ABSTRACT
Objective:To investigate the effect of STIM1 on the survival and proliferation of breast cancer cells and its preliminary mechanism analysis.Methods:Normal mammary epithelial cells MCF-10A as control,the expression of STIM1 in MCF7, HCC1569,MDA-MB-231 and BT549 breast cancer cells were detected by Western blot;STIM1 siRNA sequence(STIM1-siRNA group) were transfected into MDA-MB-231 cells,and the negative control group and the blank control group were set up,the protein expression of STIM1 in each group were detected after cells were transfected for 48 h;MTT method was used to detect cell activity cells were transfected for 24 h,48 h and 72 h;cell apoptosis was detected after cells were transfected for 48 h by flow cytometry;the mRNA expression of IL-6 and TNF-α were detected by RT-PCR;the expression of PCNA,Bcl-2,Bax,Caspase3,STAT3 and p-STAT3 protein were detected by Western blot.Results:The expression of STIM1 protein in breast cancer cells was significantly higher than that in MCF-10A cells (P<0.05);the expression of STIM1 protein in MDA-MB-231 cells transfected STIM1-siRNA was significantly lower than the control group(P<0.05);compared with the control group,cell viability in STIM1-siRNA group decreased significantly in cells were transfected for 48 h and 72 h,the apoptosis rate in 48 h was significantly increased,the expression of IL-6 and TNF-α mRNA sig-nificantly decreased,the expression of PCNA,Bcl-2 and p-STAT3 protein were significantly decreased,the expression of Bax and Caspase3 protein increased significantly.Conclusion:STIM1 gene is highly expressed in breast cancer cells.Inhibition of STIM1 expression by RNA interference can down regulate the activity of cancer cells,induce apoptosis,enhance immunity and by down regulation STAT3 signal.