Caspase-8 is in the death receptor pathway whereas caspase-9 is in the mitochondrial pathway, and both pathways share caspase-3 [30]. Treatment with EGCG conjugated with capric acid increases the formation of reactive oxygen species (ROS), loss of mitochondrial membrane potential (MMP), AZD0530 mw release of cytochrome c, activation of caspase-9 and activation of caspase-3. In addition, EGCG conjugated with capric acid also activates the extrinsic pathway as demonstrated by the time-dependent increase in Fas

expression and caspase-8 activity [24]. Two distinct downstream pathways have been identified for activation of apoptosis after caspase-8 is activated. In one pathway, caspase-8 directly processes downstream effector caspase-3, -6, and -7. In an alternative pathway, caspase-8 activates crosstalk between the death receptor pathway and the mitochondrial pathway by the cleavage of Bid to Bid, a pro-apoptotic member of the

Ganetespib cell line Bcl2 family. The activation of caspase-8 has a central role in Fas-mediated apoptosis. Moreover, the cleavage of Bid has been shown to be associated with caspase-8 activation [31]. Taken together, the data presented in this study suggest that catechin-induced apoptosis is mediated by the death receptor and mitochondrial apoptotic pathways as demonstrated by increased expression levels of caspase-3, -8 and -9 after CH treatment. In addition, this study suggests that catechin activates the extrinsic death pathway as demonstrated by increased expression levels of caspase-8. p53, the most commonly mutated gene associated with cancer [32], helps to regulate the cell cycle and has a key role in ensuring that damaged cells are destroyed by apoptosis. The data presented in this study indicate that the expression levels of p53 and caspase-3, Bortezomib -8 and -9 were markedly increased after CH treatment in a concentration-dependent manner. These data suggest that catechin induced apoptosis by regulating pro-apoptotic genes. The find more possibility that p53-mediated apoptosis may be associated with the activation of caspase-3, -8 and -9 is suggested by the ability of p53 to activate both the extrinsic and intrinsic apoptotic pathways [30, 33, 34]. p53 enhances cancer cell

apoptosis, and it prevents cell replication by stopping the cell cycle at G1 or interphase [35]. By inducing the release of mitochondrial cytochrome c, p53 might be able to activate effector caspases including caspase-3. Caspase-3, -8, and -9 may be the apoptotic effector machinery engaged by p53 to mediate teratogen-induced apoptotic pathways [36]. Conclusion In conclusion, to our knowledge, the results presented in this study show for the first time that CH exhibits anticancer effects by blocking the proliferation of MCF7 cells and inducing apoptosis in part by modulating expression levels of caspase-3, -8, and -9 and p53. The induction of apoptosis by CH is affected by its ability to regulate the expression of pro-apoptotic genes such as caspase-3, -8, and -9 and p53.