title: Polyphyllin VII Induces an Autophagic Cell Death by Activation of the JNK Pathway and Inhibition of PI3K/AKT/mTOR Pathway in HepG2 Cells.
abstract: Polyphyllin VII (PP7), a pennogenyl saponin isolated from Rhizoma Paridis, exhibited strong anticancer activities in various cancer types. Previous studies found that PP7 induced apoptotic cell death in human hepatoblastoma cancer (HepG2) cells. In the present study, we investigated whether PP7 could induce autophagy and its role in PP7-induced cell death, and elucidated its mechanisms. PP7 induced a robust autophagy in HepG2 cells as demonstrated by the conversion of LC3B-I to LC3B-II, degradation of P62, formation of punctate LC3-positive structures, and autophagic vacuoles tested by western blot analysis or InCell 2000 confocal microscope. Inhibition of autophagy by treating cells with autophagy inhibitor (chloroquine) abolished the cell death caused by PP7, indicating that PP7 induced an autophagic cell death in HepG2 cells. C-Jun N-terminal kinase (JNK) was activated after treatment with PP7 and pretreatment with SP600125, a JNK inhibitor, reversed PP7-induced autophagy and cell death, suggesting that JNK plays a critical role in autophagy caused by PP7. Furthermore, our study demonstrated that PP7 increased the phosphorylation of AMPK and Bcl-2, and inhibited the phosphorylation of PI3K, AKT and mTOR, suggesting their roles in the PP7-induced autophagy. This is the first report that PP7 induces an autophagic cell death in HepG2 cells via inhibition of PI3K/AKT/mTOR, and activation of JNK pathway, which induces phosphorylation of Bcl-2 and dissociation of Beclin-1 from Beclin-1/Bcl-2 complex, leading to induction of autophagy.
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Xuejing
authors.initials: X
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Jiaolin
authors.initials: J
authors.lastname: Bao
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Meiwan
authors.initials: M
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Jian-Bo
authors.initials: JB
authors.lastname: Wan
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Huanxing
authors.initials: H
authors.lastname: Su
authors.affiliation: College of Pharmacy, South Central University for Nationalities, Wuhan 430074, China.
authors.forename: Zhinan
authors.initials: Z
authors.lastname: Mei
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
authors.forename: Chengwei
authors.initials: C
authors.lastname: He
mesh_terms: D001343:Autophagy / Q000187:drug effects*; D004789:Enzyme Activation; D056945:Hep G2 Cells; D006801:Humans; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors*; D012503:Saponins / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors*
chemical_list: D000081082:Phosphoinositide-3 Kinase Inhibitors; D012503:Saponins; C585643:polyphyllin VII; C546842:MTOR protein, human; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D048670:MAP Kinase Kinase 4