Antagonist effects of Acrylamide on clastogenity of VP16

Abstract

We investigated on the Acrylamide (AA) capability of influencing the clastogenic effects of VP16, the topoisomerase II targeting drug, by performing sequential treatments in V79 Chinese hamster cells. The VP16 cytotoxicity resulted almost completely antagonized by preincubating cells with nontoxic concentrations of AA, as inferred by statistically significant differences versus response with VP16 alone. Moreover, the severe clastogenic effect of VP16, evidenced by the presence of complex structural chromosome aberrations and by high frequencies of micronulei and sister chromatid exchanges, was reduced by AA in a dose-dependent manner. For example, the frequency of micronucleated cells induced by VP16 was 24.9% , and it became 11.2% or 6.3% when cells were pretreated with 1mM or 5mM AA, respectively. These findings let us to suppose that AA interacts with topoisomerase II. To address this question, we performed the kDNA decatenation assay and found that nuclear extracts from cells treated with either VP16 or AA had reduced topoisomerase II activity, as demonstrated by an inability to convert kDNA from the catenated to the decatenated form; on the contrary, nuclear extracts from cells pretreated with AA and then with VP16 were able to convert kDNa to the decatenated form. Taken together, these results show that acrylamide can efficiently minimize the clastogenicity of VP16 and suggest that it plays a role in the inhibition of topoisomerase II.