Patent Application
20060094061
The present invention relates to methods for identifying compounds, and expression-inhibition agents, capable of inhibiting the expression of proteins involved in the pathway resulting in the degradation of extra-cellular matrix (ECM), which inhibition is useful in the prevention and treatment of joint degeneration and diseases involving such degradation and/or inflammation.
Diseases involving the degradation of extra-cellular matrix include, but are not limited to, psoriatic arthritis, juvenile arthritis, early arthritis, reactive arthritis, osteoarthritis, ankylosing spondylitis. osteoporosis, muscular skeletal diseases like tendonitis and periodontal disease, cancer metastasis, airway diseases (COPD, asthma), renal and liver fibrosis, cardio-vascular diseases like atherosclerosis and heart failure, and neurological diseases like neuroinflammation and multiple sclerosis. Diseases involving primarily joint degeneration include, but are not limited to, psoriatic arthritis, juvenile arthritis, early arthritis, reactive arthritis, osteoarthritis, ankylosing spondylitis.
Rheumatoid arthritis (RA) is a chronic joint degenerative disease, characterized by inflammation and destruction of the joint structures. When the disease is unchecked, it leads to substantial disability and pain due to loss of joint functionality and even premature death. The aim of an RA therapy, therefore, is not to slow down the disease but to attain remission in order to stop the joint destruction. Besides the severity of the disease outcome, the high prevalence of RA (˜0.8% of the adults are affected worldwide) means a high socio-economic impact. (For reviews on RA, we refer to Smolen and Steiner (2003); Lee and Weinblatt (2001); Choy and Panayi (2001); O'Dell (2004) and Firestein (2003)).
Although it is widely accepted that RA is an auto-immune disease, there is no consensus concerning the precise mechanisms driving the ‘initiation stage’ of the disease. What is known is that the initial trigger(s) does mediate, in a predisposed host, a cascade of events that leads to the activation of various cell types (B-cells, T-cells, macrophages, fibroblasts, endothelial cells, dendritic cells and others). Concomitantly, an increased production of various cytokines is observed in the joints and tissues surrounding the joint (for example, TNF-α, IL-6, IL-1, IL-15, IL-18 and others). As the disease progresses, the cellular activation and cytokine production cascade becomes self-perpetuating. At this early stage, the destruction of joint structures is already very clear. Thirty percent of the patients have radiographic evidence of bony erosions at the time of diagnosis and this proportion increases to 60 percent after two years.
Histologic analysis of the joints of RA patients clearly evidences the mechanisms involved in the RA-associated degradative processes. The synovium is a cell layer, composed of a sublining and a lining region that separates the joint capsule from the synovial cavity. The inflamed synovium is central to the pathophysiology of RA. The synovial joint is shown as composed of two adjacent bony ends each covered with a layer of cartilage, separated by a joint space and surrounded by the synovial membrane and joint capsule. The synovial membrane is composed of the synovial lining (facing the cartilage and bone), which consists of a thin (1-3 cells) layer of synoviocytes and the sublining connective tissue layer that is highly vascularised. The synovial membrane covers almost all intra-articular structures except for cartilage. Histological differences in the synovium between normal and RA patients are indicated in
Like many other forms of arthritis, rheumatoid arthritis (RA) is initially characterized by an inflammatory response of the synovial membrane (‘synovitis’) that is characterised by an important influx of various types of mononuclear cells as well as by the activation of the local or infiltrated mononuclear cells. The lining layer becomes hyperplastic (it can have a thickness of >20 cells) and the synovial membrane expands. However, in addition, the hallmark of RA is joint destruction: the joint spaces narrow or disappear as a sign of cartilage degradation and destructions of the adjacent bone, also termed ‘erosions’, have occurred. The destructive portion of the synovial membrane is termed ‘pannus’. Enzymes secreted by synoviocytes lead to cartilage degradation.
This analysis shows that the main effector responsible for RA-associated joint degradation is the pannus, where the synovial fibroblast, by producing diverse proteolytic enzymes, is the prime driver of cartilage and bone erosion. In the advanced RA patient, the pannus mediates the degradation of the adjacent cartilage, leading to the narrowing of the joint space, and has the potential to invade adjacent bone and cartilage. As collagen type I or II are main components of bone and cartilage tissues, respectively, the pannus destructive and invasive properties are mediated by the secretion of collagenolytic proteases, principally the matrix metallo proteinases (MMPs). The erosion of the bone under and adjacent to the cartilage is also part of the RA process, and results principally from the presence of osteoclasts at the interface of bone and pannus. Osteoclasts adhere to the bone tissue and form a closed compartment, within which the osteoclasts secrete proteases (Cathepsin K, MMP9) that degrade the bone tissue. The osteoclast population in the joint is abnormally increased by osteoblast formation from precursor cells induced by the secretion of the receptor activator of NFkB ligand (RANKL) by activated SFs and T-cells.
Various collagen types have a key role in defining the stability of the extra-cellular matrix (ECM). Collagen type I and collagen type II, for example, are main components of bone and cartilage, respectively. Collagen proteins typically organize into multimeric structures referred to as collagen fibrils. Native collagen fibrils are very resistant to proteolytic cleavage. Only a few types of ECM-degrading proteins have been reported to have the capacity to degrade native collagen: matrix-metallo proteases (MMPs) and Cathepsins. Among the Cathepsins, cathepsin K, which is active mainly in osteoclasts, is the best characterised.
Matrix Metallo Proteases (MMPs) possess various physiological roles, for example, they are involved in the maturation of other proteases, growth factors, and the degradation of extra-cellular matrix components. Among the MMPs, MMP1, MMP2, MMP8 MMP13 and MMP14 are known to have collagenolytic properties. MMP1 is a member of the MMP family and is able to degrade native collagen, an important component of bone and cartilage. The correlation between an increased expression of MMP1 by synovial fibroblasts (SFs) and the progression of the arthritic disease is well-established and is predictive for joint erosive processes (Cunnane et al., 2001). In the context of RA, therefore, MMP1 represents a highly relevant collagen degrading protein. In vitro, the treatment of cultured SFs with cytokines relevant in the RA pathology (for example, TNF-α and IL1β) will increase the expression of MMP1 by these cells (Andreakos et al., 2003).
The activity of the ECM-degrading proteins can also be causative or correlate with the progression of various diseases other than RA, which diseases involve also the degradation of the joints. These diseases include, but are not limited to, psoriatic arthritis, juvenile arthritis, early arthritis, reactive arthritis, osteoarthritis, and ankylosing spondylitis. Other diseases that may be treatable with compounds identified according to the present invention and using the targets involved in the expression of MMPs as described herein are osteoporosis, muscular skeletal diseases like tendonitis and periodontal disease (Gapski et al., 2004), cancer metastasis (Coussens et al., 2002), airway diseases (COPD, asthma) (Suzuki et al., 2004), lung, renal fibrosis (Schanstra et al., 2002), liver fibrosis associated with chronic hepatitis C (Reiff et al., 2005), cardio-vascular diseases like atherosclerosis and heart failure (Creemers et al., 2001), and neurological diseases like neuro-inflammation and multiple sclerosis (Rosenberg, 2002). Patients suffering from such diseases may benefit from a therapy that protects the ECM from enzymatic degradation.
NSAIDS (Non-steroidal anti-inflammatory drugs) are used to reduce the pain associated with RA and improve life quality of the patients. These drugs will not, however, put a brake on the RA-associated joint destruction.
Corticosteroids are found to decrease the progression of RA as detected radiographically and are used at low doses to treat part of the RA patients (30 to 60%). Serious side effects, however, are associated with long corticosteroid use (Skin thinning, osteoporosis, cataracts, hypertension, hyperlipidemia).
Synthetic DMARDs (Disease-Modifying Anti-Rheumatic Drugs) (for example, methotrexate, leflunomide, sulfasalazine) mainly tackle the immuno-inflammatory component of RA. As a main disadvantage, these drugs only have a limited efficacy (joint destruction is only slowed down but not blocked by DMARDs such that disease progression in the long term continues). The lack of efficacy is indicated by the fact that, on average, only 30% of the patients achieve an ACR50 score after 24 months treatment with methotrexate. This means that, according to the American College of Rheumatology, only 30% of the patients do achieve a 50% improvement of their symptoms (O'Dell et al., 1996). In addition, the precise mechanism of action of DMARDs is often unclear.
Biological DMARDs (Infliximab, Etanercept, Adalimumab, Rituximab, CTLA4-Ig) are therapeutic proteins that inactivate cytokines (for example, TNF-α) or cells (for example, T-cells or B-cells) that have an important role in the RA pathophysiology (Kremer et al., 2003; Edwards et al., 2004). Although the TNF-α-blockers (Infliximab, Etanercept, Adalimumab) and methotrexate combination therapy is the most effective RA treatment currently available, it is striking that even this therapy only achieves a 50% improvement (ACR50) in disease symptoms in 50-60% of patients after 12 months therapy (St Clair et al., 2004). Some adverse events warnings for anti-TNF-α drugs exist, shedding a light on the side effects associated to this type of drugs. Increased risk for infections (tuberculosis) hematologic events and demyelinating disorders have been described for the TNF-α blockers. (see also Gomez-Reino et al., 2003). Besides the serious side effects, the TNF-α blockers do also share the general disadvantages of the biological class of therapeutics, which are the unpleasant way of administration (frequent injections accompanied by infusion site reactions) and the high production cost. Newer agents in late development phase target T-cell co-stimulatory molecules and B-cells. The efficacy of these agents is expected to be similar to that of the TNF-α blockers. The fact that a variety of targeted therapies have similar but limited efficacies, suggests that there is a multiplicity of pathogenic factors for RA. This is also indicative for the deficiencies in our understanding of pathogenic events relevant to RA.
The current therapies for RA are not satisfactory due to a limited efficacy (no adequate therapy exists for 30% of the patients). This calls for additional strategies to achieve remission. Remission is required since residual disease bears the risk of progressive joint damage and thus progressive disability. Inhibiting the immuno-inflammatory component of the RA disease, which represents the main target of drugs currently used for RA treatment, does not result in a blockade of joint degradation, the major hallmark of the disease.
The histological analysis of RA patient joints clearly identifies the pannus, as an aggressive, invasive tissue that represents the main culprit in joint degradation. Within the pannus, the synovial fibroblasts represent a link between the initiation of the abnormally triggered immune system that lies at the basis of RA pathogenesis, and the ultimate joint erosion. As no current RA therapy efficiently abolishes the erosive activity of the pannus in the long term, the discovery of novel drugs and/or drug targets that inhibit the generation, and/or the activity, of the pannus would represent an important milestone for the development of novel RA treatments.
The present invention is based on the discovery of that certain proteins function in the pathway that results in the expression of extra-cellular matrix (ECM) degradation proteases, such as MMP1, and that inhibitors of the activity of these proteins, are useful for the treatment of diseases involving the abnormally high expression of such proteases.
The present invention relates to a method for identifying compounds that inhibit extra-cellular matrix (ECM) degradation, comprising contacting a compound with a polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 17-32 (hereinafter “TARGETS”) and fragments thereof, under conditions that allow said polypeptide to bind to said compound, and measuring a compound-polypeptide property related to extra-cellular matrix (ECM) degradation.
Aspects of the present method include the in vitro assay of compounds using polypeptide of a TARGET, or fragments thereof, such fragments including the amino acid sequences described by SEQ ID NO: 33-127, and cellular assays wherein TARGET inhibition is followed by observing indicators of efficacy including, for example, TARGET expression levels, TARGET enzymatic activity and/or Matrix Metallo Proteinase-1 levels.
The present invention also relates to (1) expression inhibitory agents comprising a polynucleotide selected from the group of an antisense polynucleotide, a ribozyme, and a small interfering RNA (siRNA), wherein said polynucleotide comprises a nucleic acid sequence complementary to, or engineered from, a naturally occurring polynucleotide sequence encoding a polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 17-127, and (2) pharmaceutical compositions comprising said agent, useful in the treatment, or prevention, of chronic joint degenerative diseases such as rheumatoid arthritis.
Another aspect of the invention is a method of treatment, or prevention, of a condition involving extra-cellular matrix (ECM) degradation, in a subject suffering or susceptible thereto, by administering a pharmaceutical composition comprising an effective TARGET-expression inhibiting amount of a expression-inhibitory agent or an effective TARGET activity inhibiting amount of a activity-inhibitory agent.
A further aspect of the present invention is a method for diagnosis relating to disease conditions characterized by extra-cellular matrix (ECM) degradation comprising measurement of indicators of levels of TARGET expression in a subject.
Another aspect of this invention relates to the use of the present compound in a therapeutic method, a pharmaceutical composition, and the manufacture of such composition, useful for the treatment of a disease involving inflammation, and in particular, a disease characteristic of abnormal matrix metallo protease activity.
The following terms are intended to have the meanings presented therewith below and are useful in understanding the description and intended scope of the present invention.
The term “agent” means any molecule, including polypeptides, polynucleotides and small molecules.
The term “agonist” refers to a ligand that stimulates the receptor the ligand binds to in the broadest sense.
The term “assay” means any process used to measure a specific property of a compound. A “screening assay” means a process used to characterize or select compounds based upon their activity from a collection of compounds.
The term “binding affinity” is a property that describes how strongly two or more compounds associate with each other in a non-covalent relationship. Binding affinities can be characterized qualitatively, (such as “strong”, “weak”, “high”, or “low”) or quantitatively (such as measuring the KD).
The term “carrier” means a non-toxic material used in the formulation of pharmaceutical compositions to provide a medium, bulk and/or useable form to a pharmaceutical composition. A carrier may comprise one or more of such materials such as an excipient, stabilizer, or an aqueous pH buffered solution. Examples of physiologically acceptable carriers include aqueous or solid buffer ingredients including phosphate, citrate, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptide; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic surfactants such as TWEEN™, polyethylene glycol (PEG), and PLURONICS™.
The term “complex” means the entity created when two or more compounds bind to each other.
The term “compound” is used herein in the context of a “test compound” or a “drug candidate compound” described in connection with the assays of the present invention. As such, these compounds comprise organic or inorganic compounds, derived synthetically or from natural sources. The compounds include inorganic or organic compounds such as polynucleotides, lipids or hormone analogs that are characterized by relatively low molecular weights. Other biopolymeric organic test compounds include peptides comprising from about 2 to about 40 amino acids and larger polypeptides comprising from about 40 to about 500 amino acids, such as antibodies or antibody conjugates.
The term “condition” or “disease” means the overt presentation of symptoms (i.e., illness) or the manifestation of abnormal clinical indicators (for example, biochemical indicators). Alternatively, the term “disease” refers to a genetic or environmental risk of or propensity for developing such symptoms or abnormal clinical indicators.
The term “contact” or “contacting” means bringing at least two moieties together, whether in an in vitro system or an in vivo system.
The term “derivatives of a polypeptide” relates to those peptides, oligopeptides, polypeptides, proteins and enzymes that comprise a stretch of contiguous amino acid residues of the polypeptide and that retain the biological activity of the protein, for example, polypeptides that have amino acid mutations compared to the amino acid sequence of a naturally-occurring form of the polypeptide. A derivative may further comprise additional naturally occurring, altered, glycosylated, acylated or non-naturally occurring amino acid residues compared to the amino acid sequence of a naturally occurring form of the polypeptide. It may also contain one or more non-amino acid substituents compared to the amino acid sequence of a naturally occurring form of the polypeptide, for example a reporter molecule or other ligand, covalently or non-covalently bound to the amino acid sequence.
