The present invention relates to a modulatory substance of the tumor immune microenvironment, and preventive, diagnostic and therapeutic utilization of the same. More specifically, the present invention relates to an inhibitory substance of the function of TCTP (translationally controlled tumor protein), a drug or a composition for treating cancer, comprising the inhibitory substance, and utilization of the inhibitory substance in the prevention, diagnosis and/or treatment of cancer.
Immune response mechanism against cancer has been discussed for a long period of time, and various study reports have been made. As a result of recent studies, the mechanism thereof, etc. has been finally understood, and the “immunotherapy of cancer” has attracted attention.
At present, main immunotherapies actually used in cancer therapy may include “checkpoint inhibitor antibody therapy” and “CAR-T cell therapy.” Regarding the effects of these immunotherapies, it can be confirmed that the immunotherapies exhibit certain effects on certain types of cancers. However, under current circumstances, it cannot be said that these immunotherapies are sufficient also for the treatment of many other cancers.
Both of the above-described two therapies are intended to perform cancer therapy by activation of lymphocytes (that attack cancer). On the other hand, in living bodies, a mechanism of suppressing an immune function that attacks cancer cells, which is referred to as a “tumor immune microenvironment (TIME),” has been known (Non Patent Literature 1 and Non Patent Literature 2). The tumor immune microenvironment is also called a “cradle of cancer,” and a mechanism of suppressing an immune response to cancer is present in the tumor immune microenvironment. Thus, it has been known that an environment advantageous for proliferation of cancer cells can be created in the tumor immune microenvironment. As such, it is expected that elucidation of the interaction between cancer cells and immune cells and the interaction between related molecules in TIME will lead to the development of a novel immunotherapy.
By the way, cells that play an important role in the above-described immunosuppressive function associated with progression of tumor may be, for example, myeloid-derived suppressor cells (MDSCs). MDSC is a population of progenitor cells that are present in the bone marrow and each have a different differentiation degree, before being differentiated into granulocytes, dendritic cells, macrophages, etc. Among cell populations constituting MDSCs, in particular, two types of cell populations have been identified in mice and humans, and have attracted attention. One of these two types of cells are polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) having phenotypes and morphological features that are similar to those of neutrophils. The other type of cells are monocytic myeloid-derived suppressor cells (M-MDSCs) known to be differentiated into tumor-associated macrophages (TAMs) (Non Patent Literature 3). Regarding the relationship between MDSCs and cancer, it has been reported that, in malignant tumors, the expression level of MDSCs increases and the MDSCs accumulates in TIME, and that the MDSCs show a direct correlation with clinical cancer stage, the amount of metastatic tumor, and the prognosis of cancer. Since MDSCs actually suppress the activation and/or proliferation of lymphocytes (Non Patent Literature 4), it is conceived that the MDSCs play a role in promoting progression of tumor.
However, the mechanism of accumulation of MDSCs in TIME has not yet been elucidated.
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Considering the aforementioned circumstances, it is an object of the present invention to identify a modulatory substance of the tumor immune microenvironment and to provide a therapeutic utilization method involving inhibition by the modulatory sub stance.
It has been known that a majority of tumor cells die during the proliferation thereof due to necrosis as a main cause, as a result of mutagenesis or changes in the surrounding environment (for example, hypoxia, etc.) (Non Patent Literature 12). The present inventors have made a working hypothesis that molecules released from dead (which hereinafter means “necrotic”) tumor cells (hereinafter also referred to as “dead tumor cells”) function as immunomodulators of MDSCs in TIME, and the present inventors have then conducted intensive studies regarding the working hypothesis. As a result, the present inventors have discovered for the first time that a translationally controlled tumor protein (hereinafter referred to as “TCTP”) released from deal tumor cells is a novel immunomodulator that controls the functions and/or dynamics of MDSCs in TIME.
Specifically, the present inventors have clarified that extracellular TCTP mainly acts on M-MDSCs, so that it induces the expression of a CXCL1 family chemokine. The CXCL1 family chemokine induces PMN-MDSCs to TIME, so that the TIME becomes a highly immunosuppressive state. The present inventors have clarified that induction of PMN-MDSCs to TIME is inhibited by administration of an anti-TCTP monoclonal antibody or a TCTP function inhibitory substance, and that proliferation of tumors is thereby suppressed. The present invention have overcome an unsolved problem regarding how the tumor constructs and controls TIME, by identification of TCTP and clarification of a novel function thereof, and then, have developed a method for inhibiting TCTP, thereby completing the present invention.
The present invention includes the following (1) to (13).
(1) An inhibitor of the accumulation of myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment (TIME), wherein the inhibitor comprises, an active ingredient, a substance that suppresses or inhibits the function of an immunomodulator released from dead tumor cells.
(2) The inhibitor according to the above (1), wherein the myeloid-derived suppressor cells are polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs).
(3) The inhibitor according to the above (1) or (2), wherein the immunomodulator is TCTP (translationally controlled tumor protein).
(4) The inhibitor according to the above (3), wherein the substance that suppresses or inhibits the function of TCTP is an antibody.
(5) The inhibitor according to the above (3), wherein the substance that suppresses or inhibits the function of TCTP is dihydroartemisinin (DHA).
(6) A therapeutic drug or composition for cancer, comprising, as an active ingredient, the inhibitor according to any one of the above (1) to (5).
(7) The therapeutic drug or composition according to the above (6), wherein the cancer is colorectal cancer, malignant melanoma, or fibrosarcoma.
(8) A method for diagnosing or auxiliarily diagnosing cancer, comprising measuring the amount of TCTP mRNA or TCTP protein that is present in a sample derived from a subject.
(9) The method according to the above (8), wherein the sample is blood or tissue.
(10) An antibody, which is characterized in that the amino acid sequences of CDRs (complementarity determining regions) 1 to 3 satisfy any of the following (A), (B) or (C), or an antigen-binding fragment thereof:
(A) the CDRs have:
It is to be noted that the symbol “−” (“to”) means a numerical range including the values located right and left of the symbol.
According to the present invention, a novel therapeutic agent for cancer and a novel method for treating cancer are provided.
Hereinafter, the embodiments of the present invention will be described.
A first embodiment of the present invention relates to an inhibitor of the accumulation of myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment (TIME), wherein the inhibitor comprises, an active ingredient, a substance that suppresses or inhibits the function of an immunomodulator released from dead tumor cells (hereinafter also referred to as “the inhibitor according to the present embodiment”).
Herein, the tumor immune microenvironment (hereinafter also referred to as “TIME”) means a site of interaction between cancer cells and non-cancer cells mainly including immune cells, and the tumor immune microenvironment is defined to be a microenvironment present in cancer, which comprises an environment advantageous for the survival of cancer, including advanced immunosuppression as a typical example (Non Patent Literature 1). Myeloid-derived suppressor cells (which are also referred to as “MDSCs”) are immature myeloid cells appearing in infectious disease or chronic inflammation such as cancer, and having strong immunosuppressive activity. Monocytic myeloid-derived suppressor cells (which are also referred to as “M-MDSCs”) and polymorphonuclear myeloid-derived suppressor cells (which are also referred to as “PMN-MDSCs”) constitute principal subpopulations, and these two types of cells are similar to monocytes and neutrophils, respectively, in terms of forms and cell surface markers (Non Patent Literature 3). Accumulation of MDSCs in TIME means that MDSCs such as PMN-MDSCs are located in the TIME or around the TIME.
Herein, the immunomodulator means a factor that promotes or suppresses immune response and influences on the function of the immune system.
The present inventors have found that, when TCTP (a translationally controlled tumor protein) as a molecule released from dead tumor cells acts on blood cells present in the TIME, cytokines such as CXCL1 and CXCL2 are significantly released from, in particular, M-MDSCs, among those blood cells. Moreover, the present inventors have also found that CXCL1 and CXCL2 induce PMN-MDSCs into or around the tumor immune microenvironment, mediated by CXCR2 receptors present on the PMN-MDSCs. It has been known that the PMN-MDSCs induced into or around the tumor immune microenvironment suppress the attack of immune cells such as T cells or NK cells against cancer cells (Non Patent Literature 3). According to the present analysis, it has been newly clarified that the antitumor activity of immune cells is suppressed by accumulation of PMN-MDSCs in TIME through the aforementioned TCTP-(M-MDSC)-CXCL1/2-(PMN-MDSC) pathway, so that tumor proliferation can be promoted. Accordingly, if accumulation of MDSCs (for example, PMN-MDSCs) in the TIME were inhibited, accumulation or activation of T cells, NK cells, etc. could be promoted, and as a result, tumor proliferation could be inhibited or suppressed.
In order to inhibit accumulation of PMN-MDSCs in the TIME, for example, it is conceived to block the TCTP-(M-MDSC)-CXCL1/2-(PMN-MDSC) pathway. The method of blocking this pathway may be, for example, the use of a substance that suppresses or inhibits the function of TCTP (regarding human TCTP, NCBI Accession No.; cDNA sequence: CCDS9397.1, and amino acid sequence: NP_003286.1). Herein, the function of TCTP may be, for example, the function of TCTP to bind to a receptor thereof (e.g. TLR2) and to induce the release of cytokines (e.g. CXCL1/2) from cells (e.g. M-MDSCs, etc.).
