Alterations in expression of the DFF40 gene have been reported in some
cancers. This study is an in vitro study of the
therapeutic effects of gene transfer that lead to elevation in DFF40 expression within T-47D cells in the presence of
sulfonamide drugs. In this study, we have constructed a eukaryotic expression vector for DFF40 and transfected it into T-47D
cancer cells. We used real time RT-PCR to detect the expression of DFF40 and the MTT assay to determine effects of the
sulfonamide drugs
acetazolamide,
sulfabenzamide,
sulfathiazole and
sulfacetamide on cell viability in the presence of increased and normal DFF40 levels. Cell cycle distribution was assessed by
propidium iodide (PI) staining and the rates of apoptosis by
annexin V/PI staining. The
DNA laddering analysis was employed to evaluate apoptosis. We observed that overexpression of DFF40 was only effective in decreasing viability in cells incubated with
acetazolamide and
sulfabenzamide. There was enhanced apoptosis in these groups, particularly with
acetazolamide. The cell cycle distribution analysis showed that in the presence of
sulfonamide drugs there were no substantial changes in empty-vector or DFF40-transfected cells, except for those cells treated with
sulfabenzamide or
sulfathiazole. There was no
DNA laddering in cells that expressed the empty vector when incubated with
sulfonamide drugs. In contrast, we observed
DNA laddering in cells that expressed DFF40 in the presence of
acetazolamide. Our results have demonstrated that combinatorial use of some
sulfonamides such as
acetazolamide along with increased expression of DFF40 can potently kill
tumor cells via apoptosis and may be beneficial for treatment of some chemoresistant
cancers.