The term “derivatives of a polynucleotide” relates to DNA-molecules, RNA-molecules, and oligonucleotides that comprise a stretch or nucleic acid residues of the polynucleotide, for example, polynucleotides that may have nucleic acid mutations as compared to the nucleic acid sequence of a naturally occurring form of the polynucleotide. A derivative may further comprise nucleic acids with modified backbones such as PNA, polysiloxane, and 2′-O-(2-methoxy) ethyl-phosphorothioate, non-naturally occurring nucleic acid residues, or one or more nuclei acid substituents, such as methyl-, thio-, sulphate, benzoyl-, phenyl-, amino-, propyl-, chloro-, and methanocarbanucleosides, or a reporter molecule to facilitate its detection.
The terms “ECM-degrading protein” and “ECM-degrading activity” refer to a protein and activity, respectively, which are capable of degrading extra-cellular matrixes found in bone and cartilage.
The term “effective amount” or “therapeutically effective amount” means that amount of a compound or agent that will elicit the biological or medical response of a subject that is being sought by a medical doctor or other clinician.
The term “endogenous” shall mean a material that a mammal naturally produces. Endogenous in reference to the term “protease”, “kinase”, or G-Protein Coupled Receptor (“GPCR”) shall mean that which is naturally produced by a mammal (for example, and not limitation, a human). In contrast, the term non-endogenous in this context shall mean that which is not naturally produced by a mammal (for example, and not limitation, a human). Both terms can be utilized to describe both “in vivo” and “in vitro” systems. For example, and not a limitation, in a screening approach, the endogenous or non-endogenous TARGET may be in reference to an in vitro screening system. As a further example and not limitation, where the genome of a mammal has been manipulated to include a non-endogenous TARGET, screening of a candidate compound by means of an in vivo system is viable.
The term “expressible nucleic acid” means a nucleic acid coding for a proteinaceous molecule, an RNA molecule, or a DNA molecule.
The term “expression” comprises both endogenous expression and overexpression by transduction.
The term “expression inhibitory agent” means a polynucleotide designed to interfere selectively with the transcription, translation and/or expression of a specific polypeptide or protein normally expressed within a cell. More particularly, “expression inhibitory agent” comprises a DNA or RNA molecule that contains a nucleotide sequence identical to or complementary to at least about 17 sequential nucleotides within the polyribonucleotide sequence coding for a specific polypeptide or protein. Exemplary expression inhibitory molecules include ribozymes, double stranded siRNA molecules, self-complementary single-stranded siRNA molecules, genetic antisense constructs, and synthetic RNA antisense molecules with modified stabilized backbones.
The term “expressible nucleic acid” means a nucleic acid coding for a proteinaceous molecule, an RNA molecule, or a DNA molecule.
The term “fragment of a polynucleotide” relates to oligonucleotides that comprise a stretch of contiguous nucleic acid residues that exhibit substantially a similar, but not necessarily identical, activity as the complete sequence.
The term “fragment of a polypeptide” relates to peptides, oligopeptides, polypeptides, proteins and enzymes that comprise a stretch of contiguous amino acid residues, and exhibit substantially a similar, but not necessarily identical, functional activity as the complete sequence.
The term “hybridization” means any process by which a strand of nucleic acid binds with a complementary strand through base pairing. The term “hybridization complex” refers to a complex formed between two nucleic acid sequences by virtue of the formation of hydrogen bonds between complementary bases. A hybridization complex may be formed in solution (for example, C0t or R0t analysis) or formed between one nucleic acid sequence present in solution and another nucleic acid sequence immobilized on a solid support (for example, paper, membranes, filters, chips, pins or glass slides, or any other appropriate substrate to which cells or their nucleic acids have been fixed). The term “stringent conditions” refers to conditions that permit hybridization between polynucleotides and the claimed polynucleotides. Stringent conditions can be defined by salt concentration, the concentration of organic solvent, for example, formamide, temperature, and other conditions well known in the art. In particular, reducing the concentration of salt, increasing the concentration of formamide, or raising the hybridization temperature can increase stringency.
The term “inhibit” or “inhibiting”, in relationship to the term “response” means that a response is decreased or prevented in the presence of a compound as opposed to in the absence of the compound.
The term “inhibition” refers to the reduction, down regulation of a process or the elimination of a stimulus for a process that results in the absence or minimization of the expression of a protein or polypeptide.
The term “induction” refers to the inducing, up-regulation, or stimulation of a process that results in the expression of a protein or polypeptide.
The term “ligand” means an endogenous, naturally occurring molecule specific for an endogenous, naturally occurring receptor.
The term “pharmaceutically acceptable salts” refers to the non-toxic, inorganic and organic acid addition salts, and base addition salts, of compounds of the present invention. These salts can be prepared in situ during the final isolation and purification of compounds useful in the present invention.
The term “polypeptide” relates to proteins, proteinaceous molecules, fractions of proteins, peptides, oligopeptides, enzymes (such as kinases, proteases, GCPR's etc.).
The term “polynucleotide” means a polynucleic acid, in single or double stranded form, and in the sense or antisense orientation, complementary polynucleic acids that hybridize to a particular polynucleic acid under stringent conditions, and polynucleotides that are homologous in at least about 60 percent of its base pairs, and more preferably 70 percent of its base pairs are in common, most preferably 90 percent, and in a special embodiment 100 percent of its base pairs. The polynucleotides include polyribonucleic acids, polydeoxyribonucleic acids, and synthetic analogues thereof. It also includes nucleic acids with modified backbones such as peptide nucleic acid (PNA), polysiloxane, and 2′-O-(2-methoxy)ethylphosphorothioate. The polynucleotides are described by sequences that vary in length, that range from about 10 to about 5000 bases, preferably about 100 to about 4000 bases, more preferably about 250 to about 2500 bases. One polynucleotide embodiment comprises from about 10 to about 30 bases in length. A special embodiment of polynucleotide is the polyribonucleotide of from about 17 to about 22 nucleotides, more commonly described as small interfering RNAs (siRNAs). Another special embodiment are nucleic acids with modified backbones such as peptide nucleic acid (PNA), polysiloxane, and 2′-O-(2-methoxy)ethylphosphorothioate, or including non-naturally occurring nucleic acid residues, or one or more nucleic acid substituents, such as methyl-, thio-, sulphate, benzoyl-, phenyl-, amino-, propyl-, chloro-, and methanocarbanucleosides, or a reporter molecule to facilitate its detection.
The term “polypeptide” relates to proteins (such as TARGETS), proteinaceous molecules, fractions of proteins peptides and oligopeptides.
The term “solvate” means a physical association of a compound useful in this invention with one or more solvent molecules. This physical association includes hydrogen bonding. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of the crystalline solid. “Solvate” encompasses both solution-phase and isolable solvates. Representative solvates include hydrates, ethanolates and methanolates.
The term “subject” includes humans and other mammals.
The term “TARGET” or “TARGETS” means the protein(s) identified in accordance with the assays described herein and determined to be involved in the modulation of MMP1 expression levels.
“Therapeutically effective amount” means that amount of a drug or pharmaceutical agent that will elicit the biological or medical response of a subject that is being sought by a medical doctor or other clinician. In particular, with regard to treating an disease condition characterized by the degradation of extracellular matrix, the term “effective matrix metallo-protease inhibiting amount” is intended to mean that effective amount of an compound of the present invention that will bring about a biologically meaningful decrease in the production of MMP-1 in the subject's disease affected tissues such that extracellular matrix degradation is meaningfully reduced. A compound having matrix metallo-protease inhibiting properties or a “matrix metallo-protease inhibiting compound” means a compound that provided to a cell in effective amounts is able to cause a biologically meaningful decrease in the production of MMP-1 in such cells.
The term “treating” means an intervention performed with the intention of preventing the development or altering the pathology of, and thereby alleviating a disorder, disease or condition, including one or more symptoms of such disorder or condition. Accordingly, “treating” refers to both therapeutic treatment and prophylactic or preventative measures. Those in need of treating include those already with the disorder as well as those in which the disorder is to be prevented. The related term “treatment,” as used herein, refers to the act of treating a disorder, symptom, disease or condition, as the term “treating” is defined above.
Applicants' Invention Based on TARGET Relationship to Extra-cellular Matrix Degradation
MMP1 expression by SFs is relevant to ECM degradation as it correlates to the activation of SFs towards an erosive phenotype that, in vivo, is responsible for cartilage degradation. This has been demonstrated by the administration to TNFα transgenic mice, which spontaneously develop an arthritic phenotype, of adenovirus that overexpress TIMP1, an inhibitor of MMPs, which administration results in the reduction of joint degradation (Shett et al., Arthritis Rheum. (2001) 44:2888-98). Therefore, inhibition of the MMP1 expression by SFs represents a valuable therapeutic approach towards the treatment of RA. Accordingly, if the reduction in expression of a candidate protein in activated SFs leads to a corresponding reduction of MMP1 expression, then such protein is involved in the regulation of MMP1 expression and is a relevant target for the development of therapeutic strategies for the treatment of RA. The present inventors have identified such target proteins by screening recombinant adenoviruses mediating the expression of a library of shRNAs, referred to herein as “Ad-siRNAs.” The collection used herein is further referred to as “adenoviral siRNA library” or “SilenceSelect” collection. These libraries contain recombinant adenoviruses, further referred to as knock-down (KD) viruses or Ad-siRNAs, that mediate the expression in cells of shRNAs which reduce the expression levels of targeted genes by a RNA interference (RNAi)-based mechanism (WO03/020931). The screening work is described below in Example 1.
As noted above, the present invention is based on the present inventors' discovery that the TARGET polypeptides, identified as a result of a variety of screens described below in the Examples, are factors not only in the up-regulation and/or induction of MMP1, but even in the up-regulation and/or induction of extra-cellular matrix degradation. The activity of the ECM-degrading proteins is believed to be causative and to correlate with the progression of various diseases associated with an increased degradation of the extra-cellular matrix, including diseases that involve the degradation of the joint.
In one aspect, the present invention relates to a method for assaying for drug candidate compounds that inhibit extra-cellular matrix degradation, comprising contacting the compound with a polypeptide comprising an amino acid sequence of SEQ ID NO: 17-127, or fragment thereof, under conditions that allow said polypeptide to bind to the compound, and detecting the formation of a complex between the polypeptide and the compound. One preferred means of measuring the complex formation is to determine the binding affinity of said compound to said polypeptide.
More particularly, the invention relates to a method for identifying an agent that inhibits extra-cellular matrix degradation, the method comprising further:
The compound-polypeptide property referred to above is related to the expression and/or activity of the TARGET, and is a measurable phenomenon chosen by the person of ordinary skill in the art. The measurable property may be, for example, the binding affinity for a peptide domain of the polypeptide TARGET such as for SEQ ID NO: 33-127, or the level of any one of a number of biochemical marker levels of extra-cellular matrix degradation. Extra-cellular matrix degradation can be measured, for example, by measuring the level of enzymes that are induced during the process, such as expression of a MMP and/or a Cathepsin polypeptide.
In a preferred embodiment of the invention, the TARGET polypeptide comprises an amino acid sequence selected from the group consisting of SEQ ID No: 17-32 as listed in Table 1.
Another special embodiment of the invention comprises the kinase TARGETS identified as SEQ ID NOS. 19-22, 25, 26, 29, 30, and 32. Another special embodiment of the invention comprises the ion channel TARGETS identified as SEQ ID NOS. 17, 18, 24, and 27. A further preferred embodiment is the Nuclear Hormone Receptors (NHRs) TARGET identified as SEQ. ID NO. 23.
Depending on the choice of the skilled artisan, the present assay method may be designed to function as a series of measurements, each of which is designed to determine whether the drug candidate compound is indeed acting on the polypeptide to thereby inhibit extra-cellular matrix degradation. For example, an assay designed to determine the binding affinity of a compound to the polypeptide, or fragment thereof, may be necessary, but not sufficient, to ascertain whether the test compound would be useful for inhibiting extra-cellular matrix degradation when administered to a subject.
Such binding information would be useful in identifying a set of test compounds for use in an assay that would measure a different property, further down the biochemical pathway, such as for example MMP-1 expression. Such second assay may be designed to confirm that the test compound, having binding affinity for the polypeptide, actually inhibits extra-cellular matrix degradation. Suitable controls should always be in place to insure against false positive readings.
The order of taking these measurements is not believed to be critical to the practice of the present invention, which may be practiced in any order. For example, one may first perform a screening assay of a set of compounds for which no information is known respecting the compounds' binding affinity for the polypeptide. Alternatively, one may screen a set of compounds identified as having binding affinity for a polypeptide domain, or a class of compounds identified as being an inhibitor of the polypeptide. However, for the present assay to be meaningful to the ultimate use of the drug candidate compounds, a measurement of extra-cellular matrix degradation activity is necessary. Validation studies including controls and measurements of binding affinity to the polypeptides of the invention are nonetheless useful in identifying a compound useful in any therapeutic or diagnostic application. The present assay method may be practiced in vitro, using one or more of the TARGET proteins, or fragments thereof. The amino acid sequences of exemplary protein domain fragments of selected TARGETS are SEQ ID NO: 33-127, listed in Table 1A below.
The binding affinity of a compound with the polypeptide TARGET can be measured by methods known in the art, such as using surface plasmon resonance biosensors (Biacore), by saturation binding analysis with a labeled compound (for example, Scatchard and Lindmo analysis), by differential UV spectrophotometer, fluorescence polarization assay, Fluorometric Imaging Plate Reader (FLIPR®) system, Fluorescence resonance energy transfer, and Bioluminescence resonance energy transfer. The binding affinity of compounds can also be expressed in dissociation constant (Kd) or as IC50 or EC50. The IC50 represents the concentration of a compound that is required for 50% inhibition of binding of another ligand to the polypeptide. The EC50 represents the concentration required for obtaining 50% of the maximum effect in any assay that measures TARGET function. The dissociation constant, Kd, is a measure of how well a ligand binds to the polypeptide, it is equivalent to the ligand concentration required to saturate exactly half of the binding-sites on the polypeptide. Compounds with a high affinity binding have low Kd, IC50 and EC50 values, for example, in the range of 100 nM to 1 pM; a moderate- to low-affinity binding relates to high Kd, IC50 and EC50 values, for example in the micromolar range.
The present assay method may also be practiced in a cellular assay, A host cell expressing the TARGET can be a cell with endogenous expression or a cell over-expressing the TARGET, for example, by transduction. When the endogenous expression of the polypeptide is not sufficient to determine a baseline that can easily be measured, one may use using host cells that over-express TARGET. Over-expression has the advantage that the level of the TARGET substrate end-products is higher than the activity level by endogenous expression. Accordingly, measuring such levels using presently available techniques is easier.
One embodiment of the present method for identifying a compound that decreases extra-cellular matrix (ECM) degradation comprises culturing a population of mammalian cells expressing a TARGET polypeptide, or a functional fragment or derivative thereof; determining a first level of ECM degradation in said population of cells; eventually activating the population of cells; exposing said population of cells to a compound, or a mixture of compounds; determining a second level of ECM degradation in said population of cells during or after exposure of said population of cells to said compound, or the mixture of said compounds; and identifying the compound(s) that decreases ECM degradation. As noted above, ECM degradation may be determined by measuring the expression and/or activity of the TARGET polypeptide and/or a known ECM-degrading protein. In a preferred embodiment, said ECM-degrading protein is able to degrade collagen, and more preferably, is able to degrade collagen type I and/or collagen type II. In another preferred embodiment of the present invention, said ECM-degrading protein is a Matrix Metallo Proteinase (MMP), and more preferably is selected from the group consisting of MMP1, MMP2, MMP3, MMP8, MMP9, MMP13 and MMP14. In this context, the most preferred ECM-degrading protein is Matrix Metalloprotease 1 (MMP1). In yet another preferred embodiment, said ECM-degrading protein is Cathepsin K.
