Application of SCTAG in esophageal cancer treatment

Abstract

The invention belongs to the field of biological medicine, and particularly relates to application of SCTAG protein as a therapeutic target in treatment or inhibition of esophageal cancer. The application finds that the SCTAG protein can promote proliferation, growth and metastasis of esophageal cancer tumor cells, the SCTAG protein can promote the progress of esophageal cancer through EGFR, and proliferation of esophageal cancer tumor cells and tissues can be inhibited by inhibiting the SCTAG protein and a cell membrane receptor EGFR thereof, so that a brand new thought is provided for esophageal cancer treatment.

Description

Technical Field

[0001] The present application belongs to the field of biomedicine technology, and specifically relates to a method and application thereof for inhibiting or treating esophageal cancer based on SCTAG. Background Art

[0002] Esophageal cancer is a common digestive tract tumor. my country is one of the regions with the highest incidence of esophageal cancer in the world, especially among people over 40 years old, with a higher incidence in men than in women. The exact cause of esophageal cancer is not yet fully understood, but long-term, repeated physical or chemical damage can lead to an increased incidence of esophageal cancer. Currently, smoking and heavy drinking have been shown to be important causes. Other possible causes include poor eating habits, such as eating too few fruits and vegetables, overeating processed meats and fats, eating hard or overheated food, eating too quickly, lack of certain trace elements and vitamins, and genetic susceptibility factors for esophageal cancer.

[0003] The treatment landscape for esophageal cancer is complex and constantly evolving. Current treatment options include surgery, radiotherapy, chemotherapy, and targeted therapy. Surgery is a key treatment option for esophageal cancer. For patients with early-stage esophageal cancer, surgical resection is the preferred treatment. Advances in surgical techniques, such as the use of minimally invasive surgery, have reduced surgical trauma and accelerated postoperative recovery. Radiotherapy also plays a crucial role in the treatment of esophageal cancer and can be an effective treatment option for patients who are unsuitable for or refuse surgery. Chemotherapy is primarily used in the treatment of esophageal cancer in the neoadjuvant, adjuvant, and palliative forms. Neoadjuvant chemotherapy is chemotherapy given before surgery to reduce tumor size and stage, thereby improving the success rate of surgical resection. Adjuvant chemotherapy is chemotherapy given after surgery to eliminate residual cancer cells and reduce the risk of recurrence and metastasis. Palliative chemotherapy is used for patients with advanced esophageal cancer to relieve symptoms and prolong survival. Targeted therapy is a method of treating esophageal cancer by targeting specific molecular targets. It has been a popular method in recent years. Currently, some targeted drugs have been approved for the clinical treatment of esophageal cancer, mainly including trastuzumab, ramucirumab, nivolumab, etc.

[0004] Despite this, new targeted therapeutic drugs for esophageal cancer are still needed clinically. In view of this, the present application is proposed. SUMMARY OF THE INVENTION

[0006] To address the above issues, the applicant detected SCTAG protein in cancer tissues, adjacent tissues, and normal tissues of esophageal cancer patients through immunohistochemistry and found that SCTAG protein was highly expressed in the tissues of esophageal cancer patients. Further studies revealed that SCTAG overexpression promoted the proliferation of esophageal cancer cells, while knockdown inhibited the proliferation of esophageal cancer cells. Moreover, SCTAG protein could promote the progression of esophageal cancer through EGFR, and that the proliferation and growth of esophageal cancer tumor cells could be effectively inhibited by inhibiting the SCTAG or EGFR signaling pathway, which provides a new approach for the treatment of esophageal cancer.

[0007] Therefore, this application includes at least the following objectives: to seek new therapeutic targets, drug compositions and treatment strategies for esophageal cancer.

[0008] In order to achieve the above-mentioned invention objectives, the technical solutions specifically adopted in this application are as follows:

[0009] In one aspect, the present application first provides the use of SCTAG inhibitors in preventing or treating esophageal cancer;

[0010] In one aspect, the present application also provides the use of an SCTAG inhibitor in the preparation of a medicament for preventing or treating esophageal cancer;

[0011] On the one hand, the present application also provides the use of SCTAG inhibitors in inhibiting esophageal cancer tumor cells in vivo / in vitro;

[0012] In one aspect, the present application also provides the use of an SCTAG inhibitor in the preparation of a drug for inhibiting esophageal cancer tumor cells.

[0013] Furthermore, the SCTAG inhibitor can inhibit the activity, function and / or expression of the SCTAG protein. Therefore, in some aspects, the SCTAG inhibition can be performed at the protein level or at the gene level.

[0014] For example, in some preferred embodiments, the inhibition includes but is not limited to any of the following methods:

[0015] 1) By inhibiting the function or activity of the SCTAG protein itself;

[0016] 2) Interfering with the expression of the SCTAG gene;

[0017] 3) Editing the SCTAG gene;

[0018] 4) interfering with the interaction between SCTAG protein and tumor cell membrane receptor; the tumor cell membrane receptor is a receptor protein expressed on the tumor cell membrane that can bind to SCTAG and exert certain biological functions; more preferably, the receptor protein is EGFR protein.

[0019] Furthermore, the inhibitor may include, but is not limited to, the following types: small molecule inhibitors, polypeptide inhibitors, antibody or antigen-binding fragment inhibitors, or nucleic acid inhibitors.

[0020] In some embodiments, the inhibitor is an antibody, such as a monoclonal antibody, a polyclonal antibody, an antiserum, a chimeric antibody, a humanized antibody, and a human antibody; preferably, the antibody is selected from a multispecific antibody, a single-chain Fv (scFv), a single-chain antibody, an anti-idiotypic (anti-Id) antibody, a diabody, a minibody, a nanobody, a single domain antibody, a Fab fragment, a F(ab') fragment, a disulfide-linked bispecific Fv (sdFv), and an intrabody.

[0021] In some embodiments, the inhibitor is a nucleic acid inhibitor, including a DNA inhibitor or an RNA inhibitor, such as siRNA and RNAi based on RNA interference, or sgRNA and guideDNA based on gene editing.

[0022] In some embodiments, the inhibitor is a nucleic acid inhibitor, including a probe or a primer.

[0023] On the one hand, the present application also provides a compound or antagonist compound, which can downregulate the function or activity of SCTAG protein.

[0024] Furthermore, the inhibiting of esophageal cancer tumor cells at least includes inhibiting the proliferation and growth of esophageal cancer tumor cells.

[0025] In one aspect, the present application also provides a pharmaceutical composition for inhibiting esophageal cancer, wherein the pharmaceutical composition comprises an SCTAG inhibitor.

[0026] Further preferably, the compound includes but is not limited to: small molecule inhibitors, polypeptide inhibitors, antibody or antigen-binding fragment inhibitors or nucleic acid inhibitors.