Examples of the substance that suppresses or inhibits the function of TCTP may include, but are not particularly limited to: antibodies, peptide aptamers, and the like that suppress or inhibit the function of TCTP; substances that decompose TCTP or induce decomposition of TCTP, such as, for example, dihydroartemisinin (DHA) and Sertraline; and substances that suppress or inhibit the expression of TCTP, such as, for example, siRNA and miRNA. Further examples of the substance that suppresses or inhibits the function of TCTP may also include substances that inhibit the binding of TCTP to a receptor thereof (TLR2), such as, for example, a TLR2 antagonist. This inhibitory substance may be a substance that interacts with TCTP or a receptor thereof (TLR2), or decomposes any one of them.
The inhibitor according to the present embodiment may comprise the above-described substance that suppresses or inhibits the function of TCTP.
A second embodiment of the present invention relates to an antibody that suppresses or inhibits the function of TCTP (hereinafter also referred to as “the anti-TCTP antibody according to the present embodiment”).
The “antibody” used in the present description is not particularly limited in terms of a preparation method thereof and a structure thereof, and examples of the present antibody may include all “antibodies” that each bind to a desired antigen based on desired properties, such as, for example, a monoclonal antibody, a polyclonal antibody, or a nanoantibody.
When the anti-TCTP antibody according to the present embodiment is a polyclonal antibody, the anti-TCTP antibody can be prepared, for example, by injecting a mixture of an antigen and an adjuvant into an animal to be immunized (which, for example, includes, but is not limited to, a rabbit, a goat, sheep, a chicken, a Guinea pig, a mouse, a rat, a pig, etc.). In general, an antigen and/or an adjuvant are injected into the subcutis or abdominal cavity of such an animal to be immunized several times. Examples of the adjuvant may include, but are not limited to, complete Freund and monophosphoryl lipid A synthesis-trehalose dicholinemicolate (MPL-TMD). After immunization with the antigen, the anti-TCTP antibody can be purified from the serum derived from the immunized animal by a conventional method (for example, a method using Sepharose that carries Protein A, etc.).
On the other hand, when the anti-TCTP antibody according to the present embodiment is a monoclonal antibody, the anti-TCTP antibody can be produced, for example, as follows. Besides, the term “monoclonal” is used in the present description to suggest the properties of an antibody obtained from a population of substantially uniform antibodies (i.e. an antibody population, in which the amino acid sequences of heavy chains and light chains constituting the antibodies are identical to one another), and thus, it should not be restrictively interpreted that the antibody is produced by a specific method (e.g. a hybridoma method, etc.).
Examples of the method of producing a monoclonal antibody may include a hybridoma method (Kohler and Milstein, Nature 256, 495-497, 1975) and a recombination method (U.S. Pat. No. 4,816,567). Otherwise, the anti-TCTP antibody according to the present embodiment may be isolated from a phage antibody library (for example, Clackson et al., Nature 352, 624-628, 1991; Marks et al., J. Mol. Biol. 222, 581-597, 1991; etc.) and the like. More specifically, when a monoclonal antibody is prepared by applying a hybridoma method, the preparation method includes, for example, the following 4 steps: (i) immunizing an animal to be immunized with an antigen, (ii) recovering monoclonal antibody-secreting (or potentially secreting) lymphocytes, (iii) fusing the lymphocytes with immortalized cells, and (iv) selecting cells that secrete a desired monoclonal antibody. Examples of the animal to be immunized that can be selected herein may include a mouse, a rat, a Guinea pig, a hamster, and a rabbit. After completion of the immunization, in order to establish hybridoma cells, lymphocytes obtained from a host animal are fused with an immortalized cell line, using a fusion agent such as polyethylene glycol, or an electrical fusion method. As fusion cells, for example, a rat or mouse myeloma cell line is used. After completion of the cell fusion, the cells are allowed to grow in a suitable medium containing a substrate that inhibits the growth or survival of unfused lymphocytes and immortalized cell line. According to an ordinary technique, parent cells that lack the enzyme, hypoxanthine-guanine phosphoribosyl transferase (HGPRT or HPRT), are used. In this case, aminopterin is added to a medium that inhibits HGPRT-deficient cells and accepts the growth of hybridomas (i.e. HAT medium). From the thus obtained hybridomas, hybridomas generating desired antibodies are selected, and thereafter, a monoclonal antibody of interest can be obtained from a medium in which the selected hybridomas grow, according to an ordinary method.
The thus prepared hybridomas are cultured in vitro, or are cultured in vivo in the ascites fluid of a mouse, a rat, a Guinea pig, a hamster, etc., and an antibody of interest can be then prepared from the culture supernatant, or from the ascites fluid.
Nanoantibody is a polypeptide consisting of a variable region of an antibody heavy chain (i.e. a variable domain of the heavy chain of heavy chain antibody (VHH)). In general, an antibody of a human or the like is composed of heavy and light chains. However, animals of family Camelidae, such as llamas, alpacas and camels, produce single-chain antibodies (heavy chain antibodies) consisting only of heavy chains. Such a heavy chain antibody can recognize a target antigen and can bind thereto, as in the case of a common antibody consisting of heavy and light chains. The variable region of a heavy chain antibody is the smallest unit that has a binding affinity to an antigen, and this variable region fragment is called a “nanoantibody.” Nanoantibodies have high heat resistance, digestion resistance, and room temperature stability, and can be easily prepared in large quantities by a genetic engineering technique.
A nanoantibody can be produced, for example, as follows. An animal of family Camelidae is immunized with an antigen, and the presence or absence of an antibody of interest is then detected from the collected serum. Thereafter, cDNA is prepared from RNA derived from the peripheral blood lymphocytes of an immunized animal, in which a desired antibody titer is detected. A DNA fragment encoding VHH is amplified from the obtained cDNA, and the amplified DNA fragment is then inserted into a phagemid to prepare a VHH phagemid library. A desired nanoantibody can be prepared from the prepared VHH phagemid library through several screenings.
The anti-TCTP antibody according to the present embodiment may be a genetically engineered antibody. Such a genetically engineered antibody is not limited, and examples thereof may include a humanized antibody, and a chimeric antibody with a human antibody. The chimeric antibody is, for example, an antibody, in which a variable region derived from a different animal species is linked with a constant region derived from another different animal species (for example, an antibody, in which a variable region of a rat-derived antibody is bound to a constant region derived from a human) (for example, Morrison et al., Proc. Natl. Acad. Sci. U.S.A. 81, 6851-6855, 1984., etc.). The chimeric antibody can be easily constructed by genetic recombination technology.
The humanized antibody is an antibody that has a human-derived sequence in the framework region (FR) thereof and has a complementarity determining region (CDR) consisting of a sequence derived from another animal species (for example, a mouse, etc.). When such a humanized antibody is first explained using another animal species, for example, using a mouse, CDRs are transplanted from the variable regions of a mouse-derived antibody into human antibody variable regions, so that the heavy chain and light chain variable regions of the human antibody are reconstituted. Thereafter, the humanized reconstituted human antibody variable regions are ligated to humanized antibody constant regions, so that a humanized antibody can be produced. The method for producing such a humanized antibody is publicly known in the present technical field (e.g. Queen et al., Proc. Natl. Acad. Sci. USA, 86, 10029-10033, 1989., etc.).
The antigen-binding fragment of the anti-TCTP antibody according to the present embodiment is a partial region of the anti-TCTP antibody according to the present embodiment, which is an antibody fragment that binds to TCTP. Examples of such an antigen-binding fragment may include Fab, Fab′, F(ab′)2, Fv (a variable fragment of an antibody), a single chain antibody (a heavy chain, a light chain, a heavy chain variable region, a light chain variable region, a nanoantibody, etc.), scFv (single chain Fv), a diabody (an scFv dimer), dsFv (disulfide-stabilized Fv), and a peptide comprising the CDR of the anti-TCTP antibody according to the present embodiment, at least, as a part thereof.
Fab is an antibody fragment having antigen-binding activity, in which about a half of the N-terminal side of a heavy chain and a light chain as a whole are bound to each other via a disulfide bond, among fragments obtained by treating an antibody molecule with the proteolytic enzyme papain. Such Fab can be produced by treating an antibody molecule with papain to obtain a fragment, and also, for example, by constructing a suitable expression vector into which DNA encoding Fab is inserted, then introducing this vector into suitable host cells (e.g. mammalian cells such as CHO cells, yeast cells, insect cells, etc.), and then allowing Fab to express in the cells.
F(ab′)2 is an antibody fragment having antigen-binding activity, which is slightly larger than a fragment obtained by treating an antibody molecule with the proteolytic enzyme pepsin, in which Fab is bound via a disulfide bond in the hinge region. Such F(ab′)2 can be produced by treating an antibody molecule with pepsin to obtain a fragment, or via a thioether bond or a disulfide bond, or further, by a genetic engineering technique, as in the case of Fab.
Fab′ is an antibody fragment having antigen-binding activity, in which the disulfide bond in the hinge region of the above-described F(ab′)2 is cleaved. Such Fab′ can also be produced by a genetic engineering technique, as in the case of Fab.
scFv is a VH-linker-VL or VL-linker-VH polypeptide, in which one heavy chain variable region (VH) and one light chain variable region (VL) are linked to each other using a suitable peptide linker, and it is an antibody fragment having antigen-binding activity. Such ScFv can be produced by obtaining cDNAs encoding the heavy and light chain variable regions of an antibody, and then performing a genetic engineering technique.
