Selection of peptides and synthesis of pentameric peptabody molecules reacting specifically with ErbB-2 receptor.
The HER-2/ErbB-2 oncoprotein is overexpressed in human breast and ovarian adenocarcinomas and is clearly associated with the malignant phenotype. Although no specific ligand for this receptor has been positively identified, ErbB-2 was shown to play a central role in a network of interactions with the related ErbB-1, ErbB-3 and ErbB-4 receptors. We have selected new peptides binding to ErbB-2 extracellular domain protein (ECD) by screening 2 newly developed constrained and unconstrained random hexapeptide phage libraries. Out of 37 phage clones, which bound specifically to ErbB-2 ECD, we found 6 constrained and 10 linear different hexapeptide sequences. Among the latter, 5 consensus motifs, all with a common methionine and a positively charged residue at positions 1 and 3, respectively, were identified. Furthermore, 3 representative hexapeptides were fused to a coiled-coil pentameric recombinant protein to form the so-called peptabodies recently developed in our laboratory. The 3 peptabodies bound specifically to the ErbB-2 ECD, as determined by enzyme-linked immunosorbent assay and BIAcore analysis and to tumor cells overexpressing ErbB-2, as shown by flow cytometry. Interestingly, one of the free selected linear peptides and all 3 peptabodies inhibited the proliferation of tumor cells overexpressing ErbB-2. In conclusion, a novel type of ErbB-2-specific ligand is described that might complement presently available monoclonal antibodies.
Houimel
M
M
Institute of Biochemistry, University of Lausanne, Lausanne, Switzerland.
Schneider
P
P
Terskikh
A
A
Mach
J P
JP
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000378:metabolism*; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism*; D019151:Peptide Library; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D009842:Oligopeptides; D019151:Peptide Library; D018719:Erb-b2 Receptor Tyrosine Kinases