[0027] In some embodiments, the inhibitor is an antibody, such as a monoclonal antibody, a polyclonal antibody, an antiserum, a chimeric antibody, a humanized antibody, and a human antibody; preferably, the antibody is selected from a multispecific antibody, a single-chain Fv (scFv), a single-chain antibody, an anti-idiotypic (anti-Id) antibody, a diabody, a minibody, a nanobody, a single domain antibody, a Fab fragment, a F(ab') fragment, a disulfide-linked bispecific Fv (sdFv), and an intrabody.

[0028] In some embodiments, the inhibitor is a nucleic acid inhibitor, including a DNA inhibitor or an RNA inhibitor, such as siRNA and RNAi based on RNA interference, or sgRNA and guideDNA based on gene editing.

[0029] Furthermore, the pharmaceutical composition also includes a pharmaceutically acceptable carrier and corresponding pharmaceutical excipients.

[0030] In one aspect, the present application also provides the use of SCTAG protein as an EGFR ligand or agonist.

[0031] Furthermore, when used as a ligand, the use includes use in the preparation of EGFR inhibitors;

[0032] In some embodiments, the inhibition is based on the ligand SCTAG acting as a targeting component to bind to EGFR, and EGFR inhibition is achieved by carrying an inhibitory molecule;

[0033] In some preferred embodiments, the use is in the preparation of EGFR inhibitors for esophageal cancer inhibition or the preparation of esophageal cancer inhibition drugs; the inhibitor is based on the ligand SCTAG as a targeting component to connect to EGFR, and achieves EGFR inhibition by carrying inhibitory molecules, thereby achieving the purpose of esophageal cancer inhibition; more preferably, the inhibitor includes, for example, nuclide drugs or PROTAC drugs.

[0034] In one aspect, the present application also provides a pharmaceutical composition for inhibiting esophageal cancer, wherein the pharmaceutical composition comprises an EGFR inhibitor.

[0035] Furthermore, the EGFR inhibitor is based on the ligand SCTAG as a targeting component to connect to EGFR, and achieves EGFR inhibition by carrying inhibitory molecules.

[0036] In some embodiments, the type of pharmaceutical composition includes but is not limited to: a nuclide drug or a PROTAC drug.

[0037] On the one hand, the present application also provides a method for inhibiting esophageal cancer or esophageal cancer tumor cells in vitro or in vivo, comprising the step of inhibiting SCTAG protein in vitro or in vivo; or the step of inhibiting using any of the aforementioned pharmaceutical compositions.

[0038] In some aspects, inhibiting oncogenic tumor cells includes inhibiting the growth, proliferation, migration, etc. of oncogenic tumor cells.

[0039] In a further preferred embodiment, the inhibition results in the activity, function and / or expression of the SCTAG protein itself being inhibited to varying degrees; or the binding of the SCTAG protein to EGFR is affected.

[0040] In some aspects, the SCTAG inhibition can be performed at the protein level or at the gene level;

[0041] In some embodiments, the inhibition includes but is not limited to any of the following:

[0042] 1) By inhibiting the function or activity of the SCTAG protein itself;

[0043] 2) Interfering with the expression of the SCTAG gene;

[0044] 3) Editing the SCTAG gene;

[0045] 4) interfering with the interaction between SCTAG protein and tumor cell membrane receptor; the tumor cell membrane receptor is a receptor protein expressed on the tumor cell membrane that can bind to SCTAG and exert certain biological functions; more preferably, the receptor protein is EGFR protein.

[0046] In one aspect, the present application also provides a method for preventing or treating esophageal cancer, which comprises the step of administering an effective dose of an SCTAG inhibitor, an EGFR inhibitor, or any of the above pharmaceutical compositions to a subject.

[0047] On the one hand, the present application also provides a method for screening drugs or reagents for preventing or treating esophageal cancer, which method includes screening out compounds that can inhibit the function, activity or expression of SCTAG protein, or screening out compounds that can inhibit the binding of SCTAG protein to EGFR; and then obtaining candidate drugs or reagents; preferably, the compounds include but are not limited to: small molecule inhibitors, polypeptide inhibitors, antibodies or antigen binding fragment inhibitors or nucleic acid inhibitors, etc.

[0048] It will be appreciated that the above is a general description and may contain simplifications, summaries and omissions of details when necessary. Therefore, those skilled in the art will recognize that this general description is merely illustrative and is not intended to be limiting in any way. Other aspects, features and advantages of the methods, compositions and / or devices and / or other themes described herein will become apparent in the teachings shown herein. General descriptions are provided to simplify the concepts of some selections, which will be further described in the detailed description below. The above general descriptions are not intended to determine the key features or essential features of the claimed subject matter, nor are they intended to be used as an auxiliary means for determining the scope of the claimed subject matter. In addition, the contents of all references, patents and published patent applications cited throughout this application are incorporated herein by reference in their entirety. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] Figure 1 , Immunohistochemical detection of the expression level of SCTAG in normal esophageal tissue (left), paracancerous tissue (middle) and cancer tissue (right).

[0051] Figure 2 , Western-Blot was used to detect the expression level of SCTAG in normal esophageal tissue (N) and cancer tissue (T).

[0052] Figure 3 , SCTAG overexpression promotes esophageal cancer cell proliferation results; among them, (A) is qRT-PCR detection of SCTAG mRNA expression in esophageal cancer cells with SCTAG gene overexpression, with GAPDH as the internal reference control; (B) is Western blot detection of SCTAG protein expression in esophageal cancer cells with SCTAG gene overexpression, with GAPDH as the internal reference control; (C) is grayscale value analysis of Figure B; (D) is CCK-8 experiment detection of the effect of SCTAG gene overexpression on esophageal cancer cell proliferation; (E) is EdU cell proliferation experiment verification of the effect of SCTAG gene overexpression on esophageal cancer cell proliferation, scale bar: 50μm, *=p<0.05, ****=p<0.0001, with statistically significant differences.

[0053] Figure 4 , SCTAG knockdown inhibits the proliferation of esophageal cancer cells; among them, (A) is the qRT-PCR detection of the expression of SCTAG mRNA in esophageal cancer cells transfected with si-RNA (si-5, 6, 7, 8), with GAPDH as the internal reference; (B) Western blot detection of the expression of SCTAG protein in esophageal cancer cells transfected with si-7 and si-8, with GAPDH as the loading control; (C) is the grayscale value analysis of Figure B; (D) is the CCK-8 experiment verifying the effect of si-7 and si-8 knockdown of SCTAG on the proliferation of esophageal cancer cells; (E) is the EdU cell proliferation experiment verifying the effect of si-7 and si-8 knockdown of SCTAG on the proliferation of esophageal cancer cells, scale bar: 50μm, *=p<0.05, with statistical significance.

