Use of MEF2A as a marker for predicting sensitivity of colorectal cancer patients to oxaliplatin treatment

Abstract

The application provides application of MEF2A as a marker for predicting sensitivity of a colorectal cancer patient to oxaliplatin treatment. The application proves through a series of experiments that MEF2A can be used as a new detection marker for predicting sensitivity of a colorectal cancer patient to oxaliplatin treatment or predicting survival rate of the colorectal cancer patient, and that a reagent for inhibiting MEF2A expression such as metformin can effectively improve sensitivity of an oxaliplatin-resistant cell to oxaliplatin, so that oxaliplatin has stronger killing ability to the drug-resistant colorectal cancer cell, and therefore the reagent for inhibiting MEF2A expression such as metformin combined with oxaliplatin can become a new treatment scheme for a colorectal cancer patient with oxaliplatin resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological medicine, in particular to application of MEF2A as a marker for predicting sensitivity of colorectal cancer patients to oxaliplatin treatment. BACKGROUND

[0002] Colorectal cancer (CRC) is the most common malignant tumor of the digestive system. According to the latest global cancer data released by the International Agency for Research on Cancer (IARC) of the World Health Organization in 2020, the global incidence of colorectal cancer ranks third, and the mortality rate ranks second. Low early diagnosis rate and chemotherapy resistance are still the main factors that are not conducive to the long-term prognosis of colorectal cancer patients. The 5-year survival rate of stage I colorectal cancer is more than 90%, while the 5-year survival rate of stage IV colorectal cancer patients is only about 10%. At present, the main treatment for colorectal cancer in clinical treatment is still surgery combined with chemotherapy, and the conventional chemotherapy regimen is usually FOLFOXIRI (5-fluorouracil or capecitabine, leucovorin calcium combined with irinotecan, oxaliplatin). Although the survival rate of patients has improved, chemotherapy resistance still seriously affects the long-term prognosis of colorectal cancer patients.

[0003] Oxaliplatin is one of the most commonly used chemotherapy drugs after surgical resection of colorectal cancer, especially for patients in stage II and III. Oxaliplatin causes the formation of intra- and inter-strand DNA-platinum complexes, which then inhibit gene transcription by sequestering transcription factors or cause G2 / M arrest. In addition, the apoptosis cascade initiated by oxaliplatin is characterized by Bax translocation to mitochondria, release of cytochrome c into the cytoplasm, and activation of caspase 3. Unfortunately, de novo and acquired oxaliplatin resistance remains a major challenge in the treatment of colorectal cancer. The development of drug resistance is multifactorial, including: upregulation of ATP-binding cassette transporters (reducing drug efflux), hyperactive DNA damage response, enhanced anti-apoptosis, and epithelial-to-mesenchymal transition (EMT). Therefore, it is urgent to find a detection marker for oxaliplatin resistance in order to better guide clinical treatment and propose innovative treatment plans targeting the detection marker. SUMMARY

[0004] The present application provides a use of a detection agent for MEF2A expression level in the preparation of a product for predicting the sensitivity of colorectal cancer patients to oxaliplatin treatment or predicting the survival rate of colorectal cancer patients, which aims to better guide the clinical treatment of colorectal cancer and improve the efficiency of treatment.

[0005] Preferably, the detection agent detects at the nucleic acid level.

[0006] Preferably, the detection agent is used to perform any one of the following methods:

[0007] Polymerase chain reaction, denaturing gradient gel electrophoresis, nucleic acid sequencing, microarray analysis, denaturing high performance liquid chromatography, in situ hybridization, and mass spectrometry.

[0008] Preferably, the detection agent comprises a PCR primer.

[0009] Preferably, the detection agent detects at the protein level.

[0010] Preferably, the detection agent is used to perform any one of the following methods:

[0011] Mass spectrometry, amino acid sequencing, electrophoresis, immunoblotting, immunoprecipitation, and immunohistochemistry.

[0012] Preferably, the detection agent comprises an antibody specific for MEF2A protein.

[0013] The present application also provides use of an expression inhibitor targeting MEF2A in the preparation of a product for improving the sensitivity of a colorectal cancer patient to oxaliplatin treatment or inhibiting the proliferation of oxaliplatin-resistant colorectal cancer cells.

[0014] Preferably, the expression inhibitor is siRNA, shRNA, or metformin targeting MEF2A.

