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Ramogida C, Price E. Transition and Post-Transition Radiometals for PET Imaging and Radiotherapy. Methods Mol Biol 2024; 2729:65-101. [PMID: 38006492 DOI: 10.1007/978-1-0716-3499-8_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
Radiometals are an exciting class of radionuclides because of the large number of metallic elements available that have medically useful isotopes. To properly harness radiometals, they must be securely bound by chelators, which must be carefully matched to the radiometal ion to maximize radiolabeling performance and the stability of the resulting complex. This chapter focuses on practical aspects of radiometallation chemistry including chelator selection, radiolabeling procedures and conditions, radiolysis prevention, purification, quality control, requisite equipment and reagents, and useful tips.
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Affiliation(s)
- Caterina Ramogida
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada.
- Life Sciences Division, TRIUMF, Vancouver, BC, Canada.
| | - Eric Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK, Canada
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Larenkov A, Mitrofanov I, Pavlenko E, Rakhimov M. Radiolysis-Associated Decrease in Radiochemical Purity of 177Lu-Radiopharmaceuticals and Comparison of the Effectiveness of Selected Quenchers against This Process. Molecules 2023; 28:molecules28041884. [PMID: 36838872 PMCID: PMC9967390 DOI: 10.3390/molecules28041884] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
The radiolytic degradation of vector molecules is a major factor affecting the shelf life of therapeutic radiopharmaceuticals. The development of time-stable dosage forms of radiopharmaceuticals is the key to their successful implementation in clinical practice. Using [177Lu]Lu-PSMA-617 molecule as an example, the time dependence of the change in radiochemical purity (RCP, %) under radiolysis conditions was studied. The dependence of [177Lu]Lu-PSMA-617 radiolysis on parameters such as time, radionuclide activity, buffer agent concentration, precursor amount, and preparation volume was evaluated. It was shown that the absorbed dose was the dominant factor influencing the RCP. The RCP value is inversely proportional to the absorbed dose in the [177Lu]Lu-PSMA-617 preparation and has an exponential dependence. The lutetium-177 dose factor ψ (Gy·mL·MBq-1) and PSMA-617 concentration-dependent dose constant κ (Gy-1) were evaluated for absorbed dose estimation via computer modeling, chemical dosimetry, and radiochemical purity monitoring under various conditions. The further refinement and application of the dependencies found can be useful for predicting the RCP value at the stage of optimizing the composition of the finished dosage form of therapeutic radiopharmaceuticals. The influence of the buffer agent (sodium acetate) concentration on [177Lu]Lu-PSMA-617 radiolytic degradation was shown and should be considered both when developing a dosage form, and when comparing the results of independent studies. The effectiveness of the addition of various stabilizing agents, such as DMSA, cysteine, gentisic acid, vanillin, methionine, adenine, dobesilic acid, thymine, uracil, nicotinamide, meglumine, and mannitol, in suppressing the effects of radiolysis was evaluated.
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Baudhuin H, Cousaert J, Vanwolleghem P, Raes G, Caveliers V, Keyaerts M, Lahoutte T, Xavier C. 68Ga-Labeling: Laying the Foundation for an Anti-Radiolytic Formulation for NOTA-sdAb PET Tracers. Pharmaceuticals (Basel) 2021; 14:ph14050448. [PMID: 34068666 PMCID: PMC8151064 DOI: 10.3390/ph14050448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/04/2021] [Accepted: 05/07/2021] [Indexed: 01/15/2023] Open
Abstract
During the preparation of [68Ga]Ga-NOTA-sdAb at high activity, degradation of the tracers was observed, impacting the radiochemical purity (RCP). Increasing starting activities in radiolabelings is often paired with increased degradation of the tracer due to the formation of free radical species, a process known as radiolysis. Radical scavengers and antioxidants can act as radioprotectant due to their fast interaction with formed radicals and can therefore reduce the degree of radiolysis. This study aims to optimize a formulation to prevent radiolysis during the labeling of NOTA derivatized single domain antibody (sdAbs) with 68Ga. Gentisic acid, ascorbic acid, ethanol and polyvinylpyrrolidone were tested individually or in combination to find an optimal mix able to prevent radiolysis without adversely influencing the radiochemical purity (RCP) or the functionality of the tracer. RCP and degree of radiolysis were assessed via thin layer chromatography and size exclusion chromatography for up to three hours after radiolabeling. Individually, the radioprotectants showed insufficient efficacy in reducing radiolysis when using high activities of 68Ga, while being limited in amount due to negative impact on radiolabeling of the tracer. A combination of 20% ethanol (VEtOH/VBuffer%) and 5 mg ascorbic acid proved successful in preventing radiolysis during labeling with starting activities up to 1-1.2 GBq of 68Ga, and is able to keep the tracer stable for up to at least 3 h after labeling at room temperature. The prevention of radiolysis by the combination of ethanol and ascorbic acid potentially allows radiolabeling compatibility of NOTA-sdAbs with all currently available 68Ge/68Ga generators. Additionally, a design is proposed to allow the incorporation of the radioprotectant in an ongoing diagnostic kit development for 68Ga labeling of NOTA-sdAbs.
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Affiliation(s)
- Henri Baudhuin
- Department of Medical Imaging (MIMA), Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium; (P.V.); (V.C.); (M.K.); (T.L.); (C.X.)
- Correspondence: ; Tel.: +32-2-477-4991
| | - Julie Cousaert
- Nuclear Medicine Department (NUCG), Universitair Ziekenhuis Brussel (UZ Brussel), Laarbeeklaan 101, B-1090 Brussels, Belgium;
| | - Philippe Vanwolleghem
- Department of Medical Imaging (MIMA), Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium; (P.V.); (V.C.); (M.K.); (T.L.); (C.X.)
| | - Geert Raes
- Unit of Cellular and Molecular Immunology (CMIM), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium;
- Myeloid Cell Immunology Laboratory (MCI), VIB Center for Inflammation Research, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Vicky Caveliers
- Department of Medical Imaging (MIMA), Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium; (P.V.); (V.C.); (M.K.); (T.L.); (C.X.)
