The Effect of Nifedipine Alone or Combined with Cytotoxic Chemotherapy on the Mouse NC Carcinoma In‐vitro and In‐vivo

— Effects of the calcium antagonist nifedipine on the response of the murine NC carcinoma has been examined alone and together with cytotoxic chemotherapy in-vitro and in-vivo. The cytotoxic drug combination of methotrexate and melphalan, or nifedipine alone (0·2–25 μg mL−1), caused a concentration-related reduction of NC cell growth in culture. At the lower concentrations, combination of the cytotoxic drugs with nifedipine resulted in an addition of the separate drug effects, but with drug concentrations that on their own approached maximal effectiveness the combined response was less than additive. NC tumours were excised from mice 14 days after inoculation s.c. with NC cells, weighed, and extracted for prostanoids. Mouse survival was determined up to day 121, and cancer spread was recorded postmortem. Nifedipine 1, 5 or 10 mg kg−1 had little or no effect on the tumour weight, tumour prostanoid content, metastasis to the lymph nodes or lungs, or on the increase of mouse longevity by the cytotoxic drugs.