title: Higher levels of c-Met expression and phosphorylation identify cell lines with increased sensitivity to AMG-458, a novel selective c-Met inhibitor with radiosensitizing effects.
abstract: OBJECTIVE
  c-Met is overexpressed in some non-small cell lung cancer (NSCLC) cell lines and tissues. Cell lines with higher levels of c-Met expression and phosphorylation depend on this receptor for survival. We studied the effects of AMG-458 on 2 NSCLC cell lines.
  
  
  METHODS
  3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assays assessed the sensitivities of the cells to AMG-458. Clonogenic survival assays illustrated the radiosensitizing effects of AMG-458. Western blot for cleaved caspase 3 measured apoptosis. Immunoblotting for c-Met, phospho-Met (p-Met), Akt/p-Akt, and Erk/p-Erk was performed to observe downstream signaling.
  
  
  RESULTS
  AMG-458 enhanced radiosensitivity in H441 but not in A549. H441 showed constitutive phosphorylation of c-Met. A549 expressed low levels of c-Met, which were phosphorylated only in the presence of exogenous hepatocyte growth factor. The combination of radiation therapy and AMG-458 treatment was found to synergistically increase apoptosis in the H441 cell line but not in A549. Radiation therapy, AMG-458, and combination treatment were found to reduce p-Akt and p-Erk levels in H441 but not in A549. H441 became less sensitive to AMG-458 after small interfering RNA knockdown of c-Met; there was no change in A549. After overexpression of c-Met, A549 became more sensitive, while H441 became less sensitive to AMG-458.
  
  
  CONCLUSIONS
  AMG-458 was more effective in cells that expressed higher levels of c-Met/p-Met, suggesting that higher levels of c-Met and p-Met in NSCLC tissue may classify a subset of tumors that are more sensitive to molecular therapies against this receptor.
authors: Department of Radiation Oncology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors: Bo
authors: B
authors: Li
authors: Artour
authors: A
authors: Torossian
authors: Yunguang
authors: Y
authors: Sun
authors: Ruihong
authors: R
authors: Du
authors: Adam P
authors: AP
authors: Dicker
authors: Bo
authors: B
authors: Lu
mesh_terms: D000631:Aminopyridines / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D045744:Cell Line, Tumor / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010766:Phosphorylation; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology*; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
chemical_list: C530596:1-(2-hydroxy-2-methylpropyl)-N-(5-(7-methoxyquinolin-4-yloxy)pyridin-2-yl)-5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxamide; D000631:Aminopyridines; D009363:Neoplasm Proteins; D011720:Pyrazoles; D011838:Radiation-Sensitizing Agents; D019859:Proto-Oncogene Proteins c-met