[0054] Figure 5, SCTAG protein promotes esophageal cancer cell metastasis results, among which, (A) is a scratch assay to verify the effect of exogenous SCTAG recombinant protein and / or SCTAG antibody on esophageal cancer cell migration, scale: 100μm; (B) is a Transwell migration assay to verify the effect of exogenous SCTAG recombinant protein or SCTAG antibody on esophageal cancer cell migration, scale: 50μm; (C) is a Transwell invasion assay to verify the effect of exogenous SCTAG recombinant protein or SCTAG antibody on esophageal cancer cell invasion, scale: 50μm, *=p<0.05, with statistical significance.

[0055] Figure 6 In vitro and in vivo experiments analyzed the effects of anti-SCTAG antibodies on the proliferation of esophageal cancer cells. (A) shows the inhibition of esophageal cancer cell line Eca109 by SCTAG antibodies; (B) shows the inhibition of esophageal cancer cell line TE-1 by SCTAG antibodies; (C) shows the tumor growth inhibition results after tumor resection (the first row shows the PBS control group; the second row shows the anti-SCTAG antibody treatment group). (D) shows the changes in subcutaneous tumor volume in tumor-bearing mice after SCTAG antibody treatment (measured once daily).

[0056] Figure 7 The effects of SCTAG and / or cetuximab on the proliferation ability of esophageal cancer cells were investigated in vitro and in vivo. (A) shows the effects of SCTAG and / or cetuximab on the proliferation ability of esophageal cancer cell line Eca109; (B) shows the effects of SCTAG and / or cetuximab on the proliferation ability of esophageal cancer cell line TE-1; (C) shows the gross picture after tumor resection; (D) shows the changes in subcutaneous tumor volume in tumor-bearing mice after treatment with SCTAG and / or cetuximab (measured once a day). Detailed Description of the Invention

[0058] Although the present application can be implemented in many different forms, what is disclosed here is its specific illustrative embodiment that verifies the principle of the present application. It should be emphasized that the present application is not limited to the specific embodiment illustrated. In addition, any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0059] The following terms or definitions are provided merely to aid understanding of the present application. These definitions should not be construed as having a scope less than that understood by those skilled in the art.

[0060] Unless otherwise defined below, the meaning of all technical terms and scientific terms used in the specific embodiments of the present application is intended to be the same as that generally understood by those skilled in the art. Although it is believed that the following terms are well understood by those skilled in the art, the following definitions are still set forth to better explain the present application.

[0061] The terms "comprising," "including," "having," "containing," or "involving" are inclusive or open-ended and do not exclude other unrecited elements or method steps. The term "consisting of" is considered a preferred embodiment of the term "comprising." If a group is defined below as comprising at least a certain number of embodiments, this should also be understood to disclose a group that preferably consists only of these embodiments.

[0062] When referring to a singular noun an indefinite or definite article e.g. "a" or "an", "the" include a plural of that noun.

[0063] Furthermore, the terms first, second, third, (a), (b), (c), and the like, in the specification and claims, are used to distinguish similar elements and are not necessarily intended to describe a sequential or chronological order. It is understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments described herein can be practiced in other sequences than described or illustrated herein.

[0064] The term "and / or" is considered a specific disclosure of each of the two specified features or components with or without the other. Thus, the term "and / or" as used in phrases such as "A and / or B" herein is intended to include A and B; A or B; A (alone); and B (alone). Likewise, the term "and / or" as used in phrases such as "A, B, and / or C" is intended to encompass each of the following: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0065] The terms "such as" and "ie" are used merely as examples and are not intended to be limiting, and should not be construed as referring only to those items explicitly listed in the specification.

[0066] 47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000 or more of the above values. Any larger number or fraction therebetween is also included.

[0067] Conversely, the term "no more than" includes every value that is less than the stated value. For example, "no more than 100 nucleotides" includes 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 56, 57, 58, 59 ... 7, 6, 5, 4, 3, 2, 1, and 0 nucleotides. Also included are any smaller numbers or fractions therebetween.

[0068] The terms "plurality", "at least two", "two or more", "at least a second", etc., should be understood to include, but are not limited to, at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 , 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100 or 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000 or more. Any larger number or fraction therebetween is also included.

[0069] The terms "approximately" and "substantially" represent an accuracy range that can be understood by those skilled in the art and can still ensure the technical effect of the characteristics discussed. This term usually means ±10%, preferably ±5%, of the deviation from the indicated value.

[0070] As used herein, unless otherwise indicated, any concentration range, percentage range, ratio range, or integer range should be understood to include the value of any integer within the recited range, and where appropriate, fractions thereof (e.g., tenths and hundredths of integers).

[0071] Various aspects of the present disclosure are further described in detail

[0072] 1. Use of SCTAG in the inhibition, prevention or treatment of esophageal cancer

[0073] This application proposes for the first time that SCTAG can be used as a target for the treatment of esophageal cancer and can be used to inhibit or treat esophageal cancer.

[0074] The protein "SCTAG," also known as protamine 1 (PRM1) and used interchangeably herein, is a newly discovered cancer-testis antigen (CTA). The SCTAG gene, located on human chromosome 16, is 399 bp long and contains one exon and two introns, encoding a 51-amino acid sequence that is rich in arginine and positively charged. Protamine is the primary DNA-binding protein in the sperm nucleus. During the elongating spermatid stage of spermatogenesis, human sperm chromatin undergoes a complex transformation in which histones are extensively replaced by protamines. This is a carefully regulated process involving histone modifications and intermediate and transient replacement of histones by sperm-specific transition proteins. Replacement of most histones with SCTAG promotes higher-order chromatin packaging, which is essential for normal sperm function. Most patients with abnormal SCTAG levels have elevated protamine transcript levels in mature spermatids, suggesting a possible transcriptional or translational defect. The regulation of SCTAG expression is unique, encompassing multiple potential mechanisms that may contribute to dysregulated SCTAG expression and a broad spectrum of defects in spermatogenesis. However, prior art reports on SCTAG inhibiting esophageal cancer have been lacking. The applicants have experimentally discovered that SCTAG is a specific diagnostic marker for esophageal cancer and can promote its progression. By inhibiting the function, activity, and even expression of the SCTAG protein, SCTAG can inhibit the proliferation and growth of esophageal cancer cells and tissues, potentially potentially leading to its potential use in the treatment of esophageal cancer.

[0075] As used herein, the term "treat" refers to performing any type of intervention or procedure on a subject, or administering an active agent to the subject, for the purpose of reversing, alleviating, ameliorating, inhibiting, slowing down, or preventing the onset, progression, development, severity, or recurrence of a symptom, complication, or condition, or a biochemical marker associated with the disease. In some embodiments, "treat" includes partial remission, such as partial remission of esophageal cancer. In another embodiment, "treat" includes complete remission, such as complete remission of esophageal cancer.

