Document Detail

Expression of NAD(P)H:quinone oxidoreductase 1 in HeLa cells: role of hydrogen peroxide and growth phase.
MedLine Citation:
PMID:  11567026     Owner:  NLM     Status:  MEDLINE    
The aim of this work was to study the role of H(2)O(2) in the regulation of NAD(P)H:quinone oxidoreductase 1 (NQO1, DT-diaphorase, EC ) with relation to cell density of HeLa cells cultures and the function played by NQO1 in these cells. Levels of NQO1 activity were much higher (40-fold) in confluent HeLa cells than in sparse cells, the former cells being much more resistant to H(2)O(2). Addition of sublethal concentrations of H(2)O(2) (up to 24 microm) produced a significant increase of NQO1 (up to 16-fold at 12 microm) in sparse cells but had no effect in confluent cells. When cells reached confluency in the presence of pyruvate, a H(2)O(2) scavenger, NQO1 activity was decreased compared with cultures grown to confluency without pyruvate. Inhibition of quinone reductases by dicumarol substantially decreased viability of confluent cells in serum-free medium. This is the first demonstration that regulation of NQO1 expression by H(2)O(2) is dependent on the cell density in HeLa cells and that endogenous generation of H(2)O(2) participates in the increase of NQO1 activity as cell density is higher. This enzyme is required to promote survival of confluent cells.
R I Bello; C Gómez-Díaz; F Navarro; F J Alcaín; J M Villalba
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2001-09-20
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  276     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2001 Nov 
Date Detail:
Created Date:  2001-11-23     Completed Date:  2002-01-10     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  44379-84     Citation Subset:  IM    
Departamento de Biologia Celular, Fisiologia e Inmunologia, Facultad de Ciencias, Universidad de Córdoba, Cordoba, 14071 Spain.
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MeSH Terms
Cell Division
Culture Media, Serum-Free
Cytosol / metabolism
Dicumarol / pharmacology
Enzyme Inhibitors / pharmacology
Hela Cells
Hydrogen Peroxide / pharmacology*
NAD(P)H Dehydrogenase (Quinone) / biosynthesis*
Time Factors
Reg. No./Substance:
0/Culture Media, Serum-Free; 0/Enzyme Inhibitors; 66-76-2/Dicumarol; 7722-84-1/Hydrogen Peroxide; EC Dehydrogenase (Quinone)

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