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Price T, Wagner L, Rosecker V, Havlíčková J, Prior TJ, Kubíček V, Hermann P, Stasiuk GJ. Inorganic Chemistry of the Tripodal Picolinate Ligand Tpaa with Gallium(III) and Radiolabeling with Gallium-68. Inorg Chem 2023; 62:20769-20776. [PMID: 37793007 PMCID: PMC10731648 DOI: 10.1021/acs.inorgchem.3c02459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Indexed: 10/06/2023]
Abstract
We report here the improved synthesis of the tripodal picolinate chelator Tpaa, with an overall yield of 41% over five steps, in comparison to the previously reported 6% yield. Tpaa was investigated for its coordination chemistry with Ga(III) and radiolabeling properties with gallium-68 (68Ga). The obtained crystal structure for [Ga(Tpaa)] shows that the three picolinate arms coordinate to the Ga(III) ion, fully occupying the octahedral coordination geometry. This is supported by 1H NMR which shows that the three arms are symmetrical when coordinated to Ga(III). Assessment of the thermodynamic stability through potentiometry gives log KGa-Tpaa = 21.32, with a single species being produced across the range of pH 3.5-7.5. Tpaa achieved >99% radiochemical conversion with 68Ga under mild conditions ([Tpaa] = 6.6 μM, pH 7.4, 37 °C) with a molar activity of 3.1 GBq μmol-1. The resulting complex, [68Ga][Ga(Tpaa)], showed improved stability over the previously reported [68Ga][Ga(Dpaa)(H2O)] in a serum challenge, with 32% of [68Ga][Ga(Tpaa)] remaining intact after 30 min of incubation with fetal bovine serum.
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Affiliation(s)
- Thomas
W. Price
- Department
of Imaging Chemistry and Biology, School of Biomedical Engineering
and Imaging Sciences, King’s College
London, London SE1 7EH, United
Kingdom
| | - Laurène Wagner
- Department
of Imaging Chemistry and Biology, School of Biomedical Engineering
and Imaging Sciences, King’s College
London, London SE1 7EH, United
Kingdom
| | - Veronika Rosecker
- Department
of Imaging Chemistry and Biology, School of Biomedical Engineering
and Imaging Sciences, King’s College
London, London SE1 7EH, United
Kingdom
| | - Jana Havlíčková
- Department
of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic
| | - Timothy J. Prior
- Chemistry,
School of Natural Sciences, University of
Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
| | - Vojtěch Kubíček
- Department
of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic
| | - Petr Hermann
- Department
of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic
| | - Graeme J. Stasiuk
- Department
of Imaging Chemistry and Biology, School of Biomedical Engineering
and Imaging Sciences, King’s College
London, London SE1 7EH, United
Kingdom
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Wang Y, Yuan H, Tang S, Liu Y, Cai P, Liu N, Chen Y, Zhou Z. The effects of novel macrocyclic chelates on the targeting properties of the 68Ga-labeled Gastrin releasing peptide receptor antagonist RM2. EJNMMI Res 2023; 13:56. [PMID: 37285007 DOI: 10.1186/s13550-023-01005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/01/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND The gastrin-releasing peptide receptor (GRPr) is a molecular target for the visualization of prostate cancer. Bombesin (BN) analogs are short peptides with a high affinity for GRPr. RM2 is a bombesin-based antagonist. It has been demonstrated that RM2 have superior in vivo biodistribution and targeting properties than high-affinity receptor agonists. This study developed new RM2-like antagonists by introducing the novel bifunctional chelators AAZTA5 and DATA5m to RM2. RESULTS The effects of different macrocyclic chelating groups on drug targeting properties and the possibility of preparing 68Ga-radiopharmaceuticals in a kit-based protocol were investigated using 68Ga-labeled entities. Both new RM2 variants were labelled with 68Ga3+ resulting in high yields, stability, and low molarity of the ligand. DATA5m-RM2 and AAZTA5-RM2 incorporated 68Ga3+ nearly quantitatively at room temperature within 3-5 min, and the labelling yield for 68Ga-DOTA-RM2 was approximately 10% under the same conditions. 68Ga-AAZTA5-RM2 showed stronger hydrophilicity according to partition coefficient. Although the maximal cellular uptake values of the three compounds were similar, 68Ga-AAZTA5-RM2 and 68Ga-DATA5m-RM2 peaked more rapidly. Biodistribution studies showed high and specific tumor uptake, with a maximum of 9.12 ± 0.81 percentage injected activity per gram of tissue (%ID/g) for 68Ga-DATA5m-RM2 and 7.82 ± 0.61%ID/g for 68Ga-AAZTA5-RM2 at 30 min after injection. CONCLUSIONS The conditions for complexation of DATA5m-RM2 and AAZTA5-RM2 with gallium-68 are milder, faster and require less amount of precursors than DOTA-RM2. Chelators had an evident influence on the pharmacokinetics and targeting properties of 68Ga-X-RM2 derivatives. Positively charged 68Ga-DATA5m-RM2 provided a high tumor uptake, high image contrast and good capability of targeting GRPr.
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Affiliation(s)
- Yinwen Wang
- The Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Hongmei Yuan
- The Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Sufan Tang
- The Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Yang Liu
- The Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Ping Cai
- The Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Nan Liu
- Department of Nuclear Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Yue Chen
- The Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China.
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
| | - Zhijun Zhou
- The Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China.
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
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[111In]In/[177Lu]Lu-AAZTA5-LM4 SST2R-Antagonists in Cancer Theranostics: From Preclinical Testing to First Patient Results. Pharmaceutics 2023; 15:pharmaceutics15030776. [PMID: 36986637 PMCID: PMC10053881 DOI: 10.3390/pharmaceutics15030776] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
Aiming to expand the application of the SST2R-antagonist LM4 (DPhe-c[DCys-4Pal-DAph(Cbm)-Lys-Thr-Cys]-DTyr-NH2) beyond [68Ga]Ga-DATA5m-LM4 PET/CT (DATA5m, (6-pentanoic acid)-6-(amino)methy-1,4-diazepinetriacetate), we now introduce AAZTA5-LM4 (AAZTA5, 1,4-bis(carboxymethyl)-6-[bis(carboxymethyl)]amino-6-[pentanoic-acid]perhydro-1,4-diazepine), allowing for the convenient coordination of trivalent radiometals of clinical interest, such as In-111 (for SPECT/CT) or Lu-177 (for radionuclide therapy). After labeling, the preclinical profiles of [111In]In-AAZTA5-LM4 and [177Lu]Lu-AAZTA5-LM4 were compared in HEK293-SST2R cells and double HEK293-SST2R/wtHEK293 tumor-bearing mice using [111In]In-DOTA-LM3 and [177Lu]Lu-DOTA-LM3 as references. The biodistribution of [177Lu]Lu-AAZTA5-LM4 was additionally studied for the first time in a NET patient. Both [111In]In-AAZTA5-LM4 and [177Lu]Lu-AAZTA5-LM4 displayed high and selective targeting of the HEK293-SST2R tumors in mice and fast background clearance via the kidneys and the urinary system. This pattern was reproduced for [177Lu]Lu-AAZTA5-LM4 in the patient according to SPECT/CT results in a monitoring time span of 4–72 h pi. In view of the above, we may conclude that [177Lu]Lu-AAZTA5-LM4 shows promise as a therapeutic radiopharmaceutical candidate for SST2R-expressing human NETs, based on previous [68Ga]Ga-DATA5m-LM4 PET/CT, but further studies are needed to fully assess its clinical value. Furthermore, [111In]In-AAZTA5-LM4 SPECT/CT may represent a legitimate alternative diagnostic option in cases where PET/CT is not available.
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Modern Developments in Bifunctional Chelator Design for Gallium Radiopharmaceuticals. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010203. [PMID: 36615397 PMCID: PMC9822085 DOI: 10.3390/molecules28010203] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022]
Abstract
The positron-emitting radionuclide gallium-68 has become increasingly utilised in both preclinical and clinical settings with positron emission tomography (PET). The synthesis of radiochemically pure gallium-68 radiopharmaceuticals relies on careful consideration of the coordination chemistry. The short half-life of 68 min necessitates rapid quantitative radiolabelling (≤10 min). Desirable radiolabelling conditions include near-neutral pH, ambient temperatures, and low chelator concentrations to achieve the desired apparent molar activity. This review presents a broad overview of the requirements of an efficient bifunctional chelator in relation to the aqueous coordination chemistry of gallium. Developments in bifunctional chelator design and application are then presented and grouped according to eight categories of bifunctional chelator: the macrocyclic chelators DOTA and TACN; the acyclic HBED, pyridinecarboxylates, siderophores, tris(hydroxypyridinones), and DTPA; and the mesocyclic diazepines.
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Kanellopoulos P, Nock BA, Greifenstein L, Baum RP, Roesch F, Maina T. [ 68Ga]Ga-DATA 5m-LM4, a PET Radiotracer in the Diagnosis of SST 2R-Positive Tumors: Preclinical and First Clinical Results. Int J Mol Sci 2022; 23:ijms232314590. [PMID: 36498918 PMCID: PMC9740503 DOI: 10.3390/ijms232314590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022] Open
Abstract
Radiolabeled somatostatin subtype 2 receptor (SST2R)-antagonists have shown advantageous profiles for cancer theranostics compared with agonists. On the other hand, the newly introduced hybrid chelator (6-pentanoic acid)-6-(amino)methyl-1,4-diazepinetriacetate (DATA5m) rapidly binds Ga-68 (t1/2: 67.7 min) at much lower temperature, thus allowing for quick access to "ready-for-injection" [68Ga]Ga-tracers in hospitals. We herein introduce [68Ga]Ga-DATA5m-LM4 for PET/CT imaging of SST2R-positive human tumors. LM4 was obtained by 4Pal3/Tyr3-substitution in the known SST2R antagonist LM3 (H-DPhe-c[DCys-Tyr-DAph(Cbm)-Lys-Thr-Cys]-DTyr-NH2) and DATA5m was coupled at the N-terminus for labeling with radiogallium (Ga-67/68). [67Ga]Ga-DATA5m-LM4 was evaluated in HEK293-SST2R cells and mice models in a head-to-head comparison with [67Ga]Ga-DOTA-LM3. Clinical grade [68Ga]Ga-DATA5m-LM4 was prepared and injected in a neuroendocrine tumor (NET) patient for PET/CT imaging. DATA5m-LM4 displayed high SST2R binding affinity. [67Ga]Ga-DATA5m-LM4 showed markedly higher uptake in HEK293-SST2R cells versus [67Ga]Ga-DOTA-LM3 and was stable in vivo. In HEK293-SST2R xenograft-bearing mice, it achieved longer tumor retention and less kidney uptake than [67Ga]Ga-DOTA-LM3. [68Ga]Ga-DATA5m-LM4 accurately visualized tumor lesions with high contrast on PET/CT. In short, [68Ga]Ga-DATA5m-LM4 has shown excellent prospects for the PET/CT diagnosis of SST2R-positive tumors, further highlighting the benefits of Ga-68 labeling in a hospital environment via the DATA5m-chelator route.
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Affiliation(s)
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, GR-15310 Athens, Greece
| | - Lukas Greifenstein
- CURANOSTICUM Wiesbaden-Frankfurt, DKD Helios Klinik, D-65191 Wiesbaden, Germany
| | - Richard P. Baum
- CURANOSTICUM Wiesbaden-Frankfurt, DKD Helios Klinik, D-65191 Wiesbaden, Germany
| | - Frank Roesch
- Department Chemie, Standort TRIGA, Johannes Gutenberg-Universität Mainz, D-55126 Mainz, Germany
| | - Theodosia Maina
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, GR-15310 Athens, Greece
- Correspondence: ; Tel.: +30-210-650-3908 (ext. 3891)
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Price TW, Renard I, Prior TJ, Kubíček V, Benoit DM, Archibald SJ, Seymour AM, Hermann P, Stasiuk GJ. Bn2DT3A, a Chelator for 68Ga Positron Emission Tomography: Hydroxide Coordination Increases Biological Stability of [ 68Ga][Ga(Bn 2DT3A)(OH)] . Inorg Chem 2022; 61:17059-17067. [PMID: 36251390 DOI: 10.1021/acs.inorgchem.2c01992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chelator Bn2DT3A was used to produce a novel 68Ga complex for positron emission tomography (PET). Unusually, this system is stabilized by a coordinated hydroxide in aqueous solutions above pH 5, which confers sufficient stability for it to be used for PET. Bn2DT3A complexes Ga3+ in a hexadentate manner, forming a mer-mer complex with log K([Ga(Bn2DT3A)]) = 18.25. Above pH 5, the hydroxide ion coordinates the Ga3+ ion following dissociation of a coordinated amine. Bn2DT3A radiolabeling displayed a pH-dependent speciation, with [68Ga][Ga(Bn2DT3A)(OH)]- being formed above pH 5 and efficiently radiolabeled at pH 7.4. Surprisingly, [68Ga][Ga(Bn2DT3A)(OH)]- was found to show an increased stability in vitro (for over 2 h in fetal bovine serum) compared to [68Ga][Ga(Bn2DT3A)]. The biodistribution of [68Ga][Ga(Bn2DT3A)(OH)]- in healthy rats showed rapid clearance and excretion via the kidneys, with no uptake seen in the lungs or bones.
