Atomic force microscopy study of the effect of HER 2 antibody on EGF mediated ErbB ligand–receptor interaction

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.From the Clinical EditorLiving-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.

Graphical AbstractThe effect of the HER2 antibodies on HER2 modulated EGF–EGFR interaction was studied by single molecular force spectroscopy using the EGF modified AFM tip and cells expressing GFP tagged EGFR and RFP tagged HER2. It is demonstrated that binding force of EGF–EGFR was higher in the cells co-expressing HER2 and the binding enhancement after recruiting HER2 was inhibited by either Trastuzumab or Pertuzumab. Results from the dynamic force spectroscopy and the derived dissociation kinetic parameters all indicated that Trastuzumab exerted a similar inhibition effect on HER2/EGFR dimerization, although it does not bind directly to HER2 dimerization arm.Figure optionsDownload high-quality image (231 K)Download as PowerPoint slide