Growth stimulation of hamster embryonic fibroblasts by phorbol esters

The growth on hamster embryonic fibroblasts was highly dependent on the serum concentration in the medium. A tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), enhanced the growth of hamster embryonic fibroblasts in the medium containing low concentrations of serum. Among phorbol derivatives, phorbol-12,13-didecanoate and 4-O-methyl-12-O-tetradecanoyl-phorbol-13-acetate also showed growth stimulation, but 4 alpha-phorbol-12,13-didecanoate, phorbol-12,13-diacetate and phorbol did not. TPA increased the accumulation of 2-deoxyglucose into the cells at low serum concentrations. Thus, hamster embryonic fibroblasts were sensitive to phorbol esters as growth stimulators, and TPA reduced the serum requirement of the cells.