title: Enzyme-mediated methodology for the site-specific radiolabeling of antibodies based on catalyst-free click chemistry.
abstract: An enzyme- and click chemistry-mediated methodology for the site-selective radiolabeling of antibodies on the heavy chain glycans has been developed and validated. To this end, a model system based on the prostate specific membrane antigen-targeting antibody J591, the positron-emitting radiometal (89)Zr, and the chelator desferrioxamine has been employed. The methodology consists of four steps: (1) the removal of sugars on the heavy chain region of the antibody to expose terminal N-acetylglucosamine residues; (2) the incorporation of azide-modified N-acetylgalactosamine monosaccharides into the glycans of the antibody; (3) the catalyst-free click conjugation of desferrioxamine-modified dibenzocyclooctynes to the azide-bearing sugars; and (4) the radiolabeling of the chelator-modified antibody with (89)Zr. The site-selective labeling methodology has proven facile, reproducible, and robust, producing (89)Zr-labeled radioimmunoconjguates that display high stability and immunoreactivity in vitro (>95%) in addition to highly selective tumor uptake (67.5 ± 5.0%ID/g) and tumor-to-background contrast in athymic nude mice bearing PSMA-expressing subcutaneous LNCaP xenografts. Ultimately, this strategy could play a critical role in the development of novel well-defined and highly immunoreactive radioimmunoconjugates for both the laboratory and clinic.
authors.affiliation: Department of Radiology and the Program in Molecular Pharmacology and Chemistry, Memorial Sloan-Kettering Cancer Center, New York, New York, United States.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Zeglis
authors.forename: Charles B
authors.initials: CB
authors.lastname: Davis
authors.forename: Robert
authors.initials: R
authors.lastname: Aggeler
authors.forename: Hee Chol
authors.initials: HC
authors.lastname: Kang
authors.forename: Aimei
authors.initials: A
authors.lastname: Chen
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Agnew
authors.forename: Jason S
authors.initials: JS
authors.lastname: Lewis
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D057930:Click Chemistry; D003676:Deferoxamine / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D051379:Mice; D008819:Mice, Nude; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry / Q000378:metabolism* / Q000493:pharmacokinetics; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism; D014407:Tumor Cells, Cultured; D015040:Zirconium / Q000737:chemistry / Q000378:metabolism*; D001616:beta-Galactosidase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000906:Antibodies; D009942:Organometallic Compounds; D011134:Polysaccharides; D015040:Zirconium; D001616:beta-Galactosidase; D003676:Deferoxamine