||N-Nitrosodiethylamine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone Induced Morphological Transformation of C3H/10T1/2CL8 Cells Expressing Human Cytochrome P450 2A6.
Nesnow, S. ;
Beck, S. ;
Rosenblum, S. ;
Lasley, J. ;
Tiano, H. F. ;
||Environmental Health Research and Testing, Inc., Research Triangle Park, NC. ;National Inst. of Environmental Health Sciences, Research Triangle Park, NC. Environmental Carcinogenesis and Mutagenesis Branch. ;Gentest Corp., Woburn, MA.;Health Effects Research Lab., Research Triangle Park, NC.
||EPA-68-D1-0148 ;EPA-Y01-ES-00186; EPA/600/J-94/417;
Transformed cell line ;
C3H inbred mice ;
Genetic vectors ;
Cell division ;
Cytochrome P450 2A6 ;
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Transfection of specific genes into cells capable of expressing chemically induced morphological cell transformation provides a valuable approach to study the mechanisms of action of carcinogens. A human cytochrome P450 isozyme, CYP2A6, has been successfully expressed from a retroviral vector in transformable C3H/10T1/2(10T1/2) mouse embryo fibroblasts and these resulting 10T1/2 clones were evaluated for the cytotoxic and transforming activites of two nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosodiethylamine (DEN). 10T1/2 clone 29 cells, which expressed high levels of CYP2A6 activity, were responsive to the cytotoxic and morphological transforming effects of DEN or NNK on a concentration-related basis. In 10T1/2 clone 29 cells, DEN at 600 micrograms/ml decreased cell survival to 67%, and induced 0.5 type II & III foci/fish. NNK at 400 micrograms/ml administered to 10T1/2 cells and 10T1/2 clone 4 cells (infected with the vector but not expressing the CYP2A6 activity) were unresponsive. These results indicate that expression of a cDNA coding for cytochrome P450 in 10T1/2 cells can provide information about the role of the enzyme in the activities of chemical carcinogens and also increase the sensitivity of 10T1/2 cells to a larger number of classes of chemical carcinogens. (Copyright (c) 1994 Elsevier Science B.V.)