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Peroxide is a key mediator of Bcl-2 down-regulation and apoptosis induction by cisplatin in human lung cancer cells.

Authors
Wang-L; Chanvorachote-P; Toledo-D; Stehlik-C; Mercer-RR; Castranova-V; Rojanasakul-Y
Source
Mol Pharmacol 2008 Jan; 73(1):119-127
NIOSHTIC No.
20033185
Abstract
Susceptibility to apoptosis is an essential prerequisite for successful eradication of tumor cells by chemotherapy. Consequently, resistance to apoptosis has been established as one of the mechanisms responsible for the failure of therapeutic approaches in many types of cancers. In the present study, we investigated the susceptibility of human lung cancer H460 cells to apoptotic cell death induced by cisplatin and determined its regulatory mechanisms. Treatment of the cells with cisplatin induced rapid generation of multiple oxidative species and a concomitant increase in apoptotic cell death. Apoptosis induced by cisplatin was mediated through the mitochondrial death pathway, which requires caspase-9 activation and is regulated by Bcl-2. Cisplatin induced down-regulation of Bcl-2 through a process that involves dephosphorylation and ubiquitination of the protein, which facilitates its degradation by proteasome. This down-regulation was inhibited by antioxidant enzymes catalase and glutathione peroxidase (H(2)O(2) scavenger), but not by superoxide dismutase (O(2)(.) scavenger) or deferoxamine (OH. inhibitor). Electron spin resonance and flow cytometric analyses showed the formation of H(2)O(2) along with O(2)(.) and OH. radicals after cisplatin treatment. H(2)O(2) was generated in part by dismutation of O(2)(.) and served as a precursor for OH.. Together, our results indicate an essential role of H(2)O(2) in the regulation of Bcl-2 and apoptotic cell death induced by cisplatin. Because aberrant expression of Bcl-2 has been associated with death resistance of cancer cells to chemotherapy, the results of this study could be used to aid the design of more effective strategies for cancer treatment.
Keywords
Cell-function; Cellular-function; Lung-cancer; Lung-cells; Lung-disease; Lung-disorders; Chemoreceptors; Chemotherapy; Treatment; Cellular-transport-mechanism
Contact
Y Rojanasakul, W Virginia University, Department Pharmaceutical Science, PO Box 9530, Morgantown, WV 26506
CODEN
MOPMA3
CAS No.
15663-27-1
Publication Date
20080101
Document Type
Journal Article
Email Address
yrojan@hsc.wvu.edu
Fiscal Year
2008
NTIS Accession No.
NTIS Price
Issue of Publication
1
ISSN
0026-895X
NIOSH Division
HELD
Priority Area
Manufacturing
Source Name
Molecular Pharmacology
State
WV; IL
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