-001 polypeptide is used as a “bait protein” in a two-hybrid assay or three-hybrid assay to identify other proteins that bind to or interact with the TAT-001 polypeptide (see e.g., U.S. Pat. No. 5,283,317; Zervos et al. (1993) Cell 72: 223-232; Madura et al. (1993) J Biol Chem. 268: 12046-12054; Bartel et al. (1993) Biotechniques. 14: 920-924; Iwabuchi et al. (1993) Oncogene. 8: 1693-1696; and WO 94/10300). As those skilled in the art will appreciate, such binding proteins are also likely to be involved in the propagation of signals by a TAT-001 polypeptide. For example, they may be upstream or downstream elements of a signaling pathway involving a TAT-001 polypeptide. Alternatively, polypeptides that interact with a TAT-001 polypeptide can be identified by isolating a protein complex comprising a TAT-001 polypeptide (i.e. a TAT-001 polypeptide which interacts directly or indirectly with one or more other polypeptides) and identifying the associated proteins using methods known in the art such as mass spectrometry or Western blotting (for examples see Blackstock and Weir (1999) Trends in Biotechnology 17: 121-127; Rigaut (1999) Nat Biotechnol. 17:1030-1032; Husi (2000) Nat Neurosci. 3: 661-669; Ho et al. (2002) Nature 415: 180-183; Gavin et al. (2002) Nature 415: 141-147).
In all cases, the ability of the candidate compound to interact directly or indirectly with the TAT-001 polypeptide can be determined by methods known to those of skill in the art. For example but without limitation, the interaction between a candidate compound and a TAT-001 polypeptide can be determined by flow cytometry, a scintillation assay, an activity assay, mass spectrometry, microscopy, immunoprecipitation or Western blot analysis. Panels of hybridomas or purified monoclonal antibodies may be screened, for example, using antigen displayed on the surface of filamentous bacteriophage as described in Lijnen et al. (1997) Anal Biochem. 248: 211-215.
Also provided are comparative methods for identifying a candidate compound for the treatment of cancer, that include: (a) measuring the binding of a TAT-001 binding molecule to a TAT-001 polypeptide in the presence of a test compound; and (b) measuring the binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound; wherein a level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the presence of the test compound that is less than the level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound is an indication that the test compound is a potential therapeutic compound for the treatment of a cancer. Also provided are methods for identifying a compound for diagnosing a cancer that include: (a) measuring the binding of a TAT-001 binding molecule to a TAT-001 polypeptide in the presence of a test compound; and (b) measuring the binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound; wherein a level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the presence of the test compound that is less than the level of binding of the TAT-001 binding molecule to a TAT-001 polypeptide in the absence of the test compound is an indication that the test compound is a potential compound for diagnosing a cancer.
In another embodiment, the availability of isolated TAT-001 polypeptides also allows for the identification of small molecules and low molecular weight compounds that inhibit the binding of TAT-001 polypeptides to binding partners (such as antibodies, CDR regions, substrates, or interacting cellular biomolecules) through routine application of high-throughput screening methods (HTS). HTS methods generally refer to technologies that permit the rapid assaying of lead compounds for therapeutic potential. HTS techniques may employ robotic handling of test materials, detection of positive signals, and interpretation of data. Lead compounds may be identified via the incorporation of radioactivity or through optical assays that rely on absorbance, fluorescence or luminescence as read-outs (Gonzalez et al. (1998) Curr Opin Biotech. 9: 624-631).
Model systems are available that can be adapted for use in high throughput screening for compounds that inhibit the interaction of protein with its ligand, for example, by competing with protein for ligand binding. Sarubbi et al. ((1996) Anal Biochem. 237: 70-75) describes cell-free, non-isotopic assays for discovering molecules that compete with natural ligands for binding to the active site of IL-1 receptor. Martens et al. (1999) Anal Biochem. 273: 20-31 describes a generic particle-based non-radioactive method in which a labeled ligand binds to its receptor immobilized on a particle; label on the particle decreases in the presence of a molecule that competes with the labeled ligand for receptor binding.
One skilled in the art will also appreciate that a TAT-001 polypeptide may also be used in a method for the structure-based design of an anti-cancer agent, in particular a small molecule which acts to modulate (e.g., stimulate or inhibit) the activity of the polypeptide. Such a method can include the following steps: 1) determining the three-dimensional structure of the polypeptide; 2) deducing the three-dimensional structure within the polypeptide of the likely reactive or binding site(s) of the agent; 3) synthesizing candidate agents that are predicted to react or bind to the deduced reactive or binding site; and 4) testing whether the candidate agent is able to modulate the activity of the polypeptide. It will be appreciated that the method described above is likely to be an iterative process.
In another embodiment, compounds that competitively interact with (i.e., bind to) a TAT-001 polypeptide are identified in a competitive binding assay. In accordance with this embodiment, cells expressing the polypeptide are contacted with a candidate compound and a compound known to interact with the polypeptide (e.g., an antibody or CDR region thereof); the ability of the candidate compound to competitively interact with the polypeptide is then determined. Alternatively, compounds that competitively interact with (i.e., bind to) a TAT-001 polypeptide are identified in a cell-free assay system by contacting the polypeptide with a candidate compound and a compound known to interact with the polypeptide. As stated above, the ability of the candidate compound to interact with a TAT-001 polypeptide can be determined by methods known to those of skill in the art.
In a preferred embodiment for therapeutic applications, identified compounds (preferably antibodies) that bind TAT-001 and/or modulate TAT-001 expression or activity also inhibit cell and/or tumor growth, proliferation, and/or metastasis, for example, such as might be present in a cellular proliferative disease; or contribute to cell death, such as through apoptosis. Such compounds can be said to be substances that modulate the status of a cell. For example, an anti-TAT-001 antibody may inhibit cell proliferation or promote cell death in colon tumor xenografts in mice via an immune response. Such properties may be assayed by methods known in the art, for example, cell death can be measured by determining cellular ATP levels, wherein a cell that is undergoing cell death has a decreased level of cellular ATP compared to a control cell. Cell death may also be measured by staining with a vital dye, for example, trypan blue, wherein a cell that is dying will be stained with the vital dye, and a cell that is not dying will not be stained with the dye. Inhibition of cell proliferation can be measured, for example, by determining by standard means the number of cells in a population contacted with the compound compared to the number of cells in a population not contacted with the compound. If the number of cells in the population contacted with the compound does not increase over time or increases at a reduced rate compared to cells not contacted with the compound, the candidate compound inhibits the proliferation of the cells. Common proliferation assays include incorporating a radiolabelled substance such as 3H-thymidine in the DNA, and the assay for incorporating bromodeoxyuridine developed by the Boehringer Mannheim GmbH. Cell growth can be measured, for example, by determining the relative size of individual cells or the relative mass of a population of cells between cells or populations of cells treated with the compound and untreated cells. Metastasis may be measured by, for example, by the methods described in U.S. Pat. Nos. 6,245,898 or 6,767,700, using appropriate tumor samples. Assays may be performed in cell culture, animal models, or in human clinical trials.
Compounds or agents identified as modulators of TAT-001 polypeptide or TAT-001 nucleic acid expression and/or activity, and/or identified as TAT-001 binding compounds by any of the methods herein may be used in further testing, or in therapeutic or prophylactic use as an anti-cancer agent. Thus, the present invention also provides assays for use in drug discovery or target validation in order to identify or verify the modulators of TAT-001, preferably for treatment or prevention of cancer. Test compounds can be assayed for their ability to modulate levels of a TAT-001 polypeptide in a subject having cancer. Compounds able to modulate levels of a TAT-001 polypeptide in a subject having cancer towards levels found in subjects free from cancer or to produce similar changes in experimental animal models of cancer can be used as lead compounds for further drug discovery, or used therapeutically. Such assays can also be used to screen candidate drugs, in clinical monitoring or in drug development, where an abundance of a TAT-001 polypeptide can serve as a surrogate marker for clinical disease.
Diagnostics
The invention provides methods for detecting the presence and status of TAT-001 polypeptides in various biological samples, as well as methods for identifying cells that express TAT-001 polypeptides. A typical embodiment of this invention provides methods for monitoring TAT-001 protein in a tissue or hematology sample having or suspected of having some form of growth dysregulation such as cancer.
In general, a cancer may be detected in a patient based on the presence of one or more colon cancer proteins and/or polynucleotides encoding such proteins in a biological sample (for example, blood, sera, sputum, urine and/or tumor biopsies) obtained from the patient. In other words, such proteins may be used as markers to indicate the presence or absence of a cancer such as colon cancer. In addition, such proteins may be useful for the detection of other cancers. The binding agents provided herein may generally permit detection of the level of TAT-001 antigen that binds to the agent in the biological sample. Binding agents may be compared or screened for based on their strength of binding, selectivity, and/or other properties to find preferrable binding agents for assays.
There are a variety of assay formats known to those of ordinary skill in the art for using a binding agent to detect polypeptide markers in a sample, for example, immunoprecipitation followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, 2-dimensional gel electrophoresis, competitive and non-competitive assay systems using techniques such as Western blots, immunocytochemistry, immunohistochemistry, immunoassays, e.g., radioimmunoassays, ELISA (enzyme linked immunosorbent assay), “sandwich” immunoassays, immunoprecipitation assays, precipitation reactions, gel diffusion precipitation reactions, immunodiffusion assays, agglutination assays, complement-fixation assays, immunoradiometric assays, fluorescent immunoassays and protein A immunoassays (See also, e.g., Harlow and Lane (1988) Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory). In general, the presence or absence of a cancer in a patient may be determined by (a) contacting a biological sample obtained from a patient with a binding agent; (b) detecting in the sample a level of TAT-001 polypeptide that binds to the binding agent; and (c) comparing the level of TAT-001 polypeptide with a cut-off value, preferably a predetermined cut-off value. Cut-off values may be determined by methods known in the art, such as by establishing ranges of expression that give degrees of confidence in distinguishing a tumor sample from a normal sample.
In a preferred embodiment, the assay involves the use of a binding agent immobilized on a solid support to bind to the TAT-001 polypeptide(s) in a sample. The bound polypeptide may then be detected using a detection reagent that contains a reporter group and specifically binds to the binding agent/TAT-001 polypeptide complex. Such detection reagents may comprise, for example, a binding agent that specifically binds to the TAT-001 polypeptide or an antibody or other agent that specifically binds to the binding agent, such as an anti-immunoglobulin, protein G, protein A, or a lectin. Alternatively, a competitive assay may be utilized, in which a TAT-001 polypeptide is labeled with a reporter group and allowed to bind to the immobilized binding agent after incubation of the binding agent with the sample. The extent to which components of the sample inhibit the binding of the labeled TAT-001 polypeptide to the binding agent is indicative of the reactivity of the sample with the immobilized binding agent. Suitable polypeptides for use within such assays include full length TAT-001 proteins and polypeptide portions thereof to which the binding agent binds, as described above.
The solid support may be any material known to those of ordinary skill in the art to which a TAT-001 polypeptide may be attached. For example, the solid support may be a test well in a microtiter plate or a nitrocellulose or other suitable membrane. Alternatively, the support may be a bead or disc, such as glass, fiberglass, latex or a plastic material such as polystyrene or polyvinylchloride. The support may also be a magnetic particle or a fiber optic sensor, such as those disclosed, for example, in U.S. Pat. No. 5,359,681. The binding agent may be immobilized on the solid support using a variety of techniques known to those of skill in the art, which are amply described in the patent and scientific literature. In the context of the present invention, the term “immobilization” refers to both noncovalent association, such as adsorption, and covalent attachment (which may be a direct linkage between the agent and functional groups on the support or may be a linkage by way of a cross-linking agent). Immobilization by adsorption to a well in a microtiter plate or to a membrane is preferred. In such cases, adsorption may be achieved by contacting the binding agent, in a suitable buffer, with the solid support for a suitable amount of time. The contact time varies with temperature, but is typically between about 1 hour and about 1 day. In general, contacting a well of a plastic microtiter plate (such as polystyrene or polyvinylchloride) with an amount of binding agent ranging from about 10 ng to about 10 μg, and preferably about 100 ng to about 1 μg, is sufficient to immobilize an adequate amount of binding agent.
