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Albanese V, Roccatello C, Pacifico S, Guerrini R, Preti D, Gentili S, Tegoni M, Remelli M, Bellotti D, Amico J, Gorgoni G, Cazzola E. Bifunctional octadentate pseudopeptides as Zirconium-89 chelators for immuno-PET applications. EJNMMI Radiopharm Chem 2024; 9:38. [PMID: 38705946 PMCID: PMC11070408 DOI: 10.1186/s41181-024-00263-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 04/15/2024] [Indexed: 05/07/2024] Open
Abstract
BACKGROUND Positron emission tomography (PET) is a highly sensitive method that provides fine resolution images, useful in the field of clinical diagnostics. In this context, Zirconium-89 (89Zr)-based imaging agents have represented a great challenge in molecular imaging with immuno-PET, which employs antibodies (mAbs) as biological vectors. Indeed, immuno-PET requires radionuclides that can be attached to the mAb to provide stable in vivo conjugates, and for this purpose, the radioactive element should have a decay half-life compatible with the time needed for the biodistribution of the immunoglobulin. In this regard, 89Zr is an ideal radioisotope for immuno-PET because its half-life perfectly matches the in vivo pharmacokinetics of mAbs. RESULTS The main objective of this work was the design and synthesis of a series of bifunctional octadentate pseudopeptides able to generate stable 89Zr complexes. To achieve this, here we investigated hydroxamate, N-methylhydroxamate and catecholate chelating moieties in complexing radioactive zirconium. N-methylhydroxamate proved to be the most effective 89Zr-chelating group. Furthermore, the increased flexibility and hydrophilicity obtained by using polyoxyethylene groups spacing the hydroxamate units led to chelators capable of rapidly forming (15 min) stable and water-soluble complexes with 89Zr under mild reaction conditions (aqueous environment, room temperature, and physiological pH) that are mandatory for complexation reactions involving biomolecules. Additionally, we report challenge experiments with the competitor ligand EDTA and metal ions such as Fe3+, Zn2+ and Cu2+. In all examined conditions, the chelators demonstrated stability against transmetallation. Finally, a maleimide moiety was introduced to apply one of the most promising ligands in bioconjugation reactions through Thiol-Michael chemistry. CONCLUSION Combining solid phase and solution synthesis techniques, we identified novel 89Zr-chelating molecules with a peptide scaffold. The adopted chemical design allowed modulation of molecular flexibility, hydrophilicity, as well as the decoration with different zirconium chelating groups. Best results in terms of 89Zr-chelating properties were achieved with the N-methyl hydroxamate moiety. The Zirconium complexes obtained with the most effective compounds were water-soluble, stable to transmetallation, and resistant to peptidases for at least 6 days. Further studies are needed to assess the potential of this novel class of molecules as Zirconium-chelating agents for in vivo applications.
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Affiliation(s)
- Valentina Albanese
- Department of Environmental and Prevention Sciences, University of Ferrara, Palazzo Turchi di Bagno, C.So Ercole I d'Este 32, 44121, Ferrara, Italy.
| | - Chiara Roccatello
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Salvatore Pacifico
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Remo Guerrini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Delia Preti
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Silvia Gentili
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area Delle Scienze 11/A, 43124, Parma, Italy
| | - Matteo Tegoni
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area Delle Scienze 11/A, 43124, Parma, Italy
| | - Maurizio Remelli
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy.
| | - Denise Bellotti
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Jonathan Amico
- Department of Radiopharmaceutical, IRCCS Sacro Cuore Don Calabria Hospital, Via Don A. Sempreboni 5, 37024, Negrar di Valpolicella, Verona, Italy
| | - Giancarlo Gorgoni
- Department of Radiopharmaceutical, IRCCS Sacro Cuore Don Calabria Hospital, Via Don A. Sempreboni 5, 37024, Negrar di Valpolicella, Verona, Italy
| | - Emiliano Cazzola
- Department of Radiopharmaceutical, IRCCS Sacro Cuore Don Calabria Hospital, Via Don A. Sempreboni 5, 37024, Negrar di Valpolicella, Verona, Italy
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Guarrochena X, Kronberger J, Tieber M, Ciesielski P, Mindt TL, Feiner IVJ. Straightforward Synthesis of DFO* - An Octadentate Chelator for Zirconium-89. ChemMedChem 2024; 19:e202300495. [PMID: 38102942 DOI: 10.1002/cmdc.202300495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/11/2023] [Accepted: 12/15/2023] [Indexed: 12/17/2023]
Abstract
DFO* is an octadentate chelator able to form highly stable chelates with Zirconium-89 (89 Zr) for nuclear medicinal applications in Positron Emission Tomography (PET).[1,2] The synthesis of DFO* and its scale-up remains challenging by reported synthetic protocols. For this reason, we set out to develop a de novo synthesis of a hydroxamate-containing building block suitable for the coupling to the commercially available DFO (desferrioxamine B, mesylate salt) yielding, after deprotection, the desired chelator DFO* in a more efficient procedure. Highlights of the new synthesis of DFO* reported herein are less synthetic steps and the isolation of the desired product DFO* by using solid phase extraction (SPE), thus avoiding tedious HPLC purification. DFO* is obtained in excellent purity (92-98 %) and an overall yield of approximately 29 %. In addition, the isolated trifluoroacetic acid (TFA)-salt of DFO* displays an improved solubility in organic solvents (DMSO, DMF, methanol), which will facilitate its use for the preparation of structurally diverse derivatives suitable for bioconjugation chemistry and the development of 89 Zr-labeled radiotracers.
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Affiliation(s)
- Xabier Guarrochena
- Bioinorganic Radiochemistry, Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria
- Vienna Doctoral School in Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, AKH Wien c/o Sekretariat Nuklearmedizin, Waehringer Guertel 18-20, 1090, Vienna, Austria
- Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Julia Kronberger
- Bioinorganic Radiochemistry, Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria
- Vienna Doctoral School in Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, AKH Wien c/o Sekretariat Nuklearmedizin, Waehringer Guertel 18-20, 1090, Vienna, Austria
- Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Manuel Tieber
- Bioinorganic Radiochemistry, Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria
| | - Philipp Ciesielski
- ABX Advanced Biochemical Compounds, Heinrich-Glaeser-Strasse 10-14, 01454 Radeberg, Germany
| | - Thomas L Mindt
- Bioinorganic Radiochemistry, Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, AKH Wien c/o Sekretariat Nuklearmedizin, Waehringer Guertel 18-20, 1090, Vienna, Austria
- Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
- Joint Applied Medicinal Radiochemistry Facility, University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Irene V J Feiner
- Bioinorganic Radiochemistry, Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, AKH Wien c/o Sekretariat Nuklearmedizin, Waehringer Guertel 18-20, 1090, Vienna, Austria
- Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Ramogida C, Price E. Transition and Post-Transition Radiometals for PET Imaging and Radiotherapy. Methods Mol Biol 2024; 2729:65-101. [PMID: 38006492 DOI: 10.1007/978-1-0716-3499-8_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
Radiometals are an exciting class of radionuclides because of the large number of metallic elements available that have medically useful isotopes. To properly harness radiometals, they must be securely bound by chelators, which must be carefully matched to the radiometal ion to maximize radiolabeling performance and the stability of the resulting complex. This chapter focuses on practical aspects of radiometallation chemistry including chelator selection, radiolabeling procedures and conditions, radiolysis prevention, purification, quality control, requisite equipment and reagents, and useful tips.
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Affiliation(s)
- Caterina Ramogida
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada.
- Life Sciences Division, TRIUMF, Vancouver, BC, Canada.
| | - Eric Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK, Canada
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Salih AK, Dominguez Garcia M, Raheem SJ, Ahiahonu WK, Price EW. DFO-Km: A Modular Chelator as a New Chemical Tool for the Construction of Zirconium-89-Based Radiopharmaceuticals. Inorg Chem 2023; 62:20806-20819. [PMID: 37751491 DOI: 10.1021/acs.inorgchem.3c02714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Zirconium-89-labeled monoclonal antibodies and other large macromolecules such as nanoparticles hold great promise as positron emission tomography imaging agents. In general, zirconium-89 is an ideal radionuclide for long-circulating vectors such as antibodies or nanoparticles. It is also a promising radionuclide for theranostic radiopharmaceuticals due to its suitable match in half-life with actinium-225, thorium-227, lutetium-177, and others. As such, demand for new and optimized bifunctional chelators for zirconium-89 continues to grow. Herein, we present the modular chelator DFO-Km, which is octadentate and features lysine as a modular amino acid linker. The modular amino acid linker can be changed to other natural or unnatural amino acids to access different bioconjugation chemistries, while the chelating portion is unchanged thus retaining identical metal ion coordination properties to DFO-Km. The epsilon-amine in the DFO-Km linker (lysine) was used to complete synthesis of a bifunctional derivative bearing a p-SCN-Ph moiety. The chelator DFO-Km includes a redesigned hydroxamic acid, which provides more flexibility for metal ion coordination relative to the monomer used in the previously published DFO-Em. Moreover, a set of comprehensive DFT calculations were performed to model and evaluate 16 geometric isomers of Zr-(DFO-Km), which suggested the complex would form the optimum cic-cis-trans-trans octadentate Zr(IV) coordination geometry with no aqua or hydroxide ligands present. The bifunctional derivative p-SCN-Ph-DFO-Km was compared directly with the commercially available p-SCN-Ph-DFO, and both underwent efficient conjugation to a nonspecific human serum antibody (IgG) to yield two model immunoconjugates. The behavior of [89Zr]Zr-DFO-Km-IgG was studied in healthy mice for 2 weeks and compared to an equivalent cohort injected with [89Zr]Zr-DFO-IgG as a clinical "gold standard" control. PET-CT and biodistribution results revealed higher stability of [89Zr]Zr-(DFO-Km)-IgG in vivo over [89Zr]Zr-DFO-IgG, as demonstrated by the significant reduction of zirconium-89 in the whole skeleton as visualized and quantified by PET-CT at 1, 3, 7, and 14 days post-injection. Using CT-gated regions of interest over these PET-CT images, the whole skeleton was selected and uptake values were measured at 14 days post-injection of 3.6 ± 0.9 (DFO) vs 1.9 ± 0.1 (DFO-Km) %ID/g (n = 4, * p = 0.02), which represents a ∼48% reduction in bone uptake with DFO-Km relative to DFO. Biodistribution experiments performed on these same mice following the 14 day imaging time point revealed bone (both tibia) uptake values of 3.7 ± 1.3 (DFO) vs 2.0 ± 0.6 (DFO-Km) %ID/g (n = 6, * p < 0.05), with the tibia uptake values in close agreement with whole-skeleton ROI PET-CT data. These results indicate that DFO-Km is an improved chelator for [89Zr]Zr4+ applications relative to DFO. The bifunctional chelator p-SCN-Ph-DFO-Km shows potential as a new chemical tool for creating bioconjugates using targeting vectors such as antibodies, peptides, and nanoparticles.
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Affiliation(s)
- Akam K Salih
- Radiopharmacology, Mariana Oncology, Woburn, Massachusetts 01801, United States
| | - Moralba Dominguez Garcia
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N-5C9, Canada
| | - Shvan J Raheem
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N-5C9, Canada
| | - William K Ahiahonu
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N-5C9, Canada
| | - Eric W Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N-5C9, Canada
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Melendez-Alafort L, Ferro-Flores G, De Nardo L, Ocampo-García B, Bolzati C. Zirconium immune-complexes for PET molecular imaging: Current status and prospects. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.215005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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6
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Khozeimeh Sarbisheh E, Summers KL, Salih AK, Cotelesage JJH, Zimmerling A, Pickering IJ, George GN, Price EW. Radiochemical, Computational, and Spectroscopic Evaluation of High-Denticity Desferrioxamine Derivatives DFO2 and DFO2p toward an Ideal Zirconium-89 Chelate Platform. Inorg Chem 2023; 62:2637-2651. [PMID: 36716427 DOI: 10.1021/acs.inorgchem.2c03573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Desferrioxamine (DFO) has long been considered the gold standard chelator for incorporating [89Zr]Zr4+ in radiopharmaceuticals for positron emission tomography (PET) imaging. To improve the stability of DFO with zirconium-89 and to expand its coordination sphere to enable binding of large therapeutic radiometals, we have synthesized the highest denticity DFO derivatives to date: dodecadentate DFO2 and DFO2p. In this study, we describe the synthesis and characterization of a novel DFO-based chelator, DFO2p, which is comprised of two DFO strands connected by an p-NO2-phenyl linker and therefore contains double the chelating moieties of DFO (potential coordination number up to 12 vs 6). The chelator DFO2p offers an optimized synthesis comprised of only a single reaction step and improves water solubility relative to DFO2, but the shorter linker reduces molecular flexibility. Both DFO2 and DFO2p, each with 6 potential hydroxamate ligands, are able to reach a more energetically favorable 8-coordinate environment for Zr(IV) than DFO. The zirconium(IV) coordination environment of these complexes were evaluated by a combination of density functional theory (DFT) calculations and synchrotron spectroscopy (extended X-ray absorption fine structure), which suggest the inner-coordination sphere of zirconium(IV) to be comprised of the outermost four hydroxamate ligands. These results also confirm a single Zr(IV) in each chelator, and the hydroxide ligands which complete the coordination sphere of Zr(IV)-DFO are absent from Zr(IV)-DFO2 and Zr(IV)-DFO2p. Radiochemical stability studies with zirconium-89 revealed the order of real-world stability to be DFO2 > DFO2p ≫ DFO. The zirconium-89 complexes of these new high-denticity chelators were found to be far more stable than DFO, and the decreased molecular flexibility of DFO2p, relative to DFO2, could explain its decreased stability, relative to DFO2.