[0015] The present application also provides a method for preparing an oxaliplatin-resistant colorectal cancer cell line, comprising the step of overexpressing MEF2A gene in colorectal cancer cells.

[0016] The above-mentioned scheme of the present application has the following beneficial effects:

[0017] The present application found that MEF2A is more highly expressed in colorectal cancer post-chemotherapy recurrence lesions through RNAseq analysis, and found that the expression of MEF2A in oxaliplatin-resistant strains (HCT116 / L) is significantly higher than that in parent strains through in vitro experiments, proving that MEF2A can be used as a new detection marker for oxaliplatin chemotherapy resistance in colorectal cancer, for predicting the sensitivity of colorectal cancer patients to oxaliplatin treatment and predicting the survival rate of colorectal cancer patients. In this way, the clinical treatment of colorectal cancer can be better guided, and the efficiency of treatment can be improved. Further, metformin was found to inhibit the proliferation of MEF2A-high-expressing colorectal cancer cells through drug library screening, and in vitro and animal experiments proved that expression inhibitors targeting MEF2A such as metformin can improve the sensitivity of colorectal cancer patients to oxaliplatin treatment and inhibit the proliferation of oxaliplatin-resistant colorectal cancer cells, and therefore can be used in combination with oxaliplatin as a new treatment regimen for oxaliplatin-resistant colorectal cancer patients.

[0018] Other beneficial effects of the present application will be described in detail in the subsequent specific embodiments section. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Figure for RNAseq analysis results of primary colorectal cancer and recurrence tissue after oxaliplatin chemotherapy of colorectal cancer of the present application, wherein a is the comparison of MEF2A expression level of primary tissue (No Recurrence) and recurrence tissue (Recurrence), b is the comparison of MEF2A expression level of survival group (survive) and death group (death), c is the comparison of MEF2A expression level of well differentiated group (WD), moderately differentiated group (MD) and poorly differentiated group (PD);

[0020] Figure 2 Figure for electrophoresis comparison of MEF2A expression level difference in HCT116 (oxaliplatin parent strain) and HCT116 / L (oxaliplatin drug-resistant strain) of the present application;

[0021] Figure 3 Figure for correlation analysis results of MEF2A expression and lymph node metastasis of colorectal cancer of the present application, wherein N0 represents that the patient's tumor has not yet appeared lymph node metastasis, N1 represents that the patient's tumor has appeared lymph node metastasis, but the number is small, N2 represents that the patient's tumor has appeared lymph node metastasis in the local and surrounding, and the number is large;

[0022] Figure 4 Figure for ROC curve of MEF2A predicting survival rate of colorectal cancer patients of the present application;

[0023] Figure 5 Figure for CCK8 screening of MEF2A targeted drugs using FDA approved drug library (FDA drug library) and by constructing MEF2A stable overexpression colorectal cancer cell line (HCT116-MEF2A) of the present application;

[0024] Figure 6 Drug screening heat map for CCK8 screening of MEF2A targeted drugs by FDA drug library of the present application;

[0025] Figure 7 Figure for CCK8 experiment results of testing the effect of metformin (MTF) on MEF2A overexpressing colorectal cancer cell line of the present application, wherein Vec represents a conventional colorectal cancer cell line, OE MEF2A represents a colorectal cancer cell line overexpressing MEF2A, Vec+MTF represents the addition of metformin in a conventional colorectal cancer cell line, and OE MEF2A+MTF represents the addition of metformin in a colorectal cancer cell line overexpressing MEF2A;

[0026] Figure 8Figure of plate clone experiment results of the effect of metformin on the colorectal cancer cell line overexpressing MEF2A according to the present application;

[0027] Figure 9 Figure of comparative results of MEF2A expression in HCT8, SW480 and HCT116 cell lines inhibited by different concentrations of metformin according to the present application;

[0028] Figure 10 Figure of plate clone experiment results of HCT116 (oxaliplatin parent strain) and HCT116 / L (oxaliplatin drug-resistant strain) when using oxaliplatin (OXA) and metformin alone or in combination according to the present application. DETAILED DESCRIPTION

[0029] In order to make the technical problems solved by the present application, the technical solutions and advantages clearer, the following will be described in detail with reference to the drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0030] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be a locking connection, or a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0033] The application provides application of a detection agent for MEF2A expression level in preparation of a product for predicting sensitivity of a colorectal cancer patient to oxaliplatin treatment or predicting survival rate of the colorectal cancer patient.

