Cetuximab Resistance in Squamous Carcinomas of the Upper Aerodigestive Tract Is Driven by Receptor Tyrosine Kinase Plasticity: Potential for mAb Mixtures

Mol Cancer Ther. 2016 Jul;15(7):1614-26. doi: 10.1158/1535-7163.MCT-15-0565. Epub 2016 May 11.


Squamous cell carcinomas (SCC) arising in upper parts of the aerodigestive tract are among the leading causes of death worldwide. EGFR has been found to play an essential role in driving the malignancy of SCC of the upper aerodigestive tract (SCCUAT), but, despite this, clinical results using a range of different EGFR-targeted agents have been disappointing. Cetuximab is currently the only EGFR-targeted agent approved by the FDA for treatment of SCCUAT. However, intrinsic and acquired cetuximab resistance is a major problem for effective therapy. Thus, a better understanding of the mechanisms responsible for cetuximab resistance is valuable for development of the next generation of antibody therapeutics. In order to better understand the underlying mechanisms of cetuximab resistance in SCCUAT, we established from cetuximab-sensitive models cell lines with acquired resistance to cetuximab by continuous selective pressure in vitro and in vivo Our results show that resistant clones maintain partial dependency on EGFR and that receptor tyrosine kinase plasticity mediated by HER3 and IGF1R plays an essential role. A multitarget mAb mixture against EGFR, HER3, and IGF1R was able to overcome cetuximab resistance in vitro To our surprise, these findings could be extended to include SCCUAT cell lines with intrinsic resistance to cetuximab, suggesting that the triad consisting of EGFR, HER3, and IGF1R plays a key role in SCCUAT. Our results thus provide a rationale for simultaneous targeting of EGFR, HER3, and IGF1R in SCCUAT. Mol Cancer Ther; 15(7); 1614-26. ©2016 AACR.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / pharmacology
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cetuximab / pharmacology*
  • Digestive System Neoplasms / genetics
  • Digestive System Neoplasms / metabolism*
  • Drug Resistance, Neoplasm* / genetics
  • ErbB Receptors / antagonists & inhibitors
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism
  • Female
  • Gene Expression
  • Humans
  • Mice
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / metabolism*
  • Receptor, ErbB-3 / antagonists & inhibitors
  • Receptor, ErbB-3 / genetics
  • Receptor, ErbB-3 / metabolism
  • Receptor, IGF Type 1 / antagonists & inhibitors
  • Receptor, IGF Type 1 / genetics
  • Receptor, IGF Type 1 / metabolism


  • Antibodies, Monoclonal
  • Antineoplastic Agents
  • ErbB Receptors
  • Receptor Protein-Tyrosine Kinases
  • Receptor, ErbB-3
  • Receptor, IGF Type 1
  • Cetuximab