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Zhang M, Kang F, Xing T, Wang J, Ma T, Li G, Quan Z, Yang W, Chen X, Wang J. First-in-human validation of enzymolysis clearance strategy for decreasing renal radioactivity using modified [ 68Ga]Ga-HER2 Affibody. Eur J Nucl Med Mol Imaging 2024; 51:1713-1724. [PMID: 38216779 DOI: 10.1007/s00259-023-06584-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 12/11/2023] [Indexed: 01/14/2024]
Abstract
PURPOSE Enzymolysis clearance strategy, characterized by releasing the non-reabsorbable radioactive fragment under the specific cleavage of enzymes, is confirmed to be a safe and effective way to reduce the renal radioactivity accumulation in mice. However, the effectiveness of this strategy in humans remains unknown. Human epidermal growth factor receptor 2 (HER2) is overexpressed in various types of tumors, and radiolabeled HER2 Affibody is believed to be an attractive tool for HER2-targeted theranostics. However, its wide application is limited by the high and persistent renal uptake. In this study, we intend to validate the effectiveness of enzymolysis clearance strategy in reducing renal accumulation by using a modified HER2 Affibody. MATERIALS AND METHODS A new HER2 Affibody ligand, NOTA-MVK-ZHER2:2891, containing a cleavable Met-Val-Lys (MVK) linker was synthesized and labeled with 68Ga. The microPET imaging study was performed in SKOV-3 tumor mice to assess the uptakes of the control ligand and the MVK one in tumors and kidneys. Seven healthy volunteers were included for biodistribution and dosimetric studies with both the control and MVK ligands performed 1 week apart. Urine and blood samples from healthy volunteers were collected for in vivo metabolism study of the two ligands. Four HER2-positive and two HER2-negative patients were recruited for [68Ga]Ga-NOTA-MVK-ZHER2:2891 PET/CT imaging at 2 and 4 h post-injection (p.i.). RESULTS [68Ga]Ga-NOTA-MVK-ZHER2:2891 was stable both in PBS and in mouse serum. MicroPET images showed that the tumor uptake of [68Ga]Ga-NOTA-MVK-ZHER2:2891 was comparable to that of [68Ga]Ga-NOTA-ZHER2:2891 at all the time points, while the kidney uptake was significantly reduced 40 min p.i. (P < 0.05). The biodistribution study in healthy volunteers showed that the kidney uptake of MVK ligand was significantly lower than that of the control ligand at 1 h p.i. (P < 0.05), with the SUVmean of 34.3 and 45.8, respectively, while the uptakes of the two ligands in the other organs showed negligible difference. The effective doses of the MVK ligand and the control one were 26.1 and 28.7 µSv/MBq, respectively. The enzymolysis fragment of [68Ga]Ga-NOTA-Met-OH was observed in the urine samples of healthy volunteers injected with the MVK ligand, indicating that the enzymolysis clearance strategy worked in humans. The PET/CT study of patients showed that the range of SUVmax of HER2-positive lesions was 9.4-21, while that of HER2-negative lesions was 2.7-6.2, which suggested that the MVK modification did not affect the ability of ZHER2:2891 structure to bind with HER2. CONCLUSION We for the first time demonstrated that enzymolysis clearance strategy can effectively reduce renal radioactivity accumulation in humans. This strategy is expected to decrease renal radiation dose of peptide and small protein-based radiotracers, especially in the field of radionuclide therapy.
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Affiliation(s)
- Mingru Zhang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Fei Kang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Tong Xing
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Junling Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Taoqi Ma
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Guiyu Li
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Zhiyong Quan
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Weidong Yang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China
| | - Xiaoyuan Chen
- Departments of Diagnostic Radiology, Surgery, Chemical and Biomolecular Engineering, and Biomedical Engineering, Yong Loo Lin School of Medicine and Faculty of Engineering, National University of Singapore, Singapore, 119074, Singapore.
- Clinical Imaging Research Centre, Centre for Translational Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117599, Singapore.
- Nanomedicine Translational Research Program, NUS Center for Nanomedicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.
| | - Jing Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, Shannxi, China.