[0034] Myocyte Enhancer Factor 2 (MEF2) belongs to the MADS family and is a transcription factor family related to calcium-dependent signal pathways. In vertebrates, the MEF2 gene family consists of four genes, namely MEF2A, MEF2B, MEF2C and MEF2D. The N-terminal of MEF2 is a DNA-binding MADS domain and a MEF2 central domain, and the two domains are mainly used to recruit co-regulators and have high conservation; the C-terminal is a transcriptionally active domain, and the region is less conserved and is the reason for the functional differences of the four genes. MEF2 is highly expressed during embryonic development and is involved in the terminal differentiation of muscle cells and neurons.

[0035] The applicant finds that MEF2A is more highly expressed in a colorectal cancer recurrence after chemotherapy through RNAseq analysis, and finds that the expression of MEF2A in an oxaliplatin-resistant strain (HCT116 / L) is significantly higher than that in a parent strain through an in vitro experiment, proving that MEF2A can be used as a new detection marker for colorectal cancer oxaliplatin chemotherapy resistance, for predicting sensitivity of a colorectal cancer patient to oxaliplatin treatment and predicting survival rate of the colorectal cancer patient. Thus, the clinical treatment of colorectal cancer can be better guided, and the efficiency of treatment can be improved.

[0036] The term "marker" or "detection marker" as used herein refers to a molecule to be used as a target for analyzing an experimental sample of a patient.

[0037] In some embodiments, the detection agent described above detects at the nucleic acid level. For example, it is known to those skilled in the art that the expression level of MEF2A can be detected by detecting the mRNA level corresponding to MEF2A.

[0038] As is apparent to those skilled in the art, the detection of mRNA should not be interpreted as being limited to a specific mRNA sequence directly transcribed from the above-mentioned gene, for example, as a result of alternative mRNA variants, short chains or pre-mRNA processing. The nucleotide sequence of the variant has 95%, 96%, 97%, 98%, 99% or higher identity with the corresponding marker sequence; the short chain can also be qualified as long as it can represent the specific sequence of the full-length mRNA itself. Obviously, the detection of mRNA level can also be carried out by detecting cDNA.

[0039] In some embodiments, the detection agent described above is used to perform any one of the following methods:

[0040] Polymerase chain reaction, denaturing gradient gel electrophoresis, nucleic acid sequencing, microarray analysis, denaturing high performance liquid chromatography, in situ hybridization, and mass spectrometry. It is understood that the methods are not limited to these, and that other methods known to those skilled in the art that are capable of detecting the level of MEF2A expression can be used.

[0041] In some embodiments, where the level of MEF2A expression is detected, for example, by polymerase chain reaction, the detection agent can comprise specific PCR primers, etc.

[0042] As used herein, "primer" refers to a polynucleotide fragment, usually an oligonucleotide, such as a polynucleotide fragment of at least 5 bases, e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35, 40, 45, 50 or more bases, used to amplify a target nucleic acid in a PCR reaction.

[0043] In some embodiments, the detection agent detects at the protein level.

[0044] Proteins or polypeptides used as markers in the present application are intended to include naturally occurring variants of the protein as well as fragments of the protein or variants thereof, particularly immunologically detectable fragments. Immunologically detectable fragments preferably comprise at least 5, 6, 7, 8, 9, 10, 11, 12, 15 or 20 contiguous amino acids of the marker polypeptide. Those skilled in the art will recognize that proteins released by cells or present in the extracellular matrix can be damaged (e.g., during an inflammatory process) and can be degraded or cleaved into such fragments. Certain markers are synthesized in an inactive form, which can be subsequently activated by proteolysis. As will be apparent to the skilled artisan, mRNA, proteins or fragments thereof can also be present as part of a complex. Such complexes can also be used as markers in the sense of the present application. In addition, or in the alternative, the marker polypeptide or variants thereof can carry post-translational modifications, non-limiting examples of which are glycosylation, acylation and / or phosphorylation.

[0045] In some embodiments, the detection agent is used to perform any one of the following methods:

[0046] Mass spectrometry, amino acid sequencing, electrophoresis, immunoblotting, immunoprecipitation, and immunohistochemistry. It is understood that the methods are not limited to these, and that other methods known to those skilled in the art that are capable of detecting the level of MEF2A expression can be used.

