Rat liver epithelial cells express functional cytochrome P450 2E1

• Published in: Carcinogenesis (New York) 1996-05, Vol.17 (5), p.1101-1106
• Main Authors: Lerche, Carole, Le Jossic, Catherine, Fautrel, Alain, de Waziers, Isabelle, Ballet, François, Guillouzo, Andre, Corcos, Laurent
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Blotting, Western; Cytochrome P-450 CYP2E1; Cytochrome P-450 Enzyme System - genetics; Cytochrome P-450 Enzyme System - metabolism; Enzymes and enzyme inhibitors; Epithelium - enzymology; Fundamental and applied biological sciences. Psychology; Liver - enzymology; Male; Oxidoreductases; Oxidoreductases, N-Demethylating - genetics; Oxidoreductases, N-Demethylating - metabolism; Promoter Regions, Genetic; Rats; Rats, Inbred F344; Rats, Sprague-Dawley; RNA, Messenger - analysis
• ISSN: 0143-3334; 1460-2180
• DOI: 10.1093/carcin/17.5.1101

Rat liver epithelial cells (RLECs) isolated by trypsinization of the livers of normal 10 day old rats are largely used in co-culture with primary hepatocytes. The aim of the present study was to investigate the expression of biotransformation enzyme-encoding genes in three preparations of RLEC lines. Although no expression of cytochrome P450 1A1/2 (CYP1A1/2), CYP2B1/2, CYP2C6 or CYP3A mRNAs could be detected, we found that all of the different preparations of RLECs expressed a high level of CYP2E1 mRNA. We demonstrated the presence of the CYP2E1 apoprotein in microsomes of RLECs by immunoblot analyses, together with chlorzoxazone 6-hydroxylation, an activity known to be mainly catalyzed by CYP2E1. In addition, acetone treatment of these cells resulted in an increase in both CYP2E1 apoprotein and chlorzoxazone 6-hydroxylation activity levels. Finally, we showed the susceptibility of RLECs to N-methyl formamide- and diethylnitrosamine-induced toxicity, suggesting metabolic activation by CYP2E1. Thus, RLECs may cooperate with hepatocytes to CYP2El-mediated metabolism in the co-culture model. In addition, transfection experiments with a CYP2E1 promoter construct, in which the proximal 539 bp containing the binding site for HNF1α were inserted upstream of the chloramphenicol acetyl transferase gene, demonstrated a strong induction upon co-transfection with an HNF1α expression plasmid. Thus, RLECs provide a useful tool for studying metabolism and cytotoxicity of CYP2E1 substrates in the absence of other expressed CYPs, and for analyzing CYP2E1 promoter function.