Influence of silencing Smad4 gene in proliferation and apoptosis of breast carcinoma MCF-7 cells / 吉林大学学报(医学版)

ABSTRACT

Objective:To study the effects of down-regulated Smad4 expression on the proliferation and apoptosis of breast carcinoma MCF-7 cells,and to explore their mechanisms.Methods:The human breast carcinoma MCF-7 cells and MDA-MB-231 cells were cultured in vitro.RT-PCR method was used to detect the expression levels of Smad4 mRNA in MCF-7 cells and MDA-MB-231 cells.The Smad4-shRNA plasmid and Scramble-shRNA plasmid were respectively stably transfected into the MCF-7 cells with high expression of Smad4.The experiment was divided into non-transfected MCF-7 cells (normal control) group,Smad4 gene silencing group,Scramble(negative control) group.The proliferation abilities of the cells in various groups were detected by CCK-8 method.The apoptotic rates of the cells in various groups were detected by flow cytometry.Real-time PCR method wasused to detect the mRNA expression levels of the proliferation-related genes CDKN1A,CDK1 and CDK2 and the apoptosisrelated genes Suvivin,bcl-2,caspase 3 and caspase 9.Results:The proliferation abilities of cells had no statistical significance between various groups (P＞0.05).The mRNA expression levels of CDKN1A,CDK1 and CDK2 in the cells had no statistical significance between various groups (P＞0.05).Compared with normal control group and negative control group,the apoptotic rate of the cells in Smad4 gene silencing group was significantly decreased (P＜0.01),the expression levels of Suvivin and bcl-2 mRNA in Smad4 gene silencing group were significantly increased (P＜0.01),and the mRNA expression levels of caspase 3 and caspase 9 in Smad4 gene silencing group were significantly decreased (P＜0.05).Conclusion:Smad4 could induce the apoptosis of MCF-7 cells by downregulating the expressions of Suvivin and bcl-2 and up-regulating the expressions of caspase 3 and caspase 9.