Transcription-dependent epidermal growth factor receptor activation by hepatocyte growth factor

Thomas E. Reznik, Yingying Sang, Yongxian Ma, Roger Abounader, Eliot M. Rosen, Shuli Xia, John Laterra

Research output: Contribution to journalArticlepeer-review

Abstract

The mechanisms and biological implications of coordinated receptor tyrosine kinase coactivation remain poorly appreciated. Epidermal growth factor receptor (EGFR) and c-Met are frequently coexpressed in cancers, including those associated with hepatocyte growth factor (HGF) overexpression, such as malignant astrocytoma. In a previous analysis of the HGF-induced transcriptome, we found that two EGFR agonists, transforming growth factor-α and heparin-binding epidermal growth factor-like growth factor (HB-EGF), are prominently up-regulated by HGF in human glioma cells. We now report that stimulating human glioblastoma cells with recombinant HGF induces biologically relevant EGFR activation. EGFR phosphorylation at Tyr845 and Tyr1068 increased 6 to 24h after cell stimulation with HGF and temporally coincided with the induction of transforming growth factor-α (∼5-fold) and HB-EGF (∼23-fold) expression. Tyr845 and Tyr1068 phosphorylation, in response to HGF, was inhibited by cycloheximide and actinomycin D, consistent with a requirement for DNA transcription and RNA translation. Specifically, blocking HB-EGF binding to EGFR with the antagonist CRM197 inhibited HGF-induced EGFR phosphorylation by 60% to 80% and inhibited HGF-induced S-G2-M transition. CRM197 also inhibited HGF-induced anchorage-dependent cell proliferation but had no effect on HGF-mediated cytoprotection. These findings establish that EGFR can be activated with functional consequences by HGF as a result of EGFR ligand expression. This transcription-dependent cross-talk between the HGF receptor c-Met and EGFR expands our understanding of receptor tyrosine kinase signaling networks and may have considerable consequences for oncogenic mechanisms and cancer therapeutics.

Original languageEnglish (US)
Pages (from-to)139-150
Number of pages12
JournalMolecular Cancer Research
Volume6
Issue number1
DOIs
StatePublished - Jan 1 2008

ASJC Scopus subject areas

  • Molecular Biology
  • Oncology
  • Cancer Research

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