Biological Effects And Mechanism Of MicroRNA-182 Of Triple-negative Breast Cancer Cell

Objective: Breast cancer is the most common malignant tumor in women.Triple negative breast cancer(TNBC)accounts for about 10-20% of all breast cancer pathological types.It has high proliferation activity,increased immune infiltration,basal and mesenchymal phenotypes,and lack of homologous recombination and repair.Studies have shown that microRNA(microRNA)plays an important role in the occurrence and development of breast cancer.In this study,we observed the effects of microRNA-182 on the biological behavior of triple-negative breast cancer cells by transfecting microRNA-182 mimic and microRNA-182 inhibitor,and detected the expression of BRCA1,BRCA2,P53 and P21 in triple-negative breast cancer cells,and it provided a new theoretical basis for further exploring the mechanism of action of miRNA-182 in BRCA1-related pathways and help to develope targeted drugs for triple-negative breast cancer.Methods: 1.MicroRNA-182 was transfected into MDA-MB-231 cell line by liposome,and the miRNA-182 mimic group,miRNA-182 inhibitor group and negative control group were established.2.MDA-MB-231 cell lines with stable and high expression of BRCA1 were established by lentivirus transfection of BRCA1 into MDA-MB-231 cell lines,and then microRNA-182 was transfected with liposome to establish BRCA1+microRNA-182 mimic,BRCA1+microRNA-182 inhibitor and negative control group(BRCA1 group).3.The expression levels of BRCA1,BRCA2,p53 and p21 were detected by Wstern blot.4.Observation of cell proliferation ability: MTT test was used to detect the difference of cell proliferation ability in each group after transfection.Results: 1.Western blot results showed that the expression levels of BRCA1,BRCA2,p53 and p21 in the microRNA182 mimic group were significantly lower than those in the negative control group(p < 0.05);the expression levels of BRCA1,BRCA2,p53 and p21 in the microRNA182 inhibitor group were significantly higher than those in the negative control group(p < 0.05).Compared with BRCA1 group,the expression levels of BRCA1,BRCA2,p53 and p21 protein in BRCA1 + microRNA-182 mic group decreased significantly(p < 0.05);compared with BRCA1 group,the expression levels of BRCA1,BRCA2,p53 and p21 protein in BRCA1 + microRNA-182 inhibitor group increased significantly(p < 0.05).2.MTT assay showed that compared with negative control group,there was no significant change in the cell proliferation rate in the microRNA-182 mimic group(p >0.05);compared with the negative control group,the cell proliferation rate in themicroRNA-182 inhibitor group was significantly lower(p < 0.05).Compared with BRCA1 group,the cell proliferation rate of BRCA1 + microRNA182 mimic group did not increase significantly(p > 0.05);compared with BRCA1 group,the cell proliferation rate of BRCA1 +microRNA182 inhibitor group did not decrease significantly.(p > 0.05).Conclusions: MicroRNA182 can inhibit the expression of BRCA1 and its pathway protein,but its function of promoting TNBC cell proliferation is uncertain,which may be related to the inhibition of proliferation by other target genes regulated by microRNA182 at the same time.