[0076] In this application, the term "inhibition" refers to the inhibition of the activity, function and / or expression of the SCTAG protein itself, or the inhibition of the activity or function of the SCTAG protein binding to other targets, so that the performance is lower than the state before inhibition. The expression, activity, function, etc. of the protein all fall into the category of "inhibition". It can be understood that there are many means to achieve the inhibition of protein activity, function and / or expression, and all means are within the scope of this application. For example, inhibition can be at the protein level, or it can be based on gene-level inhibition to indirectly achieve protein inhibition.

[0077] Inhibition at the protein level. In some embodiments, the inhibition can be achieved by blocking or inhibiting the protein itself or the function of the connection through specific binding to the protein. These specifically binding molecules can include but are not limited to the following types: small molecule inhibitors, polypeptides, antibodies or antigen-binding fragments. For example, specific binding is based on immunosuppressive means, such as by binding of antibodies to SCTAG proteins, thereby inhibiting or blocking the function or activity of the protein. The term "antibody" (Ab) includes but is not limited to glycoprotein immunoglobulins that specifically bind to antigens. Generally, antibodies can comprise at least two heavy (H) chains and two light (L) chains interconnected by disulfide bonds, or antigen-binding molecules thereof. Each H chain comprises a heavy chain variable region (abbreviated herein as VH) and a heavy chain constant region. The heavy chain constant region comprises three constant domains, CH1, CH2 and CH3. Each light chain comprises a light chain variable region (abbreviated herein as VL) and a light chain constant region. The light chain constant region comprises one constant domain, CL. The VH and VL regions can be further subdivided into highly variable regions, called complementarity determining regions (CDRs), interspersed with more conserved regions, called framework regions (FRs). Each VH and VL comprises three CDRs and four FRs, arranged in the following order from amino terminus to carboxyl terminus: FR1, CDR1, FR2, CDR2, FR3, CDR3 and FR4. The variable regions of the heavy and light chains contain binding domains that interact with antigens. The constant region of Ab can mediate the binding of immunoglobulins to host tissues or factors, including various cells of the immune system (e.g., effector cells) and the first component (C1q) of the classical complement system. In some preferred embodiments, the antibodies described in the present application may include, for example: monoclonal antibodies, polyclonal antibodies, antisera, chimeric antibodies, humanized antibodies and human antibodies; more preferably, the antibodies are selected from multispecific antibodies, single-chain Fv (scFv), single-chain antibodies, anti-idiotypic (anti-Id) antibodies, diabodies, miniantibodies, nanoantibodies, single-domain antibodies, Fab fragments, F(ab') fragments, disulfide-linked bispecific Fv (sdFv) and intracellular antibodies.

[0078] Inhibition at the gene level. In some embodiments, the inhibition at the gene level may include means of editing the SCTAG gene, and the gene editing means may include: zinc finger nuclease technology (ZFNs), transcription activator-like effector nuclease technology (TALENs), CRISPR / Cas9 technology, BE (base editing) and PE (prime editing) technology. Zinc finger nuclease technology (ZFNs) and transcription activator-like effector nuclease technology (TALENs) are the earliest artificially synthesized restriction endonucleases used for genome editing. They achieve knockout, insertion or precise modification of specific gene sequences in the genome through specific DNA (such as SCTAG encoding gene) binding domains and FokI nuclease domains that cut DNA. CRISPR / Cas9 technology, also known as "gene magic scissors", is a revolutionary gene editing technology that uses a system composed of CRISPR gene sequences and Cas genes to accurately identify and cut specific DNA sequences (such as SCTAG encoding gene), thereby achieving gene knockout, insertion or point mutation. BE (base editing) and PE (prime editing) technologies are new technologies developed in recent years. BE technology can replace a specific base pair at a specific site with another specified base pair, while PE technology integrates a single-stranded DNA into the genome through the cell's self-repair mechanism, enabling more complex gene editing operations. These methods can achieve the inhibition of target genes and, in turn, the inhibition of corresponding proteins, and are commonly used in the field of gene therapy. Therefore, this application also covers the field of gene therapy.

[0079] In some embodiments, the gene-level inhibition can also be achieved by interfering with the expression of the SCTAG gene level. The means of such gene interference include the use of antisense RNA (siRNA), antisense RNA nucleic acid plus ribozyme, interfering RNA (RNAi), etc. These methods can also be applied to the field of gene therapy, by shutting down or inhibiting the expression of pathogenic genes in a specific way, in order to achieve the purpose of treating the disease. For example, antisense RNA is a single-stranded RNA that can complementarily pair with the target mRNA (such as the mRNA corresponding to SCTAG), and by binding to the mRNA, it prevents it from being translated into protein, thereby inhibiting gene expression. Antisense RNA nucleic acid plus ribozyme combines the technology of antisense RNA, and further enhances the inhibition of gene expression by introducing specific nucleases to cut the target mRNA. Interfering RNA (RNAi) is a double-stranded RNA molecule that can specifically bind to and degrade endogenous mRNA (such as the mRNA corresponding to SCTAG), thereby effectively silencing the expression of specific genes.

[0080] The aforementioned means are merely examples. Any means in the prior art that can achieve SCTAG protein or gene inhibition theoretically falls within the scope of this application, and those skilled in the art can select as needed.

[0081] In addition, the final example of this application also confirms that SCTAG can promote tumor progression by binding to EGFR, proving not only that SCTAG is a ligand for the EGFR receptor on the tumor cell membrane, but also that SCTAG can act as an agonist of EGFR. At the same time, it also proves that EGFR can become a potential target for immunotherapy of esophageal cancer. Therefore, this application also includes at least the following applications and therapeutic applications:

[0082] The application of SCTAG protein as an EGFR ligand, especially in the inhibition or treatment of esophageal cancer. It is understandable that, based on the receptor / ligand relationship, the inhibition can include the ligand SCTAG as a targeting component of EGFR, and the inhibition of EGFR by carrying other inhibitory molecules (such as molecules that can specifically bind to EGFR), thereby achieving the purpose of tumor suppression. There are many types of such drugs in the prior art, such as some common types: nuclide drug compositions or PROTAC drugs.

[0083] 2. SCTAG-based esophageal cancer cell regulation method

[0084] Based on the findings of the present application, the present application also discloses a method for inhibiting the proliferation or growth of esophageal cancer cells in vitro or in vivo. The method is achieved by inhibiting the activity, function and / or expression of the SCTAG protein in vivo or in vitro.

[0085] As used herein, the term "regulate" generally encompasses both upregulation and downregulation. In some cases, it can mean inhibition or enhancement, in some cases, reduction or increase, and in some cases, decrease or increase. The specific meaning is not limited and should be understood and interpreted based on the actual application context. For example, in some embodiments, "regulating" tumor cells can be understood as inhibiting or enhancing tumor cells.

