title: Gefitinib prevents bleomycin-induced lung fibrosis in mice.
abstract: BACKGROUND
  Transforming growth factor-alpha and epidermal growth factor (EGF), the ligands for EGF receptor (EGFR), stimulate fibroblast proliferation and play an important role in the pathogenesis of pulmonary fibrosis. Therefore, inhibition of the EGFR signal by an EGFR tyrosine kinase inhibitor (EGFR-TKI) may prevent pulmonary fibrosis. However, there is a possibility that blocking the EGFR signal may inhibit epithelial cell repair, thereby exaggerating lung fibrosis.
  
  
  OBJECTIVE
  To investigate the effect of EGFR-TK inhibition on lung fibrosis.
  
  
  METHODS
  We looked at the effects of the EGFR-TKIs gefitinib (20, 90, 200 mg/kg) and AG1478 (12 mg/kg) on a bleomycin-induced lung fibrosis model in mice.
  
  
  RESULTS
  Gefitinib prevented lung fibrosis at all three doses. Furthermore, in those mice that did not receive bleomycin treatment, gefitinib at 200 mg/kg did not induce lung fibrosis. Immunohistochemistry revealed that phosphorylation of EGFR in lung mesenchymal cells induced by bleomycin was inhibited by gefitinib. AG1478 also attenuated the lung fibrosis. In vitro studies further demonstrated that the addition of gefitinib or AG1478 suppressed the EGFR ligand-induced proliferation of lung fibroblasts.
  
  
  CONCLUSIONS
  These findings suggest that, in the preclinical setting, EGFR-TKIs may have a protective effect on lung fibrosis induced by bleomycin. Because these molecular targeted drugs may have differing effects depending on species and individuals, a cautious interpretation is warranted.
authors.affiliation: Department of Pulmonary Medicine and Clinical Immunology, Dokkyo Medical University School of Medicine, 800 Kitakobayashi, Mibu, Tochigi 321-0293, Japan. ishiiysk@dokkyomed.ac.jp
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Ishii
authors.forename: Sakae
authors.initials: S
authors.lastname: Fujimoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fukuda
mesh_terms: D000818:Animals; D001761:Bleomycin; D018929:Cell Culture Techniques; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D000077156:Gefitinib; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000517:prevention & control*; D011799:Quinazolines / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D020032:Tyrphostins / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D020032:Tyrphostins; D001761:Bleomycin; C101044:RTKI cpd; D000077156:Gefitinib