Mutagenicity of N-nitrosodiethanolamine in a V79-derived cell line expressing two human biotransformation enzymes.
N-nitrosodiethanolamine (NDELA) has demonstrated carcinogenic activity in various rodent models. However, it is negative or only weakly active in standard in vitro genotoxicity assays. This poor response might be due to the requirement of specific enzymes for its activation. Previous work indicated that cytochrome P450 (CYP) 2E1, alcohol dehydrogenases and sulphotransferases (SULTs) can convert NDELA into reactive metabolites. We report here that NDELA induces concentration-dependent gene mutations (at the hprt locus) in V79-hCYP2E1-hSULT1A1 cells, engineered for expression of human CYP2E1 and human SULT1A1, but is inactive in parental V79 cells. Mutagenicity of NDELA in V79-hCYP2E1-hSULT1A1 cells was abolished by the CYP2E1 inhibitor 1-aminobenzotriazole, but unaffected by the SULT1A1 inhibitor pentachlorophenol. The efficiency and specificity of these inhibitors was demonstrated in gene mutation assays using SULT- and CYP2E1-dependent reference mutagens, 2-nitropropane and N-nitrosodimethylamine, respectively. In this study, it is documented for the first time that NDELA can induce gene mutations in mammalian cells. Whereas human CYP2E1 was required for its activation, human SULT1A1 was not involved either in its activation or its inactivation in our cell model.
Liu
Yungang
Y
German Institute of Human Nutrition (DIfE) Potsdam-Rehbruecke, Department of Nutritional Toxicology, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany. yungang1@hotmail.com
Glatt
Hansruedi
H
D000818:Animals; D015239:Arylsulfotransferase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D019392:Cytochrome P-450 CYP2E1 / Q000235:genetics* / Q000378:metabolism; D065691:Cytochrome P-450 CYP2E1 Inhibitors; D004052:Diethylnitrosamine / Q000031:analogs & derivatives* / Q000633:toxicity; D004789:Enzyme Activation / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D009154:Mutation / Q000235:genetics*; D009595:Nitroparaffins / Q000633:toxicity; D011407:Propane / Q000031:analogs & derivatives / Q000633:toxicity
D065691:Cytochrome P-450 CYP2E1 Inhibitors; D004791:Enzyme Inhibitors; D009153:Mutagens; D009595:Nitroparaffins; C014129:N-nitrosodiethanolamine; D004052:Diethylnitrosamine; D019392:Cytochrome P-450 CYP2E1; D015239:Arylsulfotransferase; C117544:SULT1A1 protein, human; C016617:2-nitropropane; D011407:Propane