[0047] In some embodiments, where the level of MEF2A expression is detected, for example, by immunoblotting, the detection agent comprises an antibody specific for MEF2A protein.

[0048] The term "antibody" includes polyclonal antibodies and monoclonal antibodies and antibody fragments, and the term "antibody fragments" includes antigen compound binding fragments of these antibodies, including Fab, F(ab')2, Fd, Fv, scFv, diabodies and minimal recognition units of antibodies, as well as single chain derivatives of these antibodies and fragments, such as scFv-Fc, etc. The type of antibody can be selected from IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE, IgD. In addition, the term "antibody" includes naturally occurring antibodies and non-naturally occurring antibodies, including, for example, chimeric, bifunctional, humanized antibodies and human antibodies, as well as related synthetic isoforms.

[0049] In some embodiments, the above-mentioned products include kits, chips, test papers, etc.

[0050] Optionally, the above-mentioned kit further comprises a reference standard for indicating the reference expression level of MEF2A, which can be a sample of colorectal cancer cells known to be resistant to oxaliplatin or a sample of colorectal cancer cells known to be sensitive to oxaliplatin.

[0051] Optionally, the kit further comprises at least one of an RNA extraction reagent, a PCR reaction buffer, dNTPs, and a DNA polymerase.

[0052] The present application also provides a method for predicting the sensitivity of a colorectal cancer patient to oxaliplatin treatment or predicting the survival rate of a colorectal cancer patient, comprising the steps of: detecting the expression level of MEF2A in a biological sample of the subject, and predicting the sensitivity of the colorectal cancer patient to oxaliplatin treatment or predicting the survival rate of the colorectal cancer patient according to the expression level of MEF2A. The expression level of MEF2A is negatively correlated with the sensitivity of the colorectal cancer patient to oxaliplatin treatment or the survival rate of the colorectal cancer patient.

[0053] The present application also provides the use of an expression inhibitor targeting MEF2A in the preparation of a product for improving the sensitivity of a colorectal cancer patient to oxaliplatin treatment or inhibiting the proliferation of oxaliplatin-resistant colorectal cancer cells.

[0054] In some embodiments, the above-mentioned expression inhibitor is an siRNA, shRNA or metformin targeting MEF2A. It can be understood that the expression inhibitor is not limited to this, and other agents known to those skilled in the art that can target and inhibit the expression of MEF2A can also be used.

[0055] Metformin is a first-line drug for treating type II diabetes in clinical, and is a biguanide hypoglycemic drug. Guanidine is a strong basic polar group, and two methyl groups are non-polar hydrogen carbon side chains. The side chain determines the lipophilicity of the biguanide molecule, so that the drug binds to hydrophobic molecules such as phospholipids on the cell membrane. Therefore, metformin has a certain affinity for mitochondrial membranes, which can interfere with mitochondrial oxidative phosphorylation and energy production. Therefore, when the dosage of metformin is high, it can cause cell lactic acidosis, which may lead to cell death. The specific mechanism of metformin is not clear. Its main effect is to enhance the effect of insulin, increase the utilization of glucose in peripheral tissues, inhibit hepatic gluconeogenesis, reduce glucose release from the liver, and lower blood glucose. Its main action mode is to increase the number of low-affinity and high-binding insulin receptors, thereby increasing the binding amount of insulin and its insulin receptors on the membranes of liver cells and muscle cells, increasing the activity of receptor tyrosine kinase, increasing glucose uptake, and enhancing glucose oxidation process and non-oxidative glycogen synthesis.

[0056] The applicant found that metformin can inhibit the proliferation of MEF2A highly expressed colorectal cancer cells through drug library screening, and proved through in vitro experiments and animal experiments that MEF2A expression inhibitors such as metformin can improve the sensitivity of colorectal cancer patients to oxaliplatin treatment and inhibit the proliferation of oxaliplatin-resistant colorectal cancer cells, and therefore can be used in combination with oxaliplatin to become a new treatment for oxaliplatin-resistant colorectal cancer patients.

[0057] The application also provides a preparation method of an oxaliplatin-resistant colorectal cancer cell line, which comprises the following steps: overexpressing MEF2A gene in colorectal cancer cells. It can be understood that the specific method of overexpressing MEF2A gene in colorectal cancer cells can use expression vectors or gene editing and other methods commonly used in the art.

[0058] The oxaliplatin-resistant colorectal cancer cell line can be prepared by the above method, so as to be used for screening potential new drugs for treating oxaliplatin-resistant colorectal cancer patients.