The expression of an ECM-degrading protein can be determined by methods known in the art such as Western blotting using specific antibodies, or an ELISA using antibodies specifically recognizing a particular ECM-degrading protein.
The activity of an ECM-degrading protein can be determined by using fluorogenic small peptide substrates. The specificity of these substrates, however, is often limited. In general, the use of these substrates is limited to the testing of purified proteases in biochemical assays, to avoid interference of other proteases.
The present inventors have developed a protocol allowing the detection, in a high throughput mode, of the activity of collagen degrading enzymes in complex media such as the supernatant of cultured cells. This protocol makes use of native collagen, being labelled with a fluorescent label, as a substrate.
The present inventors identified TARGET genes involved in ECM-degradation by using a ‘knock-down’ library. This type of library is a screen in which siRNA molecules are transduced into cells by recombinant adenoviruses, which siRNA molecules inhibit or repress the expression of a specific gene as well as expression and activity of the corresponding gene product in a cell. Each siRNA in a viral vector corresponds to a specific natural gene. By identifying a siRNA that represses ECM-degradation, a direct correlation can be drawn between the specific gene expression and ECM degradation. The TARGET genes identified using the knock-down library (the protein expression products thereof herein referred to as “TARGET” polypeptides) are then used in the present inventive method for identifying compounds that can be used to prevent ECM-degradation. Indeed, shRNA compounds comprising the sequences listed in Table 2 (SEQ ID NO: 128-141 and 231-244) inhibit the expression and/or activity of these TARGET genes and decrease the ECM-degrading activity of cells, confirming the role of the TARGETS in ECM-degradation.
Specific methods to determine the activity of a kinase by measuring the phosphorylation of a substrate by the kinase, which measurements are performed in the presence or absence of a compound, are well known in the art.
Ion channels are membrane protein complexes and their function is to facilitate the diffusion of ions across biological membranes. Membranes, or phospholipid bilayers, build a hydrophobic, low dielectric barrier to hydrophilic and charged molecules. Ion channels provide a high conducting, hydrophilic pathway across the hydrophobic interior of the membrane. The activity of an ion channel can be measured using classical patch clamping. High-throughput fluorescence-based or tracer-based assays are also widely available to measure ion channel activity. These fluorescent-based assays screen compounds on the basis of their ability to either open or close an ion channel thereby changing the concentration of specific fluorescent dyes across a membrane. In the case of the tracer-based assay, the changes in concentration of the tracer within and outside the cell are measured by radioactivity measurement or gas absorption spectrometry.
Nuclear receptor activation is believed to involve a conformational change of the receptor that is induced by ligand binding. The results of protease protection assays have confirmed that nuclear hormone agonists and antagonists cause receptor proteins to adopt different conformations (Keidel et al. Mol Cell. Biol. 14:287 (1994); Allan et al. J. Biol. Chem. 267:19513 (1992)). Accordingly, a protease protection assay can be used to measure the activity of a NHR. Recruitment of co-activators or repressors is another basis on which assays for assessment of NHR activity are developed.
Specific methods to determine the activity of a dehydrogenase by measuring the oxidation of a substrate by the dehydrogenase, which measurements are performed in the presence or absence of a compound, are well known in the art.
Specific methods to determine the inhibition by the compound by measuring the cleavage of the substrate by the polypeptide, which is a protease, are well known in the art. Classically, substrates are used in which a fluorescent group is linked to a quencher through a peptide sequence that is a substrate that can be cleaved by the target protease. Cleavage of the linker separates the fluorescent group and quencher, giving rise to an increase in fluorescence.
Table 4 lists a large number of other polypeptide types identified using applicant's knock-down library against the MMP1 assay described below. One such polypeptide class are the G-protein coupled receptors (GPCR), which are capable of activating an effector protein, resulting in changes in second messenger levels in the cell. The activity of a GPCR can be measured by measuring the activity level of such second messengers. Two important and useful second messengers in the cell are cyclic AMP (cAMP) and Ca2+. The activity levels can be measured by methods known to persons skilled in the art, either directly by ELISA or radioactive technologies or by using substrates that generate a fluorescent or luminescent signal when contacted with Ca2+ or indirectly by reporter gene analysis. The activity level of the one or more secondary messengers may typically be determined with a reporter gene controlled by a promoter, wherein the promoter is responsive to the second messenger. Promotors known and used in the art for such purposes are the cyclic-AMP responsive promoter that is responsive for the cyclic-AMP levels in the cell, and the NF-AT responsive promoter that is sensitive to cytoplasmic Ca2+-levels in the cell. The reporter gene typically has a gene product that is easily detectable. The reporter gene can either be stably infected or transiently transfected in the host cell. Useful reporter genes are alkaline phosphatase, enhanced green fluorescent protein, destabilized green fluorescent protein, luciferase and β-galactosidase.
It should be understood that the cells expressing the polypeptides, may be cells naturally expressing the polypeptides, or the cells may be may be transfected to express the polypeptides, as described above.
In one embodiment it is preferred that the methods of the present invention further comprise the step of contacting the population of cells with an agonist of the polypeptide. This is useful in methods wherein the expression of the polypeptide in a certain chosen population of cells is too low for a proper detection of its activity. By using an agonist the polypeptide may be triggered, enabling a proper read-out if the compound inhibits the polypeptide. Similar considerations apply to the measurement of ECM degradation. In a preferred embodiment, the cells used in the present method are mammalian synovial fibroblasts and the triggers that may be used to induce the ECM-degrading activity are cytokines relevant in the field of arthritis: for instance TNFalpha, IL1beta, IL6, OSM, IL17, IL15, IL18 and MIF1alpha. In another preferred embodiment, the trigger is a mixture of factors generated by contacting cytokine-producing cells relevant in the field of arthritis, such as monocytes, macrophages, T-cells, and B-cells. The cytokine-producing cells will respond to the contact by producing a complex and unbiased mixture of factors. If the cytokine-producing cell used is also found in the pannus, and the cytokine applied to this trigger is found in the synovial fluid of rheumatoid arthritis patients, the mixture of factors ultimately produced will contain factors that are present in the joints of arthritis patients.
The present invention further relates to a method for identifying a compound that inhibits extra-cellular matrix degradation, comprising:
The population of cells may be exposed to the compound or the mixture of compounds through different means, for instance by direct incubation in the medium, or by nucleic acid transfer into the cells. Such transfer may be achieved by a wide variety of means, for instance by direct transfection of naked isolated DNA, or RNA, or by means of delivery systems, such as recombinant vectors. Other delivery means such as liposomes, or other lipid-based vectors may also be used. Preferably, the nucleic acid compound is delivered by means of a (recombinant) vector such as a recombinant virus.
For high-throughput purposes, libraries of compounds may be used such as antibody fragment libraries, peptide phage display libraries, peptide libraries (for example, LOPAP™, Sigma Aldrich), lipid libraries (BioMol), synthetic compound libraries (for example, LOPAC™, Sigma Aldrich) or natural compound libraries (Specs, TimTec).
Preferred drug candidate compounds are low molecular weight compounds. Low molecular weight compounds, for example, with a molecular weight of 500 Dalton or less, are likely to have good absorption and permeation in biological systems and are consequently more likely to be successful drug candidates than compounds with a molecular weight above 500 Dalton (Lipinski et al. (1997)). Peptides comprise another preferred class of drug candidate compounds. Peptides may be excellent drug candidates and there are multiple examples of commercially valuable peptides such as fertility hormones and platelet aggregation inhibitors. Natural compounds are another preferred class of drug candidate compound. Such compounds are found in and extracted from natural sources, and which may thereafter be synthesized. The lipids are another preferred class of drug candidate compound.
Another preferred class of drug candidate compounds is an antibody. The present invention also provides antibodies directed against a TARGET. These antibodies may be endogenously produced to bind to the TARGET within the cell, or added to the tissue to bind to TARGET polypeptide present outside the cell. These antibodies may be monoclonal antibodies or polyclonal antibodies. The present invention includes chimeric, single chain, and humanized antibodies, as well as FAb fragments and the products of a FAb expression library, and Fv fragments and the products of an Fv expression library. In another embodiment, the compound may be a nanobody, the smallest functional fragment of naturally occurring single-domain antibodies (Cortez-Retamozo et al. 2004).
In certain embodiments, polyclonal antibodies may be used in the practice of the invention. The skilled artisan knows methods of preparing polyclonal antibodies. Polyclonal antibodies can be raised in a mammal, for example, by one or more injections of an immunizing agent and, if desired, an adjuvant. Typically, the immunizing agent and/or adjuvant will be injected in the mammal by multiple subcutaneous or intraperitoneal injections. Antibodies may also be generated against the intact TARGET protein or polypeptide, or against a fragment, derivatives including conjugates, or other epitope of the TARGET protein or polypeptide, such as the TARGET embedded in a cellular membrane, or a library of antibody variable regions, such as a phage display library.
It may be useful to conjugate the immunizing agent to a protein known to be immunogenic in the mammal being immunized. Examples of such immunogenic proteins include but are not limited to keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin, and soybean trypsin inhibitor. Examples of adjuvants that may be employed include Freund's complete adjuvant and MPL-TDM adjuvant (monophosphoryl Lipid A, synthetic trehalose dicorynomycolate). One skilled in the art without undue experimentation may select the immunization protocol.
In some embodiments, the antibodies may be monoclonal antibodies. Monoclonal antibodies may be prepared using methods known in the art. The monoclonal antibodies of the present invention may be “humanized” to prevent the host from mounting an immune response to the antibodies. A “humanized antibody” is one in which the complementarity determining regions (CDRS) and/or other portions of the light and/or heavy variable domain framework are derived from a non-human immunoglobulin, but the remaining portions of the molecule are derived from one or more human immunoglobulins. Humanized antibodies also include antibodies characterized by a humanized heavy chain associated with a donor or acceptor unmodified light chain or a chimeric light chain, or vice versa. The humanization of antibodies may be accomplished by methods known in the art (see, for example, Mark and Padlan, (1994) “Chapter 4. Humanization of Monoclonal Antibodies”, The Handbook of Experimental Pharmacology Vol. 113, Springer-Verlag, New York). Transgenic animals may be used to express humanized antibodies.
Human antibodies can also be produced using various techniques known in the art, including phage display libraries (Hoogenboom and Winter, (1991) J. Mol. Biol. 227:381-8; Marks et al. (1991). J. Mol. Biol. 222:581-97). The techniques of Cole, et al. and Boemer, et al. are also available for the preparation of human monoclonal antibodies (Cole, et al. (1985) Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p. 77; Boerner, et al (1991). J. Immunol., 147(1):86-95).
Techniques known in the art for the production of single chain antibodies can be adapted to produce single chain antibodies to the TARGET polypeptides and proteins of the present invention. The antibodies may be monovalent antibodies. Methods for preparing monovalent antibodies are well known in the art. For example, one method involves recombinant expression of immunoglobulin light chain and modified heavy chain. The heavy chain is truncated generally at any point in the Fc region so as to prevent heavy chain cross-linking. Alternatively, the relevant cysteine residues are substituted with another amino acid residue or are deleted so as to prevent cross-linking.
Bispecific antibodies are monoclonal, preferably human or humanized, antibodies that have binding specificities for at least two different antigens and preferably for a cell-surface protein or receptor or receptor subunit. In the present case, one of the binding specificities is for one domain of the TARGET, while the other one is for another domain of the same or different TARGET.
Methods for making bispecific antibodies are known in the art. Traditionally, the recombinant production of bispecific antibodies is based on the co-expression of two immunoglobulin heavy-chain/light-chain pairs, where the two heavy chains have different specificities (Milstein and Cuello, (1983) Nature 305:537-9). Because of the random assortment of immunoglobulin heavy and light chains, these hybridomas (quadromas) produce a potential mixture of ten different antibody molecules, of which only one has the correct bispecific structure. Affinity chromatography steps usually accomplish the purification of the correct molecule. Similar procedures are disclosed in Trauneeker, et al. (1991) EMBO J. 10:3655-9.
According to another preferred embodiment, the assay method uses a drug candidate compound identified as having a binding affinity for a TARGET, and/or has already been identified as having down-regulating activity such as antagonist activity vis-à-vis one or more TARGET.
The present invention further relates to a method for inhibiting extra-cellular matrix degradation comprising contacting mammalian cells with an expression inhibitory agent comprising a polyribonucleotide sequence that complements at least about 17 to about 30 contiguous nucleotides of the nucleotide sequence selected from the group consisting of SEQ ID NO: 1-16.
Another aspect of the present invention relates to a method for inhibiting extra-cellular matrix degradation, comprising by contacting mammalian cells with an expression-inhibiting agent that inhibits the translation in the cell of a polyribonucleotide encoding a TARGET polypeptide. A particular embodiment relates to a composition comprising a polynucleotide including at least one antisense strand that functions to pair the agent with the TARGET mRNA, and thereby down-regulate or block the expression of TARGET polypeptide. The inhibitory agent preferably comprises antisense polynucleotide, a ribozyme, and a small interfering RNA (siRNA), wherein said agent comprises a nucleic acid sequence complementary to, or engineered from, a naturally-occurring polynucleotide sequence selected from the group consisting of SEQ ID NO: 1-16.
A special embodiment of the present invention relates to a method wherein the expression-inhibiting agent is selected from the group consisting of antisense RNA, antisense oligodeoxynucleotide (ODN), a ribozyme that cleaves the polyribonucleotide coding for SEQ ID NO: 1-16, a small interfering RNA (siRNA, preferably shRNA,) that is sufficiently homologous to a portion of the polyribonucleotide corresponding to SEQ ID NO: 1-16, such that the siRNA, preferably shRNA, interferes with the translation of the TARGET polyribonucleotide to the TARGET polypeptide.
Another embodiment of the present invention relates to a method wherein the expression-inhibiting agent is a nucleic acid expressing the antisense RNA, antisense oligodeoxynucleotide (ODN), a ribozyme that cleaves the polyribonucleotide encoded by SEQ ID NO: 1-16, a small interfering RNA (siRNA, preferably shRNA,) that is sufficiently complementary to a portion of the polyribonucleotide corresponding to SEQ ID NO: 1-16, such that the siRNA, preferably shRNA, interferes with the translation of the TARGET polyribonucleotide to the TARGET polypeptide. Preferably the expression-inhibiting agent is an antisense RNA, ribozyme, antisense oligodeoxynucleotide, or siRNA, preferably shRNA, comprising a polyribonucleotide sequence that complements at least about 17 to about 30 contiguous nucleotides of a nucleotide sequence selected from the group consisting of SEQ ID NO: 1-16. More preferably, the expression-inhibiting agent is an antisense RNA, ribozyme, antisense oligodeoxynucleotide, or siRNA, preferably shRNA, comprising a polyribonucleotide sequence that complements at least about 17 to about 25 contiguous nucleotides of a nucleotide sequence selected from the group consisting of SEQ ID NO: 1-16. A special embodiment comprises a polyribonucleotide sequence that complements a polynucleotide sequence selected from the group consisting of SEQ ID NO: 128-141 and 231-244.
