[Enhanced cytotoxic effect of Adriamycin and vincristine against PC-6 (human lung cancer cell line) and Hattori (human breast cancer cell line)].

Enhancements of cytotoxic effects of adriamycin (ADM) and vincristine (VCR) on PC-6 (lung cancer cell line) and Hattori (breast cancer cell line) were investigated by concomitant use of a calmodulin inhibitor: nicardipine, antiplatelet agents: oxyfedrine and trimethazidine and an antihypertensive agent: trichlormethiazide. Nicardipine increased the cytotoxic activity of both drugs but other agents did not produce any significant increase. Nicardipine increased the cytocidal effect of VCR on PC-6 about 2-fold and on Hattori about 3-fold. Furthermore, it also increased the effect of ADM on Hattori about 2-fold. Thus, nicardipine enhanced the cytocidal activity of VCR more remarkably than that of ADM.