Source:http://linkedlifedata.com/resource/pubmed/id/16910775
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
7-8
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| pubmed:dateCreated |
2006-8-16
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| pubmed:abstractText |
This study investigates the hypothesis that Mn-superoxide dismutase (MnSOD) influences cancer cell radiosensitivity by regulating the G(2)-checkpoint pathway. Human oral squamous carcinoma cells (SCC25) stably overexpressing MnSOD were irradiated (6 Gy) and assayed for cell survival, cell-cycle phase distributions, and bromodeoxyuridine (BrdU) pulse-chase flow-cytometric measurements of cell-cycle phase transits. Electron paramagnetic resonance (EPR) spectroscopy was used to measure steady-state levels of oxygen-centered free radicals. Glutathione and glutathione disulfide levels were used as indicators of changes in the intracellular redox state. MnSOD overexpression increased radioresistance threefold to fourfold; this increase was associated with twofold to threefold increases in radiation-induced G(2) accumulation. BrdU pulse-chase and flow-cytometric measurements of the percentage of G(1) and relative movement showed no significant changes in G(1) and S transits; however, the percentage of G(2) cells and BrdU-positive cells showed delayed G(2)+M transits in MnSOD-overexpressing irradiated cells. The steady-state levels of oxygen-centered free radicals were not significantly different in vector compared with MnSOD-overexpressing cells, suggesting that the free radical generation is essentially similar. MnSOD overexpression did prevent radiation-induced decreases in total glutathione content, which correlated with radioresistance and enhanced G(2) accumulation. These results support the hypothesis that a "metabolic redox-response" to IR exposure regulates radiosensitivity by altering radiation-induced G(2) accumulation.
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| pubmed:grant | |
| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Bromodeoxyuridine,
http://linkedlifedata.com/resource/pubmed/chemical/Free Radicals,
http://linkedlifedata.com/resource/pubmed/chemical/Glutathione,
http://linkedlifedata.com/resource/pubmed/chemical/Glutathione Disulfide,
http://linkedlifedata.com/resource/pubmed/chemical/Superoxide Dismutase
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| pubmed:status |
MEDLINE
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| pubmed:issn |
1523-0864
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
8
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
1273-81
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| pubmed:dateRevised |
2007-11-14
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| pubmed:meshHeading |
pubmed-meshheading:16910775-Bromodeoxyuridine,
pubmed-meshheading:16910775-Carcinoma, Squamous Cell,
pubmed-meshheading:16910775-Cell Cycle,
pubmed-meshheading:16910775-Cell Survival,
pubmed-meshheading:16910775-Electron Spin Resonance Spectroscopy,
pubmed-meshheading:16910775-Flow Cytometry,
pubmed-meshheading:16910775-Free Radicals,
pubmed-meshheading:16910775-G2 Phase,
pubmed-meshheading:16910775-Gene Expression Regulation, Enzymologic,
pubmed-meshheading:16910775-Gene Expression Regulation, Neoplastic,
pubmed-meshheading:16910775-Glutathione,
pubmed-meshheading:16910775-Glutathione Disulfide,
pubmed-meshheading:16910775-Humans,
pubmed-meshheading:16910775-Mouth Neoplasms,
pubmed-meshheading:16910775-Oxidation-Reduction,
pubmed-meshheading:16910775-Radiation Tolerance,
pubmed-meshheading:16910775-Superoxide Dismutase,
pubmed-meshheading:16910775-Time Factors
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| pubmed:articleTitle |
Mn-superoxide dismutase overexpression enhances G2 accumulation and radioresistance in human oral squamous carcinoma cells.
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| pubmed:affiliation |
Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, 52242, USA.
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| pubmed:publicationType |
Journal Article,
Research Support, N.I.H., Extramural
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