Covalent attachment of binding agent to a solid support may generally be achieved by first reacting the support with a bifunctional reagent that will react with both the support and a functional group, such as a hydroxyl or amino group, on the binding agent. For example, the binding agent may be covalently attached to supports having an appropriate polymer coating using benzoquinone or by condensation of an aldehyde group on the support with an amine and an active hydrogen on the binding partner (see, e.g., Pierce Immunotechnology Catalog and Handbook (1991) at A12-A13).
In one embodiment, an antibody is used in the methods of screening and diagnosis to detect and quantify a TAT-001 polypeptide. Preferably, the antibody is used for detecting and/or quantifying the amount of a polypeptide as defmed in the first aspect of the invention in a biological sample obtained from said subject.
In one example, binding of antibody in tissue sections can be used to detect aberrant TAT-001 polypeptide localization or an aberrant level of a TAT-001 polypeptide. In a specific embodiment, an antibody recognizing a TAT-001 polypeptide can be used to assay a patient tissue (e.g., a colon biopsy) for the level of the TAT-001 polypeptide where an aberrant level of the TAT-001 polypeptide is indicative of carcinoma. An “aberrant level” includes a level that is increased or decreased compared with the level in a subject free from cancer or a reference level.
In a further aspect, the method of detecting/quantifying the presence of a TAT-001 polypeptide comprises detecting the captured polypeptide using a directly or indirectly labelled detection reagent, e.g., a detectable marker such as, without limitation, a chemiluminescent, enzymatic, fluorescent, or radioactive moiety. If no labelled binding partner to the capture reagent is provided, the anti-TAT-001 polypeptide capture reagent itself can be labelled with a detectable marker (see above).
In a preferred embodiment, antibodies of the invention or fragments thereof are conjugated to a diagnostic or therapeutic moiety. The antibodies can be used for diagnosis or to determine the efficacy of a given treatment regimen. Detection can be facilitated by coupling the antibody to a detectable substance.
Examples of detectable substances include various enzymes, prosthetic groups, fluorescent materials, luminescent materials, bioluminescent materials, radioactive nuclides, positron emitting metals (for use in positron emission tomography), and non-radioactive paramagnetic metal ions (see U.S. Pat. No. 4,741,900 for metal ions which can be conjugated to antibodies for use as diagnostics according to the present invention). Suitable enzymes include horseradish peroxidase, alkaline phosphatase, beta-galactosidase, and acetylcholinesterase. Suitable prosthetic groups include streptavidin, avidin and biotin. Suitable fluorescent materials include umbelliferone, fluorescein, fluorescein isothiocyanate, rhodamine, dichlorotriazinylamine fluorescein, dansyl chloride and phycoerythrin. Suitable luminescent materials include luminol. Suitable bioluminescent materials include luciferase, luciferin, and aequorin. Suitable radioactive nuclides include I125, I131, In111 and Tc99.
The foregoing antibodies can be used in methods known in the art relating to the localization and activity of the TAT-001 polypeptides of the invention, e.g., for imaging or radio-imaging these proteins, measuring levels thereof in appropriate physiological samples, in diagnostic methods, etc. and for radiotherapy.
In certain embodiments, the assay is a two-antibody sandwich assay. This assay may be performed by first contacting an antibody that has been immobilized on a solid support, commonly the well of a microtiter plate, with the sample, such that polypeptides within the sample are allowed to bind to the immobilized antibody. Unbound sample is then removed from the immobilized polypeptide-antibody complexes and a detection reagent (preferably a second antibody capable of binding to a different site on the polypeptide) containing a reporter group is added. The amount of detection reagent that remains bound to the solid support is then determined using a method appropriate for the specific reporter group.
More specifically, once the antibody is immobilized on the support as described above, the remaining protein binding sites on the support are typically blocked. Any suitable blocking agent known to those of ordinary skill in the art, such as bovine serum albumin or Tween 20™ (Sigma Chemical Co., St. Louis, Mo.). The immobilized antibody is then incubated with the sample, and polypeptide is allowed to bind to the antibody. The sample may be diluted with a suitable diluent, such as phosphate-buffered saline (PBS) prior to incubation. In general, an appropriate contact time (i.e., incubation time) is a period of time that is sufficient to detect the presence of polypeptide within a sample obtained from an individual with (though not necessarily diagnosed a priori) colon cancer. Preferably, the contact time is sufficient to achieve a level of binding that is at least about 95% of that achieved at equilibrium between bound and unbound polypeptide. Preferably contact time sufficient to detect the presence of polypeptide within a normal control, if so expressed, is also permitted. Those of ordinary skill in the art will recognize that the time necessary to achieve equilibrium may be readily determined by assaying the level of binding that occurs over a period of time. At room temperature, an incubation time of about 30 minutes is generally sufficient.
Unbound sample may then be removed by washing the solid support with an appropriate buffer, such as PBS containing 0.1% Tween 20™. The second antibody, which contains a reporter group, may then be added to the solid support. Preferred reporter groups include those groups recited above.
The detection reagent is then incubated with the immobilized antibody-polypeptide complex for an amount of time sufficient to detect the bound polypeptide. An appropriate amount of time may generally be determined by assaying the level of binding that occurs over a period of time. Unbound detection reagent is then removed and bound detection reagent is detected using the reporter group. The method employed for detecting the reporter group depends upon the nature of the reporter group. For radioactive groups, scintillation counting or autoradiographic methods are generally appropriate. Spectroscopic methods may be used to detect dyes, luminescent groups and fluorescent groups. Biotin may be detected using avidin, coupled to a different reporter group (commonly a radioactive or fluorescent group or an enzyme). Enzyme reporter groups may generally be detected by the addition of substrate (generally for a specific period of time), followed by spectroscopic or other analysis of the reaction products.
To determine the presence or absence of a cancer, such as colon cancer, the signal detected from the reporter group that remains bound to the solid support is generally compared to a signal that corresponds to a cut-off value, preferably a predetermined cut-off value. In one preferred embodiment, the cut-off value for the detection of a cancer is the average mean signal obtained when the immobilized antibody is incubated with samples from patients without the cancer. In general, a sample generating a signal that is three standard deviations above the cut-off value is considered positive for the cancer. In an alternate preferred embodiment, the cut-off value is determined using a Receiver Operator Curve, according to the method of Sackett et al. (1985) Clinical Epidemiology: A Basic Science for Clinical Medicine, Little Brown and Co., p. 106-7. Briefly, in this embodiment, the cut-off value may be determined from a plot of pairs of true positive rates (i.e., sensitivity) and false positive rates (100% specificity) that correspond to each possible cut-off value for the diagnostic test result. The cut-off value on the plot that is the closest to the upper left-hand corner (i.e., the value that encloses the largest area) is the most accurate cut-off value, and a sample generating a signal that is higher than the cut-off value determined by this method may be considered positive. Alternatively, the cut-off value may be shifted to the left along the plot, to minimize the false positive rate, or to the right, to minimize the false negative rate. In general, a sample generating a signal that is higher than the cut-off value determined by this method is considered positive for a cancer.
In a related embodiment, the assay is performed in a flow-through or strip test format, wherein the binding agent is immobilized on a membrane, such as nitrocellulose. In the flow-through test, polypeptides within the sample bind to the immobilized binding agent as the sample passes through the membrane. A second, labeled binding agent then binds to the binding agent-polypeptide complex as a solution containing the second binding agent flows through the membrane. The detection of bound second binding agent may then be performed as described above. In the strip test format, one end of the membrane to which binding agent is bound is immersed in a solution containing the sample. The sample migrates along the membrane through a region containing second binding agent and to the area of immobilized binding agent. Concentration of second binding agent at the area of immobilized antibody indicates the presence of a cancer. Typically, the concentration of second binding agent at that site generates a pattern, such as a line, that can be read visually. The absence of such a pattern indicates a negative result. In general, the amount of binding agent immobilized on the membrane is selected to generate a visually discernible pattern when the biological sample contains a level of TAT-001 polypeptide that would be sufficient to generate a positive signal in the two-antibody sandwich assay, in the format discussed above. Preferred binding agents for use in such assays are antibodies and antigen-binding fragments thereof. Preferably, the amount of antibody immobilized on the membrane ranges from about 25 ng to about 1 μg, and more preferably from about 50 ng to about 500 ng. Such tests can typically be performed with a very small amount of biological sample.
Of course, numerous other assay protocols exist that are suitable for use with the TAT-001 polypeptides or binding agents of the present invention. The above descriptions are intended to be exemplary only. For example, it will be apparent to those of ordinary skill in the art that the above protocols may be readily modified to use TAT-001 polypeptides to detect antibodies that bind to such polypeptides in a biological sample. The detection of such TAT-001 specific antibodies may correlate with the presence of a cancer.
A cancer may also be detected based on the presence of T cells that specifically react with a TAT-001 polypeptide in a biological sample. Using known methods, a biological sample comprising CD4+ and/or CD8+ T cells isolated from a patient is incubated with a TAT-001 polypeptide, a polynucleotide encoding such a polypeptide and/or an antigen presentation complex (APC) that expresses at least an immunogenic portion of such a polypeptide, and the presence or absence of specific activation of the T cells is detected. Suitable biological samples include, but are not limited to, isolated T cells. For example, T cells may be isolated from a patient by routine techniques (such as by Ficoll/Hypaque density gradient centrifugation of peripheral blood lymphocytes). T cells may be incubated in vitro for 2-9 days (typically 4 days) at 37° C. with polypeptide (e.g., 5-25 μg/ml). It may be desirable to incubate another aliquot of a T cell sample in the absence of TAT-001 polypeptide to serve as a control. For CD4+ T cells, activation is preferably detected by evaluating proliferation of the T cells. For CD8+ T cells, activation is preferably detected by evaluating cytolytic activity. A level of proliferation that is at least two fold greater and/or a level of cytolytic activity that is at least 20% greater than in disease-free patients indicates the presence of a cancer in the patient.
In another embodiment, the compositions described herein may be used as markers for the progression of cancer. In this embodiment, assays as described above for the diagnosis of a cancer may be performed over time, and the change in the level of reactive polypeptide(s) or polynucleotide(s) evaluated. For example, the assays may be performed every 24-72 hours for a period of 6 months to 1 year, and thereafter performed as needed. In general, a cancer is advancing in those patients in whom the level of TAT-001 polypeptide or polynucleotide detected increases over time. In contrast, the cancer is not progressing when the level of reactive polypeptide or polynucleotide either remains constant or decreases with time.
Certain in vivo diagnostic assays may be performed directly on a tumor. One such assay involves contacting tumor cells with a binding agent. The bound binding agent may then be detected directly or indirectly via a reporter group. Such binding agents may also be used in histological applications. Alternatively, TAT-001 polynucleotide probes may be used within such applications.
