Document Detail


CYP3A4 catalytic activity is induced in confluent Huh7 hepatoma cells.
MedLine Citation:
PMID:  20233841     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Drug-induced hepatotoxicity is an important cause for disapproval, limitations of use, or withdrawal of drugs, and there is a high need for reproducible in vitro systems that can predict such toxicity. In this study, we show that confluent growth of the human hepatoma cell line Huh7 up to 5 weeks results in increased gene expression of several cytochromes P450 (P450s), UDP-glucuronosyltransferases, transporters, transcription factors, and several liver-specific genes, as measured by low-density array. The most striking effect was seen for CYP3A4 expression. Western blot analysis revealed increased amounts of CYP3A4 together with increased levels of NADPH-P450 reductase, cytochrome b(5), and albumin with prolonged time of confluence. By using the CYP3A4-specific substrates luciferin 6' benzyl ether, testosterone, and midazolam, we could confirm that the increased CYP3A4 gene expression also was accompanied by a similar increase in catalytic activity, inhibitable by the CYP3A4-selective inhibitor ketoconazole. The CYP3A4 activity in confluent cells was also inducible by rifampicin. Finally, the cell system could support the CYP3A4-dependent hepatotoxic activation of aflatoxin B(1), which was effectively inhibited by ketoconazole. Our results show that Huh7 cells grown confluent differentiate into a more metabolically competent cell line, especially with regard to CYP3A4.
Authors:
Louise Sivertsson; Monica Ek; Malin Darnell; Irene Edebert; Magnus Ingelman-Sundberg; Etienne P A Neve
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-03-16
Journal Detail:
Title:  Drug metabolism and disposition: the biological fate of chemicals     Volume:  38     ISSN:  1521-009X     ISO Abbreviation:  Drug Metab. Dispos.     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-05-14     Completed Date:  2010-08-20     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9421550     Medline TA:  Drug Metab Dispos     Country:  United States    
Other Details:
Languages:  eng     Pagination:  995-1002     Citation Subset:  IM    
Affiliation:
Department of Physiology and Pharmacology, Section of Pharmacogenetics, Karolinska Institutet, Nanna Svartz väg 2, SE-171 77 Stockholm, Sweden. Louise.Sivertsson@ki.se
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MeSH Terms
Descriptor/Qualifier:
Aflatoxin B1
Catalysis
Cell Line
Cell Line, Tumor
Cytochrome P-450 CYP3A / biosynthesis,  metabolism*
Cytochrome P-450 Enzyme System / isolation & purification,  metabolism
Drug Interactions
Gene Expression
Humans
Ketoconazole / metabolism
Microsomes, Liver / metabolism*
Midazolam
Rifampin
Testosterone
Transcription Factors
Chemical
Reg. No./Substance:
0/Transcription Factors; 1162-65-8/Aflatoxin B1; 13292-46-1/Rifampin; 58-22-0/Testosterone; 59467-70-8/Midazolam; 65277-42-1/Ketoconazole; 9035-51-2/Cytochrome P-450 Enzyme System; EC 1.14.13.67/CYP3A4 protein, human; EC 1.14.14.1/Cytochrome P-450 CYP3A

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


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