- Nuclear Medicine Department (NUCG), Universitair Ziekenhuis Brussel (UZ Brussel), Laarbeeklaan 101, B-1090 Brussels, Belgium;
| | - Marleen Keyaerts
- Department of Medical Imaging (MIMA), Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium; (P.V.); (V.C.); (M.K.); (T.L.); (C.X.)
- Nuclear Medicine Department (NUCG), Universitair Ziekenhuis Brussel (UZ Brussel), Laarbeeklaan 101, B-1090 Brussels, Belgium;
| | - Tony Lahoutte
- Department of Medical Imaging (MIMA), Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium; (P.V.); (V.C.); (M.K.); (T.L.); (C.X.)
- Nuclear Medicine Department (NUCG), Universitair Ziekenhuis Brussel (UZ Brussel), Laarbeeklaan 101, B-1090 Brussels, Belgium;
| | - Catarina Xavier
- Department of Medical Imaging (MIMA), Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium; (P.V.); (V.C.); (M.K.); (T.L.); (C.X.)
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Bandari RP, Carmack TL, Malhotra A, Watkinson L, Fergason Cantrell EA, Lewis MR, Smith CJ. Development of Heterobivalent Theranostic Probes Having High Affinity/Selectivity for the GRPR/PSMA. J Med Chem 2021; 64:2151-2166. [PMID: 33534560 DOI: 10.1021/acs.jmedchem.0c01785] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In this study, we describe the development of heterobivalent [DUPA-6-Ahx-([111In]In-DO3A)-8-Aoc-BBN ANT] and [DUPA-6-Ahx-([177Lu]Lu-DO3A)-8-Aoc-BBN ANT] radiotracers that display very high selectivity/specificity for gastrin-releasing peptide receptor (GRPR)-/prostate-specific membrane antigen (PSMA)-expressing cells. These studies include metallation, purification, characterization, and in vitro and in vivo evaluation of the new small-molecule-/peptide-based radiopharmaceuticals having utility for imaging and potentially therapy. Competitive displacement binding assays using PC-3 cells and LNCaP cell membranes showed high binding affinity for the GRPR or the PSMA. Biodistribution studies showed favorable excretion pharmacokinetics with high tumor uptake in PC-3 or PC-3 prostatic inhibin peptide (PIP) tumor-bearing mice. For example, tumor accumulation at the 1 h time point ranged from (4.74 ± 0.90) to (7.51 ± 2.61)%ID/g. Micro-single-photon emission computed tomography (microSPECT) molecular imaging investigations showed very high uptake in tumors with minimal accumulation of tracers in the surrounding collateral tissues in xenografted mice at 4 h postintravenous injection. In conclusion, [DUPA-6-Ahx-([111In]In-DO3A)-8-Aoc-BBN ANT] and [DUPA-6-Ahx-([177Lu]Lu-DO3A)-8-Aoc-BBN ANT] tracers displayed favorable pharmacokinetic and excretion profiles with high uptake and retention in tumors.
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Affiliation(s)
- Rajendra P Bandari
- Research Division, Harry S. Truman Memorial Veterans' Hospital, Research Service Room A005, 800 Hospital Drive, Columbia, Missouri 65201, United States.,Department of Radiology, University of Missouri School of Medicine, Columbia, Missouri 65211, United States
| | - Terry L Carmack
- Research Division, Harry S. Truman Memorial Veterans' Hospital, Research Service Room A005, 800 Hospital Drive, Columbia, Missouri 65201, United States.,University of Missouri Research Reactor Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Anil Malhotra
- Research Division, Harry S. Truman Memorial Veterans' Hospital, Research Service Room A005, 800 Hospital Drive, Columbia, Missouri 65201, United States
| | - Lisa Watkinson
- Research Division, Harry S. Truman Memorial Veterans' Hospital, Research Service Room A005, 800 Hospital Drive, Columbia, Missouri 65201, United States.,University of Missouri Research Reactor Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Emily A Fergason Cantrell
- Research Division, Harry S. Truman Memorial Veterans' Hospital, Research Service Room A005, 800 Hospital Drive, Columbia, Missouri 65201, United States.,University of Missouri Research Reactor Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Michael R Lewis
- Department of Veterinary Medicine and Surgery, University of Missouri College of Veterinary Medicine, Columbia, Missouri 65211, United States
| | - Charles J Smith
- Research Division, Harry S. Truman Memorial Veterans' Hospital, Research Service Room A005, 800 Hospital Drive, Columbia, Missouri 65201, United States.,Department of Radiology, University of Missouri School of Medicine, Columbia, Missouri 65211, United States.,University of Missouri Research Reactor Center, University of Missouri, Columbia, Missouri 65211, United States
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Fully automated preparation of 68Ga-PSMA-11 at curie level quantity using cyclotron-produced 68Ga for clinical applications. Appl Radiat Isot 2020; 155:108936. [PMID: 31655351 DOI: 10.1016/j.apradiso.2019.108936] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/03/2019] [Accepted: 10/10/2019] [Indexed: 02/07/2023]
Abstract
68Ga-PSMA-11 is currently one of the most investigated PET agents for imaging both recurrent prostate cancer and relevant metastases; however, the production and distribution of 68Ga-PSMA-11 is limited to a supply of only a few daily doses when using a commercially available 68Ge/68Ga generator. 68Ge/68Ga generators deliver only a modest amount of activity, up to 1850 MBq (50 mCi), when new, but it decreases with time. Additionally, the production of 68Ga/68Ge generators has not been able to meet the increasing demand of 68Ga radiotracers. In response to the need for a more economically viable alternative, the focus of this study was to provide a simple and efficient method for producing 68Ga-PSMA-11, using cyclotron-produced 68Ga that is ready for routine clinical practice.
