Inhibition of dimethylsulfoxide-induced differentiation in Friend erythroleukemic cells by diacylglycerols and phospholipase C.

The effects of diacylglycerols and phospholipase C on dimethylsulfoxide (DMSO)-induced differentiation were investigated in Friend erythroleukemic cells (FELC). Greater than 80% of cells become benzidine-positive when incubated with 1.5% DMSO. The tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), inhibits DMSO-induced differentiation in FELC. Diacylglycerols were found to inhibit DMSO-induced differentiation dose responsively with the order of potency being 1-oleoyl-2-acetylglycerol (OAG) greater than dicaprylin greater than dilaurin greater than diolein. Phospholipase C which releases endogenous diacylglycerols from membrane phospholipids also inhibited DMSO-induced differentiation dose responsively. These results support the hypothesis that diacylglycerols can have effects similar to tumor promoters and suggest that protein kinase C may be a common mechanism for tumor promotion.