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Affiliation(s)
- Elaheh Khozeimeh Sarbisheh
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada
| | - Kelly L Summers
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Akam K Salih
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada
| | - Julien J H Cotelesage
- Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Amanda Zimmerling
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, SKS7N 5A9, Canada
| | - Ingrid J Pickering
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Graham N George
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Eric W Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada
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Salih AK, Raheem SJ, Garcia MD, Ahiahonu WK, Price EW. Design, Synthesis, and Evaluation of DFO-Em: A Modular Chelator with Octadentate Chelation for Optimal Zirconium-89 Radiochemistry. Inorg Chem 2022; 61:20964-20976. [PMID: 36516446 DOI: 10.1021/acs.inorgchem.2c03442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Zirconium-89 has quickly become a favorite radionuclide among academics and clinicians for nuclear imaging. This radiometal has a relatively long half-life, which matches the biological half-life of most antibodies, suitable decay properties for positron emission tomography (PET), and efficient and affordable cyclotron production and purification. The "gold standard" chelator for [89Zr]Zr4+ is desferrioxamine B (DFO), and although it has been used both preclinically and clinically for immunoPET with great success, it has revealed its suboptimal stability in vivo. DFO can only bind to [89Zr]Zr4+ through its six available coordination sites made up by three hydroxamic acid (HA) moieties, which is not sufficient to saturate the coordination sphere (CN 7-8). In this study, we have designed, synthesized, and characterized a new octadentate chelator we have called DFO-Em, which is an improved derivative of our previously published dodecadentate chelator DFO2. This octadentate DFO-Em chelator is smaller than DFO2 but still satisfies the coordination sphere of zirconium-89 and forms a highly stable radiometal-chelator complex. DFO-Em was synthesized by tethering a hydroxamic acid monomer to commercially available DFO using glutamic acid as a linker, providing an octadentate chelator built on a modular amino acid-based synthesis platform. Radiolabeling performance and radiochemical stability of DFO-Em were assessed in vitro by serum stability, ethylenediamine tetraacetic acid (EDTA), and hydroxyapatite challenges. Furthermore, [89Zr]Zr-(DFO-Em) and [89Zr]Zr-DFO were injected in healthy mice and measured in vivo by PET/CT imaging and ex vivo biodistribution. Additionally, the coordination of DFO-Em with Zr(IV) and its isomers was studied using density functional theory (DFT) calculations. The radiolabeling studies revealed that DFO-Em has a comparable radiolabeling profile to the gold standard chelator DFO. The in vitro stability evaluation showed that [89Zr]Zr-(DFO-Em) was significantly more stable than [89Zr]Zr-DFO, and in vivo both had similar clearance in healthy mice with a small decrease in tissue retention for [89Zr]Zr-(DFO-Em) at 24 h post injection. The DFT calculations also confirmed that Zr-(DFO-Em) can adopt highly stable 8-coordinate geometries, which along with NMR characterization suggest no fluxional behavior and the presence of a single isomer. The modular design of DFO-Em means that any natural or unnatural amino acid can be utilized as a linker to gain access to different chemistries (e.g., thiol, amine, carboxylic acid, azide) while retaining an identical coordination sphere to DFO-Em.
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Affiliation(s)
- Akam K Salih
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, S7N-5C9Saskatoon, SKCanada
| | - Shvan J Raheem
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, S7N-5C9Saskatoon, SKCanada
| | - Moralba Dominguez Garcia
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, S7N-5C9Saskatoon, SKCanada
| | - William K Ahiahonu
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, S7N-5C9Saskatoon, SKCanada
| | - Eric W Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, S7N-5C9Saskatoon, SKCanada
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Bubenshchikov VB, Larenkov AA. Chelating Agents for Zirconium-89 in the Synthesis of Radiopharmaceuticals: Current State and Prospects of Development. RUSS J COORD CHEM+ 2022. [DOI: 10.1134/s1070328422110021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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The Race for Hydroxamate-Based Zirconium-89 Chelators. Cancers (Basel) 2021; 13:cancers13174466. [PMID: 34503276 PMCID: PMC8431476 DOI: 10.3390/cancers13174466] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/18/2022] Open
Abstract
Simple Summary Chelators are small molecules that can form a complex with a metal ion by coordinating electron rich atoms from the chelator to the electron-poor cation. Bifunctionalization of the chelator allows for the coupling of the chelator to a vector, such as a biomolecule. Using this approach, radiolabeling of biomolecules with metallic radionuclides can be performed, enabling nuclear imaging studies for diagnosis and radiotherapy of diseases. In the case of positron emission tomography (PET) of radiolabeled antibodies, this approach is called immunoPET. In this review we focus on chelators using hydroxamate groups to coordinate the radionuclide zirconium-89 ([89Zr]Zr4+, denoted as 89Zr in the following). The most common chelator used in this context is desferrioxamine (DFO). However, preclinical studies indicate that the 89Zr-DFO complex is not stable enough in vivo, in particular when combined with biomolecules with slow pharmacokinetics (e.g., antibodies). Subsequently, new chelators with improved properties have been developed, of which some show promising potential. The progress is summarized in this review. Abstract Metallic radionuclides conjugated to biological vectors via an appropriate chelator are employed in nuclear medicine for the diagnosis (imaging) and radiotherapy of diseases. For the application of radiolabeled antibodies using positron emission tomography (immunoPET), zirconium-89 has gained increasing interest over the last decades as its physical properties (t1/2 = 78.4 h, 22.6% β+ decay) match well with the slow pharmacokinetics of antibodies (tbiol. = days to weeks) allowing for late time point imaging. The most commonly used chelator for 89Zr in this context is desferrioxamine (DFO). However, it has been shown in preclinical studies that the hexadentate DFO ligand does not provide 89Zr-complexes of sufficient stability in vivo and unspecific uptake of the osteophilic radiometal in bones is observed. For clinical applications, this might be of concern not only because of an unnecessary dose to the patient but also an increased background signal. As a consequence, next generation chelators based on hydroxamate scaffolds for more stable coordination of 89Zr have been developed by different research groups. In this review, we describe the progress in this research field until end of 2020, including promising examples of new candidates of chelators currently in advanced stages for clinical translation that outrun the performance of the current gold standard DFO.