[0059] The application will be further described in detail below mainly in combination with specific embodiments and drawings.

[0060] I. Differences in MEF2A expression of oxaliplatin parent strain and drug-resistant strain

[0061] Collect fresh tissues of colorectal cancer primary lesions and colorectal cancer recurrence lesions after oxaliplatin chemotherapy, weigh 50 mg of equal mass of tissue samples, and place them in 2 ml EP tubes. Add 1 ml of Trizol and 4 grinding beads to each EP tube, and place the EP tubes containing the tissue samples in a tissue grinder for oscillation grinding at a speed of 4.0 M / S for 30 s. Then add 200 μl of chloroform to each EP tube for extraction, mix vigorously, and stand at room temperature for 10 min. After standing, place the EP tubes in a low-temperature centrifuge and centrifuge at 12000 rpm for 15 min. After centrifugation, carefully remove the EP tubes, and observe that the liquid in the EP tube has stratified. The upper layer is the water phase layer in which RNA is dissolved, the lower layer is the organic solvent layer, and the middle white film is mainly protein components. Take a new EP tube without enzymes, carefully pipette the water phase layer liquid into the new EP tube (pipette 400 μl, and try to avoid touching the protein layer with the tip), add 500 μl of isopropanol to the new EP tube containing the water phase layer liquid for RNA precipitation, mix gently by inverting the EP tube, stand at room temperature for 5 min, centrifuge at 4°C and 12000 rpm for 10 min, and observe the white precipitate, i.e., RNA, at the bottom of the EP tube (if no white precipitate is observed, continue centrifugation for 5 min). Discard the supernatant, add 1 ml of freshly prepared 75% alcohol (75% anhydrous ethanol + 25% enzyme-free water) to the EP tube, vortex to mix, centrifuge at 4°C and 7500 rpm for 5 min, carefully pipette the supernatant (75% ethanol), and dry at room temperature for 10 min to obtain the sample to be tested. Subsequently, the sample is subjected to 2nd generation sequencing on an illumina sequencing platform, and the sequencing results are subjected to bioinformatics analysis. Using the "edgeR package" in R language, the results are analyzed according to the standards of adjust P < 0.01 and |logFC| ≥ 2, and the results are shown in Figure 1 We found that MEF2A was more highly expressed in colorectal cancer recurrence lesions after oxaliplatin chemotherapy.

[0062] We subsequently cultured HCT116 (oxaliplatin parent strain) and HCT116 / L (oxaliplatin-resistant strain), collected the cells when the cell confluence reached about 90%, added RIPA lysis buffer (RIPA: PMSF: PIC = 100: 1: 2) for cell lysis, subjected the cells to ultrasonic crushing after lysis for 30 min, then centrifuged at 12000 rpm for 30 min, took the supernatant, measured the protein concentration by BCA method, then added loading buffer for protein boiling to fully denature, prepared SDS polyacrylamide gel for electrophoresis, and detected the expression of MEF2A in HCT116 and HCT116 / L cells. The results are shown in Figure 2 We found that the expression of MEF2A in the oxaliplatin-resistant strain was significantly higher than that in the parent strain.

[0063] Transcriptome data of colorectal cancer and healthy controls were downloaded from TCGA database, and analyzed by using the "edgeR package" in R language. The criteria for adjustment P<0.01, |logFC|≥2 were used for analysis, and the "survival package" was used for prognosis analysis. It was found that the expression of MEF2A was related to lymph node metastasis of colorectal cancer (as shown in Figure 3 The ROC curve showed that MEF2A could be used as an indicator for predicting the survival rate of patients with colorectal cancer (as shown in Figure 4 .

[0064] II. Screening of drugs targeting MEF2A

[0065] We first used the FDA-approved drug library (Selleck Chemals) to screen CCK8 by constructing MEF2A stable overexpression colorectal cancer cell lines using expression vectors. This library contains more than 480 FDA-approved drugs for indications, including tumors, cardiovascular diseases, viral and bacterial infectious diseases, and neuropsychiatric diseases.

