Inhibition by dihydropyridine class calcium channel blockers of tumor cell-platelet-endothelial cell interactions in vitro and metastasis in vivo.

Three calcium channel blockers of the dihydropyridine class were tested in vitro for their effects on tumor cell-platelet-endothelial cell interactions and in vivo for antimetastatic properties. Felodipine, nimodipine and nifedipine inhibited tumor cell-induced platelet aggregation in vitro in a dose-dependent manner. These compounds also inhibited platelet-enhanced tumor cell adhesion to endothelial cells in vitro. Lung colony formation ("experimental" metastasis) and spontaneous pulmonary metastasis were inhibited by felodipine, nimodipine and nifedipine. From the present studies on three calcium channel blockers of the dihydropyridine class we hypothesize that calcium channel blockers may represent a new generic class of antimetastatic agents.