C-Src activation mediates erlotinib resistance in head and neck cancer by stimulating c-Met

Laura P. Stabile, Guoqing He, Vivian Wai Yan Lui, Cassandra Henry, Christopher T. Gubish, Sonali Joyce, Kelly M. Quesnelle, Jill M. Siegfried, Jennifer R. Grandis

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

Purpose: Strategies to inhibit the EGF receptor (EGFR) using the tyrosine kinase inhibitor erlotinib have been associated with limited clinical efficacy in head and neck squamous cell carcinoma (HNSCC). Co-activation of alternative kinases may contribute to erlotinib resistance. Experimental Design: We generated HNSCC cells expressing dominant-active c-Src (DA-Src) to determine the contribution of c-Src activation to erlotinib response. Results: Expression of DA-Src conferred resistance to erlotinib in vitro and in vivo compared with vectortransfected control cells. Phospho-Met was strongly upregulated by DA-Src, and DA-Src cells did not produce hepatocyte growth factor (HGF). Knockdown of c-Met enhanced sensitivity to erlotinib in DA-Src cells in vitro, as did combining a c-Met or c-Src inhibitor with erlotinib. Inhibiting EGFR resulted in minimal reduction of phospho-Met in DA-Src cells, whereas complete phospho-Met inhibition was achieved by inhibiting c-Src. A c-Met inhibitor significantly sensitized DA-Src tumors to erlotinib in vivo, resulting in reduced Ki67 labeling and increased apoptosis. In parental cells, knockdown of endogenous c-Src enhanced sensitivity to erlotinib, whereas treatment with HGF to directly induce phospho-Met resulted in erlotinib resistance. The level of endogenous phospho-c-Src inHNSCCcell lines was also significantly correlated with erlotinib resistance. Conclusions: Ligand-independent activation of c-Met contributes specifically to erlotinib resistance, not cetuximab resistance, in HNSCC with activated c-Src, where c-Met activation is more dependent on c-Src than on EGFR, providing an alternate survival pathway. Addition of a c-Met or c-Src inhibitor to erlotinib may increase efficacy of EGFR inhibition in patients with activated c-Src.

Original languageEnglish (US)
Pages (from-to)380-392
Number of pages13
JournalClinical Cancer Research
Volume19
Issue number2
DOIs
StatePublished - Jan 15 2013
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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