As noted above, to improve sensitivity, multiple tumor protein markers in addition to TAT-001 may be assayed within a given sample. It will be apparent that binding agents specific for different proteins may be combined within a single assay. For example, such proteins may include: CD2 (GenBank GI #115975), CD3 (GenBank GI #1345708 (epsilon subunit)), CD4 (GenBank GI #116013), CD5 (GenBank GI #116024), CD8 (GenBank GI #116035), CD11c (GenBank GI #386831), CD14 (GenBank GI #29741), CD15 (GenBank GI #4503811), CD19 (GenBank GI #178667), CD20 (GenBank GI #115968), CD21 (GenBank GI #117315), CD22 (GenBank GI #29779), CD23 (GenBank GI #119862), CD25 (GenBank GI #124317), CD30 (GenBank GI #115978), CD33 (GenBank GI #115979), CD37 (GenBank GI #115983), CD38 (GenBank GI #180119), CD40 (GenBank GI #116000), CD44 (GenBank GI #950417), CD44v6 (CD44 isoforms containing variant exon 6, e.g., GenBank GI #48255937, GenBank GI #48255935), CD45 (GenBank GI #34281), CD46 (GenBank GI #262938), CD48 (GenBank GI #114871), CD51 (integrin αv) (GenBank GI #124959), CD52 (GenBank GI #3182945), CD54 (GenBank GI #124098), CD56 (GenBank GI #3334473), CD61 (integrin β3) (GenBank GI # 124968), CD66e (CEA) (GenBank GI #115940), CD70 (GenBank GI #545773), CD71 (transferrin receptor) (GenBank GI #136378), CD72 (GenBank GI #116029), CD74 (GenBank GI #10835071), CD80 (GenBank GI #461606), CD87 (uPAR) (GenBank GI #465003), CD95 (Apo-1, Fas) (GenBank GI #119833), CD97 (GenBank GI #42560541), CD98 (4F2) (GenBank GI #112803), CD105 (GenBank GI #182091), CD122 (GenBank GI #124321), CD126 (GenBank GI #124343), CD135 (Flt3) (GenBank GI #544320), CD144 (vascular endothelial cadherin) (GenBank GI #13432109), CD146 (MUC18) (GenBank GI #1171064), CD152 (CTLA4) (GenBank GI #27735177), CD154 (CD40L) (GenBank GI #38412), CD155 (GenBank GI #1346922), CD178 (CD95L) (GenBank GI #1345957), CD221 (insulin-like growth factor receptor 1) (GenBank GI #124240), CD224 (gamma glutamyl transferase) (GenBank GI #121148), CD227 (MUCI) (GenBank GI #547937), CD243 (MDR1) (GenBank GI #2506118), BAFF (GenBank GI #13124573), BAFF receptor (GenBank GI #21264093), BST2 (GenBank GI #1705508), endosialin (GenBank GI #9966885), HLA-DR beta (GenBank GI #188241), tenascin (GenBank GI #3915888), her2/neu (GenBank GI #119533), Muc16 (GenBank GI #34501467), G250 (GenBank GI #5915865), TweakR (GenBank GI # 21263626), PSMA (GenBank GI #548615), TRAIL-R1 (DR4) (GenBank GI #21264525), TRAIL-R2 (DR5) (GenBank GI #17380321), TP-1 antigen (Bruland et al. (1988) Cancer Res. 48: 5302-5309), 8H9 glycoprotein (Modak et al. (2001) Cancer Res. 61: 4048-4054), EGP-1 (TACSTD-2) (GenBank GI #1346075), KGF-2 (FGF-10) (GenBank GI #6015141), A33 antigen (GenBank GI #2842765), MCSP (GenBank GI #20141463), lactadherin (GenBank GI # 2506380), EphA2 (GenBank GI #125333), EphA4 (GenBank GI #1711371), EphB2 (GenBank GI #12644190), CCR4 (GenBank GI #1705894), E48 (GenBank GI #2501524), 5T4 fetal protein trophoblast (GenBank GI #435655), Muc5AC (GenBank GI #46397621), FAPA (GenBank GI #20140021), LTBR (GenBank GI #549090), CFR-1 (GenBank GI #17376711), PGRN (GenBank GI #121617), VEGFR-2 (GenBank GI #9087218), MOvl8 (GenBank GI # 544337), Cripto (GenBank GI #117473), Wnt-1 (GenBank GI #139743), Wnt-2 (GenBank GI # 4507927), parathyroid hormone-related peptide (GenBank GI #131542), scatter factor (GenBank GI #123116), EGF receptor (GenBank GI #2811086), TAG72 (Muraro et al. (1988) Cancer Res. 48: 4588-4596), CanAg (Baeckstrom et al. (1991) J Biol Chem. 266: 21537-21547 and GenBank GI #547937), C30.6 (Mount et al. (1994) Cancer Res. 54: 6160-6166), GD2 ganglioside (Nagata et al. (1992) J Biol Chem. 267: 12082-12089), GD3 ganglioside (Zou et al. (2004) J Biol Chem. 279: 25390-25399), adenocarcinoma Lewis Y antigen (Nudelman et aL. (1986) J Biol Chem. 261: 11247-11253; Kim et al. (1986) Cancer Res. 46: 5985-5992), Human carcinoma L6 carbohydrate (Hellstrom et al. (1986) Cancer Res. 46: 3917-3923; Fell et aL. (1992) J Biol Chem. 267:15552-15558), IL-8 (GenBank GI #124359), EpCam (TACSTD-1, EGP-2) (GenBank GI #120749), LI-CAM splice variant (Meli et aL. (1999) Int J Cancer. 83: 401-408; GenBank GI #4557707, 13435353), vitronectin (GenBank GI #139653), placental alkaline phosphatase (GenBank GI #130737), neuropilin (GenBank GI #9297107), and B-cell-tumor-associated antigens, including vascular endothelial antigens, such as vascular endothelial growth factor (VEGF) (GenBank GI #30172564) and placenta growth factor (PLGF) (GenBank GI #17380553), and the like. For brevity, the GenBank GI #s provided are intended as representative and may be considered a preferred sequence, however they are meant to encompass splice variants, variants, isoforms, polymorphisms, mutations, modifications, and the like, preferably those associated with cancer. Preferably such variant sequences have at least 90% sequence identity to the representative sequence, more preferably at least 95% sequence identity, or at least 96%, 97%, 98%, or 99% sequence identity. Proteins presented in their precursor form, are also preferred in their mature form. Proteins present in hetero- or homo-multimers may be probed for as individual proteins or as part of their multimeric complex (e.g., integrin αvβ3). Multimer subunits presented may be taken as more preferable subunits, but the other subunits and multimeric forms are also preferred. Further, multiple primers or probes may be used concurrently. The selection of tumor protein markers may be based on routine experiments to determine combinations that result in optimal sensitivity. In addition, or alternatively, assays for TAT-001 polypeptides and/or nucleic acids provided herein may be combined with assays for other known tumor antigens.
In addition, nucleic acid molecules encoding the polypeptides or fragments thereof may be used for diagnostic assays of the invention. The use of nucleic acid molecules which may hybridize to any of the TAT-001 nucleic acid molecules is included in the present invention. Such nucleic acid molecules are referred to herein as “hybridizing” nucleic acid molecules. Hybridizing nucleic acid molecules can be useful as probes or primers, for example, or in hybridization assays. Desirably such hybridizing molecules are at least 8 nucleotides in length and preferably are at least 25 or at least 50 nucleotides in length.
Hybridization assays can be used for detection, prognosis, diagnosis, or monitoring of conditions, disorders, or disease states, associated with aberrant expression of genes encoding a TAT-001 polypeptide, or for differential diagnosis of patients with signs or symptoms suggestive of cancer.
Desirably the hybridizing molecules will hybridize to TAT-001 nucleic acids under stringent hybridization conditions. One example of stringent hybridization conditions is where attempted hybridization is carried out at a temperature of from about 35° C. to about 65° C. using a salt solution (e.g., about 0.9 M salt solution). However, the skilled person will be able to vary such conditions as appropriate in order to take into account variables such as probe length, base composition, and type of ions present, etc. For a high degree of selectivity, relatively stringent conditions are used to form the duplexes, such as low salt or high temperature conditions. As used herein, “highly stringent conditions” means hybridization to filter-bound DNA in 0.5 M NaHP04, 7% sodium dodecyl sulphate (SDS), 1 mM EDTA at 65° C., and washing in 0. 1 X SSC/0.1% SDS at 68° C. (Ausubel et al., eds. (1989) Current Protocols in Molecular Biology, Vol. I, Green Publishing Associates, Inc., and John Wiley & Sons, Inc., New York). For some applications, less stringent conditions for duplex formation are required. As used herein “moderately stringent conditions” means washing in 0.2×SSC/0.1% SDS at 42° C. (Ausubel et al. (1989), supra). Hybridization conditions can also be rendered more stringent by the addition of increasing amounts of formamide, to destabilize the hybrid duplex. Thus, particular hybridization conditions can be readily manipulated, and will generally be chosen depending on the desired results. In general, convenient hybridization temperatures in the presence of 50% formamide are: 42° C. for a probe which is 95 to 100% identical to the fragment of a gene encoding a polypeptide as defmed herein, 37° C. for 90 to 95% identity and 32° C. for 70 to 90% identity.
A hybridizing nucleic acid molecule of use in the present invention may have a high degree of sequence identity along its length with a TAT-001 nucleic acid (e.g., at least 50%, at least 75%, at least 80%, at least 85%, at least 90%, 95%, or at least 98% sequence identity). As will be appreciated by the skilled person, the higher the sequence identity a given single stranded nucleic acid molecule has with another nucleic acid molecule, the greater the likelihood that it will hybridize to a nucleic acid molecule which is complementary to that other nucleic acid molecule under appropriate conditions. If desired, a gene encoding a TAT-001 polypeptide, a related gene, or a related TAT-001 nucleic acid sequence or sub-sequence, including complementary sequences, can also be used in hybridization assays. A TAT-001 nucleotide encoding a TAT-001 polypeptide, or sub-sequences thereof comprising at least 8 nucleotides, can be used as a hybridization probe.
Nucleic acid molecules encoding the TAT-001 polypeptides or fragments thereof can also be used to identify subjects having a genetic variation, mutation, or polymorphism in a TAT-001 nucleic acid molecule that is indicative of a cancer or a predisposition to develop cancer. These polymorphisms may affect TAT-001 nucleic acid or polypeptide expression levels or biological activity. Such genetic alterations may be present in the promoter sequence, an open reading frame, intronic sequence, or untranslated 3′ region of a TAT-001 gene. As noted throughout, specific alterations in the biological activity of TAT-001 can be correlated with the likelihood of cancer, e.g., colon cancer, or a predisposition to develop the same. As a result, one skilled in the art, having detected a given mutation, can then assay one or more metrics of the biological activity of the TAT-001 protein to determine if the mutation causes or or correlates with an increase in the likelihood of developing cancer.
Diagnostic Kits
The present invention further provides kits for use within any of the above diagnostic methods. Such kits typically comprise two or more components necessary for performing a diagnostic assay. Components may be compounds, reagents, containers and/or equipment. For example, one container within a kit may contain a monoclonal antibody or fragment that specifically binds a tumor protein. Such antibodies or fragments may be provided attached to a support material, as described above. One or more additional containers may enclose elements, such as reagents or buffers, to be used in the assay. Such kits may also, or alternatively, contain a detection reagent as described above that contains a reporter group suitable for direct or indirect detection of antibody binding.
Alternatively, a kit may be designed to detect the level of MRNA encoding a tumor protein in a biological sample. Such kits generally comprise at least one oligonucleotide probe or primer, as described above, that hybridizes to a polynucleotide encoding a tumor protein. Such an oligonucleotide may be used, for example, within a PCR or hybridization assay. Additional components that may be present within such kits include a second oligonucleotide and/or a diagnostic reagent or container to facilitate the detection of a polynucleotide encoding a tumor protein.
The invention also provides diagnostic kits, comprising a capture reagent (e.g., an antibody) against a TAT-001 polypeptide as defined above. In addition, such a kit may optionally comprise one or more of the following: (1) instructions for using the capture reagent for diagnosis, prognosis, therapeutic monitoring or any combination of these applications; (2) a labelled binding partner to the capture reagent; (3) a solid phase (such as a reagent strip) upon which the capture reagent is immobilized; and (4) a label or insert indicating regulatory approval for diagnostic, prognostic or therapeutic use or any combination thereof.
Pharmaceutical Compositions and Therapies
The invention also provides various immunogenic or therapeutic compositions and strategies for the prophylaxis and/or treatment of cancers that express TAT-001 such as colon cancers in a subject, including therapies aimed at inhibiting the transcription, translation, processing or finction of TAT-001 as well as cancer vaccines.
In another aspect, the present invention provides a method treatment of cancer in a subject, which comprises administering to said subject a therapeutically effective amount of at least one TAT-001 polypeptide.
In a yet another aspect, the present invention provides the use of at least one TAT-001 polypeptide in the preparation of a pharmaceutical composition for use in the prophylaxis and/or treatment of cancer. The subject may be a mammal and is preferably a human.
