Stimulation of prostaglandin synthesis by tumor-promoting phorbol-12, 13-diesters in canine kidney (MDCK) cells. Cycloheximide inhibits the stimulated prostaglandin synthesis, deacylation of lipids, and morphological changes.

Tumor-promoting 12-O-tetradecanoyl-phorbol-13-acetate and phorbol-12, 13-di-decanoate, but not the non-tumor-promoting 4alpha-phorbol-12, 13-di-decanoate, stimulated deacylation of cellular lipids, prostaglandin biosynthesis, and morphological changes in cultured MDCK cells. The increased prostaglandin biosynthesis and morphological changes required at least 24 h for expression. Cycloheximide inhibited the stimulated prostaglandin biosynthesis, the changes in morphology, and the increased lipid deacylation, but hydrocortisone (1.0 microgram/ml) did not. Indomethacin (0.5 microgram/ml) completely inhibited the stimulated prostaglandin biosynthesis and also inhibited some deacylation of cellular lipids. Indomethacin, however, did not effect the 12-O-tetradecanoyl-phorbol-13-acetate-stimulated changes in morphology.