Cordycepin, an active ingredient of the insect fungus Cordyceps spp., shows strong antioxidant and anticancer activities. Several molecular mechanisms have been attributed to its
inhibitory effects on a wide range of tumor cells; however, the mechanism causing cancer
cell death is still obscure. For the current study, we further investigated the mechanism
responsible for targeting cordycepin-induced cell death and its association with autophagy
in human prostate carcinoma LNCaP cells. Our results show that cordycepin resulted in
significant reduction in LNCaP cell survival by inducing apoptotic cell death. Cordycepin
treatment caused a dose-dependent increase of pro-apoptotic Bax and decrease of antiapoptotic Bcl-2, triggering collapse of the mitochondrial membrane potential and activation
of caspase-9 and -3. Cordycepin-induced cell death was also associated with induction
of Fas and death receptor 5, activation of caspase-8, and truncation of Bid (tBid), suggesting that tBid might serve to connect activation of both the mitochondrial-mediated
intrinsic and death receptor-mediated extrinsic apoptotic pathways. The general caspase
inhibitor, z-VAD-fmk, completely abolished cordycepin-induced cell death, demonstrating