Expression Of MicroRNA And PD-L1 In Different Human Breast Cancer Cells

BackgroundBreast cancer is one of the most common malignancies in women.At present,breast cancer has become the first place of the incidence of malignant tumors in Chi-na.MicroRNA is a short endogenous noncoding single-stranded RNA molecule,mainly involved in post-transcriptional regulation of gene expression.MicroR-NA plays a very important role in many biological processes and pathologies,and often appears the abnormal expression in tumor cells.Programmed death-ligand 1(PD-L1,B7-H1,CD274)appears to be induced by inflammatory cytokines in different tumors,as an inhibitory immune-receptor of immune checkpoint mole-cules And its overexpression is also considered to be the most important mechanism for tumor cells to escape from the host immune response.Foreign research have shown that PD-L1 almost had no expression in the normal breast tissue,and it’s mainly expressed in breast cancer.However,the study of the relationship between PD-L1 expression in breast cancer tissue and the clinical prognosis of patients has achieved inconsistent results,which may be induced by the use of different immunohistochemical methods(IHC)or the purchase of antibodies from the different brands.Because most of the literatures from the country and the abroad reported the use of IHC method to research the PD-L1 expression in breast cancer tissue,but detection of PD-L1 expression in human breast cancer cells is rarely rep-orted.Also the expression of microRNA-3609 and PD-L1 in human breast cancer cells has not been reported in the literature.This study focused on the expression of microRNA-3609 and PD-L1 in different human breast cancer cells,and the relation-ship between them.ObjectiveDetected the expression of microRNA-3609 and PD-L1 in different human breast cancer cells,and the relationship between microRNA-3609 and PD-L1 expression was analyzed.Prepare for the research on the effects of microRNA-3609 on the growth of human breast cancer cells by down-regulating PD-L1 expression and its mechanism.Methods1.Using Western Blot and fluorescence quantitative PCR,we detected the protein and the mRNA expression of PD-L1 in normal human breast epithelium cell line HBL-100 and the other four human breast cancer cell lines MCF-7,MCF-7/ADR,MDA-MB-231,MDA-MB-468.2.Using the fluorescence quantitative PCR technology,we detected the mRNA expression of microRNA-3609 in the above five cells.Results1.Compared with the normal human breast epithelium cell HBL-100,PD-L1 was significantly high expressed in MDA-MB-231,MDA-MB-468 and MCF-7/ADR(P<0.05),and was highest expressed in MDA-MB-231(P<0.001).2.Compared with HBL-100,microRNA-3609 showed low expression in MDA-MB-231,MDA-MB-468 and MCF-7/ADR(P<0.05),and expressed in MCF-7/ADR lowest(P<0.001).Conclusion1.Compared with the normal human breast cells HBL-100,PD-L1 was mainly expressed in breast cancer cells.2.The expression of PD-L1 and microRNA-3609 in human breast cancer cells showed a relative negative correlation.