Novel Ubiquitin-derived High Affinity Binding Proteins with Tumor Targeting Properties

• Published in: The Journal of biological chemistry Vol. 289; no. 12; pp. 8493 - 8507
• Main Authors: Lorey, Susan, Fiedler, Erik, Kunert, Anja, Nerkamp, Jörg, Lange, Christian, Fiedler, Markus, Bosse-Doenecke, Eva, Meysing, Maren, Gloser, Manja, Rundfeldt, Chris, Rauchhaus, Una, Hänssgen, Ilka, Göttler, Thomas, Steuernagel, Arnd, Fiedler, Ulrike, Haupts, Ulrich
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 21.03.2014; American Society for Biochemistry and Molecular Biology
• Subjects: Affilin; Animals; Biodistribution; Cell Line; Fibronectins - metabolism; Genomics and Proteomics; Half-life Extension; Humans; Mice; Models, Molecular; Neoplasms - metabolism; Peptide Library; Phage Display; Protein Binding; Protein Engineering; Protein Structure, Tertiary; Scaffold Proteins; Tumor Marker; Ubiquitin; Ubiquitin - chemistry; Ubiquitin - genetics; Ubiquitin - metabolism; Ubiquitin - pharmacokinetics; Ubiquitin; Protein Engineering; Scaffold Proteins; Tumor Marker; Affilin; Phage Display; Biodistribution; Half-life Extension
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M113.519884

Targeting effector molecules to tumor cells is a promising mode of action for cancer therapy and diagnostics. Binding proteins with high affinity and specificity for a tumor target that carry effector molecules such as toxins, cytokines, or radiolabels to their intended site of action are required for these applications. In order to yield high tumor accumulation while maintaining low levels in healthy tissues and blood, the half-life of such conjugates needs to be in an optimal range. Scaffold-based binding molecules are small proteins with high affinity and short systemic circulation. Due to their low molecular complexity, they are well suited for combination with effector molecules as well as half-life extension technologies yielding therapeutics with half-lives adapted to the specific therapy. We have identified ubiquitin as an ideal scaffold protein due to its outstanding biophysical and biochemical properties. Based on a dimeric ubiquitin library, high affinity and specific binding molecules, so-called Affilin® molecules, have been selected against the extradomain B of fibronectin, a target almost exclusively expressed in tumor tissues. Extradomain B-binding molecules feature high thermal and serum stability as well as strong in vitro target binding and in vivo tumor accumulation. Application of several half-life extension technologies results in molecules of largely unaffected affinity but significantly prolonged in vivo half-life and tumor retention. Our results demonstrate the utility of ubiquitin as a scaffold for the generation of high affinity binders in a modular fashion, which can be combined with effector molecules and half-life extension technologies. Background: Targeting molecules to tumor cells is a promising mode of action for cancer therapy. Results: Ubiquitin-based high affinity, specific, and stable binding molecules for extradomain B are accumulated in the tumor. Conclusion: Ubiquitin may be engineered for high affinity target binding and modified with half-life extension technologies. Significance: Ubiquitin qualifies as a well suited scaffold protein adaptable to specific tasks.