Diabody is an antibody fragment having a divalent antigen-binding activity, in which scFv is dimerized. The divalent antigen-binding activity may be an identical antigen-binding activity, or one of them may be a different antigen-binding activity. Such a diabody can be produced by obtaining cDNAs encoding the heavy chain and light chain variable regions of an antibody, then constructing cDNA encoding scFv, in which the heavy chain variable region and the light chain variable region are linked to each other by a peptide linker, and then performing a genetic engineering technique.
DsFv refers to polypeptides, in which one amino acid residue in each of the heavy chain variable region and the light chain variable region is replaced with a cysteine residue, which are bound to each other via a disulfide bond between the cysteine residues. The amino acid residue to be replaced with the cysteine residue can be selected based on the prediction of the three-dimensional structure of the antibody. Such dsFv can be produced by obtaining cDNAs encoding the heavy chain and light chain variable regions of an antibody, then constructing DNA encoding the dsFv, and then performing a genetic engineering technique.
A peptide comprising a CDR is configured to comprise at least one region of the CDRs (CDR1 to 3) of a heavy or a light chain. A plurality of peptides each comprising a CDR can be bound to one another, directly or via a suitable peptide linker. Such a peptide comprising a CDR can be produced by constructing DNA encoding the CDR of the heavy chain or light chain of an antibody, and inserting the constructed DNA into an expression vector. Herein, the type of the vector is not particularly limited, and it may be appropriately selected, depending on the types of host cells into which the vector is to be introduced, etc. Thereafter, the peptide comprising a CDR can be produced by introducing the expression vector comprising the DNA into suitable host cells (e.g. mammalian cells such as CHO cells, yeast cells, insect cells, etc.) for allowing it to express as an antibody. Alternatively, the peptide comprising a CDR can also be produced by a chemical synthesis method such as an Fmoc method (fluorenylmethyloxycarbonyl method) and a tBoc method (t-butyloxycarbonyl method).
In general, in the case of a human antibody (a complete human antibody), a hypervariable region that is the antigen binding site of a V region, other parts of the V region, and a constant region have the same structures as those of the antibody of a human. Such a human antibody can be easily produced by a person skilled in the art according to a known technique. The human antibody can be obtained by, for example, a method using a human antibody-producing mouse having a human chromosome fragment containing the H chain and L chain genes of the human antibody (e.g. Tomizuka et al., Proc. Natl. Acad. Sci. USA, 97, 722-727, 2000., etc.) or a method of obtaining a human antibody derived from a phage display selected from a human antibody library (see, for example, Siriwardena et al., Opthalmology, (2002) 109 (3), 427-431, etc.).
A multispecific antibody can be constructed using the antigen-binding fragment of the anti-TCTP antibody according to the present embodiment. Multispecificity means that an antibody has binding specificity to two or more antigens, and may be, for example, the form of a protein containing a monoclonal antibody having binding specificity to two or more antigens or an antigen-binding fragment thereof. Such multi specificity is achieved by a person skilled in the art according to a known technique. As methods of constructing multispecificity, there have been developed multiple methods, which are classified into a technique of constructing an asymmetric IgG, in which two different types of antibody heavy chain molecules are subjected to protein engineering operations so that they form a heterodimer, and a technique of ligating to each other, antigen-binding fragments each having a low molecular weight, which are obtained from an antibody, or ligating such an antigen-binding fragment to another antibody molecule. As an example of a specific construction method, the following publication can be, for example, referred to: Kontermann et al., Drug Discovery Today, 20, 838-847, 2015.
Examples of the anti-TCTP antibody according to the present embodiment and an antigen-binding fragment thereof may include antibodies, which are characterized in that the amino acid sequences of CDRs (complementarity determining regions) 1 to 3 satisfy any of the following (A), (B) or (C), and antigen-binding fragments thereof.
(A) CDRs of 55F3 antibody have:
Moreover, the anti-TCTP antibody according to the present embodiment and an antigen-binding fragment include: an antibody comprising any of heavy chain variable regions comprising the amino acid sequence as set forth in SEQ ID NO: 19, SEQ ID NO: 20, or SEQ ID NO: 21, an antibody comprising any of light chain variable regions comprising the amino acid sequence as set forth in SEQ ID NO: 22, SEQ ID NO: 23, or SEQ ID NO: 24, and antigen-binding fragments thereof; and an antibody consisting of an amino acid sequence having an amino acid sequence identity of about 70% or more, preferably, about 80% or more, about 81% or more, about 82% or more, about 83% or more, about 84% or more, about 85% or more, about 86% or more, about 87% or more, about 88% or more, or about 89% or more, more preferably, about 90% or more, about 91% or more, about 92% or more, about 93% or more, about 94% or more, about 95% or more, about 96% or more, about 97% or more, or about 98% or more, and most preferably about 99% or more, to the amino acid sequence of each of a heavy chain variable region and/or a light chain variable region that constitute the aforementioned antibodies, wherein the antibody inhibits the binding of TCTP to a receptor thereof, and an antigen-binding fragment thereof.
Furthermore, the anti-TCTP antibody according to the present embodiment also includes an antibody that competitively inhibits the binding of the antibody characterized in that the amino acid sequences of CDRs (complementarity determining regions) 1 to 3 satisfy any of the above-described (A), (B) or (C), to TCTP, and that suppresses or inhibits the function of TCTP (hereinafter also referred to as “the competitive antibody according to the present embodiment”). The competitive antibody according to the present embodiment can be prepared and obtained by a competitive experiment and the like that are publicly known to a person skilled in the art. Specifically, when the binding of a first anti-TCTP antibody (the anti-TCTP antibody according to the present embodiment) to TCTP is competitively inhibited by a second anti-TCTP antibody, it is judged that the first anti-TCTP antibody and the second anti-TCTP antibody bind to a substantially identical antigen site, or that they bind to antigen sites that are extremely close to each other. When the second anti-TCTP antibody suppresses or inhibits the function of TCTP, the second anti-TCTP antibody is the competitive antibody according to the present embodiment, and is included in the anti-TCTP antibody according to the present embodiment. Besides, as a method of the above-described competitive experiment, for example, a method of using a Fab fragment or the like is generally carried out in the present technical field. Please refer to, for example, WO95/11317, WO94/07922, WO2003/064473, WO2008/118356, WO2004/046733, etc. Moreover, whether or not the second anti-TCTP antibody suppresses or inhibits the function of TCTP can be easily confirmed by the method disclosed in the after-mentioned Examples.
Further, the anti-TCTP antibody according to the present embodiment also includes an antibody that binds to a partial peptide of TCTP that is EDGVTPYMIFFKDGLEMEKC (SEQ ID NO: 25) and suppresses or inhibits the function of TCTP.
A third embodiment of the present invention relates to a therapeutic drug or composition for cancer, comprising the inhibitor of the present invention as an active ingredient (hereinafter referred to as a “therapeutic drug or the like”) (the therapeutic drug or the like according to the embodiment of the present invention).
As a therapeutic drug for cancer according to the embodiment of the present invention, the active ingredient itself (e.g. a substance that suppresses or inhibits the function of TCTP, etc.) may be administered. However, in general, the therapeutic drug for cancer according to the embodiment of the present invention is desirably administered in the form of a therapeutic composition comprising one or two or more pharmaceutical additives, as well as one or more substances serving as an active ingredient(s). The therapeutic drug or the like of the present invention may comprise, as active ingredients, a plurality of different inhibitors of the present invention. Moreover, the therapeutic drug or the like of the present invention may also comprise known components of other anticancer agents, immune checkpoint inhibitors, and the like.
The dosage forms of the therapeutic drug or the like according to the embodiment of the present invention may include tablets, capsules, granules, powder agents, syrups, suspensions, suppositories, ointments, creams, gelling agents, patches, inhalants, and injections. These preparations are produced according to ordinary methods. Liquid preparation may be dissolved or suspended in water or another suitable solvent at the time of use. In addition, tablets and granules may be coated by a publicly known method. Injections are prepared by dissolving the active ingredient in water. As necessary, the active ingredient of the injection may be dissolved in a normal saline or a glucose solution, and further, a buffer agent or a preservative may be added to such a solution.
A preparation for use in oral administration or parenteral administration is provided in any given preparation form. Examples of the preparation form that can be prepared herein may include: therapeutic drugs or compositions for use in oral administrations, having forms such as granules, fine granules, powder agents, hard capsules, soft capsules, syrups, emulsions, suspensions, or liquid agents; and therapeutic drugs or compositions for use in parenteral administrations such as intravenous administration, intermuscular administration, or subcutaneous administration, having forms such as injections, drops, transdermal absorbents, transmucosal absorbents, nasal drops, inhalants, or suppositories. Such injections or drops can be prepared as powdery dosage forms such as freeze-dried forms, and can be then used by being dissolved in an appropriate aqueous medium such as a normal saline at the time of use.
