Discordance between the effect of modulators of calcium on staurosporine-induced apoptosis and staurosporine-induced actin degradation.

Staurosporine produced DNA fragmentation characteristic of apoptosis and a dramatic alteration of cell structure that include alterations of cytoskeletal actin and cytoplasmic condensation with vacuolization. These changes were not induced by chelerythrine, a more specific PKC inhibitor than staurosporine. The calcium chelator, BAPTA, significantly reduced staurosporine-induced DNA fragmentation but did not affect staurosporine-induced changes in cytoskeletal actin. These data suggest that DNA fragmentation and actin degradation in apoptosis, induced by staurosporine, are under different regulatory control by calcium.