Application of BRCA1 protein in preparation of drugs for reversing drug resistance of tumor cells to MTX (Methotrexate)

The invention relates to application of BRCA1 protein in preparation of drugs for reversing the drug resistance of tumor cells to MTX (Methotrexate), and belongs to the technical field of tumor biotherapy. In a constructed MTX drug resistant cellular evolution model, drug resistant cells containing DMs (double minutes) are selected as the research object, and by determination on high expression of BRCA1 protein in drug resistant cells of HT29 containing DMs, the stable existent relation among the BRCA1 protein, the pathway where the BRCA1 protein is located and the double minute containing DHFR drug resistant genes is further studied. According to the application of BRCA1 protein in preparation of drugs for reversing the drug resistance of tumor cells to MTX (methotrexate), provided by the invention, HT29MTX drug-resistant clones causing stable interference to BRCA1 are constructed by utilizing the liposome transfection method, Western Blot, FISH, Real-time PCR, MTT, immunofluorescence and other methods are utilized for respectively detecting the impacts of interference to BRCA1 on cell drug resistance, amplification degree and amplification form of DHFR genes, DNA double strand break, double strand break repair pathway, the cell cycle and micronucleus efflux, so as to determine the fact that inhibition on BRCA1 protein can promote efflux of DMs and reverse the drug resistance of tumor cells to MTX.