title: High Affinity Binders to EphA2 Isolated from Abdurin Scaffold Libraries; Characterization, Binding and Tumor Targeting.
abstract: Abdurins are a novel antibody-like scaffold derived from the engineering of a single isolated CH2 domain of human IgG. Previous studies established the prolonged serum half-life of Abdurins, the result of a retained FcRn binding motif. Here we present data on the construction of large, diverse, phage-display and cell-free DNA display libraries and the isolation of high affinity binders to the cancer target, membrane-bound ephrin receptor tyrosine kinase class A2 (EphA2). Antigen binding regions were created by designing combinatorial libraries into the structural loops and Abdurins were selected using phage display methods. Initial binders were reformatted into new maturation libraries and low nanomolar binders were isolated using cell-free DNA display, CIS display. Further characterization confirmed binding of the Abdurins to both human and murine EphA2 proteins and exclusively to cell lines that expressed EphA2, followed by rapid internalization. Two different EphA2 binders were labeled with 64Cu, using a bifunctional MeCOSar chelator, and administered to mice bearing tumors from transplanted human prostate cancer cells, followed by PET/CT imaging. The anti-EphA2 Abdurins localized in the tumors as early as 4 hours after injection and continued to accumulate up to 48 hours when the imaging was completed. These data demonstrate the ability to isolate high affinity binders from the engineered Abdurin scaffold, which retain a long serum half-life, and specifically target tumors in a xenograft model.
authors: Isogenica, Ltd. Cambridge, United Kingdom.
authors: Christopher
authors: C
authors: Ullman
authors: Isogenica, Ltd. Cambridge, United Kingdom.
authors: Pascale
authors: P
authors: Mathonet
authors: Isogenica, Ltd. Cambridge, United Kingdom.
authors: Arkadiusz
authors: A
authors: Oleksy
authors: Isogenica, Ltd. Cambridge, United Kingdom.
authors: Agata
authors: A
authors: Diamandakis
authors: IRBM Science Park, Rome, Italy.
authors: Licia
authors: L
authors: Tomei
authors: IRBM Science Park, Rome, Italy.
authors: Anna
authors: A
authors: Demartis
authors: IRBM Science Park, Rome, Italy.
authors: Chiara
authors: C
authors: Nardi
authors: IRBM Science Park, Rome, Italy.
authors: Sonia
authors: S
authors: Sambucini
authors: IRBM Science Park, Rome, Italy.
authors: Antonino
authors: A
authors: Missineo
authors: Vascular Biotechnology, Baker IDI, Melbourne, Australia.
authors: Karen
authors: K
authors: Alt
authors: Vascular Biotechnology, Baker IDI, Melbourne, Australia.
authors: Christoph E
authors: CE
authors: Hagemeyer
authors: Clarity Pharmaceuticals, Ltd. Sydney, Australia.
authors: Matt
authors: M
authors: Harris
authors: Clarity Pharmaceuticals, Ltd. Sydney, Australia.
authors: Amos
authors: A
authors: Hedt
authors: VTU Technology, Grambach, Austria.
authors: Roland
authors: R
authors: Weis
authors: Research Corporation Technologies, Inc. Tucson, Arizona, United States of America.
authors: Kurt R
authors: KR
authors: Gehlsen
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry*; D045744:Cell Line, Tumor; D006801:Humans; D051379:Mice; D019151:Peptide Library; D049268:Positron-Emission Tomography; D015202:Protein Engineering / Q000379:methods*; D036104:Receptor, EphA2 / Q000378:metabolism*; D014057:Tomography, X-Ray Computed; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D019151:Peptide Library; D036104:Receptor, EphA2