Actinodaphnine induces apoptosis through increased nitric oxide, reactive oxygen species and down-regulation of NF-kappaB 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 (DeltaPsi(m)), and activation of caspase 3/7. Our data also demonstrated that actinodaphnine down-regulated activity of nuclear factor kappaB (NF-kappaB). 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 DeltaPsi(m) and the activation of caspases that commits the cells to the apoptotic pathway in actinodaphnine-treated hepatoma Mahlavu cells.

Annoglabayin, a novel dimeric kaurane diterpenoid, and apoptosis in Hep G2 cells of annomontacin from the fruits of Annona glabra.

Annoglabayin (1), a novel Annona dimeric kaurane diterpenoid, has been isolated from Annona glabra, and its structure was determined on the basis of spectroscopic analysis. Annoglabayin (1) contains a unique carbon bridge between two nor-ent-kaurane monomeric units. The dose-response of 2 in Hep G2 cells indicated that 2 increased DNA damage. In addition, our results showed that 2 induced a noticeable decrease in mitochondrial transmembrane potential during treatment. These results indicate that 2 produces apoptotic events in Hep G2 cells, through inducing changes in mitochondria.

Involvement of reactive oxygen species, but not mitochondrial permeability transition in the apoptotic induction of human SK-Hep-1 hepatoma cells by shikonin.

Shikonin has been demonstrated to exhibit anti-cancer activity, but the underlying mechanisms are poorly understood. In this report, we showed that the administration of shikonin could result in the induction of apoptotic cell death of human hepatoma cell line, SK-Hep-1. As evident by the flow-cytometric studies, shikonin has the capability of generating increased amounts of intracellular reactive oxygen species (ROS) during the early stage of this apoptotic process (ca. one-hour), and subsequently accompanied by the dissipation of mitochondrial transmembrane potential (deltapsi (m)) at 3 hours. Further studies indicated that this apoptotic process could effectively be protected by the pretreatment of shikonin-treated cells with glutathione (GSH) and N-acetylcysteine (NAC), a precursor of GSH, but not by cyclosporin A (CyA), an inhibitor of mitochondrial permeability transition (MPT) pore. These data further proved that ROS-mediated oxidative stress was the pivotal element involved in the induction of apoptosis of SK-Hep-1 cells. Taken together, we suggest that shikonin-induced apoptosis of SK-Hep-1 cells proceeds by an oxidative stress-mediated pathway.