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6
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Trindade V, Balter H. Oxidant and Antioxidant Effects of Gentisic Acid in a <sup>177</sup>Lu-Labelled Methionine-Containing Minigastrin Analogue. Curr Radiopharm 2019; 13:107-119. [PMID: 31526356 PMCID: PMC7527569 DOI: 10.2174/1874471012666190916112904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/14/2019] [Accepted: 08/27/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND The radiolabelling of receptor-binding peptides for therapy is a challenge since the peptide itself is exposed (during labelling, storage and transport) to radiation-induced damage, directly or indirectly, in aqueous solution. Hence, the use of radiostabilizers seems to be mandatory, especially in peptide molecules that contain radiation-sensitive amino acids. OBJECTIVE The aim of this study was to investigate the effect of two stabilizers, gentisic acid and methionine, to delve into how each of them affects the radiolabelling and stability of the minigastrin analogue [177Lu]Lu-DOTA-His-His-Glu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 through the analysis of the 22 species distinguished over time by an optimized HPLC system. METHODS The stabilizers, in different combinations, were present from the beginning of the labelling process carried out at 96 °C for 15 min. The stability was studied for up to 7 days. RESULTS The unexpected selective oxidation of the methionine residue of the radiolabelled peptide, promoted by gentisic acid, led to studying the effect of pH, from 3.5 to 6.0, in the presence of only this stabilizer. A pH-dependent antioxidant behaviour was revealed, showing a decrease in peptide impurities but an increase in the selective oxidation as the pH was increased. CONCLUSION The selective oxidation of the methionine residue could be induced by oxidizing species probably produced in the reaction between gentisic acid and free radicals of water, during the protection of the radiolabelled peptide from the attack of these harmful species. Therefore, the addition of methionine becomes necessary to effectively decrease this selective oxidation in the methioninecontaining peptide.
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Affiliation(s)
- Victoria Trindade
- Radiopharmacy Department, Uruguayan Centre of Molecular Imaging (CUDIM), Montevideo, Uruguay
| | - Henia Balter
- Radiopharmacy Department, Uruguayan Centre of Molecular Imaging (CUDIM), Montevideo, Uruguay
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7
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Stability Evaluation and Stabilization of a Gastrin-Releasing Peptide Receptor (GRPR) Targeting Imaging Pharmaceutical. Molecules 2019; 24:molecules24162878. [PMID: 31398865 PMCID: PMC6720803 DOI: 10.3390/molecules24162878] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/24/2019] [Accepted: 08/06/2019] [Indexed: 01/15/2023] Open
Abstract
The prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptor (GRPR) are identified as important targets on prostate cancer. Receptor-targeting radiolabeled imaging pharmaceuticals with high affinity and specificity are useful in studying and monitoring biological processes and responses. Two potential imaging pharmaceuticals, AMBA agonist (where AMBA = DO3A-CH2CO-G-[4-aminobenzyl]- Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2) and RM1 antagonist (where RM1 = DO3A-CH2CO-G-[4-aminobenzyl]-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2), have demonstrated high binding affinity (IC50) to GRP receptors and high tumor uptake. Antagonists, despite the poor tumor cell internalization properties, can show clearer images and pharmacokinetic profiles by virtue of their higher tumor uptake in animal models compared to agonists. For characterization, development, and translation of a potential imaging pharmaceutical into the clinic, it must be evaluated in a series of tests, including in vitro cell binding assays, in vitro buffer and serum stability studies, the biodistribution of the radiolabeled material, and finally imaging studies in preclinical animal models. Data related to acetate buffer, mouse, canine, and human sera stability of 177Lu-labeled RM1 are presented here and compared with the acetate buffer and sera stability data of AMBA agonist. The samples of 177Lu-labeled RM1 with a high radioconcentration degrade faster than low-radioconcentration samples upon storage at 2–8 °C. Addition of stabilizers, ascorbic acid and gentisic acid, improve the stability of 177Lu-labeled RM1 significantly with gentisic acid being more efficient than ascorbic acid as a stabilizer. The degradation kinetics of 177Lu-labeled AMBA and RM1 in sera follow the order (fastest to slowest): mouse > canine > human sera. Finally, 177Lu-labeled RM1 antagonist is slower to degrade in mouse, canine, and human sera than 177Lu-labeled AMBA agonist, further suggesting that an antagonist is a more promising candidate than agonist for the positron emission tomography (PET) imaging and therapy of prostate cancer patients.
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Comparative Study of Subcutaneous and Orthotopic Mouse Models of Prostate Cancer: Vascular Perfusion, Vasculature Density, Hypoxic Burden and BB2r-Targeting Efficacy. Sci Rep 2019; 9:11117. [PMID: 31366895 PMCID: PMC6668441 DOI: 10.1038/s41598-019-47308-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/08/2019] [Indexed: 12/22/2022] Open
Abstract
The gastrin-releasing peptide receptor (BB2r) is overexpressed in a variety of cancers including prostate cancer. As a consequence, the development of BB2r-targeted diagnostic/therapeutic radiopharmaceuticals has been widely explored. Both subcutaneous and orthotopic mouse models have been extensively used in BB2r-targeted agent development, but side-by-side studies examining how biological parameters (tumor perfusion efficacy, hypoxic burden and microvasculature density) impact BB2r-targeted agent delivery has not been reported. Herein, we examine these biological parameters using subcutaneous and orthotopic PC-3 xenografts. Using a dual isotope biodistribution study, tumor perfusion was accessed using [99mTc]NaTcO4 and BB2r-targeted uptake evaluated by utilization of a novel 177Lu-labeled conjugate ([177Lu]Lu-DOTA-SP714). Immunofluorescence, immunohistochemistry and autoradiography were utilized to examine the tumor vascular density, hypoxic burden and microdistribution of the BB2r-targeted agent. Our studies demonstrated that compared to the subcutaneous model the PC-3 orthotopic tumors had significantly higher levels of perfusion that led to higher BB2r-targeted uptake and lower levels of hypoxia burden. It is anticipated that our results will allow researchers to better understand the biological variables affecting drug delivery and assist them in more clearly interpreting their results in this common prostate cancer mouse model.
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Maintaining radiochemical purity of [177Lu]Lu-DOTA-PSMA-617 for PRRT by reducing radiolysis. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06573-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Cheng S, Lang L, Wang Z, Jacobson O, Yung B, Zhu G, Gu D, Ma Y, Zhu X, Niu G, Chen X. Positron Emission Tomography Imaging of Prostate Cancer with Ga-68-Labeled Gastrin-Releasing Peptide Receptor Agonist BBN 7-14 and Antagonist RM26. Bioconjug Chem 2018; 29:410-419. [PMID: 29254329 PMCID: PMC5824342 DOI: 10.1021/acs.bioconjchem.7b00726] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Radiolabeled
bombesin (BBN) analogs have long been used for developing
gastrin-releasing peptide receptor (GRPR) targeted imaging probes,
and tracers with excellent in vivo performance including high tumor
uptake, high contrast, and favorable pharmacokinetics are highly desired.
