title: Atomic force microscopy study of the effect of HER 2 antibody on EGF mediated ErbB ligand-receptor interaction.
abstract: HER2, a member of the epidermal growth factor receptor (ErbB) family, is over-expressed in many cancers. Trastuzumab and Pertuzumab are two monoclonal antibodies targeting different extracellular domains of HER2 for cancer therapy. As Pertuzumab binds to the dimerization arm of HER2, it can block HER2 heterodimerization and in turn ErbB signaling. Whether Trastuzumab has the same function is unclear. In this work, we have applied living-cell single-molecule force spectroscopy (SMFS) by Atomic Force Microscopy (AFM) to investigate the effect of Trastuzumab, as well as Pertuzumab, on HER2-modulated EGF-EGFR interaction. The results demonstrated that EGF bound to EGFR more stably in the cells co-expressing EGFR and HER2, and the binding enhancement in the presence of HER2 was inhibited by either Trastuzumab or Pertuzumab. Trastuzumab is expected to exert a similar inhibition effect on HER2/EGFR dimerization as Pertuzumab, although it does not bind directly to the dimerization arm of HER2.
  
  
  BACKGROUND
  Living-cell single-molecule force spectroscopy (SMFS) combined by Atomic Force Microscopy (AFM) was used by this team of scientists to investigate the effect of two monoclonal antibodies used in cancer therapy, Trastuzumab and Pertuzumab, on HER2-modulated EGF-EGFR interaction, demonstrating the utility of this technique in characterizing the effects of protein-based therapeutics on membrane receptors.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
authors.forename: Xuejie
authors.initials: X
authors.lastname: Zhang
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shi
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Jinghe
authors.initials: J
authors.lastname: Yuan
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Fang
mesh_terms: D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D018625:Microscopy, Atomic Force; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology; D011485:Protein Binding; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D000068878:Trastuzumab
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D008024:Ligands; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C512478:EGFR protein, human; C485206:pertuzumab