Smac过表达增强氯化镉对人肝癌细胞SMMC-7721的增殖抑制和促凋亡作用

目的:研究Smac过表达联合氯化镉(CdCl2)对人肝癌细胞SMMC-7721增殖和凋亡的影响,为以Smac为基础的肿瘤基因治疗以及镉作为抗肝癌药物的开发提供实验依据.方法:实验共设立5组,分别为对照组、pcDNA3.1+组、pcDNA3.1+-hSmac组、CdCl2组以及CdCl2联合Smac组.对照组细胞不进行细...

Enhancement of antiproliferative and proapoptotic effects of cadmium chloride when coupling with Smac over-expression in hepatocellular carcinoma cells

Objective To study the effects of the cotreatment of cadmium chloride(CdCl2) and Smac over-expression on proliferation and apoptosis of hepatocellular carcinoma cells,SMMC-7721,and provide an experimental basis for the Smac-based tumor gene therapy and the development of cadmium as the antihepatoma drug.Methods SMMC-7721 were divided into five groups,which were control,pcDNA3.1+,pcDNA3.1+-hSmac,single CdCl2-treated and CdCl2 plus Smac groups respectively.The cells in control group had no transfection or CdCl2 treatment,while those in pcDNA3.1+ and pcDNA3.1+-hSmac groups were transfected with null vector pcDNA3.1+ or pcDNA3.1+-hSmac respectively through lipofectamine-mediated method,and those in CdCl2-treated groups were exposed to CdCl2 at the concentration of 10,20 and 30 μmol·L-1 respectively,and those in CdCl2 plus Smac groups were transfected with pcDNA3.1+-hSmac firstly,and then treated with CdCl2 after transfection for 24 h.MTT assay was used to determine the effect of Smac over-expression and CdCl2 on proliferation,and both AO/EB fluorescence staining and FCM with Annexin Ⅴ and PI double-staining methods for apoptosis.Results The MTT results showed that compared with control group,except for the null-vector pcDNA3.1+ group,the inhibitory rates in the rest groups were increased significantly(P<0.01 or P<0.001).In single CdCl2-treated groups,the inhibitory rate was increased with the increasing of treatment doses,whereas,each Smac coupled group presented significantly higher inhibitory rate than the corresponding single CdCl2-treated group(P<0.001).AO/EB staining manifested that the cells in control group were in good condition,while those in pcDNA3.1+-hSmac,30 μmol·L-1 CdCl2 treatment,and CdCl2 plus Smac groups appeared the morphological changes of apoptosis,especially in the last group.Furthermore,the results acquired by FCM showed that the apoptotic rate in pcDNA3.1+-hSmac group was increased significantly when compared with control and pcDNA3.1+ groups respectively(P<0.001).However,the apoptotic rate in CdCl2 pluse Smac group was the highest,which was significantly higher than that in single 30 μmol·L-1 CdCl2-treated group(P<0.001).Conclusion CdCl2 has cytotoxicity to SMMC-7721 cells.It could inhibit cellular proliferation in a dose-dependent manner,and induce apoptosis.Smac over-expression could inhibit cellular proliferation and slightly induce apoptosis independently.