In a particular embodiment, a TAT-001 polypeptide is fused to another polypeptide, such as the protein transduction domain of the HIV/TAT protein, which facilitates the entry of the fusion protein into a cell (Asoh et al. (2002) Proc Natl Acad Sci. U.S.A. 99: 17107-17112), is provided for use in the manufacture of a pharmaceutical composition for the treatment of cancer.
In a another aspect, the present invention provides a method for the prophylaxis and/or treatment of cancer in a subject, which comprises administering to said subject a therapeutically effective amount of at least one TAT-001 nucleic acid.
In a yet another aspect, the present invention provides the use of at least one TAT-001 nucleic acid in the preparation of a pharmaceutical composition for use in the prophylaxis and/or treatment of cancer. The subject may be a mammal and is preferably a human.
The present invention provides a method for the treatment and/or prophylaxis of cancer in a subject comprising administering to said subject, a therapeutically effective amount of at least one antibody that binds to a TAT-001 polypeptide. In another aspect, the present invention provides the use of an antibody which binds to at least one TAT-001 polypeptide in the preparation of a pharmaceutical composition for use in the prophylaxis and/or treatment of cancer. In particular, the preparation of vaccines and/or compositions comprising or consisting of antibodies is a preferred embodiment of this aspect of the invention.
This invention further provides compounds identified by the above-described screening assays, TAT-001 polypeptides, and TAT-001 nucleic acids and uses thereof for treatments as described herein. Hereinafter, the compounds, TAT-001 polypeptides, antibodies thereto and TAT-001 nucleic acids of potential use in treatment are referred to as ‘anti-cancer agents’. The term ‘treatment’ includes either therapeutic or prophylactic therapy. When a reference is made herein to a method of treating or preventing a disease or condition using a particular anti-cancer agent or combination of agents, it is to be understood that such a reference is intended to include the use of that anti-cancer agent or combination of agents in the preparation of a medicament for the treatment or prevention of the disease or condition.
Accordingly, the present invention provides a method for the prophylaxis and/or treatment of cancer, which comprises administering to said subject a therapeutically effective amount of at least one anti-cancer agent of the invention.
In yet another aspect, the present invention provides a pharmaceutical composition comprising at least one anti-cancer agent of the invention, optionally together with one or more pharmaceutical acceptable excipients, carriers or diluents.
In order to use anti-cancer agent of the invention in therapy (human or veterinary), the agent will normally be formulated into a pharmaceutical composition in accordance with standard pharmaceutical practice, e.g., by admixing the active agent and a pharmaceutical acceptable carrier. Thus, according to a further aspect of the invention there is provided a pharmaceutical composition comprising at least one active agent of the invention and a pharmaceutical acceptable carrier. The pharmaceutical compositions are particularly useful in the prevention or treatment of cancer. In one aspect, the pharmaceutical composition is for use as a vaccine and so any additional components will be acceptable for vaccine use. In addition, the skilled person will appreciate that one or more suitable adjuvants may be added to such vaccine preparations. Pharmaceutical acceptable carriers for use in the invention may take a wide variety of forms depending, e.g., on the route of administration.
Thus, the pharmaceutical compositions described herein may be used for the treatment of cancer, particularly for the immunotherapy of colon cancer. Within such methods, the pharmaceutical compositions described herein are administered to a patient. A patient may or may not be afflicted with cancer. Accordingly, the pharmaceutical compositions herein may be used to prevent the development of a cancer or to treat a patient afflicted with a cancer. Pharmaceutical compositions and vaccines may be administered either prior to or following surgical removal of primary tumors and/or treatment such as administration of radiotherapy or conventional chemotherapeutic drugs. Administration of the pharmaceutical compositions may be by any suitable method, including administration to a subject by any of the routes conventionally used for drug administration, for example they may be administered parenterally, orally, topically (including buccal, sublingual or transdermal), intravenously, intraperitoneally, intramuscularly, subcutaneously, intranasally, intradermally, anally, vaginally, topically, and by oral routes or by inhalation. The most suitable route for administration in any given case will depend on the particular active agent, the cancer involved, the subject, and the nature and severity of the disease and the physical condition of the subject.
Compositions for oral administration may be liquid or solid. Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups or elixirs, or may be presented as a dry product for reconstitution with water or other suitable vehicle before use. Oral liquid preparations may contain suspending agents, for example sorbitol, methyl cellulose, glucose syrup, gelatin, hydroxyethyl cellulose, carboxymethyl cellulose, aluminium stearate gel or hydrogenated edible fats, emulsifying agents, for example lecithin, sorbitan monooleate, or acacia; water; non-aqueous vehicles (which may include edible oils), for example almond oil, oily esters such as glycerine, propylene glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoate or sorbic acid; flavoring agents, preservatives, coloring agents and the like may also be used.
In the case of oral solid preparations such as powders, capsules and tablets, carriers such as starches, sugars, microcrystalline cellulose, diluents, granulating agents, lubricants, binders, disintegrating agents, and the like may be included. Because of their ease of administration, tablets and capsules represent the most advantageous oral dosage unit form in which case solid pharmaceutical carriers are generally employed. In addition to the common dosage forms set out above, active agents of the invention may also be administered by controlled release means and/or delivery devices. Tablets and capsules may comprise conventional carriers or excipients such as binding agents for example, syrup, acacia, gelatin, sorbitol, tragacanth, or polyvinylpyrrolidone; fillers (e.g., lactose, sugar, maize-starch, calcium phosphate, sorbitol or glycine); tableting lubricants (e.g., magnesium stearate, talc, polyethylene glycol or silica); disintegrants (e.g., potato starch); or acceptable wetting agents such as sodium lauryl sulphate. The tablets may be coated by standard aqueous or non-aqueous techniques according to methods well known in normal pharmaceutical practice.
Pharmaceutical compositions of the present invention suitable for oral administration may be presented as discrete units such as capsules, cachets or tablets, each containing a predetermined amount of the active agent, as a powder or granules, or as a solution or a suspension in an aqueous liquid, a non-aqueous liquid, an oil-in-water emulsion or a water-in-oil liquid emulsion. Such compositions may be prepared by any of the methods of pharmacy but all methods include the step of bringing into association the active agent with the carrier, which constitutes one or more necessary ingredients. In general, the compositions are prepared by uniformly and intimately admixing the active agent with liquid carriers or fmely divided solid carriers or both, and then, if necessary, shaping the product into the desired presentation. For example, a tablet may be prepared by compression or moulding, optionally with one or more accessory ingredients.
Compressed tablets may be prepared by compressing, in a suitable machine, the anti- cancer agent in a free-flowing form such as a powder or granules, optionally mixed with a binder, lubricant, inert diluent, surface active or dispersing agent. Moulded tablets may be made by moulding, in a suitable machine, a mixture of the powdered compound moistened with an inert liquid diluent. Desirably, each tablet contains from about 1 mg to about 500 mg of the active agent and each cachet or capsule contains from about 1 to about 500 mg of the active agent.
Compositions comprising an anti-cancer agent of the invention may also be prepared in powder or liquid concentrate form. Conventional water soluble excipients, such as lactose or sucrose, may be incorporated in the powders to improve their physical properties. Thus, particularly suitable powders of this invention comprise 50 to 100% w/w, and preferably 60 to 80% w/w of the combination and 0 to 50% w/w and preferably 20 to 40% w/w of conventional excipients. When used in a veterinary setting such powders may be added to animal feedstuffs, for example by way of an intermediate premix, or diluted in animal drinking water.
Liquid concentrates of this invention for oral administration suitably contain a water- soluble compound combination and may optionally include a pharmaceutically acceptable water miscible solvent, for example polyethylene glycol, propylene glycol, glycerol, glycerol formal or such a solvent mixed with up to 30% v/v of ethanol. The liquid concentrates may be administered to the drinking water of animals.
Pharmaceutical compositions suitable for parenteral administration may be prepared as solutions or suspensions of the active agents of the invention in water suitably mixed with a surfactant such as hydroxypropylcellulose. Dispersions can also be prepared in glycerol, liquid polyethylene glycols, and mixtures thereof in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms.
The pharmaceutical forms suitable for injectable use include aqueous or non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the composition isotonic with the blood of the intended recipient, and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. Extemporaneous injection solutions, dispersions and suspensions may be prepared from sterile powders, granules and tablets.
The compositions may be presented in unit-dose or multi-dose containers, for example in sealed ampoules and vials and to enhance stability, may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. The sterile liquid carrier may be supplied in a separate vial or ampoule and can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (e.g., glycerol, propylene glycol and liquid polyethylene glycol), suitable mixtures thereof, and vegetable oils. Advantageously, agents such as a local anaesthetic, preservative and buffering agents can be included the sterile liquid carrier.
In certain embodiments, the anti-cancer agents of the invention can be formulated to ensure proper distribution in vivo, for example, in liposomes. For methods of manufacturing liposomes; see, for example, U.S. Pat. Nos. 4,522,811; 5,374,548; and 5,399,331. The liposomes may comprise one or more moieties which are selectively transported into specific cells or organs, thus enhancing targeted drug delivery (see, e.g., Ranade (1989) J Clin Pharmacol. 29: 685-694).
Exemplary targeting moieties include folate or biotin (see, e.g., U.S. Pat. No. 5,416,016); mannosides (Umezawa and Eto (1988) Biochem Biophys Res Comm. 153: 1038-1044); antibodies (Bloemen et al. (1995) FEBS Lett. 357: 140-144; Owais et al. (1995) Antimicrob Agents Chemother. 39: 180-184); surfactant protein A receptor (Briscoe et al. (1995) Am J Physio. 268: 374-380), different species of which may comprise the compositions of the inventions, as well as components of the invented molecules; psi 20 (Schreier et al. (1994) J Biol Chem. 269: 9090-9098); see also Keinanen and Laukkanen (1994) FEBS Lett. 346: 123-126; and Killion and Fidler (1994) Immunomethods 4: 273-279. In one embodiment of the invention, the anti-cancer agents of the invention are formulated in liposomes; in a more preferred embodiment, the liposomes include a targeting moiety. In a most preferred embodiment, the therapeutic compounds in the liposomes are delivered by bolus injection to a site proximal to the tumor.
Pharmaceutical compositions adapted for topical administration may be formulated as ointments, creams, suspensions, lotions, powders, solutions, pastes, gels, impregnated dressings, sprays, aerosols or oils, transdermal devices, dusting powders, and the like. These compositions may be prepared via conventional methods containing the anti-cancer agent. Thus, they may also comprise compatible conventional carriers and additives, such as preservatives, solvents to assist drug penetration, emollient in creams or ointments and ethanol or oleyl alcohol for lotions. Such carriers may be present as from about 1% up to about 98% of the composition. More usually they will form up to about 80% of the composition. For example, a cream or ointment may be prepared by mixing sufficient quantities of hydrophilic material and water, containing from about 5-10% by weight of the compound, in sufficient quantities to produce a cream or ointment having the desired consistency.
Pharmaceutical compositions adapted for transdermal administration may be presented as discrete patches intended to remain in intimate contact with the epidermis of the recipient for a prolonged period of time. For example, the anti-cancer agent may be delivered from the patch by iontophoresis. For applications to external tissues, for example the mouth and skin, the compositions are preferably applied as a topical ointment or cream. When formulated in an ointment, the anti-cancer agent may be employed with either a paraffinic or a water-miscible ointment base. Alternatively, the anti-cancer agent may be formulated in a cream with an oil-in- water cream base or a water-in-oil base. Pharmaceutical compositions adapted for topical administration in the mouth include lozenges, pastilles and mouth washes.
Pharmaceutical compositions adapted for topical administration to the eye include eye drops wherein the active agent is dissolved or suspended in a suitable carrier, especially an aqueous solvent. They also include topical ointments or creams as above.
Pharmaceutical compositions suitable for rectal administration wherein the carrier is a solid are most preferably presented as unit dose suppositories. Suitable carriers include cocoa butter or other glyceride or materials commonly used in the art, and the suppositories may be conveniently formed by admixture of the combination with the softened or melted carrier(s) followed by chilling and shaping moulds. They may also be administered as enemas.
Pharmaceutical compositions adapted for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray compositions. These may comprise emollient or bases as commonly used in the art.
Pharmaceutical compositions may be conveniently presented in unit dose forms containing a predetermined amount of an active agent of the invention per dose. For example, the compositions may contain from 0.1% by weight, preferably from 10-60% by weight, of the active agent of the invention, depending on the method of administration. The dosage to be administered of an active agent may vary according to several factors, including, but not limited to, the particular active agent, the cancer involved, the subject, the nature and severity of the disease and the physical condition of the subject, and the selected route of administration; the appropriate dosage can be readily determined by a person skilled in the art. For prophylactic or therapeutic use in humans and animals, a dosage unit may contain, for example, but without limitation, 0.001 mg/kg to 750 mg/kg of active agent, depending on factors such as those aforementioned. Preferred unit dosage compositions are those containing a daily dose or sub-dose, as recited above, or an appropriate fraction thereof, of the anti-cancer agent.
It will be recognized by one of skill in the art that the optimal quantity and spacing of individual dosages of an anti-cancer agent of the invention will be determined by the nature and extent of the condition being treated, the form, route and site of administration, and the particular subject being treated, and that such optimums can be determined by conventional techniques. It will also be appreciated by one of skill in the art that the optimal course of treatment, i.e. the number of doses of an active agent of the invention given per day for a defined number of days, can be ascertained by those skilled in the art using conventional course of treatment determination tests.
In a particular embodiment, a therapeutically effective amount of an agent can be determined by monitoring an amelioration or improvement in disease symptoms, to delay onset or slow progression of the disease, for example but without limitation, a reduction in tumor size. Preferably such improvements in disease symptoms are by at least 0.1%, at least 1%, at least 5%, or at least 10%. More preferably, such improvements are by at least 25%, at least 50%, at least 75%,or at least 90%. Most preferably, such improvements are by at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%. Dosage regimens can be adjusted to provide the optimum desired response (for example, see Hardman and Limbird (eds.) (2001) Goodman & Gilman's The Pharmacological Basis of Therapeutics, 10th edition, McGraw Hill, New York; Beers and Berkow (eds.) (1999) The Merck Manual, 17th edition, Merck Research Laboratories, Whitehouse Station, N.J.). For example, a single bolus may be administered, several divided doses may be administered over time or the dose may be proportionally reduced or increased as indicated by the exigencies of the therapeutic situation. Techniques known to physicians familiar with cancer can be used to determine whether a candidate agent has altered one or more symptoms associated with the disease. In general, an appropriate dosage and treatment regimen provides the active compound(s) in an amount sufficient to provide therapeutic and/or prophylactic benefit. Such a response can be monitored by establishing an improved clinical outcome (e.g., more frequent remissions, complete or partial, or longer disease-free survival) in treated patients as compared to non-treated patients. Increases in preexisting immune responses to a tumor protein generally correlate with an improved clinical outcome. Such immune responses may generally be evaluated using standard proliferation, cytotoxicity or cytokine assays, which may be performed using samples obtained from a patient before and after treatment. Such response can also be monitored by measuring the anti-TAT-001 antibodies in a patient or by vaccine-dependent generation of cytolytic effector cells capable of killing the patient's tumor cells in vitro. Such vaccines should also be capable of causing an immune response that leads to an improved clinical outcome (e.g., more frequent remissions, complete or partial or longer disease-free survival) in vaccinated patients as compared to non-vaccinated patients.
The present invention also features a combination therapy involving the use of a TAT-001 antibody or a TAT-001 vaccine, and that further includes administration to the patient an additional treatment for cancer, with the additional treatment administered within six months of administering the TAT-001 antibody or TAT-001 vaccine. In one embodiment, one or more anti-cancer agents are administered alone or in combination (e.g., simultaneously, sequentially or separately) with one or more additional treatments or therapeutic compounds for cancer and/or symptoms or conditions related to the treatment thereof, wherein at least one of the therapies involves TAT-001 peptides, TAT-001 nucleic acids, TAT-001 antibodies, TAT-001 binding molecules, or TAT-001 vaccines. The additional treatment can be, but is not limited to, surgery, radiation therapy, chemotherapy, immunotherapy, anti-angiogenesis therapy, or gene therapy. Preferably, the additional treatment is chemotherapy with an anti-proliferative agent. Most preferably, the additional treatment includes administering to a patient an anti-proliferative agent. Exemplary antiproliferative agents include bleomycin, carmustine, cisplatin, daunorubicin, etoposide, melphalan, mercaptopurine, methotrexate, mitomycin, vinblastine, paclitaxel, docetaxel, vincristine, vinorelbine, cyclophosphamide, chlorambucil, gemcitabine, capecitabine, 5-fluorouracil, fludarabine, raltitrexed, irinotecan, topotecan, doxorubicin, epirubicin, letrozole, anastrazole, formestane, exemestane, tamoxifen, toremofme, goserelin, leuporelin, bicalutamide, flutamide, nilutamide, hypericin, trastuzumab, or rituximab, or any combination thereof.
Examples of other preferable contemplated treatments for use in combination with TAT-001-based treatments (see, for additional examples, Goodman & Gilman's The Pharmacological Basis of Therapeutics, supra, Chapter 52) include, surgery and radiation therapy. Examples of additional preferred therapeutic compounds for use in combination with TAT-001-based treatments include, but are not limited to, alkylating agents, such as nitrogen mustards, ethylenimines, methylmelamines, alkyl sulfonates, nitrosoureas, and triazenes; antimetabolites, such as folic acid analogs, pyrimidine analogs, and purine analogs and related inhibitors; natural products, such as vinca alkaloids, taxanes, epipodophyllotoxins, camptothecins; platinum coordination complexes, such as cisplatin; hydroxyurea, and hormones and antagonists, such as adrenocorticosteroids, progestins, estrogens, antiestrogen, androgens, antiandrogens, and gonadotropin-releasing hormone analogs; cyclophosphamide (cytoxan™); methotrexate (methotrexate™); 5-fluorouracil (5-FU); paclitaxel (Taxol); docetaxel (taxotere™); vincristine (oncovin™); imatinib (STI-571, Gleevec™); vinblastine (velban™); vinorelbine (navelbine™); doxorubicin (Adriamycin); tamoxifen (nolvadex™); toremifene (fareston™); megestrol acetate (megace); anastrozole (arimide) (1M); goserelin (zoladex™); anti-HER2 monoclonal antibody (herceptin™); anti-CD20 monoclonal antibodies (Rituxan™, Zevalin™, and/or Bexxar™); anti-CD33 monoclonal antibody (Mylotarg™); anti-CD52 monoclonal antibody (Campath™); anti-VEGF-A monoclonal antibody (Avastin™); anti-EpCAM monoclonal antibody (Panorex™); anti-EGF receptor monoclonal antibody (Erbitux™and/or Matuzumab™); capecitabine (xeloda™); and raloxifene hydrochloride (vista).
When the additional treatment is a chemotherapy, the chemotherapeutic and the TAT-001 antibody and/or TAT-001 vaccine can be administered within 14 days of each other. Preferably, a combination treatment is administered within ten days of each other, more preferably within five days of each other, and most preferably within twenty-four hours of each other or even simultaneously. A chemotherapeutic agent of the invention is usually given by the same route of administration that is known to be effective for delivering it as a monotherapy. For example, when used in combination therapy with the TAT-001 antibody or TAT-001 vaccine or both according to the methods of this invention, a chemotherapeutic agent is dosed in amounts and frequencies equivalent to or less than those that result in its effective monotherapeutic use.
Combination therapy may be provided wherever chemotherapy is performed: at home, the doctor's office, a clinic, a hospital's outpatient department, or a hospital. Treatment generally begins at a hospital so that the doctor can observe the therapy's effects closely and make any adjustments that are needed. The duration of the combination therapy depends on the kind of neoplasm being treated, the age and condition of the patient, the stage and type of the patient's disease, and how the patient's body responds to the treatment. Drug administration may be performed at different intervals (e.g., daily, weekly, or monthly) and the administration of each agent can be determined individually. Combination therapy may be given in on-and-off cycles that include rest periods so that the patient's body has a chance to build healthy new cells and regain its strength.
Depending on the type of neoplasm and its stage of development, the combination therapy can be used to treat the neoplasm, for example, colon cancer, to slow the spreading of the colon cancer, to slow the colon cancer's growth, to kill or arrest colon cancer cells that may have spread to other parts of the body from the original tumor, to relieve symptoms caused by the colon cancer, or to prevent colon cancer in the first place. Combination therapy can also help people live more comfortably by eliminating colon cancer cells that cause pain or discomfort.
The administration of a combination of the present invention allows for the administration of lower doses of each compound, providing similar efficacy and lower toxicity compared to administration of either compound alone. Alternatively, such combinations result in improved efficacy in treating neoplasms with similar or reduced toxicity.
An experiment was conducted using a complex human tissue sample and the sample was processed (solubilized and fractionated by 1D SDS polyacrylamide gel electrophoresis (PAGE)). The gels were cut into 24 equal bands and each band was digested with trypsin to obtain peptides for analysis by nano-liquid chromatography-mass spectrometry (LC-MS)) to provide a total of 15 injections into the mass spectrometer after pooling. Each peptide fraction was injected onto a reverse phase capillary nano-liquid chromatography C18 column, coupled by electrospray to a QTOF (quadrapole time of flight) mass spectrometer. Peptide maps were derived for each of the 15 LC-MS isotope maps and all pairwise alignments between peptide maps were performed according to methods found in “Constellation Mapping and Uses Thereof” (PCT publication number WO 2004/049385, U.S. patent application publication number 20040172200; hereinafter “Constellation Mapping”).
The reproducibility of peptide matching results for the 15 injections of the same sample are summarized in
The variance in peptide intensity results are summarized in
A controlled experiment was conducted where 3 proteins were spiked into a complex sample at 14 different concentrations, from 1.25 fmoles to 500 fmoles, each in triplicate yielding 42 samples that were analyzed by LC-MS. For each of the 3 proteins, 10 peptides were identified in each sample and their intensities recorded. Peptide intensity was derived from the height of the peptide peak within the LC-MS data.
All differential protein abundance (dA) ratios and corresponding differential peptide intensity (dI) ratios were obtained.
Intensities were acquired from mouse plasma samples for three different hemoglobin tryptic peptides by mass spectrometry using Constellation Mapping and Mass Intensity Profiling System (PCT Publication No. WO 03/042774 and US Publication No. 20030129760; hereinafter “MIPS”) software. Briefly, proteins from the plasma samples were solubilized and fractionated by 1D SDS-PAGE. Gels were cut into 24 equal bands and each band was digested by trypsin to obtain peptides for analysis by nano-LC-MS. Each peptide fraction was injected onto a reverse phase capillary nano-liquid chromatography C18 column, coupled by electrospray to a QTOF mass spectrometer.
Plasma samples were subjected, in parallel, to proteomics analysis through a pair-wise comparison of the samples using MIPS and Constellation Mapping softwares. The analyses yielded isotope maps (see Constellation Mapping) in which thousands of peptide ions were visible, separated by retention time and a mass/charge ratio. Each isotope map was converted to a peptide map with each complex peptide isotope signature replaced by a single point, represented by the mass, charge, retention time, and intensity of that peptide. A nonlinear and dynamic retention time correction procedure was devised (see Constellation Mapping) to match the retention time when comparing two or more samples. The retention time correction procedure was based on pattern matching at each time point, resulting in the ability to accommodate even highly erratic behavior. Also identified in this process were those peptides unique to one sample or the other.
Peptide matching between samples was followed by a determination of relative intensity for each peptide, the automated calculation of which involved a form of the MIPS technology. (While each peptide has a unique ionization potential, making determination of absolute abundance difficult, the relative abundance of a peptide is directly related to its concentration in samples of similar complexity.) Peptide data was also later subjected to manual validation to correct potential errors in peptide matching. (Failures in peptide matching are largely due to peptide collision or heavily populated regions of the peptide maps.)
LC-MS/MS analysis of the samples was used in peptide sequence determination. Parent protein identification proceeded through Mascot (Matrix Science, Boston, MA) and BLAST (Altschul et al. (1997) Nucleic Acids Res. 25: 3389-3402; Altschul et al. (1990) J Mol Biol. 215: 403-410), and identified hemoglobin spectra were manually validated to confirm correct sequence assignment to the spectra. The three peptides represented in
Hemoglobin levels for the same samples were also determined for comparison by an independent assay based on the catalytic activity of hemoglobin in the oxidation of TMB (tetramethyl benzidine) in the presence of peroxide (Standefer and Vanderjagt (1977) Clin Chem. 23: 749). Briefly, 50 ml tubes were labeled for each sample and placed on ice. Two additional 50 ml tubes were also prepared and placed on ice: one a blank, one a control. The control was a pooled rat plasma (Pel-Freez Biologicals, Rogers, AR; catalog number 36142) of known hemoglobin content, used as a standard to calculate the hemoglobin content of the unknown samples: (Control concentration X OD600)/unknown sample OD600. Two ml of TMB 1-Component Microwell Peroxidase Substrate solution (KPL, Gaithersburg, Md.; catalog number 52-00-02) was added to all the labeled tubes, followed by addition of 10 μl of control plasma sample or plasma samples sequentially to their respective labeled tube(s). The tube labeled ‘Blank’ did not contain any plasma. Note that the time interval between additions of two consecutive plasma samples was one minute. Samples were vortexed for 2 seconds at maximum speed, then left at ambient temperature for 10 minutes. A BeckmanCoulter DU640B spectrophotometer was zeroed with the Blank sample at 600 nm wavelength, after ensuring that the lamp was turned on at least 20 minutes prior to reading. Samples were transferred into disposable cuvettes after 10 minutes, and the absorbance read at 600 nm. As seen in these results (
Tumor and normal epithelial cells were obtained from fresh colon resections from 30 individuals. Purified plasma membrane (20 μg) was obtained from each matching sample through the use of magnetic beads, coated with antibodies specific for epithelial cell plasma membrane proteins. Procedures were essentially as described in “Preparation of Highly Purified Plasma Membranes” (PCT publication number WO 03/025565, U.S. patent application publication number 20030064359) with some modifications.
Briefly, cell suspensions were prepared in parallel for a human colon cancer tissue biopsy and adjacent normal tissue by dissolving in an enzymatic solution that included collagenase and elastase (Worthington Tissue Dissociation Guide, Worthington Biochemical Corp., Freehold, N.J., 1990) in order to obtain dissociated cells. Three blocks of tissue from each matched normal and tumor specimen were also kept for RNA extraction. Each block weighed approximately 50 mg, and was archived in RNAlater (Sigma-Aldrich; Product code R0901) at −80° C. After counting with a hemocytometer, the cell suspensions were prepared for immunoisolation with a combination of antibodies. Microbeads (MACS Goat anti-mouse IgG MicroBeads (Miltenyi Biotec, Auburn, Calif., Catalog Number 48-401) were used to isolate the epithelial cells, and the cells were then disrupted using a Parr bomb (Parr cell disruption bomb: Parr Instrument Company, model number 4639). Epithelial plasma membranes were recovered using an LS separation column (Miltenyi Biotec, Catalog Number 42-401) was placed on a MidiMACS separation unit (magnet) (Miltenyi Biotec, Catalog Number 42-302) followed by the positive (magnetic) fraction eluant being transferred to a SW 60 Ti ultracentrifuge tube (Optima Ultracentrifuge: Beckman Coulter, Model XL-100K; Ultracentrifuge rotor type SW 60 Ti: Beckman Coulter; Ultra-clear centrifuge tubes (4 mL): Beckman, Catalog Number 344062), and a cushion of 50 μL 33% (1.28 M) sucrose placed at the bottom of the tube. The sample was centrifuged at 50,000 rpm for 30 minutes at 4° C. to pellet the membranes, and the supernatant removed (including the sucrose cushion). The pellet was resuspended in 100 μL ST/antiprotease with a micropipettor and gentle vortexing and prepared for SDS-PAGE. Proteins from plasma membrane fractions from normal and tumor tissues were solubilized and fractionated by 1D SDS polyacrylamide gel electrophoresis (PAGE). Gels were cut into 24 equal bands and each band was digested by trypsin to obtain peptides for analysis by nano-liquid chromatography-mass spectrometry (LC-MS). Each peptide fraction was injected onto a reverse phase capillary nano- liquid chromatography C18 column, coupled by electrospray to a QTOF (quadrapole time of flight) mass spectrometer.
In addition, tumor and normal purified plasma membrane was subjected, in parallel, to proteomics analysis through a pair-wise comparison of samples from a single individual using MIPS and Constellation Mapping softwares. The analyses yielded isotope maps in which thousands of peptide ions were visible, separated by retention time and a mass/charge ratio. Each isotope map was converted to a peptide map with each complex peptide isotope signature replaced by a single point, represented by the mass, charge, retention time, and intensity of that peptide. A nonlinear and dynamic retention time correction procedure was devised to match the retention time when comparing two or more samples. The retention time correction procedure was based on pattern matching at each time point, resulting in the ability to accommodate even highly erratic behavior. Also identified in this process were those peptides unique to one sample or the other.
Peptide matching between samples was followed by a determination of relative intensity for each peptide and its automated calculation involved a form of the MIPS technology. (While each peptide has a unique ionization potential, making determination of absolute abundance difficult, the relative abundance of a peptide is directly related to its concentration in samples of similar complexity.) Peptide data was also later subjected to manual validation to correct potential errors in peptide matching. (Failures in peptide matching are largely due to peptide collision or heavily populated regions of the peptide maps.)
Most of the peptides appeared in each injection and their relative abundance varied with a standard deviation of the mean of only 14%. Such tightly reproducible results allowed for the reliable detection of only slight differences between colon samples. Intensity differences of two-fold were readily detected across many patient samples. Differentially expressed peptides were subjected to manual MS to MS peptide-matching validation to ensure that the target peptides were matched correctly and expressed at the expected levels in the group and time point comparisons of interest (see
Once all patient samples were processed, a cross-study analysis was performed to identify those peptides determined to be over-expressed at a minimum pre-determined threshold level in a minimum pre-determined percentage of patients. For example, in the analysis of the thirty patient matched colon tumor and normal samples, 106,547 peptides were observed, 21,720 peptides of which were reproducibly observed in 30% or more of the study patients. Of these, 1509 were seen to be at least ten-fold up-regulated in over 30% of the patients, 2704 at least five-fold, and 3697 at least three-fold. Over 82% of all the peptides which were reproducible in 30% or more of the patients differed by less than three-fold between tumor and normal. Peptides identified as over-expressed under these criteria, which were also met by peptides from twenty out of a group of twenty-six previously identified immunotherapy targets known to be overexpressed in colon cancer, or identified as overexpressed under other criteria stringencies were subjected to targeted LC-MS/MS analysis for sequence determination if MS/MS had not been previously acquired (see
In this analysis peptide #1 (study peptide 21—177, amino acid sequence NQSLIPLLLEAR, SEQ ID NO: 1) and peptide #2 (study peptide 21—367, amino acid sequence FSQIELMR, SEQ ID NO: 3) were identified as peptides differentially expressed at least 3-fold (1.9 fold differential intensity corresponding to 3-fold differential abundance) between normal and tumor colon samples in 30% or more of the 30 pairs of patient samples examined (see
As a plasma membrane protein differentially expressed at a higher level in tumor cells as compared to adjacent normal cells, TAT-001 (SEQ ID NO: 5 (or SEQ ID NO: 8), see
TAT-001 encoding nucleic acids (e.g., SEQ ID NO: 2, 4, 6, 7, 9, 13, 14, 16, 17, 19, 20, 22, 23, 26, 29, 30, and 33) may be obtained by methods known in the art and from other readily available sources. For example, I.M.A.G.E. Consortium clones (ATCC, Manassas, Va.) containing a TAT-001 nucleic acid sequence (for example, EST Accession Number CV028817) may be ordered and sequenced using appropriate primers and methods known in the art (see, for example, Glover and Hames, DNA Cloning 1: Core Techniques, New York 1995, Roe et al., DNA Isolation and Sequencing, New York, 1996 or Sambrook et al., Molecular Cloning: A Laboratorv Manual, Vols. 1, 2, and 3, Cold Spring Harbor Laboratory Press, NY, 1989). A coding sequence is illustrated in
Alternatively, primers may be designed based on the ends or any facilitating intervening sequences of a TAT-001 GenBank sequence (with or without flanking sequences such as introduced restriction sites) to amplify TAT-001 nucleic acids by PCR from a human cDNA library using appropriate temperatures and cycle times for the nucleic acid sequences.
A cDNA library and 5′-RACE and/or 3′-RACE can be used to obtain clones encoding portions of previously uncloned regions. RACE (Rapid Amplification of cDNA Ends; see, e.g., M. A. Frohman, “RACE: Rapid Amplification of cDNA Ends,” in Innis et al. (eds) (1990) PCR Protocols: A Guide to Methods and Applications, pp. 28-38; and Frohman et al. (1988) Proc Natl Acad Sci. U.S.A. 85: 8998-9002) is used to generate material for sequence analysis and subcloning if necessary.
Genomic and cDNA libraries may also be screened to identify any libraries that contain the TAT-001 gene (e.g., SEQ ID NO: 10, 24, 27, 31, or 34) or closely related genes or sequences. In the preparation of genomic libraries, for example, DNA fragments are generated, some of which will encode parts or the whole of a polypeptide as defined herein. The DNA may be cleaved at specific sites using various restriction enzymes. For example, one may use DNAse in the presence of manganese to fragment the DNA, or the DNA may be physically sheared, as for example, by sonication. The DNA fragments may then be separated according to size by standard techniques, including but not limited to agarose and polyacrylamide gel electrophoresis, column chromatography and sucrose gradient centrifugation. The DNA fragments may then be inserted into suitable vectors, including but not limited to plasmids, cosmids, bacteriophages lambda or T4, and yeast artificial chromosomes (Yacs) (see, for example, Sambrook et al. (1989) Molecular Cloning, a Laboratory Manual, 1 st Ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York; Glover, D. M. (Ed.) (1985) DNA Cloning: A Practical Approach, MRL Press, Ltd., Oxford, U.K. Vol. L, Li; Ausubel F. M. et al. (Eds.) (1989) Current Protocols in Molecular Biology, Vol. 1, Green Publishing Associates, Inc., and John Wiley & Sons, Inc., New York). The genomic library may be screened by nucleic acid hybridization to labelled probe (Benton and Davis (1977) Science 196: 180-182; Grunstein and Hogness (1975) Proc Natl Acad Sci. U.S.A. 72: 3961-3965).
Dot blot hybridization (Leary et al. (1983) Proc Natl Acad Sci. U.S.A. 80: 4045-4049; Grunstein and Hogness (1975) Proc Natl Acad Sci. U.S.A. 72: 3961-3965; Benton and Davis (1977) Science 196: 180-182) may be performed to pre-screen libraries. Positive libraries may then be screened by colony or plaque hybridization to obtain genomic and/or cDNA versions of the TAT-001 gene (see, for example, Glover and Hames (1995) DNA Cloning 1: Core Techniques, New York; Roe et al. (1996) DNA Isolation and Sequencing, New York; or Sambrook et al. (1989) Molecular Cloning: A Laboratory Manual, Vols. 1, 2, and 3, Cold Spring Harbor Laboratory Press, NY).
TAT-001 nucleic acid sequences may be used as linearized DNA for direct in vitro translation, or may be subloned into vectors such as plasmids or viral vectors. Such vectors have use in producing TAT-001 proteins and nucleic acids as well as phenotypes associated with their expression, or inhibition thereof such as in a transgenic “knockout” mouse, but are not limited to these uses. PCR, incorporation of restriction sites, and the like for use in subcloning into vectors may be found for example in Sambrook et al., Molecular Cloning: A Laboratory Manual, Vols. 1, 2, and 3, Cold Spring Harbor Laboratory Press, NY, 1989.
An expression vector, in this embodiment utilizing pGEX-2T (Product #27-4801-01, Amersham Biosciences, San Francisco) as a backbone, comprising the sequence of
Briefly, in one working example, the vector in
Similarly a HIS-tag expression vector, such as pET-45b from Novagen (San Diego) is produced using primers to incorporate a Kpnl flanking the TAT-001 coding sequence and keeping it in-frame with the HIS-tag. Baculovirus (Pharmingen) and Yeast (Invitrogen) expression vectors containing His/fusion protein tags are also made in this way and the expression of recombinant protein is evaluated by SDS-PAGE and Western blot analysis.
Similar subcloning strategies are used with the desired TAT-001 nucleic acid sequences to produce other vectors, such as knock-out and knock-in vectors, expression vectors for mammalian cells, adenoviral vectors, vaccinia virus vectors, other tag or fusion vectors, and the like.
Three blocks of tissue from each matched normal and tumor specimen were kept for RNA extraction. Each block weighed approximately 50 mg, and was archived in RNAlater (Sigma-Aldrich; Product code R0901) at −80° C. (see Example 4). High quality RNA may later be obtained from most tissues using an RNeasy Mini Kit from QIAGEN (Valencia, Calif.). Each RNA preparation quality may be assessed by formaldehyde-agarose gel electrophoresis (see
The TAT-001 nucleic acid sequences may be confirmed by cloning from the colon tumor tissues used. This process may also identify polymorphisms, mutations, and/or variants including those particular to, or common to, the tumors used. One method that may be used for cloning TAT-001 nucleic acids is taken from the general cloning methodology used for cloning CD44 and CD98 from tumor cDNA. This method includes: 1) defming the start and stop sites of the target clone by RACE-PCR (Rapid Amplification of cDNA Ends—Polymerase Chain Reaction), preferably using the peptide sequence information obtained through the proteomics analysis for primer generation; 2) discovering variants by PCR walk from one end of the target to the other; and 3) assembly of full length clones by overlap PCR (see
In step 1 (see
In step 2 (see
In step 3, Overlap PCR, (see
Two case studies are provided that further exemplify the use of this method: CD98 and CD44. CD98 is a protein of 529 amino acids with a single transmembrane domain. Table 1 shows peptide information produced by mass spectrometry using the methods described in Example 4. Listed are the identified peptide sequences, their corresponding amino acid numbers in the overall CD98 sequence, and the gel bands they were identified in for each of 5 patients. The band locations suggested a single variant.
Primers were designed using 5 peptides (IGDLQAFQGHGAGNLAGLK (SEQ ID NO: 47), VILDLTPNYR (SEQ ID NO: 51), LLTSFLPAQLLR (SEQ ID NO: 52), GQSEDPGSLLSLFR (SEQ ID NO: 53) and ADLLLSTQPGREEGSPLELER (SEQ ID NO: 55)). Cloning of CD98 was done from cDNA of tumor RNA from a patient in which the peptides were identified. A single CD98 variant was detected and successfully cloned. Exemplary RACE-PCR reactions for CD98 are shown in
CD44 is a protein of 739 amino acids, with a single transmembrane domain. Not all the preferred requirements were met for this target. As for CD98, the peptides for CD44 are listed in Table 2. Some of the peptides are adjacent to one another in the CD44 sequence. The band locations suggested multiple variants. Up to 1092 possible variants have been predicted for CD44, though only a handful have been previously detected (Goodison S. et al. (1999) J Clin Pathol: Mol Pathol 52: 189). The mass spectrometry provided peptides did not distinguish between any of the variants.
Primers were designed using 3 peptides (LVINSGNGAVEDR (SEQ ID NO: 57), KPSGLNGEASK (SEQ ID NO: 58), and ESSETPDQFMTADETR (SEQ ID NO: 60)). Cloning of CD44 was initially done from cDNA of tumor RNA from 1 tumor, and was followed by cloning from two other tumors. Multiple CD44 variants were cloned and sequenced, see
A number of protocols may be used to purify TAT-001 polypeptides, such as immunoaffinity purification with available antibodies. Alternatively, tagged or fusion proteins such as those produced by vectors described in Example 6 may be expressed and purified with appropriate methodologies.
GST-TAT-001 fusion polypeptides, such as may be produced with the GST-fusion expression vector of Example 6 and
To remove the GST portion of the fusion protein, follow manufacturer instructions for pGEX-2T. Alternatively a GST-fusion may be designed that relies on other proteases, such as thrombin for cleavage.
His-tagged TAT-001 polypeptides may be expressed (see Example 6 for a potential vector description) in E. coli, and then extracted. Recombinant protein from a 250 ml cell pellet is extracted in 3 ml of extraction buffer by sonicating 6 times, with 6 second pulses at 4° C. The extract is then centrifuged at 15000×g for 10 minutes and the supernatant collected. The recombinant protein may be assayed for biological activity at this time.
The recombinant protein is purified by Ni—NTA affinity chromatography (Qiagen) according to the following protocol, performing all steps at 4° C. (refer to Qiagen protocols for more detail): use 3 ml Ni-beads (Qiagen), equilibrate column with equilibration buffer, load protein extract, wash with the equilibration buffer, elute bound protein with 0.5 M imidazole.
Recombinant TAT-001 proteins may also be purified using other routine protein purification methods, such as ammonium sulfate precipitation, affinity columns (e.g., immunoaffinity), size-exclusion, anion and cation exchange chromatography, gel electrophoresis and the like (see, generally, R. Scopes (1982) Protein Purification, Springer-Verlag, N.Y. and Deutscher (ed.) (1990) Methods in Enzymology Vol. 182: Guide to Protein Purification, Academic Press, Inc. N.Y.).
The purified TAT-001 polypeptides, and TAT-001 complexes provided by the present invention are, in one embodiment, highly purified (i.e., at least about 90% homogeneous, more often at least about 95% homogeneous). Homogeneity may be determined by standard means such as SDS-polyacrylamide gel electrophoresis and other means known in the art (see, e.g., Ausubel et al., supra). It will be understood that, although highly purified TAT-001 polypeptides, or TAT-001 complexes are sometimes desired, substantially purified (e.g., at least about 75% homogeneous) or partially purified (e.g., at least about 20% homogeneous) TAT-001 polypeptides, or TAT-001 complexes are useful in many applications, and are also provided by the present invention. For example, partially purified TAT-001 may be useful for screening test compounds for TAT-001 modulatory activity, and other uses.
Monoclonal antibodies in humanized or chimeric forms are useful for treating a variety of neoplastic diseases. TAT-001 antibodies are produced as follows. A TAT-001 polypeptide or modification thereof may be coupled to a carrier, such as keyhole limpet hemocyanin (KLH). Coupling of TAT-001 to KLH is performed as follows. 10 mg of the TAT-001 polypeptide is dissolved in 2 ml of phosphate buffered solution (PBS 1x). 1 ml of KLH (Pierce products #77100) is added to the peptide solution and stirred (1 mole of peptide/50 amino acids). The KLH concentration is 10 mg/ml. 20 μl of glutaraldehyde (25% aqueous solution) is added to the peptide/carrier solution with constant stirring, incubated for 1 hour, and then a glycine stop solution is added. The peptide/carrier conjugate is separated from the peptide by dialysis against PBS.
Polyclonal antibodies may be prepared according to standard methods, and an immune response enhanced with repeated booster injections, at intervals of 3 to 8 weeks. The success of the immunization may be verified by determining the concentration of antibodies in a western blot or ELISA or both. More specifically, to generate polyclonal antibodies to TAT-001, the TAT-001 polypeptide conjugated to KLH is injected into rabbits in accordance with an 164 day immunization regimen, after which the animals that produce specific antibodies are bled.
In order to sample the serum prior to immunization, 10 ml of blood per rabbit may be taken as a pre-immune control. TAT-001 polypeptides may also be used in competing peptide controls. Primary immunizations may be carried out with Freund's complete adjuvant and subsequent boosts with incomplete Freund's adjuvant (IFA) (1 ml per rabbit, 0.5 ml per thigh muscle). Each injection consists of approximately 200 μg of the purified peptide. At days 21, 42, and 70, a booster injection is given with IFA. At days 31, 42 and 80, 10 ml of blood is collected from the central ear artery for titer determination (6 ml/kg/rabbit). At day 80, the titer of the sera is checked, and 3 more injections are given (IFA) at 4 week intervals, followed by blood sampling 10 days later. 10 days after the last boost, anesthetized rabbits are exsanguinated via cardiac puncture, and antisera are collected.
Goat polyclonal antibodies can also be generated according to standard methods. Goats can be immunized as follows. On day 1, all goats receive a primary immunization of 1 mg of TAT-001 polypeptide-KLH conjugates in complete Freund's adjuvant. Boosts are done by injection of 1 mg TAT-001 polypeptide-KLH in incomplete Freund's adjuvant for the goats. Serum samples from bleeds are tested for reactivity by ELISA against TAT-001-BSA conjugates. From the third set of bleeds, total IgG can be purified by ammonium sulfate precipitation and TAT-001 polypeptide-reactive IgG can be purified using a TAT-001 polypeptide affinity column. IgG fractions are tested for reactivity to TAT-001 polypeptide as described herein. The exact immunization schedule was as follows: Day 1, primary immunization; Day 21, first boost immunization; Day 30, first bleed; Day 46, second boost immunization; Day 53, second boost immunization; Day 60, second bleed; Day 76, third boost immunization; Day 83, third boost immunization; and Day 90, third bleed.
Monoclonal antibodies may be prepared using TAT-001 polypeptides and standard hybridoma technology (see, e.g., Kohler et al. (1975) Nature 256: 495-497; Kohler et al. (1976) Eur J Immunol. 6: 511-519; Kohler et al. (1976) Eur J Immunol. 6: 292-295; Hammerling et aL (1981) in Monoclonal Antibodies and T Cell Hydridomas, Elsevier, NY; Ausubel et al. (1999) Current Protocols in Molecular Biology, Wiley Interscience, New York). Once produced, monoclonal antibodies are also tested for specific TAT-001 polypeptide recognition by immunoprecipitation and western blot analysis (e.g., by using the methods described in Ausubel et al., supra).
The generation of monoclonal antibodies can be carried out as follows. Mice are immunized initially with a TAT-001 polypeptide in complete Freund's adjuvant. All subsequent immunizations are made with a TAT-001 polypeptide in Freund's incomplete adjuvant or PBS (in a final volume of 0.5 ml; 1:1 with adjuvant) as a vehicle. The following booster immunizations are made at 2-6 week intervals: Boost 1, TAT-001 polypeptide; Boost 2, PBS and 50 μg of 8-map NQSLIPLLLEAR peptide (SEQ ID NO: 1) and 50 μg of 8-map FSQIELMLR peptide (SEQ ID NO: 3); Boost 3, purified TAT-001 (SEQ ID NO: 5) and 50 μg of 8-map NQSLIPLLLEAR peptide (SEQ ID NO: 1) and 50 μg of 8-map FSQIELMLR peptide (SEQ ID NO: 3); Boost 4, purified TAT-001 (SEQ ID NO: 5) and 100 μg CNQSLIPLLLEAR-KLH conjugate (SEQ ID NO: 62 and KLH conjugate) and 100 μg CFSQIELMLR-KLH conjugate (SEQ ID NO: 63 and KLH conjugate); Boost 5, purified TAT-001 and 50 μg CNQSLIPLLLEAR-KLH conjugate (SEQ ID NO: 62 and KLH conjugate) and 50 μg CFSQIELMLR-KLH conjugate (SEQ ID NO: 63 and KLH conjugate). Splenocytes from these mice are fused to the FO murine B cell line (ATCC CRL-1646) to generate specific hybridoma clones. Hybridoma supernantants are screened by ELISA.
Monoclonal antibodies can also be made in mice by genetic immunization. Plasmids containing a TAT-001 coding sequence, along with a restriction map, can be provided to Genovac (Aldevron LLC, Fargo, ND). Genovac subclones the TAT-001 or a portion thereof into their immunization vector, and mice are be immunized. Transfections of the same construct will are used to screen by flow cytometry the resulting hybridomas. Antibody reactivity can be confirmed by immunohistochemistry on cells transiently transfected or mock transfected cells with an expression vector containing TAT-001 coding sequence.
