Anti-cancer activity of the ethylacetate fraction from Orostachys japonicus for modulation of the signaling pathway in HepG2 human hepatoma cells

The molecular mechanisms of the ethylacetate (EtOAc) fraction from Orostachys japonicus (OJE) (including gallic acid, kaempferol, and quercetin) for anti-cancer activities in HepG2 cells were investigated. Apoptosis was detected using morphological observation of nuclear changes and investigation of phosphatidylserine exposure at the cytoplasmic membrane using FITC-Annexin V/PI staining. Activities of the apoptotic factors bcl-2, bax, cytochrome c, pro-caspase-3, 8, and 9, as well as MAPKs levels, were measured using western blotting. Some morphologic features of apoptosis were identified using confocal microscopy. OJE caused the expression of apoptotic proteins to change, as evidenced by an increased bax/bcl-2 ratio and increased expression of cytochrome c, and decreased expressions of pro-caspase-3, 8, and 9. After HepG2 cells were exposed to OJE, expressions of p-JNK and p-ERK1/2 increased in a dose dependent manner. OJE exhibits anti-cancer activity via apoptosis induction through a mitochondria dependent signaling pathway in HepG2 cells.