[0086] In further embodiments, such regulation is inhibitory. It is understood that such inhibition may include regulating the proliferation, growth, or even migration of tumor cells, without limitation. It is reasonably anticipated in the art that the inhibitory effects on tumor cell proliferation, growth, or migration, in addition to achieving the goal of alleviating, removing, or treating disease lesions, may also be used for conducting in vitro basic research experiments (such as constructing cell or animal models). These in vitro experiments do not involve the treatment of diseases.

[0087] In some specific inhibition embodiments, the method may include the following basic steps:

[0088] The above purpose is achieved by inhibiting the expression, function or activity of SCTAG in esophageal cancer cells expressing SCTAG.

[0089] Similarly, there are various methods for inhibiting the expression, function, or activity of a specific protein. These methods can be carried out at the protein level or the gene level, which are well known in the art. In some embodiments, the above-mentioned inhibition method can be any of the following:

[0090] a. Perform gene editing on the SCTAG gene to destroy the integrity of the gene, thereby reducing the expression and activity of the gene; in some preferred embodiments, the gene editing system of the present application is a CRISPR / Cas9 gene editing system.

[0091] b. Interfering with SCTAG gene expression, such as RNAi, to reduce the expression or activity of the gene;

[0092] c. Inhibition by immune means, such as inhibiting the function or activity of SCTAG protein through antibodies;

[0093] d. Using non-immune binding methods such as small molecules or peptides that can bind to the SCTAG protein to inhibit the function or activity of the SCTAG protein based on binding;

[0094] e. Interfering with the interaction between SCTAG protein and tumor cell membrane receptor; the tumor cell membrane receptor is a receptor protein expressed on the tumor cell membrane that can bind to SCTAG and exert certain biological functions; in some embodiments, the receptor protein is EGFR protein.

[0095] 3. Inhibitors of the present application and screening of inhibitors thereof

[0096] The present application provides an SCTAG inhibitor that can be used to treat or inhibit esophageal cancer. The inhibitor includes, but is not limited to, small molecule inhibitors, peptide inhibitors, antibody or antigen-binding fragment inhibitors, or nucleic acid inhibitors. The term "inhibitor" as used herein may refer to a protein-level inhibitor or a gene-level inhibitor. Any inhibitor that can inhibit the SCTAG gene or protein, including but not limited to the generation, transcription, activity, and function of the gene, or the expression, activity, and function of the protein, falls within the scope of an "inhibitor."

[0097] Exemplary, when it is a protein-level inhibitor, it is a substance that can bind to the SCTAG protein and inhibit or block the downstream function of SCTAG. In some embodiments, the protein-level inhibitor includes but is not limited to small molecule protein inhibitors, polypeptides, antibodies or antigen-binding fragments.

[0098] When it comes to protein-level inhibition, in some cases, the protein-level inhibitor can specifically and highly affinity bind to the SCTAG protein; in other cases, the protein-level inhibitor can antagonize proteins that function downstream of SCTAG. These proteins can be in the form of peptides, antibodies, antigen-binding fragments, or small molecule inhibitors.

[0099] In some embodiments, the inhibitor is an antibody, which may include, for example, monoclonal antibodies, polyclonal antibodies, antisera, chimeric antibodies, humanized antibodies, and human antibodies; more preferably, the antibody is selected from multispecific antibodies, single-chain Fv (scFv), single-chain antibodies, anti-idiotypic (anti-Id) antibodies, diabodies, miniantibodies, nanoantibodies, single-domain antibodies, Fab fragments, F(ab') fragments, disulfide-linked bispecific Fv (sdFv), and intracellular antibodies. In other embodiments, the inhibitor is a non-antibody polypeptide that can specifically bind to the key site of SCTAG, thereby causing a decrease in the function or activity of the SCTAG protein. In other embodiments, the inhibitor is a small molecule inhibitor, especially a small molecule compound that is not a protein or polypeptide, which causes a decrease in the function or activity of the SCTAG protein by binding to the key site of SCTAG.

[0100] When it is a gene-level inhibitor, as mentioned above, it can be gene editing at the SCTAG gene level, indirectly achieving the inhibition of SCTAG protein activity and function by changing the activity or function of the SCTAG gene; or indirectly achieving the inhibition of SCTAG protein activity and function by interfering with the expression of the SCTAG gene. In some embodiments, the gene editing may include: zinc finger nuclease technology (ZFNs), transcription activator-like effector nuclease technology (TALENs), CRISPR / Cas9 technology, BE (base editing) and PE (prime editing) technology, etc., and the corresponding inhibitors may be nucleic acid inhibitors such as sgRNA and guideRNA. In other embodiments, the means of interfering with the expression of the SCTAG gene include antisense RNA (siRNA), antisense RNA nucleic acid plus ribozyme, interfering RNA (RNAi), etc.; the corresponding inhibitors include siRNA or RNAi, etc.

[0101] The above-mentioned inhibitors can be prepared into corresponding pharmaceutical compositions by operations known in the art.

[0102] Similarly, since the present application also confirms that SCTAG is a ligand of the tumor cell membrane receptor EGFR and that SCTAG can act as an agonist of EGFR, the present application may also relate to another type of inhibitor, which is an EGFR inhibitor.

[0103] In some embodiments, the EGFR inhibitor includes a ligand-based SCTAG as a targeting component for EGFR, which inhibits EGFR by carrying other inhibitory molecules (such as molecules that can specifically bind to EGFR), thereby achieving the purpose of inhibiting or treating esophageal cancer. There are many types of such inhibitors in the prior art, such as some common types: radionuclide drug compositions or PROTAC drugs.

[0104] The present application also provides a method for screening or identifying candidate inhibitors, which may include the following steps:

[0105] First, a candidate compound is obtained and added to the SCTAG protein to analyze the effect of the candidate compound on the function, activity or expression of the SCTAG protein, or on the binding activity of the SCTAG protein with EGFR. When the corresponding effect is found, it is concluded that the candidate compound can be used as a candidate inhibitor, and further experimental evaluation is performed.

[0106] 4. Pharmaceutical compositions of the present application

[0107] The pharmaceutical composition of the present application comprises any of the aforementioned SCTAG inhibitors or EGFR inhibitors. For example, in some embodiments, the pharmaceutical composition of the present application is a pharmaceutical composition comprising the aforementioned antibody or antigen-binding fragment; in other embodiments, the pharmaceutical composition of the present application is a polypeptide pharmaceutical composition comprising the aforementioned inhibitory polypeptide; in other embodiments, the pharmaceutical composition of the present application is a chemical pharmaceutical composition comprising the aforementioned small chemical molecule; in other embodiments, the pharmaceutical composition of the present application is an RNA pharmaceutical composition comprising the aforementioned RNA inhibitor; in some embodiments, the pharmaceutical composition of the present application is a DNA pharmaceutical composition comprising the aforementioned DNA inhibitor; in some embodiments, the pharmaceutical composition of the present application is a nuclide pharmaceutical composition; in some embodiments, the pharmaceutical composition of the present application is a PROTAC pharmaceutical composition.