In this study, we compared the 68Ga-labeled GRPR agonist
(Gln–Trp–Ala–Val–Gly–His–Leu–Met–NH2, BBN7–14) and antagonist (d-Phe–Gln–Trp–Ala–Val–Gly–His–Sta–Leu–NH2, RM26) for the positron emission tomography (PET) imaging
of prostate cancer. The in vitro stabilities, receptor binding, cell
uptake, internalization, and efflux properties of the probes 68Ga–1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA)–Aca–BBN7–14 and 68Ga–NOTA–poly(ethylene
glycol)3 (PEG3)–RM26 were studied in
PC-3 cells, and the in vivo GRPR targeting abilities and kinetics
were investigated using PC-3 tumor xenografted mice. BBN7–14, PEG3-RM26, NOTA–Aca–BBN7–14, and NOTA–PEG3–RM26 showed similar binding
affinity to GRPR. In PC-3 tumor-bearing mice, the tumor uptake of 68Ga–NOTA–PEG3–RM26 remained
at around 3.00 percentage of injected dose per gram of tissue within
1 h after injection, in contrast with 68Ga–NOTA–Aca–BBN7–14, which demonstrated rapid elimination and high
background signal. Additionally, the majority of the 68Ga–NOTA–PEG3–RM26 remained intact
in mouse serum at 5 min after injection, while almost all of the 68Ga–NOTA–Aca–BBN7–14 was degraded under the same conditions, demonstrating more-favorable
in vivo pharmacokinetic properties and metabolic stabilities of the
antagonist probe relative to its agonist counterpart. Overall, the
antagonistic GRPR targeted probe 68Ga–NOTA–PEG3–RM26 is a more-promising candidate than the agonist 68Ga–NOTA–Aca–BBN7–14 for the PET imaging of prostate cancer patients.
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Affiliation(s)
- Siyuan Cheng
- Department of Nuclear Medicine and PET, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430000, PR China.,Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Lixin Lang
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Zhantong Wang
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Orit Jacobson
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Bryant Yung
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Guizhi Zhu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Dongyu Gu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Ying Ma
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Xiaohua Zhu
- Department of Nuclear Medicine and PET, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430000, PR China
| | - Gang Niu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH) , Bethesda, Maryland 20892, United States
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Tian FY, Yang F, Jiang XQ, Wu Q, Wang J. Syntheses, structural determination, and binding studies of binuclear nine-coordinate (MnH)4[Ho
2
III
(Dtpa)2] · 12H2O and polynuclear nine-coordinate {(MnH)[HoIII(Egta)] · 3H2O}
n. RUSS J COORD CHEM+ 2017. [DOI: 10.1134/s1070328417070089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Monooxorhenium(V) complexes with 222-N 2S 2 MAMA ligands for bifunctional chelator agents: Syntheses and preliminary in vivo evaluation. Nucl Med Biol 2016; 43:802-811. [PMID: 27694058 PMCID: PMC5118109 DOI: 10.1016/j.nucmedbio.2016.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 08/24/2016] [Accepted: 08/29/2016] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Targeted radiotherapy using the bifunctional chelate approach with 186/188Re(V) is challenging because of the susceptibility of monooxorhenium(V)-based complexes to oxidize in vivo at high dilution. A monoamine-monoamide dithiol (MAMA)-based bifunctional chelating agent was evaluated with both rhenium and technetium to determine its utility for in vivo applications. METHODS A 222-MAMA chelator, 222-MAMA(N-6-Ahx-OEt) bifunctional chelator, and 222-MAMA(N-6-Ahx-BBN(7-14)NH2) were synthesized, complexed with rhenium, radiolabeled with 99mTc and 186Re (carrier added and no carrier added), and evaluated in initial biological distribution studies. RESULTS An IC50 value of 2.0±0.7nM for natReO-222-MAMA(N-6-Ahx-BBN(7-14)NH2) compared to [125I]-Tyr4-BBN(NH2) was determined through competitive cell binding assays with PC-3 tumor cells. In vivo evaluation of the no-carrier added 99mTc-222-N2S2(N-6-Ahx-BBN(7-14)NH2) complex showed little gastric uptake and blockable pancreatic uptake in normal mice. CONCLUSIONS The 186ReO-222-N2S2(N-6-Ahx-BBN(7-14)NH2) complex showed stability in biological media, which indicates that the 222-N2S2 chelator is appropriate for chelating 186/188Re in radiopharmaceuticals involving peptides. Additionally, the in vitro cell studies showed that the ReO-222-N2S2(N-6-Ahx-BBN(7-14)NH2) complex (macroscopically) bound to PC3-tumor cell surface receptors with high affinity. The 99mTc analog was stable in vivo and exhibited pancreatic uptake in mice that was blockable, indicating BB2r targeting.
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Valverde IE, Vomstein S, Mindt TL. Toward the Optimization of Bombesin-Based Radiotracers for Tumor Targeting. J Med Chem 2016; 59:3867-77. [PMID: 27054526 DOI: 10.1021/acs.jmedchem.6b00025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The peptide bombesin (BBN) is a peptide with high affinity for the gastrin-releasing peptide receptor (GRPr), a receptor that is overexpressed by, for example, breast and prostate cancers. Thus, GRPr agonists can be used as cancer-targeting vectors to shuttle diagnostic and therapeutic agents into tumor cells. With the aim of optimizing the tumor targeting properties of a radiolabeled [Nle(14)]BBN(7-14) moiety, novel BBN(7-14)- and BBN(6-14)-based radioconjugates were synthesized, labeled with Lu-177, and fully evaluated in vitro and in vivo. The effect of residue and backbone modification on several parameters such as the internalization of the radiolabeled peptides into PC3 and AR42J tumor cells, their affinity toward the human GRPr, metabolic stability in blood plasma, and biodistribution in mice bearing GRPr-expressing PC3 xenografts was studied. As a result of our investigations, a novel radiolabeled GRPr agonist with a high tumor uptake and a high tumor-to-kidney ratio was identified.