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Affiliation(s)
- Thomas W Price
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, London SE1 7EH, U.K.,Department of Biomedical Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, U.K.,Positron Emission Tomography Research Center, University of Hull, Cottingham Road, Hull HU6 7RX, U.K
| | - Isaline Renard
- Department of Biomedical Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, U.K.,Positron Emission Tomography Research Center, University of Hull, Cottingham Road, Hull HU6 7RX, U.K
| | - Timothy J Prior
- Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX, U.K
| | - Vojtěch Kubíček
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, Prague 2, Czech Republic
| | - David M Benoit
- E.A. Milne Centre for Astrophysics, Department of Physics and Mathematics, University of Hull, Cottingham Road, Hull HU6 7RX, U.K
| | - Stephen J Archibald
- Department of Biomedical Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, U.K.,Positron Emission Tomography Research Center, University of Hull, Cottingham Road, Hull HU6 7RX, U.K
| | - Anne-Marie Seymour
- Department of Biomedical Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, U.K
| | - Petr Hermann
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, Prague 2, Czech Republic
| | - Graeme J Stasiuk
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, London SE1 7EH, U.K
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Fersing C, Masurier N, Rubira L, Deshayes E, Lisowski V. AAZTA-Derived Chelators for the Design of Innovative Radiopharmaceuticals with Theranostic Applications. Pharmaceuticals (Basel) 2022; 15:234. [PMID: 35215346 PMCID: PMC8879111 DOI: 10.3390/ph15020234] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/12/2022] [Accepted: 02/14/2022] [Indexed: 02/06/2023] Open
Abstract
With the development of 68Ga and 177Lu radiochemistry, theranostic approaches in modern nuclear medicine enabling patient-centered personalized medicine applications have been growing in the last decade. In conjunction with the search for new relevant molecular targets, the design of innovative chelating agents to easily form stable complexes with various radiometals for theranostic applications has gained evident momentum. Initially conceived for magnetic resonance imaging applications, the chelating agent AAZTA features a mesocyclic seven-membered diazepane ring, conferring some of the properties of both acyclic and macrocyclic chelating agents. Described in the early 2000s, AAZTA and its derivatives exhibited interesting properties once complexed with metals and radiometals, combining a fast kinetic of formation with a slow kinetic of dissociation. Importantly, the extremely short coordination reaction times allowed by AAZTA derivatives were particularly suitable for short half-life radioelements (i.e., 68Ga). In view of these particular characteristics, the scope of this review is to provide a survey on the design, synthesis, and applications in the nuclear medicine/radiopharmacy field of AAZTA-derived chelators.
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Affiliation(s)
- Cyril Fersing
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34298 Montpellier, France; (L.R.); (E.D.)
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France; (N.M.); (V.L.)
| | - Nicolas Masurier
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France; (N.M.); (V.L.)
| | - Léa Rubira
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34298 Montpellier, France; (L.R.); (E.D.)
| | - Emmanuel Deshayes
- Nuclear Medicine Department, Institut Régional du Cancer de Montpellier (ICM), University Montpellier, 34298 Montpellier, France; (L.R.); (E.D.)
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, Institut Régional du Cancer de Montpellier (ICM), University of Montpellier, 34298 Montpellier, France
| | - Vincent Lisowski
- IBMM, University Montpellier, CNRS, ENSCM, 34293 Montpellier, France; (N.M.); (V.L.)
- Department of Pharmacy, Lapeyronie Hospital, CHU Montpellier, 191 Av. du Doyen Gaston Giraud, 34295 Montpellier, France
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Lepareur N. Cold Kit Labeling: The Future of 68Ga Radiopharmaceuticals? Front Med (Lausanne) 2022; 9:812050. [PMID: 35223907 PMCID: PMC8869247 DOI: 10.3389/fmed.2022.812050] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/07/2022] [Indexed: 12/11/2022] Open
Abstract
Over the last couple of decades, gallium-68 (68Ga) has gained a formidable interest for PET molecular imaging of various conditions, from cancer to infection, through cardiac pathologies or neuropathies. It has gained routine use, with successful radiopharmaceuticals such as somatostatin analogs ([68Ga]Ga-DOTATOC and [68Ga]GaDOTATATE) for neuroendocrine tumors, and PSMA ligands for prostate cancer. It represents a major clinical impact, particularly in the context of theranostics, coupled with their 177Lu-labeled counterparts. Beside those, a bunch of new 68Ga-labeled molecules are in the preclinical and clinical pipelines, with some of them showing great promise for patient care. Increasing clinical demand and regulatory issues have led to the development of automated procedures for the production of 68Ga radiopharmaceuticals. However, the widespread use of these radiopharmaceuticals may rely on simple and efficient radiolabeling methods, undemanding in terms of equipment and infrastructure. To make them technically and economically accessible to the medical community and its patients, it appears mandatory to develop a procedure similar to the well-established kit-based 99mTc chemistry. Already available commercial kits for the production of 68Ga radiopharmaceuticals have demonstrated the feasibility of using such an approach, thus paving the way for more kit-based 68Ga radiopharmaceuticals to be developed. This article discusses the development of 68Ga cold kit radiopharmacy, including technical issues, and regulatory aspects.
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Affiliation(s)
- Nicolas Lepareur
- Comprehensive Cancer Center Eugène Marquis, Rennes, France
- Univ Rennes, Inrae, Inserm, Institut NUMECAN (Nutrition, Métabolismes et Cancer), UMR_A 1341, UMR_S 1241, Rennes, France
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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] [MESH Headings] [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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Lahnif H, Grus T, Pektor S, Greifenstein L, Schreckenberger M, Rösch F. Hybrid Chelator-Based PSMA Radiopharmaceuticals: Translational Approach. Molecules 2021; 26:molecules26216332. [PMID: 34770742 PMCID: PMC8588462 DOI: 10.3390/molecules26216332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 01/22/2023] Open
Abstract
(1) Background: Prostate-specific membrane antigen (PSMA) has been extensively studied in the last decade. It became a promising biological target in the diagnosis and therapy of PSMA-expressing cancer diseases. Although there are several radiolabeled PSMA inhibitors available, the search for new compounds with improved pharmacokinetic properties and simplified synthesis is still ongoing. In this study, we developed PSMA ligands with two different hybrid chelators and a modified linker. Both compounds have displayed a promising pharmacokinetic profile. (2) Methods: DATA5m.SA.KuE and AAZTA5.SA.KuE were synthesized. DATA5m.SA.KuE was labeled with gallium-68 and radiochemical yields of various amounts of precursor at different temperatures were determined. Complex stability in phosphate-buffered saline (PBS) and human serum (HS) was examined at 37 °C. Binding affinity and internalization ratio were determined in in vitro assays using PSMA-positive LNCaP cells. Tumor accumulation and biodistribution were evaluated in vivo and ex vivo using an LNCaP Balb/c nude mouse model. All experiments were conducted with PSMA-11 as reference. (3) Results: DATA5m.SA.KuE was synthesized successfully. AAZTA5.SA.KuE was synthesized and labeled according to the literature. Radiolabeling of DATA5m.SA.KuE with gallium-68 was performed in ammonium acetate buffer (1 M, pH 5.5). High radiochemical yields (>98%) were obtained with 5 nmol at 70 °C, 15 nmol at 50 °C, and 60 nmol (50 µg) at room temperature. [68Ga]Ga-DATA5m.SA.KuE was stable in human serum as well as in PBS after 120 min. PSMA binding affinities of AAZTA5.SA.KuE and DATA5m.SA.KuE were in the nanomolar range. PSMA-specific internalization ratio was comparable to PSMA-11. In vivo and ex vivo studies of [177Lu]Lu-AAZTA5.SA.KuE, [44Sc]Sc-AAZTA5.SA.KuE and [68Ga]Ga-DATA5m.SA.KuE displayed specific accumulation in the tumor along with fast clearance and reduced off-target uptake. (4) Conclusions: Both KuE-conjugates showed promising properties especially in vivo allowing for translational theranostic use.
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Affiliation(s)
- Hanane Lahnif
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
| | - Tilmann Grus
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
| | - Stefanie Pektor
- Department of Nuclear Medicine, University Medical Center Mainz, 55131 Mainz, Germany; (S.P.); (M.S.)
| | - Lukas Greifenstein
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
- Curanosticum Wiesbaden–Frankfurt, 65191 Wiesbaden, Germany
| | - Mathias Schreckenberger
- Department of Nuclear Medicine, University Medical Center Mainz, 55131 Mainz, Germany; (S.P.); (M.S.)
| | - Frank Rösch
- Department of Chemistry—TRIGA Site, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (H.L.); (T.G.); (L.G.)
- Correspondence: ; Tel.: +49-6131-39-25302
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Travagin F, Lattuada L, Giovenzana GB. AAZTA: The rise of mesocyclic chelating agents for metal coordination in medicine. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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12
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Floresta G, Keeling GP, Memdouh S, Meszaros LK, de Rosales RTM, Abbate V. NHS-Functionalized THP Derivative for Efficient Synthesis of Kit-Based Precursors for 68Ga Labeled PET Probes. Biomedicines 2021; 9:367. [PMID: 33915871 PMCID: PMC8066796 DOI: 10.3390/biomedicines9040367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/06/2021] [Accepted: 03/30/2021] [Indexed: 12/28/2022] Open
Abstract
Hexadentate tris(3,4-hydroxypyridinone) ligands (THP) complex Fe3+ at very low iron concentrations and their high affinities for oxophilic trivalent metal ions have led to their development for new applications as bifunctional chelators for the radiometal gallium-68 (68Ga). THP-peptide bioconjugates rapidly and quantitatively complex 68Ga at room temperature, neutral pH, and micromolar ligand concentrations, making them amenable to kit-based radiosynthesis of 68Ga PET radiopharmaceuticals. With the aim to produce an N-hydroxysuccinimide-(NHS)-THP reagent for kit-based 68Ga-labeling and PET imaging, THP-derivatives were designed and synthesized to exploit the advantages of NHS chemistry for coupling with peptides, proteins, and antibodies. The more stable five-carbon atoms linker product was selected for a proof-of-concept conjugation and radiolabeling study with an anti-programmed death ligand 1 (PD-L1) camelid single domain antibody (sdAb) under mild conditions and further evaluated for site-specific amide bond formation with a synthesized glucagon-like peptide-1 (GLP-1) targeting peptide using solid-phase synthesis. The obtained THP-GLP-1 conjugate was tested for its 68Ga chelating ability, demonstrating to be a promising candidate for the detection and monitoring of GLP-1 aberrant malignancies. The obtained sdAb-THP conjugate was radiolabeled with 68Ga under mild conditions, providing sufficient labeling yields after 5 min, demonstrating that the novel NHS-THP bifunctional chelator can be widely used to easily conjugate the THP moiety to different targeting molecules (e.g., antibodies, anticalins, or peptides) under mild conditions, paving the way to the synthesis of different imaging probes with all the advantages of THP radiochemistry.
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Affiliation(s)
- Giuseppe Floresta
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London SE1 9NH, UK; (G.F.); (S.M.)
| | - George P. Keeling
- School of Biomedical Engineering & Imaging Sciences, King’s College London, St Thomas’ Hospital, London SE1 7EH, UK; (G.P.K.); (L.K.M.); (R.T.M.d.R.)
| | - Siham Memdouh
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London SE1 9NH, UK; (G.F.); (S.M.)
| | - Levente K. Meszaros
- School of Biomedical Engineering & Imaging Sciences, King’s College London, St Thomas’ Hospital, London SE1 7EH, UK; (G.P.K.); (L.K.M.); (R.T.M.d.R.)
- NanoMab Technology (UK) Ltd., 720 Centennial Court, Centennial Park, Elstree, Hertfordshire WD6 3SY, UK
| | - Rafael T. M. de Rosales
- School of Biomedical Engineering & Imaging Sciences, King’s College London, St Thomas’ Hospital, London SE1 7EH, UK; (G.P.K.); (L.K.M.); (R.T.M.d.R.)
| | - Vincenzo Abbate
- Department of Analytical, Environmental and Forensic Sciences, King’s College London, London SE1 9NH, UK; (G.F.); (S.M.)