The down regulation of gene expression using antisense nucleic acids can be achieved at the translational or transcriptional level. Antisense nucleic acids of the invention are preferably nucleic acid fragments capable of specifically hybridizing with all or part of a nucleic acid encoding a TARGET polypeptide or the corresponding messenger RNA. In addition, antisense nucleic acids may be designed which decrease expression of the nucleic acid sequence capable of encoding a TARGET polypeptide by inhibiting splicing of its primary transcript. Any length of antisense sequence is suitable for practice of the invention so long as it is capable of down-regulating or blocking expression of a nucleic acid coding for a TARGET. Preferably, the antisense sequence is at least about 17 nucleotides in length. The preparation and use of antisense nucleic acids, DNA encoding antisense RNAs and the use of oligo and genetic antisense is known in the art.
One embodiment of expression-inhibitory agent is a nucleic acid that is antisense to a nucleic acid comprising SEQ ID NO: 1-16, for example, an antisense nucleic acid (for example, DNA) may be introduced into cells in vitro, or administered to a subject in vivo, as gene therapy to inhibit cellular expression of nucleic acids comprising SEQ ID NO: 1-16. Antisense oligonucleotides comprise preferably a sequence containing from about 17 to about 100 nucleotides and more preferably the antisense oligonucleotides comprise from about 18 to about 30 nucleotides. Antisense nucleic acids may be prepared from about 17 to about 30 contiguous nucleotides selected from the sequences of SEQ ID NO: 1-16, expressed in the opposite orientation.
The antisense nucleic acids are preferably oligonucleotides and may consist entirely of deoxyribo-nucleotides, modified deoxyribonucleotides, or some combination of both. The antisense nucleic acids can be synthetic oligonucleotides. The oligonucleotides may be chemically modified, if desired, to improve stability and/or selectivity. Since oligonucleotides are susceptible to degradation by intracellular nucleases, the modifications can include, for example, the use of a sulfur group to replace the free oxygen of the phosphodiester bond. This modification is called a phosphorothioate linkage. Phosphorothioate antisense oligonucleotides are water soluble, polyanionic, and resistant to endogenous nucleases. In addition, when a phosphorothioate antisense oligonucleotide hybridizes to its TARGET site, the RNA-DNA duplex activates the endogenous enzyme ribonuclease (RNase) H, which cleaves the mRNA component of the hybrid molecule.
In addition, antisense oligonucleotides with phosphoramidite and polyamide (peptide) linkages can be synthesized. These molecules should be very resistant to nuclease degradation. Furthermore, chemical groups can be added to the 2′ carbon of the sugar moiety and the 5 carbon (C-5) of pyrimidines to enhance stability and facilitate the binding of the antisense oligonucleotide to its TARGET site. Modifications may include 2′-deoxy, O-pentoxy, O-propoxy, O-methoxy, fluoro, methoxyethoxy phosphorothioates, modified bases, as well as other modifications known to those of skill in the art.
Another type of expression-inhibitory agent that reduces the levels of TARGETS is the ribozyme. Ribozymes are catalytic RNA molecules (RNA enzymes) that have separate catalytic and substrate binding domains. The substrate binding sequence combines by nucleotide complementarity and, possibly, non-hydrogen bond interactions with its TARGET sequence. The catalytic portion cleaves the TARGET RNA at a specific site. The substrate domain of a ribozyme can be engineered to direct it to a specified mRNA sequence. The ribozyme recognizes and then binds a TARGET mRNA through complementary base pairing. Once it is bound to the correct TARGET site, the ribozyme acts enzymatically to cut the TARGET mRNA. Cleavage of the mRNA by a ribozyme destroys its ability to direct synthesis of the corresponding polypeptide. Once the ribozyme has cleaved its TARGET sequence, it is released and can repeatedly bind and cleave at other mRNAs.
Ribozyme forms include a hammerhead motif, a hairpin motif, a hepatitis delta virus, group I intron or RNaseP RNA (in association with an RNA guide sequence) motif or Neurospora VS RNA motif. Ribozymes possessing a hammerhead or hairpin structure are readily prepared since these catalytic RNA molecules can be expressed within cells from eukaryotic promoters (Chen, et al. (1992) Nucleic Acids Res. 20:4581-9). A ribozyme of the present invention can be expressed in eukaryotic cells from the appropriate DNA vector. If desired, the activity of the ribozyme may be augmented by its release from the primary transcript by a second ribozyme (Ventura, et al. (1993) Nucleic Acids Res. 21:3249-55).
Ribozymes may be chemically synthesized by combining an oligodeoxyribonucleotide with a ribozyme catalytic domain (20 nucleotides) flanked by sequences that hybridize to the TARGET mRNA after transcription. The oligodeoxyribonucleotide is amplified by using the substrate binding sequences as primers. The amplification product is cloned into a eukaryotic expression vector.
Ribozymes are expressed from transcription units inserted into DNA, RNA, or viral vectors. Transcription of the ribozyme sequences are driven from a promoter for eukaryotic RNA polymerase I (pol (I), RNA polymerase II (pol II), or RNA polymerase III (pol III). Transcripts from pol II or pol III promoters will be expressed at high levels in all cells; the levels of a given pol II promoter in a given cell type will depend on nearby gene regulatory sequences. Prokaryotic RNA polymerase promoters are also used, providing that the prokaryotic RNA polymerase enzyme is expressed in the appropriate cells (Gao and Huang, (1993) Nucleic Acids Res. 21:2867-72). It has been demonstrated that ribozymes expressed from these promoters can function in mammalian cells (Kashani-Sabet, et al. (1992) Antisense Res. Dev. 2:3-15).
A particularly preferred inhibitory agent is a small interfering RNA (siRNA, preferably small hairpin RNA, “shRNA”). siRNA, preferably shRNA, mediate the post-transcriptional process of gene silencing by double stranded RNA (dsRNA) that is homologous in sequence to the silenced RNA. siRNA according to the present invention comprises a sense strand of 17-25 nucleotides complementary or homologous to a contiguous 17-25 nucleotide sequence selected from the group of sequences described in SEQ ID NO: 1-16, preferably from the group of sequences described in SEQ ID No: 128-141 and 231-244, and an antisense strand of 17-25 nucleotides complementary to the sense strand. The most preferred siRNA comprises sense and anti-sense strands that are 100 percent complementary to each other and the TARGET polynucleotide sequence. Preferably the siRNA further comprises a loop region linking the sense and the antisense strand.
A self-complementing single stranded shRNA molecule polynucleotide according to the present invention comprises a sense portion and an antisense portion connected by a loop region linker. Preferably, the loop region sequence is 4-30 nucleotides long, more preferably 5-15 nucleotides long and most preferably 8 nucleotides long. In a most preferred embodiment the linker sequence is UUGCUAUA (SEQ ID NO: 871) or GUUUGCUAUAAC (SEQ ID NO: 872). Self-complementary single stranded siRNAs form hairpin loops and are more stable than ordinary dsRNA. In addition, they are more easily produced from vectors.
Analogous to antisense RNA, the siRNA can be modified to confirm resistance to nucleolytic degradation, or to enhance activity, or to enhance cellular distribution, or to enhance cellular uptake, such modifications may consist of modified internucleoside linkages, modified nucleic acid bases, modified sugars and/or chemical linkage the siRNA to one or more moieties or conjugates. The nucleotide sequences are selected according to siRNA designing rules that give an improved reduction of the TARGET sequences compared to nucleotide sequences that do not comply with these siRNA designing rules (For a discussion of these rules and examples of the preparation of siRNA, WO2004094636, published Nov. 4, 2004, and UA20030198627, are hereby incorporated by reference).
The present invention also relates to compositions, and methods using said compositions, comprising a DNA expression vector capable of expressing a polynucleotide capable of inhibiting extra-cellular matrix degradation and described hereinabove as an expression inhibition agent.
A special aspect of these compositions and methods relates to the down-regulation or blocking of the expression of a TARGET polypeptide by the induced expression of a polynucleotide encoding an intracellular binding protein that is capable of selectively interacting with the TARGET polypeptide. An intracellular binding protein includes any protein capable of selectively interacting, or binding, with the polypeptide in the cell in which it is expressed and neutralizing the function of the polypeptide. Preferably, the intracellular binding protein is a neutralizing antibody or a fragment of a neutralizing antibody having binding affinity to an epitope of the TARGET polypeptide of SEQ ID NO: 17-32, preferably to a domain of SEQ ID NO: 33-127. More preferably, the intracellular binding protein is a single chain antibody.
A special embodiment of this composition comprises the expression-inhibiting agent selected from the group consisting of antisense RNA, antisense oligodeoxynucleotide (ODN), a ribozyme that cleaves the polyribonucleotide coding for SEQ ID NO: 17-32, and a small interfering RNA (siRNA) that is sufficiently homologous to a portion of the polyribonucleotide corresponding to SEQ ID NO: 1-16, such that the siRNA interferes with the translation of the TARGET polyribonucleotide to the TARGET polypeptide.
The polynucleotide expressing the expression-inhibiting agent is preferably included within a vector. The polynucleic acid is operably linked to signals enabling expression of the nucleic acid sequence and is introduced into a cell utilizing, preferably, recombinant vector constructs, which will express the antisense nucleic acid once the vector is introduced into the cell. A variety of viral-based systems are available, including adenoviral, retroviral, adeno-associated viral, lentiviral, herpes simplex viral or a sendaviral vector systems, and all may be used to introduce and express polynucleotide sequence for the expression-inhibiting agents in TARGET cells.
Preferably, the viral vectors used in the methods of the present invention are replication defective. Such replication defective vectors will usually pack at least one region that is necessary for the replication of the virus in the infected cell. These regions can either be eliminated (in whole or in part), or be rendered non-functional by any technique known to a person skilled in the art. These techniques include the total removal, substitution, partial deletion or addition of one or more bases to an essential (for replication) region. Such techniques may be performed in vitro (on the isolated DNA) or in situ, using the techniques of genetic manipulation or by treatment with mutagenic agents. Preferably, the replication defective virus retains the sequences of its genome, which are necessary for encapsidating, the viral particles.
In a preferred embodiment, the viral element is derived from an adenovirus. Preferably, the vehicle includes an adenoviral vector packaged into an adenoviral capsid, or a functional part, derivative, and/or analogue thereof. Adenovirus biology is also comparatively well known on the molecular level. Many tools for adenoviral vectors have been and continue to be developed, thus making an adenoviral capsid a preferred vehicle for incorporating in a library of the invention. An adenovirus is capable of infecting a wide variety of cells. However, different adenoviral serotypes have different preferences for cells. To combine and widen the TARGET cell population that an adenoviral capsid of the invention can enter in a preferred embodiment, the vehicle includes adenoviral fiber proteins from at least two adenoviruses. Preferred adenoviral fiber protein sequences are serotype 17, 45 and 51. Techniques or construction and expression of these chimeric vectors are disclosed in US Published Patent Applications 20030180258 and 20040071660, hereby incorporated by reference.
In a preferred embodiment, the nucleic acid derived from an adenovirus includes the nucleic acid encoding an adenoviral late protein or a functional part, derivative, and/or analogue thereof. An adenoviral late protein, for instance an adenoviral fiber protein, may be favorably used to TARGET the vehicle to a certain cell or to induce enhanced delivery of the vehicle to the cell. Preferably, the nucleic acid derived from an adenovirus encodes for essentially all adenoviral late proteins, enabling the formation of entire adenoviral capsids or functional parts, analogues, and/or derivatives thereof. Preferably, the nucleic acid derived from an adenovirus includes the nucleic acid encoding adenovirus E2A or a functional part, derivative, and/or analogue thereof. Preferably, the nucleic acid derived from an adenovirus includes the nucleic acid encoding at least one E4-region protein or a functional part, derivative, and/or analogue thereof, which facilitates, at least in part, replication of an adenoviral derived nucleic acid in a cell. The adenoviral vectors used in the examples of this application are exemplary of the vectors useful in the present method of treatment invention.
Certain embodiments of the present invention use retroviral vector systems. Retroviruses are integrating viruses that infect dividing cells, and their construction is known in the art. Retroviral vectors can be constructed from different types of retrovirus, such as, MoMuLV (“murine Moloney leukemia virus” MSV (“murine Moloney sarcoma virus”), HaSV (“Harvey sarcoma virus”); SNV (“spleen necrosis virus”); RSV (“Rous sarcoma virus”) and Friend virus. Lentiviral vector systems may also be used in the practice of the present invention. Retroviral systems and herpes virus system may be preferred vehicles for transfection of neuronal cells.
In other embodiments of the present invention, adeno-associated viruses (“AAV”) are utilized. The AAV viruses are DNA viruses of relatively small size that integrate, in a stable and site-specific manner, into the genome of the infected cells. They are able to infect a wide spectrum of cells without inducing any effects on cellular growth, morphology or differentiation, and they do not appear to be involved in human pathologies.
In the vector construction, the polynucleotide agents of the present invention may be linked to one or more regulatory regions. Selection of the appropriate regulatory region or regions is a routine matter, within the level of ordinary skill in the art. Regulatory regions include promoters, and may include enhancers, suppressors, etc.
Promoters that may be used in the expression vectors of the present invention include both constitutive promoters and regulated (inducible) promoters. The promoters may be prokaryotic or eukaryotic depending on the host. Among the prokaryotic (including bacteriophage) promoters useful for practice of this invention are lac, lacZ, T3, T7, lambda P.sub.r, P.sub.1, and trp promoters. Among the eukaryotic (including viral) promoters useful for practice of this invention are ubiquitous promoters (for example, HPRT, vimentin, actin, tubulin), intermediate filament promoters (for example, desmin, neurofilaments, keratin, GFAP), therapeutic gene promoters (for example, MDR type, CFTR, factor VIII), tissue-specific promoters (for example, actin promoter in smooth muscle cells, or Flt and Flk promoters active in endothelial cells), including animal transcriptional control regions, which exhibit tissue specificity and have been utilized in transgenic animals: elastase I gene control region which is active in pancreatic acinar cells (Swift, et al. (1984) Cell 38:639-46; Ornitz, et al. (1986) Cold Spring Harbor Symp. Quant. Biol. 50:399-409; MacDonald, (1987) Hepatology 7:425-515); insulin gene control region which is active in pancreatic beta cells (Hanahan, (1985) Nature 315:115-22), immunoglobulin gene control region which is active in lymphoid cells (Grosschedl, et al. (1984) Cell 38:647-58; Adames, et al. (1985) Nature 318:533-8; Alexander, et al. (1987) Mol. Cell. Biol. 7:1436-44), mouse mammary tumor virus control region which is active in testicular, breast, lymphoid and mast cells (Leder, et al. (1986) Cell 45:485-95), albumin gene control region which is active in liver (Pinkert, et al. (1987) Genes and Devel. 1:268-76), alpha-fetoprotein gene control region which is active in liver (Krumlauf, et al. (1985) Mol. Cell. Biol., 5:1639-48; Hammer, et al. (1987) Science 235:53-8), alpha 1-antitrypsin gene control region which is active in the liver (Kelsey, et al. (1987) Genes and Devel., 1: 161-71), beta-globin gene control region which is active in myeloid cells (Mogram, et al. (1985) Nature 315:338-40; Kollias, et al. (1986) Cell 46:89-94), myelin basic protein gene control region which is active in oligodendrocyte cells in the brain (Readhead, et al. (1987) Cell 48:703-12), myosin light chain-2 gene control region which is active in skeletal muscle (Sani, (1985) Nature 314.283-6), and gonadotropic releasing hormone gene control region which is active in the hypothalamus (Mason, et al. (1986) Science 234:1372-8).
