Inhibition of triple-negative breast cancer models by combinations of antibodies to EGFR

Proc Natl Acad Sci U S A. 2013 Jan 29;110(5):1815-20. doi: 10.1073/pnas.1220763110. Epub 2013 Jan 14.

Abstract

Breast tumors lacking expression of human epidermal growth factor receptor 2 (HER2) and the estrogen and the progesterone receptors (triple negative; TNBC) are more aggressive than other disease subtypes, and no molecular targeted agents are currently available for their treatment. Because TNBC commonly displays EGF receptor (EGFR) expression, and combinations of monoclonal antibodies to EGFR effectively inhibit other tumor models, we addressed the relevance of this strategy to treatment of TNBC. Unlike a combination of the clinically approved monoclonal antibodies, cetuximab and panitumumab, which displaced each other and displayed no cooperative effects, several other combinations resulted in enhanced inhibition of TNBC's cell growth both in vitro and in animals. The ability of certain antibody mixtures to remove EGFR from the cell surface and to promote its intracellular degradation correlated with the inhibitory potential. However, unlike EGF-induced sorting of EGFR to lysosomal degradation, the antibody-induced pathway displayed independence from the intrinsic kinase activity and dimer formation ability of EGFR, and it largely avoided the recycling route. In conclusion, although TNBC clinical trials testing EGFR inhibitors reported lack of benefit, our results offer an alternative strategy that combines noncompetitive antibodies to achieve robust degradation of EGFR and tumor inhibition.

Publication types

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

MeSH terms

  • Animals
  • Antibodies, Monoclonal / administration & dosage
  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Cell Line
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Cetuximab
  • ErbB Receptors / antagonists & inhibitors*
  • ErbB Receptors / metabolism
  • Female
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Mice
  • Mice, Nude
  • Panitumumab
  • Proteolysis / drug effects
  • Receptor, ErbB-2 / metabolism
  • Receptors, Estrogen / metabolism
  • Receptors, Progesterone / metabolism
  • Tumor Burden / drug effects
  • Xenograft Model Antitumor Assays*

Substances

  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Receptors, Estrogen
  • Receptors, Progesterone
  • Panitumumab
  • ErbB Receptors
  • Receptor, ErbB-2
  • Cetuximab