title: Compounds identified by virtual docking to a tetrameric EGFR extracellular domain can modulate Grb2 internalization.
abstract: BACKGROUND
  Overexpression or mutation of the epidermal growth factor receptor (EGFR) potently enhances the growth of many solid tumors. Tumor cells frequently display resistance to mechanistically-distinct EGFR-directed therapeutic agents, making it valuable to develop therapeutics that work by additional mechanisms. Current EGFR-targeting therapeutics include antibodies targeting the extracellular domains, and small molecules inhibiting the intracellular kinase domain. Recent studies have identified a novel prone extracellular tetrameric EGFR configuration, which we identify as a potential target for drug discovery.
  
  
  METHODS
  Our focus is on the prone EGFR tetramer, which contains a novel protein-protein interface involving extracellular domain III. This EGFR tetramer is computationally targeted for stabilization by small molecule ligand binding. This study performed virtual screening of a Life Chemicals, Inc. small molecule library of 345,232 drug-like compounds against a molecular dynamics simulation of protein-protein interfaces distinct to the novel tetramer. One hundred nine chemically diverse candidate molecules were selected and evaluated using a cell-based high-content imaging screen that directly assessed induced internalization of the EGFR effector protein Grb2. Positive hits were further evaluated for influence on phosphorylation of EGFR and its effector ERK1/2.
  
  
  RESULTS
  Fourteen hit compounds affected internalization of Grb2, an adaptor responsive to EGFR activation. Most hits had limited effect on cell viability, and minimally influenced EGFR and ERK1/2 phosphorylation. Docked hit compound poses generally include Arg270 or neighboring residues, which are also involved in binding the effective therapeutic cetuximab, guiding further chemical optimization.
  
  
  CONCLUSIONS
  These data suggest that the EGFR tetrameric configuration offers a novel cancer drug target.
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Ursula.Ramirez@fccc.edu.
authors.forename: Ursula D
authors.initials: UD
authors.lastname: Ramirez
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Anna.Nikonova@fccc.edu.
authors.forename: Anna S
authors.initials: AS
authors.lastname: Nikonova
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. hanqing@ujs.edu.cn.
authors.forename: Hanqing
authors.initials: H
authors.lastname: Liu
authors.affiliation: Translational Facility, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. anna_pech@yahoo.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Pecherskaya
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Sarah.Lawrence@fccc.edu.
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Lawrence
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Ilya.Serebriiskii@fccc.edu.|Kazan Federal University, Kazan, Russia. Ilya.Serebriiskii@fccc.edu.
authors.forename: Ilya G
authors.initials: IG
authors.lastname: Serebriiskii
authors.affiliation: Biostatistics and Bioinformatics Facility, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Yan.Zhou@fccc.edu.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Matthew.Robinson@fccc.edu.
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Robinson
authors.affiliation: Translational Facility, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Margret.Einarson@fccc.edu.
authors.forename: Margret B
authors.initials: MB
authors.lastname: Einarson
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Erica.Golemis@fccc.edu.
authors.forename: Erica A
authors.initials: EA
authors.lastname: Golemis
authors.affiliation: Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA. Eileen.Jaffe@fccc.edu.
authors.forename: Eileen K
authors.initials: EK
authors.lastname: Jaffe
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000188:drug therapy*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D000068818:Cetuximab / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D000069347:Erlotinib Hydrochloride / Q000494:pharmacology; D051380:GRB2 Adaptor Protein / Q000378:metabolism*; D006258:Head and Neck Neoplasms / Q000188:drug therapy*; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D010766:Phosphorylation / Q000187:drug effects; D054730:Protein Interaction Domains and Motifs; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects*; D015398:Signal Transduction
chemical_list: D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D047428:Protein Kinase Inhibitors; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D000068818:Cetuximab