The types of pharmaceutical additives used in production of the therapeutic drug or the like according to the embodiment of the present invention, the ratio of the pharmaceutical additives to the active ingredient, or a method for producing a pharmaceutical drug or a pharmaceutical composition can be appropriately selected by a person skilled in the art, depending on the forms thereof. As such pharmaceutical additives, inorganic or organic substances, or solid or liquid substances can be used. In general, such pharmaceutical additives can be mixed in an amount from 1% by weight to 90% by weight, based on the weight of the active ingredient. Specific examples of the pharmaceutical additives may include lactose, glucose, mannit, dextrin, cyclodextrin, starch, sucrose, magnesium aluminometasilicate, synthetic aluminum silicate, sodium carboxymethyl cellulose, hydroxypropyl starch, calcium carboxymethyl cellulose, ion exchange resin, methyl cellulose, gelatin, gum Arabic, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone, polyvinyl alcohol, light anhydrous silicic acid, magnesium stearate, talc, tragacanth, bentonite, veegum, titanium oxide, sorbitan fatty acid ester, sodium lauryl sulfate, glycerin, fatty acid glycerin ester, purified lanolin, glycerogelatin, polysorbate, macrogol, vegetable oil, wax, liquid paraffin, white petrolatum, fluorocarbon, nonionic surfactant, propylene glycol, and water.
In order to produce a solid preparation for use in oral administration, an active ingredient is mixed with excipient components, such as, for example, lactose, starch, crystalline cellulose, calcium lactate, or anhydrous silicic acid, to form a powder agent. Otherwise, as necessary, a binder such as white sugar, hydroxypropyl cellulose or polyvinyl pyrrolidone, a disintegrator such as carboxymethyl cellulose or calcium carboxymethyl cellulose, and the like are further added thereto, and the obtained mixture is then subjected to wet or dry granulation to form a granule. In order to produce a tablet, such a powder agent or a granule is directly used, or a lubricant such as magnesium stearate or talc is added thereto, and they are then subjected to tableting. Such a granules or a tablet can be coated with an enteric coating base material such as hydroxypropylmethyl cellulose phthalate or a methacrylic acid-methyl methacrylate polymer to form an enteric coated preparation. Otherwise, such a granule or tablet can be coated with ethyl cellulose, carnauba wax, or hydrogenated oil to form a prolonged action preparation. Moreover, in order to produce a capsule, a powder agent or a granule is filled into a hard capsule. Otherwise, an active ingredient is directly used, or is dissolved in glycerin, polyethylene glycol, sesame oil, olive oil, etc., and the obtained mixture is then coated with a gelatin film, so that a soft capsule can be prepared.
In order to produce an injection, an active ingredient is dissolved in distilled water for injection, together with, as necessary, a pH adjuster such as hydrochloric acid, sodium hydroxide, lactose, lactic acid, sodium, sodium monohydrogen phosphate or sodium dihydrogen phosphate, and a tonicity agent such as sodium chloride or glucose, and thereafter, the obtained solution is subjected to aseptic filtration, and is then filled into an ampoule. Otherwise, mannitol, dextrin, cyclodextrin, gelatin, etc. are further added to the obtained solution, and the thus mixed solution is then subjected to vacuum-freeze drying, so that the injection may be prepared as an injection that is dissolved at the time of use. Alternatively, lecithin, polysorbate 80, polyoxyethylene hydrogenated castor oil, etc. can be added to the active ingredient, and they can be then emulsified in water to prepare an emulsion for injection.
In order to produce an agent for rectal administration, an active ingredient may be humidified and dissolved, together with a suppository base material such as cacao butter, fatty acid tri-, di- and mono-glyceride, or polyethylene glycol, and thereafter, the obtained mixture may be poured into a mold and may be then cooled. Otherwise, an active ingredient may be dissolved in polyethylene glycol, soybean oil or the like, and the obtained mixture may be then coated with a gelatin film.
The applied dose and the number of doses of the therapeutic drug or the like according to the embodiment of the present invention are not particularly limited, and the applied dose and the number of doses can be selected, as appropriate, by a doctor's judgement, depending on conditions such as the purpose of prevention and/or treatment of deterioration/progression of a therapeutic target disease, the type of the disease, and the body weight, age, etc. of a patient.
In general, the daily dose of the present therapeutic drug or the like for an adult by oral administration is approximately 0.01 to 1000 mg (the weight of the active ingredient), and the present therapeutic drug or the like can be administered once per day, or divided over several administrations per day. When the present therapeutic drug or the like is used in the form of an injection, it is desired to continuously or intermittently administer the therapeutic agent or the like to an adult at a daily dose of 0.001 to 100 mg (the weight of the active ingredient).
The therapeutic drug or the like according to the embodiment of the present invention may also be prepared in the form of a sustained release preparation, such as an implant and a delivery system encapsulated into a microcapsule, by using a carrier capable of preventing the immediate removal of the drug from the body. Examples of such a carrier that can be used herein may include biodegradable and biocompatible polymers such as ethylene vinyl acetate, polyacid anhydride, polyglycolic acid, collagen, polyorthoester, and polylactic acid. Such materials can be easily prepared by a person skilled in the art. In addition, a liposome suspension can also be used as a pharmaceutically acceptable carrier. Such a liposome is not limited, but can be prepared as a lipid composition comprising phosphatidylcholine, cholesterol and PEG-induced phosphatidyl ethanol (PEG-PE), by being passed through a filter having a suitable pore size, so that it can have a size suitable for the use thereof, and thereafter, the lipid composition can be purified by a reversed phase evaporation method.
The therapeutic drug or the like according to the embodiment of the present invention may be provided in the form of a kit together with an instruction manual regarding an administration method and the like. The drug included in the kit is supplied with a container produced with a material that effectively sustains the activity of structural components of the therapeutic drug or the like for a long period of time, is not adsorbed on the inner side of the container, and does not degenerate the structural components. For instance, a sealed glass ampoule may include a buffer or the like, which is enclosed in the presence of neutral and non-reactive gas such as nitrogen gas.
Moreover, the kit may be included with an instruction manual. The instruction manual of the kit may be printed out on a paper or the like, or may be stored in an electromagnetically readable medium such as CD-ROM or DVD-ROM and may be then supplied to users.
A third embodiment of the present invention relates to a method for preventing or treating cancer, comprising administering the therapeutic drug or the like according to the embodiment of the present invention (i.e. the second embodiment of the present invention) to a patient.
The term “to treat” means herein to stop or alleviate progression and deterioration of the pathological condition induced in a mammal affected with cancer. On the other hand, the term “to prevent” means herein to previously stop the onset of cancer in a mammalian patient which is likely to be affected with cancer. The “mammal” as a preventive or therapeutic target means any given animal classified into Mammals. Examples of the mammal may include, but are not particularly limited to, humans, companion animals such as dogs, cats, rabbits and ferrets, and living stock animals such as bovines, pigs, sheep and horses. A particularly preferred “mammal” is a human.
Examples of the cancer (malignant tumor/malignant neoplasm) as a preventive or therapeutic target of the preventive or therapeutic method of the present invention may include hepatocellular carcinoma, bile duct cell carcinoma, renal cell carcinoma, squamous cell carcinoma, basal cell carcinoma, transitional cell carcinoma, adenocarcinoma, malignant gastrinoma, malignant melanoma, fibrosarcoma, myxosarcoma, liposarcoma, leiomyosarcoma, rhabdomyosarcoma, malignant teratoma, angiosarcoma, Kaposi's sarcoma, osteosarcoma, chondrosarcoma, lymphangiosarcoma, malignant meningioma, non-Hodgkin lymphoma, Hodgkin lymphoma, leukemia, brain tumor, epithelial cell-derived neoplasm (epithelial carcinoma), basal cell carcinomas, adenocarcinomas, lip cancer, oral cancer, esophageal cancer, gastrointestinal cancer such as small bowel cancer and stomach cancer, colon cancer, rectal cancer, hepatic cancer, bladder cancer, pancreatic cancer, ovarian cancer, cervical cancer, lung cancer, breast cancer, skin cancers such as squamous cell carcinoma and basal cell carcinoma, prostate cancer, and renal cell carcinoma. In addition, examples of the cancer may also include known other cancers that affect the epithelium, mesenchyme, and blood cells in the whole body.
A fourth embodiment of the present invention relates to a method for diagnosing or auxiliarily diagnosing cancer, comprising measuring the amount of TCTP mRNA or TCTP protein that is present in a sample derived from a subject.
In a subject in whom cancer is developed, the amount of TCTP protein or TCTP mRNA in tumor tissues or in blood is significantly increased, in comparison to that in s healthy subject (a person in whom the onset of cancer is not confirmed) (see, for example,
In the present embodiment, the sample derived from a subject is not limited, but for example, blood (including components derived from blood, such as serum), tissues suspected to be a malignant tumor, or the like can be used. As a method of measuring the amount of TCTP protein in a sample, a person skilled in the art can easily select an appropriate method, and for example, an immunoassay, such as an ELISA (enzyme-linked immuno-sorbent assay) method or a Western blotting method, can be applied. In addition, as a method of measuring the amount of TCTP mRMA in a sample, a person skilled in the art can easily select an appropriate method, and for example, a real-time PCR (RT-qPCR) method can be applied.
When the present description is translated in English and the translation document includes singular terms with the articles “a,” “an,” and “the,”, these terms include not only single items but also multiple items, unless otherwise clearly specified.
Hereinafter, the present invention will be further described in the following examples. However, these examples are only illustrative examples of the embodiments of the present invention, and thus, are not intended to limit the scope of the present invention.
