Development And Application Of Tests With Human Derived Cells For The Detection Of Environmental Genotoxins.
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Date
1998-04
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Abstract
Two novel approaches are described, in which metabolically competent human derived cells were used for the detection of genotoxic effects of environmental carcinogens. In the first, human hepatoma (Hep G2) cells were used for micronucleus and single cells were used for micronucleus and single cell gel electrophoresis (SCGE) assays. These cells have retained the activities of phase I and phase II enzymes which are usually lost during cultivation. We demonstrated that these cells are suitable for the detection of the genotoxic effects of representatives of various classes of DNA-reactive procarcinogens such as benzo(a) pyrene (B(a)P), 2-amino-3-methylimidazo-[4,5-f]-quinoline (IQ), cyclophosphamide (CP), and N-nitrosodimethylamine (NDMA), isatidine and aflatoxin B1 (AFB1). Furthermore, we found that these tests also detect the mutagenic effects of rodent carcinogens such as safrole and hexamethylphosphoramide (HEMPA), which give negative results in conventional in vitro procedures. Additional experimental series showed that genotoxicity assays with Hep G2 cells are also useful for the detection of co- and antimutagens, in particular for compounds which act via induction of activating and detoxifying enzymes. In the second approach, a protocol for stable co-cultivation sandwich cultures with primary human hepatocytes was used. The cultivation of the cells under organotypical conditions leads to an extension of their life span and results in an improved expression of drug metabolising enzymes. Two different experimental models were developed: In the first, the induction of HPRT mutations in V-79 cells was used as an endpoint, in the seconds, single strand breaks were measured in human K562 cells in SCGE assays. Experiments which were carried out with B(a)P and 7,12-diemethylbenz(a)anthracene as model compounds indicate that in both systems positive results are obtained. In conclusion, our data show that tests with human Hep G2 cells as well as sandwich cultures with primary human liver cells are useful for the detection of environmental carcinogens and probably reflect their effects in humans better than conventional in vitro assays with metabolically incompetent cells which are currently used in most mutagenicity studies.
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Keywords
mutagenicity, human HepG2 cells, human HepG2 cells, primary human hepatocytes
Citation
Knasmuller S, Uhl M, Darroudi Firouz, Mersch-Sundermann V, Bader A, Sanyal R, Schwab Christina, Hietsch G, Parzefall W, A T Natarajan. Development And Application Of Tests With Human Derived Cells For The Detection Of Environmental Genotoxins. Indian Journal of Human Genetics. 1998 Apr; 4(2): 181-194.