title: AZD6244 (ARRY-142886) enhances the antitumor activity of rapamycin in mouse models of human hepatocellular carcinoma.
abstract: BACKGROUND
  The protein kinase B (AKT)/mammalian target of rapamycin (AKT/mTOR) and mitogen activated protein kinase/extracellular regulated kinase kinase/extracellular regulated kinase (MEK/ERK) signaling pathways have been shown to play an important role in hepatocellular carcinoma (HCC) growth and angiogenesis, suggesting that inhibition of these pathways may have therapeutic potential.
  
  
  METHODS
  We treated patient-derived HCC xenografts with 1) mTOR inhibitor rapamycin (RAPA); 2) MEK inhibitor AZD6244 (ARRY-142886); and 3) AZD6244 plus RAPA (AZD6244/RAPA). Western blotting was used to determine pharmacodynamic changes in biomarkers relevant to angiogenesis, mTOR pathway, and MEK signaling. Apoptosis, microvessel density, and cell proliferation were analyzed by immunohistochemistry.
  
  
  RESULTS
  We report here that pharmacological inhibition of the MEK/ERK pathway by AZD6244 enhanced the antitumor and antiangiogenic activities of mTOR inhibitor RAPA in both orthotopic and ectopic models of HCC. Such inhibition led to increased apoptosis, decreased angiogenesis and cell proliferation, reduced expression of positive cell cycle regulators, and increase in proapoptotic protein Bim.
  
  
  CONCLUSIONS
  Our findings indicate that the AZD6244/RAPA combination had antitumor and antiangiogenic effects in preclinical models of human HCC. Given the urgent need for effective therapies in HCC, clinical evaluating AZD6244/RAPA combination seems warranted.
authors.affiliation: Division of Molecular and Cellular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre, Singapore. cmrhth@nccs.com.sg
authors.forename: Hung
authors.initials: H
authors.lastname: Huynh
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001562:Benzimidazoles / Q000627:therapeutic use*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy*; D004357:Drug Synergism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors; D008114:Liver Neoplasms, Experimental / Q000188:drug therapy*; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D015398:Signal Transduction; D020123:Sirolimus / Q000627:therapeutic use*; D058570:TOR Serine-Threonine Kinases
chemical_list: C517975:AZD 6244; D000903:Antibiotics, Antineoplastic; D001562:Benzimidazoles; D047908:Intracellular Signaling Peptides and Proteins; C546842:MTOR protein, human; C546843:mTOR protein, mouse; D017346:Protein Serine-Threonine Kinases; D058570:TOR Serine-Threonine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020123:Sirolimus