C57BL/6 and BALB/c mice were purchased from CLEA Japan Inc. ApcΔ716 mice were produced according to the previous report (19), and were used in the background of C57BL/6 mice. TCTP flox mice were kindly provided by Dr. Hsin-Fang Yang-Yen of Academia Sinica (Republic of China) and were used in the background of C57BL/6 mice. Villin-CreERT2 mice were kindly provided by Dr. Sylvie Robine of Institut Curie (France) and were used in the background of C57BL/6 mice. MyD88 and IPS-I-deficient mice were kindly provided by Dr. Shizuo Akira of Osaka University, and were used in the background of C57BL/6 mice. TLR2 and TLR4-deficient mice were purchased from Oriental Bio Service, Inc., and were used in the background of C57BL/6 mice. STING-deficient mice were kindly provided by Dr. Glen N. Barber of University of Miami (U.S.A.), and were used in the background of C57BL/6 mice. RAG1 knockout mice were kindly provided by Dr. Shinsuke Taki of Shinshu University. Both male and female mice (6-12 weeks old) have been used in the present Examples, unless otherwise specified. All animal experiments were approved by the University of Tokyo's Animal Research Committee.
RAW264.7 cells, the mouse melanoma cell line B16F10 cells, the mouse fibrosarcoma cell line Meth-A cells, and HEK293T cells were obtained from RIKEN BioResource Center (Japan). The mouse colon carcinoma cell line SL4 was kindly provided by Dr. T. Irimura (Juntendo University). RAW264.7 cells, B16F10 cells, and HEK293T cells were maintained in DMEM (Nacalai Tesque, Inc.) supplemented with 10% FBS (HyClone). Meth-A cells were maintained in RPMI (Nacalai Tesque, Inc.) supplemented with 10% FBS. SL4 cells were maintained in DMEM-F12 (Gibco) supplemented with 10% FBS. For preparation of peritoneal exudate cells (PECs), mice were intraperitoneally injected with 2 ml of 4% thioglycollate (DIFCO solution), and 4 days later, the abdominal cavity was washed with PBS to collect PECs. The cells were incubated in RPMI supplemented with 10% FBS on a petri dish overnight. After completion of the incubation, the cells were washed with an RPMI medium, and were then used in the subsequent experiments.
Tumor-infiltrating cells were recovered after subcutaneous transplantation of a tumor into mice, and were then analyzed by flow cytometry. The excised tumor was finely minced, and was then treated with collagenase (0.75 mg/ml, cat# 11088882001, Roche), DNase I (40 μg/ml, cat# 11284932001, Roche), and dispase (0.5 mg/ml, cat# 17105041, Thermo Fisher Scientific), and thereafter, the resultant was intensively stirred (180 rpm, 37° C., 1 hour). The obtained cell suspension was passed through a cell strainer (cat# 352340, Falcon) and was then treated with an RBC lysis buffer (cat# 00-4333-57, Invitrogen). After washing with PBS, the cells were first incubated with an anti-CD16/32 antibody (clone 93, cat# 101302, BioLegend) on ice for 5 minutes. Thereafter, the cells were stained in PFE (PBS supplemented with 2% FBS and 1 mM EDTA) on ice for 20 minutes. The resulting cells were analyzed by LSR Fortessa (BD Biosciences). Cell sorting of the tumor-infiltrating cells was performed using FACSAria II (BD Biosciences). The obtained data were analyzed with FlowJo software (BD BioSciences).
The following antibodies were used in flow cytometry analysis or fluorescence-activated cell sorting: Ly6C-AF488 (clone HK1.4, cat# 128022, BioLegend), NK1.1-FITC (clone PK136, cat# 553164, PharMingen), CD11b-PE (clone M1/70, cat# 101208, BioLegend), CD3c-PE (clone 145-2C11, cat#12-0031-81, eBioscience), CD11c-APC (clone N418, cat# 17-0114-81, eBioscience), B220-APC (clone RA3-6B2, cat# 20-0452-U025, TONBO biosciences), F4/80-PerCP/Cy5.5 (clone BM8, cat# 123128, BioLegend), CD8a-PerCP/Cy5.5 (clone 53-6.7, cat# 100734, BioLegend), Ly6G-PE/Cy7 (clone 1A8, 127618, BioLegend), CD4-PE/Cy7 (clone GK1.5, cat# 100422, BioLegend), CD45.2-Pacific Blue (clone 104, cat# 109820, BioLegend), anti-CD16/32 (clone 93, cat# 101302, BioLegend), PD-1-APC (clone 29F.1Al2, cat# 135209, BioLegend), and PD-L1-APC (clone 10F.9G2, cat# 124311, BioLegend).
A culture supernatant was prepared according to the previous report (Non Patent Literature 5). Specifically, SL4 cells were incubated with indomethacin (10 μM) overnight for elimination of PGE2 (prostaglandin E2), and were then suspended in PBS at a concentration of 108 cells/ml. Thereafter, the cells were subjected to freeze-and-thaw cycles 5 times, using a 37° C. constant-temperature bath and liquid nitrogen. After that, the cells were centrifuged at 8,000×g for 5 minutes, and necrotic cell debris were removed. A culture supernatant was obtained by filtration through a 0.45 μm membrane filter (Millipore).
LPS (055:B5) was purchased from SIGMA-Aldrich (cat# L2637). Oligonucleotides were purchased from FASMAC. Indomethacin was purchased from WAKO (cat# 093-02473). Recombinant IL-l1α was purchased from Peprotech (cat# 211-11A). Recombinant TCTP was purchased from ORIGENE (cat# TP301664). TUNEL staining was carried out using in situ Apoptosis Detection Kit (cat# MK500, TaKaRa). The endotoxin level of the recombinant TCTP was assessed using LAL Endotoxin Assay Kit, Chromogenic, ToxinSensor (cat# L00350, Genscript), and the endotoxin level was confirmed to be <0.1 EU/μg.
A culture supernatant from necrotic cells was first treated with a DNasel solution (0.5 U/μl; TaKaRa Bio), RNaseA (0.25 mg/ml; MACHEREY-NAGEL), or PBS, and was then incubated at 37° C. for 30 minutes. Regarding a proteinase K treatment, the culture supernatant was treated with proteinase K (100 μg/m1; TaKaRa Bio) at 37° C. for 1 hour. Thereafter, the protease K-treated sample was treated with APMSF (5 mM; Nacalai Tesque, Inc.) on ice for 20 minutes so as to inactivate the proteinase K. Since the induction of the cytokine mRNA was abolished only by the proteinase K treatment, it was suggested that the activator be a protein. Subsequently, the culture supernatant was subjected to ion exchange chromatography (Hitrap Capto S column (cat# 17544105, GE healthcare) or Hitrap Capto Q column (cat# 11001302, GE healthcare)). The Hitrap Capto S column or the Hitrap Capto Q column was first washed with 1 ml of DDW, and was then equilibrated with 30 ml of PBS. Thereafter, the column was charged with 5 ml of a culture supernatant of SL4 cells, and was then washed with 5 ml of PBS. Flow-through was recovered, and PECs were then added thereto. As a result of an RT-qPCR analysis, it was found that the flow-through of the Hitrap Capto S column induces the cytokine mRNA, but that the flow-through of the Hitrap Capto Q column does not induce it. These results suggest that the molecule(s) as identification targets bind to the Hitrap Capto Q column.
Based on the above-described results, the following purification procedures, in which ion exchange chromatography was combined with size exclusion chromatography, were carried out. First, the Hitrap Capto S column was washed with 1 ml of DDW, and was then equilibrated with 30 ml of PBS. The column was charged with 5 ml of a culture supernatant of SL4 cells, and was then washed with 5 ml of PBS. Flow-through was recovered, and was then loaded on a Hitrap Capto Q column that had been equilibrated as in the case of the Hitrap Capto S column. Subsequently, the column was washed with 20 ml of PBS, and was then eluted with 5 ml of 0.4 M NaCl. The eluent was concentrated by Spin-X UF 10k MWCO (cat# CLS431488, MERCK). Finally, size exclusion chromatography was performed using a Superdex 200 Increase 10/300 GL column connected with AKTA purifier (GE Healthcare). The column was equilibrated with 2-fold column volumes of PBS, and the above concentrated eluent was loaded onto the column. Eluted droplets (18 droplets) were continuously recovered into wells of a 48-well plate, using AC-5700P MicroCollector (ATTO). Each fraction was added to PECs or RAW264.7 cells, and Cxcl1, Cxcl2,Tnf and Il1b mRNA levels were determined by RT-qPCR. The 18th to 27th fractions were subjected to silver staining with SilverQuest (cat# LC6070, Invitrogen), and the densest band that was correlated with cytokine inducing activity was subjected to LC-MS (liquid chromatography-mass spectrometry).
Total RNA was extracted from tissues or cells, using NucleoSpin RNA II (MACHEREY NAGEL), and was then reverse-transcribed using PrimeScript RT Master Mix (TaKaRa Bio). An RT-qPCR reaction was performed on LightCycler 480 (Roche Life Science) or LightCycler 96 (Roche Life Science), using the TB Green® Premix Ex Taq™ II (TaKaRa Bio). The obtained values were normalized with respect to the expression level of Gapdh mRNA. Primers having the following sequences were used.
