| Redox status of thioredoxin-1 （TRX1） determines the sensitivity of human liver carcinoma cells （HepG2） to arsenic trioxide-induced cell death |
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| 作者姓名： | Tian C Gao P Zheng Y Yue W Wang X Jin H Chen Q |
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| 作者单位： | [1]The Laboratory of Apoptosis and Cancer Biology, State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, The Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Datun Rd, Chao Yang District, Beo'ing 100101, China; [2]College of Life Sciences, Nan Kai University, Tianjin 300071, China; [3]Department of Neuro-Oncology, MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA |
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| 基金项目： | We are grateful to Dr Maryam Mehrpour （Laboratoire de Cytokines et Immunologie des tumeurs Humaines, In- stitut Gustave Roussy PR1 and IFR 54, Villejuif, France） and Nathan B Erdmann （Department of Pharmacology and Experimental Neuroscience and Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA） for their thoughtful comments. We wish to thank Dr Junji Yodoi （Departient of Biological Responses, Institute for Virus Research, Kyoto University, Japan） for his generous provision of thioredoxin mutant plasmid, and Mrs Jing Wang for her technical assistance in flow cytometry. This work was supported by grants from the National Proprietary Basic Research Program （973 program project, Nos. 2002CB513100 and 2004CB72000）, and a National Outstanding Young Investigator Fellowship （No.30325013） from NSFC awarded to Chen Q. |
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| 摘 要： | lntracellular redox homeostasis plays a critical role in determining tumor cells＇ sensitivity to drug-induced apoptosis. Here we investigated the role of thioredoxin-1 （TRX1）, a key component of redox regulation, in arsenic trioxide （AS2O3）-induced apoptosis. Over-expression of wild-type TRX1 in HepG2 cells led to the inhibition of As2O3-induced cytochrome c （cyto c） release, caspase activation and apoptosis, and down-regulation of TRX1 expression by RNAi sensitized HepG2 cells to As2O3-induced apoptosis. Interestingly, mutation of the active site of TRX1 from Cys^32/35 to Ser^32/35 converted this molecule from an apoptotic protector to an apoptotic promoter. In an effort to understand the mechanisms of this conversion, we used isolated mitochondria from mouse liver and found that recombinant wild-type TRX1 could protect mitochondria from the apoptotic changes. In contrast, the mutant form of TRX1 alone elicited mitochondria-related apoptotic changes, including the mitochondrial permeability transition pore （mPTP） opening, loss of mitochondrial membrane potential, and cyto c release from mitochondria. These apoptotic effects were inhibited by cyclosporine A （CsA）, indicating that mutant TRX1 targeted to mPTP. Alteration of TRX1 from its reduced form to oxidized form in vivo by 2,4-dinitrochlorobenzene （DNCB）, a specific inhibitor ofTRX reductase, also sensitized HepG2 cells to As203-induced apoptosis. These data suggest that TRX1 plays a central role in regulating apoptosis by blocking cyto c release, and inactivation of TRX1 by either mutation or oxidization of the active site cysteines may sensitize tumor cells to As2O3-induced apoptosis.
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| 关 键 词： | 肝癌 三氧化砷 线粒体 细胞色素 细胞凋亡 |
Redox status of thioredoxin-1 (TRX1) determines the sensitivity of human liver carcinoma cells (HepG2) to arsenic trioxide-induced cell death |
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| Tian C,Gao P,Zheng Y,Yue W,Wang X,Jin H,Chen Q.Redox status of thioredoxin-1 (TRX1) determines the sensitivity of human liver carcinoma cells (HepG2) to arsenic trioxide-induced cell death[J].Cell Research,2008,18(4):458-471. |
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| Authors: | Tian Changhai Gao Ping Zheng Yanhua Yue Wen Wang Xiaohui Jin Haijing Chen Quan |
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| Institution: | The Laboratory of Apoptosis and Cancer Biology, State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Datun Rd, Chao Yang District, Beijing 100101, China. |
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| Abstract: | Intracellular redox homeostasis plays a critical role in determining tumor cells' sensitivity to drug-induced apoptosis. Here we investigated the role of thioredoxin-1 (TRX1), a key component of redox regulation, in arsenic trioxide (As(2)O(3))-induced apoptosis. Over-expression of wild-type TRX1 in HepG(2) cells led to the inhibition of As(2)O(3)-induced cytochrome c (cyto c) release, caspase activation and apoptosis, and down-regulation of TRX1 expression by RNAi sensitized HepG(2) cells to As(2)O(3)-induced apoptosis. Interestingly, mutation of the active site of TRX1 from Cys(32/35) to Ser(32/35) converted this molecule from an apoptotic protector to an apoptotic promoter. In an effort to understand the mechanisms of this conversion, we used isolated mitochondria from mouse liver and found that recombinant wild-type TRX1 could protect mitochondria from the apoptotic changes. In contrast, the mutant form of TRX1 alone elicited mitochondria-related apoptotic changes, including the mitochondrial permeability transition pore (mPTP) opening, loss of mitochondrial membrane potential, and cyto c release from mitochondria. These apoptotic effects were inhibited by cyclosporine A (CsA), indicating that mutant TRX1 targeted to mPTP. Alteration of TRX1 from its reduced form to oxidized form in vivo by 2,4-dinitrochlorobenzene (DNCB), a specific inhibitor of TRX reductase, also sensitized HepG(2) cells to As(2)O(3)-induced apoptosis. These data suggest that TRX1 plays a central role in regulating apoptosis by blocking cyto c release, and inactivation of TRX1 by either mutation or oxidization of the active site cysteines may sensitize tumor cells to As(2)O(3)-induced apoptosis. |
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| Keywords: | thioredoxin-1 arsenic trioxide mitochondria cytochrome c apoptosis |
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