自噬
细胞凋亡
缺氧(环境)
芬瑞替尼
程序性细胞死亡
细胞生物学
赫拉
生物
活力测定
癌细胞
癌症研究
细胞
化学
细胞培养
生物化学
癌症
氧气
维甲酸
维甲酸
有机化学
遗传学
作者
Xiao Wen Liu,Yi Su,Hong Zhu,Ji Cao,Wan Jing Ding,Yu Zhao,Qiao He,Bo Yang
标识
DOI:10.1016/j.phrs.2010.07.002
摘要
Novel therapeutic strategies are needed to address and to solve the emerging problem of hypoxia-induced resistance to anticancer drugs. N-(4-Hydroxyphenyl)retinamide (4-HPR) exhibits potent anticancer and chemopreventive activities, but its inefficiency under hypoxia, through undetermined mechanisms, may contribute to its lack of activity in clinical trials. In this study, we showed that under normoxia, 4-HPR resulted in apoptosis and ultimate cell death; in contrast, under hypoxia, autophagy was preferentially induced by 4-HPR at an equivalent concentration, accompanied by microtubule associated protein light-chain 3 (LC3) conversion and acidic vesicular organelle formation. Under hypoxia, autophagy inhibition by 3-methyladenine or chloroquine significantly enhanced apoptosis and decreased cell viability in 4-HPR-exposed cells, indicating that autophagy prevents cancer cell death and presumably leads to hypoxia-induced resistance to 4-HPR. Importantly, knockdown of hypoxia-inducible factor-1α (HIF-1α) inhibited autophagy but promoted 4-HPR-induced apoptosis under hypoxia, demonstrating its critical role as a mediator of this protective autophagy. The present study provides the first evidence supporting the hypothesis that autophagy and apoptosis can be differentially induced by 4-HPR under different oxygen conditions; mediated by HIF-1α, 4-HPR-induced autophagy under hypoxia confers a survival advantage to HeLa cells, protects them from 4-HPR-induced death signals, and thus contributes to their hypoxia-induced resistance to this agent. Our data suggest that autophagy inhibition is a potential alternative strategy to overcome hypoxia-induced resistance to 4-HPR and enhance the anticancer activities of this agent.
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