Hepatocellular carcinoma is a cancer of high mortality; therefore, the effective therapy on this cancer is an imperative issue. Recently, anticancer agent combined with natural products has been demonstrated to increase apoptosis of various cancer cells effectively. Accordingly, we investigated the apoptotic effect and possible mechanism of the ethanol extract from Taiwanofungus salmoneus (=Antrodia salmonea) mycelium (TsE) alone or in combination with cisplatin in SK-Hep-1 cells. In this study, the proliferation of SK-Hep-1 cells could be inhibited at various concentrations of TsE for 24 h whereas TsE combined with cisplatin would inhibit the cell proliferation more notably. Moreover, the DNA damage and the interruption of cell cycle of SK-Hep-1 cells would be effectively raised after incubation with TsE combined with cisplatin for 24 h. The apoptosis of cells was dramatically induced, and the expression of caspases 3, 8, and 9, apoptosis-related protein, were significantly upregulated. Therefore, we proposed that the TsE combined with cisplatin inhibited cell proliferation by elevating sub-G1 phase, inducing DNA damage, activating caspases 3, 8, and 9 activities, and triggering cells apoptosis. These results reveal that TsE could be a potential adjuvant chemotherapeutic agent.

In the current study, we examined the effects of the nonpsychoactive cannabinoid, cannabidiol, on the induction of apoptosis in leukemia cells. Exposure of leukemia cells to cannabidiol led to cannabinoid receptor 2 (CB2)-mediated reduction in cell viability and induction in apoptosis. Furthermore, cannabidiol treatment led to a significant decrease in tumor burden and an increase in apoptotic tumors in vivo. From a mechanistic standpoint, cannabidiol exposure resulted in activation of caspase-8, caspase-9, and caspase-3, cleavage of poly(ADP-ribose) polymerase, and a decrease in full-length Bid, suggesting possible cross-talk between the intrinsic and extrinsic apoptotic pathways. The role of the mitochondria was further suggested as exposure to cannabidiol led to loss of mitochondrial membrane potential and release of cytochrome c. It is noteworthy that cannabidiol exposure led to an increase in reactive oxygen species (ROS) production as well as an increase in the expression of the NAD(P)H oxidases Nox4 and p22(phox). Furthermore, cannabidiol-induced apoptosis and reactive oxygen species (ROS) levels could be blocked by treatment with the ROS scavengers or the NAD(P)H oxidase inhibitors. Finally, cannabidiol exposure led to a decrease in the levels of p-p38 mitogen-activated protein kinase, which could be blocked by treatment with a CB2-selective antagonist or ROS scavenger. Together, the results from this study reveal that cannabidiol, acting through CB2 and regulation of Nox4 and p22(phox) expression, may be a novel and highly selective treatment for leukemia.