Autophagy inhibition sensitizes KU-0063794-mediated anti-HepG2 hepatocellular carcinoma cell activity in vitro and in vivo.
Recent studies have indicated that mammalian target of rapamycin (mTOR) signaling has a critical role in the pathogenesis of hepatocellular carcinoma (HCC). In the current study, we investigated the activity of KU-0063794, a novel mTOR kinase inhibitor, against HepG2 HCC cells. Our results demonstrated that KU-0063794 blocked mTOR complex 1/2 (mTORC1/2) activation, and downregulated mTOR-regulated genes (Cyclin D1 and hypoxia-inducible factor 1α) in HepG2 cells. Consequently, KU-0063794 induced significant anti-survival and pro-apoptotic activities against HepG2 cells. When analyzing the possible KU-0063794-resistance factors, we showed that KU-0063794 induced cyto-protective autophagy activation in HepG2 cells, evidenced by GFP-light chain 3B (LC3B) puncta formation, p62 degradation, Beclin-1 expression and LC3B-I to LC3B-II conversion. Correspondingly, autophagy inhibitors, including bafliomycin A1, 3-methyladenine (3-MA) and chloroquine, dramatically enhanced KU-0063794-induced cytotoxicity against HepG2 cells. Further, RNAi knockdown of Beclin-1 also increased KU-0063794 sensitivity in HepG2 cells. In vivo, oral administration of KU-0063794 repressed HepG2 xenograft growth in severe combined immunodeficient (SCID) mice, and its activity was further enhanced with co-administration of the autophagy inhibitor 3-MA. In summary, KU-0063794 inhibits HepG2 cell growth in vitro and in vivo, its activity could be further enhanced with autophagy inhibition.
Department of Infectious Disease, Zhejiang Province People's Hospital, Hangzhou, China.
Tong
T
Yongxi
Department of Infectious Disease, Zhejiang Province People's Hospital, Hangzhou, China.
Huang
H
Haijun
Department of Interventional Radiology, Zhejiang Cancer Hospital, Hangzhou, China.
Zheng
Z
Jiaping
Department of Interventional Radiology, Zhejiang Cancer Hospital, Hangzhou, China.
Shao
S
Guoliang
Department of Infectious Disease, Zhejiang Province People's Hospital, Hangzhou, China. Electronic address: PANHongyingHZ@126.com.
Pan
P
Hongying
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D056945:Hep G2 Cells; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D009025:Morpholines / Q000008:administration & dosage*; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D011743:Pyrimidines / Q000008:administration & dosage*; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*
D009025:Morpholines; D011743:Pyrimidines; C541932:Ku 0063794; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases
Autophagy; Hepatocellular carcinoma; KU-0063794; Sensitization; mTOR