Document Detail

Disruption of redox homeostasis in the transforming growth factor-alpha/c-myc transgenic mouse model of accelerated hepatocarcinogenesis.
MedLine Citation:
PMID:  9624185     Owner:  NLM     Status:  MEDLINE    
In previous studies we have demonstrated that transforming growth factor (TGF)-alpha/c-myc double transgenic mice exhibit an enhanced rate of cell proliferation, accumulate extensive DNA damage, and develop multiple liver tumors between 4 and 8 months of age. To clarify the biochemical events that may be responsible for the genotoxic and carcinogenic effects observed in this transgenic model, several parameters of redox homeostasis in the liver were examined prior to development of hepatic tumors. By 2 months of age, production of reactive oxygen species, determined by the peroxidation-sensitive fluorescent dye, 2',7'-dichlorofluorescin diacetate, was significantly elevated in TGF-alpha/c-myc transgenic hepatocytes versus either wild type or c-myc single transgenic cells, and occurred in parallel with an increase in lipid peroxidation. Concomitantly with a rise in oxidant levels, antioxidant defenses were decreased, including total glutathione content and the activity of glutathione peroxidase, whereas thioredoxin reductase activity was not changed. However, hepatic tumors which developed in TGF-alpha/c-myc mice exhibited an increase in thioredoxin reductase activity and a very low activity of glutathione peroxidase. Furthermore, specific deletions were detected in mtDNA as early as 5 weeks of age in the transgenic mice. These data provide experimental evidence that co-expression of TGF-alpha and c-myc transgenes in mouse liver promotes overproduction of reactive oxygen species and thus creates an oxidative stress environment. This phenomenon may account for the massive DNA damage and acceleration of hepatocarcinogenesis observed in the TGF-alpha/c-myc mouse model.
V M Factor; A Kiss; J T Woitach; P J Wirth; S S Thorgeirsson
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  273     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1998 Jun 
Date Detail:
Created Date:  1998-07-09     Completed Date:  1998-07-09     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  15846-53     Citation Subset:  IM    
Laboratory of Experimental Carcinogenesis, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
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MeSH Terms
DNA Damage
DNA, Mitochondrial / metabolism
Disease Models, Animal
Gene Expression Regulation, Neoplastic
Homeostasis / genetics*
Liver Neoplasms, Experimental / genetics,  physiopathology*
Mice, Transgenic
Oxidative Stress / genetics*
Proto-Oncogene Proteins c-myc / genetics*
Reactive Oxygen Species / metabolism
Signal Transduction
Transforming Growth Factor alpha / genetics*
Reg. No./Substance:
0/DNA, Mitochondrial; 0/Proto-Oncogene Proteins c-myc; 0/Reactive Oxygen Species; 0/Transforming Growth Factor alpha

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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