[0108] The pharmaceutical composition of the present application may contain not only a specific inhibitor (including an SCTAG inhibitor or an EGFR inhibitor), but also a combination of one or more other therapeutic agents to achieve the effect of combined medication.

[0109] It is understood that the pharmaceutical composition described in the present application may contain corresponding pharmaceutically acceptable carriers depending on the type or type.

[0110] As used herein, the term "pharmaceutically acceptable" refers to a carrier, diluent, excipient, and / or salt thereof that is chemically and / or physically compatible with the other ingredients in the formulation and physiologically compatible with the recipient. As used herein, the term "pharmaceutically acceptable carrier and / or excipient" refers to a carrier and / or excipient that is pharmacologically and / or physiologically compatible with the subject and the active agent, which is well known in the art (see, for example, Remington's Pharmaceutical Sciences. Edited by Gennaro AR, 19th ed. Pennsylvania: Mack Publishing Company, 1995), and includes, but is not limited to, pH regulators, surfactants, adjuvants, and ionic strength enhancers. For example, pH regulators include, but are not limited to, phosphate buffers; surfactants include, but are not limited to, cationic, anionic, or nonionic surfactants, such as Tween-80; and ionic strength enhancers include, but are not limited to, sodium chloride.

[0111] The pharmaceutical composition or pharmaceutical preparation of the present application may also include suitable pharmaceutical excipients, such as pharmaceutical carriers and pharmaceutical excipients as known in the art, including buffers. As used herein, "pharmaceutical carrier" includes any and all solvents, dispersion media, isotonic agents and absorption delay agents that are physiologically compatible. Pharmaceutical carriers suitable for the present application can be sterile liquids, such as water and oils, including those of petroleum, animal, plant or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil, etc. When the pharmaceutical composition is administered intravenously, water is a preferred carrier. Saline solutions and aqueous dextrose and glycerol solutions can also be used as liquid carriers, particularly for injectable solutions. Suitable excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol, etc. For the use of excipients and their applications, see also "Handbook of Pharmaceutical Excipients", Fifth Edition, R.C. Rowe, P.J. Seskey and S.C. Owen, Pharmaceutical Press, London, Chicago. If desired, the composition may also contain a small amount of a wetting agent or emulsifier, or a pH buffer. These compositions may take the form of solutions, suspensions, emulsions, tablets, pills, capsules, powders, sustained-release formulations, and the like. Oral formulations may contain standard pharmaceutical carriers and / or excipients, such as pharmaceutical grade mannitol, lactose, starch, magnesium stearate, saccharin. In addition, pharmaceutical formulations containing the SCTAG inhibitors described herein may also be prepared by mixing the SCTAG inhibitors of the present application having the desired purity with one or more optional pharmaceutical excipients, preferably in the form of a lyophilized formulation or an aqueous solution.

[0112] 5. The preventive or therapeutic methods of this application

[0113] The present application provides a method for preventing or treating esophageal cancer in a subject, comprising administering to the subject an effective dose of an SCTAG inhibitor or pharmaceutical composition of the present application; or administering to the subject an effective dose of an EGFR inhibitor or pharmaceutical composition of the present application.

[0114] The administration of the preventive agent can be administered before the onset of symptoms in order to prevent the occurrence of the disease, or alternatively to delay the progression of the disease. The present application also provides a method for alleviating or treating esophageal cancer subjects, comprising administering to the subject an effective dose of the SCTAG inhibitor or pharmaceutical composition of the present application. The administration of the therapeutic agent can be administered after the onset of symptoms. Preferably, the subject has received, is receiving, or will receive additional anti-cancer therapy; more preferably, the additional anti-cancer therapy includes surgery, radiotherapy, chemotherapy, immunotherapy, or hormone therapy.

[0115] As used herein, an "effective dose" is any amount that, when used alone or in combination with another therapeutic agent, protects a subject from the onset of disease or promotes disease regression, as evidenced by a decrease in the severity of disease symptoms, an increase in the frequency and duration of disease-free periods, or prevention of impairment or disability due to disease affliction. The ability of a therapeutic agent to promote disease regression can be assessed using various methods known to skilled practitioners, for example, in human subjects during clinical trials, in animal model systems used to predict efficacy in humans, or by measuring the activity of the agent in an in vitro assay.

[0116] As used herein, an "individual" or "subject" is a mammal. Mammals include primates (e.g., humans and non-human primates such as monkeys) and rodents (e.g., mice and rats). In certain embodiments, the individual or subject is a human. A "subject" can be a "patient," which is a human subject in need of treatment, and can be an individual with esophageal cancer or an individual at risk of developing esophageal cancer. Example

[0117] The experimental methods in the following examples are conventional methods unless otherwise specified. The present application will be further understood with reference to the following non-limiting experimental examples.

[0118] The samples and clinical data involved in this embodiment were collected as follows.

[0119] Tissues: Tissue samples from 90 esophageal cancer patients were obtained from the Tissue Specimen Bank of Jilin University Third Hospital and the First Hospital of Jilin University. Tissue samples from each patient included tumor tissue, adjacent paracancerous tissue (2-5 cm from the tumor), and normal tissue (>5 cm from the tumor) for total protein and mRNA extraction.

[0120] Serum: Preoperative serum samples from 244 esophageal cancer patients and 220 healthy subjects were obtained from the tissue specimen banks of Jilin University Third Hospital and Jilin University First Hospital. In addition, serum samples were collected from 59 patients undergoing esophageal cancer surgery before surgery and on days 3 and 8 after surgery. All serum samples were collected from venous blood in the early morning, fasting state, using EDTA-anticoagulant tubes. These serum samples were used for enzyme-linked immunosorbent assays.

[0121] Pathological sections: The study obtained pathological sections of tumor tissues from 68 patients with esophageal cancer, as well as corresponding pathological sections of adjacent cancer tissues and normal esophageal tissues from the Department of Pathology of the Third Hospital of Jilin University.

[0122] Clinical and pathological data were also collected, including age, sex, tumor location, gross tumor type, degree of tumor differentiation, depth of invasion, presence of lymph node metastasis, presence of vascular and neural invasion, 5-year survival rate, short-term recurrence rate of esophageal cancer (recurrence criteria: non-surgical hoarseness, mediastinal lymphadenopathy, distant metastasis within 1 year), and expression of conventional tumor markers such as CEA, AFP, CA199, and CA724. TNM staging of esophageal cancer was determined according to the 8th edition of the UICC / AJCC TNM staging guidelines for esophageal cancer.

