Interactions of chrysotile and benzopyrene in a human cell culture systems

The risk of lung cancer related to asbestos exposure has been shown to increase disproportionately by cigarette smoking, suggesting a synergistic effect. Differing lengths of NIEHS chrysotile with benzopyrene [B(a)P, B(e)P] (organic by-products of combustion) were applied on normal human fibroblasts (cell line CI) to test for cytotoxicity (survival determined by colony-forming efficiency), binding of benzopyrene to DNA, and the production of benzopyrene metabolites. At concentrations of 100 micrograms/mL, NIEHS short chrysotile was more cytotoxic than NIEHS intermediate chrysotile (3% and 17% survival, respectively); B(a)P and B(e)P concentrations up to and including 10 microM were not cytotoxic. Simultaneous application of NIEHS short chrysotile with B(a)P or B(e)P did not decrease survival synergistically. On the contrary, application of B(a)P simultaneously with NIEHS intermediate chrysotile resulted in increased survival over that of intermediate chrysotile alone (25% and 17% survival, respectively). There were low levels of B(a)P bound to DNA in the presence of NIEHS short chrysotile or NIEHS intermediate chrysotile. Measurable levels of B(a)P-DNA adducts were formed both in the absence and in the presence of each size of NIEHS chrysotile. However, there was no strong indication of a perturbation of the level of DNA-B(a)P binding following simultaneous administration of increasing levels of asbestos in addition to 1 microM hydrocarbon. The asbestos had no demonstrable influence on the level of B(a)P metabolism during the 24-hr period following simultaneous exposure of asbestos and hyrdocarbons.(ABSTRACT TRUNCATED AT 250 WORDS)