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Satpati D. Recent Breakthrough in 68Ga-Radiopharmaceuticals Cold Kits for Convenient PET Radiopharmacy. Bioconjug Chem 2021; 32:430-447. [PMID: 33630583 DOI: 10.1021/acs.bioconjchem.1c00010] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
68Ga-PET has emerged as an important diagnostic tool for precise detection and monitoring of oncological situations. Availability, cost, and radiosynthesis procedure are determining steps for success of a radioisotope/radiopharmaceutical in nuclear medicine. Availability of 68Ga from a 68Ge/68Ga generator containing a long-lived parent radioisotope (68Ge: t1/2 = 271 days) and an inexpensive, simplified production of 68Ga-radiopharmaceuticals through kit methodology has allowed smooth accommodation of 68Ga-PET in clinics. The uncomplicated formulation of 68Ga-radiopharmaceuticals from a lyophilized, cold kit is an impending breakthrough in clinical PET. The huge success of 68Ga in neuroendocrine tumor and prostate cancer imaging along with the regulatory approval of respective cold kits has opened a pathway for development of kits for other evolving radiotracers. There is a definite scope for increased participation of commercial manufacturers and distributors of cold kits to spread the potential of 68Ga worldwide across all the geographical locations and satellite centers.
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Affiliation(s)
- Drishty Satpati
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai-400085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, India
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Sinnes JP, Bauder-Wüst U, Schäfer M, Moon ES, Kopka K, Rösch F. 68Ga, 44Sc and 177Lu-labeled AAZTA 5-PSMA-617: synthesis, radiolabeling, stability and cell binding compared to DOTA-PSMA-617 analogues. EJNMMI Radiopharm Chem 2020; 5:28. [PMID: 33242189 PMCID: PMC7691401 DOI: 10.1186/s41181-020-00107-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/19/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The AAZTA chelator and in particular its bifunctional derivative AAZTA5 was recently investigated to demonstrate unique capabilities to complex diagnostic and therapeutic trivalent radiometals under mild conditions. This study presents a comparison of 68Ga, 44Sc and 177Lu-labeled AAZTA5-PSMA-617 with DOTA-PSMA-617 analogues. We evaluated the radiolabeling characteristics, in vitro stability of the radiolabeled compounds and evaluated their binding affinity and internalization behavior on LNCaP tumor cells in direct comparison to the radiolabeled DOTA-conjugated PSMA-617 analogs. RESULTS AAZTA5 was synthesized in a five-step synthesis and coupled to the PSMA-617 backbone on solid phase. Radiochemical evaluation of AAZTA5-PSMA-617 with 68Ga, 44Sc and 177Lu achieved quantitative radiolabeling of > 99% after less than 5 min at room temperature. Stabilities against human serum, PBS buffer and EDTA and DTPA solutions were analyzed. While there was a small degradation of the 68Ga complex over 2 h in human serum, PBS and EDTA/DTPA, the 44Sc and 177Lu complexes were stable at 2 h and remained stable over 8 h and 1 day. For all three compounds, i.e. [natGa]Ga-AAZTA5-PSMA-617, [natSc]Sc-AAZTA5-PSMA-617 and [natLu]Lu-AAZTA5-PSMA-617, in vitro studies on PSMA-positive LNCaP cells were performed in direct comparison to radiolabeled DOTA-PSMA-617 yielding the corresponding inhibition constants (Ki). Ki values were in the range of 8-31 nM values which correspond with those of [natGa]Ga-DOTA-PSMA-617, [natSc]Sc-DOTA-PSMA-617 and [natLu]Lu-DOTA-PSMA-617, i.e. 5-7 nM, respectively. Internalization studies demonstrated cellular membrane to internalization ratios for the radiolabeled 68Ga, 44Sc and 177Lu-AAZTA5-PSMA-617 tracers (13-20%IA/106 cells) in the same range as the ones of the three radiolabeled DOTA-PSMA-617 tracers (17-20%IA/106 cells) in the same assay. CONCLUSIONS The AAZTA5-PSMA-617 structure proved fast and quantitative radiolabeling with all three radiometal complexes at room temperature, excellent stability with 44Sc, very high stability with 177Lu and medium stability with 68Ga in human serum, PBS and EDTA/DTPA solutions. All three AAZTA5-PSMA-617 tracers showed binding affinities and internalization ratios in LNCaP cells comparable with that of radiolabeled DOTA-PSMA-617 analogues. Therefore, the exchange of the chelator DOTA with AAZTA5 within the PSMA-617 binding motif has no negative influence on in vitro LNCaP cell binding characteristics. In combination with the faster and milder radiolabeling features, AAZTA5-PSMA-617 thus demonstrates promising potential for in vivo application for theranostics of prostate cancer.
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Affiliation(s)
- Jean-Philippe Sinnes
- Johannes Gutenberg-University Mainz, Department of Chemistry/ TRIGA, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany
| | - Ulrike Bauder-Wüst
- German Cancer Research Center (DKFZ), Division of Radiopharmaceutical Chemistry, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Martin Schäfer
- German Cancer Research Center (DKFZ), Division of Radiopharmaceutical Chemistry, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Euy Sung Moon
- Johannes Gutenberg-University Mainz, Department of Chemistry/ TRIGA, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany
| | - Klaus Kopka
- German Cancer Research Center (DKFZ), Division of Radiopharmaceutical Chemistry, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.,German Cancer Research Center (DKFZ), Division of Radiopharmaceutical Chemistry and German Cancer Consortium (DKTK), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.,New address: Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Frank Rösch
- Johannes Gutenberg-University Mainz, Department of Chemistry/ TRIGA, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany.
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Joaqui-Joaqui MA, Pandey MK, Bansal A, Raju MVR, Armstrong-Pavlik F, Dundar A, Wong HL, DeGrado TR, Pierre VC. Catechol-Based Functionalizable Ligands for Gallium-68 Positron Emission Tomography Imaging. Inorg Chem 2020; 59:12025-12038. [DOI: 10.1021/acs.inorgchem.0c00975] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- M. Andrey Joaqui-Joaqui
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mukesh K. Pandey
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, United States
| | - Aditya Bansal
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, United States
| | | | - Fiona Armstrong-Pavlik
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ayca Dundar
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, United States
| | - Henry L. Wong
- Department of Medicinal Chemistry and Institute for Therapeutics Discovery & Development, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Timothy R. DeGrado
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, United States
| | - Valérie C. Pierre
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Moon ES, Elvas F, Vliegen G, De Lombaerde S, Vangestel C, De Bruycker S, Bracke A, Eppard E, Greifenstein L, Klasen B, Kramer V, Staelens S, De Meester I, Van der Veken P, Rösch F. Targeting fibroblast activation protein (FAP): next generation PET radiotracers using squaramide coupled bifunctional DOTA and DATA 5m chelators. EJNMMI Radiopharm Chem 2020; 5:19. [PMID: 32728930 PMCID: PMC7391456 DOI: 10.1186/s41181-020-00102-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/15/2020] [Indexed: 12/19/2022] Open
Abstract
Background Fibroblast activation protein (FAP) is a proline selective serine protease that is overexpressed in tumor stroma and in lesions of many other diseases that are characterized by tissue remodeling. In 2014, a most potent FAP-inhibitor (referred to as UAMC1110) with low nanomolar FAP-affinity and high selectivity toward related enzymes such as prolyl oligopeptidase (PREP) and the dipeptidyl-peptidases (DPPs): DPP4, DPP8/9 and DPP2 were developed. This inhibitor has been adopted recently by other groups to create radiopharmaceuticals by coupling bifunctional chelator-linker systems. Here, we report squaric acid (SA) containing bifunctional DATA5m and DOTA chelators based on UAMC1110 as pharmacophor. The novel radiopharmaceuticals DOTA.SA.FAPi and DATA5m.SA.FAPi with their non-radioactive derivatives were characterized for in vitro inhibitory efficiency to FAP and PREP, respectively and radiochemical investigated with gallium-68. Further, first proof-of-concept in vivo animal study followed by ex vivo biodistribution were determined with [68Ga]Ga-DOTA.SA.FAPi. Results [68Ga]Ga-DOTA.SA.FAPi and [68Ga]Ga-DATA5m.SA.FAPi showed high complexation > 97% radiochemical yields after already 10 min and high stability over a period of 2 h. Affinity to FAP of DOTA.SA.FAPi and DATA5m.SA.FAPi and its natGa and natLu-labeled derivatives were excellent resulting in low nanomolar IC50 values of 0.7–1.4 nM. Additionally, all five compounds showed low affinity for the related protease PREP (high IC50 with 1.7–8.7 μM). First proof-of-principle in vivo PET-imaging animal studies of the [68Ga]Ga-DOTA.SA.FAPi precursor in a HT-29 human colorectal cancer xenograft mouse model indicated promising results with high accumulation in tumor (SUVmean of 0.75) and low background signal. Ex vivo biodistribution showed highest uptake in tumor (5.2%ID/g) at 60 min post injection with overall low uptake in healthy tissues. Conclusion In this work, novel PET radiotracers targeting fibroblast activation protein were synthesized and biochemically investigated. Critical substructures of the novel compounds are a squaramide linker unit derived from the basic motif of squaric acid, DOTA and DATA5m bifunctional chelators and a FAP-targeting moiety. In conclusion, these new FAP-ligands appear promising, both for further research and development as well as for first human application.
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Affiliation(s)
- Euy Sung Moon
- Department of Chemistry - TRIGA Site, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Filipe Elvas
- Department of Nuclear Medicine, Antwerp University Hospital (UZA), 2650, Edegem, Belgium
| | - Gwendolyn Vliegen
- Department of Pharmaceutical Sciences, Laboratory of Medical Biochemistry, University of Antwerp, 2610, Wilrijk, Belgium
| | - Stef De Lombaerde
- Department of Nuclear Medicine, Antwerp University Hospital (UZA), 2650, Edegem, Belgium
| | - Christel Vangestel
- Department of Nuclear Medicine, Antwerp University Hospital (UZA), 2650, Edegem, Belgium
| | - Sven De Bruycker
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, 2610, Wilrijk, Belgium
| | - An Bracke
- Department of Pharmaceutical Sciences, Laboratory of Medical Biochemistry, University of Antwerp, 2610, Wilrijk, Belgium
| | | | - Lukas Greifenstein
- Department of Chemistry - TRIGA Site, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Benedikt Klasen
- Department of Chemistry - TRIGA Site, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Vasko Kramer
- Positronpharma SA, 7500921 Providencia, Santiago, Chile
| | - Steven Staelens
- Molecular Imaging Center Antwerp (MICA), University of Antwerp, 2610, Wilrijk, Belgium
| | - Ingrid De Meester
- Department of Pharmaceutical Sciences, Laboratory of Medical Biochemistry, University of Antwerp, 2610, Wilrijk, Belgium
| | - Pieter Van der Veken
- Department of Pharmaceutical Sciences, Laboratory of Medical Biochemistry, University of Antwerp, 2610, Wilrijk, Belgium
| | - Frank Rösch
- Department of Chemistry - TRIGA Site, Johannes Gutenberg University Mainz, 55128, Mainz, Germany.