[0123] Example 1: Immunohistochemical detection of SCTAG protein expression in esophageal cancer tissues

[0124] In this example, 68 paraffin tissue sections of esophageal cancer were collected, and para-cancer tissue and normal esophageal mucosal tissue from the same patients were used as controls. Immunohistochemical staining showed that SCTAG protein was widely expressed in esophageal cancer tissue, and positive staining of SCTAG protein was observed in the cytoplasm of esophageal cancer cells. SCTAG was also expressed in para-cancer tissue of esophageal cancer, but the expression intensity was significantly lower than that in cancer tissue. SCTAG was rarely expressed or not expressed in normal tissue, such as Figure 1 As shown in Figure 3, SCTAG is expressed at the highest level in esophageal cancer tissues and is highly specific.

[0125] Example 2: Western-Blot detection of SCTAG protein expression in esophageal cancer tissue

[0126] In this example, fresh esophageal cancer tissue was collected and normal esophageal mucosa tissue from the same patient was used as a control. Western-Blot showed that the expression of SCTAG protein in esophageal cancer tissue was significantly higher than that in the corresponding normal tissue. In normal esophageal cancer mucosa tissue, SCTAG was also expressed in some normal tissues, but the expression intensity was significantly lower than that in cancer tissue. Figure 2 shown.

[0127] Based on the abnormal expression of SCTAG during the development and progression of esophageal cancer and its important biological functions, the applicant conducted a series of subsequent studies on tumor cell proliferation and metastasis to confirm whether SCTAG can be used as an effective therapeutic target for esophageal cancer.

[0128] Example 3: SCTAG overexpression promotes esophageal cancer cell proliferation

[0129] In this example, the SCTAG gene was overexpressed in esophageal cancer cells to explore the effect of SCTAG on the proliferation of esophageal cancer cells. Specifically, a pcDNA3.3 plasmid containing the SCTAG gene was constructed and transfected into esophageal cancer cells. After verifying the transfection efficiency by qRT-PCR and WB, it was found that after the SCTAG gene was overexpressed, the mRNA and protein expression levels of SCTAG were significantly upregulated ( Figure 3 AC); The results of CCK-8 cell viability assay and EdU cell proliferation assay showed that overexpression of SCTAG gene could promote the proliferation activity of esophageal cancer cells compared with cells transfected with empty plasmid vector ( Figure 3 DE).

[0130] Example 4: SCTAG knockdown inhibits esophageal cancer cell proliferation

[0131] Overexpression of SCTAG can promote the proliferation of esophageal cancer cells. Next, the gene knockdown of SCTAG was performed on esophageal cancer cells to observe its effect on proliferation. Four siRNAs (si-5, 6, 7, 8) that knock down the SCTAG gene and a blank control si-RNA (si-NC) were constructed. First, these four si-RNAs were transfected into esophageal cancer cells respectively, and the gene knockdown levels of SCTAG by these si-RNAs were detected by qRT-PCR. The results showed that in esophageal cancer cells, compared with the si-NC control group, si-7 and si-8 had the highest knockdown efficiency ( Figure 4 A). si-7 and si-8 were subsequently used to verify the effect of SCTAG knockdown on esophageal cancer cell proliferation. After multiple WB tests to verify the efficiency of SCTAG knockdown, it was found that compared with the control group transfected with si-NC, the SCTAG protein expression level of esophageal cancer cells knocked down by si-7 and si-8 was significantly reduced ( Figure 4 BC). The results of CCK-8 cell viability experiments and EdU cell proliferation experiments at different time points showed that the proliferation effect of esophageal cancer cells knocked down the SCTAG gene using si-7 and si-8 was significantly weakened ( Figure 4 DE). In summary, knockdown of the SCTAG gene can inhibit the proliferation of esophageal cancer cells.

[0132] Example 5: SCTAG protein promotes esophageal cancer cell metastasis

[0133] This example uses a wound healing assay to verify the effect of exogenous SCTAG protein on the migration efficiency of esophageal cancer cells. After wound healing, the esophageal cancer cell line was stimulated with 2000 pg / mL of exogenous SCTAG recombinant protein or / and 80 ng / mL of SCTAG antibody (αPRM1). The results of the wound healing assay showed that exogenous SCTAG protein can significantly promote the migration of esophageal cancer cells, while SCTAG antibody can inhibit the migration of esophageal cancer cells ( Figure 5 A). In addition, the effect of SCTAG protein on esophageal cancer cell migration was verified by Transwell migration assay. The results showed that esophageal cancer cells stimulated by exogenous SCTAG protein were more likely to pass through the Transwell chamber, and SCTAG antibody could inhibit the migration of esophageal cancer cells through the Transwell chamber ( Figure 5 B). Next, diluted matrigel was spread on the bottom of the Transwell chamber to simulate the tumor basement membrane, and the effect of SCTAG on the invasion ability of esophageal cancer cells was observed. The results showed that SCTAG protein helped esophageal cancer cells break through the matrigel and achieve distant metastasis, while SCTAG antibody could inhibit esophageal cancer cells from breaking through the matrigel. Figure 5 C) This indicates that exogenous SCTAG protein can promote the migration and invasion of esophageal cancer cells.

[0134] Example 6: Effect of anti-SCTAG antibodies on the proliferation / growth ability of esophageal cancer cells

[0135] This example uses in vivo and in vitro experiments to explore the effect of anti-SCTAGD protein antibodies on the proliferation activity of esophageal cancer cells, providing a theoretical basis for SCTAG to become a new target for immunotherapy of esophageal cancer.

[0136] First, through cytological experiments, anti-SCTAG antibodies were added to the culture medium of esophageal cancer cell lines Eca-109 and TE-1, and their effect on cell proliferation was assessed using the CCK-8 assay. Subsequently, a subcutaneous xenograft model of Eca-109 esophageal cancer in mice was established to further investigate the effect of anti-SCTAG antibodies on esophageal cancer cell proliferation. Tumor-bearing mice were randomly divided into a control group and an anti-SCTAG antibody-treated group. Tumor volume was measured daily, and tumor growth curves were plotted.

[0137] The results showed that anti-SCTAG antibodies could reduce the proliferation of esophageal cancer cells in both in vivo and in vitro experiments ( Figure 6 AB), and tumor growth was significantly inhibited ( Figure 6 CD). This suggests that SCTAG can be a potential target for immunotherapy of esophageal cancer, and anti-SCTAG antibody treatment can effectively inhibit the progression of esophageal cancer.

