Reactive Oxygen Species Regulate Caspase Activation in Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand–Resistant Human Colon Carcinoma Cell Lines
| Autor: | Addison Delaney, Leslie Douglas, David M. Tillman, Kamel Izeradjene, Janet A. Houghton |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Carbonyl Cyanide m-Chlorophenyl Hydrazone
Cancer Research Programmed cell death Cell Respiration Apoptosis X-Linked Inhibitor of Apoptosis Protein Caspase 3 Mitochondrion Inhibitor of apoptosis Antioxidants Oxidative Phosphorylation Mitochondrial Proteins TNF-Related Apoptosis-Inducing Ligand Bcl-2-associated X protein Cell Line Tumor Humans Caspase bcl-2-Associated X Protein chemistry.chemical_classification Reactive oxygen species Membrane Glycoproteins biology Tumor Necrosis Factor-alpha Uncoupling Agents Intracellular Signaling Peptides and Proteins Cytochromes c Proteins Caspase Inhibitors Acetylcysteine Mitochondria Cell biology Enzyme Activation Isoenzymes Proto-Oncogene Proteins c-bcl-2 Oncology Biochemistry chemistry Drug Resistance Neoplasm Caspases Colonic Neoplasms biology.protein Apoptosis Regulatory Proteins Carrier Proteins Reactive Oxygen Species |
| Zdroj: | Cancer Research. 65:7436-7445 |
| ISSN: | 1538-7445 0008-5472 |
| DOI: | 10.1158/0008-5472.can-04-2628 |
| Popis: | The effects of reactive oxygen species (ROS) on tumor necrosis factor–related apoptosis–inducing ligand (TRAIL)–induced apoptosis in solid cancers have yet to be clearly defined. In this study, we found that the classic uncoupler of oxidative phosphorylation, carbonyl cyanide m-chlorophenylhydrazone (CCCP), induced a reduction in ΔΨm and generation of ROS. This uncoupling effect enhanced TRAIL-induced apoptosis in TRAIL-resistant human colon carcinoma cell lines (RKO, HT29, and HCT8). Sensitization was inhibited by benzyloxycarbonyl-valine-alanine-aspartate fluoromethylketone, indicating the requirement for caspase activation. CCCP per se did not induce apoptosis or release of proapoptotic factors from mitochondria. Generation of ROS by CCCP was responsible for TRAIL-induced Bax and caspase activation because scavenging ROS completely abrogated apical caspase-8 activation and further downstream events leading to cell death. Overexpression of Bcl-2 did not prevent the initial loss of ΔΨm and ROS generation following CCCP treatment, but did prevent cell death following TRAIL and CCCP exposure. Uncoupling of mitochondria also facilitated TRAIL-induced release of proapoptotic factors. X-linked inhibitor of apoptosis overexpression abrogated TRAIL-induced apoptosis in the presence of CCCP and decreased initiator procaspase-8 processing, indicating that additional processing of caspase-8 required initiation of a mitochondrial amplification loop via effector caspases. Of interest, depletion of caspase-9 in RKO cells did not protect cells from TRAIL/CCCP-induced apoptosis, indicating that apoptosis occurred via a caspase-9–independent pathway. Data suggest that in the presence of mitochondrial-derived ROS, TRAIL induced mitochondrial release of Smac/DIABLO and inactivation of X-linked inhibitor of apoptosis through caspase-9–independent activation of caspase 3. |
| Databáze: | OpenAIRE |
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