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Lundmark F, Vorobyeva A, Liu Y, Lindbo S, Xu T, Oroujeni M, Rinne SS, Rosenström U, Garousi J. Reduction of renal activity retention of radiolabeled albumin binding domain‑derived affinity proteins using a non‑residualizing label strategy compared with a cleavable glycine‑leucine‑glycine‑lysine‑linker. Mol Med Rep 2024; 29:32. [PMID: 38186305 PMCID: PMC10784736 DOI: 10.3892/mmr.2023.13155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 11/29/2023] [Indexed: 01/09/2024] Open
Abstract
The feasibility of targeted imaging and therapy using radiolabeled albumin‑binding domain‑derived affinity proteins (ADAPTs) has been demonstrated. However, high renal uptake of radioactivity limits the maximum tolerated dose. Successful reduction of renal retention of radiolabeled Fab fragments has been demonstrated by incorporating a cleavable linker between the targeting agent and the radiometal chelator. The present study investigated if the introduction of a glycine‑leucine‑glycine‑lysine (GLGK)‑linker would reduce the kidney uptake of radiolabeled ADAPT6 and also compared it with the non‑residualizing [125I]I‑[(4‑hydroxyphenyl)ethyl]maleimide ([125I]I‑HPEM) labeling strategy. GLGK was site‑specifically coupled to human epidermal growth factor receptor 2 (HER2)‑targeting ADAPT6. Conjugates without the cleavable linker were used as controls and all constructs were labeled with lutetium‑177 (177Lu). [125I]I‑HPEM was coupled to ADAPT6 at the C‑terminus. Biodistribution of all constructs was evaluated in NMRI mice 4 h after injection. Specific binding to HER2‑expressing cells in vitro was demonstrated for all constructs. No significant difference in kidney uptake was observed between the [177Lu]Lu‑2,2',2",2"'‑(1,4,7,10‑tetraazacyclododecane‑1,4,7,10‑tetrayl)tetraacetic acid‑GLGK‑conjugates and the controls. The renal activity of [125I]I‑HPEM‑ADAPT6 was significantly lower compared with all other constructs. In conclusion, the incorporation of the cleavable GLGK‑linker did not result in lower renal retention. Therefore, the present study emphasized that, in order to achieve a reduction of renal retention, alternative molecular design strategies may be required for different targeting agents.
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Affiliation(s)
- Fanny Lundmark
- Department of Medicinal Chemistry, Uppsala University, 75123 Uppsala, Sweden
| | - Anzhelika Vorobyeva
- Department of Immunology, Genetics and Pathology, Uppsala University, 75185 Uppsala, Sweden
| | - Yongsheng Liu
- Department of Immunology, Genetics and Pathology, Uppsala University, 75185 Uppsala, Sweden
| | - Sarah Lindbo
- Department of Protein Technology, Royal Institute of Technology, 10691 Stockholm, Sweden
| | - Tianqi Xu
- Department of Immunology, Genetics and Pathology, Uppsala University, 75185 Uppsala, Sweden
| | - Maryam Oroujeni
- Department of Immunology, Genetics and Pathology, Uppsala University, 75185 Uppsala, Sweden
| | - Sara S. Rinne
- Department of Medicinal Chemistry, Uppsala University, 75123 Uppsala, Sweden
| | - Ulrika Rosenström
- Department of Medicinal Chemistry, Uppsala University, 75123 Uppsala, Sweden
| | - Javad Garousi
- Department of Immunology, Genetics and Pathology, Uppsala University, 75185 Uppsala, Sweden
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Trachsel B, Valpreda G, Lutz A, Schibli R, Mu L, Béhé M. Reducing kidney uptake of radiolabelled exendin-4 using variants of the renally cleavable linker MVK. EJNMMI Radiopharm Chem 2023; 8:21. [PMID: 37665477 PMCID: PMC10477158 DOI: 10.1186/s41181-023-00206-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 08/21/2023] [Indexed: 09/05/2023] Open
Abstract
BACKGROUND Peptidic radiotracers are preferentially excreted through the kidneys, which often results in high persistent renal retention of radioactivity, limiting or even preventing therapeutic clinical translation of these radiotracers. Exendin-4, which targets the glucagon-like-peptide 1 receptor (GLP-1R) overexpressed in insulinomas and in congenital hyperinsulinism, is an example thereof. The use of the tripeptide MVK, which is readily cleaved between methionine and valine by neprilysin at the renal brush border membrane, already showed promising results in reducing kidney uptake as reported in the literature. Based on our previous findings we were interested how linker variants with multiple copies of the MV-motive influence renal washout of radiolabelled exendin-4. RESULTS Three exendin-4 derivatives, carrying either one MVK, a MV-MVK or a MVK-MVK linker were synthesized and compared to a reference compound lacking a cleavable linker. In vivo results of a biodistribution in GLP-1R overexpressing tumour bearing mice at 24 h post-injection demonstrated a significant reduction (at least 57%) of renal retention of all 111In-labeled exendin-4 compounds equipped with a cleavable linker compared to the reference compound. While the insertion of the single linker MVK led to a reduction in kidney uptake of 70%, the dual approach with the linker MV-MVK slightly, but not significantly enhanced this effect, with 77% reduction in kidney uptake compared to the reference. In vitro IC50 and cell uptake studies were conducted and demonstrated that though the cleavable linkers negatively influenced the affinity towards the GLP-1R, cell uptake remained largely unaffected, except for the MV-MVK cleavable linker conjugate, which displayed lower cell uptake than the other compounds. Importantly, the tumour uptake in the biodistribution study was not significantly affected with 2.9, 2.5, 3.2 and 1.5% iA/g for radiolabelled Ex4, MVK-Ex4, MV-MVK-Ex4 and MVK-MVK-Ex4, respectively. CONCLUSION Cleavable linkers are highly efficient in reducing the radioactivity burden in the kidney. Though the dual linker approach using the instillation of MV-MVK or MVK-MVK between exendin-4 and the radiometal chelator did not significantly outperform the single cleavable linker MVK, further structural optimization or the combination of different cleavable linkers could be a stepping stone in reducing radiation-induced nephrotoxicity.
