Enhancement of adenovirus transformation by pretreatment of hamster cells with carcinogenic polycyclic hydrocarbons.

Abstract

Summary Treatment of hamster embryo cells with benzo( a )pyrene, 3-methylcholanthrene, 7,12-dimethylbenz(a)anthracene, dibenz(a,h)anthracene, or dibenz(a,c)anthracene for 18 hr prior to the addition of an oncogenic adenovirus, SA7, enhanced the frequency of viral transformation. However, treatment of cells 5 hr after virus addition resulted in inhibition of transformation. The noncarcinogenic polycyclic hydrocarbons, phenanthrene, pyrene, and perylene, failed to stimulate SA7 transformation. The enhancement of transformation was directly related to chemical concentration, but treatment of cells with concentrations of chemicals above those necessary to demonstrate maximal enhancement resulted in a decrease in enhancement or complete inhibition of viral transformation. The increase in transformation frequency was not due to the selection of transformation-sensitive cells, since 6-fold increases in SA7 foci were observed in the absence of cell death. The data indicate that the stimulation of viral transformation resulted from a direct effect of the chemicals upon the cells, increasing their sensitivity to adenovirus transformation.