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Sneddon D, Cornelissen B. Emerging chelators for nuclear imaging. Curr Opin Chem Biol 2021; 63:152-162. [PMID: 34051509 DOI: 10.1016/j.cbpa.2021.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/28/2021] [Accepted: 03/09/2021] [Indexed: 11/25/2022]
Abstract
Chelators are necessary in nuclear medicine imaging to direct an inorganic radionuclide, a radiometal, to a desired target; unfortunately, there is no 'one-size-fits-all' chelator. As the toolbox of radiometals is expanding, new chelators are required to prevent off-target side effects. 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) is the current gold standard chelator for several radiometals, but typically, chelation requires harsh conditions, making it unsuitable to label biological vectors. The ideal chelator would allow labelling under mild conditions (near-neutral pH and low temperatures [∼37 °C]) and be both thermodynamically and kinetically stable. Over the past 2-3 years, several exciting chelators have been developed that have superior properties to make them worth investigating for future clinical applications.
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Affiliation(s)
- Deborah Sneddon
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, United Kingdom.
| | - Bart Cornelissen
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, United Kingdom
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Sharma SK, Glaser JM, Edwards KJ, Sarbisheh EK, Salih AK, Lewis JS, Price EW. A Systematic Evaluation of Antibody Modification and 89Zr-Radiolabeling for Optimized Immuno-PET. Bioconjug Chem 2021; 32:1177-1191. [PMID: 32197571 PMCID: PMC9423892 DOI: 10.1021/acs.bioconjchem.0c00087] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Immuno-PET using desferrioxamine (DFO)-conjugated zirconium-89 ([89Zr]Zr4+)-labeled antibodies is a powerful tool used for preclinical and clinical molecular imaging. However, a comprehensive study evaluating the variables involved in DFO-conjugation and 89Zr-radiolabeling of antibodies and their impact on the in vitro and in vivo behavior of the resulting radioimmunoconjugates has not been adequately performed. Here, we synthesized different DFO-conjugates of the HER2-targeting antibody (Ab)-trastuzumab, dubbed T5, T10, T20, T60, and T200-to indicate the molar equivalents of DFO used for bioconjugation. Next we radiolabeled the immunoconjugates with ([89Zr]Zr4+) under a comprehensive set of reaction conditions including different buffers (PBS, chelexed-PBS, TRIS/HCl, HEPES; ± radioprotectants), different reaction volumes (0.1-1 mL), variable amounts of DFO-conjugated Ab (5, 25, 50 μg), and radioactivity (0.2-1.0 mCi; 7.4-37 MBq). We evaluated the effects of these variables on radiochemical yield (RCY), molar activity (Am)/specific activity (As), immunoreactive fraction, and ultimately the in vivo biodistribution profile and tumor targeting ability of the trastuzumab radioimmunoconjugates. We show that increasing the degree of DFO conjugation to trastuzumab increased the RCY (∼90%) and Am/As (∼194 MBq/nmol; 35 mCi/mg) but decreased the HER2-binding affinity (3.5×-4.6×) and the immunoreactive fraction of trastuzumab down to 50-64%, which translated to dramatically inferior in vivo performance of the radioimmunoconjugate. Cell-based immunoreactivity assays and standard binding affinity analyses using surface plasmon resonance (SPR) did not predict the poor in vivo performance of the most extreme T200 conjugate. However, SPR-based concentration free calibration analysis yielded active antibody concentration and was predictive of the in vivo trends. Positron emission tomography (PET) imaging and biodistribution studies in a HER2-positive xenograft model revealed activity concentrations of 38.7 ± 3.8 %ID/g in the tumor and 6.3 ± 4.1 %ID/g in the liver for ([89Zr]Zr4+)-T5 (∼1.4 ± 0.5 DFOs/Ab) at 120 h after injection of the radioimmunoconjugates. On the other hand, ([89Zr]Zr4+)-T200 (10.9 ± 0.7 DFOs/Ab) yielded 16.2 ± 3.2 %ID/g in the tumor versus 27.5 ± 4.1 %ID/g in the liver. Collectively, our findings suggest that synthesizing trastuzumab immunoconjugates bearing 1-3 DFOs per Ab (T5 and T10) combined with radiolabeling performed in low reaction volumes using Chelex treated PBS or HEPEs without a radioprotectant provided radioimmunoconjugates having high Am/As (97 MBq/nmol; 17.5 ± 2.2 mCi/mg), highly preserved immunoreactive fractions (86-93%), and favorable in vivo biodistribution profile with excellent tumor uptake.
