CYTOTOXIC ACTIVITY AND TRANSFORMATION OF BALB C 3T3 CELLS IN-VITRO BYTHE INSECTICIDE ACEPHATE/

Cytotoxic and cell transforming activity of the organophosphate insect icide acephate have been studied in an in vitro experimental model whi ch foresees the exposure of BALB/c 3T3 cells to the chemical. The assa y was performed in the presence or absence of metabolic activation sys tem derived from phenobarbital and beta-naphthoflavone induced rats (S 9-mix). Cytotoxicity of acephate was unaffected by the presence of the metabolizing fraction. Cell-transforming potential, evidenced through the induction of transformation foci, was observed at all tested dose s (i.e. 100, 200 and 400 mu g/ml) with or without exogenous bioactivat ion. This activity was related with cell proliferation since it was pa rticularly evident in a level-II cell transformation assay when the ce lls were allowed to perform active proliferative activity. These findi ngs, obtained in a medium-term (6-8 weeks) test, may contribute to a b etter understanding of the action of acephate in the multistep carcino genesis, proving more information on the oncogenic risk to humans.