title: Antitumour efficacy of MEK inhibitors in human lung cancer cells and their derivatives with acquired resistance to different tyrosine kinase inhibitors.
abstract: BACKGROUND
  To study the molecular mechanisms regulating cancer cell resistance to four different tyrosine kinase inhibitors (TKIs): erlotinib, gefitinib, vandetanib and sorafenib.
  
  
  METHODS
  An in vitro model of acquired resistance to these TKIs was developed by continuously treating the human lung adenocarcinoma cell line CALU-3 with escalating doses of each drug. Transcriptional profiling was performed with Agilent whole genome microarrays. Western blot analysis, enzyme-linked immunosorbent (ELISA), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell proliferation, migration, invasion and anchorage-independent colony growth assays were conducted in vitro and experiments with established xenografts in athymic nude mice were performed in vivo in parental (P) and TKI-resistant (R) CALU-3 cell lines.
  
  
  RESULTS
  As compared with P-CALU-3 cells, in TKI-R CALU-3 cell lines a significant increase in the expression of activated, phosphorylated MET, IGF-1R, AKT, MEK, MAPK and of survivin was observed. Downregulation of E-cadherin and amphiregulin mRNAs and upregulation of vimentin, VE-cadherin, HIF-1α and vascular endothelial growth factor receptor-1 mRNAs were observed in all four TKI-R CALU-3 cell lines. All four TKI-R CALU-3 cells showed increased invasion, migration and anchorage-independent growth. Together, these data suggest epithelial to mesenchymal transition (EMT) in TKI-R CALU-3 cells. Treatment with several agents that target AKT, MET or IGF-1R did not affect TKI-R CALU-3 cell proliferation. In contrast, treatment with MSC19363669B and selumetinib, two selective MEK inhibitors, caused inhibition of cell proliferation, invasion, migration, anchorage-independent growth in vitro and of tumour growth in vivo of all four TKI-R CALU-3 cell lines.
  
  
  CONCLUSIONS
  These data suggest that resistance to four different TKIs is characterised by EMT, which is MEK-inhibitor sensitive in human CALU-3 lung adenocarcinoma.
authors.affiliation: Sezioni di Oncologia Medica, Seconda Università degli Studi di Napoli, Via S. Pansini 5, Naples 80131, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Morgillo
authors.forename: T
authors.initials: T
authors.lastname: Cascone
authors.forename: E
authors.initials: E
authors.lastname: D'Aiuto
authors.forename: E
authors.initials: E
authors.lastname: Martinelli
authors.forename: T
authors.initials: T
authors.lastname: Troiani
authors.forename: P
authors.initials: P
authors.lastname: Saintigny
authors.forename: R
authors.initials: R
authors.lastname: De Palma
authors.forename: J V
authors.initials: JV
authors.lastname: Heymach
authors.forename: L
authors.initials: L
authors.lastname: Berrino
authors.forename: C
authors.initials: C
authors.lastname: Tuccillo
authors.forename: F
authors.initials: F
authors.lastname: Ciardiello
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy*; D000077192:Adenocarcinoma of Lung; D000818:Animals; D001557:Benzenesulfonates / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D000069347:Erlotinib Hydrochloride; D000077156:Gefitinib; D020869:Gene Expression Profiling; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors*; D051379:Mice; D008819:Mice, Nude; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D010880:Piperidines / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D011725:Pyridines / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D000077157:Sorafenib; D023041:Xenograft Model Antitumor Assays
chemical_list: D001557:Benzenesulfonates; D010671:Phenylurea Compounds; D010880:Piperidines; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D011799:Quinazolines; D009536:Niacinamide; D000077157:Sorafenib; D000069347:Erlotinib Hydrochloride; D020930:MAP Kinase Kinase Kinases; D000077156:Gefitinib; C452423:vandetanib