Calcium-dependent Trichosanthin-induced Generation of Reactive Oxygen Species Invilved in Apoptosis of Human Choriocarcinoma Cells

摘要

The type-I ribosome-inactivating protein trichosanthin (TCS)has a broad spectrum of biological and pharmacological activities, including abortifacient, anti-tumor and anti-HIV. We found for the first time that TCS indeced production of reactive oxygen species (ROS)in JAR cells by using fluorescent probe 2',7'-dichlorofluorescin deacetate with confocal laser scanning microscopy. TCS-indeced ROS showed dependence on the increade in intracellular calcium and on the presence of extracellular calcium. The production of ROS increased rapidly after the application of TCS,which paralleled TCS-induced increase in intracellular calcium monitored using fluo 3-AM, suggesting that TCS-indeced ROS might mediate by the increase in intracellular Ca2~+ concentration. Simultaneous observation of the nuclear morphological changes and production of ROS in JAR cells with two-photon laser scanning microscopy and confocal laser scanning microscopy revealed that ROS involved in the apoptosis of JAR cells, which was confirmed by that antioxidant α-tocopherol prevented TCS-induced ROS formation and cell death. The finding that calcium-dependent TCS-induced ROS involved in the apoptosis of JAR cells might provide new insight into the anti-tumor and anti-HIV mechanism of TCS.