Synergistic cytotoxicity of afatinib and cetuximab against EGFR T790M involves Rab11-dependent EGFR recycling

Zenta Watanuki, Hitomi Kosai, Nanae Osanai, Naoko Ogama, Mai Mochizuki, Keiichi Tamai, Kazunori Yamaguchi, Kennichi Satoh, Tatsuro Fukuhara, Makoto Maemondo, Masakazu Ichinose, Toshihiro Nukiwa, Nobuyuki Tanaka

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

EGFR is an important therapeutic target for non-small cell lung cancers (NSCLCs). Tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, are effective in cases with EGFR-activating mutations. However, most such cases become resistant through a secondary EGFR mutation, T790M. While the second-generation TKI afatinib has a higher affinity for double-mutant EGFRs, better efficacy is needed. Combining afatinib with the anti-EGFR monoclonal antibody cetuximab improves clinical outcomes, but the mechanism is unclear. Here we examined this effect using erythroleukemic K562 cells. The activating EGFR mutation L858R is sensitive to first-generation TKIs, and adding T790M confers resistance to these drugs. This double-mutant EGFR was moderately sensitive to afatinib, but responded weakly to cetuximab. Combined afatinib and cetuximab synergistically increased their cytotoxicity for K562 cells expressing the double-mutant EGFR. Apoptosis in these cells followed induction of the pro-apoptotic protein BIM. Unexpectedly, afatinib caused redistribution of EGFR to the cell surface through Rab11a-dependent recycling. Cetuximab reduced cell-surface EGFR, and total EGFR decreased synergistically when cetuximab was combined with afatinib. Our results suggest that the synergistic effect exerted by afatinib and cetuximab on NSCLCs is associated with BIM induction and alterations in EGFR status.

Original languageEnglish
Pages (from-to)269-276
Number of pages8
JournalBiochemical and biophysical research communications
Volume455
Issue number3-4
DOIs
Publication statusPublished - 2014 Dec 12

Keywords

  • Cytotoxicity
  • EGFR
  • EGFR-TKI

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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  • Cite this

    Watanuki, Z., Kosai, H., Osanai, N., Ogama, N., Mochizuki, M., Tamai, K., Yamaguchi, K., Satoh, K., Fukuhara, T., Maemondo, M., Ichinose, M., Nukiwa, T., & Tanaka, N. (2014). Synergistic cytotoxicity of afatinib and cetuximab against EGFR T790M involves Rab11-dependent EGFR recycling. Biochemical and biophysical research communications, 455(3-4), 269-276. https://doi.org/10.1016/j.bbrc.2014.11.003