Lung cancers with acquired resistance to EGFR inhibitors occasionally harbor BRAF gene mutations but lack mutations in KRAS, NRAS, or MEK1

Kadoaki Ohashi, Lecia V. Sequist, Maria E. Arcila, Teresa Moran, Juliann Chmielecki, Ya Lun Lin, Yumei Pan, Lu Wang, Elisa De Stanchina, Kazuhiko Shien, Keisuke Aoe, Shinichi Toyooka, Katsuyuki Kiura, Lynnette Fernandez-Cuesta, Panos Fidias, James Chih Hsin Yang, Vincent A. Miller, Gregory J. Riely, Mark G. Kris, Jeffrey A. EngelmanCindy L. Vnencak-Jones, Dora Dias-Santagata, Marc Ladanyi, William Pao

Research output: Contribution to journalArticle

324 Citations (Scopus)

Abstract

Acquired resistance to EGF receptor (EGFR) tyrosine kinase inhibitors (TKIs) is inevitable in metastatic EGFR-mutant lung cancers. Here, we modeled disease progression using EGFR-mutant human tumor cell lines. Although five of six models displayed alterations already found in humans, one harbored an unexpected secondary NRAS Q61K mutation; resistant cells were sensitive to concurrent EGFR and MEK inhibition but to neither alone. Prompted by this finding and because RAS/RAF/MEK mutations are known mediators of acquired resistance in other solid tumors (colon cancers, gastrointestinal stromal tumors, and melanomas) responsive to targeted therapies, we analyzed the frequency of secondary KRAS/NRAS/BRAF/MEK1 gene mutations in the largest collection to date of lung cancers with acquired resistance to EGFR TKIs. No recurrent NRAS, KRAS, or MEK1 mutations were found in 212, 195, or 146 patient samples, respectively, but 2 of 195 (1%) were found to have mutations in BRAF (G469A and V600E). Ectopic expression of mutant NRAS or BRAF in drug-sensitive EGFR-mutant cells conferred resistance to EGFR TKIs that was overcome by addition of a MEK inhibitor. Collectively, these positive and negative results provide deeper insight into mechanisms of acquired resistance to EGFR TKIs in lung cancer and inform ongoing clinical trials designed to overcome resistance. In the context of emerging knowledge about mechanisms of acquired resistance to targeted therapies in various cancers, our data highlight the notion that, even though solid tumors share common signaling cascades, mediators of acquired resistance must be elucidated for each disease separately in the context of treatment.

Original languageEnglish
Pages (from-to)E2127-E2133
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number31
DOIs
Publication statusPublished - Jul 31 2012

Keywords

  • Erlotinib
  • Gefitinib
  • Nras mutation

ASJC Scopus subject areas

  • General

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    Ohashi, K., Sequist, L. V., Arcila, M. E., Moran, T., Chmielecki, J., Lin, Y. L., Pan, Y., Wang, L., De Stanchina, E., Shien, K., Aoe, K., Toyooka, S., Kiura, K., Fernandez-Cuesta, L., Fidias, P., Yang, J. C. H., Miller, V. A., Riely, G. J., Kris, M. G., ... Pao, W. (2012). Lung cancers with acquired resistance to EGFR inhibitors occasionally harbor BRAF gene mutations but lack mutations in KRAS, NRAS, or MEK1. Proceedings of the National Academy of Sciences of the United States of America, 109(31), E2127-E2133. https://doi.org/10.1073/pnas.1203530109