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Affiliation(s)
- Belinda Trachsel
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Giulia Valpreda
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Alexandra Lutz
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Linjing Mu
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Martin Béhé
- Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland.
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Wilbs J, Raavé R, Boswinkel M, Glendorf T, Rodríguez D, Fernandes EF, Heskamp S, Bjørnsdottir I, Gustafsson MBF. New Long-Acting [ 89Zr]Zr-DFO GLP-1 PET Tracers with Increased Molar Activity and Reduced Kidney Accumulation. J Med Chem 2023; 66:7772-7784. [PMID: 36995126 PMCID: PMC10292199 DOI: 10.1021/acs.jmedchem.2c02073] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Indexed: 03/31/2023]
Abstract
Positron emission tomography (PET) imaging is used in drug development to noninvasively measure biodistribution and receptor occupancy. Ideally, PET tracers retain target binding and biodistribution properties of the investigated drug. Previously, we developed a zirconium-89 PET tracer based on a long-circulating glucagon-like peptide 1 receptor agonist (GLP-1RA) using desferrioxamine (DFO) as a chelator. Here, we aimed to develop an improved zirconium-89-labeled GLP-1RA with increased molar activity to increase the uptake in low receptor density tissues, such as brain. Furthermore, we aimed at reducing tracer accumulation in the kidneys. Introducing up to four additional Zr-DFOs resulted in higher molar activity and stability, while retaining potency. Branched placement of DFOs was especially beneficial. Tracers with either two or four DFOs had similar biodistribution as the tracer with one DFO in vivo, albeit increased kidney and liver uptake. Reduced kidney accumulation was achieved by introducing an enzymatically cleavable Met-Val-Lys (MVK) linker motif between the chelator and the peptide.
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Affiliation(s)
- Jonas Wilbs
- Global
Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - René Raavé
- Department
of Medical Imaging−Nuclear Medicine, Radboudumc, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
| | - Milou Boswinkel
- Department
of Medical Imaging−Nuclear Medicine, Radboudumc, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
| | - Tine Glendorf
- Global
Drug Discovery, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - David Rodríguez
- Digital
Science and Innovation, Novo Nordisk A/S, 2760 Måløv, Denmark
| | | | - Sandra Heskamp
- Department
of Medical Imaging−Nuclear Medicine, Radboudumc, Radboud Institute for Molecular Life Sciences, 6500 HB Nijmegen, The Netherlands
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Murce E, Beekman S, Spaan E, Handula M, Stuurman D, de Ridder C, Seimbille Y. Preclinical Evaluation of a PSMA-Targeting Homodimer with an Optimized Linker for Imaging of Prostate Cancer. Molecules 2023; 28:molecules28104022. [PMID: 37241763 DOI: 10.3390/molecules28104022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Prostate-specific membrane antigen (PSMA) targeting radiopharmaceuticals have been successfully used for diagnosis and therapy of prostate cancer. Optimization of the available agents is desirable to improve tumor uptake and reduce side effects to non-target organs. This can be achieved, for instance, via linker modifications or multimerization approaches. In this study, we evaluated a small library of PSMA-targeting derivatives with modified linker residues, and selected the best candidate based on its binding affinity to PSMA. The lead compound was coupled to a chelator for radiolabeling, and subject to dimerization. The resulting molecules, 22 and 30, were highly PSMA specific (IC50 = 1.0-1.6 nM) and stable when radiolabeled with indium-111 (>90% stable in PBS and mouse serum up to 24 h). Moreover, [111In]In-30 presented a high uptake in PSMA expressing LS174T cells, with 92.6% internalization compared to 34.1% for PSMA-617. Biodistribution studies in LS174T mice xenograft models showed that [111In]In-30 had a higher tumor and kidney uptake compared to [111In]In-PSMA-617, but increasing T/K and T/M ratios at 24 h p.i. Tumors could be clearly visualized at 1 h p.i. by SPECT/CT after administration of [111In]In-22 and [111In]In-PSMA-617, while [111In]In-30 showed a clear signal at later time-points (e.g., 24 h p.i.).