Other promoters which may be used in the practice of the invention include promoters which are preferentially activated in dividing cells, promoters which respond to a stimulus (for example, steroid hormone receptor, retinoic acid receptor), tetracycline-regulated transcriptional modulators, cytomegalovirus immediate-early, retroviral LTR, metallothionein, SV-40, E1a, and MLP promoters.
Additional vector systems include the non-viral systems that facilitate introduction of polynucleotide agents into a patient, for example, a DNA vector encoding a desired sequence can be introduced in vivo by lipofection. Synthetic cationic lipids designed to limit the difficulties encountered with liposome-mediated transfection can be used to prepare liposomes for in vivo transfection of a gene encoding a marker (Feigner, et. al. (1987) Proc. Natl. Acad Sci. USA 84:7413-7); see Mackey, et al. (1988) Proc. Natl. Acad. Sci. USA 85:8027-31; Ulmer, et al. (1993) Science 259:1745-8). The use of cationic lipids may promote encapsulation of negatively charged nucleic acids, and also promote fusion with negatively charged cell membranes (Feigner and Ringold, (1989) Nature 337:387-8). Particularly useful lipid compounds and compositions for transfer of nucleic acids are described in International Patent Publications WO 95/18863 and WO 96/17823, and in U.S. Pat. No. 5,459,127. The use of lipofection to introduce exogenous genes into the specific organs in vivo has certain practical advantages and directing transfection to particular cell types would be particularly advantageous in a tissue with cellular heterogeneity, for example, pancreas, liver, kidney, and the brain. Lipids may be chemically coupled to other molecules for the purpose of targeting. Targeted peptides, for example, hormones or neurotransmitters, and proteins, for example, antibodies, or non-peptide molecules could be coupled to liposomes chemically. Other molecules are also useful for facilitating transfection of a nucleic acid in vivo, for example, a cationic oligopeptide (for example, International Patent Publication WO 95/21931), peptides derived from DNA binding proteins (for example, International Patent Publication WO 96/25508), or a cationic polymer (for example, International Patent Publication WO 95/21931).
It is also possible to introduce a DNA vector in vivo as a naked DNA plasmid (see U.S. Pat. Nos. 5,693,622; 5,589,466; and 5,580,859). Naked DNA vectors for therapeutic purposes can be introduced into the desired host cells by methods known in the art, for example, transfection, electroporation, microinjection, transduction, cell fusion, DEAE dextran, calcium phosphate precipitation, use of a gene gun, or use of a DNA vector transporter (see, for example, Wilson, et al. (1992) J. Biol. Chem. 267:963-7; Wu and Wu, (1988) J. Biol. Chem. 263:14621-4; Hartmut, et al. Canadian Patent Application No. 2,012,311, filed Mar. 15, 1990; Williams, et al (1991). Proc. Natl. Acad. Sci. USA 88:2726-30). Receptor-mediated DNA delivery approaches can also be used (Curiel, et al. (1992) Hum. Gene Ther. 3:147-54; Wu and Wu, (1987) J. Biol. Chem. 262:4429-32).
The present invention also provides biologically compatible, extra-cellular matrix degradation inhibiting compositions comprising an effective amount of one or more compounds identified as TARGET inhibitors, and/or the expression-inhibiting agents as described hereinabove.
A biologically compatible composition is a composition, that may be solid, liquid, gel, or other form, in which the compound, polynucleotide, vector, and antibody of the invention is maintained in an active form, for example, in a form able to effect a biological activity. For example, a compound of the invention would have inverse agonist or antagonist activity on the TARGET; a nucleic acid would be able to replicate, translate a message, or hybridize to a complementary mRNA of a TARGET; a vector would be able to transfect a TARGET cell and expression the antisense, antibody, ribozyme or siRNA as described hereinabove; an antibody would bind a TARGET polypeptide domain.
A preferred biologically compatible composition is an aqueous solution that is buffered using, for example, Tris, phosphate, or HEPES buffer, containing salt ions. Usually the concentration of salt ions will be similar to physiological levels. Biologically compatible solutions may include stabilizing agents and preservatives. In a more preferred embodiment, the biocompatible composition is a pharmaceutically acceptable composition. Such compositions can be formulated for administration by topical, oral, parenteral, intranasal, subcutaneous, and intraocular, routes. Parenteral administration is meant to include intravenous injection, intramuscular injection, intraarterial injection or infusion techniques. The composition may be administered parenterally in dosage unit formulations containing standard, well-known non-toxic physiologically acceptable carriers, adjuvants and vehicles as desired.
A particularly preferred embodiment of the present composition invention is a extra-cellular matrix degradation inhibiting pharmaceutical composition comprising a therapeutically effective amount of an expression-inhibiting agent as described hereinabove, in admixture with a pharmaceutically acceptable carrier. Another preferred embodiment is a pharmaceutical composition for the treatment or prevention of a condition involving ECM degradation, or a susceptibility to the condition, comprising an effective extra-cellular matrix degradation inhibiting amount of a TARGET antagonist or inverse agonist, its pharmaceutically acceptable salts, hydrates, solvates, or prodrugs thereof in admixture with a pharmaceutically acceptable carrier.
Pharmaceutical compositions for oral administration can be formulated using pharmaceutically acceptable carriers well known in the art in dosages suitable for oral administration. Such carriers enable the pharmaceutical compositions to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions, and the like, for ingestion by the patient. Pharmaceutical compositions for oral use can be prepared by combining active compounds with solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores. Suitable excipients are carbohydrate or protein fillers, such as sugars, including lactose, sucrose, mannitol, or sorbitol; starch from corn, wheat, rice, potato, or other plants; cellulose, such as methyl cellulose, hydroxypropylmethyl-cellulose, or sodium carboxymethyl-cellulose; gums including arabic and tragacanth; and proteins such as gelatin and collagen. If desired, disintegrating or solubilizing agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar, alginic acid, or a salt thereof, such as sodium alginate. Dragee cores may be used in conjunction with suitable coatings, such as concentrated sugar solutions, which may also contain gum arabic, talc, polyvinyl-pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for product identification or to characterize the quantity of active compound, i.e., dosage.
Pharmaceutical preparations that can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a coating, such as glycerol or sorbitol. Push-fit capsules can contain active ingredients mixed with filler or binders, such as lactose or starches, lubricants, such as talc or magnesium stearate, and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid, or liquid polyethylene glycol with or without stabilizers.
Preferred sterile injectable preparations can be a solution or suspension in a non-toxic parenterally acceptable solvent or diluent. Examples of pharmaceutically acceptable carriers are saline, buffered saline, isotonic saline (for example, monosodium or disodium phosphate, sodium, potassium; calcium or magnesium chloride, or mixtures of such salts), Ringer's solution, dextrose, water, sterile water, glycerol, ethanol, and combinations thereof 1,3-butanediol and sterile fixed oils are conveniently employed as solvents or suspending media. Any bland fixed oil can be employed including synthetic mono- or di-glycerides. Fatty acids such as oleic acid also find use in the preparation of injectables.
The composition medium can also be a hydrogel, which is prepared from any biocompatible or non-cytotoxic homo- or hetero-polymer, such as a hydrophilic polyacrylic acid polymer that can act as a drug absorbing sponge. Certain of them, such as, in particular, those obtained from ethylene and/or propylene oxide are commercially available. A hydrogel can be deposited directly onto the surface of the tissue to be treated, for example during surgical intervention.
Embodiments of pharmaceutical compositions of the present invention comprise a replication defective recombinant viral vector encoding the polynucleotide inhibitory agent of the present invention and a transfection enhancer, such as poloxamer. An example of a poloxamer is Poloxamer 407, which is commercially available (BASF, Parsippany, N.J.) and is a non-toxic, biocompatible polyol. A poloxamer impregnated with recombinant viruses may be deposited directly on the surface of the tissue to be treated, for example during a surgical intervention. Poloxamer possesses essentially the same advantages as hydrogel while having a lower viscosity.
The active expression-inhibiting agents may also be entrapped in microcapsules prepared, for example, by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethacylate) microcapsules, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions. Such techniques are disclosed in Remington's Pharmaceutical Sciences (1980) 16th edition, Osol, A. Ed.
Sustained-release preparations may be prepared. Suitable examples of sustained-release preparations include semi-permeable matrices of solid hydrophobic polymers containing the antibody, which matrices are in the form of shaped articles, for example, films, or microcapsules. Examples of sustained-release matrices include polyesters, hydrogels (for example, poly(2-hydroxyethyl-methacrylate), or poly(vinylalcohol)), polylactides (U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and gamma-ethyl-L-glutamate, non-degradable ethylene-vinyl acetate, degradable lactic acid-glycolic acid copolymers such as the LUPRON DEPOT™. (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate), and poly-D-(−)-3-hydroxybutyric acid. While polymers such as ethylene-vinyl acetate and lactic acid-glycolic acid enable release of molecules for over 100 days, certain hydrogels release proteins for shorter time periods. When encapsulated antibodies remain in the body for a long time, they may denature or aggregate as a result of exposure to moisture at 37° C., resulting in a loss of biological activity and possible changes in immunogenicity. Rational strategies can be devised for stabilization depending on the mechanism involved. For example, if the aggregation mechanism is discovered to be intermolecular S—S bond formation through thio-disulfide interchange, stabilization may be achieved by modifying sulfhydryl residues, lyophilizing from acidic solutions, controlling moisture content, using appropriate additives, and developing specific polymer matrix compositions.
As defined above, therapeutically effective dose means that amount of protein, polynucleotide, peptide, or its antibodies, agonists or antagonists, which ameliorate the symptoms or condition. Therapeutic efficacy and toxicity of such compounds can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, for example, ED50 (the dose therapeutically effective in 50% of the population) and LD50 (the dose lethal to 50% of the population). The dose ratio of toxic to therapeutic effects is the therapeutic index, and it can be expressed as the ratio, LD50/ED50. Pharmaceutical compositions that exhibit large therapeutic indices are preferred. The data obtained from cell culture assays and animal studies is used in formulating a range of dosage for human use. The dosage of such compounds lies preferably within a range of circulating concentrations that include the ED50 with little or no toxicity. The dosage varies within this range depending upon the dosage form employed, sensitivity of the patient, and the route of administration.
For any compound, the therapeutically effective dose can be estimated initially either in cell culture assays or in animal models, usually mice, rabbits, dogs, or pigs. The animal model is also used to achieve a desirable concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in humans. The exact dosage is chosen by the individual physician in view of the patient to be treated. Dosage and administration are adjusted to provide sufficient levels of the active moiety or to maintain the desired effect. Additional factors which may be taken into account include the severity of the disease state, age, weight and gender of the patient; diet, desired duration of treatment, method of administration, time and frequency of administration, drug combination(s), reaction sensitivities, and tolerance/response to therapy. Long acting pharmaceutical compositions might be administered every 3 to 4 days, every week, or once every two weeks depending on half-life and clearance rate of the particular formulation.
The pharmaceutical compositions according to this invention may be administered to a subject by a variety of methods. They may be added directly to targeted tissues, complexed with cationic lipids, packaged within liposomes, or delivered to targeted cells by other methods known in the art. Localized administration to the desired tissues may be done by direct injection, transdermal absorption, catheter, infusion pump or stent. The DNA, DNA/vehicle complexes, or the recombinant virus particles are locally administered to the site of treatment. Alternative routes of delivery include, but are not limited to, intravenous injection, intramuscular injection, subcutaneous injection, aerosol inhalation, oral (tablet or pill form), topical, systemic, ocular, intraperitoneal and/or intrathecal delivery. Examples of ribozyme delivery and administration are provided in Sullivan et al. WO 94/02595.
Antibodies according to the invention may be delivered as a bolus only, infused over time or both administered as a bolus and infused over time. Those skilled in the art may employ different formulations for polynucleotides than for proteins. Similarly, delivery of polynucleotides or polypeptides will be specific to particular cells, conditions, locations, etc.
As discussed hereinabove, recombinant viruses may be used to introduce DNA encoding polynucleotide agents useful in the present invention. Recombinant viruses according to the invention are generally formulated and administered in the form of doses of between about 104 and about 1014 pfu. In the case of AAVs and adenoviruses, doses of from about 106 to about 1011 pfu are preferably used. The term pfu (“plaque-forming unit”) corresponds to the infective power of a suspension of virions and is determined by infecting an appropriate cell culture and measuring the number of plaques formed. The techniques for determining the pfu titre of a viral solution are well documented in the prior art.
The present invention also provides methods of inhibiting extra-cellular matrix degradation, comprising administering, to a subject suffering from a disease condition involving extra-cellular matrix degradation, an extra-cellular matrix degradation inhibiting pharmaceutical composition as described herein, preferably a therapeutically effective amount of an expression-inhibiting agent of the present invention. The diseases involving extra-cellular matrix degradation, include psoriatic arthritis, juvenile arthritis, early arthritis, reactive arthritis, osteoarthritis, ankylosing spondylitis, osteoporosis, muscular skeletal diseases such as tendinitis and periodontal disease, cancer metastasis, airway diseases (COPD, asthma), renal and liver fibrosis, cardio-vascular diseases such as atherosclerosis and heart failure, and neurological diseases such as neuroinflammation and multiple sclerosis. More preferred diseases for treatment in accordance with the present invention are the degenerative joint diseases such as psoriatic arthritis, juvenile arthritis, early arthritis, reactive arthritis, osteoarthritis, ankylosing spondylitis. The most preferred degenerative joint disease for treatment in accordance with the present method is rheumatoid arthritis. The present invention also provides methods for treatment of inflammatory diseases.
Administering of the expression-inhibiting agent of the present invention to the subject patient includes both self-administration and administration by another person. The patient may be in need of treatment for an existing disease or medical condition, or may desire prophylactic treatment to prevent or reduce the risk for diseases and medical conditions affected by a disturbance in bone metabolism. The expression-inhibiting agent of the present invention may be delivered to the subject patient orally, transdermally, via inhalation, injection, nasally, rectally or via a sustained release formulation.
A preferred regimen of the present method comprises the administration to a subject in suffering from a disease condition characterized by inflammatory, with an effective inhibiting amount of an expression-inhibiting agent of the present invention for a period of time sufficient to reduce the abnormal levels of extracellular matrix degradation in the patient, and preferably terminate, the self-perpetuating processes responsible for said degradation. A special embodiment of the method comprises administering of an effective matrix metallo-protease inhibiting amount of a expression-inhibiting agent of the present invention to a subject patient suffering from or susceptible to the development of rheumatoid arthritis, for a period of time sufficient to reduce or prevent, respectively, collagen and bone degradation in the joints of said patient, and preferably terminate, the self-perpetuating processes responsible for said degradation.
The invention also relates to the use of an agent as described above for the preparation of a medicament for treating or preventing a disease involving extra-cellular matrix degradation. Preferably the pathological condition is arthritis. More preferably, the pathological condition is rheumatoid arthritis.
