褐藻素诱导肝癌HepG2细胞凋亡和自噬的机制

Fucoxanthin Induced Hepatoma HepG2 Cells Apoptosis,Autophagy and It's Mechanism

目的:探讨褐藻素诱导肝癌HepG2细胞凋亡和自噬的分子机制。方法:MTT法检测细胞增殖,流式细胞仪检测细胞凋亡,高内涵活细胞成像系统检测细胞自噬,Western blotting检测蛋白的表达。结果:褐藻素剂量依赖性地抑制肝癌HepG2细胞的增殖,诱导Beclin 1表达显著增强、促进LC3 I转化为LC3 II以及自噬溶酶体的形成;褐藻素剂量依赖性地增加Annexin V染色阳性细胞数量、诱导Caspase-3活化、线粒体膜电位下降并伴随Cytochrome c从线粒体释放到细胞浆中、上调Bax和PTEN的表达及下调Bcl-2的表达,抑制Akt、p70S6K及mTOR的磷酸化;自噬抑制剂3-MA可增加褐藻素诱导的细胞凋亡率,并促进Caspase-3的活化。结论:褐藻素通过抑制Akt信号通路诱导肝癌HepG2细胞凋亡和自噬,且该自噬抑制细胞凋亡。

Objective：To evaluate the antiproliferative effects of fucoxanthin,a major carotenoid found in edible seaweed,and also to elucidate the molecular mechanism on hepatoma HepG2 cells.Method：Th eantiproliferative effects of fucoxanthin was evaluated using MTT assay.Fucoxanthin-mediated cell apoptosis was evaluated using Flow Cytometer.Autophagy detection with acridine orange staining and Lyso-Tracker Red staining by High Content Screening （HCS）.The protein expression was detected using Western blotting.Result：Fucoxanthin exerts potent antiproliferative activity on HepG2 cells in a dose-dependent manner.Furthermore,fucoxanthin induces HepG2 cells autophagy and apoptosis.After treatment with fucoxanthin,the protein expression of LC3 Ⅱ and Beclin 1 were enhanced.Furthermore,fucoxanthin induced cell apoptosis,Caspase-3 activation,mitochondrial membrane potential decrease,cytochrome C release from mitochondria to cytoplasm,upregulation the protein expression of Bax and PTEN,downregulation the protein expression of Bcl-2,and also inhibited the phosphorylation of Akt,p70S6K and mTOR.Whereas 3-methyladenine （3-MA）,a phosphatidylinositol 3-phosphate kinase inhibitor,enhanced the fucoxanthin-mediated apoptosis and caspase-3 activation.Conclusion：Fucoxanthin-mediated autophagy and apoptosis were due to inhibition of Akt signal pathway in HepG2 cells.