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Affiliation(s)
- Erika Murce
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, 3015 GD Rotterdam, The Netherlands
| | - Savanne Beekman
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, 3015 GD Rotterdam, The Netherlands
| | - Evelien Spaan
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, 3015 GD Rotterdam, The Netherlands
| | - Maryana Handula
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, 3015 GD Rotterdam, The Netherlands
| | - Debra Stuurman
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, 3015 GD Rotterdam, The Netherlands
| | - Corrina de Ridder
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, 3015 GD Rotterdam, The Netherlands
| | - Yann Seimbille
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, 3015 GD Rotterdam, The Netherlands
- Life Sciences Division, TRIUMF, Vancouver, BC V6T 2A3, Canada
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Barta P, Nachtigal P, Maixnerova J, Zemankova L, Trejtnar F. Validation of Freshly Isolated Rat Renal Cells as a Tool for Preclinical Assessment of Radiolabeled Receptor-Specific Peptide Uptake in the Kidney. Pharmaceuticals (Basel) 2023; 16:ph16050696. [PMID: 37242479 DOI: 10.3390/ph16050696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/19/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
The synthetic analogs of regulatory peptides radiolabeled with adequate radionuclides are perspective tools in nuclear medicine. However, undesirable uptake and retention in the kidney limit their application. Specific in vitro methods are used to evaluate undesirable renal accumulation. Therefore, we investigated the usefulness of freshly isolated rat renal cells for evaluating renal cellular uptake of receptor-specific peptide analogs. Special attention was given to megalin as this transport system is an important contributor to the active renal uptake of the peptides. Freshly isolated renal cells were obtained from native rat kidneys by the collagenase method. Compounds with known accumulation in renal cells were used to verify the viability of cellular transport systems. Megalin expressions in isolated rat renal cells were compared to two other potential renal cell models by Western blotting. Specific tubular cell markers were used to confirm the presence of proximal tubular cells expressing megalin in isolated rat renal cell preparations by immunohistochemistry. Colocalization experiments on isolated rat kidney cells confirmed the presence of proximal tubular cells bearing megalin in preparations. The applicability of the method was tested by an accumulation study with several analogs of somatostatin and gastrin labeled with indium-111 or lutetium-177. Therefore, isolated rat renal cells may be an effective screening tool for in vitro analyses of renal uptake and comparative renal accumulation studies of radiolabeled peptides or other radiolabeled compounds with potential nephrotoxicity.
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Affiliation(s)
- Pavel Barta
- Department of Biophysics and Physical Chemistry, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Petr Nachtigal
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Jana Maixnerova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Lenka Zemankova
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Slechtitelu 27, 78371 Olomouc, Czech Republic
| | - Frantisek Trejtnar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralové, Charles University, Akademika Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
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Funeh CN, Bridoux J, Ertveldt T, De Groof TWM, Chigoho DM, Asiabi P, Covens P, D'Huyvetter M, Devoogdt N. Optimizing the Safety and Efficacy of Bio-Radiopharmaceuticals for Cancer Therapy. Pharmaceutics 2023; 15:pharmaceutics15051378. [PMID: 37242621 DOI: 10.3390/pharmaceutics15051378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/20/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
The precise delivery of cytotoxic radiation to cancer cells through the combination of a specific targeting vector with a radionuclide for targeted radionuclide therapy (TRT) has proven valuable for cancer care. TRT is increasingly being considered a relevant treatment method in fighting micro-metastases in the case of relapsed and disseminated disease. While antibodies were the first vectors applied in TRT, increasing research data has cited antibody fragments and peptides with superior properties and thus a growing interest in application. As further studies are completed and the need for novel radiopharmaceuticals nurtures, rigorous considerations in the design, laboratory analysis, pre-clinical evaluation, and clinical translation must be considered to ensure improved safety and effectiveness. Here, we assess the status and recent development of biological-based radiopharmaceuticals, with a focus on peptides and antibody fragments. Challenges in radiopharmaceutical design range from target selection, vector design, choice of radionuclides and associated radiochemistry. Dosimetry estimation, and the assessment of mechanisms to increase tumor uptake while reducing off-target exposure are discussed.
