Cardiovascular Center, Antai Tian-Sheng Memorial Hospital, Pingtung 92843, Taiwan.
Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan.
Chem Biol Interact. 2014 Mar 25;211:44-53. doi: 10.1016/j.cbi.2014.01.008. Epub 2014 Jan 23.
The effects of shikonin on gastric cancer cells were investigated in this study. Exposure to shikonin reduced the viability of gastric cancer cells in a time- and dose-dependent manner. However, apoptosis was not observed in gastric cancer cell treatment with different concentrations of shikonin for 6h. By contrast, treatment with shikonin for 24h significantly induced apoptosis, as evidenced by the results of TUNEL assay and flow cytometry analysis in proportion to the concentration. Disruption of the mitochondrial membrane potential was observed in gastric cancer cells that were treated with shikonin for 6 and 24h. Pretreatment with necrostatin-1 recovered cell death and mitochondrial membrane potential in the 6h shikonin treatment, but not in the 24h shikonin treatment. Western blot results reveal enhanced p38 phosphorylation, downregulated AKT phosphorylation, and increased caspase3 and PARP cleavage in cells that were treated with shikonin for 24h, but not in cells treated for 6h. Shikonin also triggered reactive oxygen species (ROS) generation both in the 6 and 24h treatments. Pretreatment with N-acetylcysteine blocked shikonin-induced cell death. In summary, our findings suggest that shikonin, which may function as a promising agent in the treatment of gastric cancers, sequentially triggered necrosis or apoptosis through ROS generation in gastric cancer cells.
本研究探讨了紫草素对胃癌细胞的作用。暴露于紫草素以时间和剂量依赖的方式降低胃癌细胞的活力。然而，在不同浓度的紫草素处理胃癌细胞 6 小时后，未观察到细胞凋亡。相比之下，用紫草素处理 24 小时可显著诱导细胞凋亡，这可通过 TUNEL 检测和流式细胞术分析证实，且与浓度呈正相关。在 6 和 24 小时用紫草素处理的胃癌细胞中观察到线粒体膜电位破坏。用 necrostatin-1 预处理可恢复 6 小时紫草素处理的细胞死亡和线粒体膜电位，但不能恢复 24 小时紫草素处理的细胞死亡。Western blot 结果显示，用紫草素处理 24 小时的细胞中 p38 磷酸化增强，AKT 磷酸化下调，caspase3 和 PARP 切割增加，但处理 6 小时的细胞中无此现象。紫草素还可在 6 和 24 小时处理中引发活性氧（ROS）的产生。用 N-乙酰半胱氨酸预处理可阻断紫草素诱导的细胞死亡。总之，我们的研究结果表明，紫草素可能作为治疗胃癌的一种有前途的药物，通过在胃癌细胞中生成 ROS，依次触发坏死或凋亡。