The polypeptides and polynucleotides useful in the practice of the present invention described herein may be free in solution, affixed to a solid support, borne on a cell surface, or located intracellularly. To perform the methods it is feasible to immobilize either the TARGET polypeptide or the compound to facilitate separation of complexes from uncomplexed forms of the polypeptide, as well as to accommodate automation of the assay. Interaction (for example, binding of) of the TARGET polypeptide with a compound can be accomplished in any vessel suitable for containing the reactants. Examples of such vessels include microtitre plates, test tubes, and microcentrifuge tubes. In one embodiment, a fusion protein can be provided which adds a domain that allows the polypeptide to be bound to a matrix. For example, the TARGET polypeptide can be “His” tagged, and subsequently adsorbed onto Ni-NTA microtitre plates, or ProtA fusions with the TARGET polypeptides can be adsorbed to IgG, which are then combined with the cell lysates (for example, (35)S-labelled) and the candidate compound, and the mixture incubated under conditions favorable for complex formation (for example, at physiological conditions for salt and pH). Following incubation, the plates are washed to remove any unbound label, and the matrix is immobilized. The amount of radioactivity can be determined directly, or in the supernatant after dissociation of the complexes. Alternatively, the complexes can be dissociated from the matrix, separated by SDS-PAGE, and the level of the protein binding to the TARGET protein quantified from the gel using standard electrophoretic techniques.
Other techniques for immobilizing protein on matrices can also be used in the method of identifying compounds. For example, either the TARGET or the compound can be immobilized utilizing conjugation of biotin and streptavidin. Biotinylated TARGET protein molecules can be prepared from biotin-NHS(N-hydroxy-succinimide) using techniques well known in the art (for example, biotinylation kit, Pierce Chemicals, Rockford, Ill.), and immobilized in the wells of streptavidin-coated 96 well plates (Pierce Chemical). Alternatively, antibodies reactive with the TARGETS but which do not interfere with binding of the TARGET to the compound can be derivatized to the wells of the plate, and the TARGET can be trapped in the wells by antibody conjugation. As described above, preparations of a labeled candidate compound are incubated in the wells of the plate presenting the TARGETS, and the amount of complex trapped in the well can be quantitated.
The polynucleotides encoding the TARGET polypeptides are identified as SEQ ID NO: 1-16. The present inventors show herein that transfection of mammalian cells with Ad-siRNAs targeting these genes decreases the release of factors that promote extra-cellular matrix degradation.
The present invention also relates to a method for diagnosis of a pathological condition involving ECM degradation, comprising determining the nucleic acid sequence of at least one of the genes of SEQ ID NO: 1-16 within the genomic DNA of a subject; comparing the sequence with the nucleic acid sequence obtained from a database and/or a healthy subject; and identifying any difference(s) related to the onset of the pathological condition.
Still another aspect of the invention relates to a method for diagnosing a pathological condition involving extra-cellular matrix degradation or a susceptibility to the condition in a subject, comprising determining the amount of polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 17-32 in a biological sample, and comparing the amount with the amount of the polypeptide in a healthy subject, wherein an increase of the amount of polypeptide compared to the healthy subject is indicative of the presence of the pathological condition.
The invention is further illustrated in the following figures and examples.
The following assays, when used in combination with arrayed adenoviral shRNA (small hairpin RNA) expression libraries (the production and use of which are described in WO99/64582), are useful for the discovery of factors that modulate the capacity of synovial fibroblasts (SFs) to produce MMP1 and degrade collagen, an important component of cartilage. Candidate factors are filtered first through a primary followed by a secondary assay.
Example 1 describes the development and setup of the primary assay screen of an adenoviral siRNA library using an ELISA for detection of protein levels of Matrix Metalloprotease 1 (MMP1), and is referred to herein as the “reverse MMP1 assay”. Example 2 describes the screening and its results. Example 3 describes a further screen that eliminates any targets that inhibit MMP1 expression in a nonspecific way. Example 4 describes the testing of a subset of the targets for the endogenous SF expression. Example 5 describes a dose response experiment that tests a subset of the Ad-siRNAs for the inhibition of cytokine-induced MMP1 expression. Example 6 describes the secondary assay referred to herein as the “collagen degradation assay”, which is more functionally oriented, and which detects collagen degradation in the supernatant of SFs. Example 7 describes the testing of a subset of the Ad-siRNAs for the inhibition of cytokine-induced IL-8 expression.
Control Viruses Used:
The control viruses used in these studies are listed below. dE1/dE2A adenoviruses are generated by co-transfection of adapter plasmids described below with the helper plasmid pWEAd5AflII-rITR.dE2A in PER.E2A packaging cells, as described in WO99/64582.
(A) Negative Control Viruses:
The MMP1 assay is developed by first testing the capacity of synovial fibroblasts (SFs) to produce MMP1.
To evaluate the capacity of SFs to produce MMP1, these cells were infected with a recombinant adenovirus mediating the expression of the MYD88 adaptor molecule involved in the pro-inflammatory IL1 signaling pathway. This virus is expected to increase MMP1 expression in these cells (see Vincenti and Brinckerhoff, 2002).
40,000 SFs are seeded per well of a 6-well plate in DMEM+10% FBS and each well is either infected with a recombinant adenovirus mediating the expression of eGFP, MYD88 or MMP1 (with a multiplicity of infection (MOI) of 7500 viral particles per cell (vp/cell)) or left uninfected (blank). The SF expression of MMP1 is first determined at the mRNA level, by means of real-time, quantitative PCR. RNA of the cells infected with the control viruses is prepared 48 hours post infection using the SV RNA isolation kit (Promega), according to the instructions of the manufacturer. cDNA is prepared from this RNA using Multiscribe reverse transcriptase (50 U/μl, Applied Biosystems) and random hexamers. cDNA synthesis is performed in 25 μl total volume consisting of 1× TaqMan buffer A (PE Applied Biosystems), 5 mM MgCl2, dNTPs (500 μM final per dNTP), 2.5 mM random hexamers, 0.4 U/μl RNase Inhibitor, and 1.25 U/μl MultiScribe Reverse Transcriptase. The mixture is incubated for 10 minutes at 25° C., 30 minutes at 48° C., and 5 minutes at 95° C. Specific DNA products are amplified from the resulting cDNA with AmpliTaq Gold DNA polymerase (Applied BioSystems) during 40 PCR cycles using suited primer pairs. Amplification of the specific DNA products is monitored on an ABI PRISM® 7000 Sequence Detection System. The subsequent real time PCR reaction contained 5 μl of the RT reaction product in a total volume of 25 μl consisting of 1× SYBR Green mix (Applied Biosystems), 300 nM forward primer, and 300 nM reverse primer. Each sample is analyzed in duplicate. The PCR reaction is performed using the following program: 10 minutes at 95° C. followed by 40 cycles of (15 sec. 95° C., 1 minutes 60° C.). After each PCR reaction the products are analyzed by measuring the dissociation curve by incubating for 15 sec. 95° C., and 15 sec. at 60° C., followed by increasing the temperature to 95° C. over a 20 minutes time period, ending with 15 sec. at 95° C. The sequences of the primer pairs used for the detection of MMP1 expression are listed in Table 3.
MMP1 is detected using the SYBR Green method, whereas the levels of 18S rRNA, used as internal calibrator for the PCR reaction, is measured using a commercially available set of primers and Taqman probe (TaqMan® Ribosomal RNA Control Reagents, Applied Biosystems). The amplification plot and the resulting threshold Ct value are indicators for the amount of specific mRNAs present in the samples. Delta-delta Ct values are presented, meaning the normalized (relative to the 18S calibrator) levels of MMP1 mRNA in the samples infected with the positive control viruses relative to the expression levels in a Ad5-eGFP infected control sample. Results indicate a strong up-regulation of the MMP1 mRNA levels upon expression of MYD88 in SFs as compared to the non-infected or Ad5-eGFP-infected SFs (
The level of MMP1 expressed by SFs is also determined at the protein level by Western Blotting. Two days after infection, supernatant of cells, infected with various recombinant adenoviruses as indicated for the Real-time PCR experiment, is collected and concentrated 15 times by classical TCA precipitation. 15 μl of the supernatant are resolved by SDS-PAGE using a 10% polyacrylamide gel. For these experiments, the medium used is M199 medium+1% FBS. For the MMP1 control sample, non-concentrated supernatant of cells infected with Ad5-MMP1 is loaded onto the gel. The resolved proteins are transferred onto a nitrocellulose membrane. The quality of the transfer and equal loading of the samples are verified by Ponceau-S staining of the membrane. Immunodetection is performed using a goat anti-MMP1 polyclonal antibody as primary antibody (R&D Systems, 1/500 dilution) and an HRP-linked rabbit anti-goat antibody (DAKO, 1/10000 dilution) as secondary antibody and ECL plus HRP substrate (Amersham Biosciences). The Western Blotting revealed a strongly increased level of MMP1 protein in the supernatant of the SFs infected with the adenoviruses mediating expression of Ad5-MYD88 as compared to the Ad5-eGFP infected cells. A very strong signal is detected for the supernatant of cells infected with Ad5-MMP1 (
The high levels of MMP1 protein present in the supernatant of the Ad5-MYD88 infected SFs are confirmed using a commercially available MMP1 activity ELISA (RPN2629, Amersham Biosciences). In this ELISA, MMP1 is captured by an antibody immobilized in a well and the amount is subsequently quantified based on the conversion of a MMP1 substrate. 50 μl of non-concentrated supernatant of SFs (prepared as indicated for the western blotting experiment) are processed in this ELISA as recommended by the manufacturer (
These experiments confirm the capacity of SFs, in general, and of the cell batch used for screening and validation experiments, in particular, to produce MMP1 protein upon triggering of inflammatory pathways.
A 384-well format ELISA for measurement of MMP1 is developed. Various primary antibodies are tested, as well as various ELISA protocols. The following protocol is developed and validated to measure MMP1 levels in SF supernatant in 384 well plates: white Lumitrac 600 384 well plates (Greiner) are coated with 2 μg/ml anti-MMP1 antibody MAB1346 (Chemicon). The antibody is diluted in buffer 40 (1.21 g Tris base (Sigma), 0.58 g NaCl (Calbiochem) and 5 ml 10% NaN3 (Sigma) in 1 L milliQ water and adjusted to pH 8.5). After overnight incubation at 4° C., plates are washed with PBS (80 g NaCl, 2 g KCl (Sigma), 11.5 g Na2HPO4.7H2O and 2 g KH2PO4 in 10 L milliQ; pH 7.4) and blocked with 100 μl/well Casein buffer (2% Casein (VWR International) in PBS). Next day, casein buffer is removed from ELISA plates and replaced by 50 μl/well EC buffer (4 g casein, 2.13 g Na2HPO4 (Sigma), 2 g bovine albumin (Sigma), 0.69 g NaH2PO4.H2O (Sigma), 0.5 g CHAPS (Roche), 23.3 g NaCl, 4 ml 0.5 M EDTA pH 8 (Invitrogen), 5 ml 10% NaN3 in 1 L milliQ and adjusted to pH 7.0). 0.25 mM DTT (Sigma) are added to the thawed samples plates. After removal of the EC buffer, 20 μl of sample are transferred to the ELISA plates. After overnight incubation at 4° C., the plates are washed twice with PBS, once with PBST (PBS with 0.05% Tween-20 (Sigma)), and incubated with 35 μl/well biotinylated anti-MMP1 antibody solution (R&D). This secondary antibody is diluted in buffer C (0.82 g NaH2PO4.H2O, 4.82 g Na2HPO4, 46.6 g NaCl, 20 g bovine albumin and 4 ml 0.5M EDTA pH 8 in 2 L milliQ and adjusted to pH 7.0) at a concentration of 5 μg/ml. After 2 hours of incubation at RT, the plates are washed as described above and incubated with 50 μl/well streptavidin-HRP conjugate (Biosource). Streptavidin-HRP conjugate is diluted in buffer C at a concentration of 0.25 μg/ml. After 45 minutes, the plates are washed as described above and incubated for 5 minutes with 50 μl/well BM Chem ELISA Substrate (Roche). Readout is performed on the Luminoscan Ascent Luminometer (Labsystems) with an integration time of 200 msec or with an Envision reader (Perkin Elmer).
Typical results obtained with the MMP1 ELISA developed are shown in
The increase of MMP1 expression by SFs upon treatment with cytokines relevant in the field of RA (TNFα, IL1β and OSM) or a combination thereof is monitored. Results are shown in
In parallel with the above experiment, SFs are triggered, using the same protocol, with the supernatant of THP1 cells (2-fold diluted in M199+1% FBS) that are treated with the same cytokines or combinations of cytokines for 48 hours in M199 medium+1% FBS. MMP1 levels for these samples are shown in
The activation of SFs by the “TNFα-based trigger” can be inhibited in a dose-dependent manner by treating the SFs with dexamethasone, a potent anti-inflammatory agent that also strongly reduces collagen-induced arthritis in rodents (Yang et al., 2004) (
Primary Screening
An arrayed collection of 11,744 different recombinant adenoviruses mediating the expression of shRNAs in SFs are screened using the reverse MMP1 assay. These shRNAs cause a reduction in expression levels of genes that contain homologous sequences by a mechanism known as RNA interference (RNAi). The 11,744 Ad-siRNAs contained in the arrayed collection target 5046 different transcripts. On average, every transcript is targeted by two to three independent Ad-siRNAs. A schematic representation of the screening process is illustrated in
A 384 well control plate is generated to assess the quality of the assay during different screening runs. The composition of this plate is shown in
Optimal screening protocol: RASFs at passage 1 (Cell Applications) are cultured in DMEM medium (Invitrogen), supplemented with 10% fetal calf serum (ICN), 100 units/ml penicillin (Invitrogen) and 100 μg/ml streptomycin (Invitrogen), and incubated at 37° C. and 10% CO2. The cells are passed once a week by a ⅓ split. The maximal passage number for RASFs used in the screening is 11. For screening, the SFs are seeded in transparent 384 well plates (Greiner) coated with 0.1% gelatin (Merck) at a density of 1150 cells/well in 501 μl Synovial Cell growth medium (Cell Applications, Inc.). One day later, 2 μl Ad-siRNA virus from the SilenceSelect collection (WO 03/020931) are transferred to each individual well of the 384 well plates containing the SFs. The average titer of the adenoviral is 1×109 viral particles/ml, representing a MOI of about 1700. The SilenceSelect collection is stored in 384 well plates and transferred to the SFs by using a 96/384-channel dispenser. Five days after infection, the medium is removed and the wells are rinsed once by addition and subsequent removal of 80 μl of M199 medium supplemented with 1% FBS. The wells are then filled with 60 μl of “TNFalpha based trigger” diluted 2-fold in M199 medium containing 1% FBS. Two days after addition of the “TNFalpha based trigger”, the supernatant is collected in 384 well plates (Greiner) and stored at −80° C. until further processing in the MMP1 ELISA. The infection, rinsing, and medium collection steps are performed with a TECAN Freedom pipette (Tecan Freedom 200 equipped with TeMO96, TeMO384 and RoMa, Tecan AG, Switzerland). 25 μl of the collected supernatant is subjected to the MMP1 ELISA. The ELISA step is performed as indicated in Example 1.
The “TNFalpha based trigger” is produced from THP-1 cells at passage 8 to 16 grown in suspension cultures in RPMI supplemented with 10% FBS (Invitrogen) and penicillin (100 units/ml) and Streptomycin (100 μg/ml) (Invitrogen). The cultures are diluted weekly to a cell density of 2×105 cells/ml, avoiding densities exceeding 1.5×106 cells/ml. The production of the “TNFalpha based trigger” is initiated by seeding the THP-1 cells in M199 medium supplemented with 1% serum at a density of 1×106 cells/ml. One day after seeding, recombinant human TNFalpha (Sigma) is added to the culture flasks to a final concentration of 25 ng/ml. 48 hours after addition of the cytokine, the supernatant is collected and stored at −80° C. in aliquots until further use. Every new batch of “TNFalpha based trigger” is characterized for its efficacy at inducing MMP1 expression by SFs.
