Cell death via mitochondrial apoptotic pathway due to activation of Bax by lysosomal photodamage
Cell death via mitochondrial apoptotic pathway due to activation of Bax by lysosomal photodamage
复制标题
由于溶酶体光损伤激活 Bax，细胞通过线粒体凋亡途径死亡
DOI：
10.1016/j.freeradbiomed.2011.03.042
复制
发表时间：
2011-07-01
影响因子：
7.4
通讯作者：
Xing, Da
中科院分区：
文献类型：
--
作者：
Liu, Lei;Zhang, Zhenzhen;Xing, Da
溶酶体光敏剂已用于光动力疗法。这种光敏剂和光的组合引起溶酶体光损伤，诱导细胞死亡。溶酶体破坏可导致细胞凋亡，但其信号通路仍有待阐明。本研究利用优先在溶酶体中积累的光敏剂N-乙酰二氢卟酚e6（NPe 6）研究了溶酶体光损伤引起细胞凋亡的机制。采用实时单细胞分析法研究了NPe 6光动力处理（NPe 6-PDT）后活的人肺腺癌细胞（ASTC-a-1）的凋亡。我们的结果表明，NPe 6-PDT诱导活性氧（ROS）的快速产生。光动力学产生的ROS引起溶酶体的快速破坏，导致组织蛋白酶的释放，并且ROS清除剂维生素C和NAC阻止该作用。然后，在细胞凋亡过程中观察到以下时空序列的细胞事件：Bcl-2相关的X蛋白（Bax）激活，细胞色素c释放，caspase-9/-3激活。重要的是，Bax的激活被证明是这种凋亡机制中的关键事件，因为使用siRNA抑制内源性Bax可以显著抑制细胞色素c释放和caspase-9/-3激活，并保护细胞免于死亡。总之，这项研究表明，PDT与溶酶体光敏剂诱导Bax激活，随后启动线粒体凋亡途径。(C)2011 Elsevier Inc. All rights reserved.
Lysosomal photosensitizers have been used in photodynamic therapy. The combination of such photosensitizers and light causes lysosomal photodamage, inducing cell death. Lysosomal disruption can lead to apoptosis but its signaling pathways remain to be elucidated. In this study, N-aspartyl chlorin e6 (NPe6), an effective photosensitizer that preferentially accumulates in lysosomes, was used to study the mechanism of apoptosis caused by lysosomal photodamage. Apoptosis in living human lung adenocarcinoma cells (ASTC-a-1) after NPe6-photodynamic treatment (NPe6-PDT) was studied using real-time single-cell analysis. Our results demonstrated that NPe6-PDT induced rapid generation of reactive oxygen species (ROS). The photodynamically produced ROS caused a rapid destruction of lysosomes, leading to release of cathepsins, and the ROS scavengers vitamin C and NAC prevent the effects. Then the following spatiotemporal sequence of cellular events was observed during cell apoptosis: Bcl-2-associated X protein (Bax) activation, cytochrome c release, and caspase-9/-3 activation. Importantly, the activation of Bax proved to be a crucial event in this apoptotic machinery, because suppressing the endogenous Bax using siRNA could significantly inhibit cytochrome c release and caspase-9/-3 activation and protect the cell from death. In conclusion, this study demonstrates that PDT with lysosomal photosensitizer induces Bax activation and subsequently initiates the mitochondrial apoptotic pathway. (C) 2011 Elsevier Inc. All rights reserved.