ENHANCING CYTOTOXIC EFFECT OF CALCIUM ANTAGONISTS ON ANTICANCER AGENTS IN HUMAN RENAL CELL CARCINOMA CELLS IN VITRO

Abstract

We have examined the enhancing cytotoxic effect of calcium antagonists on vinblastine (VLB) and doxorubicin hydrochloride (ADM) in human renal cell carcinoma cells (KN41, 5873T, YCR-1) by the in vitro colony formation assay. The calcium antagonists, nicardipine, verapamil, prenylamine, and nifedipine were used at a nontoxic concentration of 10μM. Nicardipine enhanced the cytotoxicity of VLB and ADM in three human renal cell carcinoma cell lines. The enhancement was more potent with VLB than ADM. A 4.5-to 16-fold increase in VLB cytotoxity was observed in thses cell lines with nicardipine. Other calcium antagonists, verapamil, prenylamine, and nifedipine, also enhanced the cytotoxity of VLB to KN41.