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Affiliation(s)
- Cyprine Neba Funeh
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
| | - Jessica Bridoux
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
| | - Thomas Ertveldt
- Laboratory for Molecular and Cellular Therapy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Timo W M De Groof
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
| | - Dora Mugoli Chigoho
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
| | - Parinaz Asiabi
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
| | - Peter Covens
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
| | - Matthias D'Huyvetter
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
| | - Nick Devoogdt
- Laboratory for In Vivo Cellular and Molecular Imaging, Department of Medical Imaging, Vrije Universiteit Brussel, Laarbeeklaan 103/K.001, 1090 Brussels, Belgium
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8
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Murce E, de Blois E, van den Berg S, de Jong M, Seimbille Y. Synthesis and radiolabelling of PSMA-targeted derivatives containing GYK/MVK cleavable linkers. ROYAL SOCIETY OPEN SCIENCE 2023; 10:220950. [PMID: 36908985 PMCID: PMC9993039 DOI: 10.1098/rsos.220950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Targeted radionuclide therapy (TRT) is a promising strategy to treat different types of cancer. TRT relies on a targeting vector used to deliver a therapeutic radionuclide specifically to the tumour site. Several low molecular weight ligands targeting the prostate-specific membrane antigen (PSMA) have been synthesized, but their pharmacokinetic properties still need to be optimized. Hereby, we describe the synthesis of new conjugates, featuring the cleavable linkers Gly-Tyr-Lys (GYK) and Met-Val-Lys (MVK), to reduce the dose delivered to the kidneys. Compounds were synthesized by solid-phase peptide synthesis (SPPS) and obtained in greater than 95% chemical purity. Radiolabelling was performed with both In-111 and Lu-177 to validate potential use of the compounds as both imaging and therapeutic agents. Radiochemical purity greater than 80% was obtained for both nuclides, but significant radiolysis was observed for the methionine-containing analogue. The results obtained thus far with the GYK-PSMA conjugate could warrant further biological investigations.
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Affiliation(s)
- Erika Murce
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Erik de Blois
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Sophie van den Berg
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Marion de Jong
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Yann Seimbille
- Department of Radiology and Nuclear Medicine, University Medical Center Rotterdam, Erasmus MC, Rotterdam, The Netherlands
- Erasmus MC Cancer Institute, Rotterdam, The Netherlands
- TRIUMF, Life Sciences Division, Vancouver, Canada
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9
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Brandt F, Ullrich M, Wodtke J, Kopka K, Bachmann M, Löser R, Pietzsch J, Pietzsch HJ, Wodtke R. Enzymological Characterization of 64Cu-Labeled Neprilysin Substrates and Their Application for Modulating the Renal Clearance of Targeted Radiopharmaceuticals. J Med Chem 2023; 66:516-537. [PMID: 36595224 DOI: 10.1021/acs.jmedchem.2c01472] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The applicability of radioligands for targeted endoradionuclide therapy is limited due to radiation-induced toxicity to healthy tissues, in particular to the kidneys as primary organs of elimination. The targeting of enzymes of the renal brush border membrane by cleavable linkers that permit the formation of fast eliminating radionuclide-carrying cleavage fragments gains increasing interest. Herein, we synthesized a small library of 64Cu-labeled cleavable linkers and quantified their substrate potentials toward neprilysin (NEP), a highly abundant peptidase at the renal brush border membrane. This allowed for the derivation of structure-activity relationships, and selected cleavable linkers were attached to the somatostatin receptor subtype 2 ligand [Tyr3]octreotate. Radiopharmacological characterization revealed that a substrate-based targeting of NEP in the kidneys with small peptides entails their premature cleavage in the blood circulation by soluble and endothelium-derived NEP. However, for a kidney-specific targeting of NEP, the additional targeting of albumin in the blood is highlighted.
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Affiliation(s)
- Florian Brandt
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany.,Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, Mommsenstraße 4, 01069Dresden, Germany
| | - Martin Ullrich
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany
| | - Johanna Wodtke
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany
| | - Klaus Kopka
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany.,Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, Mommsenstraße 4, 01069Dresden, Germany.,National Center for Tumor Diseases (NCT) Dresden, University Hospital Carl Gustav Carus, Fetscherstraße 74, 01307Dresden, Germany.,German Cancer Consortium (DKTK), Partner Site Dresden, Fetscherstraße 74, 01307Dresden, Germany
| | - Michael Bachmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany.,National Center for Tumor Diseases (NCT) Dresden, University Hospital Carl Gustav Carus, Fetscherstraße 74, 01307Dresden, Germany
| | - Reik Löser
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany.,Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, Mommsenstraße 4, 01069Dresden, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany.,Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, Mommsenstraße 4, 01069Dresden, Germany
| | - Hans-Jürgen Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany.,Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, Mommsenstraße 4, 01069Dresden, Germany
| | - Robert Wodtke
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328Dresden, Germany
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10
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Dual MVK cleavable linkers effectively reduce renal retention of 111In-fibronectin-binding peptides. Bioorg Med Chem 2022; 73:117040. [DOI: 10.1016/j.bmc.2022.117040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/21/2022] [Accepted: 09/23/2022] [Indexed: 11/21/2022]
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11
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Lau J, Lee H, Rousseau J, Bénard F, Lin KS. Application of Cleavable Linkers to Improve Therapeutic Index of Radioligand Therapies. Molecules 2022; 27:molecules27154959. [PMID: 35956909 PMCID: PMC9370263 DOI: 10.3390/molecules27154959] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/28/2022] [Accepted: 08/01/2022] [Indexed: 01/11/2023] Open
Abstract
Radioligand therapy (RLT) is an emergent drug class for cancer treatment. The dose administered to cancer patients is constrained by the radiation exposure to normal tissues to maintain an appropriate therapeutic index. When a radiopharmaceutical or its radiometabolite is retained in the kidneys, radiation dose deposition in the kidneys can become a dose-limiting factor. A good exemplar is [177Lu]Lu-DOTATATE, where patients receive a co-infusion of basic amino acids for nephroprotection. Besides peptides, there are other classes of targeting vectors like antibody fragments, antibody mimetics, peptidomimetics, and small molecules that clear through the renal pathway. In this review, we will review established and emerging strategies that can be used to mitigate radiation-induced nephrotoxicity, with a focus on the development and incorporation of cleavable linkers for radiopharmaceutical designs. Finally, we offer our perspectives on cleavable linkers for RLT, highlighting future areas of research that will help advance the technology.