A representative example of the performance of the control plate tested with the screening protocol described above is shown in
A stringent cutoff is applied, that is, the average of all 144 negative control viruses minus 1.82 times the standard deviation. Samples scoring below this cutoff are considered positive hits. These positive hits are indicated as white numbers on a gray background. As expected, the positive control viruses score very well in the assay with 88%, 81% and 94% of the samples falling below the cutoff for the P1, P2 and P3 positive controls samples, respectively. As non-infected wells display lower signals as compared to infected wells, the blanco samples often score positive. The reason for this is not known. To rule out that a sample would be positive because of the absence of virus, the virus content of all wells is monitored by checking the cytopathic effect (CPE) when propagating hit viruses as well as checking the amount of adenoviral particles per well in a quantitative real-time PCR (Ma et al., 2000). Of the 3 negative control viruses, the N1 virus gives rise to some false positives due to toxicity. During screening, about 5% false positives for the N1 negative control are allowed. In this Example, 2 samples in 48 (+/−4%) score positive for the N1 control.
The complete SilenceSelect collection, consisting of 11,744 Ad-siRNAs targeting 5046 transcripts contained on 30×384 well plates, is screened in the “reverse MMP1 assay” according to the protocol described above. Every Ad-siRNA plate is screened in duplicate in a primary screen and a repeat screen. As such, four data points are obtained for each Ad-siRNA. Ad-siRNA viruses are nominated as hits if at least 1 data point in both the primary screen and repeat screen scored below threshold. A representative example of screening results and of the analysis performed to identify hits is shown in
To determine the cutoff value for hit calling, the average as well as standard deviation is calculated on all data points per plate. The cutoff value is then defined as the average minus 1.82 times the standard deviation. This cutoff is indicated as a horizontal line in the graphs shown in
In
“3” MOI Repeat Screen
The 408 hits identified above are re-propagated. The crude lysates of the hit Ad-siRNAs samples from the SilenceSelect collection are picked and arranged together with negative controls in 9×96 well plates. As the containers of crude lystates are labeled with a barcode (Screenmates™, Matrix technologies), quality checks are performed on the plates. The general layout of such a “3” MOI repeat screen plate is shown in
For the “3” MOI repeat screen, SFs are seeded in 96 well plates (Greiner, tissue culture treated) at a density of 3000 cells/well in 100 μl Synovial Cell growth medium (Cell Applications, Inc.). One day later, the SFs are infected with 3, 6, or 12 μl of the crude lysate contained in the re-propagation plates described above using a 96 well dispenser (TECAN freedom 200). Five days after infection, medium is removed from the plates, using a VacuSafe device (Integra), and 100 μl of two-fold diluted TNFalpha based trigger is added. After an incubation of 2 days, medium is collected with a 96 well dispenser (TECAN Freedom 200) and stored at −80° C. in 384 well plates until further processed in the reverse MMP1 ELISA according to the protocol described in Example 1.
The data from the MMP1 ELISA is analyzed as follows: To determine the cutoff value for hit calling, the average of the negative controls is calculated for every plate. For every MOI, a percentage is selected such that less than 3% of the negative controls would score as a hit over the 9 plates. The percentages are 23%, 26% and 19% for the 3 μl, 6 μl, and 12 μl infections, respectively. Of the 408 hits tested, 339 scored in duplicate at one MOI and are identified as a hit. 84% of the hits of the primary screen are thus confirmed in this 3 MOI repeat screen using repropagated Ad-siRNA material.
Quality Control of Target Ad-siRNAs
Target Ad-siRNAs are propagated using derivatives of PER.C6© cells (Crucell, Leiden, The Netherlands) in 96-well plates, followed by sequencing the siRNAs encoded by the target Ad-siRNA viruses. PERC6.E2A cells are seeded in 96 well plates at a density of 40,000 cells/well in 180 μl PER.E2A medium. Cells are then incubated overnight at 39° C. in a 10% CO2 humidified incubator. One day later, cells are infected with 1 μl of crude cell lysate from SilenceSelect stocks containing target Ad-siRNAs. Cells are incubated further at 34° C., 10% CO2 until appearance of cytopathic effect (as revealed by the swelling and rounding up of the cells, typically 7 days post infection). The supernatant is collected, and the virus crude lysate is treated with proteinase K by adding to 4 μl Lysis buffer (1× Expand High Fidelity buffer with MgCl2 (Roche Molecular Biochemicals, Cat. No 1332465) supplemented with 1 mg/ml proteinase K (Roche Molecular Biochemicals, Cat No 745 723) and 0.45% Tween-20 (Roche Molecular Biochemicals, Cat No 1335465) to 12 μl crude lysate in sterile PCR tubes. These tubes are incubated at 55° C. for 2 hours followed by a 15 minutes inactivation step at 95° C. For the PCR reaction, 1 μl lysate is added to a PCR master mix composed of 5 μl 10× Expand High Fidelity buffer with MgCl2, 0.5 μl of dNTP mix (10 mM for each dNTP), 1 μl of “Forward primer” (10 mM stock, sequence: 5′ CCG TTT ACG TGG AGA CTC GCC 3′) (SEQ. ID NO. 879), 1 μl of “Reverse Primer” (10 mM stock, sequence: 5′ CCC CCA CCT TAT ATA TAT TCT TTC C) (SEQ. ID NO. 880), 0.2 μl of Expand High Fidelity DNA polymerase (3.5 U/μl, Roche Molecular Biochemicals) and 41.3 μl of H2O. PCR is performed in a PE Biosystems GeneAmp PCR system 9700 as follows: the PCR mixture (50 μl in total) is incubated at 95° C. for 5 minutes; each cycle runs at 95° C. for 15 sec., 55° C. for 30 sec., 68° C. for 4 minutes, and is repeated for 35 cycles. A final incubation at 68° C. is performed for 7 minutes 5 μl of the PCR mixture is mixed with 2 μl of 6× gel loading buffer, loaded on a 0.8% agarose gel containing 0.5 μg/μl ethidium bromide to resolve the amplification products. The size of the amplified fragments is estimated from a standard DNA ladder loaded on the same gel. The expected size is approximately 500 bp. For sequencing analysis, the siRNA constructs expressed by the target adenoviruses are amplified by PCR using primers complementary to vector sequences flanking the SapI site of the pIPspAdapt6-U6 plasmid. The sequence of the PCR fragments is determined and compared with the expected sequence. All sequences are found to be identical to the expected sequence.
To eliminate general toxicity (reduced viability) of SFs by the Ad-siRNAs as the cause of reduced expression of MMP1 in the reverse MMP1 assay, the CellTiter-Glo Luminescent Cell Viability Assay (Promega) is used. This Assay determines the number of viable cells in culture based on the quantity of ATP present, which is proportional to the presence of metabolically active cells. In this assay, cells are grown in a white 96 well plate at a density of 3000 cells/well in 100 μl Synovial Cell growth medium (Cell Applications, Inc.). After overnight incubation, cells are infected with the confirmed hits from the reverse MMP1 assay. Five days after infection, the medium is removed and replaced by 50 μl M199 medium supplemented with 1% FBS. The plate and its content are equilibrated to room temperature for 30 minutes. 50 μl celltiter-Glo reagent is added to the wells, followed by an incubation on an orbital shaker (5 minutes) in the dark. The measurement is performed on a luminoskan Ascent (Labsystems) luminometer, 100 ms integration time.
In a primary test, 12 μl of the viruses contained in the 3 MOI repeat screen plates (layout depicted in
The secretion of TIMP-2 by SFs is determined to eliminate the factor of general suppression of SF secretory activity by the Ad-siRNAs as the cause of reduced expression of MMP1 in the reverse MMP1 assay. TIMP-2 is a protein that SFs express and secret constitutively. Secretion of TIMP-2 into the SF supernatant is blocked by the addition of BrefeldinA, a small molecule inhibitor of secretion. The level of SF TIMP-2 protein secretion is detected by ELISA. RASF cells are seeded in 96-well gelatin coated plates at 3000 cells/well in 100 μl synovial growth medium. After overnight incubation, cells are infected and incubated for 5 days at 37° C. in a 10% CO2 incubator. Virus is removed and 100 μl M199+1% FBS(HI) medium is applied on top of the cells. The supernatant is harvested after another 48 hours incubation and stored at −20° C. TIMP2 levels are determined by a standard ELISA assay, essentially as outlined for the MMP1 ELISA. In brief, 384-well white Greiner plates (Lumitrac 600) are coated overnight at 4° C. with 40 μl of anti-hTIMP2 capture antibody (Cat. No. MAB9711; R&D systems) at 1 μg/ml in PBS. Blocking is done for 4 hours at room temperature with 80 μl 0.1% caseine buffer and after a washing step (30 μl EC-buffer), 40 μl of the samples are added to the wells. Plates are incubated overnight at 4° C., and after washing twice with PBST (0.05% Tween-20) and PBS, 40 μl of the biotinylated anti-hTIMP2 detection antibody (100 ng/ml in Buffer C) (Cat.no. BAF971; R&D systems) is added to the wells. After 2 hours of incubation at room temperature, plates are washed again and incubated at room temperature for another 45 minutes after an addition of 40 μl of Streptavidin-HRP conjugate (Cat. No. SNN2004; BioSource) diluted 1/3000 in Buffer C. Finally, plates are washed and 501 μl of BM Chemiluminescence ELISA substrate (POD)(Cat. No. 1582950; Roche Diagnostic) is added to the wells. After 5 minutes incubation at room temperature in the dark, luminescence is quantified on a luminometer (Luminoscan Ascent).
The procedure described above (plate layout, MOI, method for determination of the cutoff) applied for these experiments is identical to the one described for the toxicity measurements (i.e., a primary test with 12 μl infection volume and a retest with 3, 6, 12 μl infection volumes) differing only in that the cutoff applied in the primary test is determined as the average over all samples minus 2 times standard deviation over all samples. In this assay, viruses mediating a reduction of the TIMP2 levels under the cutoff in duplicate for at least one MOI in the retest are considered as influencing the SF general secretion machinery.
From the 339 hits tested in the toxicity and TIMP secretion assay, 16 scored positive in these assays and considered mediating the reduction in cytokine induced MMP1 expression in an aspecific way. As such, 323 hits were identified as modulators of cytokine induced MMP1 expression, 16 of which are most preferred hits and listed in Table 1.
We conclude, from this experiment, that the genes associated with these hits and their expressed proteins represent valuable drug targets that are shown by these studies to modulate MMP1 expression in SFs.
The 323 hits identified through the primary “reverse MMP1 assay” are further prioritized using the “reverse collagen degradation assay”, which is based on the observation that the supernatant of RA SFs treated with “TNFα-based trigger” has collagenolytic potential. As degradation of native collagen is mediated by multiple proteases (collagenases), the reduction in the degradation of collagen is a more stringent readout compared to reading out only MMP1 expression. The effect of TARGET expression reduction in RA SFs (by means of KD-viruses) on the cytokine-induced collagen degradation by RA SFs is tested using an assay developed in house. In this assay, the degradation of FITC-labeled native collagen gives rise to an increase in fluorescence signal. (The protocol of this assay is detailed in the description of Example 6 (
The 323 hit KD viruses identified in the “reverse MMP1 assay” are arrayed in 96 well plates (“Hit plates”) such that every plate contained 60 hit viruses along with 4 positive control viruses and 16 negative control viruses. RA SF, seeded in 96 well plates at a density of 3000 cells/well in complete synovial growth medium (Cell Applications) are infected, one day later, with 5 or 10 μl of the viruses contained in the “hit plates”. The virus load is completed by addition 6 μl of the neutral virus Ad5-Luciferase-v13_KD. This correction guarantees that the effects observed do not result from differences in the virus load applied to the cells. 5 days after infection, the activation step is performed. This step involves the replacement, in every well, of the growth medium by 45 μl of M199 medium supplemented with 15 μl of “TNFαα-based trigger”. 4 days later, the supernatant is collected and subjected to the miniaturized collagen type I degradation assay according to the protocol described for the experiment depicted in
For every plate, the samples with corresponding fluorescence value lower then the average over all negative controls minus 2.1 times (5 μl infection) or 1.6 times (10 μl infection) the standard deviation over all negative controls are considered as giving a positive response in the assay. Every Target KD virus giving rise to 3 out of 4 data points giving a positive readout in the assay is considered as significantly reducing “TNF-based trigger”-induced collagen degradation by RA SFs. Alternatively, every Target KD virus generating 2 positive responses in the assay (out of 4 data points) for each MOI tested are considered as significantly reducing collagen degradation. Of the 323 target KD viruses tested, 192 significantly reduced the “TNF-based trigger”-induced collagen degradation by RA SFs.
To select for the preferred hits, we used a second assay that tests for the effect of the target expression reduction in RA SFs (by means of KD-viruses) on the LPS or TNFα-induced IL8 expression by RA SFs. This assay (1) confirms that the target KD viruses selected are not inhibiting the LPS signaling in RA SFs too much, as LPS signaling is required for the response of patients to pathogens and its complete inhibition would compromise the patients' innate immunity.; and (2) confirms that the targets do not enhance the TNFα-induced expression of an inflammation marker. The chemokine IL8 is selected as a readout in this assay. This chemokine plays a role in the recruitment of cells of the immune system (e.g. monocytes, neutrophils) to the site of inflammation (the joint in the case of RA), further increasing the local inflammatory events. Increase of IL8 expression is not a desired feature for a RA therapy.
The target KD viruses identified in the “reverse MMP1 assay” and giving a positive readout in the “reverse collagen degradation assay” are tested in the LPS/TNFα-induced IL8 assay as follows: 192 target KD viruses are arrayed in 96 well plates (“Hit plates”) such that every plate contained 60 target viruses along with 20 negative control viruses. Day 1, SFs (passage 9 to 12) are seeded in 96 well plates at a density of 3000 cells per well in complete synovial growth medium (Cell Applications). One day later, the cells are infected with two amounts (6 or 12 μl) of the target KD viruses arrayed in 96 well plates as indicated above. The cells are then incubated for 5 days before the activation step, which involves the replacement, in every well, of the growth medium by 150 μl of DMEM supplemented with 10% Fetal bovine serum (heat inactivated) and the trigger (2 ng/ml recombinant human TNFα or 1 μg/ml LPS). 48 hrs after the activation step, 80 μl of the supernatant is collected and a dilution from this is used for the IL-8 ELISA as described for the experiment depicted in
Data are analysed as follows: the 96 well plates containing the KD viruses designed to reduce the expression of the targets also contained 20 negative controls. The percentage inhibition of IL8 expression is calculated as percentage relative to the negative controls as follows: First, the background signal of the ELISA (in the absence of IL8) is subtracted from all values for all samples. Then the following formula is applied for every plate: % inhibition=[100×(((Average value all negative controls)−value Target sample)/(Average value all negative controls))]. All the Target KD viruses are ranked depending on their performance in the TNFα and LPS induced IL8 assay. 10% of the target KD viruses giving the strongest inhibition of LPS-induced IL8 are considered less preferred as well as 5% of the target KD viruses giving rise to the strongest increase of the TNFα-induced IL8 expression by RA SFs. As such, 40 out of the 192 Target KD viruses tested in this assay are considered to be less preferred. Further exclusion criteria used to define the present invention with more particularity are described below.