TCTP KO SL4 cells, TCTP KO B16F10 cells, and TCTP KO Meth-A cells were produced by CRISPR/Cas9 genome editing using the CRISPR design tool (http://www.genome-engineering.org, accessed May 2017). The genomic sequences of the TCTP gene (5′- CGGGCGGAAAAGGCCGACGC-3′ (SEQ ID NO: 38) and 5′-AGGCCCGCCATTTCCCGCGC-3′ (SEQ ID NO: 39)) were targeted. The first exon of the TCTP gene was flanked by the above two sequences, SEQ ID NO: 38 and SEQ ID NO: 39. Oligonucleotides corresponding to these guide sequences were cloned into the Bbsl sites of pSpCas9(BB)-2A-GFP (PX458) (Addgene) and pSpCas9(BB)-2A-Puro (PX459) V2.0 (Addgene), respectively. The expression vector constructs were both introduced into SL4 cells. The construct-introduced cells were first selected with puromycin, and were then subjected to single cell sorting using FACSAria II (BD Biosciences) or SH800S (SONY).
Immunoblot analysis was performed according to the previous report (Inoue et al., Nature 434, 243-249, doi: 10.1038/nature03308 (2005)). β-Actin (cat# A5441) was purchased from Sigma-Aldrich. TCTP antibodies (cat# ab133568 and cat# ab37506) were purchased from Abcam. TCTP antibody (cat# 5128S) was purchased from Cell Signaling Technology. β-Actin was used as a loading control. In order to determine the amount of TCTP in serum, the serum was subjected to immunoblot analysis using a TCTP antibody (ab133568). Recombinant TCTP (cat# TP301664, OriGene) was used in the measurement of the TCTP amount. Anti-rabbit IgG-HRP (cat# NA934V, GE Healthcare) or anti-mouse IgG-HRP (cat# NA931V, GE Healthcare) was used as a secondary antibody. Immunoblotting signals were detected by FUSION Solo S (Vilber-Lourmat), and were then analyzed by FUSION Capt Advanced software (Vilber-Lourmat).
1-10. In vitro cell proliferation analysis
WT SL4 cells and TCTP KO SL4 cells (2.5×105 cells), B16F10 cells (1.2×105 cells), or Meth-A cells (2.5×105 cells) were seeded in each well of a 6-well plate. Every 3 days, one eighth of the cells were passaged to a new 6-well plate. The number of the cells was calculated on Days 3, 6, and 9.
1-11. Proliferation assay of subcutaneously transplanted tumor
2×105 SL4 cells, 1×105 B16F10 cells, or 5×105 Meth-A cells were transplanted into the subcutis of mice. The tumor volume was calculated according to the equation: average volume=πab2/6 (wherein a and b indicate the major axis and the minor axis, respectively).
1-12. Apc+/Δ716 colorectal cancer models
TCTPflox/flox, Apc+/Δ716 mice or TCTPflox/flox, Apc+/Δ716, Villin-CreERT2 mice were treated with tamoxifen at a dose of 4 mg/mouse once a week, starting from 5 weeks of age. Intestinal tumors of these mice were analyzed using stereoscope (Leica S9 D, Leica), when the mice were 10-week-old.
DNA encoding the human IL-2 peptide (MYRMQLLSCIALSLALVTNS: SEQ ID NO: 40) was fused with the 5′-terminus of mouse TCTP cDNA. IL-2ss-TCTP and WT TCTP cDNA fragments were each inserted into a pMXs-IRES-GFP retroviral expression vector. Introduction of the vector into TCTP KO SL4 cells by retrovirus was carried out according to the previous report (Chiba et al., Elife. 2014 Aug. 22; 3:e04177. doi: 10.7554/eLife.04177.). Thereafter, GFP-positive cells were sorted using Cell Sorter SH800S (SONY). Mock cells or IL-2ss-TCTP-introduced cells were identified by performing the aforementioned immunoblotting analysis on a culture supernatant recovered from a 60-mm culture dish, on which 2×106 cells had been seeded.
A tumor was excised on Day 21 after the transplantation, and was then finely minced in a lysis buffer (20 mM Tris-HCl, 150 mM NaC1, 1 mM EDTA, 1% Triton X-100, 1 mM Na3VO4, and 1 mM APMSF). Thereafter, the resultant tumor was incubated on ice for 30 minutes, a lysate was then centrifuged, and a supernatant was then recovered for use in ELISA. The amounts of mouse CXCL1 and CXCL2 generated in TIME were quantified using an ELISA kits (R&D Systems) according to an instruction manual included therewith.
T cells were collected from the splenocytes of non-tumor bearing mice, using Pan T cell isolation kit II (Miltenyi Biotec). The prepared cells were stained with CFSE, using CellTrace™ CFSE Cell Proliferation Kit (Thermo Fischer Scientific) according to an instruction manual included therewith. PMN-MDSCs were collected from the splenocytes of mice on Days 17-19 after subcutaneous transplantation of SL cells (2×105 cells), using Ani-Ly6-G MicroBeads (Miltenyi Biotec). Neutrophils were collected from non-tumor bearing C57BL/6 mice by the same method as that for PMN-MDSCs. CFSE-labelled T cells (1×105 cells) and PMN-MDSCs (5 x104 cells, 2.5×104 cells, or 1.25×104 cells) were seeded in a 96-well plate. Proliferation of T cells was induced for 3 days, using Dynabeads Mouse T-Activator CD3/CD28 (Thermo Fischer Scientific), and thereafter, a flow cytometry analysis was carried out to evaluate a CFSE dilution rate in the T cells.
1-16. In vivo Depletion of CD8+ T Cells, NK cells and PMN-MDSCs
For depletion of NK cells, anti-asialo GM1 (cat# 014-09801, WAKO) or rat control IgG (cat# 31933, Thermo Fisher) was intraperitoneally transplanted into the mice (200 μg/mouse) on Days 1, 3, 7, 11, and 15 after the transplantation of the tumor cells. For depletion of CD8+ T cells, anti-CD8α (clone 2.43, cat# BE0061, Bio X Cell) or rat control IgG (cat# 31933, Thermo Fisher) was intraperitoneally transplanted into the mice (100 μg/mouse) on Days 1, 3, 7, and 11 after the transplantation of the tumor cells. For depletion of NK cells and CD8+T cells, anti-asialo GM1 (cat# 014-09801, WAKO) or rat control IgG (cat# 31933, Thermo Fisher) was intraperitoneally transplanted into RAG1 KO mice (200 μg/mouse). For depletion of PMN-MDSCs, an anti-Ly6G antibody (cat# BE0075-1, Bio X Cell) or rat control IgG was intraperitoneally transplanted into the mice on Days 1, 3, 5, 7, 9, and 11 after the transplantation of the tumor cells.
1-17. Dihydroartemisinin (DHA) or o-Vanillin Treatment
DHA (Selleck, TX, USA) was dissolved in DMSO, and was then administered intraperitoneally (50 mg/kg) into the mice every day, starting from Day 1 of the tumor transplantation. Regarding combined administration of an anti-PD-1 antibody and DHA, the DNA administration was terminated on Day 6. 0-vanillin (cat# 120804-10G, Merck) was first dissolved in DMSO to a concentration of 500 mg/ml, and was then diluted with PBS to a final concentration of 50 mg/ml. The diluted solution was orally administered (50 mg/kg) to the mice every other day, starting from Day 1 of the tumor transplantation.
Mouse monoclonal antibodies reacting against TCTP were prepared according to a standard hybridoma technology by MAB Institute, Inc. (http://www.monoclo.com; Nagano, Japan). BALB/c mice were immunized with a synthetic peptide (EDGVTPYMIFFKDGLEMEKC; SEQ ID NO: 25) that is a partial sequence of human TCTP. Antibodies were screened based on an immunoblotting analysis and an immunoprecipitation analysis against TCTP. As a result, antibodies 55F3, 44E1 and 51A9 were obtained. Regarding the treatment using an antibody, 55F3 or control IgG (cat# 0107-01, SouthernBiotech) was intraperitoneally transplanted into the mice at a dose of 200 μg per mouse.
The amino acid sequences of the heavy chain and light chain of the prepared monoclonal antibodies were determined with reference to PLoS ONE e0218717,14: 2019.
Total RNA was extracted from hybridoma cells, and cDNA was then synthesized using RT (reverse transcription) primers specific to the variable regions of the antibody heavy chain and light chain (mIGK RT, mIGHG RT, and Template-switch oligo F). Subsequently, the prepared cDNA was used as a template, and a PCR reaction was then carried out using specific primers (ISPCR, mIGK PCR, and mIGHG PCR). The obtained cDNA was subjected to TA cloning (pTA2 vector, TOYOBO) for sequencing.
Detailed experimental conditions are as follows.
(1) Preparation of cDNA
Primers used in reverse transcription reaction
Reaction solution (I) (cDNA synthetic reaction)
2 μL of 50 ng/μL total RNA,
1 μL of 10 μM primer for reverse transcription reaction (mIGK RT, mIGL RT, or mIGHG), and
1 μL of 10 mM dNTPs.
These substances were mixed with one another in a 8-well strip tube.
Reaction solution (II) (cDNA synthetic reaction)
2.2 μL of H2O,
2 μL of 5× SMARTScribe buffer,
1 μL of 20 mM DTT,
0.3 μL of 100 μM template-switch oligo F, and
0.5 μL of 100 U/μL SMARTScribe Reverse Transcriptase.
These substances were mixed with one another in a 8-well strip tube. The reaction solution (I) was subjected to a heat treatment using a thermal cycler at 72° C. for 3 minutes. After completion of the heat treatment, 6 μL of the reaction solution (II) was added to the reaction solution (I), and the thus mixed solution was then incubated using a thermal cycler at 42° C. for 60 minutes. Thereafter, the reaction mixture was subjected to a heat treatment at 70° C. for 5 minutes, and the reaction was then terminated.
