HUMAN CELL-MEDIATED BENZO(A)PYRENE CYTO-TOXICITY AND MUTAGENICITY IN HUMAN-DIPLOID FIBROBLASTS

  • 1 January 1980
    • journal article
    • research article
    • Vol. 40  (11) , 4070-4075
Abstract
A human epithelial cell-mediated cytotoxicity and mutagenicity assay system for [the carcinogen] benzo(a)pyrene [B(a)P] was developed with human fibroblasts as the target cells. Lethally X-irradiated human kidney carcinoma-derived epithelial cells had constant levels of B(a)P-metabolizing activity and were cocultivated with target human skin fibroblasts (XP12BE), which lack excision repair capability for B(a)P-DNA adducts. Under optimal assay conditions, the frequency of mutations to 6-thioguanine resistance induced in the target XP12BE cells by B(a)P and the binding of tritium-labeled B(a)P to DNA were concentration dependent. High-pressure liquid chromatography analysis of enzymatically degraded B(a)P-DNA adducts revealed 2 peaks: a major peak (82%) which cochromatographed with the guanosine adduct-standard synthesized from anti-isomeric-7,8-dihydro-diol-9,10-epoxide of B(a)P; and a minor peak (18%) which cochromatographed with the guanosine adduct-standard synthesized from syn-isomeric-7,8-diol-9,10-epoxide of B(a)P. Human liver carcinoma- and lung carcinoma-derived cell lines that were capable of metabolizing B(a)P proved equal to or better than the kidney carcinoma-derived cell line in producing cytotoxic B(a)P metabolites in the cell-mediated cytotoxicity assay with target XP12BE cells.

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