title: Selection and characterization of HER2/neu-binding affibody ligands.
abstract: Affibody (affibody) ligands that are specific for the extracellular domain of human epidermal growth factor receptor 2 (HER2/neu) have been selected by phage display technology from a combinatorial protein library based on the 58 amino acid residue staphylococcal protein A-derived Z domain. The predominant variants from the phage selection were produced in Escherichia coli, purified by affinity chromatography, and characterized by biosensor analyses. Two affibody variants were shown to selectively bind to the extracellular domain of HER2/neu (HER2-ECD), but not to control proteins. One of the variants, denoted His6-ZHER2/neu:4, was demonstrated to bind with nanomolar affinity (approximately 50 nM) to the HER2-ECD molecule at a different site than the monoclonal antibody trastuzumab. Furthermore, radiolabeled His6-ZHER2/neu:4 affibody showed specific binding to native HER2/neu, overexpressed on the SKBR-3 tumor cell line. Such affibody ligands might be considered in tumor targeting applications for radionuclide diagnostics and therapy of adenocarcinomas such as breast and ovarian cancers.
authors.affiliation: Department of Biotechnology, AlbaNova University Center, Kungl Tekniska Högskolan, SE-106 91 Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Wikman
authors.forename: A-C
authors.initials: AC
authors.lastname: Steffen
authors.forename: E
authors.initials: E
authors.lastname: Gunneriusson
authors.forename: V
authors.initials: V
authors.lastname: Tolmachev
authors.forename: G P
authors.initials: GP
authors.lastname: Adams
authors.forename: J
authors.initials: J
authors.lastname: Carlsson
authors.forename: S
authors.initials: S
authors.lastname: Ståhl
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000494:pharmacology; D015374:Biosensing Techniques; D006801:Humans; D007457:Iodine Radioisotopes; D008024:Ligands; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D007457:Iodine Radioisotopes; D008024:Ligands; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab