Research Institute of Biomedical Engineering and Department of Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
Department of Biological Science, Sungkyunkwan University, Suwon, Kyunggi, Korea.
J Cell Mol Med. 2018 Dec;22(12):6345-6356. doi: 10.1111/jcmm.13933. Epub 2018 Oct 19.
4-O-methylascochlorin (MAC) is a derivative of ascochlorin, a prenyl-phenol compound antibiotic isolated from the fungus Ascochyta viciae. MAC induces caspase/poly (ADP-ribose) polymerase-mediated apoptosis in leukemia cells. However, the effects of MAC on autophagy in cancer cells and the underlying molecular mechanisms remain unknown. Here, we show that MAC induces autophagy in lung cancer cells. MAC significantly induced the expression of autophagy marker proteins including LC3-II, Beclin1, and ATG7. MAC promoted AMP-activated protein kinase (AMPK) phosphorylation and inhibited the phosphorylation of mammalian target of rapamycin (mTOR) and its downstream signalling proteins P70S6K and 4EBP1. The AMPK activator AICAR upregulated LC3-II expression through the AMPK/mTOR pathway similar to the effects of MAC. MAC-induced LC3-II protein expression was slightly reduced in AMPK siRNA transfected cells. MAC upregulated hypoxia-inducible factor-1α (HIF-1α) and BNIP3, which are HIF-1α-dependent autophagic proteins. Treatment with CoCl , which mimics hypoxia, induced autophagy similar to the effect of MAC. The HIF-1α inhibitor YC-1 and HIF-1α siRNA inhibited the MAC-induced upregulation of LC3-II and BNIP3. These results suggest that MAC induces autophagy via the AMPK/mTOR signalling pathway and by upregulating HIF-1α and BNIP3 protein expression in lung cancer cells.
4-O-甲基阿索克拉林（MAC）是一种从真菌阿斯科拉塔（Ascochyta viciae）中分离出来的前体酚类抗生素阿索克拉林的衍生物。MAC 诱导白血病细胞中 caspase/多聚（ADP-核糖）聚合酶介导的细胞凋亡。然而，MAC 对癌细胞自噬的影响及其潜在的分子机制尚不清楚。在这里，我们表明 MAC 诱导肺癌细胞发生自噬。MAC 显著诱导自噬标志物蛋白的表达，包括 LC3-II、Beclin1 和 ATG7。MAC 促进 AMP 激活蛋白激酶（AMPK）磷酸化并抑制哺乳动物雷帕霉素靶蛋白（mTOR）及其下游信号蛋白 P70S6K 和 4EBP1 的磷酸化。AMPK 激活剂 AICAR 通过 AMPK/mTOR 通路上调 LC3-II 的表达，与 MAC 的作用相似。在 AMPK siRNA 转染的细胞中，MAC 诱导的 LC3-II 蛋白表达略有减少。MAC 上调缺氧诱导因子-1α（HIF-1α）和 BNIP3，它们是 HIF-1α 依赖性自噬蛋白。用 CoCl2 处理可模拟缺氧，与 MAC 的作用相似，诱导自噬。HIF-1α 抑制剂 YC-1 和 HIF-1α siRNA 抑制 MAC 诱导的 LC3-II 和 BNIP3 的上调。这些结果表明，MAC 通过 AMPK/mTOR 信号通路诱导自噬，并通过上调肺癌细胞中 HIF-1α 和 BNIP3 蛋白的表达来诱导自噬。
