薯蓣皂苷对肝癌细胞Bel-7402和正常人肝细胞LO2增殖和凋亡的影响

Proliferation and apoptosis of dioscin in Bel-7402 and LO2 cells

目的研究薯蓣皂苷(dioscin)对肝癌细胞Bel-7402及正常人肝细胞LO2增殖和凋亡的影响及其可能机制。方法将0.5~16μmol/L薯蓣皂苷干预Bel-7402肝癌细胞和LO2肝细胞24 h,使用MTT法检测细胞增殖抑制作用,倒置显微镜观察细胞形态变化,Hoechst33258染色法观察细胞凋亡的形态学变化,JC-1染色法检测线粒体膜电位水平变化;Western blot蛋白质印迹法观察薯蓣皂苷对两种细胞中Bcl-2、Bax蛋白表达的影响。结果与阴性对照组比较,薯蓣皂苷各剂量组可显著抑制Bel-7402肝癌细胞和LO2肝细胞增殖,并呈剂量依赖性,其作用于Bel-7402肝癌细胞的IC50为2.04μmol/L,作用于LO2肝细胞的IC50为2.76μmol/L;与阴性对照组比较,1μmol/L、2μmol/L薯蓣皂苷组Bel-7402肝癌细胞及LO2肝细胞分布密度降低,细胞出现变圆脱落死亡,细胞边界模糊,并诱导细胞发生凋亡。JC-1染色结果显示,薯蓣皂苷作用于两种细胞后线粒体膜电位均显著降低(P<0.01)。Western blot蛋白质印迹法检测结果显示,薯蓣皂苷均可抑制两种细胞中Bcl-2蛋白的表达,上调Bax蛋白的表达(P<0.05,P<0.01)。结论薯蓣皂苷能够抑制Bel-7402肝癌细胞和LO2肝细胞的体外增殖,其机制可能是降低线粒体膜电位,抑制Bcl-2蛋白表达,上调Bax蛋白的表达,诱导细胞发生凋亡。提示薯蓣皂苷在发挥抗肝癌作用的同时亦对肝细胞具有损伤作用。

Objective To study the effects of dioscin on Bel-7402 and LO2 cell proliferation and apoptosis and its possible mechanisms.Methods Bel-7402 and LO2 cells were exposed to 0.5~16μmol/L dioscin for 24 h,and inhibition of cell proliferation was examined via MTT assay.Morphologic changes in the cells were quantified using an inverted microscope,and Hoechst 33258 staining was used to observe morphological changes in the apoptotic cells.Changes in the mitochondrial membrane potential were measured using JC-1 staining.Bcl-2 and Bax expression were detected via western blot.Results Compared with the negative control group,Bel-7402 and LO2 cell proliferation was significantly inhibited dose-dependently after exposure to all concentrations of dioscin.The IC50 of the Bel-7402 cells was 2.04μmol/L;the IC50 of the LO2 cells was 2.76μmol/L.Compared with those of the negative control group,the cells showed varying degrees of distribution,density reduction,roundness,exfoliation,death and necrosis induced by 1 and 2μmol/L of dioscin.The cell boundary was blurred and induced cell apoptosis.JC-1 staining result showed that the mitochondrial membrane potential was significantly decreased in both cell lines after treatment with dioscin(P<0.01).Western blot result showed that dioscin significantly increased Bax expression and inhibited Bcl-2 expression in both cells lines(P<0.05;P<0.01).Conclusions Dioscin inhibited Bel-7402 and LO2 cell proliferation in vitro.The possible mechanism may have been that dioscin increased Bax expression,inhibited Bcl-2 expression,and induced apoptosis;thus,dioscin may induce liver injury during development of its anti-hepatocarcinoma functions.