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Affiliation(s)
- Sai Kiran Sharma
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Jonathan M. Glaser
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Kimberly J. Edwards
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | | | - Akam K. Salih
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N-5C9, Canada
| | - Jason S. Lewis
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Radiochemistry and Molecular Imaging Probes Core, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Department of Pharmacology, Weill Cornell Medical College, New York, NY, 10065, USA
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Department of Radiology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Eric W. Price
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N-5C9, Canada
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12
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Klasen B, Lemcke D, Mindt TL, Gasser G, Rösch F. Development and in vitro evaluation of new bifunctional 89Zr-chelators based on the 6-amino-1,4-diazepane scaffold for immuno-PET applications. Nucl Med Biol 2021; 102-103:12-23. [PMID: 34242949 DOI: 10.1016/j.nucmedbio.2021.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/15/2021] [Accepted: 06/25/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Combination of hydroxamate bearing side chains with the 6-amino-1,4-diazepane scaffold provides a promising strategy for fast and stable 89Zr-labeling of antibodies. Following this approach, we hereby present the development, labeling kinetics and in vitro complex stability of three resulting bifunctional chelator derivatives both stand-alone and coupled to a model protein in comparison to different linear deferoxamine (DFO) derivatives. METHODS The novel 89Zr-chelator Hy3ADA5 was prepared via amide-coupling of separately synthesized 6-amino-1,4-diazepane-6-pentanoic acid and hydroxamate-containing side chains. Two further bifunctional derivatives were synthesized by extending the resulting system with either a squaramide- or p-isothiocyanatophenyl moiety for simplified binding to proteins. After coupling to a model antibody and purification, the resulting immunoconjugates as well as the unbound chelator derivatives were 89Zr-labeled at room temperature (RT) and neutral pH. For comparison, different DFO derivatives were analogously coupled, purified and radiolabeled. In vitro complex stability of the resulting radioconjugates was investigated in phosphate buffered saline (PBS) and human serum at 37 °C over a period of 7 days. RESULTS 89Zr-labeling of the novel unbound Hy3ADA5 derivatives indicated rapid complexation kinetics resulting in high radiochemical conversions (RCC) of 84-94% after 90 min. Similar or even faster radiolabeling with slightly increased maximum yields was obtained using the DFO-analogues. Initially, [89Zr]Zr-DFO*-p-Ph-NCS showed a delayed formation, nevertheless reaching almost quantitative complexation. Radiolabeling of the corresponding immunoconjugates Hy3ADA5-SA-mAb and Hy3ADA5-p-Ph-NCS-mAb resulted in 82.0 ± 1.1 and 89.2 ± 0.7% RCC, respectively after 90 min representing high but slightly lower labeling efficiency compared to the DFO- and DFO*-functionalized analogues. All examined radioimmunoconjugates showed very high in vitro complex stability both in human serum and PBS, providing no significant release of the radiometal. In the case of unbound chelators, however, the p-Ph-NCS-functionalized derivatives indicated considerable instability in human serum already after 1 h. CONCLUSION The novel chelator derivatives based on hydroxamate-functionalized 6-amino-1,4-diazepane revealed fast and high yielding 89Zr-labeling kinetics as well as high in vitro complex stability both stand-alone and coupled to an antibody. Therefore, Hy3ADA5 represents a promising tool for radiolabeling of biomolecules such as antibodies at mild conditions for immuno-PET applications.
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Affiliation(s)
- Benedikt Klasen
- Department of Chemistry - TRIGA site, Johannes Gutenberg University Mainz, Germany.
| | - Daniel Lemcke
- Department of Chemistry - TRIGA site, Johannes Gutenberg University Mainz, Germany
| | - Thomas L Mindt
- Ludwig Boltzmann Institute Applied Diagnostics, General Hospital Vienna, Austria; Department of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Austria
| | - Gilles Gasser
- Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Laboratory for Inorganic Chemical Biology, Paris, France
| | - Frank Rösch
- Department of Chemistry - TRIGA site, Johannes Gutenberg University Mainz, Germany.
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13
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Guillou A, Earley DF, Klingler S, Nisli E, Nüesch LJ, Fay R, Holland JP. The Influence of a Polyethylene Glycol Linker on the Metabolism and Pharmacokinetics of a 89Zr-Radiolabeled Antibody. Bioconjug Chem 2021; 32:1263-1275. [PMID: 34056896 DOI: 10.1021/acs.bioconjchem.1c00172] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Most experimental work in the space of bioconjugation chemistry focuses on using new methods to construct covalent bonds between a cargo molecule and a protein of interest such as a monoclonal antibody (mAb). Bond formation is important for generating new diagnostic tools, yet when these compounds advance to preclinical in vitro and in vivo studies, and later for translation to the clinic, understanding the fate of potential metabolites that arise from chemical or enzymatic degradation of the construct is important to obtain a full picture of the pharmacokinetic performance of a new compound. In the context of designing new bioconjugate methods for labeling antibodies with the positron-emitting radionuclide 89Zr, we previously developed a photochemical process for making 89Zr-mAbs. Experimental studies on [89Zr]ZrDFO-PEG3-azepin-mAb constructs revealed that incorporation of the tris-polyethylene glycol (PEG3) linker improved the aqueous phase solubility and radiochemical conversion. However, the use of a PEG3 linker also has an impact on the whole-body residence time of the construct, leading to a more rapid excretion of the 89Zr activity when compared with radiotracers that lack the PEG3 chain. In this work, we investigated the metabolic fate of eight possible metabolites that arise from the logical disconnection of [89Zr]ZrDFO-PEG3-azepin-mAb at bonds which are susceptible to chemical or enzymatic cleavage. Synthesis combined with 89Zr-radiolabeling, small-animal positron emission tomography imaging at multiple time points from 0 to 20 h, and measurements of the effective half-life for whole-body excretion are reported. The conclusions are that the use of a PEG3 linker is non-innocent in terms of its impact on enhancing the metabolism of [89Zr]ZrDFO-PEG3-azepin-mAbs. In most cases, degradation can produce metabolites that are rapidly eliminated from the body, thereby enhancing image contrast by reducing nonspecific accumulation and retention of 89Zr in background organs such as the liver, spleen, kidney, and bone.
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Affiliation(s)
- Amaury Guillou
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057, Zurich, Switzerland
| | - Daniel F Earley
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057, Zurich, Switzerland
| | - Simon Klingler
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057, Zurich, Switzerland
| | - Eda Nisli
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057, Zurich, Switzerland
| | - Laura J Nüesch
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057, Zurich, Switzerland
| | - Rachael Fay
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057, Zurich, Switzerland
| | - Jason P Holland
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057, Zurich, Switzerland
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14
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Chomet M, van Dongen GAMS, Vugts DJ. State of the Art in Radiolabeling of Antibodies with Common and Uncommon Radiometals for Preclinical and Clinical Immuno-PET. Bioconjug Chem 2021; 32:1315-1330. [PMID: 33974403 PMCID: PMC8299458 DOI: 10.1021/acs.bioconjchem.1c00136] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Inert
and stable radiolabeling of monoclonal antibodies (mAb),
antibody fragments, or antibody mimetics with radiometals is a prerequisite
for immuno-PET. While radiolabeling is preferably fast, mild, efficient,
and reproducible, especially when applied for human use in a current
Good Manufacturing Practice compliant way, it is crucial that the
obtained radioimmunoconjugate is stable and shows preserved immunoreactivity
and in vivo behavior. Radiometals and chelators have
extensively been evaluated to come to the most ideal radiometal–chelator
pair for each type of antibody derivative. Although PET imaging of
antibodies is a relatively recent tool, applications with 89Zr, 64Cu, and 68Ga have greatly increased in
recent years, especially in the clinical setting, while other less
common radionuclides such as 52Mn, 86Y, 66Ga, and 44Sc, but also 18F as in [18F]AlF are emerging promising candidates for the radiolabeling
of antibodies. This review presents a state of the art overview of
the practical aspects of radiolabeling of antibodies, ranging from
fast kinetic affibodies and nanobodies to slow kinetic intact mAbs.
