Specific downregulation of bcl-2 and xIAP by RNAi enhances the effects of chemotherapeutic agents in MCF-7 human breast cancer cells

Antiapoptotic genes such as bcl-2 or xlAP may be responsible for resistance to apoptosis induced by cytotoxic drugs. The aim of this study was to investigate if downregulation of bcl-2 or xlAP by RNA interference (RNAi) would sensitize MCF-7 cells to etoposide and doxorubicin. FlTC-siRNAs uptake was verified by fluorescence microscopy and downregulation of Bcl-2 or XlAP was confirmed by Western Blotting. Both siRNAs reduced the number of viable cells and increased cellular apoptosis. Treatment with siRNAs followed by treatment with etoposide or doxorubicin further reduced the number of viable cells, when compared to either of the treatments alone. Therefore, downregulation of bcl-2 or xlAP by RNAi enhances the effects of etoposide and doxorubicin.