Receptor overexpression or inhibition alters cell surface dynamics of EGF-EGFR interaction: New insights from real-time single molecule analysis

Chenxu Yu, Jacob Hale, Kenneth Ritchie, Nagendra K. Prasad, Joseph Irudayaraj

Research output: Contribution to journalArticle

Abstract

Binding of Epidermal growth factor (EGF) to epidermal growth factor receptor (EGFR) in two types of cancer cells (HeLa; 5 × 104 EGFR/cell) and MDA-MB-468; 2 × 106 EGFR/cell) was studied using Total Internal Reflectance Fluorescence (TIRF) microscopy at single molecule precision. Mathematical modeling of the binding kinetics revealed that cells respond differently to the same concentration of EGF depending on the expression level of EGFR. Compared to Hela, MDA-MB-468 cells show; (a) higher number of pre-formed dimers, (b) improved EGF-EGFR interaction at lower ligand concentrations, and (c) shorter time-lapse between first and second EGF binding to the dimer. Treatment with a pharmacological inhibitor of EGFR, AG1478, produced strikingly different binding kinetics where the extent of pre-formed EGFR dimers increased substantially. Thus, single molecule approaches produce novel, quantitative information on signaling mechanisms of significant biological importance. Surface kinetics could also serve as surrogate markers to predict biological outcome of signaling pathways.

Original languageEnglish (US)
Pages (from-to)376-382
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume378
Issue number3
DOIs
StatePublished - Jan 16 2009
Externally publishedYes

Keywords

  • AG1478
  • Anti-EGFR drugs
  • Cancer cells
  • Dimerization
  • EGF
  • EGFR inhibitor
  • Receptor density
  • TIRF

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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