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Affiliation(s)
- Ibai E Valverde
- Division of Radiopharmaceutical Chemistry, University of Basel Hospital , Petersgraben 4, 4031 Basel, Switzerland
| | - Sandra Vomstein
- Division of Radiopharmaceutical Chemistry, University of Basel Hospital , Petersgraben 4, 4031 Basel, Switzerland
| | - Thomas L Mindt
- Division of Radiopharmaceutical Chemistry, University of Basel Hospital , Petersgraben 4, 4031 Basel, Switzerland.,Ludwig Boltzmann Institute for Applied Diagnostics, General Hospital of Vienna , Währinger Gürtel 18-20, A-1090 Vienna, Austria
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15
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Pandey U, Mukherjee A, Jindal A, Gamre N, Korde A, Ram R, Sarma HD, Dash A. Preparation and evaluation of a single vial AMBA kit for 68Ga labeling with potential for imaging of GRP receptor-positive cancers. J Radioanal Nucl Chem 2015. [DOI: 10.1007/s10967-015-4290-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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16
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Shrivastava A, Ding H, Kothandaraman S, Wang SH, Gong L, Williams M, Milum K, Zhang S, Tweedle MF. A high-affinity near-infrared fluorescent probe to target bombesin receptors. Mol Imaging Biol 2015; 16:661-9. [PMID: 24604209 DOI: 10.1007/s11307-014-0727-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE This study aimed to create new optical surgical navigation NIRF probes for prostate and breast cancers. PROCEDURES IR800-linker-QWAVGHLM-NH2 with linker = GSG, GGG, and G-Abz4 were synthesized and characterized. IC50 for bombesin receptors (BBN-R) in PC-3 prostate and T47D breast cancer cells, fluorescence microscopy in PC-3 cells, and NIRF imaging in mice PC-3 tumor xenografts were studied. RESULTS GGG, GSG, and G-Abz4 derivatives had IC50 (nM) for BBN-R+ PC-3 cells = 187 ± 31, 56 ± 5, and 2.6 ± 0.2 and T47D cells = 383 ± 1, 57.4 ± 1.2, and 3.1 ± 1.1, respectively. By microscopy the Abz4 derivative showed the highest uptake, was competed with by BBN, and had little to no binding to BBN-R- cells. In NIRF imaging the G-Abz4 probe was brighter than GGG probe in BBN-R+ tissues in vivo and tissues, tumors, and tumor slices ex vivo. Uptake could be partially blocked in BBN-R+ pancreas but not visibly in tumor. CONCLUSIONS Linker choice can dominate peptidic BBN-R binding. The G-Abz4 linker yields a higher affinity and specific BBN-R binder in this series of molecules.
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Affiliation(s)
- Ajay Shrivastava
- Department of Radiology, The Ohio State University, Columbus, OH, 43210, USA
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17
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Banerjee S, Pillai MRA, Knapp FFR. Lutetium-177 therapeutic radiopharmaceuticals: linking chemistry, radiochemistry, and practical applications. Chem Rev 2015; 115:2934-74. [PMID: 25865818 DOI: 10.1021/cr500171e] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Sharmila Banerjee
- Radiopharmaceuticals Chemistry Section, Bhabha Atomic Research Centre (BARC), Mumbai 400 085, India.,Molecular Group of Companies, Puthuvype, Ernakulam, Kerala 682 508, India.,Medical Radioisotope Program, Oak Ridge National Laboratory (ORNL), P.O. Box 2008, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830-6229, United States
| | - M R A Pillai
- Radiopharmaceuticals Chemistry Section, Bhabha Atomic Research Centre (BARC), Mumbai 400 085, India.,Molecular Group of Companies, Puthuvype, Ernakulam, Kerala 682 508, India.,Medical Radioisotope Program, Oak Ridge National Laboratory (ORNL), P.O. Box 2008, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830-6229, United States
| | - F F Russ Knapp
- Radiopharmaceuticals Chemistry Section, Bhabha Atomic Research Centre (BARC), Mumbai 400 085, India.,Molecular Group of Companies, Puthuvype, Ernakulam, Kerala 682 508, India.,Medical Radioisotope Program, Oak Ridge National Laboratory (ORNL), P.O. Box 2008, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830-6229, United States
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18
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de Blois E, Chan HS, de Zanger R, Konijnenberg M, Breeman WAP. Application of single-vial ready-for-use formulation of 111In- or 177Lu-labelled somatostatin analogs. Appl Radiat Isot 2013; 85:28-33. [PMID: 24365877 DOI: 10.1016/j.apradiso.2013.10.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/04/2013] [Accepted: 10/26/2013] [Indexed: 02/04/2023]
Abstract
For the sake of safety it would be desirable to store and transport the ready-for-use liquid formulation (diagnostics and therapeutics) of radiolabelled peptides. The use of ethanol, in combination with a mixture of gentisic- and ascorbic acid, has superior effects on stabilizing radiolabelled somatostatin analogs. As a consequence, (111)In- and (177)Lu-labelled somatostatin analogs can be stored and transported in a single-vial ready-for-use liquid formulation up to 7 days after radiolabelling.