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Price TW, Yap SY, Gillet R, Savoie H, Charbonnière LJ, Boyle RW, Nonat AM, Stasiuk GJ. Evaluation of a Bispidine‐Based Chelator for Gallium‐68 and of the Porphyrin Conjugate as PET/PDT Theranostic Agent. Chemistry 2020; 26:7602-7608. [DOI: 10.1002/chem.201905776] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/27/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Thomas W. Price
- School of Life SciencesFaculty of Health SciencesUniversity of Hull Cottingham Road Hull HU6 7RX UK
- Positron Emission Tomography Research CenterUniversity of Hull Cottingham Road Hull HU6 7RX UK
- Department of Imaging Chemistry and BiologySchool of Biomedical Engineering and Imaging SciencesKing's College London Cottingham Road London SE1 7EH UK
| | - Steven Y. Yap
- Chemistry, School of Mathematical and Physical SciencesUniversity of Hull Cottingham Road Hull HU6 7RX UK
| | - Raphaël Gillet
- Equipe de Synthèse pour l'Analyse (SynPA)CNRS, IPHC UMR 7178Université de Strasbourg 67000 Strasbourg France
| | - Huguette Savoie
- Chemistry, School of Mathematical and Physical SciencesUniversity of Hull Cottingham Road Hull HU6 7RX UK
| | - Loïc J. Charbonnière
- Equipe de Synthèse pour l'Analyse (SynPA)CNRS, IPHC UMR 7178Université de Strasbourg 67000 Strasbourg France
| | - Ross W. Boyle
- Chemistry, School of Mathematical and Physical SciencesUniversity of Hull Cottingham Road Hull HU6 7RX UK
| | - Aline M. Nonat
- Equipe de Synthèse pour l'Analyse (SynPA)CNRS, IPHC UMR 7178Université de Strasbourg 67000 Strasbourg France
| | - Graeme J. Stasiuk
- School of Life SciencesFaculty of Health SciencesUniversity of Hull Cottingham Road Hull HU6 7RX UK
- Positron Emission Tomography Research CenterUniversity of Hull Cottingham Road Hull HU6 7RX UK
- Department of Imaging Chemistry and BiologySchool of Biomedical Engineering and Imaging SciencesKing's College London Cottingham Road London SE1 7EH UK
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Choudhary N, Guadalupe Jaraquemada-Peláez MD, Zarschler K, Wang X, Radchenko V, Kubeil M, Stephan H, Orvig C. Chelation in One Fell Swoop: Optimizing Ligands for Smaller Radiometal Ions. Inorg Chem 2020; 59:5728-5741. [DOI: 10.1021/acs.inorgchem.0c00509] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Neha Choudhary
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - Marı́a de Guadalupe Jaraquemada-Peláez
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Kristof Zarschler
- Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - Xiaozhu Wang
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Valery Radchenko
- Life Sciences Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Manja Kubeil
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, Germany
| | - Holger Stephan
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, Germany
| | - Chris Orvig
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
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Baranyai Z, Tircsó G, Rösch F. The Use of the Macrocyclic Chelator DOTA in Radiochemical Separations. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900706] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Zsolt Baranyai
- Bracco Research Centre Bracco Imaging spa Via Ribes 5 10010 Colleretto Giacosa (TO) Italy
| | - Gyula Tircsó
- Department of Physical Chemistry Faculty of Science and Technology University of Debrecen Egyetem tér 1 Debrecen 4032 Hungary
| | - Frank Rösch
- Institute of Nuclear Chemistry Johannes Gutenberg‐University of Mainz Fritz‐Strassmann‐Weg 2 55128 Mainz Germany
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Evaluation of [ 68Ga]Ga-DATA-TOC for imaging of neuroendocrine tumours: comparison with [ 68Ga]Ga-DOTA-NOC PET/CT. Eur J Nucl Med Mol Imaging 2019; 47:860-869. [PMID: 31754796 DOI: 10.1007/s00259-019-04611-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/11/2019] [Indexed: 12/21/2022]
Abstract
PURPOSE Recently, the new hybrid chelator DATA (6-amino-1,4-diazepine-triacetate) has been introduced, which has the advantage of high yield and radiolabelling of DATA-based octreotide derivative (TOC) at room temperature in contrast to tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA) that needs 95 °C for effective labelling. However, the diagnostic potential of DATA-TOC has not been studied with other chelators in humans. The aim of this study was to compare the diagnostic efficacy of [68Ga]Ga-DATA-TOC with [68Ga]Ga-DOTA-NOC (which is the current standard for imaging neuroendocrine tumours (NET)) in patients of gastroenteropancreatic neuroendocrine tumours (GEP-NETs). METHODS Fifty patients (thirty-one males and nineteen females) with biopsy-proven GEP-NETs were included in the study. Patients age ranged from 14 to 75 years (mean 46.11 years). All patients underwent two PET studies with [68Ga]Ga-DATA-TOC and [68Ga]Ga-DOTA-NOC. Images were evaluated visually and semi-quantitatively using maximum standardized uptake values (SUVmax) of tumour, mediastinum and liver. Tumour-to-liver (T/L) and tumour-to-mediastinum (T/M) SUVmax ratios were computed. For the purpose of comparison, patient-wise as well as lesion-wise analysis was carried out. The nonparametric-related samples Wilcoxon signed-rank test was used for comparison of the SUVmax values and ratios. RESULTS On visual evaluation, the biodistribution and image quality of [68Ga]Ga-DATA-TOC was similar to [68Ga]Ga-DOTA-NOC. Physiological liver uptake was lower in [68Ga]Ga-DATA-TOC as compared with [68Ga]Ga-DOTA-NOC, 7.65 ± 5.37 vs 8.94 ± 5.95 (p = 0.009), respectively. On a patient-wise analysis, both [68Ga]Ga-DATA-TOC and [68Ga]Ga-DOTA-NOC were lesion-positive in the 44 patients (88%) and were negative in the 6 patients (12%). On a lesion-based analysis, [68Ga]Ga-DATA-TOC had 98.6% concordance with [68Ga]Ga-DOTA-NOC (232 out of 235 lesions detected). The target tumour SUVmax on [68Ga]Ga-DATA-TOC and [68Ga]Ga-DOTA-NOC were 36.63 ± 32.24 and 40.82 ± 36.89, respectively (p = 0.097). The T/L SUVmax ratios were not significantly different (5.99 ± 5.52 vs 5.67 ± 4.96, p = 0.77). CONCLUSION [68Ga]Ga-DATA-TOC PET/CT imaging produced results that were comparable with [68Ga]Ga-DOTA-NOC. It, thus, has potential utility as an effective and safe alternative to 68Ga-DOTA-NOC with the added benefit of ease, cost-effective and improved yield of instant kit-type synthesis.
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22
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Piras AM, Fabiano A, Sartini S, Zambito Y, Braccini S, Chiellini F, Cataldi AG, Bartoli F, de la Fuente A, Erba PA. pH-Responsive Carboxymethylcellulose Nanoparticles for 68Ga-WBC Labeling in PET Imaging. Polymers (Basel) 2019; 11:polym11101615. [PMID: 31590371 PMCID: PMC6835547 DOI: 10.3390/polym11101615] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023] Open
Abstract
Carboxymethylcellulose (CMC) is a well-known pharmaceutical polymer, recently gaining attention in the field of nanomedicine, especially as a polyelectrolyte agent for the formation of complexes with oppositely charged macromolecules. Here, we report on the application of pH-sensitive pharmaceutical grade CMC-based nanoparticles (NP) for white blood cells (WBC) PET imaging. In this context and as an alternative to 99mTc-HMPAO SPECT labeling, the use of 68Ga3+ as PET radionuclide was investigated since, at early time points, it could provide the greater spatial resolution and patient convenience of PET tomography over SPECT clinical practices. Two operator-friendly kit-type formulations were compared, with the intention of radiolabeling within a short time (10 min), under mild conditions (physiological pH, room temperature) and in agreement with the actual clinically applied guidelines. NP were labeled by directly using 68Ga3+ eluted in HCL 0.05 N, from hospital suited 68Ge/68Ga generator and in absence of chelator. The first kit type approach involved the application of 68Ga3+ as an ionotropic gelation agent for in-situ forming NP. The second kit type approach concerned the re-hydration of a proper freeze-dried injectable NP powder. pH-sensitive NP with 250 nm average diameter and 80% labeling efficacy were obtained. The NP dispersant medium, including a cryoprotective agent, was modulated in order to optimize the Zeta potential value (−18 mV), minimize the NP interaction with serum proteins and guarantee a physiological environment for WBC during NP incubation. Time-dependent WBC radiolabeling was correlated to NP uptake by using both confocal and FT-IR microscopies. The ready to use lyophilized NP formulation approach appears promising as a straightforward 68Ga-WBC labeling tool for PET imaging applications.
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Affiliation(s)
- Anna Maria Piras
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126, Pisa, Italy.
| | - Angela Fabiano
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126, Pisa, Italy.
| | - Stefania Sartini
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126, Pisa, Italy.
| | - Ylenia Zambito
- Department of Pharmacy, University of Pisa, Via Bonanno 33, 56126, Pisa, Italy.
| | - Simona Braccini
- Department of Chemistry and Industrial Chemistry, UdR INSTM - Pisa, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.
| | - Federica Chiellini
- Department of Chemistry and Industrial Chemistry, UdR INSTM - Pisa, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.
| | - Angela G Cataldi
- Nuclear Medicine, Department of Translational Research and Advanced Technologies in Medicine and Surgery, University of Pisa and Azienda Ospedaliero Universitaria Pisana, 56126 Pisa, Italy.
| | - Francesco Bartoli
- Nuclear Medicine, Department of Translational Research and Advanced Technologies in Medicine and Surgery, University of Pisa and Azienda Ospedaliero Universitaria Pisana, 56126 Pisa, Italy.
| | - Ana de la Fuente
- Nuclear Medicine, Department of Translational Research and Advanced Technologies in Medicine and Surgery, University of Pisa and Azienda Ospedaliero Universitaria Pisana, 56126 Pisa, Italy.
| | - Paola Anna Erba
- Nuclear Medicine, Department of Translational Research and Advanced Technologies in Medicine and Surgery, University of Pisa and Azienda Ospedaliero Universitaria Pisana, 56126 Pisa, Italy.
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Metal-Based Complexes as Pharmaceuticals for Molecular Imaging of the Liver. Pharmaceuticals (Basel) 2019; 12:ph12030137. [PMID: 31527492 PMCID: PMC6789861 DOI: 10.3390/ph12030137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/13/2022] Open
Abstract
This article reviews the use of metal complexes as contrast agents (CA) and radiopharmaceuticals for the anatomical and functional imaging of the liver. The main focus was on two established imaging modalities: magnetic resonance imaging (MRI) and nuclear medicine, the latter including scintigraphy and positron emission tomography (PET). The review provides an overview on approved pharmaceuticals like Gd-based CA and 99mTc-based radiometal complexes, and also on novel agents such as 68Ga-based PET tracers. Metal complexes are presented by their imaging modality, with subsections focusing on their structure and mode of action. Uptake mechanisms, metabolism, and specificity are presented, in context with advantages and limitations of the diagnostic application and taking into account the respective imaging technique.
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24
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Gaertner F, Plum T, Kreppel B, Eppard E, Meisenheimer M, Strunk H, Bundschuh R, Sinnes J, Rösch F, Essler M. Clinical evaluation of [68Ga]Ga-DATA-TOC in comparison to [68Ga]Ga-DOTA-TOC in patients with neuroendocrine tumours. Nucl Med Biol 2019; 76-77:1-9. [DOI: 10.1016/j.nucmedbio.2019.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 08/07/2019] [Accepted: 08/26/2019] [Indexed: 01/20/2023]
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25
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Greifenstein L, Grus T, Nagel J, Sinnes JP, Rösch F. Synthesis and labeling of a squaric acid containing PSMA-inhibitor coupled to AAZTA 5 for versatile labeling with 44Sc, 64Cu, 68Ga and 177Lu. Appl Radiat Isot 2019; 156:108867. [PMID: 31883763 DOI: 10.1016/j.apradiso.2019.108867] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/25/2019] [Accepted: 08/14/2019] [Indexed: 01/02/2023]
Affiliation(s)
- Lukas Greifenstein
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Mainz, Germany, Fritz-Strassmann-Weg 2, 55128, Mainz
| | - Tilmann Grus
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Mainz, Germany, Fritz-Strassmann-Weg 2, 55128, Mainz
| | - Johannes Nagel
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Mainz, Germany, Fritz-Strassmann-Weg 2, 55128, Mainz
| | - Jean Phillip Sinnes
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Mainz, Germany, Fritz-Strassmann-Weg 2, 55128, Mainz
| | - Frank Rösch
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Mainz, Germany, Fritz-Strassmann-Weg 2, 55128, Mainz.
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26
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Farkas E, Vágner A, Negri R, Lattuada L, Tóth I, Colombo V, Esteban-Gómez D, Platas-Iglesias C, Notni J, Baranyai Z, Giovenzana GB. PIDAZTA: Structurally Constrained Chelators for the Efficient Formation of Stable Gallium-68 Complexes at Physiological pH. Chemistry 2019; 25:10698-10709. [PMID: 31149749 DOI: 10.1002/chem.201901512] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/28/2019] [Indexed: 12/11/2022]
Abstract
Two structurally constrained chelators based on a fused bicyclic scaffold, 4-amino-4-methylperhydro-pyrido[1,2-a][1,4]diazepin-N,N',N'-triacetic acids [(4R*,10aS*)-PIDAZTA (L1) and (4R*,10aR*)-PIDAZTA (L2)], were designed for the preparation of GaIII -based radiopharmaceuticals. The stereochemistry of the ligand scaffold has a deep impact on the properties of the complexes, with unexpected [Ga(L2)OH] species being superior in terms of both thermodynamic stability and inertness. This peculiar behavior was rationalized on the basis of molecular modeling and appears to be related to a better fit in size of GaIII into the cavity of L2. Fast and efficient formation of the GaIII chelates at room temperature was observed at pH values between 7 and 8, which enables 68 Ga radiolabeling under truly physiological conditions (pH 7.4).
