Induction of apoptosis by ethanol extract of Evodia rutaecarpa in HeLa human cervical cancer cells via activation of AMP-activated protein kinase

The fruit of Evodia rutaecarpa (Juss.) Benth has been used widely in traditional medicine therapy. Although it has been shown to possess many pharmacological activities, the molecular mechanisms of its anti-cancer activity have not been clearly elucidated. In the present study, we investigated the pro-apoptotic effects of an ethanol extract isolated from immature fruits of E. rutaecarpa (EEER) in HeLa human cervical cancer cells. EEER treatment decreased the cell viability of HeLa cells in a concentration-dependent manner, which was related to apoptotic cell death resulting from apoptotic body formation, DNA fragmentation, and an increased population of annexin V+-positive cells. EEER treatment significantly suppressed anti-apoptotic Bcl-2 expression, leading to subsequent loss of mitochondrial membrane potential (MMP), while it did not change expression levels of death receptor (DR)-related proteins. EEER treatment increased activity of caspase-3 and-9 but not caspase-8, and pretreatment of a caspase-3 inhibitor markedly attenuated EEER-induced apoptosis. Furthermore, EEER activated the AMP-activated protein kinase (AMPK) signaling pathway; however, inhibition of AMPK markedly abrogated EEER-induced apoptosis. Overall, the results suggest that the apoptotic activity of EEER may be associated with a caspase-dependent cascade through activation of the intrinsic signaling pathway connected with AMPK activation. E. rutaecarpa could be a prospective clinical application to treat human cervical cancer.