Downregulation of BRG1 inhibits the growth of human breast cancer cells

Objective To investigate the role of BRG1 gene on human breast cancer cell proliferation.Methods The BRG1 small interfering RNA (siRNA) were transferred into MDA-MB-231 and BT-549 breast cancer cells.The expression of BRG1 gene in both cancer cells were assessed by Western blotting.The proliferation of both cancer cells after BRG1 interference were measured by cell counting kit8 (CCK-8) assay.The cell cycle of breast cancer cells were detected by flow cytometry.The expression levels of cyclin family (Cyclin E,Cyclin E2,Cyclin B1) and CDK inhibitor proteins (p27) were detected by Western blotting.Results BRG1 siRNA could silence the expression of BRG1 gene in both breast cancer cells significantly.BRG1 interference could drastically decreased the ability of cell proliferation in both breast cancer cells and rose to its peak level at 96 h.The G1 population in both breast cancer cells treated by BRG1 siRNA [(17.08 ± 3.22) ％,(11.49 ± 3.43) ％] increased significantly than the cells treated by control siRNA [(6.38 ±2.14)％,(2.86 ± 1.87)％] at 9 h.The cxpression levels of Cyclin E,Cyclin E2,Cyclin B1 proteins were drastically decreased in both breast cancer cells after BRG1 interference,at the same time,p27 protein expression levels was significantly increased.Conclusion Silence of BRG1 could suppress human breast cancer cell growth through down-regulation of Cyclin E,Cyclin E2,Cyclin B1 proteins,up-regulation of p27 proteins making cell cycle arrest at G1 phase. Key words: BRG1 gene; Breast cancer; Proliferation; Cell cycle