The synthesized cDNA was used as a template, and a PCR reaction was carried out using the following primers. Using the obtained amplified product, the DNA sequences of the variable regions of the antibody heavy chain and light chain, and thereafter, amino acid sequences encoded thereby were determined. Primers
25 μL of 2× PCR buffer for KOD FX
10 μL of 2 mM dNTPs
3 μL of Synthesized cDNA from the RT reaction
2.5 μL of 10 μM universal forward primer ISPCR
2.5 μL of 10 μM reverse PCR primer (mIGK PCR, mIGL PCR, or mIGHG PCR)
6 μL of H2O
1 μL of KOD FX (1 U/μL)
After a reaction performed at 98° C. and 30 seconds,
98° C., 15 seconds,
63° C. to 57.5° C., 30 seconds (the temperature was decreased by 0.5° C. in each cycle), and
72° C., 30 seconds.
The aforementioned reaction was carried out for 10 cycles, and further, a reaction consisting of:
Thereafter, a reaction was carried out at 72° C. for 7 minutes, and the reaction mixture was then left at rest at 4° C.
The determined amino acid sequences of the variable regions of the antibody heavy chain and light chain were matched with the antibody sequence database (http://www.abybank.org/kabat/ and http://www.bioinf.org.uk/abs/info.html#cdrid, etc.), and amino acid sequences corresponding to CDRs according to Kabat definition were specified.
1-19. Analysis of Data Obtained from Patients with Colorectal Cancer
The TCGA dataset of 640 colorectal cancer patients was downloaded from the cBioPortal (https://www.cbioportal.org/, accessed December 2019). Then, GISTIC 2.0 analysis was carried out in the cBioportal platform.
SL4 tumor and ApcΔ716 mouse tumor-derived large intestine were preserved in PBS containing 4% paraformaldehyde, and were then embedded in paraffin. Hematoxylin and eosin (H&E) staining, TUNEL staining, and 3,3′-diaminobenzidine (DAB) staining were carried out on CD31 (cat# ab28364, Abcam) or Ly6G (cat# 127601, Biolegend) at the core laboratory for pathological analysis of the Institute of Medical Science, the University of Tokyo. Formalin fixed paraffin embedded tissues of the large intestines of colorectal cancer patients and normal large intestine epithelial samples of the same patients were prepared and analyzed at Kanazawa University. This analysis was approved by Human Genome/Gene Analysis Research Ethics Committee of Kanazawa University (2016-086-433), and written consent was obtained from the patients.
TCTP (cat# 133568, Abcam) or CD15 (cat# M363129, Dako) was used in DAB staining. Briefly, a paraffin-embedded sample was deparaffinized by incubation with xylene two times, and was then dehydrated with a series of ethanol, followed by rehydration in PBS. Heat-induced epitope retrieval was performed using an antigen retrieval reagent pH9 (cat# 415211, NICHIREI BIOSCIENCES INC.) at 121° C. for 10 minutes. In order to deactivate endogenous peroxidase, REAL Peroxidase-Blocking solution (cat# S2023, DAKO) was used according to an instruction manual included therewith, followed by blocking with 1% BSA/TBST at room temperature for 30 minutes. Sections were incubated together with a TCTP antibody or a CD15 antibody at room temperature for 1 hour. Detection of the primary antibody was performed using Histofine simple stain MAX-PO (MULTI) (cat# 424151, NICHIREI BIOSCIENCES INC.), and using DAB (cat# 415171, NICHIREI BIOSCIENCES INC.) as a substrate. Samples were counterstained with hematoxylin (cat no. 415081, NICHIREI BIOSCIENCES INC.). Quantification of signal intensity from TCTP was performed according to the previous report, using ImageJ Fiji (Bio Protoc. 2019 Dec 20; 9(24): e3465.). The average intensity in normal colonic mucosa was set as 1. Quantification of CD31-positive areas was performed using a BZ-9000 microscope and a cell count software BZ-H4C (Keyence).
PECs were stimulated with a culture supernatant of necrotic cells (2×106 SL4 cells). After incubation for 2 hours, total RNA was extracted and was then subjected to an analysis with Clariom S Array (Thermo Fisher Scientific). Volcano plot was produced by Transcriptome Analysis Console (TAC) software v4.0 (Thermo Fisher Scientific). Microarray data were registered in the Gene Expression Omnibus (GEO) database (Accession No. GSE150465).
Cells were cultured on a 35 mm glass-bottom dish (MATSUNAMI) overnight, and thereafter, the cultured cells were washed with PBS and were then fixed with 4% paraformaldehyde/PBS for 15 minutes. After washing with PBS, the resulting cells were permeabilized with 0.5% Triton X-100/PBS for 15 minutes, and were then blocked with 3% BSA/PBS. Subsequently, the cells were incubated together with the anti-TCTP antibody (ab37506) for 2 hours, followed by washing, and the resulting cells were treated with a secondary antibody (Alexa Fluor 594 Goat anti-rabbit IgG, cat# A-11012, Invitrogen) for immunostaining. After washing with PBS, nuclear counter-staining was carried out using VECTASHIELD Hard Set Mounting Medium with DAPI (cat# H-1500, VECTOR LABORATORIES, INC), and immediately thereafter, an analysis was carried out by a C2si confocal microscopy system (NIKON) equipped with ECLIPSE Ti microscopy (NIKON).
Bone marrow cells and splenocytes were collected from (tumor-bearing) mice on Day 17 after subcutaneous transplantation of SL4 cells (2×105 cells). Ly-6G+ cells were separated using anti-Ly6-G MicroBead Kit, mouse (Miltenyi Biotec). The separated Ly-6G+ cells (4×106 cells) were intravenously injected into mice on Days 1, 4, 7, 10, and 13 after subcutaneous transplantation of TCTP KO SL4 cells (2×105 cells).
HEK293T cells (5×106 cells) were seeded, and were transiently transfected with only pCXNII-FLAG-hTCTP (2 μg), or with pCXNII-FLAG-hTCTP (2 μg) in combination with pcDNA3.1-hTLR2-YFP (2 μg), using X-tremeGENE9 (Roche Life Science). A pcDNA3.1-hTLR2-YFP vector was kindly provided by Dr. Douglas Golenbock.
Thereafter, a cell lysate was prepared using a lysis buffer (20 mM Tris-HCL (pH 7.5), 150 mM NaCl, 1 mM EDTA, 1% Triton X-100, and 1 mM PMSF). The cell lysate (1 mg) was subjected to immunoprecipitation using 1 μg of an anti-GFP antibody (598; MBL) and 30 μl of Dynabeads Protein G for immunoprecipitation (Thermo Fisher Scientific). Thereafter, the obtained immunoprecipitate was subjected to immunoblotting using an anti-GFP antibody or an anti-FLAG M2 antibody (Sigma Aldrich).
Mouse TLR3, TLR7, TLR9, and human CD14 cDNAs were cloned into a pCXNII-HA vector. A Human TLR2 cDNA construct (pcDNA3.1-hTLR2-YFP), a mouse TLR3 cDNA construct (pCXNII-HA-mTLR3), a mouse TLR7 cDNA construct (pCXNII-HA-mTLR7), or a mouse TLR9 cDNA construct (pCXNII-HA-mTLR9), together with an NFκB luciferase reporter (pNFκB-Luc (Stratagene)), was transfected into HEK293T cells. As for TLR2 stimulation, a human CD4 cDNA construct (pCXNII-HA-hCD14) was co-transfected into the cells. Twenty-four hours after the transfection, 2×104 cells were seeded in a 96-well dish. Twenty-four hours after the seeding, the cells were treated with recombinant TCTP or each TLR agonist. Thereafter, luciferase activity was measured with Pikka Gene Dual Assay kit (cat# PD-11, TOYO B-Net), using MicroLumat Plus LB96V (Berthold Technologies) according to an instruction manual included therewith.
Quantification of G-CSF (cat# 560152, BD Biosciences) and GM-CSF (cat# 558347, BD Biosciences) was performed using cytometric bead assay (CBA) according to an instruction manual included therewith.
In order to induce apoptosis, serum starvation and adriamycin treatment were carried out. For the serum starvation, SL4 cells (5×104 cells) were seeded in a 48-well dish, and twelve hours after the seeding, the medium was replaced with a serum- free medium. Seventy-two hours after the serum starvation, a culture supernatant was recovered. For the adriamycin treatment, SL4 cells were seeded in the same manner as that for the serum starvation. Twelve hours after the seeding, the cells were treated with a medium containing adriamycin (50 μM) for 24 hours, and thereafter, a culture supernatant was recovered.
In order to induce necrosis, SL4 cells (1×107 cells) were suspended in 1 ml of PBS. Freezing and thawing were performed as described in the above “1-4. Preparation of culture supernatant.” As a control, a supernatant of SL4 cells incubated in PBS for the same period of time as that for the freezing and thawing was used. Hypoxic treatment (1% O2, 5% CO2) was performed using a multi-gas incubator (MCO-SMUV-PJ, Panasonic).
Human sera of colorectal cancer patients and non-cancer patients were obtained from Biobank Japan. The present study was approved by the institutional ethics committee of the University of Tokyo (20-239). Quantification of TCTP was carried out by immunoblotting.
