Inhibition of epithelial-mesenchymal transition by cetuximab via the EGFR-GEP100-Arf6-AMAP1 pathway in head and neck cancer.

BACKGROUND Despite improved survival by the addition of a monoclonal antibody against epidermal growth factor receptor (EGFR), cetuximab, to chemotherapy or radiotherapy for squamous cell carcinoma of the head and neck (SCCHN), cetuximab by itself is not a potent antiproliferative agent against SCCHN. We aimed to elucidate working mechanism of cetuximab in SCCHN. METHODS The effect of cetuximab on the proliferation, migration, invasion, epithelial-mesenchymal transition, and signaling events downstream of the EGFR were investigated in 4 SCCHN cell lines. The in vivo efficacy of cetuximab was evaluated in a xenotransplant model. RESULTS Cetuximab inhibited migration, invasion, epithelial-mesenchymal transition, and lymph node metastasis by suppressing EGFR-GEP100-Arf6-AMAP1 pathway, but it did not inhibit cancer cell proliferation. CONCLUSION The improved survival by the addition of cetuximab is likely to be attributable to the antiepithelial-mesenchymal transition action of cetuximab via inhibiting EGFR-GEP100-Arf6-AMAP1 pathway. © 2016 Wiley Periodicals, Inc. Head Neck 39: 476-485, 2017.