Autophagy-related Gene 7 (ATG7) and Reactive Oxygen Species/Extracellular Signal-regulated Kinase Regulate Tetrandrine-induced Autophagy in Human Hepatocellular Carcinoma
Autophagy-related Gene 7 (ATG7) and Reactive Oxygen Species/Extracellular Signal-regulated Kinase Regulate Tetrandrine-induced Autophagy in Human Hepatocellular Carcinoma
复制标题
自噬相关基因 7 (ATG7) 和活性氧/细胞外信号调节激酶调节粉防己碱诱导的人肝细胞癌自噬
DOI：
10.1074/jbc.m112.370585
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发表时间：
2012-10-12
影响因子：
4.8
通讯作者：
Li, Wenhua
中科院分区：
文献类型：
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作者：
Gong, Ke;Chen, Chao;Li, Wenhua
汉防己甲素是从中药粉防己中分离得到的一种双苄基异喹啉类生物碱，具有较强的抗肿瘤作用，有望成为一种新型的肿瘤化疗药物。我们以前报道过高浓度粉防己碱诱导肝癌细胞凋亡。在这里，我们发现，在人肝细胞癌（HCC）细胞中，低剂量的粉防己碱（5 μ M）诱导LC 3-II的表达，导致酸性自噬溶酶体空泡（AVO）的形成，并导致与GFP-LC 3蛋白，这都是细胞自噬的标记物点状荧光图案。汉防己甲素诱导细胞内活性氧（ROS）的产生，并与ROS清除剂治疗显着废除汉防己甲素诱导的自噬。这些结果表明，ROS的产生在促进粉防己碱诱导的自噬中起着重要作用。粉防己碱诱导的线粒体功能障碍导致ROS积累和自噬。ROS的产生激活了ERK MAP激酶，ERK信号通路至少部分促进了汉防己甲素诱导的肝癌细胞自噬。此外，我们还发现汉防己甲素通过转录调控自噬相关基因7（ATG 7）的表达，从而促进了汉防己甲素诱导的自噬。除了体外研究外，在体内也观察到类似的结果，其中粉防己碱在肿瘤异种移植模型中引起ROS的积累并诱导细胞自噬。有趣的是，粉防己碱处理也诱导自噬在一个ROS依赖的方式在C。elegans肌肉细胞因此，这些发现表明粉防己碱是一种有效的自噬激动剂，可能是一个有前途的临床化疗药物。
Tetrandrine, a bisbenzylisoquinoline alkaloid isolated from the broadly used Chinese medicinal herb Stephaniae tetrandrae, exhibits potent antitumor effects and has the potential to be used as a cancer chemotherapeutic agent. We previously reported that high concentrations of tetrandrine induce apoptosis in liver cancer cells. Here, we found that in human hepatocellular carcinoma (HCC) cells, a low dose of tetrandrine (5 mu M) induced the expression of LC3-II, resulted in the formation of acidic autophagolysosome vacuoles (AVOs), and caused a punctate fluorescence pattern with the GFP-LC3 protein, which all are markers for cellular autophagy. Tetrandrine induced the production of intracellular reactive oxygen species (ROS), and treatment with ROS scavengers significantly abrogated the tetrandrine-induced autophagy. These results suggest that the generation of ROS plays an important role in promoting tetrandrine-induced autophagy. Tetrandrine-induced mitochondrial dysfunction resulted in ROS accumulation and autophagy. ROS generation activated the ERK MAP kinase, and the ERK signaling pathway at least partially contributed to tetrandrine-induced autophagy in HCC cells. Moreover, we found that tetrandrine transcriptionally regulated the expression of autophagy related gene 7 (ATG7), which promoted tetrandrine-induced autophagy. In addition to in vitro studies, similar results were also observed in vivo, where tetrandrine caused the accumulation of ROS and induced cell autophagy in a tumor xenograft model. Interestingly, tetrandrine treatment also induced autophagy in a ROS-dependent manner in C. elegans muscle cells. Therefore, these findings suggest that tetrandrine is a potent autophagy agonist and may be a promising clinical chemotherapeutic agent.