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.
Original language | English |
---|---|
Article number | 436 |
Pages (from-to) | 436 |
Journal | BMC Cancer |
Volume | 15 |
Issue number | 1 |
DOIs | |
State | Published - May 28 2015 |
Keywords
- Epidermal growth factor receptor
- Extracellular domain
- Grb2
- Protein multimerization
- GRB2 Adaptor Protein/metabolism
- Protein Transport/drug effects
- Signal Transduction
- Humans
- Cell Survival/drug effects
- Cetuximab/pharmacology
- ErbB Receptors/antagonists & inhibitors
- Mitogen-Activated Protein Kinase 1/metabolism
- Molecular Dynamics Simulation
- Mitogen-Activated Protein Kinase 3/metabolism
- Carcinoma, Squamous Cell/drug therapy
- Cell Line, Tumor
- Molecular Docking Simulation
- Protein Interaction Domains and Motifs
- Protein Kinase Inhibitors/pharmacology
- Drug Evaluation, Preclinical
- Erlotinib Hydrochloride/pharmacology
- Head and Neck Neoplasms/drug therapy
- Phosphorylation/drug effects