title: Paracrine receptor activation by microenvironment triggers bypass survival signals and ALK inhibitor resistance in EML4-ALK lung cancer cells.
abstract: OBJECTIVE
  Cancer cell microenvironments, including host cells, can critically affect cancer cell behaviors, including drug sensitivity. Although crizotinib, a dual tyrosine kinase inhibitor (TKI) of ALK and Met, shows dramatic effect against EML4-ALK lung cancer cells, these cells can acquire resistance to crizotinib by several mechanisms, including ALK amplification and gatekeeper mutation. We determined whether microenvironmental factors trigger ALK inhibitor resistance in EML4-ALK lung cancer cells.
  
  
  METHODS
  We tested the effects of ligands produced by endothelial cells and fibroblasts, and the cells themselves, on the susceptibility of EML4-ALK lung cancer cell lines to crizotinib and TAE684, a selective ALK inhibitor active against cells with ALK amplification and gatekeeper mutations, both in vitro and in vivo.
  
  
  RESULTS
  EML4-ALK lung cancer cells were highly sensitive to ALK inhibitors. EGF receptor (EGFR) ligands, such as EGF, TGF-α, and HB-EGF, activated EGFR and triggered resistance to crizotinib and TAE684 by transducing bypass survival signaling through Erk1/2 and Akt. Hepatocyte growth factor (HGF) activated Met/Gab1 and triggered resistance to TAE684, but not crizotinib, which inhibits Met. Endothelial cells and fibroblasts, which produce the EGFR ligands and HGF, respectively, decreased the sensitivity of EML4-ALK lung cancer cells to crizotinib and TAE684, respectively. EGFR-TKIs resensitized these cells to crizotinib and Met-TKI to TAE684 even in the presence of EGFR ligands and HGF, respectively.
  
  
  CONCLUSIONS
  Paracrine receptor activation by ligands from the microenvironment may trigger resistance to ALK inhibitors in EML4-ALK lung cancer cells, suggesting that receptor ligands from microenvironment may be additional targets during treatment with ALK inhibitors.
authors.affiliation: Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa, Japan.
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Yamada
authors.forename: Shinji
authors.initials: S
authors.lastname: Takeuchi
authors.forename: Junya
authors.initials: J
authors.lastname: Nakade
authors.forename: Kenji
authors.initials: K
authors.lastname: Kita
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Shigeki
authors.initials: S
authors.lastname: Nanjo
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakamura
authors.forename: Kunio
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Manabu
authors.initials: M
authors.lastname: Soda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mano
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Uenaka
authors.forename: Seiji
authors.initials: S
authors.lastname: Yano
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000077548:Anaplastic Lymphoma Kinase; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018920:Coculture Techniques; D000077547:Crizotinib; D019008:Drug Resistance, Neoplasm; D042783:Endothelial Cells / Q000378:metabolism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D000069347:Erlotinib Hydrochloride; D005347:Fibroblasts / Q000378:metabolism; D005784:Gene Amplification; D017228:Hepatocyte Growth Factor / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology / Q000502:physiology; D008175:Lung Neoplasms; D008297:Male; D051379:Mice; D016513:Mice, SCID; D020125:Mutation, Missense; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D019899:Paracrine Communication; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D059016:Tumor Microenvironment; D023041:Xenograft Model Antitumor Assays
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; C522504:EML4-ALK fusion protein, human; C098587:GAB1 protein, human; C066855:HGF protein, human; D036341:Intercellular Signaling Peptides and Proteins; C516714:NVP-TAE684; D015514:Oncogene Proteins, Fusion; D011720:Pyrazoles; D011725:Pyridines; D011743:Pyrimidines; D011799:Quinazolines; D000077547:Crizotinib; D017228:Hepatocyte Growth Factor; D000069347:Erlotinib Hydrochloride; C000626173:ALK protein, human; C000626174:Alk protein, mouse; D000077548:Anaplastic Lymphoma Kinase; D066246:ErbB Receptors; C491743:MET protein, human; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases