Extracellular signal-regulated kinase, receptor interacting protein, and reactive oxygen species regulate shikonin-induced autophagy in human hepatocellular carcinoma
Extracellular signal-regulated kinase, receptor interacting protein, and reactive oxygen species regulate shikonin-induced autophagy in human hepatocellular carcinoma
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DOI：
10.1016/j.ejphar.2014.05.034
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发表时间：
2014-09-05
影响因子：
5
通讯作者：
Li, Wenhua
中科院分区：
文献类型：
--
作者：
Gong, Ke;Zhang, Zhenxing;Li, Wenhua
紫草素是从中药紫草中提取的一种萘醌类化合物，具有潜在的肿瘤化疗药物的作用。我们以前的数据表明，高剂量（约6 μ M）的紫草素诱导人肝细胞癌（HCC）细胞凋亡。在这里，我们发现，一个低剂量的紫草素（2.5 μ M）和一个短的处理时间（12小时）诱导自噬，证明了微管相关蛋白1A/1B-轻链3（LC 3）-II的上调，酸性自噬空泡（AVO）的形成，和GFP-LC 3蛋白的点状荧光图案。接下来，我们研究了其机制，发现紫草素处理后活性氧的积累。活性氧清除剂NAC和Tiron完全阻断了自噬。我们进一步发现ERK通过产生活性氧和抑制RIP通路而激活，这至少部分地与紫草素诱导的自噬有关。此外，体内实验也显示了类似的结果：紫草素引起活性氧和磷酸化ERK的积累，从而诱导肿瘤异种移植模型中的自噬。这些结果表明紫草素是一种自噬诱导剂，可能是一种有前途的临床抗肿瘤药物。(C)2014爱思唯尔有限公司版权所有。
Shikonin, a naphthoquinone derived from the Chinese medicinal plant Lithospermum erythrornizon, shows potential to be a cancer chemotherapeutic agent. Our previous data demonstrate that high doses (about 6 mu M) of shikonin induce apoptosis in human hepatocellular carcinoma (HCC) cells. Here, we discovered that a low dose of shikonin (2.5 mu M) and a short treatment time (12 h) induced autophagy, as evidenced by the upregulation of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, the formation of acidic autophagic vacuoles (AVOs), and the punctate fluorescence pattern of GFP-LC3 protein. Next, we investigated the mechanism and found reactive oxygen species accumulation after shikonin treatment. The reactive oxygen species scavengers NAC and Tiron completely blocked autophagy. We further found activation of ERK by generation of reactive oxygen species and inhibition of RIP pathway, which are at least partially connected to shikonin-induced autophagy. Moreover, experiments in vivo revealed similar results: shikonin caused the accumulation of reactive oxygen species and phospho-ERK and thus induced autophagy in a tumor xenograft model. These findings suggest that shikonin is an inducer of autophagy and may be a promising clinical antitumor drug. (C) 2014 Elsevier B.V. All rights reserved.