Involvement of protein kinase Cdelta in induction of apoptosis by cationic liposomes in macrophage-like RAW264.7 cells

Abstract

We have recently demonstrated that reactive oxygen species (ROS) play an important role in RAW264.7 cell apoptosis induced by cationic liposomes composed of stearylamine (SA-liposomes). In this study, we investigated whether protein kinase Cdelta PKCdelta) is involved in apoptosis induced by cationic liposomes. Tyrosine phosphorylation, nuclear localization, and cleavage of PKCdelta were observed following the treatment of cells with SA-liposomes, suggesting that SA-liposomes activate PKCdelta. Rottlerin, a specific inhibitor of PKCdelta, inhibited ROS generation and also suppressed apoptosis. Cell surface proteoglycans may contribute to PKCdelta activation by SA-liposomes. These findings suggest that PKCdelta is strongly associated with apoptosis induced by SA-liposomes.