[0138] Example 4: SCTAG promotes the proliferation of esophageal cancer cells, and blocking EGFR inhibits the proliferation / growth ability of esophageal cancer cells

[0139] To explore the biological function of SCTAG in the development and progression of esophageal cancer, this example uses in vivo and in vitro experiments to explore the effect of SCTAG on the proliferation of esophageal cancer cells. In addition, this application also uses TurboID proximity labeling technology to identify that the cell membrane receptor that interacts with the secretory protein SCTAG may be EGFR. Therefore, this example further studies the effect of blocking EGFR on the proliferation of esophageal cancer cells, providing a theoretical basis for SCTAG to become a new target for immunotherapy of esophageal cancer.

[0140] First, through cytological experiments, the effects of exogenous SCTAG protein, cetuximab, and exogenous SCTAG protein plus cetuximab on cell proliferation were assessed using the CCK-8 assay. Subsequently, a subcutaneous xenograft model of Eca-109 esophageal cancer was established in mice to further investigate the effects of SCTAG protein and / or cetuximab on esophageal cancer cell proliferation. Tumor-bearing mice were randomly divided into a control group, an SCTAG protein group, a cetuximab-treated group, and a SCTAG protein plus cetuximab group. Tumor volume was measured daily, and tumor growth curves were plotted.

[0141] The results showed that SCTAG protein was Figure 7 AB) and in vitro experiments ( Figure 7 SCTAG can promote the proliferation of esophageal cancer cells. After blocking EGFR with cetuximab, the proliferation of esophageal cancer cells was inhibited. When EGFR was blocked, SCTAG no longer promoted the proliferation of esophageal cancer cells. This suggests that EGFR can be a potential target for immunotherapy of esophageal cancer, and SCTAG can promote the progression of esophageal cancer through the cell membrane receptor EGFR.

[0142] The foregoing descriptions of specific exemplary embodiments of the present application are for purposes of illustration and description. These descriptions are not intended to limit the present application to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the present application and their practical application, thereby enabling those skilled in the art to realize and utilize the various exemplary embodiments of the present application and various options and modifications. The scope of the present application is intended to be defined by the claims and their equivalents.

Claims

1. Any of the following uses of SCTAG inhibitors: a) Use in preventing or treating esophageal cancer; b) use in the preparation of a medicament for preventing or treating esophageal cancer; c) Use in inhibiting esophageal cancer tumor cells in vivo / in vitro; d) Use in the preparation of drugs for inhibiting esophageal cancer tumor cells.

2. The use according to claim 1, characterized in that The SCTAG inhibitor results in inhibition of the activity, function and / or expression of the SCTAG protein.

3. The use according to any one of claims 1-2, characterized in that: The SCTAG inhibition is performed at the protein or gene level; preferably, the inhibition includes but is not limited to any of the following methods: a) inhibiting the function or activity of the SCTAG protein itself; b) interfere with the expression of SCTAG gene; c) Editing the SCTAG gene; d) interfering with the interaction between SCTAG protein and tumor cell membrane receptor; preferably, the tumor cell membrane receptor is a receptor protein expressed on the tumor cell membrane that can bind to SCTAG and exert a certain biological function; more preferably, the receptor protein is EGFR protein.

4. The use according to any one of claims 1 to 3, characterized in that: The inhibitor includes but is not limited to: small molecule inhibitors, polypeptide inhibitors, antibody or antigen binding fragment inhibitors or nucleic acid inhibitors; preferably, the antibody or antigen binding fragment inhibitor includes but is not limited to: monoclonal antibodies, polyclonal antibodies, antisera, chimeric antibodies, humanized antibodies and human antibodies; further preferably, the antibody is selected from multispecific antibodies, single-chain Fv (scFv), single-chain antibodies, anti-idiotypic (anti-Id) antibodies, double antibodies, mini antibodies, nano antibodies, single domain antibodies, Fab fragments, F (ab') fragments, disulfide-linked bispecific Fv (sdFv) and intracellular antibodies; preferably, the nucleic acid inhibitor includes but is not limited to: siRNA, RNAi, sgRNA, guideDNA, probes or primers.

5. A pharmaceutical composition for inhibiting esophageal cancer, characterized in that: The pharmaceutical composition comprises an SCTAG inhibitor; the SCTAG inhibitor causes the activity, function and / or expression of the SCTAG protein to be inhibited; preferably, the compound includes but is not limited to: a small molecule inhibitor, a polypeptide inhibitor, an antibody or antigen binding fragment inhibitor or a nucleic acid inhibitor; preferably, the inhibitor is an antibody; more preferably, the antibody is selected from a monoclonal antibody, a polyclonal antibody, an antiserum, a chimeric antibody, a humanized antibody and a human antibody; further preferably, the antibody is selected from a multispecific antibody, a single-chain Fv (scFv), a single-chain antibody, an anti-idiotypic (anti-Id) antibody, a diabody, a minibody, a nanobody, a single domain antibody, a Fab fragment, a F(ab') fragment, a disulfide-linked bispecific Fv (sdFv) and an intracellular antibody; preferably, the nucleic acid inhibitor includes but is not limited to: siRNA, RNAi, sgRNA, guideDNA, a probe or a primer.

6. Use of SCTAG protein as EGFR protein ligand.

7. The use according to claim 6, characterized in that The use is in the preparation of EGFR inhibitors; Preferably, the method is used in the preparation of EGFR inhibitors for esophageal cancer inhibition or in the preparation of esophageal cancer inhibition drugs; more preferably, the inhibition is based on the ligand SCTAG as a targeting component to connect EGFR, and EGFR inhibition is achieved by carrying inhibitory molecules, thereby achieving the purpose of esophageal cancer inhibition.

8. A pharmaceutical composition for inhibiting esophageal cancer, characterized in that: The pharmaceutical composition comprises an EGFR inhibitor; preferably, the EGFR inhibitor is based on the ligand SCTAG as a targeting component to connect to EGFR, and achieves EGFR inhibition by carrying an inhibitory molecule; more preferably, the type of the pharmaceutical composition includes but is not limited to: a nuclear drug or a PROTAC drug.

9. A method for inhibiting esophageal cancer or esophageal cancer tumor cells in vitro / in vivo, characterized in that: The method comprises the steps of inhibiting the activity, function and / or expression of the SCTAG protein in vitro or in vivo, or using any pharmaceutical composition of claim 5 or 8 for inhibition.

10. A method for preventing or treating esophageal cancer, characterized in that: The method comprises the steps of administering an effective dose of a SCTAG inhibitor to a subject; or administering an effective dose of the pharmaceutical composition according to claim 5 or 6 to a subject.

11. A method for screening drugs or agents for preventing or treating esophageal cancer, characterized in that: The method includes screening out compounds that can inhibit the function, activity or expression of SCTAG protein; or screening out compounds that can inhibit the binding of SCTAG protein to EGFR, thereby obtaining candidate drugs or reagents; preferably, the compounds include but are not limited to: small molecule inhibitors, polypeptide inhibitors, antibody or antigen binding fragment inhibitors or nucleic acid inhibitors.

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