Chemopreventive effects of gefitinib on nonsmoking-related lung tumorigenesis in activating epidermal growth factor receptor transgenic mice

Kadoaki Ohashi, Nagio Takigawa, Masahiro Osawa, Eiki Ichihara, Hiromasa Takeda, Toshio Kubo, Seiki Hirano, Tadashi Yoshino, Minoru Takata, Mitsune Tanimoto, Katsuyuki Kiura

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Twenty-five percent of all lung cancer cases are not attributable to smoking. Epidermal growth factor receptor (EGFR) mutations, which are involved in ∼50% of nonsmoker lung cancer, are positively correlated with responsiveness to gefitinib, and inversely correlated with smoking history. Activating EGFR mutations play a critical role in the carcinogenesis of nonsmoking-related lung cancer. To investigate the chemopreventive effects of gefitinib on nonsmoking-related lung cancer, we generated transgenic mice expressing EGFR L858R in type II pneumocytes constitutively using the surfactant protein-C promoter. The transgenic mice invariably developed atypical adenomatous hyperplasia at age 4 weeks and multifocal adenocarcinoma of varying sizes at age 7 weeks. Notably, the expression levels of phosphorylated and total ErbB2, ErbB3, and thyroid transcription factor-1 were elevated in the transgenic mice compared with wild-type controls at age 3 weeks. Administration of gefitinib to 3-week-old transgenic mice for 1 week before carcinogenesis reduced the amount of phosphorylated EGFR in the lungs of the mice to the baseline level. Gefitinib (5 mg/kg/d; n = 5, 5, and 15) or vehicle (n = 5, 5, and 15) was administered to transgenic mice from age 3 to 8, 13, and 18 weeks, respectively. The numbers of lung tumors in the control and gefitinib-treated groups were 1.75, 5.8, 10.2, and 0 (P < 0.05), respectively. No fatal toxic events occurred in either group, and gefitinib inhibited tumorigenesis completely in this mouse model. These results suggest the utility of molecular targeted chemoprevention against nonsmoking-related lung cancer.

Original languageEnglish
Pages (from-to)7088-7095
Number of pages8
JournalCancer Research
Volume69
Issue number17
DOIs
Publication statusPublished - Sep 1 2009

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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