δ-生育三烯酚诱导人肝癌HepG2细胞凋亡的机制研究

Study on the action mechanism for δ-tocotrienol-induced apoptosis of human hepatoma HepG2 cells

目的:探讨δ-生育三烯酚诱导人肝癌HepG2细胞凋亡的作用机制。方法:应用MTT法检测δ-生育三烯酚对人肝癌HepG2细胞增殖的影响,应用高内涵活细胞成像系统检测δ-生育三烯酚对人肝癌HepG2细胞凋亡率、细胞周期以及线粒体膜电位的影响,Western印迹法检测δ-生育三烯酚对人肝癌HepG2细胞凋亡相关蛋白(如caspase-3、caspase-8、caspase-9、Bcl-2、Bax、tBid和cytochrome C)表达的影响。结果:δ-生育三烯酚呈浓度依赖性地抑制肝癌HepG2细胞生长并诱导其凋亡,其机制为δ-生育三烯酚降低线粒体膜电位,并诱导cytochrome C从线粒体释放到细胞质中,调控Bcl-2家族蛋白表达(如上调Bax及tBid蛋白的表达,下调Bcl-2蛋白的表达),继而引起caspase-3、caspase-8和caspase-9的活化,最终导致肝癌HepG2细胞凋亡。结论:δ-生育三烯酚可能通过线粒体途径及膜死亡受体途径共同诱导人肝癌细胞HepG2凋亡。

Objective：To elucidate action mechanism of δ-tocotrienol in inducing apoptosis of human hepatoma HepG2 cells.Methods：Cell proliferation and viability were assessed by MTT assay;cell cycle distribution,apoptotic rate and mitochondrial membrane potential were measured by using high content screening system;the expression of apoptosis-related protein such as caspase-3,caspase-8,caspase-9,Bcl-2,Bax,tBid and cytochrome C in the HepG2 cells were evaluated by Western blotting.Results：δ-Toco-trienol inhibited HepG2 cell proliferation and induced apoptosis in a dose-dependent manner.This growth-inhibiting effect of δ-toco-trienol correlated with loss of mitochondrial membrane potential and release of cytochrome C from mitochondria to cytoplasm,and regulation of the protein expression of Bcl-2 family members,such as up-regulation of Bax and tBid and down-regulation of Bcl-2.Subsequently tocotrienol induced the activation of caspase-3,caspase-8,and caspase-9 which finally induced apoptosis of hepatoma HepG2 cells.Conclusion：δ-Tocotrienol induced apoptosis of human hepatoma HepG2 cells via mitochondrial pathway and membrane death receptor pathway.