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Affiliation(s)
- Erik de Blois
- Erasmus MC Rotterdam, Department of Nuclear Medicine, 's Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | - Ho Sze Chan
- Erasmus MC Rotterdam, Department of Nuclear Medicine, 's Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | - Rory de Zanger
- Erasmus MC Rotterdam, Department of Nuclear Medicine, 's Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | - Mark Konijnenberg
- Erasmus MC Rotterdam, Department of Nuclear Medicine, 's Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
| | - Wouter A P Breeman
- Erasmus MC Rotterdam, Department of Nuclear Medicine, 's Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
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19
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Asti M, Iori M, Capponi PC, Atti G, Rubagotti S, Martin R, Brennauer A, Müller M, Bergmann R, Erba PA, Versari A. Influence of different chelators on the radiochemical properties of a 68-Gallium labelled bombesin analogue. Nucl Med Biol 2013; 41:24-35. [PMID: 24183610 DOI: 10.1016/j.nucmedbio.2013.08.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/27/2013] [Accepted: 08/27/2013] [Indexed: 01/05/2023]
Abstract
UNLABELLED The radiolabelled bombesin analogue AMBA shows high potential for diagnosis and treatment of prostate and breast cancer, but the influence of different chelators, which differ in terms of radiochemical reactivity and stability, have not been explored so far. In order to find the best suitable chelator for labelling of AMBA, we synthesized AMBA analogues linked to the most commonly used chelators DOTA, NOTA and NODAGA and compared their reactivity and stability after labelling with 68-Gallium. METHODS For the synthesis of DO3A-, NO2A- and NODAGA-AMBA, a solid-phase synthesis approach was used. The influence of concentration, pH and temperature on the radiolabelling was analysed. The in vitro stability of all complexes in saline, human serum, human whole blood and against transchelation and transmetallation was analysed. RESULTS The peptides were synthesised in high yield and purity. Purity and identity of products and impurities were confirmed using UHPLC coupled to ESI-MS. Radiolabelling of these peptides was optimal at elevated temperature, although room temperature labelling was reported previously for NOTA and NODAGA chelators. The highest reactivity was observed for NODAGA-AMBA. On preparation of NO2A-AMBA, the formation of a by-product was detected with HPLC. More detailed analysis revealed the formation of an isomer with the same mass to charge ratio which led to the conclusion that a coordination isomer was formed. All complexes showed high stability in saline, human serum or when challenged with DTPA, transferrin and varying metals (Fe(3+), Cu(2+), Zn(2+)). Conversely, the stability in human blood was low, and varying metabolites were detected and identified by ESI-MS. CONCLUSION All three precursors are available in high yields suitable for routine production. NODAGA-AMBA showed the most favoured features when labelled with 68-gallium, but a further comparison in vivo should be performed in order to confirm the superior features found in vitro.
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Affiliation(s)
- Mattia Asti
- Nuclear Medicine Unit, Oncology and Advanced Technologies Department, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
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20
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Bai Y, Gao JQ, Wang J, Jin XD, Li Y, Wang B, Wu T, Zhang XD. Syntheses, structural determination, and binding studies of mononuclear nine-coordinate (EnH2)1.5[HoIII(Ttha)] · 4.5H2O and two dimensional unlimited network (EnH2)[HoIII(Egta)(H2O)]2 · 6H2O. RUSS J COORD CHEM+ 2012. [DOI: 10.1134/s1070328413010028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Pujatti PB, Massicano AVF, Mengatti J, de Araújo EB. Preparation of [In-111]-labeled-DTPA-bombesin conjugates at high specific activity and stability: evaluation of labeling parameters and potential stabilizers. Appl Radiat Isot 2012; 70:856-63. [PMID: 22405643 DOI: 10.1016/j.apradiso.2012.02.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Revised: 01/26/2012] [Accepted: 02/19/2012] [Indexed: 01/16/2023]
Abstract
The aim of the present work was to obtain stabilized high specific activity (HSA) (111)In-labeled bombesin conjugates for preclinical evaluations. Parameters influencing the kinetics of labeling were investigated and the effect of stabilizers on HSA radiopeptides stability at room temperature were systematically categorized applying chromatography techniques. A SA of 174 GBq/μmol was achieved with high radiochemical purity, but the labeled compounds exhibited low stability. The addition of stabilizers avoided their radiolysis and significantly increased their stability.
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Affiliation(s)
- P B Pujatti
- Directory of Radiopharmacy, Nuclear and Energy Research Institute, Cidade Universitária da USP - Butantã, São Paulo, Brazil.
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22
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Ballard B, Jiang Z, Soll CE, Revskaya E, Cutler CS, Dadachova E, Francesconi LC. In vitro and in vivo evaluation of melanin-binding decapeptide 4B4 radiolabeled with 177Lu, 166Ho, and 153Sm radiolanthanides for the purpose of targeted radionuclide therapy of melanoma. Cancer Biother Radiopharm 2011; 26:547-56. [PMID: 21970319 DOI: 10.1089/cbr.2011.0954] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Melanoma is a malignancy with increasing incidence. Although primary tumors that are localized to the skin can be successfully treated by surgical removal, there is no satisfactory treatment for metastatic melanoma, a condition that has currently an estimated 5-year survival of just 6%. During the last decade, β- or α-emitter-radiolabeled peptides that bind to different receptors on a variety of tumors have been investigated as potential therapeutic agents in both the preclinical and clinical settings with encouraging results. A recent study demonstrated that 188-Rhenium ((188)Re)-labeled, via HYNIC ligand, fungal melanin-binding decapeptide 4B4 was effective against experimental MNT1 human melanoma and was safe to normal melanized tissues. The availability of radiolanthanides with diverse nuclear emission schemes and half-lives provides an opportunity to expand the repertoire of peptides for radionuclide therapy of melanoma. The melanin-binding decapeptide 4B4 was radiolabeled with (177)Lu, (166)Ho, and (153)Sm via a DO3A chelate. The stability studies of Ln*-DO3A-4B4 in phosphate-buffered saline, serum, and a hydroxyapatite assay demonstrated that (177)Lu-labeled peptide was more stable than (166)Ho- and (153)Sm-labeled peptides, most likely because of the smallest ionic radius of the former allowing for better complexation with DO3A. Binding of Ln*-DO3A-4B4 to the lysed highly melanized MNT1 melanoma cells demonstrated the specificity of peptides binding to melanin. In vivo biodistribution data for (177)Lu-DO3A-4B4 given by intraperitoneal administration to lightly pigmented human metastatic A2058 melanoma-bearing mice demonstrated very high uptake in the kidneys and low tumor uptake. Intravenous administration did not improve the tumor uptake. The plausible explanation of low tumor uptake of (177)Lu-DO3A-4B4 could be its decreased ability to bind to melanin during in vitro binding studies in comparison with (188)Re-HYNIC-4B4, exacerbated by the very fast clearance from the blood and the kidneys "sink" effect.
