Epidermal growth factor and tumor promoters prevent DNA fragmentation by different mechanisms.

Serum deprivation of C3H 10T 1/2 fibroblasts resulted in DNA fragmentation which was prevented by growth factors such as Epidermal Growth Factor or the tumor promoters, 12-0-tetradecanoyl-13-0-phorbol acetate and Dihydroteleocidin B. Palmityl carnitine, an inhibitor of Ca2+-phospholipid-dependent protein kinase C, reversed the effects of the tumor promoters, but not the effect of Epidermal Growth Factor.