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

ABSTRACT

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.