title: Preclinical evaluation of combined TKI-258 and RAD001 in hepatocellular carcinoma.
abstract: OBJECTIVE
  RAD001 targets at the mammalian target of rapamycin (mTOR), while TKI-258 is a potent tyrosine kinase inhibitor targeting at fibroblast growth factor receptor, vascular endothelial growth factor receptor, platelet-derived growth factor receptor and c-kit. We aim to study the activity of combined RAD001 and TKI-258 in cell lines and xenograft model of hepatocellular carcinoma (HCC), with reference to the parallel and upstream pathways of Akt-mTOR axis.
  
  
  METHODS
  A panel of 4 human HCC cell lines HepG2, Hep3B, PLC/PRF/5 and Huh7 and the Hep3B-derived xenograft were treated with TKI-258 or/and RAD001, respectively. Related mechanistic studies (including apoptosis and angiogenesis) were conducted.
  
  
  RESULTS
  There was an enhanced increase in suppression of cell proliferation with combined TKI-258 and RAD001 compared with either drug alone. The combination could significantly suppress the phosphorylation of mTOR, MEK1/2 and p38 MAPK. Although the addition of the TKI258 only slightly suppressed the phosphorylation of AKT induced by RAD001, the pi-mTOR and its downstream signaling pathways including pi-p70S6K, pi-S6 and pi-4EBP1 were lowered in the combination. In Hep3B-derived xenograft, TKI-258 and RAD001 had shown an enhanced inhibition of tumor growth without impact on the weight of animals. There was a reduction in microvessel density in the xenograft with the combination, which indicated an enhanced inhibition on angiogenesis. Pro-caspases-3 and PARP cleavage were slightly detected at 48 h after treatment, suggesting that the combination mainly increased the cytostatic arrest ability.
  
  
  CONCLUSIONS
  The combination of RAD001 and TKI-258 was active in HCC via inhibition of both mTOR-mediated signaling and its parallel pathways.
authors.affiliation: State Key Laboratory in Oncology in South China, Sir YK Pao Center for Cancer, Department of Clinical Oncology, Cancer Drug Testing Unit, Hong Kong Cancer Institute, Li Ka Shing Institute of Health Sciences and Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Chan
authors.forename: Chi-Hang
authors.initials: CH
authors.lastname: Wong
authors.forename: Cecilia P Y
authors.initials: CP
authors.lastname: Lau
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
authors.forename: Connie W C
authors.initials: CW
authors.lastname: Hui
authors.forename: Vivian W Y
authors.initials: VW
authors.lastname: Lui
authors.forename: Brigette B Y
authors.initials: BB
authors.lastname: Ma
authors.forename: Anthony T C
authors.initials: AT
authors.lastname: Chan
authors.forename: Winnie
authors.initials: W
authors.lastname: Yeo
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D001562:Benzimidazoles / Q000008:administration & dosage; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000068338:Everolimus; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000473:pathology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors; D015363:Quinolones / Q000008:administration & dosage; D020123:Sirolimus / Q000008:administration & dosage / Q000031:analogs & derivatives; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D023041:Xenograft Model Antitumor Assays
chemical_list: C500007:4-amino-5-fluoro-3-(5-(4-methylpiperazin-1-yl)-1H-benzimidazol-2-yl)quinolin-2(1H)-one; D001562:Benzimidazoles; D015363:Quinolones; D000068338:Everolimus; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus