Roles of protein kinase C δ in the accumulation of P53 and the induction of apoptosis in H2O2-treated bovine endothelial cells

To clarify the signaling pathways of oxidative stress-induced apoptosis in bovine aortic endothelial cells (BAEC), we treated cells with 1 mM H2O2 and investigated the roles of protein kinase C delta (PKCdelta) and Ca2+ in the accumulation of p53 associated with apoptosis. The treatment of cells with H2O2 caused the accumulation of p53, which was inhibited by rottlerin (a PKCdelta inhibitor) but not by BAPTA-AM (an intracellular Ca2+ chelator). PKCdelta itself was activated through the phosphorylation at tyrosine residues. H2O2 induced the release of cytochrome c and the activation of caspases 3 and 9, and these apoptotic signals were inhibited by rottlerin and BAPTA-AM. These results suggest that PKCdelta contributes to the accumulation of p53 and that Ca2+ plays a role in downstream signals of p53 leading to apoptosis in H2O2-treated BAEC.