Critical roles for EGFR and EGFR-HER2 clusters in EGF binding of SW620 human carcinoma cells

Adam J M Wollman, Charlotte Fournier, Isabel Llorente-Garcia, Oliver Harriman, Alex L Payne-Dwyer, Sviatlana Shashkova, Peng Zhou, Ta-Chun Liu, Djamila Ouaret, Jenny Wilding, Akihiro Kusumi, Walter Bodmer, Mark C Leake

Research output: Contribution to journalArticlepeer-review


Epidermal growth factor (EGF) signalling regulates normal epithelial and other cell growth, with EGF receptor (EGFR) overexpression reported in many cancers. However, the role of EGFR clusters in cancer and their dependence on EGF binding is unclear. We present novel single-molecule total internal reflection fluorescence microscopy of (i) EGF and EGFR in living cancer cells, (ii) the action of anti-cancer drugs that separately target EGFR and human EGFR2 (HER2) on these cells and (iii) EGFR-HER2 interactions. We selected human epithelial SW620 carcinoma cells for their low level of native EGFR expression, for stable transfection with fluorescent protein labelled EGFR, and imaged these using single-molecule localization microscopy to quantify receptor architectures and dynamics upon EGF binding. Prior to EGF binding, we observe pre-formed EGFR clusters. Unexpectedly, clusters likely contain both EGFR and HER2, consistent with co-diffusion of EGFR and HER2 observed in a different model CHO-K1 cell line, whose stoichiometry increases following EGF binding. We observe a mean EGFR : EGF stoichiometry of approximately 4 : 1 for plasma membrane-colocalized EGFR-EGF that we can explain using novel time-dependent kinetics modelling, indicating preferential ligand binding to monomers. Our results may inform future cancer drug developments.

Original languageEnglish
Article number20220088
Number of pages11
JournalJournal of the Royal Society Interface
Issue number190
Publication statusPublished - 25 May 2022

Bibliographical note

© 2022 The Authors


  • Carcinoma/metabolism
  • Cell Line, Tumor
  • Colonic Neoplasms/metabolism
  • Epidermal Growth Factor/metabolism
  • ErbB Receptors/metabolism
  • Humans
  • Phosphorylation
  • Receptor, ErbB-2/metabolism
  • Signal Transduction

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