title: Combination antibody treatment down-regulates epidermal growth factor receptor by inhibiting endosomal recycling.
abstract: Due to its common dysregulation in epithelial-based cancers and extensive characterization of its role in tumor growth, epidermal growth factor receptor (EGFR) is a highly validated target for anticancer therapies. There has been particular interest in the development of monoclonal antibodies (mAbs) targeting EGFR, resulting in two approved mAb-based drugs and several others in clinical trials. It has recently been reported that treatment with combinations of noncompetitive mAbs can induce receptor clustering, leading to synergistic receptor down-regulation. We elucidate three key aspects of this phenomenon. First, we show that highly potent combinations consisting of two noncompetitive mAbs that target EGFR domain 3 reduce surface receptor levels by up to 80% with a halftime of 0.5-5 h in both normal and transformed human cell lines to an extent inversely proportional to receptor density. Second, we find the mechanism underlying down-regulation to be consistent with recycling inhibition. Third, in contrast to the agonism associated with ligand-induced down-regulation, we demonstrate that mAb-induced down-regulation does not activate EGFR or its downstream effectors and it leads to synergistic reduction in migration and proliferation of cells that secrete autocrine ligand. These new insights will aid in ongoing rational design of EGFR-targeted antibody therapeutics.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Jamie B
authors.initials: JB
authors.lastname: Spangler
authors.forename: Jason R
authors.initials: JR
authors.lastname: Neil
authors.forename: Sivan
authors.initials: S
authors.lastname: Abramovitch
authors.forename: Yosef
authors.initials: Y
authors.lastname: Yarden
authors.forename: Forest M
authors.initials: FM
authors.lastname: White
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Lauffenburger
authors.forename: K Dane
authors.initials: KD
authors.lastname: Wittrup
mesh_terms: D000465:Algorithms; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D015153:Blotting, Western; D016466:CHO Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D015536:Down-Regulation / Q000187:drug effects; D004705:Endocytosis / Q000187:drug effects*; D011992:Endosomes / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000276:immunology / Q000378:metabolism*; D005434:Flow Cytometry; D019073:HT29 Cells; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000911:Antibodies, Monoclonal; D004815:Epidermal Growth Factor; D066246:ErbB Receptors