Document Detail


A NADPH oxidase-dependent redox signaling pathway mediates the selective radiosensitization effect of parthenolide in prostate cancer cells.
MedLine Citation:
PMID:  20233868     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cancer cells are usually under higher oxidative stress compared with normal cells. We hypothesize that introducing additional reactive oxygen species (ROS) insults or suppressing antioxidant capacity may selectively enhance cancer cell killing by oxidative stress-generating agents through stress overload or stress sensitization, whereas normal cells may be able to maintain redox homeostasis under exogenous ROS by adaptive response. Here, we show that parthenolide, a sesquiterpene lactone, selectively exhibits a radiosensitization effect on prostate cancer PC3 cells but not on normal prostate epithelial PrEC cells. Parthenolide causes oxidative stress in PC3 cells but not in PrEC cells, as determined by the oxidation of the ROS-sensitive probe H(2)DCFDA and intracellular reduced thiol and disulfide levels. In PC3 but not PrEC cells, parthenolide activates NADPH oxidase, leading to a decrease in the level of reduced thioredoxin, activation of phosphoinositide 3-kinase/Akt, and consequent FOXO3a phosphorylation, which results in the downregulation of FOXO3a targets antioxidant enzyme manganese superoxide dismutase and catalase. Importantly, when combined with radiation, parthenolide further increases ROS levels in PC3 cells whereas it decreases radiation-induced oxidative stress in PrEC cells, possibly by increasing reduced glutathione levels. Together, the results show that parthenolide selectively activates NADPH oxidase and mediates intense oxidative stress in prostate cancer cells by both increasing ROS generation and decreasing antioxidant defense capacity. The results support the concept of exploiting the intrinsic differences in the redox status of cancer cells and normal cells as targets for selective cancer killing.
Authors:
Yulan Sun; Daret K St Clair; Yong Xu; Peter A Crooks; William H St Clair
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-03-16
Journal Detail:
Title:  Cancer research     Volume:  70     ISSN:  1538-7445     ISO Abbreviation:  Cancer Res.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-02     Completed Date:  2010-05-03     Revised Date:  2013-05-29    
Medline Journal Info:
Nlm Unique ID:  2984705R     Medline TA:  Cancer Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2880-90     Citation Subset:  IM    
Affiliation:
Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA.
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MeSH Terms
Descriptor/Qualifier:
Catalase / metabolism
Cell Line, Tumor
Enzyme Activation / drug effects
Forkhead Transcription Factors / metabolism
Glutathione / metabolism
Humans
Male
NADPH Oxidase / metabolism*
Oncogene Protein v-akt / metabolism
Oxidation-Reduction
Oxidative Stress / drug effects
Phosphatidylinositol 3-Kinases / metabolism
Phosphorylation / drug effects
Prostatic Neoplasms / drug therapy,  enzymology*,  radiotherapy
Radiation-Sensitizing Agents / pharmacology*
Sesquiterpenes / pharmacology*
Signal Transduction
Superoxide Dismutase / metabolism
Thioredoxins / metabolism
Grant Support
ID/Acronym/Agency:
CA115801/CA/NCI NIH HHS; CA49797/CA/NCI NIH HHS; R01 CA115801-03/CA/NCI NIH HHS; R01 CA115801-05/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/FOXO3 protein, human; 0/Forkhead Transcription Factors; 0/Radiation-Sensitizing Agents; 0/Sesquiterpenes; 2RDB26I5ZB/parthenolide; 52500-60-4/Thioredoxins; 70-18-8/Glutathione; EC 1.11.1.6/Catalase; EC 1.15.1.1/Superoxide Dismutase; EC 1.6.3.1/NADPH Oxidase; EC 2.7.1.-/Phosphatidylinositol 3-Kinases; EC 2.7.11.1/Oncogene Protein v-akt
Comments/Corrections

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