Herein, we focus on the most common approach which consists of first
modification of the antibody with a chelator, and after eventual storage
of the premodified molecule, radiolabeling as a second step. Other
approaches are possible but have been excluded from this review. The
review includes recent and representative examples from the literature
highlighting which radiometal–chelator–antibody combinations
are the most successful for in vivo application.
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Affiliation(s)
- Marion Chomet
- Amsterdam UMC, Vrije Universiteit Amsterdam, Radiology & Nuclear Medicine, Cancer Center Amsterdam, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands
| | - Guus A M S van Dongen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Radiology & Nuclear Medicine, Cancer Center Amsterdam, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands
| | - Danielle J Vugts
- Amsterdam UMC, Vrije Universiteit Amsterdam, Radiology & Nuclear Medicine, Cancer Center Amsterdam, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands
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15
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Summers KL, Sarbisheh EK, Zimmerling A, Cotelesage JJH, Pickering IJ, George GN, Price EW. Structural Characterization of the Solution Chemistry of Zirconium(IV) Desferrioxamine: A Coordination Sphere Completed by Hydroxides. Inorg Chem 2020; 59:17443-17452. [PMID: 33183002 DOI: 10.1021/acs.inorgchem.0c02725] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Positron emission tomography (PET) using radiolabeled, monoclonal antibodies has become an effective, noninvasive method for tumor detection and is a critical component of targeted radionuclide therapy. Metal ion chelator and bacterial siderophore desferrioxamine (DFO) is the gold standard compound for incorporation of zirconium-89 in radiotracers for PET imaging because it is thought to form a stable chelate with [89Zr]Zr4+. However, DFO may not bind zirconium-89 tightly in vivo, with free zirconium-89 reportedly liberated into the bones of experimental mouse models. Although high bone uptake has not been observed to date in humans, this potential instability has been proposed to be related to the unsaturated coordination sphere of [89Zr]Zr-DFO, which is thought to consist of the 3 hydroxamate groups of DFO and 1 or 2 water molecules. In this study, we have used a combination of X-ray absorption spectroscopy and density functional theory (DFT) geometry optimization calculations to further probe the coordination chemistry of this complex in solution. We find the extended X-ray absorption fine structure (EXAFS) curve fitting of an aqueous solution of Zr(IV)-DFO to be consistent with an 8-coordinate Zr with oxygen ligands. DFT calculations suggest that the most energetically favorable Zr(IV) coordination environment in DFO likely consists of the 3 hydroxamate ligands from DFO, each with bidentate coordination, and 2 hydroxide ligands. Further EXAFS curve fitting provides additional support for this model. Therefore, we propose that the coordination sphere of Zr(IV)-DFO is most likely completed by 2 hydroxide ligands rather than 2 water molecules, forming Zr(DFO)(OH)2.
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Affiliation(s)
- Kelly L Summers
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Elaheh Khozeimeh Sarbisheh
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9
| | - Amanda Zimmerling
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9
| | - Julien J H Cotelesage
- Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Ingrid J Pickering
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Graham N George
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Eric W Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9
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16
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Sarbisheh EK, Salih AK, Raheem SJ, Lewis JS, Price EW. A High-Denticity Chelator Based on Desferrioxamine for Enhanced Coordination of Zirconium-89. Inorg Chem 2020; 59:11715-11727. [PMID: 32799484 DOI: 10.1021/acs.inorgchem.0c01629] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein we report a new high-denticity chelator based on the iron siderophore desferrioxamine (DFO). Our new chelator-DFO2-is acyclic and was designed and synthesized with the purpose of improving the coordination chemistry and radiolabeling performance with radioactive zirconium-89. The radionuclide zirconium-89 ([89Zr]Zr4+) has found wide use for positron emission tomography (PET) imaging when it is coupled with proteins, antibodies, and nanoparticles. DFO2 has a potential coordination number of 12, which uniquely positions this chelator for binding large, high-valent, and oxophilic metal ions. Following synthesis of the DFO2 chelator and the [natZr]Zr-(DFO2) complex we performed density functional theory calculations to study its coordination sphere, followed by zirconium-89 radiolabeling experiments for comparisons with the "gold standard" chelator DFO. DFO (CN 6) can coordinate with zirconium in a hexadentate fashion, leaving two open coordination sites where water is thought to coordinate (total CN 8). DFO2 (potential CN 12, dodecadentate) can saturate the coordination sphere of zirconium with four hydroxamate groups (CN 8), with no room left for water to directly coordinate, and only binds a single atom of zirconium per chelate. Following quantitative radiolabeling with zirconium-89, the preformed [89Zr]Zr-(DFO) and [89Zr]Zr-(DFO2) radiometal-chelate complexes were subjected to a battery of in vitro stability challenges, including human blood serum, apo-transferrin, serum albumin, iron, hydroxyapatite, and EDTA. One objective of these stability challenges was to determine if the increased denticity of DFO2 over that of DFO imparted improved complex stability, and another was to determine which of these assays is most relevant to perform with future chelators. In all of the assays DFO2 showed superior stability with zirconium-89, except for the iron challenge, where both DFO2 and DFO were identical. Substantial differences in stability were observed for human blood serum using a precipitation method of analysis, apo-transferrin, hydroxyapatite, and EDTA challenges. These results suggest that DFO2 is a promising next-generation scaffold for zirconium-89 chelators and holds promise for radiochemistry with even larger radionuclides, which we anticipate will expand the utility of DFO2 into theranostic applications.