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Affiliation(s)
- Edit Farkas
- Dept. of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4010, Debrecen, Hungary
| | - Adrienn Vágner
- Dept. of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4010, Debrecen, Hungary
| | - Roberto Negri
- Dip. di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2/3, 28100, Novara, Italy
| | - Luciano Lattuada
- Bracco Imaging spa, Bracco Research Centre, Via Ribes 5, 10010, Colleretto Giacosa (TO), Italy
| | - Imre Tóth
- Dept. of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4010, Debrecen, Hungary.,Dept. of Physical Chemistry, University of Debrecen, Egyetem tér 1, H-4010, Debrecen, Hungary
| | - Valentina Colombo
- Dip. di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133, Milano, Italy
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Dep. de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Dep. de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Johannes Notni
- Institute of Pathology, Technische Universität München, Trogerstrasse 18, 81675, Munich, Germany
| | - Zsolt Baranyai
- Dept. of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4010, Debrecen, Hungary.,Bracco Imaging spa, Bracco Research Centre, Via Ribes 5, 10010, Colleretto Giacosa (TO), Italy
| | - Giovanni B Giovenzana
- Dip. di Scienze del Farmaco, Università del Piemonte Orientale, Largo Donegani 2/3, 28100, Novara, Italy
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27
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Sinnes JP, Nagel J, Rösch F. AAZTA 5/AAZTA 5-TOC: synthesis and radiochemical evaluation with 68Ga, 44Sc and 177Lu. EJNMMI Radiopharm Chem 2019; 4:18. [PMID: 31659525 PMCID: PMC6675801 DOI: 10.1186/s41181-019-0068-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 07/16/2019] [Indexed: 11/10/2022] Open
Abstract
PURPOSE AAZTA (1,4-bis (carboxymethyl)-6-[bis (carboxymethyl)]amino-6-methylperhydro-1,4-diazepine) based chelators were initially developed in the context of magnetic resonance imaging. First radiochemical studies showed the capability of AAZTA to form stable complexes with radiolanthanides and moderately stable complexes with 68Ga. For a systematic comparison of the labelling capabilities with current diagnostic and therapeutic trivalent radiometals, AAZTA5 (1,4-bis (carboxymethyl)-6-[bis (carboxymethyl)]amino-6-[pentanoic-acid]perhydro-1,4-diazepine) was synthesized representing a bifunctional version with a pentanoic acid at the carbon-6 atom. To evaluate the effect of adding a targeting vector (TV) to the bifunctional chelator on the complex formation, AAZTA5-TOC was synthesized, radiolabeled and tested in comparison to the uncoupled AAZTA5. METHODS AAZTA5 was synthesized in a 5-step synthesis. It was coupled to the cyclic peptide TOC (Phe1-Tyr3 octreotide) via amide bound formation. AAZTA and AAZTA5-TOC complex formations with 68Ga, 44Sc and 177Lu were investigated at different pH, temperature and precursor amounts. Stability studies against human serum, PBS buffer, EDTA and DTPA were performed. RESULTS AAZTA5 and AAZTA5-TOC achieved quantitative labelling (> 95%) at room temperature in less than 5 min with all three nuclides at pH ranges from 4 to 5.5 with low precursor amounts of 1 to 10 nmol. [44Sc]Sc-AAZTA5 complexes as well as [44Sc]Sc-AAZTA5-TOC were completely stable. The 177Lu complexes of AAZTA5 and AAZTA5-TOC showed high stability comparable to the 44Sc complexes. In contrast, the [68Ga]Ga-AAZTA5 complex stability was rather low, but interestingly, [68Ga]Ga-AAZTA5-TOC was completely stable. CONCLUSION AAZTA5 appears to be a promising bifunctional chelator for 68Ga, 44Sc and 177Lu with outstanding labelling capabilities at room temperature. Complex stabilities are high in the case of 44Sc and 177Lu. While [68Ga]Ga-AAZTA complexes alone lacking stability, [68Ga]Ga-AAZTA5-TOC demonstrated high stability. The latter indicates an interesting feature of [68Ga]Ga-AAZTA5-labelled radiopharmaceuticals.
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Affiliation(s)
- Jean-Philippe Sinnes
- Johannes Gutenberg-University Mainz, Institute of Nuclear Chemistry, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany
| | - Johannes Nagel
- Johannes Gutenberg-University Mainz, Institute of Nuclear Chemistry, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany
| | - Frank Rösch
- Johannes Gutenberg-University Mainz, Institute of Nuclear Chemistry, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany.
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28
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Sinnes JP, Nagel J, Waldron BP, Maina T, Nock BA, Bergmann RK, Ullrich M, Pietzsch J, Bachmann M, Baum RP, Rösch F. Instant kit preparation of 68Ga-radiopharmaceuticals via the hybrid chelator DATA: clinical translation of [ 68Ga]Ga-DATA-TOC. EJNMMI Res 2019; 9:48. [PMID: 31123943 PMCID: PMC6533321 DOI: 10.1186/s13550-019-0516-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 05/06/2019] [Indexed: 01/29/2023] Open
Abstract
Purpose The widespread use of 68Ga for positron emission tomography (PET) relies on the development of radiopharmaceutical precursors that can be radiolabelled and dispensed in a simple, quick, and convenient manner. The DATA (6-amino-1,4-diazapine-triacetate) scaffold represents a novel hybrid chelator architecture possessing both cyclic and acyclic character that may allow for facile access to 68Ga-labelled tracers in the clinic. We report the first bifunctional DATA chelator conjugated to [Tyr3]octreotide (TOC), a somatostatin subtype 2 receptor (SST2)-targeting vector for imaging and functional characterisation of SSTR2 expressing tumours. Methods The radiopharmaceutical precursor, DATA-TOC, was synthesised as previously described and used to complex natGa(III) and 68Ga(III). Competition binding assays of [natGa]Ga-DATA-TOC or [natGa]Ga-DOTA-TOC against [125I-Tyr25]LTT-SS28 were conducted in membranes of HEK293 cells transfected to stably express one of the hSST2,3,5 receptor subtypes (HEK293-hSST2/3/5 cells). First in vivo studies were performed in female NMRI-nude mice bearing SST2-positive mouse phaeochromocytoma mCherry (MPC-mCherry) tumours to compare the in vivo SST2-specific tumour-targeting of [68Ga]Ga-DATA-TOC and its overall pharmacokinetics versus the [68Ga]Ga-DOTA-TOC reference. A direct comparison of [68Ga]Ga-DATA-TOC with the well-established PET radiotracer [68Ga]Ga-DOTA-TOC was additionally performed in a 46-year-old male patient with a well-differentiated NET (neuroendocrine tumour), representing the first in human administration of [68Ga]Ga-DATA-TOC. Results DATA-TOC was labelled with 68Ga with a radiolabelling efficiency of > 95% in less than 10 min at ambient temperature. A molar activity up to 35 MBq/nmol was achieved. The hSST2-affinities of [natGa]Ga-DATA-TOC and [natGa]Ga-DOTA-TOC were found similar with only sub-nanomolar differences in the respective IC50 values. In mice, [68Ga]Ga-DATA-TOC was able to visualise the tumour lesions, showing standardised uptake values (SUVs) similar to [68Ga]Ga-DOTA-TOC. Direct comparison of the two PET tracers in a NET patient revealed very similar tumour uptake for the two 68Ga-radiotracers, but with a higher tumour-to-liver contrast for [68Ga]Ga-DATA-TOC. Conclusion [68Ga]Ga-DATA-TOC was prepared, to a quality appropriate for in vivo use, following a highly efficient kit type process. Furthermore, the novel radiopharmaceutical was comparable or better than [68Ga]Ga-DOTA-TOC in all preclinical tests, achieving a higher tumour-to-liver contrast in a NET-patient. The results illustrate the potential of the DATA-chelator to facilitate the access to and preparation of 68Ga-radiotracers in a routine clinical radiopharmacy setting. Electronic supplementary material The online version of this article (10.1186/s13550-019-0516-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jean-Philippe Sinnes
- Institute of Nuclear Chemistry, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Johannes Nagel
- Institute of Nuclear Chemistry, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Bradley P Waldron
- Institute of Nuclear Chemistry, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES NCSR 'Demokritos', Athens, Greece
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES NCSR 'Demokritos', Athens, Greece
| | - Ralf K Bergmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany
| | - Martin Ullrich
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany.,School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Michael Bachmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany.,Technische Universität Dresden, Universitätsklinikum 'Carl Gustav Carus', UniversitätsKrebsCentrum (UCC), Tumorimmunology, Dresden, Germany.,National Center for Tumor Diseases (NCT), Technische Universität Dresden, Dresden, Germany
| | - Richard P Baum
- Zentralklinik Bad Berka GmbH, Clinic for Molecular Radiotherapy, Bad Berka, Germany
| | - Frank Rösch
- Institute of Nuclear Chemistry, Johannes Gutenberg-University Mainz, Mainz, Germany.
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29
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Imberti C, Chen YL, Foley CA, Ma MT, Paterson BM, Wang Y, Young JD, Hider RC, Blower PJ. Tuning the properties of tris(hydroxypyridinone) ligands: efficient 68Ga chelators for PET imaging. Dalton Trans 2019; 48:4299-4313. [PMID: 30860215 PMCID: PMC6469224 DOI: 10.1039/c8dt04454f] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/11/2019] [Indexed: 12/31/2022]
Abstract
The prototype tris(1,6-dimethyl-3-hydroxypyridin-4-one) chelator for gallium-68, THPMe, has shown great promise for rapid and efficient kit-based 68Ga labelling of PET radiopharmaceuticals. Peptide derivatives of THPMe have been used to image expression of their target receptors in vivo in preclinical and clinical studies. Herein we describe new synthetic routes to the THP platform including replacing the 1,6-dimethyl-3-hydroxypyridin-4-one N1-CH3 group of THPMe with O (tris(6-methyl-3-hydroxypyran-4-one, THPO) and N1-H (tris(6-methyl-3-hydroxypyridin-4-one), THPH) groups. The effect of these structural modifications on lipophilicity, gallium binding and metal ion selectivity was investigated. THPH was able to bind 68Ga in extremely mild conditions (5 min, room temperature, pH 6, 1 μM ligand concentration) and, notably, in vivo, when administered to a mouse previously injected with 68Ga acetate. The 67Ga radiolabelled complex was stable in serum for more than 7 days. [68Ga(THPH)] displayed a log P value of -2.40 ± 0.02, less negative than the log P = -3.33 ± 0.02 measured for [68Ga(THPMe)], potentially due to an increase in intramolecular hydrogen bonding attributable to the N1-H pyridinone units. Spectrophotometric determination of the Ga3+/Fe3+ complex formation constants for both THPMe and THPH revealed their preference for binding Ga3+ over Fe3+, which enabled selective labelling with 68Ga3+ in the presence of a large excess of Fe3+ in both cases. Compared to THPMe, THPH showed significantly reduced affinity for Fe3+, increased affinity for Ga3+ and improved radiolabelling efficiency. THPO was inferior to both THPH and THPMe in terms of labelling efficiency, but its benzylated precursor Bn-THPO (tris(6-methyl-3-benzyloxypyran-4-one)) provides a potential platform for the synthesis of a library of THP compounds with tunable chemical properties and metal preferences.
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Affiliation(s)
- Cinzia Imberti
- King's College London
, School of Biomedical Engineering and Imaging Sciences
, St Thomas’ Hospital
,
London SE1 7EH
, UK
.
;
| | - Yu-Lin Chen
- King's College London
, School of Biomedical Sciences
, Institute of Pharmaceutical Science
,
London
, SE1 9NH UK
| | - Calum A. Foley
- King's College London
, School of Biomedical Engineering and Imaging Sciences
, St Thomas’ Hospital
,
London SE1 7EH
, UK
.
;
| | - Michelle T. Ma
- King's College London
, School of Biomedical Engineering and Imaging Sciences
, St Thomas’ Hospital
,
London SE1 7EH
, UK
.
;
| | - Brett M. Paterson
- King's College London
, School of Biomedical Engineering and Imaging Sciences
, St Thomas’ Hospital
,
London SE1 7EH
, UK
.
;
- University of Melbourne
, School of Chemistry
,
Melbourne
, VIC 3010
, Australia
| | - Yifu Wang
- King's College London
, School of Biomedical Engineering and Imaging Sciences
, St Thomas’ Hospital
,
London SE1 7EH
, UK
.
;
| | - Jennifer D. Young
- King's College London
, School of Biomedical Engineering and Imaging Sciences
, St Thomas’ Hospital
,
London SE1 7EH
, UK
.
