Role of mitochondrial cardiolipin peroxidation in apoptotic photokilling of 5-aminolevulinate-treated tumor cells
Role of mitochondrial cardiolipin peroxidation in apoptotic photokilling of 5-aminolevulinate-treated tumor cells
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DOI：
10.1016/j.abb.2004.09.025
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发表时间：
2005-01-15
影响因子：
3.9
通讯作者：
Girotti, AW
中科院分区：
文献类型：
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作者：
Kriska, T;Korytowski, W;Girotti, AW
在基于5-氨基乙酰丙酸（ALA）的光动力疗法（PDT）中，肿瘤细胞摄取的ALA代谢为原卟啉IX（PpIX），其敏化光损伤，导致凋亡或坏死细胞死亡。由于亲脂性PpIX起源于线粒体，我们推测，高度不饱和心磷脂（CL）的光过氧化作用，它锚定细胞色素c（cyt c）的内膜，是一个早期的促凋亡事件。作为最初的证据，PpIX敏化的脂质体CL的光氧化为氢过氧化物（CLOOH）的物种排除细胞色素C结合，但这可以恢复GSH/硒过氧化物酶（GPX 4）的治疗。进一步的支持来源于使用（i）COH-BR 1肿瘤细胞的线粒体GPX 4过表达克隆（7 G4）和（ii）ALA治疗方案（其中大多数细胞PpIX位于线粒体内部（Pr-1）或外部（Pr-2））观察到的位点特异性效应。致敏细胞暴露于致死光剂量，然后分析死亡机制和脂质过氧化氢（LOOH）水平。照射后Pr-1载体对照（VC）细胞在cyt c释放和caspase-3激活后自发死亡，而7 G4细胞高度耐受。照射后Pr-2 VC和7 G4细胞表现出可忽略的cyt c释放或caspase-3激活，并且两种类型均通过坏死而死亡。在Pr-1 7 G4细胞中，CLOOH（在细胞色素c释放之前很久检测到）的积累比Pr-1 VC细胞慢70%，这种慢化超过了所有其他LOOH。这些和相关的研究结果支持CL是一个关键的上游靶点，在ESTA依赖ALA-PDT诱导的细胞凋亡的假设。(C)2004爱思唯尔公司All rights reserved.
In 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT), ALA taken up by tumor cells is metabolized to protoporphyrin IX (PpIX), which sensitizes photodamage leading to apoptotic or necrotic cell death. Since lipophilic PpIX originates in mitochondria, we postulated that photoperoxidation Of highly unsaturated cardiolipin (CL), which anchors cytochrome c (cyt c) to the inner membrane, is an early proapoptotic event. As initial evidence, PpIX-sensitized photooxidation of liposomal CL to hydroperoxide (CLOOH) species precluded cyt c binding, but this could be reinstated by GSH/selenoperoxidase (GPX4) treatment. Further support derived from site-specific effects observed using (i) a mitochondrial GPX4-overexpressing clone (7G4) of COH-BR1 tumor cells, and (ii) an ALA treatment protocol in which most cellular PpIX is either inside (Pr-1) or outside (Pr-2) mitochondria. Sensitized cells were exposed to a lethal light dose, and then analyzed for death mechanism and lipid hydroperoxide (LOOH) levels. Irradiated Pr-1 vector control (VC) cells died apoptotically following cyt c release and caspase-3 activation, whereas 7G4 cells were highly resistant. Irradiated Pr-2 VC and 7G4 cells showed negligible cyt c release or caspase-3 activation, and both types died via necrosis. CLOOH (detected long before cyt c release) accumulated similar to70% slower in Pr-1 7G4 cells than in Pr-1 VC, and this slowdown exceeded that of all other LOOHs. These and related findings support the hypothesis that CL is a key upstream target in mitochondria-dependent ALA-PDT-induced apoptosis. (C) 2004 Elsevier Inc. All rights reserved.