Comparison of biological effects of different polycyclic aromatic hydrocarbons in lung cells of hamster and rat in vitro.

The cytotoxicity and frequencies of transformation induced by 5 environmental polycyclic aromatic hydrocarbons (PAH) in hamster (M3E3/C3) and rat (WRB K3) lung cells were compared. Both cell strains investigated here retain major metabolic characteristics of the target cells in vivo and are thus able to effectively metabolize, i.e. activate, PAH. Cytotoxic effects of the carcinogen were determined in colony-forming assays and the PAH tested induced dose-dependent cytotoxic responses in the M3E3/C3 and WRB cells. They could then be classified into strong and weak cytotoxicity. Compared to the hamster cell system, the WRB cells were generally shown to be more sensitive. The transforming capacity of the compounds was determined by a soft agar colony formation assay detecting cells with anchorage independency (AI). All PAH investigated induced transformation to AI growth in both cell systems. The transforming activity of the PAH, relative to benzo[a]pyrene (B[a]P) as a reference substance, was determined to facilitate their ranking. This order of transforming potency appears to be similar to that observed in animal studies.