title: Click-chemistry strategy for labeling antibodies with copper-64 via a cross-bridged tetraazamacrocyclic chelator scaffold.
abstract: We report a click-chemistry based modular strategy for antibody labeling with (64)Cu (t1/2 = 12.7 h; β(+) 0.656 MeV, 17.4%; β(-) 0.573 MeV, 39%; EC 43%) under ambient condition utilizing a cross-bridged tetraazamacrocyclic (CB-TE2A) analogue, which otherwise requires harsh conditions that make the CB-TE2A analogues under-utilized for protein labeling despite the fact that they form kinetically inert copper complexes with high in vivo stability. Our strategy involves prelabeling a CB-TE2A based scaffold (CB-TE2A-1C) with (64)Cu and its subsequent reaction with an antibody via the tetrazine-norbornene mediated click chemistry. The effectiveness of this strategy was demonstrated by labeling two monoclonal antibodies, an anti-PSMA antibody (YPSMA-1) and a chimeric anti-phosphatidylserine antibody (Bavituximab). The immunoreactivity of the antibodies remained unchanged after the tetrazine modification and click-chemistry (64)Cu labeling. To further demonstrate the practicality of the modular (64)Cu labeling strategy, we tested positron emission tomography (PET) imaging of tumor with the (64)Cu-labeled bavituximab in a mouse xenograft model. The tumor visualization and uptake of the labeled antibody exhibited the versatility of the click-chemistry strategy.
authors.affiliation: †Departments of Radiology and ‡Urology, and §Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States.
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.affiliation: †Departments of Radiology and ‡Urology, and §Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States.
authors.forename: Guiyang
authors.initials: G
authors.lastname: Hao
authors.affiliation: †Departments of Radiology and ‡Urology, and §Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: †Departments of Radiology and ‡Urology, and §Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States.
authors.forename: Saleh
authors.initials: S
authors.lastname: Ramezani
authors.affiliation: †Departments of Radiology and ‡Urology, and §Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States.
authors.forename: Jer-Tsong
authors.initials: JT
authors.lastname: Hsieh
authors.affiliation: †Departments of Radiology and ‡Urology, and §Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States.
authors.forename: Orhan K
authors.initials: OK
authors.lastname: Öz
authors.affiliation: †Departments of Radiology and ‡Urology, and §Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States.
authors.forename: Xiankai
authors.initials: X
authors.lastname: Sun
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000235:genetics / Q000648:ultrastructure; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000493:pharmacokinetics; D000954:Antigens, Surface / Q000235:genetics / Q000378:metabolism; D002614:Chelating Agents / Q000138:chemical synthesis* / Q000737:chemistry; D057930:Click Chemistry; D003301:Copper Radioisotopes / Q000737:chemistry*; D015870:Gene Expression; D043425:Glutamate Carboxypeptidase II / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006573:Heterocyclic Compounds, 1-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D006801:Humans; D008297:Male; D051379:Mice; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000235:genetics / Q000648:ultrastructure; D019275:Radiopharmaceuticals / Q000737:chemistry*; D013194:Staining and Labeling / Q000379:methods; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D002614:Chelating Agents; D003301:Copper Radioisotopes; D006573:Heterocyclic Compounds, 1-Ring; D019275:Radiopharmaceuticals; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II; C547825:bavituximab