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Evaluation of a 3-hydroxypyridin-2-one (2,3-HOPO) Based Macrocyclic Chelator for Zr-89(4+) and Its Use for ImmunoPET Imaging of HER2 Positive Model of Ovarian Carcinoma in Mice
Journal article   Open access   Peer reviewed

Evaluation of a 3-hydroxypyridin-2-one (2,3-HOPO) Based Macrocyclic Chelator for Zr-89(4+) and Its Use for ImmunoPET Imaging of HER2 Positive Model of Ovarian Carcinoma in Mice

Jeff N. Tinianow, Darpan N. Pandya, Sylvie L. Pailloux, Annie Ogasawara, Alexander N. Vanderbilt, Herman S. Gill, Simon-P. Williams, Thaddeus J. Wadas, Darren Magda and Jan Marik
Theranostics, Vol.6(4), pp.511-521
01/01/2016
DOI: 10.7150/thno.14261
PMCID: PMC4775861
PMID: 26941844
url
https://doi.org/10.7150/thno.14261View
Published (Version of record) Open Access

Abstract

A novel octadentate 3-hydroxypyridin-2-one (2,3-HOPO) based di-macrocyclic ligand was evaluated for chelation of Zr-89; subsequently, it was used as a bi-functional chelator for preparation of Zr-89-labeled antibodies. Quantitative chelation of Zr-89(4+) with the octadentate ligand forming (ZrL)-Zr-89 complex was achieved under mild conditions within 15 minutes. The Zr-89-complex was stable in vitro in presence of DTPA, but a slow degradation was observed in serum. In vivo, the hydrophilic Zr-89-complex showed prevalently renal excretion; and an elevated bone uptake of radioactivity suggested a partial release of Zr-89(4+) from the complex. The 2,3-HOPO based ligand was conjugated to the monoclonal antibodies, HER2-specific trastuzumab and an isotypic anti-gD antibody, using a p-phenylene bis-isothiocyanate linker to yield products with an average loading of less than 2 chelates per antibody. Conjugated antibodies were labeled with Zr-89 under mild conditions providing the PET tracers in 60-69% yield. Despite the limited stability in mouse serum; the PET tracers performed very well in vivo. The PET imaging in mouse model of HER2 positive ovarian carcinoma showed tumor uptake of Zr-89-trastuzumab (29.2 +/- 12.9 % ID/g) indistinguishable (p = 0.488) from the uptake of positive control Zr-89-DFO-trastuzumab (26.1 +/- 3.3 % ID/g). In conclusion, the newly developed 3-hydroxypyridin-2-one based di-macrocyclic chelator provides a viable alternative to DFO-based heterobifunctional ligands for preparation of Zr-89-labeled monoclonal antibodies for immunoPET studies.
Life Sciences & Biomedicine Medicine, Research & Experimental Research & Experimental Medicine Science & Technology

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