;
| | - Robert C. Hider
- King's College London
, School of Biomedical Sciences
, Institute of Pharmaceutical Science
,
London
, SE1 9NH UK
| | - Philip J. Blower
- King's College London
, School of Biomedical Engineering and Imaging Sciences
, St Thomas’ Hospital
,
London SE1 7EH
, UK
.
;
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30
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Abstract
Radiometals possess an exceptional breadth of decay properties and have been applied to medicine with great success for several decades. The majority of current clinical use involves diagnostic procedures, which use either positron-emission tomography (PET) or single-photon imaging to detect anatomic abnormalities that are difficult to visualize using conventional imaging techniques (e.g., MRI and X-ray). The potential of therapeutic radiometals has more recently been realized and relies on ionizing radiation to induce irreversible DNA damage, resulting in cell death. In both cases, radiopharmaceutical development has been largely geared toward the field of oncology; thus, selective tumor targeting is often essential for efficacious drug use. To this end, the rational design of four-component radiopharmaceuticals has become popularized. This Review introduces fundamental concepts of drug design and applications, with particular emphasis on bifunctional chelators (BFCs), which ensure secure consolidation of the radiometal and targeting vector and are integral for optimal drug performance. Also presented are detailed accounts of production, chelation chemistry, and biological use of selected main group and rare earth radiometals.
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Affiliation(s)
- Thomas I Kostelnik
- Medicinal Inorganic Chemistry Group, Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Chris Orvig
- Medicinal Inorganic Chemistry Group, Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
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31
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Gai Y, Sun L, Lan X, Zeng D, Xiang G, Ma X. Synthesis and Evaluation of New Bifunctional Chelators with Phosphonic Acid Arms for Gallium-68 Based PET Imaging in Melanoma. Bioconjug Chem 2018; 29:3483-3494. [PMID: 30205001 DOI: 10.1021/acs.bioconjchem.8b00642] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Due to the increasing use of generator-produced radiometal Gallium-68 (68Ga) in positron-emission tomography/computed tomography (PET/CT), reliable bifunctional chelators that can efficiently incorporate 68Ga3+ into biomolecules are highly desirable. In this study, we synthesized two new bifunctional chelators bearing one or two phosphonic acid functional groups, named p-SCN-PhPr-NE2A1P and p-SCN-PhPr-NE2P1A, with the aim of enabling facile production of 68Ga-based radiopharmaceuticals. Both chelators were successfully conjugated to LLP2A-PEG4, a very late antigen-4 (VLA-4) targeting peptidomimetic ligand, to evaluate their application in 68Ga-based PET imaging. NE2P1A-PEG4-LLP2A exhibited the highest 68Ga3+ binding ability with molar activity of 37 MBq/nmol under mild temperature and neutral pH. Excellent serum stability of 68Ga-NE2P1A-PEG4-LLP2A was observed, which was consistent with the result obtained from density functional theory calculation. The in vitro cell study showed that 68Ga-NE2P1A-PEG4-LLP2A had significantly longer retention in B16F10 cells comparing to the reported retention of 64Cu-NE3TA-PEG4-LLP2A, although the uptake was relatively lower. In the biodistribution and micro-PET/CT imaging studies, high tumor uptake and low background were observed after 68Ga-NE2P1A-PEG4-LLP2A was injected into mice bearing B16F10 tumor xenografts, making it a highly promising radiotracer for noninvasive imaging of VLA-4 receptors overexpressed in melanoma.
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Affiliation(s)
- Yongkang Gai
- School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , 13 Hangkong Road , Wuhan 430030 , China
| | - Lingyi Sun
- Center for Radiochemistry Research, Department of Diagnostic Radiology , Oregon Health & Science University , Portland , Oregon 97239 , United States
| | | | - Dexing Zeng
- Center for Radiochemistry Research, Department of Diagnostic Radiology , Oregon Health & Science University , Portland , Oregon 97239 , United States
| | - Guangya Xiang
- School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , 13 Hangkong Road , Wuhan 430030 , China
| | - Xiang Ma
- School of Pharmacy, Tongji Medical College , Huazhong University of Science and Technology , 13 Hangkong Road , Wuhan 430030 , China
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Yap SY, Price TW, Savoie H, Boyle RW, Stasiuk GJ. Selective radiolabelling with 68Ga under mild conditions: a route towards a porphyrin PET/PDT theranostic agent. Chem Commun (Camb) 2018; 54:7952-7954. [PMID: 29956694 DOI: 10.1039/c8cc03897j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A theranostic conjugate for use as a positron emission tomography (PET) radiotracer and as a photosensitiser for photodynamic therapy (PDT) has been synthesised. A water-soluble porphyrin was coupled with the bifunctional chelate, H4Dpaa.ga. This conjugate is capable of rapid 68Ga complexation under physiological conditions; with 93% and 80% radiochemical yields achieved, at pH 4.5 and pH 7.4 respectively, in 15 min at 25 °C. Photocytotoxicity was evaluated on HT-29 cells and showed the conjugate was capable of >50% cell death at 50 μM upon irradiation with light, while causing minimal toxicity in the absence of light (>95% cell survival).
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Affiliation(s)
- Steven Y Yap
- Chemistry, School of Mathematics and Physical Sciences, Faculty of Science and Engineering, University of Hull, HU6 7RX, UK.
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33
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Greiser J, Kühnel C, Görls H, Weigand W, Freesmeyer M. N,1,4-Tri(4-alkoxy-2-hydroxybenzyl)-DAZA: efficient one-pot synthesis and labelling with 68Ga for PET liver imaging in ovo. Dalton Trans 2018; 47:9000-9007. [PMID: 29923561 DOI: 10.1039/c8dt01038b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We report the isolation of a new type of 1,4-diazepan-6-amine (DAZA)-based ligand. Condensation of aldehydes with DAZA gives a novel class of 1,5-diazabicyclo[3.2.1]octanes in nearly quantitative yields. Subsequent reductive cleavage of these bicyclic aminal species with sodium borohydride selectively leads to N,1,4-tri(4-alkoxy-2-hydroxybenzyl)-1,4-diazepan-6-amines (alkoxy = Me: TMeOHB-DAZA; alkoxy = Et: TEtOHB-DAZA) via a unique reductive alkylation reaction in which a substituent is added to the DAZA moiety without the presence of an alkylating agent. Mass spectrometry studies of the intermediates suggest that the mechanism involves insertion of in situ released carbonyl species into an aminal bond to form hemiaminal intermediates, and subsequent reduction. TMeOHB-DAZA and TEtOHB-DAZA are hexadentate ligands suitable for effectively coordinating Ga(iii) ions. Chelation of the radionuclide 68Ga was achieved within 5 min at 100 °C. In vitro stability studies in PBS and human serum confirmed the kinetic inertness of the tracers as no 68Ga demetallation was observed over a period of 4 h. Positron emission tomography (PET)/computed tomography (CT) imaging after in ovo administration to incubated ostrich eggs showed a high uptake in the liver, namely 27% (60 min post injection), and subsequent biliary excretion. These results suggest that [68Ga]Ga-TMeOHB-DAZA and [68Ga]Ga-TEtOHB-DAZA have excellent potential as hepatobiliary PET/CT imaging agents.
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Affiliation(s)
- Julia Greiser
- University Hospital Jena, Clinic of Nuclear Medicine, Am Klinikum 1, 07747 Jena, Germany.
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Price TW, Greenman J, Stasiuk GJ. Current advances in ligand design for inorganic positron emission tomography tracers 68Ga, 64Cu, 89Zr and 44Sc. Dalton Trans 2018; 45:15702-15724. [PMID: 26865360 DOI: 10.1039/c5dt04706d] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A key part of the development of metal based Positron Emission Tomography probes is the chelation of the radiometal. In this review the recent developments in the chelation of four positron emitting radiometals, 68Ga, 64Cu, 89Zr and 44Sc, are explored. The factors that effect the chelation of each radio metal and the ideal ligand system will be discussed with regards to high in vivo stability, complexation conditions, conjugation to targeting motifs and complexation kinetics. A series of cyclic, cross-bridged and acyclic ligands will be discussed, such as CP256 which forms stable complexes with 68Ga under mild conditions and PCB-TE2A which has been shown to form a highly stable complex with 64Cu. 89Zr and 44Sc have seen significant development in recent years with a number of chelates being applied to each metal - eight coordinate di-macrocyclic terephthalamide ligands were found to rapidly produce more stable complexes with 89Zr than the widely used DFO.
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Affiliation(s)
- Thomas W Price
- School of Biological, Biomedical and Environmental Sciences, The University of Hull, HU6 7RX, UK. and Positron Emission Tomography Research Centre, The University of Hull, HU6 7RX, UK
| | - John Greenman
- School of Biological, Biomedical and Environmental Sciences, The University of Hull, HU6 7RX, UK.
| | - Graeme J Stasiuk
- School of Biological, Biomedical and Environmental Sciences, The University of Hull, HU6 7RX, UK. and Positron Emission Tomography Research Centre, The University of Hull, HU6 7RX, UK
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Tsionou MI, Knapp CE, Foley CA, Munteanu CR, Cakebread A, Imberti C, Eykyn TR, Young JD, Paterson BM, Blower PJ, Ma MT. Comparison of macrocyclic and acyclic chelators for gallium-68 radiolabelling. RSC Adv 2017; 7:49586-49599. [PMID: 29308192 PMCID: PMC5708347 DOI: 10.1039/c7ra09076e] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/06/2017] [Indexed: 01/12/2023] Open
Abstract
Gallium-68 (68Ga) is a positron-emitting isotope used for clinical PET imaging of peptide receptor expression. 68Ga radiopharmaceuticals used in molecular PET imaging consist of disease-targeting biomolecules tethered to chelators that complex 68Ga3+. Ideally, the chelator will rapidly, quantitatively and stably coordinate 68Ga3+ at room temperature, near neutral pH and low chelator concentration, allowing for simple routine radiopharmaceutical formulation. Identification of chelators that fulfil these requirements will facilitate development of kit-based 68Ga radiopharmaceuticals. Herein the reaction of a range of widely used macrocyclic and acyclic chelators with 68Ga3+ is reported. Radiochemical yields have been measured under conditions of varying chelator concentrations, pH (3.5 and 6.5) and temperature (25 and 90 °C). These chelators are: 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA), 1,4,7-triazacyclononane macrocycles substituted with phosphonic (NOTP) and phosphinic (TRAP) groups at the amine, bis(2-hydroxybenzyl)ethylenediaminediacetic acid (HBED), a tris(hydroxypyridinone) containing three 1,6-dimethyl-3-hydroxypyridin-4-one groups (THP) and the hexadentate tris(hydroxamate) siderophore desferrioxamine-B (DFO). Competition studies have also been undertaken to assess relative complexation efficiencies of each chelator for 68Ga3+ under different pH and temperature conditions. Performing radiolabelling reactions at pH 6.5, 25 °C and 5-50 μM chelator concentration resulted in near quantitative radiochemical yields for all chelators, except DOTA. Radiochemical yields either decreased or were not substantially improved when the reactions were undertaken at lower pH or at higher temperature, except in the case of DOTA. THP and DFO were the most effective 68Ga3+ chelators at near-neutral pH and 25 °C, rapidly providing near-quantitative radiochemical yields at very low chelator concentrations. NOTP and HBED were only slightly less effective under these conditions. In competition studies with all other chelators, THP demonstrated highest reactivity for 68Ga3+ complexation under all conditions. These data point to THP possessing ideal properties for rapid, one-step kit-based syntheses of 68Ga-biomolecules for molecular PET imaging. LC-MS and 1H, 13C{1H} and 71Ga NMR studies of HBED complexes of Ga3+ showed that under the analytical conditions employed in this study, multiple HBED-bound Ga complexes exist. X-ray diffraction data indicated that crystals isolated from these solutions contained octahedral [Ga(HBED)(H2O)], with HBED coordinated in a pentadentate N2O3 mode, with only one phenolic group coordinated to Ga3+, and the remaining coordination site occupied by a water molecule.
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Affiliation(s)
- Maria Iris Tsionou
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
| | - Caroline E Knapp
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - Calum A Foley
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
| | - Catherine R Munteanu
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
| | - Andrew Cakebread
- Division of Analytical and Environmental Sciences, King's College London, Franklin Wilkin's Building, London SE1 9NH, UK
| | - Cinzia Imberti
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
| | - Thomas R Eykyn
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
| | - Jennifer D Young
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
| | - Brett M Paterson
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 3010, Victoria, Australia
| | - Philip J Blower
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
| | - Michelle T Ma
- King's College London, Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, London SE1 7EH, UK.
