Lipoxygenase may be involved in cationic liposome-induced macrophage apoptosis

The purpose of this study was to determine the source of reactive oxygen sp ecies (ROS) generation and the contribution of ROS to the apoptosis of RAW2 64.7 cells induced by cationic liposomes. Cationic liposome-induced apoptos is was inhibited by lipoxygenase inhibitors, but not inhibitors of NADPH-ox idase, xanthine oxidase or cyclooxygenase. ROS generation induced by cation ic liposomes was also inhibited by the lipoxygenase inhibitor NDGA. Further more, lipid peroxidation was observed following liposome treatment, but the apoptosis was not inhibited by the antioxidant alpha -tocopherol. These fi ndings suggested that lipoxygenase is responsible for ROS generation, and R OS but not lipid peroxidation acts as a key mediator in the progress of apo ptosis induced by cationic liposomes. (C) 2001 Academic Press.