Fibroblast growth factor receptor 3‐mediated reactivation of ERK signaling promotes head and neck squamous cancer cell insensitivity to MEK inhibition

摘要

Recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) has been a longstanding challenge for head and neck oncologists, and current treatments still have limited efficacy. ERK is aberrantly overexpressed and activated in HNSCC. Herein, we aimed to investigate the cause of the limited therapeutic effect of selumetinib, a selective inhibitor of MEK in HNSCC, as MEK/ERK reactivation inevitably occurs. We assessed the effects of combining selumetinib with fibroblast growth factor receptor 3 (FGFR3) inhibitor (PD173074) on tumor growth. Selumetinib transiently inhibited MAPK signaling and reactivated ERK signaling in HNSCC cells. Rebound in the ERK and Akt pathways in HNSCC cells was accompanied by increased FGFR3 signaling after selumetinib treatment. Feedback activation of FGFR3 was a result of autocrine secretion of the style="fixed-case">FGF2 ligand. The style="fixed-case">FGFR3 inhibitor style="fixed-case">PD173074 prevented style="fixed-case">MAPK rebound and sensitized the response of style="fixed-case">HNSCC cells to selumetinib. These results provided rational therapeutic strategies for clinical studies of this subtype of patients that show a poor prognosis with selumetinib. Our data provide a rationale for combining a style="fixed-case">MEK inhibitor with inhibitors of feedback activation of style="fixed-case">FGFR3 signaling in style="fixed-case">HNSCC cells. style="fixed-case">ERK rebound as a result of the upregulation of style="fixed-case">FGFR3 and the ligand style="fixed-case">FGF2 diminished the antitumor effects of selumetinib, which was overcome by combination treatment with the style="fixed-case">FGFR3 inhibitor.