Cationic liposomes induce macrophage apoptosis through mitochondrial pathway

To clarify the mechanism of apoptosis of the macrophage-like cell line RAW2 64.7 induced by cationic liposomes, we focused on the mitochondria and inve stigated the changes in mitochondrial membrane potential and the release of cytochrome c following treatment of cationic liposomes composed of stearyl amine (SA-liposomes). SA-liposomes induced mitochondrial membrane depolariz ation and also the release of cytochrome c from mitochondria. Caspase-3 was also activated by SA-liposome treatment. Pretreatment of cells with N-acet ylcysteine, a scavenger of reactive oxygen species (ROS), conferred resista nce to the induction of the membrane depolarization, cytochrome c release, and caspase-3 activation by SA-liposomes. These results indicated that SA-l iposomes caused the apoptosis in RAW264.7 cells through the mitochondrial p athway, and ROS generation was required for this phenomenon. (C) 2001 Acade mic Press.