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Affiliation(s)
- Joseph Lau
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3, Canada
| | - Hwan Lee
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Julie Rousseau
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3, Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Correspondence: ; Tel.: +1-604-675-8208
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12
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Zhang M, Ye J, Xie Z, Wang Y, Ma W, Kang F, Yang W, Wang J, Chen X. Combined Probe Strategy to Increase the Enzymatic Digestion Rate and Accelerate the Renal Radioactivity Clearance of Peptide Radiotracers. Mol Pharm 2022; 19:1548-1556. [PMID: 35357154 DOI: 10.1021/acs.molpharmaceut.2c00051] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
High and sustained renal radioactivity accumulation is a major challenge in peptide-based radionuclide imaging and therapy. However, neutral endopeptidase (NEP)-based enzymatic hydrolysis to release and excrete the radioactive fragments has been proven to be an effective and promising way to reduce renal accumulation. Despite the improvement, the effect is still far from being satisfactory. To further reduce kidney uptake, we studied the relationship between the enzymatic reaction rate and the substrate concentration and came up with a combined probe strategy. Model compounds Boc-MVK-Dde and Boc-MFK-Dde were used for an in vitro enzymatic digestion study. NOTA-Exendin 4 and NOTA-MVK-Exendin 4 were labeled with 64Cu for in vivo dose-dependent micro-positron emission tomography (PET) studies. Groups 1 and 2 were injected with 0.2 and 0.8 nmol of 64Cu-NOTA-Exendin 4, respectively. Groups 3-6 were injected with 0.2, 0.8, 1.0, and 1.4 nmol of 64Cu-NOTA-MVK-Exendin 4, respectively. Groups 7 and 8 were co-injected with 0.2 nmol of 64Cu-NOTA-MVK-Exendin 4 and NOTA-MVK-PEG5K (1.3 and 2.6 nmol). The radioactivity uptakes were determined and compared within and among the groups. The in vitro cleavage study for both Boc-MVK-Dde and Boc-MFK-Dde indicated that within a certain concentration range, the enzyme digestion rate increased with increasing substrate concentration. The microPET images showed that the renal clearance could be accelerated significantly by increasing the injection dose of 64Cu-NOTA-MVK-Exendin 4, with the kidney uptakes being 60.98, 43.01, and 16.10 % ID/g at 1 h for groups 3, 4 and 5, respectively. Unfortunately, the tumor uptakes were also significantly inhibited as the injected dose of the tracer increased. However, with the co-injection of NOTA-MVK-PEG5K, the renal accumulation was significantly decreased without hampering the tumor uptake. As a result, the tumor-to-kidney ratios were significantly improved, which were 1.93, 3.47, 1.74, and 3.38 times that of group 3 at 1, 4, 24, and 48 h, respectively. The enzymatic reaction rate of NEP is dependent on the concentration of the substrates both in vitro and in vivo. The combined probe strategy developed in this study can dramatically reduce the renal accumulation of a peptide radioligand without affecting the tumor uptake, which shows great potential in peptide-based radiotheranostics.
