Reversal Of Multidrug Resistance Using Cyclosporin A

Abstract

Multidrug resistance is a phenomenon which occurs in cancer cells. These cells become resistant to the drug of treatment as well as resistant to other unrelated chemotherapeutic drugs. Previous studies have shown that calmodulin inhibitors and calcium channel blockers are able to reverse resistance in these cells when used in conjunction with the chemotherapeutic drug. In this study, the ability of the immunosuppressive drug, cyclosporin A to overcome cellular resistance to the chemotherapeutic drug vincristine was analyzed. The Chinese hamster cell line, DC-3F and its multidrug resistant variant, DC-3F/VCRd-5L were used. Analysis revealed that cyclosporin A caused complete reversal of multidrug resistance in resistant cells and caused increased sensitivity to vincristine in sensitive cells.