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Affiliation(s)
- Elaheh Khozeimeh Sarbisheh
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Akam K Salih
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Shvan J Raheem
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Jason S Lewis
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States.,Radiochemistry and Molecular Imaging Probes Core, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States.,Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065, United States.,Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States.,Department of Radiology, Weill Cornell Medical College, New York, New York 10065, United States
| | - Eric W Price
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
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17
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Brandt M, Cowell J, Aulsebrook ML, Gasser G, Mindt TL. Radiolabelling of the octadentate chelators DFO* and oxoDFO* with zirconium-89 and gallium-68. J Biol Inorg Chem 2020; 25:789-796. [PMID: 32661784 DOI: 10.1007/s00775-020-01800-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/06/2020] [Indexed: 01/20/2023]
Abstract
In recent years, clinical imaging with zirconium-89 (89Zr)-labelled monoclonal antibodies (Ab) by positron emission tomography (immunoPET) has been gaining significant importance in nuclear medicine for the diagnosis of different types of cancer. For complexation of the radiometal 89Zr and its attachment to the Ab, chelating agents are required. To date, only the hexadentate chelator desferrioxamine (DFO) is applied in the clinic for this purpose. However, there is increasing preclinical evidence that the [89Zr]Zr-DFO complex is not sufficiently stable and partly releases the radiometal in vivo due to the incomplete coordination sphere of the metal. This leads to unfavourable unspecific uptake of the osteophilic radiometal in bones, hence decreasing the signal-to-noise-ratio and leading to an increased dose to the patient. In the past, several new chelators with denticities > 6 have been published, notably the octadentate DFO derivative DFO*. DFO*, however, shows limited water solubility, wherefore an oxygen containing analogue, termed oxoDFO*, was developed in 2017. However, no data on the suitability of oxoDFO* for radiolabelling with 89Zr has yet been reported. In this proof-of-concept study, we present the first radiolabelling results of the octadentate, water-soluble chelator oxoDFO*, as well as the in vitro stability of the resulting complex [89Zr]Zr-oxoDFO* in comparison to the analogous octadentate, but less water-soluble derivative DFO* and the current "standard" chelator DFO. In addition, the suitability of DFO* and oxoDFO* for radiolabeling with the short-lived PET metal gallium-68 is discussed. The water-soluble, octadentate chelator oxoDFO* provides stable complexes with the positron emitter Zirconium-89. The radiolabelling can be performed at room temperature and neutral pH and thus, oxoDFO* represents a promising chelator for applications in immunoPET.
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Affiliation(s)
- Marie Brandt
- Ludwig Boltzmann Institute Applied Diagnostics, General Hospital of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.,Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Joseph Cowell
- Laboratory for Inorganic Chemical Biology, Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, 75005, Paris, France
| | - Margaret L Aulsebrook
- Laboratory for Inorganic Chemical Biology, Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, 75005, Paris, France
| | - Gilles Gasser
- Laboratory for Inorganic Chemical Biology, Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, 75005, Paris, France.
| | - Thomas L Mindt
- Ludwig Boltzmann Institute Applied Diagnostics, General Hospital of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria. .,Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria. .,Department of Chemistry, Institute of Inorganic Chemistry, University of Vienna, Währinger Straße 42, 1090, Vienna, Austria.
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18
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Alnahwi A, Ait-Mohand S, Dumulon-Perreault V, Dory YL, Guérin B. Promising Performance of 4HMS, a New Zirconium-89 Octadendate Chelator. ACS OMEGA 2020; 5:10731-10739. [PMID: 32455192 PMCID: PMC7240819 DOI: 10.1021/acsomega.0c00207] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
Over the last decade, the interest in zirconium-89 (89Zr) as a positron-emitting radionuclide increased considerably because of its standardized production and its physical half-life (78.41 h), which matches the biological half-life of antibodies and its successful use in preclinical and clinical applications. So far, desferrioxamine (DFO), a commercially available chelator, has been mainly used as a bifunctional chelating system. However, there are some concerns regarding the in vivo stability of the [89Zr]Zr-DFO complex. In this study, we report the synthesis of an acyclic N-hydroxy-N-methyl succinamide-based chelator (4HMS) with 8 coordination sites and our first investigations into the use of this new chelator for 89Zr complexation. In vitro and in vivo comparative studies with [89Zr]Zr-4HMS and [89Zr]Zr-DFO are presented. The 4HMS chelator was synthesized in four steps starting with an excellent overall yield. Both chelators were quantitatively labeled with 89Zr within 5-10 min at pH 7 and room temperature; the molar activity of [89Zr]Zr-4HMS exceeded (>3 times) that of [89Zr]Zr-DFO. [89Zr]Zr-4HMS remained stable against transmetalation and transchelation and cleared from most tissues within 24 h. The kidney, liver, bone, and spleen uptakes were significantly low for this 89Zr-complex. Positron emission tomography images were in accordance with the results of the biodistribution in healthy mice. Based on DFT calculations, a rationale is provided for the high stability of 89Zr-4HMS. This makes 4HMS a promising chelator for future development of 89Zr-radiopharmaceuticals.
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Affiliation(s)
- Aiman
H. Alnahwi
- Department
of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health
Sciences, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Samia Ait-Mohand
- Department
of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health
Sciences, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Véronique Dumulon-Perreault
- Sherbrooke
Molecular Imaging Center (CIMS), CRCHUS, 3001, 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
| | - Yves L. Dory
- Laboratoire
de Synthèse Supramoléculaire. Department of Chemistry,
Institut de Pharmacologie, Université
de Sherbooke, 3001, 12e
Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
| | - Brigitte Guérin
- Department
of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health
Sciences, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Sherbrooke
Molecular Imaging Center (CIMS), CRCHUS, 3001, 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
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19
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Guillou A, Earley DF, Holland JP. Light‐Activated Protein Conjugation and
89
Zr‐Radiolabelling with Water‐Soluble Desferrioxamine Derivatives. Chemistry 2020; 26:7185-7189. [DOI: 10.1002/chem.202001755] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Indexed: 01/03/2023]
Affiliation(s)
- Amaury Guillou
- University of ZurichDepartment of Chemistry Winterthurerstrasse 190 Zurich 8057 Switzerland
| | - Daniel F. Earley
- University of ZurichDepartment of Chemistry Winterthurerstrasse 190 Zurich 8057 Switzerland
| | - Jason P. Holland
- University of ZurichDepartment of Chemistry Winterthurerstrasse 190 Zurich 8057 Switzerland
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20
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Abstract
The thermodynamic stability of a metal-ligand complex, as measured by the formation constant (log β), is one of the most important parameters that determines metal ion selectivity and potential applications in, for example, radiopharmaceutical science. The stable coordination chemistry of radioactive 89Zr4+ in an aqueous environment is of paramount importance when developing positron-emitting radiotracers based on proteins (usually antibodies) for use with positron emission tomography. Desferrioxamine B (DFO) remains the chelate of choice for clinical applications of 89Zr-labeled proteins, but the coordination of DFO to Zr4+ ions is suboptimal. Many alternative ligands have been reported, but the challenges in measuring very high log β values with metal ions such as Zr4+ that tend to hydrolyze mean that accurate thermodynamic data are scarce. In this work, density functional theory (DFT) calculations were used to predict the reaction energetics for metal ion complexation. Computed values of pseudoformation constants (log β') are correlated with experimental data and showed an excellent linear relationship (R2 = 0.97). The model was then used to estimate the absolute and relative formation constants of 23 different Zr4+ complexes using a total of 17 different ligands, including many of the alternative bifunctional chelates that have been reported recently for use in 89Zr4+ radiochemistry. In addition, detailed computational studies were performed on the geometric isomerism and hydration state of Zr-desferrioxamine. Collectively, the results offer new insights into Zr4+ coordination chemistry that will help guide the synthesis of future ligands. The computational model developed here is straightforward and reproducible and can be readily applied in the design of other metal coordination compounds.
