Section of Forensic Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
Toxicol In Vitro. 2011 Dec;25(8):1581-7. doi: 10.1016/j.tiv.2011.05.028. Epub 2011 Jun 2.
Chelerythrine, formerly identified as a protein kinase C inhibitor, has also been shown to inhibit the anti-apoptotic Bcl-2 family proteins. However, recent studies have now demonstrated that chelerythrine can induce the loss of mitochondrial membrane potential (ΔΨm), a membrane permeability transition (MPT), and the subsequent activation of the mitochondrial apoptotic pathway, even in the cells deficient in Bax and Bak. This suggests the existence of an alternative Bax/Bak-independent pathway for apoptosis. The generation of reactive oxygen species (ROS) from the mitochondrial electron transport chain (ETC) is also implicated in the cytotoxity elicited by chelerythrine. In our current study, we show that chelerythrine induces the rapid apoptotic death of H9c2 cardiomyocyte-derived cells within 8 min of treatment. The proteolytic activation of caspase9 and caspase3, crucial mediators of the mitochondrial apoptotic pathway, are also observed within 6 min of exposure to this drug. The generation of ROS is detected but at only marginal levels in the treated cells. The inhibition of the mitochondrial ETC by rotenone and malonate had almost no effects on ROS generation but in both cases effectively inhibited both cell death and the caspase activation induced by chelerythrine. Hence, chelerythrine initiates the rapid mitochondrial apoptotic death of H9c2 cardiomyoblastoma cells in a manner that is likely independent of the generation of ROS from mitochondria.
白屈菜红碱，最初被鉴定为蛋白激酶 C 抑制剂，也被证明能抑制抗凋亡 Bcl-2 家族蛋白。然而，最近的研究表明，白屈菜红碱能诱导线粒体膜电位（ΔΨm）丧失、膜通透性转换（MPT），以及随后激活线粒体凋亡途径，即使在 Bax 和 Bak 缺失的细胞中也是如此。这表明存在一种替代的 Bax/Bak 非依赖性凋亡途径。线粒体电子传递链（ETC）产生的活性氧物种（ROS）也与白屈菜红碱引起的细胞毒性有关。在我们目前的研究中，我们表明白屈菜红碱在处理后 8 分钟内诱导 H9c2 心肌细胞衍生细胞的快速凋亡死亡。线粒体凋亡途径的关键介质 caspase9 和 caspase3 的蛋白水解激活也在接触这种药物后 6 分钟内被观察到。ROS 的产生被检测到，但在处理细胞中仅处于边缘水平。鱼藤酮和丙二酸抑制线粒体 ETC 对 ROS 的产生几乎没有影响，但在这两种情况下，都能有效抑制白屈菜红碱诱导的细胞死亡和半胱天冬酶激活。因此，白屈菜红碱以一种可能不依赖于线粒体产生 ROS 的方式启动 H9c2 心肌母细胞瘤细胞的快速线粒体凋亡死亡。