TCTP WT cells or TCTP KO cells on a 10 cm dish were lethally irradiated with X-ray (100 Gy). TCTP WT SL4 cells (2×105 cells) were mixed with equal amounts of the above lethally irradiated TCTP WT cells or TCTP KO cells, and the thus obtained mixture was subcutaneously transplanted into C57BL/6 cells.
Sample size and statistical tests were carried out as described in Description of the Drawings. Data were expressed as a mean value ±standard deviation (s.e.m.), unless otherwise specified. One-way ANOVA with Dunnett's or Tukey's multiple comparisons test, Spearman correlation coefficients calculation, Log-rank test and two-sided Student's t-test were performed using Prism 8.0 (GraphPad Software). All alpha levels were 0.05, with P<0.05 considered a significant difference.
Since a considerable number of tumor cells die during tumor proliferation (mostly, due to necrosis), we made a working hypothesis that the environment of the necrotic cells may function as an immunomodulator for MDSCs (myeloid-derived suppressor cells; i.e. bone marrow-derived immunosuppressor cells) in the tumor immune microenvironment (TIME). As an approach to identify a dead tumor cell-derived immunomodulator, a culture supernatant model of necrotic SL4 cells (a mouse colorectal cancer cell line) was first used (Non Patent Literature 5) (
In order to identify chemokines derived from dead tumor cells, which induce the expression of Cxcl1 and Cxcl2, molecules of interest were attempted to be isolated from a culture supernatant of SL4 cells, by applying ion exchange chromatography and size exclusion chromatography. The culture supernatant of SL4 cells was passed through an anion-exchange column (Hitrap Q) and a cation-exchange column (Hitrap S). Flow-through was recovered from the Hitrap S column, and was then loaded on the Hitrap Q column. A fraction binding to Hitrap Q was recovered, and was then loaded on the size exclusion column (Superdex 200). The obtained fractions were each added to PECs (Cxcl1, Cxcl2, and Il1b; 2×105 cells) or RAW264.7 cells (Tnf; 2×105 cells), and were then incubated for 2 hours. Cxcl1, Cxcl2, Tnf, and Il1b mRNAs were quantified by an RT-qPCR method. The peak fraction of each mRNA expression level was subjected to SDS-PAGE and sliver staining, and thereafter, liquid chromatography mass spectrometry (LC-MS) was carried out on the most abundant protein. As a result, it was revealed that TCTP (Tumor cell-derived translationally controlled tumor protein) would be a candidate inducer of the above-described each mRNA. It has been reported that TCTP is present in the cytoplasm of eukaryotic cells (Non Patent Literature 7, Non Patent Literature 8, and Non Patent Literature 9). However, the function of TCTP that is present outside of the cells has not been known so far.
PECs were stimulated with recombinant TCTP, and the expressed mRNA was then quantified by RT-qPCR. As a result, it was observed that the mRNA expression of Cxcl1 and Cxcl2 and other cytokines (Tnf and Il lb) was induced (
TCTP was abundantly present in a culture supernatant of dead tumor cells (tumor dead cells), whereas living tumor cells (tumor living cells) hardly released TCTP (
Taking into consideration the above-described results, the influence of TCTP on proliferation of tumors formed by TCTP-expressing SL4 cells and TCTP-deficient SL4 cells was studied. Whole lysates of TCTP-expressing SL4 cells (TCTP WT SL4: WT) and TCTP-deficient SL4 cells (TCTP KO SL4: KO) were prepared, and immunoblotting was then performed on TCTP and β-actin, so that it was confirmed that TCTP was deleted in TCTP KO SL4 (
The aforementioned results show that TCTP promotes proliferation of a tumor in vivo.
Whether or not dead tumor cell-derived TCTP promotes tumor growth was studied. When TCTP WT SL4 cells (dead WT cells) irradiated with a lethal amount of X-ray were administered to mice, it promoted the growth the TCTP WT SL4 cell-derived tumor. On the other hand, when TCTP KO SL4 cells (dead KO cells) irradiated with a lethal amount of X-ray were administered to mice, it did not promote the growth of a tumor (
Further, in order to reveal the role of TCTP in tumor progression, colorectal tumor models promoted by deletion mutation (ApcΔ716) of an Apc gene as a tumor suppressor were studied in the presence or absence of a TCTP gene (
Next, whether or not TCTP released to the outside of the cells promotes tumor proliferation was studied. For extracellular secretion of TCTP, using a retroviral gene transfer vector, cDNA encoding a chimeric TCTP protein fused with a human IL-2 signal sequence was allowed to express in TCTP KO SL4 cells, and the resulting cells (IL-2ss-TCTP SL4 cells) were then allowed to proliferate in a cell medium. A TCTP protein was detected in vitro in a culture supernatant (
From the above results, it was demonstrated that TCTP released to the outside of the cells functions as an immunomodulator, and functions as a factor of promoting tumor proliferation in vivo.
Considering the above-obtained results, it is conceived that TCTP released from dying tumor cells would induce CXCL1 and CXCL2, which would induce PMN-MDSCs to TIME and would suppress antitumor immune response in the TIME, so that they can promote tumor proliferation.
In fact, when the expression level of CXCL1 in TCTP KO SL4 tumors was compared with the expression level of CXCL1 in TCTP WT SL4 (TCTP-expressing SL4) tumors, the expression level of CXCL1 was significantly high in the TCTP WTSL4 tumors (
Next, tumor-infiltrating immune cells were prepared from TCTP WT SL4 tumors and TCTP KO SL4 tumors, and were then analyzed by flow cytometry. As shown in
In order to confirm that the above CD11b+Ly6ClowLy6G+ cells actually indicate PMN-MDSCs, CD11b+Ly6ClowLy6G+ cells derived from SL4 tumor-bearing mice and CD11b+Ly6ClowLy6G+ cells derived from mice that did not bear SL4 tumors were subjected to in vitro T cell proliferation assay. As shown in
The results of the aforementioned MDSC adoptive immunity suggest that antitumor lymphocytes still activate even in mice bearing TCTP KO tumors. As shown in
In particular, proliferation of TCTP KO SL4 tumors was partially recovered by the removal of either CD8+ T cells or NK cells (
The aforementioned results suggest that PMN-MDSCs that are incorporated into the TIME by TCTP released from tumor cells suppress the antitumor immunosuppressive action of CD8+ T cells and NK cells, and promote tumor proliferation, at least, in some parts.
4. Identification of Cells and Receptors, on which TCTP Act
From the previous results, it is conceived that a TCTP-CXCL1/2-PMN-MDSC pathway is associated with suppression of antitumor immunity in the TIME (tumor immune microenvironment). Hence, next, the cell types that become factors of induction of chemokines in the TIME were studied. Subsets of immune cells were sorted from the TIME of TCTP WT SL4 tumors and the TIME of TCTP KO SL4 tumors, and the expression levels of chemokine mRNAs were then examined. As a result, D11b+Ly6ChighLy6G cells (M-MDSCs) were found to express the highest level of Cxcl l mRNA (
Next, whether or not TCTP-induced chemokine activates specific receptors was studied. First, the involvement of adaptor molecules that act on several innate immune receptors was examined. As shown in
It is notable that SL4 tumors transplanted into Tlr2-deficient mice show proliferation retardation, compared with SL4 tumors transplanted into WT mice (
Next, the influence of a TCTP inhibitory antibody and a TCTP inhibitor on proliferation of tumors was studied. Monoclonal antibodies (55F3, 44E1, and 51A9) reacting against a human TCTP peptide (SEQ ID NO: 25) were prepared. The peptide as set forth in SEQ ID NO: 25 consists of 20 residues on the C-terminal side of a human TCTP protein.
First, it was confirmed that the 55F3 antibody (55F3) has species crossing property to mouse TCTP (
Moreover, the effects of dihydroartemisinin (DHA) that is known to bind to TCTP and to promote decomposition of the TCTP in the proteasome were examined (Non Patent Literature 11). As shown in
The influence of a combination of inhibition of the function of TCTP with inhibition of PD-1 immune checkpoint on tumor proliferation was studied. As a PD-1 immune checkpoint antibody, an antibody of clone RMP1-14 (BioLegend) was used. SL4 cells were transplanted into C57BL/6 mice via subcutaneous injection, and thereafter, 55F3 or DHA was intraperitoneally transplanted into the mice every day, starting from Day 1 after the transplantation. Ten days after the transplantation, an anti-PD-1 monoclonal antibody was administered to the mice, and the tumor volume was then measured. As a result, it was confirmed that the effect of suppressing tumor proliferation is improved by the combined administration of 55F3 or DHA and the PD-1 antagonist antibody, compared with the case of single administration of 55F3 or DHA (
In order to study the role of TCTP in human cancer, the amount of a TCTP protein in the sera derived from human colorectal cancer (CRC) patients was measured. As with mouse models (
Furthermore, the Cancer Genome Atlas (TCGA)-derived data were analyzed. The TCTP mRNA levels, which were classified by the DNA copy numbers of CRC (colorectal cancer) patients (n=376) obtained from TCGA database, are shown in
Based on the aforementioned findings, the function of TCTP in tumor proliferation was summarized in
The present invention provides a therapeutic drug and a therapeutic method for cancer, etc. Therefore, it is greatly expected that the present invention will be utilized in the medical field.
Number | Date | Country | Kind |
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2020-147222 | Sep 2020 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2021/023421 | 6/21/2021 | WO |