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Affiliation(s)
- Mingru Zhang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Jiajun Ye
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Zhaojuan Xie
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Yirong Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Wenhui Ma
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Fei Kang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Weidong Yang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Jing Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Xiaoyuan Chen
- Departments of Diagnostic Radiology, Surgery, Chemical and Biomolecular Engineering, and Biomedical Engineering, Yong Loo Lin School of Medicine and Faculty of Engineering, National University of Singapore, Singapore 119074, Singapore.,Clinical Imaging Research Centre, Centre for Translational Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore.,Nanomedicine Translational Research Program, NUS Center for Nanomedicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
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13
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Zhang M, Ye J, Xie Z, Yan Y, Wang J, Chen X. Optimization of Enzymolysis Clearance Strategy To Enhance Renal Clearance of Radioligands. Bioconjug Chem 2021; 32:2108-2116. [PMID: 34486879 DOI: 10.1021/acs.bioconjchem.1c00392] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The kidney is the main dose-limiting organ in radioligand therapy (RLT), and there is an urgent need for reducing renal radioactivity accumulation. According to the enzymolysis clearance strategy, the first objective of this study is to test whether enzymolysis efficiency can be improved by introducing a hydrophobic amino acid with a bulkier side chain to the second position of the cleavable sequence, and the second objective is to screen an optimal sequence to minimize the renal uptake. Four exendin 4 (Ex4) peptide analogues with different cleavable sequences were synthesized and labeled with 68Ga. Both in vitro and in vivo metabolism studies were performed using either the model compounds or the complete probes. The in vitro stabilities of the tracers were evaluated in PBS and mouse serum. The microPET images were acquired in the INS-1 tumor model at different time points, and the radioactivity uptakes of the probes in tumors and kidneys were determined and compared. All the probes were stable in both PBS and mouse serum for at least 1 h. The in vitro cleavage study for both model compounds and intact probes showed enzymolysis efficiency in the following order: MWK > MFK > MVK > MGK. The in vivo metabolism study confirmed that a fragment of 68Ga-NOTA-Met-OH appeared in both kidney and urine samples for all analogues with MVK, MFK, and MWK sequences. The microPET images showed that the tumor uptakes of all the modified probes were comparable to those of the control, while the kidney uptakes were significantly reduced by inserting the MWK, MFK, or MVK linker. The tumor-to-kidney ratios at 0.5, 1, and 2 h time points showed the following order: 68Ga-NOTA-MWK-Ex4 > 68Ga-NOTA-MFK-Ex4 > 68Ga-NOTA-MVK-Ex4. In this study, based on the enzymolysis clearance strategy and the preference of the enzyme, different sequences were designed and compared both in vitro and in vivo. The results indicated that the larger the steric hindrance of the second hydrophobic amino acid side chain, the more effective the enzymatic hydrolysis, with enzymolysis efficiency in the following order: MWK > MFK > MVK > MGK. MWK appears to be the most effective sequence in reducing renal radioactivity accumulation of exendin 4 peptide derivatives.
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Affiliation(s)
- Mingru Zhang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi710032, China
- Departments of Diagnostic Radiology, Surgery, Chemical and Biomolecular Engineering, and Biomedical Engineering, Yong Loo Lin School of Medicine and Faculty of Engineering, National University of Singapore, Singapore, 119074, Singapore
| | - Jiajun Ye
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi710032, China
| | - Zhaojuan Xie
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi710032, China
| | - Yuhao Yan
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi710032, China
| | - Jing Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi710032, China
| | - Xiaoyuan Chen
- Departments of Diagnostic Radiology, Surgery, Chemical and Biomolecular Engineering, and Biomedical Engineering, Yong Loo Lin School of Medicine and Faculty of Engineering, National University of Singapore, Singapore, 119074, Singapore
- Clinical Imaging Research Centre, Centre for Translational Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore
- Nanomedicine Translational Research Program, NUS Center for Nanomedicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
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14
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Chigoho DM, Bridoux J, Hernot S. Reducing the renal retention of low- to moderate-molecular-weight radiopharmaceuticals. Curr Opin Chem Biol 2021; 63:219-228. [PMID: 34325089 DOI: 10.1016/j.cbpa.2021.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 02/06/2023]
Abstract
The field of nuclear imaging and therapy is rapidly progressing with the development of targeted radiopharmaceuticals that show rapid targeting and rapid clearance with minimal background. Unfortunately, they are often reabsorbed in the kidneys, leading to possible nephrotoxicity, limiting the therapeutic dose, and/or reducing imaging quality. The blocking of endocytic receptors has been extensively used as a strategy to reduce kidney radiation. Alternatively, the physicochemical properties of radiotracers can be modulated to either prevent their reuptake or promote the excretion of radiometabolites. Other interesting strategies focus on the insertion of a cleavable linker between the radiolabel and the targeting moiety or pretargeting approaches in which the targeting moiety and radiolabel are administered separately. In the context of this review, we will discuss the latest advances and insights on strategies used to reduce renal retention of low- to moderate-molecular-weight radiopharmaceuticals.
