title: AZD6244 enhances the anti-tumor activity of sorafenib in ectopic and orthotopic models of human hepatocellular carcinoma (HCC).
abstract: OBJECTIVE
  Hepatocellular carcinoma (HCC) is a particularly vascularized solid tumor where the Raf/MEK/ERK pathway is activated; suggesting that inhibition of this pathway may have therapeutic potential.
  
  
  METHODS
  We treated patient-derived HCC xenografts with (i) sorafenib, (ii) AZD6244 (ARRY-142886), and (iii) sorafenib plus AZD6244. Western blotting was employed to determine pharmacodynamic changes in biomarkers relevant to both angiogenesis and MEK signaling. Apoptosis, microvessel density, and cell proliferation were analyzed by immunohistochemistry.
  
  
  RESULTS
  We report here that sorafenib treatment resulted in suppression of tumor growth, reduction in cell proliferation, induction of apoptosis and inhibition of mTOR targets. Sorafenib-induced elevation of the insulin-like growth factor receptor 1 (IGF-1R), phospho-c-Raf Ser338, phospho-MEK Ser217/221 and phospho-ERK Thr202/Tyr204 was attenuated by co-treating cells with anti-human IGF-1R antibody or over-expression of activated mutant p70S6K. Pharmacological inhibition of the MEK/ERK pathway by AZD6244 enhanced the anti-tumor effect of sorafenib in both orthotopic and ectopic models of HCC. Such inhibition led to a further increase in pro-apoptotic Bim, apoptosis and a profound inhibition of cell proliferation.
  
  
  CONCLUSIONS
  Our findings underscore the potential of a combined therapeutic approach with sorafenib and MEK inhibitors in the treatment of HCC.
authors.affiliation: Laboratory of Molecular Endocrinology, Division of Molecular and Cellular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre, 11 Hospital Drive, Singapore 169610, Singapore. cmrhth@nccs.com.sg
authors.forename: Hung
authors.initials: H
authors.lastname: Huynh
authors.forename: Van Chanh
authors.initials: VC
authors.lastname: Ngo
authors.forename: Heng Nung
authors.initials: HN
authors.lastname: Koong
authors.forename: Donald
authors.initials: D
authors.lastname: Poon
authors.forename: Su Pin
authors.initials: SP
authors.lastname: Choo
authors.forename: Han Chong
authors.initials: HC
authors.lastname: Toh
authors.forename: Choon Hua
authors.initials: CH
authors.lastname: Thng
authors.forename: Pierce
authors.initials: P
authors.lastname: Chow
authors.forename: Hock Soo
authors.initials: HS
authors.lastname: Ong
authors.forename: Alexander
authors.initials: A
authors.lastname: Chung
authors.forename: Boon Cher
authors.initials: BC
authors.lastname: Goh
authors.forename: Paul D
authors.initials: PD
authors.lastname: Smith
authors.forename: Khee Chee
authors.initials: KC
authors.lastname: Soo
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D001557:Benzenesulfonates / Q000494:pharmacology / Q000627:therapeutic use*; D001562:Benzimidazoles / Q000494:pharmacology / Q000627:therapeutic use*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004357:Drug Synergism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D016513:Mice, SCID; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D011725:Pyridines / Q000494:pharmacology / Q000627:therapeutic use*; D015398:Signal Transduction / Q000187:drug effects; D000077157:Sorafenib; D023041:Xenograft Model Antitumor Assays / Q000379:methods*; D048490:raf Kinases / Q000378:metabolism
chemical_list: C517975:AZD 6244; D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D001562:Benzimidazoles; D010671:Phenylurea Compounds; D011725:Pyridines; D009536:Niacinamide; D000077157:Sorafenib; D048490:raf Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases