Actinodaphnine induces apoptosis through increased nitric oxide, reactive oxygen species and down-regulation of NF-κB signaling in human hepatoma Mahlavu cells

Actinodaphnine, extracted from Cinnamomum insularimontanum (Lauraceae), possesses cytotoxicity in some cancers, but the mechanism by which actinodaphnine induces apoptosis in human hepatoma cells remains poorly understood. In this study, we investigated the mechanisms of apoptosis induced by actinodaphnine in human hepatoma Mahlavu cells. Treatment with actinodaphnine dose-dependently induced apoptosis in Mahlavu cells that correlated with increased intracellular nitric oxide (NO) and reactive oxygen species (ROS), disruptive mitochondrial transmembrane potential (Delta Psi(m)), and activation of caspase 3/7. Our data also demonstrated that actinodaphnine down-regulated activity of nuclear factor kappa B (NF-kappa B). The apoptotic response to actinodaphnine was markedly decreased in Mahlavu cells pretreated with dexsamethasone, a NO inhibitor, N-acetylcysteine (NAC), an antioxidant, and Boc-Asp(OMe)-fmk, a broad caspases inhibitor. These results suggested that actinodaphnine-induced apoptosis is initially mediated through the NO and/or ROS increase and caspases-dependent pathway. In conclusion, our results indicate that an increase of ROS and/or NO is the initial essential event that results in the decrease of Delta Psi(m) and the activation of caspases that commits the cells to the apoptotic pathway in actinodaphnine-treated hepatoma Mahlavu cells. (c) 2005 Elsevier Ltd. All rights reserved.