Cordycepin is the main functional component of Cordyceps militaris, which has been widely used in
oriental traditional medicine. This compound has been shown to possess many pharmacological properties, such as enhancing the body's immune function, and anti-inflammatory, anti-aging and anticancer effects. In the present study, we investigated the apoptotic effects of
cordycepin in human prostate
carcinoma cells. We found that treatment with
cordycepin significantly inhibited cell growth by inducing apoptosis in PC-3 cells. Apoptosis induction of PC-3 cells by
cordycepin showed correlation with proteolytic activation of
caspase-3 and -9, but not
caspase-8, and concomitant degradation of
poly (ADP-ribose) polymerases, collapse of the mitochondrial membrane potential (
MMP). In addition,
cordycepin treatment resulted in an increase of the Bax/Bcl-2 (or Bcl-xL) ratio, downregulation of
inhibitor of apoptosis protein (IAP) family members, Bax conformational changes, and release of
cytochrome c from the mitochondria to the cytosol. The
cordycepin-induced apoptosis was also associated with the generation of intracellular
reactive oxygen species (ROS). However, the quenching of ROS generation with
antioxidant N-acetyl-L-cysteine conferred significant protection against
cordycepin-elicited ROS generation, disruption of the
MMP, modulation of Bcl-2 and IAP family
proteins,
caspase-3 and -9 activation and apoptosis. This indicates that the cellular ROS generation plays a pivotal role in the initiation of
cordycepin-triggered apoptotic death. Collectively, our findings suggest that
cordycepin is a potent inducer of apoptosis of
prostate cancer cells via a mitochondrial-mediated intrinsic pathway and that this agent may be of value in the development of a potential therapeutic candidate for both the prevention and treatment of
cancer.