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Affiliation(s)
- Beau Ballard
- Department of Chemistry, Hunter College of the City University of New York, 695 Park Avenue, New York, NY 10065, USA
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23
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Mu L, Honer M, Becaud J, Martic M, Schubiger PA, Ametamey SM, Stellfeld T, Graham K, Borkowski S, Lehmann L, Dinkelborg L, Srinivasan A. In vitro and in vivo characterization of novel 18F-labeled bombesin analogues for targeting GRPR-positive tumors. Bioconjug Chem 2011; 21:1864-71. [PMID: 20857927 DOI: 10.1021/bc100222u] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The gastrin-releasing peptide receptor (GRPR) is overexpressed on a number of human tumors and has been targeted with radiolabeled bombesin analogues for the diagnosis and therapy of these cancers. Seven bombesin analogues containing various linkers and peptide sequences were designed, synthesized, radiolabeled with (18)F, and characterized in vitro and in vivo as potential PET imaging agents. Binding studies displayed nanomolar binding affinities toward human GRPR for all synthesized bombesin analogues. Two high-affinity peptide candidates 6b (K(i) = 0.7 nM) and 7b (K(i) = 0.1 nM) were chosen for further in vivo evaluation. Both tracers revealed specific uptake in GRPR-expressing PC-3 tumors and the pancreas. Compared to [(18)F]6b, compound [(18)F]7b was characterized by superior tumor uptake, higher specificity of tracer uptake, and more favorable tumor-to-nontarget ratios. In vivo PET imaging allowed for the visualization of PC-3 tumor in nude mice suggesting that [(18)F]7b is a promising PET tracer candidate for the diagnosis of GRPR-positive tumors in humans.
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Affiliation(s)
- Linjing Mu
- Center for Radiopharmaceutical Sciences of ETH, PSI and USZ, Zurich, Switzerland
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24
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Wang J, Hu P, Liu B, Jin X, Kong Y, Gao J, Wang D, Wang B, Xu R, Zhang X. Investigation on coordination number and geometrical conformation of rare earth complexes with catenulate aminopolycarboxylic acid ligands. J COORD CHEM 2010. [DOI: 10.1080/00958972.2010.500378] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Jun Wang
- a Department of Chemistry , Liaoning University , Shenyang 110036, P.R. China
| | - Ping Hu
- a Department of Chemistry , Liaoning University , Shenyang 110036, P.R. China
| | - Bin Liu
- b Department of Pharmacy , Liaoning University , Shenyang 110036, P.R. China
| | - Xudong Jin
- a Department of Chemistry , Liaoning University , Shenyang 110036, P.R. China
| | - Yumei Kong
- b Department of Pharmacy , Liaoning University , Shenyang 110036, P.R. China
| | - Jingqun Gao
- a Department of Chemistry , Liaoning University , Shenyang 110036, P.R. China
| | - Dan Wang
- b Department of Pharmacy , Liaoning University , Shenyang 110036, P.R. China
| | - Baoxin Wang
- a Department of Chemistry , Liaoning University , Shenyang 110036, P.R. China
| | - Rui Xu
- a Department of Chemistry , Liaoning University , Shenyang 110036, P.R. China
| | - Xiangdong Zhang
- a Department of Chemistry , Liaoning University , Shenyang 110036, P.R. China
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25
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Cagnolini A, Chen J, Ramos K, Skedzielewski TM, Lantry LE, Nunn AD, Swenson RE, Linder KE. Automated synthesis, characterization and biological evaluation of [(68)Ga]Ga-AMBA, and the synthesis and characterization of (nat)Ga-AMBA and [(67)Ga]Ga-AMBA. Appl Radiat Isot 2010; 68:2285-92. [PMID: 20638858 DOI: 10.1016/j.apradiso.2010.06.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 06/16/2010] [Accepted: 06/24/2010] [Indexed: 10/19/2022]
Abstract
Ga-AMBA (Ga-DO3A-CH(2)CO-G-[4-aminobenzoyl]-QWAVGHLM-NH(2)) is a bombesin-like agonist with high affinity for gastrin releasing peptide receptors (GRP-R). Syntheses for (nat)Ga-AMBA, [(67)Ga]Ga-AMBA and [(68)Ga]Ga-AMBA were developed. The preparation of HPLC-purified and Sep-Pak purified [(68)Ga]Ga-AMBA were fully automated, using the built-in radiodetector of the Tracerlab FX F-N synthesizer to monitor fractionated (68)Ge/(68)Ga generator elution and purification. The total synthesis time, including the fractional elution of the generator, was 20 min for Sep-Pak purified material and 40 min for HPLC-purified [(68)Ga]Ga-AMBA. Both [(67)Ga]Ga-AMBA and [(177)Lu]Lu-AMBA showed comparable high affinity for GRP-R in the human prostate cancer cell line PC-3 in vitro (k(D)=0.46+/-0.07; 0.44+/-0.08 nM), high internalization (78; 77%) and low efflux from cells at 2 h (2.4+/-0.7; 2.9+/-1.8%). Biodistribution results in PC-3 tumor-bearing male nude mice showed comparable uptake for [(177)Lu]Lu-, [(111)In]In-, [(67)Ga]Ga- and [(68)Ga]Ga-AMBA.
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Affiliation(s)
- Aldo Cagnolini
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, NJ 08540, USA
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26
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Linder KE, Metcalfe E, Arunachalam T, Chen J, Eaton SM, Feng W, Fan H, Raju N, Cagnolini A, Lantry LE, Nunn AD, Swenson RE. In vitro and in vivo metabolism of Lu-AMBA, a GRP-receptor binding compound, and the synthesis and characterization of its metabolites. Bioconjug Chem 2009; 20:1171-8. [PMID: 19480415 DOI: 10.1021/bc9000189] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The metabolism of (177)Lu-AMBA (AMBA = DO3A-CH(2)CO-G-(4-aminobenzoyl)-QWAVGHLM-NH(2)), a radiotherapeutic compound in clinical development that binds to GRP and NMB receptors, was studied in vitro (mouse, rat and human plasma, mouse kidney homogenate) and in vivo (by analysis of mouse and rat plasma and urine following IV injection of (177)Lu-AMBA). The primary metabolites were Lu-DO3A-CH(2)CO-G-Abz4-R, where R = -Q-OH (A), -QW-OH (B), and -QWAVGH-OH (C). Minor amounts of (D) where R = -QWAVGHLM-OH and (E) -QWAVGHL-OH were also observed. Clearance of (177)Lu-AMBA and of radioactivity from mouse and rat blood was rapid in vivo. In mouse and rat urine, only metabolites Lu-A and Lu-B were found-no parent drug was excreted. Unmetalated ligands and (nat)Lu and (177)Lu complexes for Lu-AMBA metabolites A-E were synthesized, characterized by HPLC and MS, and used to perform in vitro competition and direct binding studies on GRP receptor-positive PC-3 (human prostate) cancer cells. Biodistribution studies with (177)Lu-labeled metabolites A-E were performed in PC-3 tumor-bearing mice and the results compared with intact (177)Lu-AMBA. IC(50) values for unmetalated metabolite ligands A-E were >400 nM in PC-3 cells in competition binding studies against (177)Lu-AMBA. No direct binding to PC-3 cells was observed with (177)Lu-labeled A-C, confirming IC(50) results. (177)Lu-labeled metabolites A-E showed no uptake in GRP-receptor positive tumor or pancreas in PC-3 tumor bearing mice. All metabolites were rapidly excreted via the renal route (approximately 78-87%) within 1 h. These results demonstrate that the tumor uptake observed with (177)Lu-AMBA is due to parent drug and not due to any of its identified metabolites.
