Redox regulation in radiation-induced cytochrome c release from mitochondria of human lung carcinoma A549 cells
Redox regulation in radiation-induced cytochrome c release from mitochondria of human lung carcinoma A549 cells
复制标题
DOI：
10.1016/j.canlet.2008.11.021
复制
发表时间：
2009-05-08
期刊：
影响因子：
9.7
通讯作者：
Inanami, Osamu
中科院分区：
文献类型：
--
作者：
Ogura, Aki;Oowada, Shigeru;Inanami, Osamu
哺乳动物细胞中的线粒体通过释放细胞色素c到胞质溶胶中，在遗传毒剂诱导的细胞凋亡的内在途径中发挥重要作用，并且是活性氧（ROS）的主要来源。本研究的目的是研究线粒体活性氧是否参与辐射诱导的A549细胞凋亡信号。照射后用N-乙酰-L-半胱氨酸（NAC）处理抑制了线粒体细胞色素c的释放，但不影响Bcl-2、Bcl-X-L和Bax的表达水平，表明ROS的晚期产生触发了细胞色素c的释放。使用DCFDA（经典的ROS荧光探针）和MitoAR（一种新型的线粒体ROS探针）的实验表明，细胞内和线粒体ROS在X射线照射后6 h增强。此外，从A549细胞分离的线粒体的O-2（中心点）的生产能力进行了评估，通过ESR波谱结合自旋捕获试剂（CYPMPO）。当分离的线粒体与NADH、琥珀酸和CYPMPO孵育时，检测到由于CYPMPO-OOH的ESR谱。这种NADH/琥珀酸依赖的O-2（中心点）生产从线粒体的照射细胞显着增加，与未照射的细胞相比。这些结果表明，电离辐射增强O-2（-中心点），从线粒体生产触发细胞色素c在A549细胞的释放。(C)2008爱思唯尔爱尔兰有限公司保留所有权利。
Mitochondria in mammalian cells are well-known to play an important role in the intrinsic pathway of genotoxic-agent-induced apoptosis by releasing cytochrome c into cytosol and to be a major source of reactive oxygen species (ROS). The aim of this study was to examine whether mitochondrial ROS are involved in radiation-induced apoptotic signaling in A549 cells. Post-irradiation treatment with N-acetyl-L-cystein (NAC) inhibited cytochrome c release from mitochondria but did not affect expression levels of Bcl-2, Bcl-X-L and Bax, suggesting that late production of ROS triggered cytochrome c release. Experiments using DCFDA (a classical ROS fluorescence probe) and MitoAR (a novel mitochondrial ROS probe) demonstrated that intracellular and mitochondrial ROS were enhanced 6 h after X irradiation. Furthermore, the O-2(-center dot) production ability of mitochondria isolated from A549 cells was evaluated by ESR spectroscopy combined with a spin-trapping reagent (CYPMPO). When isolated mitochondria were incubated with NADH, succinate and CYPMPO, an ESR spectrum due to CYPMPO-OOH was detected. This NADH/succinate-dependent O-2(-center dot) production from mitochondria of irradiated cells was significantly increased in comparison with that of unirradiated cells. These results indicate that ionizing radiation enhances O-2(-center dot), production from mitochondria to trigger cytochrome c release in A549 cells. (C) 2008 Elsevier Ireland Ltd. All rights reserved.