[0066] 5000 cells were cultured per well, and the cells were treated at a concentration of 10 μM in the first round, and the concentration of metformin was set at 10 mM according to the cancer-related cell research concentration. The second round of screening used 50% cell survival rate as the threshold, and 1 μM concentration was used as the threshold with 50% survival rate, and the concentration of metformin was 1 mM, and the action time was 72 h, and each group had 3 repeated wells. The first round of screening was performed on the MEF2A overexpression stable line, and 19 drugs were obtained, as shown in Figure 5 , which were afatinib, dasatinib, belinostat, doxorubicin, epirubicin hydrochloride, fludarabine, vincristine, entecavir, omeprazole, pirarubicin, tenofovir, fludarabine, disulfiram, teniposide, albendazole, crystal violet, metformin, bortezomib, and tigecycline. The second round of screening was performed on these 19 drugs, and it was found that metformin could well inhibit the proliferation of MEF2A overexpression colorectal cancer cell lines (as shown in Figure 6 .

[0067] We subsequently found through CCK8 experiments that overexpression of MEF2A could promote the proliferation of colorectal cancer cells, and the addition of metformin could inhibit the proliferation of MEF2A overexpression cell lines (as shown in Figure 7 ), and further plate cloning experiments confirmed that overexpression of MEF2A could promote the proliferation of colorectal cancer cells, and the addition of metformin could inhibit the proliferation of MEF2A overexpression cell lines (as shown in Figure 8 .

[0068] In addition, after adding different concentrations of metformin to treat HCT8, SW480, and HCT116 cell lines, respectively, it was found thatFigure 9 As shown, the expression level of MEF2A was also significantly reduced by electrophoretic detection. The above experiments proved that metformin inhibited the progression of colorectal cancer by inhibiting the expression of MEF2A.

[0069] III. Drugs targeting MEF2A can improve the sensitivity of colorectal cancer cells to oxaliplatin

[0070] We used plate cloning experiments, with 5000 cells per well, evenly spread in 12-well plates, and added drugs after one week of culture, and the results are shown in Figure 10 As shown, it was found that oxaliplatin could significantly inhibit the colony formation of the parent strain, but oxaliplatin did not affect the colony formation of the drug-resistant strain. At the same time, we found that the combination of oxaliplatin and metformin had a stronger inhibitory effect on the colony formation of the drug-resistant strain than metformin alone, that is, metformin not only inhibited the proliferation of the drug-resistant strain, but also improved the sensitivity of the drug-resistant strain to oxaliplatin.

[0071] In addition, after knocking down the expression of MEF2A in the drug-resistant strain by siRNA, plate cloning experiments were performed, and it was also found that the sensitivity of the drug-resistant strain to oxaliplatin was significantly improved, and oxaliplatin could effectively inhibit the colony formation.

[0072] Further, mouse animal model experiments also proved that the combination of metformin and oxaliplatin could effectively inhibit tumor growth and restore the sensitivity of oxaliplatin-resistant CRC tumors to oxaliplatin.

[0073] In summary, the present application proves through a series of experiments that MEF2A can be used as a new detection marker for the sensitivity of colorectal cancer patients to oxaliplatin treatment or the prediction of the survival rate of colorectal cancer patients, and that metformin and other MEF2A expression inhibitors can effectively improve the sensitivity of oxaliplatin-resistant cells to oxaliplatin, making oxaliplatin have a stronger killing ability on drug-resistant colorectal cancer cells. Therefore, metformin and other MEF2A expression inhibitors combined with oxaliplatin can become a new treatment for colorectal cancer patients resistant to oxaliplatin.

[0074] The above is a preferred embodiment of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. Application of MEF2A expression level detection reagent in the preparation of products for predicting the sensitivity of colorectal cancer patients to oxaliplatin treatment.

2. The application according to claim 1, characterized in that, The detection reagent is used for detection at the nucleic acid level.

3. The application according to claim 2, characterized in that, The detection reagent is used to perform any of the following methods: Polymerase chain reaction, denaturing gradient gel electrophoresis, nucleic acid sequencing, microarray analysis, denaturing high-performance liquid chromatography, in situ hybridization, and biomass spectrometry.

4. The application according to claim 2, characterized in that, The detection reagent includes PCR primers.

5. The application according to claim 1, characterized in that, The detection reagent is used for protein detection.

6. The application according to claim 5, characterized in that, The detection reagent is used to perform any of the following methods: Mass spectrometry, amino acid sequencing, electrophoresis, Western blotting, immunoprecipitation, and immunohistochemistry.

7. The application according to claim 5, characterized in that, The detection reagent includes a MEF2A protein-specific antibody.

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