Comparison of the effects of valproic acid and levetiracetam on apoptosis in the human ovarian cancer cell line OVCAR-3

Abstract

BackgroundWe have previously shown that due to its cytotoxic and cytostatic activities, valproic acid (VPA), but not levetiracetam (LEV), may have potential as a drug for treating human ovarian cancer. In the present study, we compare apoptotic mechanisms including gene and protein expression in the human ovarian cancer cell line, OVCAR-3, following exposure to VPA and LEV. MethodsCells were cultured with VPA or LEV at concentrations between 0.1mM and 10mM. Apoptosis was assessed by DNA fragmentation assay and expression of apoptosis-regulatory genes determined by real-time PCR and confirmed by western blotting. Time-dependent effects of VPA and LEV on activity of caspases (-3, -8 and -9) activity were evaluated by fluorescent assay and western blotting. ResultsExposure to VPA at concentrations above 5mM resulted in an increase in DNA fragmentation, modulated expression of genes and proteins associated with apoptosis and activated caspase ca scade. Exposure to LEV, however, did not affect DNA fragmentation and modulation of the mechanisms of apoptosis was not observed in LEV-treated cells at all doses used. ConclusionsExposure to high concentrations of VPA significantly stimulated apoptosis, by modulating the expression of genes and proteins responsible for cell death and also by activation of caspases cascade. Such effects were not observed with LEV. These data suggest that VPA should be seriously evaluated as an anti-cancer drug for ovarian cancer.