The antibodies of the invention may be selected by immobilizing a TAT-001 peptide and then panning a library of human antibody chains as described herein using the immobilized TAT-001 domain to bind antibody. The specificity and activity of specific clones can be assessed using assays known in the art. After a first panning step, a library of phage containing a plurality of different single chain antibodies displayed on phage having improved binding to the TAT-001 peptide is obtained. Subsequent panning steps provide additional libraries with higher binding affmities.
For recombinant production of the antibody, the nucleic acid encoding it may be isolated and inserted into a replicable vector for further cloning (amplification of the DNA) or for expression. DNA encoding the monoclonal antibody is isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of the antibody). Many vectors, as described herein, are available. The vector components generally include, but are not limited to, one or more of the following: a signal sequence, an origin of replication, one or more marker genes, an enhancer element, a promoter, and a transcription termination sequence.
Suitable host cells for cloning or expressing the DNA in the vectors herein are prokaryote, yeast, or higher eukaryote cells including animal and plant cell cultures. In general, host cells are transformed with the expression or cloning vectors for anti-TAT-001 antibody production and cultured in conventional nutrient media modified as appropriate for inducing promoters, selecting transformants, or amplifying the genes encoding the desired sequences. The antibody composition prepared from the cells can be purified according to standard methods well known in the art.
Amino acid sequence variants of the antibody are prepared by introducing appropriate nucleotide changes into the antibody DNA, or by peptide synthesis. Such variants include, for example, deletions from, and/or insertions into and/or substitutions of, residues within the amino acid sequences of the antibodies of the examples herein. Any combination of deletion, insertion, and substitution is made to arrive at the fmal construct, provided that the fmal construct possesses the desired binding characteristics. A useful method for identification of certain residues or regions of the antibody that are preferred locations for mutagenesis is called alanine scanning mutagenesis.
Total rabbit IgG can be purified from serum using a Pharmacia protein A HiTrap column according to the manufacturer's recommendations. Briefly, the HiTrap column is equilibrated with 3 column volumes of start buffer (0.2 M sodium phosphate buffer, pH 7.0). Serum is applied, using a syringe through a luer adaptor, onto the column. The column is subsequently washed with 5 ml of start buffer. Bound protein is eluted with 0.1 M glycine, pH 3.0, and collected in eppendorf tubes containing 1M Tris pH 8.0 (50 μl/500 μl sample). Fractions are analyzed on SDS-PAGE.
Goat polyclonal antibodies can be purified from serum samples as is described above.
Mouse monoclonal antibodies can be produced as ascites, and purified using a protein A column kit (Pierce) according to the manufacturer's instructions. Briefly, a sample of ascites is diluted with binding buffer at a 1:1 fmal ratio. The sample is then added to the top of the column, which has been previously equilibrated with binding buffer, and allowed to flow through the matrix. The pass-through material is collected and the column washed with 5 volumes of binding buffer. Mild elution buffer is added to the column to release the bound IgG antibody from the matrix. Other antibody isotypes are collected by switching to the IgG elution buffer. All the antibodies are collected in 1 ml fractions, which are analyzed by BCA to determine total protein content and SDS-PAGE electrophoresis to establish the degree of antibody purity. The fraction containing the most yield of IgG is desalted by passing it through a D-salt column (Pierce). The antibody fraction is allocated and stored at −80° C. in PBS.
Antigen-binding fragments of anti-TAT-001 antibodies, which may be produced by conventional techniques, are also encompassed by the present invention. Examples of such fragments include, but are not limited to, Fab and F(ab′)2 fragments. Antibody fragments and derivatives produced by genetic engineering techniques are also provided.
In one working example, pepsin digestion may be used to cleave the intact TAT-001 antibody into antibody fragments as follows. A buffer exchange with 11 mM sodium citrate (pH 3.5) using NAP™ −10 columns (Amersham Pharmacia Biotech) can be used. Pepsin digestion can also be done with an unrelated human antibody (for example, Chrompure IgM, Dianova, Hamburg, Germany) to obtain a suitable negative control. For each milligram of antibody, 5 μg pepsin (Sigma Aldrich, Taufkirchen, Germany) is added, followed by incubation for 10-15 minutes in a 37 ° C. water bath. The reaction is stopped by adding 1/10 volume of 3.0 M Tris (pH 8.8) followed by centrifuging at 10,000 g for 30 minutes. Prior to use in experiments, the fragmented TAT-001 antibody and the fragmented human control antibody can be dialyzed against PBS.
Following cleavage, the success of pepsin digestion may be analyzed by SDS-PAGE and Western blotting under non-reducing conditions. After blotting, the intact antibody may show the characteristic bands corresponding to intact antibody, monomeric forms, and light chains. By SDS-PAGE, the intact antibody may be unable to migrate into the stacking gel. However, following 10-15 minutes of treatment with pepsin, intact antibodies are completely digested into monomeric, F(ab)2, Fab, and light chain fragments which may be identified by molecular weight. The fragmented TAT-001 antibody may be tested for tumor-binding on paraffin sections of human colon carcinomas and compared to the intact TAT-001. Both antibody forms may possess similar binding patterns on tumor cells.
Cloning of the complementary-determining regions (CDRS) of anti-TAT-001 antibodies may be performed as follows. Total RNA from hybridomas which secrete a TAT-001-specific monoclonal antibody can be prepared according to a standard extraction procedure, and DNA fragments encoding the variable regions of the heavy and light chains can be amplified from poly(A)+RNA. The PCR products are then cloned into a vector such as pCR4-TOPO, pCR2.1-TOPO, or pBADThio-TOPO (Invitrogen) according to the manufacturer's instructions. The resulting clones are amplified in E. coli TOP10 cells (Invitrogen) with ampicillin (Roche) as a selective marker. Plasmid DNA is isolated from amplified clones using QIAGEN maxiprep kits, and nucleic acid sequencing is performed according to standard methods. Predicted amino acid sequences are then derived from the DNA sequences using Vector NTI (Informax).
On the basis of determining the predicted amino acid sequences, and according to the Chothia CDR definitions (Chothia et al. (1989) Nature 342: 877-83), CDRs of each variable region of mouse monoclonal antibodies to TAT-001 can be determined.
Several algorithms are available, such as the Dayhoff and Genetiq symbol comparison tables (Corpet (1988) Nucleic Acids Res. 16: 10881-10890), for aligning CDR3 sequences in order to derive a consensus sequence if multiple CDR sequences are available. These algorithms seek the minimum common elements in a collection of sequences. Immunizing antigens can be derived from determined CDR sequences and/or from deduced consensus sequences. Such sequences may also be used as antibody fragments, for example in TAT-001 binding assays, or as the basis for constrained peptides.
Humanization can be essentially performed for a non-human TAT-001 antibody following the method of Winter and co-workers (Jones et al. (1986) Nature 321: 522-525; Riechmann et al. (1988) Nature 332: 323-327; Verhoeyen et al. (1988) Science 239: 1534-1536), by substituting non-human TAT-001 antibody CDRs or CDR sequences for the corresponding sequences of a human antibody, or other methods referenced herein or known in the art. Accordingly, such “humanized” antibodies are chimeric antibodies wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.
To further characterize the cell surface expression of TAT-001, cell lines can be transfected with expression vectors containing fill-length TAT-001 as well as a negative control and stained with anti-TAT-001 antibodies post-transfection (generally about 24 to 72 hours later). Antibodies should be directed to an external portion of TAT-001, and a panel of peptide directed antibodies may be used to map external epitopes. Control antibodies, such as pre-immune serum for rabbit polyclonals, or antibody pre-incubated with antigen peptide to compete the specific binding. Surface expression can be visualized with the aid of microscopy, or analyzed by FACS. Tumor samples and normal tissues may also be stained to further confirm disease specific expression.
A determination of the distribution of TAT-001 in diseased and normal by tissue can be made by immunostaining of archived tissue sections, such as lung, colon, heart, liver and kidney, using anti-TAT-001 antibodies. Paraffm embedded formalin-fixed tissue can be sliced into 4 micron sections. Steam heat induced epitope retrieval (SHIER) in 0.1M sodium citrate buffer (pH 6.0) may be used for optimal staining conditions. Sections are incubated with 10% serum/PBS for 5 minutes. Primary antibody is added to each section for 25 minutes at varying concentrations, followed by a 25 minute incubation with a species-appropriate biotinylated secondary antibody. A negative control, such as pre-immune IgG in the case of rabbit antibodies should be used. Endogenous peroxidase activity is blocked by three 1.5 minute incubations with hydrogen peroxidase. The avidin biotin complex/horse radish peroxidase (ABC/HRP) system is used along with DAB chromogen to visualize antigen expression, and slides are counterstained with hematoxylin. SHIER and ABC/HRP may be used per Ventana Medical Systems, Tucson, Arizona.
A replacement-type targeting vector, which can be used to create a knockout model, can be constructed using an isogenic genomic clone, for example, from a mouse strain such as 129/Sv (Stratagene Inc., LaJolla, Calif.). Partial murine TAT-001 genomic sequence is provided (SEQ ID NO: 24) and remaining sequence can be determined using the methods of Example 5 and standard DNA sequencing methods. Partial genomic sequences are also provided for chimpanzee (SEQ ID NO: 31), rat (SEQ ID NO: 27), and chicken (SEQ ID NO: 34). The targeting vector can be introduced into a suitably-derived line of embryonic stem (ES) cells by electroporation to generate ES cell lines that carry a profoundly truncated form of a TAT-001 gene. To generate chimeric founder animals, for example, mice, the targeted cell lines are injected into a blastula-stage embryo. Heterozygous offspring can be interbred to homozygosity.
A patient diagnosed with a neoplasm (e.g., a colon carcinoma) may be treated with TAT-001 antibodies or fragments thereof as follows. Lugol's solution may be administered, e.g., 7 drops 3 times daily, to the patient. Subsequently, a therapeutic dose of 131I-TAT-001 antibody may be administered to the patient. For example, a 131I dose of 50 mCi may be given weekly for 3 weeks, and then repeated at intervals adjusted on an individual basis, e.g., every three months, until hematological toxicity interrupts the therapy. The exact treatment regimen is generally determined by the attending physician or person supervising the treatment. The radioiodinated antibodies may be administered as slow intravenous infusions in 50 ml of sterile physiological saline. After the third injection dose, a reduction in the size of the primary tumor and metastases may be noted, particularly after the second therapy cycle, or 10 weeks after onset of therapy.
In one working example, human administration of a TAT-001 polypeptide is performed as follows. A vaccine composed of 60 mg of a recombinant TAT-001 polypeptide in a total volume of 15 ml of water containing 2% w/v sucrose, pH 7.5 is orally administered to the patient. Administration of the vaccine is repeated at weekly intervals for a total of 4 doses. Symptoms are recorded daily by the patient. To determine adverse effects, physician interviews are performed weekly during the period of vaccine administration, as well as 1 week and 1 month after the last immunization. Anti-TAT-001 antibodies are measured in serum and saliva, and antibody-secreting cells are monitored in peripheral blood collected 7 days after the last immunization.
RT-PCR was performed on a panel of human tumor and normal cell lines. Tumor cell lines were derived from breast tumor, lung tumor, and colon tumors. G3PDH was used as a loading control. The results show increased expression levels of TAT-001 MRNA in several tumor cell lines (
It will be clear that the invention may be practiced other than as particularly described in the foregoing description and examples. Numerous modifications and variations of the present invention are possible in light of the above teachings and, therefore, are within the scope of the claims.
Preferred features of each aspect of the invention are as for each of the other aspects mutatis mutandis. The documents including patents, patent applications, journal articles, abstracts, laboratory manuals, books, or other disclosures mentioned herein are hereby incorporated to the fullest extent permitted by law. Further, the hard copy of the sequence listing submitted herewith and the corresponding computer readable form are both incorporated herein by reference in their entireties.
This application claims priority from U.S. provisional patent application 60/648,758, filed Jan. 31, 2005, hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60648758 | Jan 2005 | US |