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36
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New Insights in the Design of Bioactive Peptides and Chelating Agents for Imaging and Therapy in Oncology. Molecules 2017; 22:molecules22081282. [PMID: 28767081 PMCID: PMC6152110 DOI: 10.3390/molecules22081282] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/25/2017] [Indexed: 11/16/2022] Open
Abstract
Many synthetic peptides have been developed for diagnosis and therapy of human cancers based on their ability to target specific receptors on cancer cell surface or to penetrate the cell membrane. Chemical modifications of amino acid chains have significantly improved the biological activity, the stability and efficacy of peptide analogues currently employed as anticancer drugs or as molecular imaging tracers. The stability of somatostatin, integrins and bombesin analogues in the human body have been significantly increased by cyclization and/or insertion of non-natural amino acids in the peptide sequences. Moreover, the overall pharmacokinetic properties of such analogues and others (including cholecystokinin, vasoactive intestinal peptide and neurotensin analogues) have been improved by PEGylation and glycosylation. Furthermore, conjugation of those peptide analogues to new linkers and bifunctional chelators (such as AAZTA, TETA, TRAP, NOPO etc.), produced radiolabeled moieties with increased half life and higher binding affinity to the cognate receptors. This review describes the most important and recent chemical modifications introduced in the amino acid sequences as well as linkers and new bifunctional chelators which have significantly improved the specificity and sensitivity of peptides used in oncologic diagnosis and therapy.
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Young JD, Abbate V, Imberti C, Meszaros LK, Ma MT, Terry SYA, Hider RC, Mullen GE, Blower PJ. 68Ga-THP-PSMA: A PET Imaging Agent for Prostate Cancer Offering Rapid, Room-Temperature, 1-Step Kit-Based Radiolabeling. J Nucl Med 2017; 58:1270-1277. [PMID: 28408532 PMCID: PMC6175039 DOI: 10.2967/jnumed.117.191882] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/03/2017] [Indexed: 01/06/2023] Open
Abstract
The clinical impact and accessibility of 68Ga tracers for the prostate-specific membrane antigen (PSMA) and other targets would be greatly enhanced by the availability of a simple, 1-step kit-based labeling process. Radiopharmacy staff are accustomed to such procedures in the daily preparation of 99mTc radiopharmaceuticals. Currently, chelating agents used in 68Ga radiopharmaceuticals do not meet this ideal. The aim of this study was to develop and evaluate preclinically a 68Ga radiotracer for imaging PSMA expression that could be radiolabeled simply by addition of 68Ga generator eluate to a cold kit. Methods: A conjugate of a tris(hydroxypyridinone) (THP) chelator with the established urea-based PSMA inhibitor was synthesized and radiolabeled with 68Ga by adding generator eluate directly to a vial containing the cold precursors THP-PSMA and sodium bicarbonate, with no further manipulation. It was analyzed after 5 min by instant thin-layer chromatography and high-performance liquid chromatography. The product was subjected to in vitro studies to determine PSMA affinity using PSMA-expressing DU145-PSMA cells, with their nonexpressing analog DU145 as a control. In vivo PET imaging and ex vivo biodistribution studies were performed in mice bearing xenografts of the same cell lines, comparing 68Ga-THP-PSMA with 68Ga-HBED-CC-PSMA. Results: Radiolabeling was complete (>95%) within 5 min at room temperature, showing a single radioactive species by high-performance liquid chromatography that was stable in human serum for more than 6 h and showed specific binding to PSMA-expressing cells (concentration giving 50% inhibition of 361 ± 60 nM). In vivo PET imaging showed specific uptake in PSMA-expressing tumors, reaching 5.6 ± 1.2 percentage injected dose per cubic centimeter at 40-60 min and rapid clearance from blood to kidney and bladder. The tumor uptake, biodistribution, and pharmacokinetics were not significantly different from those of 68Ga-HBED-CC-PSMA except for reduced uptake in the spleen. Conclusion:68Ga-THP-PSMA has equivalent imaging properties but greatly simplified radiolabeling compared with other 68Ga-PSMA conjugates. THP offers the prospect of rapid, simple, 1-step, room-temperature syringe-and-vial radiolabeling of 68Ga radiopharmaceuticals.
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Affiliation(s)
- Jennifer D Young
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Vincenzo Abbate
- Institute of Pharmaceutical Science, King's College London, London, United Kingdom
| | - Cinzia Imberti
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Levente K Meszaros
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Michelle T Ma
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Samantha Y A Terry
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Robert C Hider
- Institute of Pharmaceutical Science, King's College London, London, United Kingdom
| | - Greg E Mullen
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
| | - Philip J Blower
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom; and
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38
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Farkas E, Nagel J, Waldron BP, Parker D, Tóth I, Brücher E, Rösch F, Baranyai Z. Equilibrium, Kinetic and Structural Properties of Gallium(III) and Some Divalent Metal Complexes Formed with the New DATA m and DATA 5m Ligands. Chemistry 2017; 23:10358-10371. [PMID: 28504822 DOI: 10.1002/chem.201701508] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Indexed: 11/08/2022]
Abstract
The development of 68 Ge/68 Ga generators has made the positron-emitting 68 Ga isotope widely accessible and raised interest in new chelate complexes of Ga3+ . The hexadentate 1,4-di(acetate)-6-methyl[amino(methyl)acetate]perhydro-1,4-diazepane (DATAm ) ligand and its bifunctional analogue, 1,4-di(acetate)-6-pentanoic acid[amino(methyl)acetate]perhydro-1,4-diazepane (DATA5m ), rapidly form complexes with 68 Ga in high radiochemical yield. The stability constants of DATAm and DATA5m complexes formed with Ga3+ , Zn2+ , Cu2+ , Mn2+ and Ca2+ have been determined by using pH potentiometry, spectrophotometry (Cu2+ ) and 1 H and 71 Ga NMR spectroscopy (Ga3+ ). The stability constants of Ga(DATAm ) and Ga(DATA5m ) complexes are slightly higher than those of Ga(AAZTA). The species distribution calculations indicated the predominance of Ga(L)OH mixed-hydroxo complexes at physiological pH. The 1 H and 71 Ga NMR spectroscopy studies provided information about the coordinated functional groups of ligands and on the kinetics of exchange between the Ga(L) and Ga(L)OH complexes. The transmetalation reactions between the Ga(L) complexes and Cu2+ citrate (6<pH<8.5) occur through both spontaneous and OH- -assisted dissociation of the Ga(L)OH species. At pH 7.4 and 25 °C, the half-lives of the dissociation of Ga(DATAm ), Ga(DATA5m ) and Ga(AAZTA) were 11, 44 and 24 h, respectively. Similar half-lives have been obtained for the ligand-exchange reactions between the Ga(L)OH complexes and transferrin. The equilibrium and kinetic data indicate that the Ga(DATA5m ) complex is a good 68 Ga-based radiodiagnostic candidate.
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Affiliation(s)
- Edit Farkas
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, 4032, Debrecen, Hungary
| | - Johannes Nagel
- Institute of Nuclear Chemistry, University of Mainz, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany
| | - Bradley P Waldron
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - David Parker
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - Imre Tóth
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, 4032, Debrecen, Hungary
| | - Ernő Brücher
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, 4032, Debrecen, Hungary
| | - Frank Rösch
- Institute of Nuclear Chemistry, University of Mainz, Fritz-Strassmann-Weg 2, 55128, Mainz, Germany
| | - Zsolt Baranyai
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, 4032, Debrecen, Hungary.,Present address: Bracco Imaging-CRB/Trieste, Area Science Park. Ed. Q, SS 14, km 163.5, 34149, Basovizza Trieste, Italy
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39
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Pfannkuchen N, Meckel M, Bergmann R, Bachmann M, Bal C, Sathekge M, Mohnike W, Baum RP, Rösch F. Novel Radiolabeled Bisphosphonates for PET Diagnosis and Endoradiotherapy of Bone Metastases. Pharmaceuticals (Basel) 2017; 10:ph10020045. [PMID: 28524118 PMCID: PMC5490402 DOI: 10.3390/ph10020045] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/03/2017] [Accepted: 05/05/2017] [Indexed: 01/25/2023] Open
Abstract
Bone metastases, often a consequence of breast, prostate, and lung carcinomas, are characterized by an increased bone turnover, which can be visualized by positron emission tomography (PET), as well as single-photon emission computed tomography (SPECT). Bisphosphonate complexes of 99mTc are predominantly used as SPECT tracers. In contrast to SPECT, PET offers a higher spatial resolution and, owing to the 68Ge/68Ga generator, an analog to the established 99mTc generator exists. Complexation of Ga(III) requires the use of chelators. Therefore, DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), NOTA (1,4,7-triazacyclododecane-1,4,7-triacetic acid), and their derivatives, are often used. The combination of these macrocyclic chelators and bisphosphonates is currently studied worldwide. The use of DOTA offers the possibility of a therapeutic application by complexing the β-emitter 177Lu. This overview describes the possibility of diagnosing bone metastases using [68Ga]Ga-BPAMD (68Ga-labeled (4-{[bis-(phosphonomethyl))carbamoyl]methyl}-7,10-bis(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl)acetic acid) as well as the successful application of [177Lu]Lu-BPAMD for therapy and the development of new diagnostic and therapeutic tools based on this structure. Improvements concerning both the chelator and the bisphosphonate structure are illustrated providing new 68Ga- and 177Lu-labeled bisphosphonates offering improved pharmacological properties.
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Affiliation(s)
- Nina Pfannkuchen
- Institute of Nuclear Chemistry, Johannes Gutenberg University Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz, Germany.
| | - Marian Meckel
- Institute of Nuclear Chemistry, Johannes Gutenberg University Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz, Germany.
| | - Ralf Bergmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstrasse 400, 01328 Dresden, Germany.
| | - Michael Bachmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstrasse 400, 01328 Dresden, Germany.
- University Cancer Center (UCC) Carl Gustav Carus, Tumorimmunology, Technical University Dresden, Fetscherstr. 74, 01307 Dresden, Germany.
| | - Chandrasekhar Bal
- Department of Nuclear Medicine & PET, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
| | - Mike Sathekge
- Department of Nuclear Medicine, University of Pretoria & Steve Biko Academic Hospital, Private Bag X169, Pretoria 0001, South Africa.
| | - Wolfgang Mohnike
- Diagnostisch Therapeutisches Zentrum, DTZ am Frankfurter Tor, Kadiner Straße 23, 10243 Berlin, Germany.
| | - Richard P Baum
- Department of Nuclear Medicine, Center for PET/CT, Zentralklinik Bad Berka, Robert-Koch-Allee 9, 99438 Bad Berka, Germany.
| | - Frank Rösch
- Institute of Nuclear Chemistry, Johannes Gutenberg University Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz, Germany.
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40
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Imberti C, Terry SYA, Cullinane C, Clarke F, Cornish GH, Ramakrishnan NK, Roselt P, Cope AP, Hicks RJ, Blower PJ, Ma MT. Enhancing PET Signal at Target Tissue in Vivo: Dendritic and Multimeric Tris(hydroxypyridinone) Conjugates for Molecular Imaging of α vβ 3 Integrin Expression with Gallium-68. Bioconjug Chem 2017; 28:481-495. [PMID: 27966893 PMCID: PMC5314429 DOI: 10.1021/acs.bioconjchem.6b00621] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 11/23/2016] [Indexed: 12/12/2022]
Abstract
Tris(hydroxypyridinone) chelators conjugated to peptides can rapidly complex the positron-emitting isotope gallium-68 (68Ga) under mild conditions, and the resulting radiotracers can delineate peptide receptor expression at sites of diseased tissue in vivo. We have synthesized a dendritic bifunctional chelator containing nine 1,6-dimethyl-3-hydroxypyridin-4-one groups (SCN-HP9) that can coordinate up to three Ga3+ ions. This derivative has been conjugated to a trimeric peptide (RGD3) containing three peptide groups that target the αvβ3 integrin receptor. The resulting dendritic compound, HP9-RGD3, can be radiolabeled in 97% radiochemical yield at a 3-fold higher specific activity than its homologues HP3-RGD and HP3-RGD3 that contain only a single metal binding site. PET scanning and biodistribution studies show that [68Ga(HP9-RGD3)] demonstrates higher receptor-mediated tumor uptake in animals bearing U87MG tumors that overexpress αvβ3 integrin than [68Ga(HP3-RGD)] and [68Ga(HP3-RGD3)]. However, concomitant nontarget organ retention of [68Ga(HP9-RGD3)] results in low tumor to nontarget organ contrast in PET images. On the other hand, the trimeric peptide homologue containing a single tris(hydroxypyridinone) chelator, [68Ga(HP3-RGD3)], clears nontarget organs and exhibits receptor-mediated uptake in mice bearing tumors and in mice with induced rheumatoid arthritis. PET imaging with [68Ga(HP3-RGD3)] enables clear delineation of αvβ3 integrin receptor expression in vivo.