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Affiliation(s)
- Dora Mugoli Chigoho
- Laboratory for in Vivo Cellular and Molecular Imaging, ICMI-BEFY/MIMA, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Jessica Bridoux
- Laboratory for in Vivo Cellular and Molecular Imaging, ICMI-BEFY/MIMA, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Sophie Hernot
- Laboratory for in Vivo Cellular and Molecular Imaging, ICMI-BEFY/MIMA, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
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15
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Ahenkorah S, Cassells I, Deroose CM, Cardinaels T, Burgoyne AR, Bormans G, Ooms M, Cleeren F. Bismuth-213 for Targeted Radionuclide Therapy: From Atom to Bedside. Pharmaceutics 2021; 13:599. [PMID: 33919391 PMCID: PMC8143329 DOI: 10.3390/pharmaceutics13050599] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/14/2021] [Accepted: 04/17/2021] [Indexed: 12/17/2022] Open
Abstract
In contrast to external high energy photon or proton therapy, targeted radionuclide therapy (TRNT) is a systemic cancer treatment allowing targeted irradiation of a primary tumor and all its metastases, resulting in less collateral damage to normal tissues. The α-emitting radionuclide bismuth-213 (213Bi) has interesting properties and can be considered as a magic bullet for TRNT. The benefits and drawbacks of targeted alpha therapy with 213Bi are discussed in this review, covering the entire chain from radionuclide production to bedside. First, the radionuclide properties and production of 225Ac and its daughter 213Bi are discussed, followed by the fundamental chemical properties of bismuth. Next, an overview of available acyclic and macrocyclic bifunctional chelators for bismuth and general considerations for designing a 213Bi-radiopharmaceutical are provided. Finally, we provide an overview of preclinical and clinical studies involving 213Bi-radiopharmaceuticals, as well as the future perspectives of this promising cancer treatment option.
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Affiliation(s)
- Stephen Ahenkorah
- Institute for Nuclear Materials Science, Belgian Nuclear Research Center (SCK CEN), 2400 Mol, Belgium; (S.A.); (I.C.); (T.C.); (A.R.B.)
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, University of Leuven, 3000 Leuven, Belgium;
| | - Irwin Cassells
- Institute for Nuclear Materials Science, Belgian Nuclear Research Center (SCK CEN), 2400 Mol, Belgium; (S.A.); (I.C.); (T.C.); (A.R.B.)
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, University of Leuven, 3000 Leuven, Belgium;
| | - Christophe M. Deroose
- Nuclear Medicine Unit, University Hospitals Leuven, 3000 Leuven, Belgium;
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University of Leuven, 3000 Leuven, Belgium
| | - Thomas Cardinaels
- Institute for Nuclear Materials Science, Belgian Nuclear Research Center (SCK CEN), 2400 Mol, Belgium; (S.A.); (I.C.); (T.C.); (A.R.B.)
- Department of Chemistry, University of Leuven, 3001 Leuven, Belgium
| | - Andrew R. Burgoyne
- Institute for Nuclear Materials Science, Belgian Nuclear Research Center (SCK CEN), 2400 Mol, Belgium; (S.A.); (I.C.); (T.C.); (A.R.B.)
| | - Guy Bormans
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, University of Leuven, 3000 Leuven, Belgium;
| | - Maarten Ooms
- Institute for Nuclear Materials Science, Belgian Nuclear Research Center (SCK CEN), 2400 Mol, Belgium; (S.A.); (I.C.); (T.C.); (A.R.B.)
| | - Frederik Cleeren
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, University of Leuven, 3000 Leuven, Belgium;
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16
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Preparation and Biological Evaluation of [ 99mTc]Tc-CNGU as a PSMA-Targeted Radiotracer for the Imaging of Prostate Cancer. Molecules 2020; 25:molecules25235548. [PMID: 33256058 PMCID: PMC7730407 DOI: 10.3390/molecules25235548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/21/2020] [Accepted: 11/23/2020] [Indexed: 12/24/2022] Open
Abstract
Prostate-specific membrane antigen (PSMA) is a well-established biological target that is overexpressed on the surface of prostate cancer lesions. Radionuclide-labeled small-molecule PSMA inhibitors have been shown to be promising PSMA-specific agents for the diagnosis and therapy of prostate cancer. In this study, a glutamate-urea-based PSMA-targeted ligand containing an isonitrile (CNGU) was synthesized and labeled with 99mTc to prepare [99mTc]Tc-CNGU with a high radiochemical purity (RCP). The CNGU ligand showed a high affinity toward PSMA (Ki value is 8.79 nM) in LNCaP cells. The [99mTc]Tc-CNGU exhibited a good stability in vitro and hydrophilicity (log P = −1.97 ± 0.03). In biodistribution studies, BALB/c nude mice bearing LNCaP xenografts showed that the complex had a high tumor uptake with 4.86 ± 1.19% ID/g, which decreased to 1.74 ± 0.90% ID/g after a pre-injection of the selective PSMA inhibitor ZJ-43, suggesting that it was a PSMA-specific agent. Micro-SPECT imaging demonstrated that the [99mTc]Tc-CNGU had a tumor uptake and that the uptake was reduced in the image after blocking with ZJ-43, further confirming its PSMA specificity. All of the results in this work indicated that [99mTc]Tc-CNGU is a promising PSMA-specific tracer for the imaging of prostate cancer.
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