Role of protein kinase C in the inhibition by fibroblast growth factor of apoptosis in serum-depleted endothelial cells.

Apoptosis in vascular endothelial cells is suppressed by fibroblast growth factor (FGF)1. In order to investigate the signal transduction system that regulates endothelial apoptosis, we studied the effects of several mitogenic factors. Apoptosis occurred in human vascular endothelial cells under serum-free conditions, and FGF inhibited apoptosis without a requirement of any cooperative factors, as distinct from the mitogenic response. Other mitogenic agents, such as epidermal growth factor, transferrin, transforming growth factor beta, and interleukin 1 etc., with the exception of dexamethasone, had no such inhibitory effects. The effect of FGF was mimicked by a phorbol ester and was prevented by an inhibitor of protein kinase C. The results suggest that the FGF and protein kinase C are important in endothelial apoptosis.