Fluorescence study for selecting specific ligands toward HER2 receptor: an example of receptor fragment approach.

Fluorescence titrations allowed us to study the interaction process between Herceptin (Fab)-derived peptides and a synthetic peptide mimicking a subdomain IV of the receptor HER2 (HER2-DIVMP). For some of the investigated peptide/HER2-DIVMP complexes a nanomolar dissociation constant was found. The performed interaction studies were completely immune from interferences of other receptor domains not covered by the design, thus decreasing the possibilities of selecting potential ligands able to bind other subtypes of HER2 receptor family. Our results demonstrate that the adopted receptor fragment approach represents an efficient methodology for selecting new molecules as lead structures specific for the receptor target. For these reasons the optimized compounds could be employed as delivery agents for the receptor-mediated anticancer therapy.