EGF receptor activates MET through MAPK to enhance non-small cell lung carcinoma invasion and brain metastasis

Cancer Res. 2013 Aug 15;73(16):5053-65. doi: 10.1158/0008-5472.CAN-12-3775. Epub 2013 Jun 21.

Abstract

MET amplification as a mechanism of acquired resistance to EGF receptor (EGFR)-targeted therapies in non-small cell lung carcinoma (NSCLC) led to investigation of novel combinations of EGFR and MET kinase inhibitors. However, promiscuous interactions between MET and ERBB family members have made it difficult to evaluate the effects of MET on EGFR signaling, both independent of drug treatment and in the context of drug resistance. We addressed this issue by establishing a 32D model cell system wherein ERBBs or MET are expressed alone and in combination. Using this model, we determined that EGFR signaling is sufficient to induce MET phosphorylation, although MET activation is enhanced by coexpression of ERBB3. EGFR-MET cross-talk was not direct, but occurred by a combined regulation of MET levels and intermediary signaling through mitogen-activated protein kinases (MAPK). In NSCLCs harboring either wild-type or mutant EGFR, inhibiting EGFR or MAPK reduced MET activation and protein levels. Furthermore, MET signaling promoted EGFR-driven migration and invasion. Finally, EGFR-MET signaling was enhanced in a highly metastatic EGFR-mutant cell subpopulation, compared with the indolent parental line, and MET attenuation decreased the incidence of brain metastasis. Overall, our results establish that EGFR-MET signaling is critical for aggressive behavior of NSCLCs and rationalize its continued investigation as a therapeutic target for tumors harboring both wild-type and mutant EGFR at early stages of progression.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Brain Neoplasms / genetics
  • Brain Neoplasms / metabolism
  • Brain Neoplasms / secondary*
  • Carcinoma, Non-Small-Cell Lung / genetics
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / pathology*
  • Carcinoma, Non-Small-Cell Lung / secondary
  • Cell Movement / genetics
  • Epidermal Growth Factor / genetics
  • Epidermal Growth Factor / metabolism
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism*
  • Humans
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology*
  • Mice
  • Mitogen-Activated Protein Kinases / genetics
  • Mitogen-Activated Protein Kinases / metabolism*
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • Oncogene Proteins v-erbB / genetics
  • Oncogene Proteins v-erbB / metabolism
  • Phosphorylation
  • Proto-Oncogene Proteins c-met / genetics
  • Proto-Oncogene Proteins c-met / metabolism*
  • Receptor, ErbB-3 / genetics
  • Receptor, ErbB-3 / metabolism

Substances

  • Oncogene Proteins v-erbB
  • Epidermal Growth Factor
  • ErbB Receptors
  • Proto-Oncogene Proteins c-met
  • Receptor, ErbB-3
  • Mitogen-Activated Protein Kinases