RAS/PI3K crosstalk and cetuximab resistance in head and neck squamous cell carcinoma

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Cetuximab targets the EGF receptor and is effective for head and neck squamous cell cancer (HNSCC).
• Intrinsic or acquired resistance to cetuximab limits treatment success in HNSCC.
• The mechanisms underlying cetuximab resistance are not fully understood.

Purpose of the Study:

• To investigate the role of oncogenic HRAS in cetuximab resistance in HNSCC.
• To identify a gene expression signature associated with RAS-driven cetuximab resistance.

Main Methods:

• Analysis of HRAS mutations in 180 HNSCC specimens.
• Utilized cetuximab-resistant cell lines and a transgenic mouse model of RAS-driven oral cancer.
• Identified an oncogenic RAS-specific gene expression signature.

Main Results:

• Activation of RAS signaling leads to persistent ERK1/2 signaling and cetuximab resistance.
• HRAS depletion restored cetuximab sensitivity in cells with oncogenic HRAS or PIK3CA.
• A subset of HNSCC patients with HRAS mutations showed de novo resistance to cetuximab.

Conclusions:

• Oncogenic HRAS promotes cetuximab resistance in HNSCC via ERK signaling activation.
• A specific gene expression signature is implicated in RAS-activated HNSCC resistance.
• Findings reveal a distinct mechanism of cetuximab resistance driven by oncogenic HRAS.