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Affiliation(s)
- Jason P Holland
- University of Zurich , Department of Chemistry , Winterthurerstrasse 190 , CH-8057 Zurich , Switzerland
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21
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Connah L, Angelovski G. Solid phase synthesis in the development of magnetic resonance imaging probes. Org Chem Front 2020. [DOI: 10.1039/d0qo00921k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We review the use of the solid phase synthesis methodology for the preparation of diverse and potent MRI probes.
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Affiliation(s)
- Liam Connah
- MR Neuroimaging Agents
- Max Planck Institute for Biological Cybernetics
- Tuebingen
- Germany
| | - Goran Angelovski
- MR Neuroimaging Agents
- Max Planck Institute for Biological Cybernetics
- Tuebingen
- Germany
- Laboratory of Molecular and Cellular Neuroimaging
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22
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Buchwalder C, Jaraquemada-Peláez MDG, Rousseau J, Merkens H, Rodríguez-Rodríguez C, Orvig C, Bénard F, Schaffer P, Saatchi K, Häfeli UO. Evaluation of the Tetrakis(3-Hydroxy-4-Pyridinone) Ligand THPN with Zirconium(IV): Thermodynamic Solution Studies, Bifunctionalization, and in Vivo Assessment of Macromolecular 89Zr-THPN-Conjugates. Inorg Chem 2019; 58:14667-14681. [DOI: 10.1021/acs.inorgchem.9b02350] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christian Buchwalder
- University of British Columbia, Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | | | - Julie Rousseau
- BC Cancer Agency, Department of Functional Imaging, 600 West 10th Avenue, Vancouver, BC V5Z 4E6, Canada
| | - Helen Merkens
- BC Cancer Agency, Department of Functional Imaging, 600 West 10th Avenue, Vancouver, BC V5Z 4E6, Canada
| | - Cristina Rodríguez-Rodríguez
- University of British Columbia, Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
- University of British Columbia, Department of Physics & Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
| | - Chris Orvig
- Medicinal Inorganic Chemistry Group, University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - François Bénard
- BC Cancer Agency, Department of Functional Imaging, 600 West 10th Avenue, Vancouver, BC V5Z 4E6, Canada
| | - Paul Schaffer
- TRIUMF, Life Sciences Division, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
| | - Katayoun Saatchi
- University of British Columbia, Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Urs O. Häfeli
- University of British Columbia, Faculty of Pharmaceutical Sciences, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
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23
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Zirconium-89 radio-nanochemistry and its applications towards the bioimaging of prostate cancer. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.119041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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24
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Analogues of desferrioxamine B (DFOB) with new properties and new functions generated using precursor-directed biosynthesis. Biometals 2019; 32:395-408. [PMID: 30701380 DOI: 10.1007/s10534-019-00175-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 01/21/2019] [Indexed: 10/27/2022]
Abstract
Desferrioxamine B (DFOB) is a siderophore native to Streptomyces pilosus biosynthesised by the DesABCD enzyme cluster as a high affinity Fe(III) chelator. Although DFOB has a long clinical history for the treatment of chronic iron overload, limitations encourage the development of new analogues. This review describes a recent body of work that has used precursor-directed biosynthesis (PDB) to access new DFOB analogues. PDB exploits the native biosynthetic machinery of a producing organism in culture medium augmented with non-native substrates that compete against native substrates during metabolite assembly. The method allows access to analogues of natural products using benign methods, compared to multistep organic synthesis. The disadvantages of PDB are the production of metabolites in low yield and the need to purify complex mixtures. Streptomyces pilosus medium was supplemented with different types of non-native diamine substrates to compete against native 1,5-diaminopentane to generate DFOB analogues containing alkene bonds, fluorine atoms, ether or thioether functional groups, or a disulfide bond. All analogues retained function as Fe(III) chelators and have properties that could broaden the utility of DFOB. These PDB studies have also added knowledge to the understanding of DFOB biosynthesis.
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25
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Bhatt NB, Pandya DN, Rideout-Danner S, Gage HD, Marini FC, Wadas TJ. A comprehensively revised strategy that improves the specific activity and long-term stability of clinically relevant 89Zr-immuno-PET agents. Dalton Trans 2018; 47:13214-13221. [PMID: 30178793 PMCID: PMC6192516 DOI: 10.1039/c8dt01841c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Zirconium-89 is currently being used in numerous clinical trials involving monoclonal antibodies and positron emission tomography. This report describes a revised strategy that reduces preparation time while increasing the specific activity of clinically relevant immuno-PET agents. Additionally, it demonstrates that n-acetyl-l-cysteine acts as a superior radioprotective agent that improves long-term stability without compromising antigen affinity in vivo.
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Affiliation(s)
- Nikunj B Bhatt
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | - Darpan N Pandya
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | | | - Howard D Gage
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Frank C Marini
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA. and Wake Forest Institute of Regenerative Medicine, Winston-Salem, NC 27157, USA
| | - Thaddeus J Wadas
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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26
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Brandt M, Cardinale J, Aulsebrook ML, Gasser G, Mindt TL. An Overview of PET Radiochemistry, Part 2: Radiometals. J Nucl Med 2018; 59:1500-1506. [DOI: 10.2967/jnumed.117.190801] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/03/2018] [Indexed: 12/13/2022] Open
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27
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Abstract
The interest in zirconium-89 (89Zr) as a positron-emitting radionuclide has grown considerably over the last decade due to its standardized production, long half-life of 78.2 h, favorable decay characteristics for positron emission tomography (PET) imaging and its successful use in a variety of clinical and preclinical applications. However, to be utilized effectively in PET applications it must be stably bound to a targeting ligand, and the most successfully used 89Zr chelator is desferrioxamine B (DFO), which is commercially available as the iron chelator Desferal®. Despite the prevalence of DFO in 89Zr-immuno-PET applications, the development of new ligands for this radiometal is an active area of research. This review focuses on recent advances in zirconium-89 chelation chemistry and will highlight the rapidly expanding ligand classes that are under investigation as DFO alternatives.
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Affiliation(s)
- Nikunj B Bhatt
- Department of Cancer Biology, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA.
| | - Darpan N Pandya
- Department of Cancer Biology, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA.
| | - Thaddeus J Wadas
- Department of Cancer Biology, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA.
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