Fangchinoline induces autophagic cell death via p53/sestrin2/AMPK signalling in human hepatocellular carcinoma cells
Fangchinoline induces autophagic cell death via p53/sestrin2/AMPK signalling in human hepatocellular carcinoma cells
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DOI：
10.1111/j.1476-5381.2011.01349.x
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发表时间：
2011-09-01
影响因子：
7.3
通讯作者：
Feng, Yibin
中科院分区：
文献类型：
--
作者：
Wang, Ning;Pan, Weidong;Feng, Yibin
背景与目的防己内酯是一种新型的抗肿瘤药物，其细胞和分子作用机制知之甚少。本文研究了防己碱诱导人肝癌细胞株HepG2和PLC/PRF/5细胞死亡的方式及其可能的机制。应用免疫印迹、实时定量聚合酶链式反应和siRNA技术研究了自噬激活的信号转导途径。KEY RESULTSFANG CHINONLE不能诱导HepG2和PLC/PRF/5细胞的凋亡，但可剂量依赖地触发自噬，这可能是其抗肿瘤作用的机制之一。P53的核转位参与了防己内酯诱导的自噬，随后选择性地反式激活了自噬相关基因sestrin2并启动了自噬过程。AMP激活的蛋白激酶的信号也参与了sestrin2的下游靶标，并在两种细胞系中诱导了mTOR非依赖性的自噬细胞死亡。ATG5的siRNA或P53的药理阻断阻断了防己甲素诱导的自噬，抑制自噬使细胞死亡转为凋亡，提示一旦防己甲素诱导自噬，细胞死亡是不可逆转的。结论和应用防己甲素是一种高度特异的诱导肝癌细胞自噬死亡的药物，其机制新，阐明了防己甲素增强癌细胞程序性死亡的可能性。
BACKGROUND AND PURPOSEFangchinoline is a novel anti-tumour agent with little known of its cellular and molecular mechanisms of action. Here we have investigated the mode of cell death induced by fangchinoline and its underlying mechanism in two human hepatocellular carcinoma cell lines, HepG2 and PLC/PRF/5.EXPERIMENTAL APPROACHApoptosis and autophagy were monitored in fangchinoline-treated HepG2 and PLC/PRF/5 cells by histological methods. The signal transduction pathways involved in activation of autophagy were examined, using immunoblotting, real-time PCR and siRNA techniques.KEY RESULTSFangchinoline did not induce apoptosis in HepG2 and PLC/PRF/5 cells but triggered, dose-dependently, autophagy, an alternative mode of cell death which may contribute to fangchinoline's anti-tumour action. Nuclear translocation of p53 was involved in induction of autophagy by fangchinoline, followed by selective transactivation of the autophagy-related gene sestrin2 and initiation of the autophagic process. Signalling by the AMP-activated protein kinase was also involved as a downstream target of sestrin2 and induced mTOR-independent autophagic cell death in both cell lines. siRNA for Atg5 or pharmacological block of p53 abolished fangchinoline-induced autophagy and inhibition of autophagy switched cell death to apoptosis in these cells, suggesting that cell death is irreversible once autophagy is induced by fangchinoline.CONCLUSIONS AND IMPLICATIONSFangchinoline is a highly specific agent inducing autophagic cell death in hepatocellular carcinoma cells with a novel mechanism, which elucidates the potential of fangchinoline to potentiate programmed cell death in cancer cells.