두경부편편상피세포암주에 대한 자작나무껍질 유래 Betulin의 항암효과

Abstract

Betulin is a naturally occuring lupane-type pentacyclic triterpenoid, producing various pharmacological activities such as anti-viral, anti-bacterial, and anti-cancer effects. The principal purpose of this study is to characterize the apoptotic effect of betulin, derived from the outer bark of birch, on head and neck squamous cell carcinoma at a molecular level. Betulin decreased cell viability in a concentration-dependent manner. From the flow cytometry experiments, it was revealed that betulin expressed apoptotic cell death rather than necrosis. To elucidate the apoptotic pathway, several apoptosis-related protein factors were detected with western blotting method. Pro-apoptotic protein (Bax) and anti-apoptotic protein (Bcl-2) in the mitochondrial pathway was unchanged in control and betulin-treated groups. Caspase-3, one of the effector caspases, was found to have almost the same protein levels in all groups. In contrast, caspase-7 and PARP expressions decreased with increasing betulin concentration. Cleaved PARP level increased as the betulin concentration increased. These findings imply that betulin presents apoptotic effect on FaDu cell through calcium mediated calpain/caspase-7/PARP pathway