The TARGETS identified in this invention represent the basis for the identification of small molecule inhibitors developed for the treatment of RA. As such, the testing of such new candidate RA therapies in experimental models of arthritis is required before running experiments in human. The collagen-induced arthritis model in rat or mice is generally used as experimental model of arthritis. Consequently, targets, for which no ortholog can be found in rat or mice, are less preferred. Analysis of the 152 targets (identified through the experimental cascade (the “reverse MMP1” primary assay, the “reverse collagen degradation” secondary assay and the “TNFα/LPS IL8 induction assay”) revealed that 27 had no ortholog in rat or mice, leaving only 125 preferred targets. Further exclusion criteria involved the following in silico analyses:
“Drugability”. Targets were excluded if it could be determined that the development of a small molecule inhibitor would be predicted to be the least successful within a short timeframe. This analysis involved the assessment of the general drugability of the gene class to which a a certain Target belongs based on pharmacology precedents. In addition, the existence of assays allowing the discovery of small molecule inhibitors of the Targets is evaluated. We found assays available for 69 out of the 125 Targets subjected to this analysis.
“Risk profile”. Target genes for which the corresponding “knock-out mice” phenotype is diseased or lethal are considered as having lower priority, as inhibition of the product of these genes by means of a small molecule is expected to cause part of this phenotype. The Targets that play an important role in basal metabolic functions of the cells or of the organism are also given lower priority. The risk profile is considered high for 18 out of the 69 targets analysed.
“Disease relevance.” Targets that are already linked to inflammatory processes or autoimmune processes are considered as more preferred.
The forgoing set of experiments and analyses permitted the narrowing of the present set of 16 most preferred TARGETs from the list of 323 targets.
Expression levels for certain identified targets are determined in at least two different isolates of primary human synovial fibroblasts.
The RASFs isolates are obtained as cryo-preserved passage 2 cells from Cell Applications Inc. (Cat. No. 404-05). These cells are cultured and propagated in DMEM (Invitrogen) supplemented with 10% (v/v) heat-inactivated FBS (ICN) and 1× Pen/Strep (Invitrogen). For expression analysis, cells are cultured to passage 11.
For RNA preparation, the primary human synovial fibroblasts are seeded in 10-cm Petri dishes (500,000 cells/dish) in 6-well plates. After overnight incubation, medium is refreshed with 6 ml of M199 medium supplemented with 1% (v/v) heat-inactivated FBS containing 1× Pen/Strep. 24 hours later, total RNA is extracted using the “SV Total RNA Isolation kit” (Promega).
The concentration of RNA in each sample is fluorimetrically quantified using the “Ribogreen RNA quantitation kit” (Molecular Probes). A similar amount of RNA from each preparation is reverse transcribed into first strand cDNA with the “Taqman reverse transcription kit” from Applied Biosystems. Briefly, 40 ng RNA is included per 201 μl reaction mix containing 50 pmol of random hexamers, 10 U Rnase inhibitor, 25 U Multiscribe reverse transcriptase, 5 mM MgCl2 and 0.5 mM of each dNTP. The reaction mixture is incubated at 25° C. for 10 minutes, followed by 30 minutes incubation at 48° C. and heat inactivation (5 minutes 95° C.) of the reverse transcriptase in a thermocycler (Dyad, M J Research). Reactions are immediately chilled to 4° C. at the end of the program. To avoid multiple freeze/thaw cycles of the obtained cDNA, the different samples are pooled in 96-well plates, aliquoted and stored at −20° C.
Real-time PCR reactions are performed and monitored using the “ABI PRISM 7000 Sequence Detection System Instrument” (Applied Biosystems). Pre-designed, gene-specific Taqman probe and primer sets for quantitative gene expression are purchased from Applied Biosystems as part of the “Assays on Demand” Gene expression products. These commercially available kits are quality checked by the supplier and allow quantitative determination of the amount of target cDNA in the sample. The “Assays on Demand” gene expression products are used according to the protocol delivered by the supplier. The PCR mixture consisted of 1× “Taqman Universal PCR Mastermix no AmpErase UNG” and IX “Taqman Gene Expression Assay on Demand mix” and 5 ul of the retro-transcription reaction product (1-100 ng of RNA converted into cDNA) in a total volume of 25 ul. After an initial denaturation step at 95° C. for 10 minutes, the cDNA products are amplified with 40 cycles consisting of 95° C. for 15 sec, and 60° C. for 1 minutes To normalize for variability in the initial quantities of cDNA between different samples, amplification reactions with the same cDNA are performed for the housekeeping gene P-actin using the predeveloped β-actin “Assays on demand” primer set and Taqman probe mix and “Taqman Universal PCR Mastermix” (all Applied Biosystems) according to the manufacturer's instructions. To identify any contamination resulting from residual genomic DNA, real-time PCR reactions with product from a control (—RT) reverse transcription reaction that is performed under the same conditions but without the addition of the reverse transcriptase are included for each sample. Threshold cycle values (Ct), for example, the cycle number at which the amount of amplified gene of interest reached a fixed threshold are determined for each sample. For each sample, the ΔCt value is determined by substracting the Ct value of the endogenous control (β-actin) from the Ct value obtained for the target gene. A gene is considered as expressed in primary human SFs if the ΔCt value obtained for this hit is lower than 13.3 in at least one of the available 2 synovial isolates, activated or not. Genes with a ΔCt value below 9.9 are considered highly expressed in RASFs. The results of the expression profiling experiments are summarized in Table 5. The ΔCt value relative to β-actin obtained for various targets in 2 isolates of untriggered SFs are given in this Table 5.
As described above, the screening of the SilenceSelect collection identifies a set of Ad5-siRNAs that exhibit the capacity to reduce the cytokine-induced RASF MMP1 expression. A subset of these viruses is tested in the “reverse MMP1 assay” at various concentrations in a dose response experiment.
SFs (passage 9 to 10) are seeded in 96 well plates at a density of 3000 cells/well in complete synovial growth medium (Cell Applications). One day later, the cells are infected with increasing amounts (3, 7.5, 12, or 15 μl) of the Ad5-MMP1_v10_KD (positive control) or Ad5-Luciferase_v13_KD (negative control). The virus load is corrected by addition of the neutral virus Ad5-Luciferase_v13_KD to bring the final virus volume on the cells to 15 μl in every well. This correction guarantees that the effects observed do not result from differences in the virus load applied to the cells. The cells are then incubated for 5 days before the activation step. This step involves the replacement, in every well, of the growth medium by 75 μl of M199 medium supplemented with 25 μl of “complex trigger”. 48 hours after the activation step, the supernatant is collected and subjected to the MMP1 ELISA as described previously.
This experiment clearly demonstrates that the application of increased amounts of Ad5-siRNA to RASFs will lead to an increased reduction of the expression of the target in the RASFs. In this case, applying increasing amounts of Ad5-MMP1_v10_KD to the cells leads to higher reduction in MMP1 protein expression by the cells. (
The Ad-siRNAs used in these dose response experiments are generated according to the procedure described in WO03/020931. The target sequences of these genes, on which the siRNAs are designed and used to generate the recombinant adenoviruses, are listed in Table 1. The Ad5-siRNA efficacy in the MMP1 ELISA is tested as described above with respect to the positive and negative controls with the only difference being that multiple Ad-siRNAs targeting the genes listed in Table 1 are used to infect the cells. The viruses used to infect the cells are shown on
The data shown in
We conclude, from this experiment, that these genes represent valuable drug targets that are shown to modulate MMP1 expression in SFs, and that the inhibition of the activity of the protein product of these genes by an inhibitory agent, such as a small molecule compound, is expected to reduce “complex cytokine” induced MMP1 expression in the “reverse MMP1 assay”. We also believe that the inhibition of the activity of the protein products of these genes by such agents would also reduce the joint degradation observed in RA patients.
Table 1 lists multiple KD sequences produced for every TARGET gene identified in Table 1. Different Ad-siRNAs are generated from different target sequences within the TARGET mRNA. Although some of the Ad-siRNA viruses exhibit efficacy in the “reverse MMP1 assay,” we observe that some of these Ad-siRNA viruses do not exhibit efficacy in the “reverse MMP1 assay”. It should be understood, however, that not all shRNAs are as efficient in reducing target expression. There may be many cause of this difference in knockdown efficacy, including the physical availability of the target RNA to the siRNA degradation machinery (for example, in a three dimensional folding of any TARGET mRNA which is in close proximity with and/or binding to other cellular proteins, only a fraction of the mRNA may be “exposed” so as to provide a binding site for siRNA association), the potency of the target protein, degradation processes affecting the particular shRNA itself, and others. More particularly, the low efficacy of certain Ad-siRNAs in the “reverse MMP1 assay” may be explained by the level of reduction in target gene expression required to reduce cytokine-induced MMP1 expression by the cells. Some targets may require only 50% reduction to shut down the MMP1 pathway, while others may require 90% to achieve the same effect. Some targets may participate in metabolic pathways that compensate for target depletion, while others do not. As a consequence, testing these viruses at higher doses might lead to higher efficacy in the reverse MMP1 assay.
Certain MMP subtypes (for example, MMP1, MMP13) are collagenases and have the remarkable capacity of degrading native collagen. Native collagen is organized in stable fibrils that are quite resistant to proteolytic events. As such, the degradation of native collagen can be used to monitor not only MMP1 but also the complete complement of collagenases produced by RASFs. Described herein is an assay developed to detect the cytokine-induced degradation of native collagen in the supernatant of RASF cultures.
“Miniaturized Collagen Type I Degradation Assay” protocol: (Reagents are from Chondrex, Redmond, Wash. (Collagenase assay kit) unless specified differently). A 96 well plate (V-bottom, Greiner) is filled with 9 μl of solution B and 1 μl of trypsin solution per well. 10 μl of sample (RASF supernatant) is added per well, followed by incubation for 15 minutes at 34° C. After incubation, 1 μl SBTI is added. 20 μl of FITC-Collagen mix (10 μl FITC-labeled collagen type I+10 μl solution A) are added to the activated sample followed by incubation for 24 hours at 34° C. 1 μl of 1,10 Phenantroline (Sigma) is added to the reaction mixture. One μl of enhancer solution (elastase) is added, followed by incubation for 30 minutes at 34° C. When the reaction mixture is at room temperature, 40 μl extraction buffer are added and the plate is sealed (Nunc seals) and vortexed. After centrifugation for 25 minutes at 4000 rpm (Beckman centrifuge), 50 μl of the supernatant are transferred into a black F-bottom plate (Greiner) and fluorescence is measured on a Fluostar reader (BMG), 480 nm excitation wavelength, 520 nm emission wavelength).
Ad5-siRNA efficacy in the “miniaturized collagen type I degradation assay” is tested as follows: SFs (passage 9 to 10) are seeded in 96 well plates at a density of 3000 cells/well in complete synovial growth medium (Cell Applications). One day later, the cells are infected with 5 or 10 μl of the Ad-siRNAs indicated on
In similar experiments (
To better understand the profile of the TARGETS (identified according to the experiments described in previous examples), and to probe for the specificity of TARGET expression reduction effects, IL8, another inflammation marker different from MMP1, is used in the following example. This example measures the effect of TARGET expression reduction in RA SFs on TNFα-induced IL8 expression. IL8 expression is increased by TNFα, and plays a role in inflammatory events. Additionally, a small molecule inhibitor of the IL8 receptor has been shown to have efficacy in an animal model of arthritis (See Weidner-Wells MA et al., Bioorg Med Chem Lett. (2004)14:4307-11, “Synthesis and structure-activity relationships of 3,5-diarylisoxazoles and 3,5-diaryl-1,2,4-oxadiazoles, novel classes of small molecule interleukin-8 (IL-8) receptor antagonists. As such, achieving inhibition of IL8 expression is a desired feature for an RA therapeutic.
“IL-8 assay” protocol: SFs (passage 9 to 12) are seeded in 96 well plates at a density of 3000 cells/well in complete synovial growth medium (Cell Applications). One day later, the cells are infected with two amounts (6 or 12 μl) of the KD viruses. The cells are then incubated for 5 days before the activation step. The activation step involves the replacement, in every well, of the growth medium by 150 μl of DMEM supplemented with 10% Fetal Bovine serum (heat inactivated) and the trigger (2 ng/ml recombinant human TNFalpha). 48 hours after the activation step, 80 μl of the supernatant is collected and diluted for use in the IL-8 ELISA described below. For the samples triggered with TNFalpha, a 40 fold dilution is made in PBS+1% BSA. 35 μl from these dilutions are added to the IL-8 ELISA plates.
White Lumitrac 600 384 well plates (Greiner) are coated with 0.5 μg/ml anti-IL8 antibody MAB208(R&D). The antibody is diluted in 1×PBS (Gibco). After overnight incubation at 4° C., plates are washed once with 1× PBST (80 g NaCl, 2 g KCl (Sigma), 11.5 g Na2HPO4.7H2O and 2 g KH2PO4 in 10 L milliQ; pH 7.4=10× PBS solution+0.05% tween-20 (sigma)), once with PBS 1×, and blocked with 80 μl blocking buffer (1% BSA+5% sucrose+0.05% NaN3). One day later, the blocking buffer is removed from the ELISA plates by inverting the plate and tapping it on an absorbent paper. The plate is washed with 90 μl PBST and 90 μl PBS 1×. Immediately thereafter, the plate is further processed and 35 μl of the diluted supernatant is added. After overnight incubation at 4° C., the plates are washed once with PBST and once with PBS (as described above) and incubated with 35 μl/well biotinylated anti-IL 8 antibody solution BAF208 (R&D) 50 ng/ml in PBS 1×+1% BSA. After 2 hours of incubation at room temperature, plates are washed as described above and incubated with 50 μl/well streptavidin-HRP conjugate (Biosource). Streptavidin-HRP conjugate is diluted 1/2000 times in PBS 1×+1% BSA. After 45 minutes, plates are washed as described above and incubated for 5 minutes with 50 μl/well BM Chem ELISA Substrate (Roche). Readout is performed on the Luminoscan Ascent Luminometer (Labsystems) with an integration time of 100 msec.
Twenty negative controls are included in the 96 well plates. The percentage inhibition of IL8 expression is calculated as follows. First, the background signal of the ELISA (in the absence of IL8) is substracted from all values for all samples. Then the following formula is applied: % inhibition=[100×(((Average value all negative controls)−value TARGET sample)/(Average value all negative controls))]. From the results depicted in
P: positive response in the assay
SP: Strong positive response in the assay
NT: not tested
N: negative response in the assay
*Expression in primary RASFs: Genes with DCt <13 are considered expressed (P), genes with DCt >9.9 are considered strongly expressed (SP)
**Inhibition of cytokine mixture induced MMP1 expression by RASFs >50% reduction in MMP1 expression is considered a strong positive response in the assay
***Inhibition of cytokine induced collagen degradation by RASFs >50% reduction in cytokine induced collagen degradation is considered a strong positive response in the assay
****Inhibition of TNFα induced IL-8 expression by RASFs >20% inhibition of TNFα induced IL-8 expression is considered a significant response in the assay (P), >50 inhibition is considered a strong positive response in the assay
This application claims priority to U.S. Provisional Application No. 60/619,384, filed Oct. 15, 2004, the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60619384 | Oct 2004 | US |