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Affiliation(s)
- Karen E Linder
- Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, USA.
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Abstract
Radiotherapeutic drugs and medical imaging agents, although used for different purposes, both benefit from precise targeting. When systemically administered, either would be most useful if designed to find and bind only a tumor, single type of cell, or unique molecular assembly thereon. In this Account, we examine the use of small peptides, natural and synthetic, to create biochemically specific molecular imaging agents and radiotherapeutic pharmaceuticals, discussing three distinct examples. In one project, a small natural peptide known to target members of the bombesin family of receptors was chemically attached to a strong, versatile metal chelator, DO3A, through a series of small-molecule linkers. The linkers powerfully affected not only binding strength for the bombesin receptors, tissue distribution, and tumor uptake in vivo but also receptor subtype specificity. When the assembly is combined with an active metal ion for human trials, the versatility of the DO3A (dodecanetriacetate) chelate affords choices in selecting the metal ion for different purposes: lutetium for a combination radiotherapeutic and diagnostic agent, (177)Lu-AMBA, and gallium for a positron emission tomography (PET) imaging agent, (68)Ga-AMBA. We also created small (approximately 5-kDa) bivalent peptides, each composed of different chemically linked peptides derived from phage display. The monomer peptides bound to the same target protein, VEGF-R2, a primary target of vascular endothelial growth factor (VEGF), the angiogenesis-stimulating protein. Several families of the monomer peptides did not compete with one another for the binding site on VEGF-R2. Their combination into fully synthetic hetero-bivalent molecules yielded subnanomolar K(d) values and greater than 100-fold improvements over homo-bivalent molecules. Biological activity was evident in the hetero-bivalents, whereas none or very little existed in homo-bivalents, monomers, and monomer mixtures. In ultrasound imaging, tiny bubbles (2 microm in diameter) filled with inert gas can be used as effective contrast agents. By coating the shell of such bubbles with the peptide TKPPR (a tuftsin antagonist), we created contrast agents that bound unexpectedly to cultured endothelial cells expressing angiogenesis targets; the binding was attributable to a previously unnoticed and powerful multivalency effect. TKPPR binds specifically to neuropilin-1 (NP-1), a VEGF co-receptor, but only when multimerized is it avid. Tuftsin, a small peptide derived from immunoglobulin G (IgG) that binds to macrophages during inflammation, has been studied for over 30 years; the receptor has never been cloned. Our results led to new conclusions about tuftsin, NP-1, and the purpose, heretofore unknown, of exon 8 in VEGF, which appears to be involved in NP-1 binding. Our disparate projects demonstrate that small-peptide targeted molecules can be very versatile in drug discovery in combination with classical medicinal chemistry. In particular, multivalent interactions can lead to unpredictable and useful biochemical information, as well as new drug candidates.
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Affiliation(s)
- Michael F. Tweedle
- Departments of Radiology, Chemistry, and Pharmacy; The Ohio State University; Biomedical Research Tower; 460 West 12th Avenue, Columbus, Ohio 43215
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Liu Z, Li ZB, Cao Q, Liu S, Wang F, Chen X. Small-Animal PET of Tumors with 64Cu-Labeled RGD-Bombesin Heterodimer. J Nucl Med 2009; 50:1168-77. [DOI: 10.2967/jnumed.108.061739] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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29
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Cagnolini A, D’Amelio N, Metcalfe E, Nguyen HD, Aime S, Swenson RE, Linder KE. Isolation of a 177Hf Complex Formed by β-Decay of a 177Lu-Labeled Radiotherapeutic Compound and NMR Structural Elucidation of the Ligand and its Lu and Hf Complexes. Inorg Chem 2009; 48:3114-24. [DOI: 10.1021/ic802328a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Aldo Cagnolini
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, Km 163.5, 34012 Basovizza (Trieste), Italy, and Dipartimento di Chimica IFM and Centro di Imaging Molecolare, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - Nicola D’Amelio
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, Km 163.5, 34012 Basovizza (Trieste), Italy, and Dipartimento di Chimica IFM and Centro di Imaging Molecolare, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - Edmund Metcalfe
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, Km 163.5, 34012 Basovizza (Trieste), Italy, and Dipartimento di Chimica IFM and Centro di Imaging Molecolare, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - Hanh D. Nguyen
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, Km 163.5, 34012 Basovizza (Trieste), Italy, and Dipartimento di Chimica IFM and Centro di Imaging Molecolare, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - Silvio Aime
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, Km 163.5, 34012 Basovizza (Trieste), Italy, and Dipartimento di Chimica IFM and Centro di Imaging Molecolare, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - Rolf E. Swenson
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, Km 163.5, 34012 Basovizza (Trieste), Italy, and Dipartimento di Chimica IFM and Centro di Imaging Molecolare, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - Karen E. Linder
- Ernst Felder Laboratories, Bracco Research USA Inc., 305 College Road East, Princeton, New Jersey 08540, Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, Km 163.5, 34012 Basovizza (Trieste), Italy, and Dipartimento di Chimica IFM and Centro di Imaging Molecolare, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
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