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Affiliation(s)
- Cinzia Imberti
- King’s College
London, Division of Imaging
Sciences and Biomedical Engineering, Fourth
Floor Lambeth Wing, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Samantha Y. A. Terry
- King’s College
London, Division of Imaging
Sciences and Biomedical Engineering, Fourth
Floor Lambeth Wing, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Carleen Cullinane
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Fiona Clarke
- King’s College
London, Academic Department of Rheumatology,
Centre for Molecular and Cellular Biology of Inflammation, Faculty
of Life Sciences and Medicine, London SE1 1UL, United Kingdom
| | - Georgina H. Cornish
- King’s College
London, Academic Department of Rheumatology,
Centre for Molecular and Cellular Biology of Inflammation, Faculty
of Life Sciences and Medicine, London SE1 1UL, United Kingdom
| | - Nisha K. Ramakrishnan
- King’s College
London, Division of Imaging
Sciences and Biomedical Engineering, Fourth
Floor Lambeth Wing, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Peter Roselt
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
| | - Andrew P. Cope
- King’s College
London, Academic Department of Rheumatology,
Centre for Molecular and Cellular Biology of Inflammation, Faculty
of Life Sciences and Medicine, London SE1 1UL, United Kingdom
| | - Rodney J. Hicks
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Philip J. Blower
- King’s College
London, Division of Imaging
Sciences and Biomedical Engineering, Fourth
Floor Lambeth Wing, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Michelle T. Ma
- King’s College
London, Division of Imaging
Sciences and Biomedical Engineering, Fourth
Floor Lambeth Wing, St Thomas’ Hospital, London SE1 7EH, United Kingdom
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41
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Price TW, Gallo J, Kubíček V, Böhmová Z, Prior TJ, Greenman J, Hermann P, Stasiuk GJ. Amino acid based gallium-68 chelators capable of radiolabeling at neutral pH. Dalton Trans 2017; 46:16973-16982. [DOI: 10.1039/c7dt03398b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we show a flexible synthesis for bifunctional chelators based on amino acids that rapidly complex 68Ga under physiological conditions.
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Affiliation(s)
- Thomas W. Price
- School of Life Sciences
- Department of Biomedical Sciences
- University of Hull
- Hull
- UK
| | - Juan Gallo
- Advanced (magnetic) Theranostic Nanostructures Lab
- International Iberian Nanotechnology Laboratory
- 4715-330 Braga
- Portugal
| | - Vojtěch Kubíček
- Department of Inorganic Chemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Zuzana Böhmová
- Department of Inorganic Chemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Timothy J. Prior
- Chemistry
- School of Mathematical and Physical Sciences
- University of Hull
- Hull
- UK
| | - John Greenman
- School of Life Sciences
- Department of Biomedical Sciences
- University of Hull
- Hull
- UK
| | - Petr Hermann
- Department of Inorganic Chemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Graeme J. Stasiuk
- School of Life Sciences
- Department of Biomedical Sciences
- University of Hull
- Hull
- UK
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42
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Nock BA, Kaloudi A, Nagel J, Sinnes JP, Roesch F, Maina T. Novel bifunctional DATA chelator for quick access to site-directed PET 68Ga-radiotracers: preclinical proof-of-principle with [Tyr3]octreotide. Dalton Trans 2017; 46:14584-14590. [DOI: 10.1039/c7dt01684k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Comparison of 68Ga-DATA-TOC vs. 68Ga-DOTA-TOC in sst2-positive cells and tumor-bearing mice revealed the suitability of DATA for easy access to 68Ga-labeled vectors.
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Affiliation(s)
- Berthold A. Nock
- Molecular Radiopharmacy
- INRASTES
- NCSR “Demokritos”
- GR-15310 Athens
- Greece
| | | | - Johannes Nagel
- Institute of Nuclear Chemistry
- Johannes Gutenberg-University of Mainz
- D-55126 Mainz
- Germany
| | - Jean-Philippe Sinnes
- Institute of Nuclear Chemistry
- Johannes Gutenberg-University of Mainz
- D-55126 Mainz
- Germany
| | - Frank Roesch
- Institute of Nuclear Chemistry
- Johannes Gutenberg-University of Mainz
- D-55126 Mainz
- Germany
| | - Theodosia Maina
- Molecular Radiopharmacy
- INRASTES
- NCSR “Demokritos”
- GR-15310 Athens
- Greece
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43
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Spang P, Herrmann C, Roesch F. Bifunctional Gallium-68 Chelators: Past, Present, and Future. Semin Nucl Med 2016; 46:373-94. [DOI: 10.1053/j.semnuclmed.2016.04.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Seemann J, Waldron B, Parker D, Roesch F. DATATOC: a novel conjugate for kit-type 68Ga labelling of TOC at ambient temperature. EJNMMI Radiopharm Chem 2016; 1:4. [PMID: 29564381 PMCID: PMC5843802 DOI: 10.1186/s41181-016-0007-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 02/12/2016] [Indexed: 11/10/2022] Open
Abstract
Background The widespread acceptance and application of 68Ga-PET depends on our ability to develop radiopharmaceuticals that can be prepared in a convenient and suitable manner. A kit-type labelling protocol provides such characteristics and requires chelators that can be radiolabelled under exceptionally mild conditions. Recently the DATA chelators have been introduced that fulfil these requirements. In continuing their development, the synthesis and radiolabelling of the first DATA bifunctional chelator (BFC) and peptide conjugate are described. Results A BFC derived from the DATA ligand (2,2'-(6-((carboxymethyl)amino)-1,4-diazepane-1,4-diyl)diacetic acid) has been synthesised in five steps from simple building blocks, with an overall yield of 8 %. DATAM5-3tBu (5-[1,4-Bis-tert-butoxycarbonylmethyl-6-(tert-butoxycarbonylmethyl-methyl-amino)-[1, 4]diazepan-6-yl]-pentanoic acid) has been coupled to [DPhe1][Tyr3]-octreotide (TOC) and the resulting peptide conjugate (DATATOC) radiolabelled with purified 68Ga derived via four different 68Ge/68Ga generator post-processing (PP) methods. The stability and lipophilicity of the radiotracer have been assessed and a kit-type formulation for radiolabelling evaluated. 68Ga-DATATOC has been prepared with a > 95 % radiochemical yield (RCY) within 1 (fractionated and acetone-PP) and 10 min (ethanol- and NaCl-PP) at 23 °C (pH 4.2-4.9, 13 nmol). The radiolabelled peptide is stable in the presence of human serum. Lipophilicity of 68Ga-DATATOC was calculated as logP = -3.2 ± 0.3, with a HPLC retention time (tR = 10.4 min) similar to 68Ga-DOTATOC (logP = -2.9 ± 0.4, tR = 10.3 min). Kit-type labelling from a lyophilised solid using acetone-PP based labelling achieves > 95 % RCY in 10 min at 23 °C. Conclusions The favourable labelling properties of the DATA chelators have been retained for DATATOC. High radiochemical purity can be achieved at 23 °C in less than 1 min and from a kit formulation. The speed, reliability, ease, flexibility and simplicity with which 68Ga-DATATOC can be prepared makes it a very attractive alternative to current standards.
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Affiliation(s)
- Johanna Seemann
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Fritz-Strassmann-Weg 2, 55128 Mainz, Germany
| | - Bradley Waldron
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Fritz-Strassmann-Weg 2, 55128 Mainz, Germany
| | - David Parker
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE UK
| | - Frank Roesch
- Institute of Nuclear Chemistry, Johannes Gutenberg University, Fritz-Strassmann-Weg 2, 55128 Mainz, Germany
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45
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Wu Z, Zha Z, Choi SR, Plössl K, Zhu L, Kung HF. New (68)Ga-PhenA bisphosphonates as potential bone imaging agents. Nucl Med Biol 2016; 43:360-71. [PMID: 27260777 DOI: 10.1016/j.nucmedbio.2016.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 02/19/2016] [Accepted: 03/07/2016] [Indexed: 12/11/2022]
Abstract
INTRODUCTION In vivo positron emission tomography (PET) imaging of the bone using [(68)Ga]bisphosphonates may be a valuable tool for cancer diagnosis and monitoring therapeutic treatment. We have developed new [(68)Ga]bisphosphonates based on the chelating group, AAZTA (6-[bis(hydroxycarbonyl-methyl)amino]-1,4-bis(hydroxycarbonyl methyl)-6-methylperhydro-1,4-diazepine). METHOD Phenoxy derivative of AAZTA (2,2'-(6-(bis(carboxymethyl)amino)-6-((4-(2-carboxyethyl)phenoxy)methyl)-1,4-diazepane-1,4-diyl)diacetic acid), PhenA, 2, containing a bisphosphonate group (PhenA-BPAMD, 3, and PhenA-HBP, 4) was prepared. Labeling of these chelating agents with (68)Ga was evaluated. RESULTS The ligands reacted rapidly in a sodium acetate buffer with [(68)Ga]GaCl3 eluted from a commercially available (68)Ge/(68)Ga generator (pH4, >95% labeling at room temperature in 5min) to form [(68)Ga]PhenA-BPAMD, 3, and [(68)Ga]PhenA-HBP, 4. The improved labeling condition negates the need for further purification. The (68)Ga bisphosphonate biodistribution and autoradiography of bone sections in normal mice after an iv injection showed excellent bone uptake. CONCLUSION New (68)Ga labeled bisphosphonates may be useful as in vivo bone imaging agents in conjunction with positron emission tomography (PET).
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Affiliation(s)
- Zehui Wu
- Five Eleven Pharma Inc., Philadelphia, PA 19104, USA
| | - Zhihao Zha
- Five Eleven Pharma Inc., Philadelphia, PA 19104, USA
| | - Seok Rye Choi
- Five Eleven Pharma Inc., Philadelphia, PA 19104, USA
| | - Karl Plössl
- Five Eleven Pharma Inc., Philadelphia, PA 19104, USA
| | - Lin Zhu
- Five Eleven Pharma Inc., Philadelphia, PA 19104, USA
| | - Hank F Kung
- Five Eleven Pharma Inc., Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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46
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Vágner A, D'Alessandria C, Gambino G, Schwaiger M, Aime S, Maiocchi A, Tóth I, Baranyai Z, Tei L. A rigidified AAZTA-like ligand as efficient chelator for68Ga radiopharmaceuticals. ChemistrySelect 2016. [DOI: 10.1002/slct.201500051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Adrienn Vágner
- Department of Inorganic and Analytical Chemistry; University of Debrecen; H-4032 Debrecen Egyetem tér 1. Hungary
| | - Calogero D'Alessandria
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar; Technische Universität München; Ismaningerstr. 22 81675 Munich Germany
| | - Giuseppe Gambino
- Dipartimento di Scienze e Innovazione Tecnologica (DiSIT); Università degli Studi del Piemonte Orientale “A. Avogadro”; Viale T. Michel 11 I-15121 Alessandria Italy
| | - Markus Schwaiger
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar; Technische Universität München; Ismaningerstr. 22 81675 Munich Germany
| | - Silvio Aime
- Department of Molecular Biotechnology and Health Sciences; Molecular Imaging Center, University of Torino; Via Nizza 52 I-10126 Torino Italy
| | - Alessandro Maiocchi
- Centro Ricerche Bracco, Bracco Imaging Spa; Via Ribes 5 I-10010 Colleretto Giacosa Italy
| | - Imre Tóth
- Department of Inorganic and Analytical Chemistry; University of Debrecen; H-4032 Debrecen Egyetem tér 1. Hungary
| | - Zsolt Baranyai
- Department of Inorganic and Analytical Chemistry; University of Debrecen; H-4032 Debrecen Egyetem tér 1. Hungary
| | - Lorenzo Tei
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar; Technische Universität München; Ismaningerstr. 22 81675 Munich Germany
- Dipartimento di Scienze e Innovazione Tecnologica (DiSIT); Università degli Studi del Piemonte Orientale “A. Avogadro”; Viale T. Michel 11 I-15121 Alessandria Italy
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47
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Burke BP, Seemann J, Archibald SJ. Advanced Chelator Design for Metal Complexes in Imaging Applications. ADVANCES IN INORGANIC CHEMISTRY 2016. [DOI: 10.1016/bs.adioch.2015.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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48
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Poty S, Désogère P, Šimeček J, Bernhard C, Goncalves V, Goze C, Boschetti F, Notni J, Wester HJ, Denat F. MA-NOTMP: A Triazacyclononane Trimethylphosphinate Based Bifunctional Chelator for Gallium Radiolabelling of Biomolecules. ChemMedChem 2015; 10:1475-9. [DOI: 10.1002/cmdc.201500198] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 12/20/2022]
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