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Aalbersberg EA, Cao TT, Geluk-Jonker MM, Hendrikx JJMA. Quality control of [ 177Lu]Lu-PSMA preparations using HPLC: effect of sample composition and ligand on recovery. EJNMMI Radiopharm Chem 2022; 7:24. [PMID: 36166155 PMCID: PMC9515298 DOI: 10.1186/s41181-022-00178-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/14/2022] [Indexed: 12/02/2022] Open
Abstract
Background [177Lu]Lu-PSMA is used for the treatment of metastatic castration-resistant prostate cancer. For in-house productions, quality control methods are essential for ensuring product quality, and thus patient safety. During HPLC method development for quality control of [177Lu]Lu-PSMA-I&T, we noticed an unpredictable variability in peak area and height with replicate measurements. After a run, irremovable radioactivity was measured over the whole the length of the HPLC column, with slightly higher activity at the beginning and end of the column. The uniform distribution suggests that [177Lu]Lu-PSMA-I&T interacts with the column. As a result of the interaction, incomplete and variable recovery of injected activity was observed leading to the variability in peak area and height. Therefore the aim of this study was to (1) investigate the effect of sample composition on the interaction of [177Lu]Lu-PSMA-I&T to the HPLC column (measured as recovery, peak area, and peak height), and (2) to compare this with same concentrations of the well-known [177Lu]Lu-PSMA-617. Results Sample composition significantly affects recovery of [177Lu]Lu-PSMA-I&T, leading to a change in peak area and height. Recovery was 24% when diluted with 0.1 mM octreotide, 38% with water, and increased to 95% when diluted with 0.7 mM unlabeled PSMA-I&T. Peak area and height decreased to 26% and 17% when diluted in octreotide and to 41% and 29% when diluted in water, compared to a dilution in PSMA-I&T. Further experiments showed that recovery (and consequently peak area and peak height) reached a plateau of > 99% at concentrations of 0.27 mM and higher. [177Lu]Lu-PSMA-617 also interacts with the HPLC column, leading to lower, but less variable, recovery (9%). The low recovery of [177Lu]Lu-PSMA-617 could not be prevented with addition of unlabeled PSMA-617. Conclusion [177Lu]Lu-PSMA-I&T can undergo an irreversible binding with an HPLC column resulting in a decreased recovery. The recovery is can be highly dependent on sample composition. The addition of a surplus of unlabeled PSMA-I&T leads to an accurate analysis of [177Lu]Lu-PSMA-I&T.
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Affiliation(s)
- Else A Aalbersberg
- Department of Nuclear Medicine, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
| | - Tammie T Cao
- Department of Nuclear Medicine, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.,Department of Pharmacology, OLVG Locatie West, Jan Tooropstraat 164, 1061 AE, Amsterdam, The Netherlands
| | - Martine M Geluk-Jonker
- Department of Nuclear Medicine, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.,Department of Pharmacy and Pharmacology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Jeroen J M A Hendrikx
- Department of Nuclear Medicine, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.,Department of Pharmacy and Pharmacology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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Blocking Studies to Evaluate Receptor-Specific Radioligand Binding in the CAM Model by PET and MR Imaging. Cancers (Basel) 2022; 14:cancers14163870. [PMID: 36010864 PMCID: PMC9406147 DOI: 10.3390/cancers14163870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/05/2022] [Indexed: 02/06/2023] Open
Abstract
Simple Summary In the development of new targeted radiopharmaceuticals, it is mandatory to demonstrate their target-specific binding. Rodents are still primarily used for these experiments. With respect to the 3Rs principles, the demand for alternative methods to reduce the number of animal experiments is continuously increasing. In the present study, we investigated whether radiotracer uptake specificity can be evaluated by blocking studies in the CAM model. PET and MR imaging were used to visualize and quantify ligand accumulation. It was demonstrated that the CAM model could be used to evaluate the target-specific binding of a radiopharmaceutical. Due to intrinsic limitations of the CAM model, animal testing will still be required at more advanced stages of compound development. Still, the CAM model could significantly reduce the number of experiments through early compound pre-selection. Abstract Inhibition studies in small animals are the standard for evaluating the specificity of newly developed drugs, including radiopharmaceuticals. Recently, it has been reported that the tumor accumulation of radiotracers can be assessed in the chorioallantoic membrane (CAM) model with similar results to experiments in mice, such contributing to the 3Rs principles (reduction, replacement, and refinement). However, inhibition studies to prove receptor-specific binding have not yet been performed in the CAM model. Thus, in the present work, we analyzed the feasibility of inhibition studies in ovo by PET and MRI using the PSMA-specific ligand [18F]siPSMA-14 and the corresponding inhibitor 2-PMPA. A dose-dependent blockade of [18F]siPSMA-14 uptake was successfully demonstrated by pre-dosing with different inhibitor concentrations. Based on these data, we conclude that the CAM model is suitable for performing inhibition studies to detect receptor-specific binding. While in the later stages of development of novel radiopharmaceuticals, testing in rodents will still be necessary for biodistribution analysis, the CAM model is a promising alternative to mouse experiments in the early phases of compound evaluation. Thus, using the CAM model and PET and MR imaging for early pre-selection of promising radiolabeled compounds could significantly reduce the number of animal experiments.
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45Ti targeted tracers for PET imaging of PSMA. Nucl Med Biol 2022; 108-109:16-23. [DOI: 10.1016/j.nucmedbio.2022.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/22/2021] [Accepted: 01/31/2022] [Indexed: 11/18/2022]
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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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Urbanová K, Seifert D, Vinšová H, Vlk M, Lebeda O. Simple new method for labelling of PSMA-11 with 68Ga in NaHCO 3. Appl Radiat Isot 2021; 172:109692. [PMID: 33770721 DOI: 10.1016/j.apradiso.2021.109692] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 02/22/2021] [Accepted: 03/13/2021] [Indexed: 12/18/2022]
Abstract
BACKGROUND Prostate specific membrane antigen (PSMA) is a type II membrane protein widely expressed on the surface of prostate cancer cells. One of its functions is to act as a receptor mediating the ligand internalization. This PSMA property is employed in the diagnostics and therapy of prostate cancer. Over the years, small molecules with high affinity for PSMA have been developed and labelled with positron emitters (e.g. 68Ga, 18F, 11C, 64Cu, or 86Y). One of these radiolabelled ligands, [68Ga] PSMA-11, is one of the most widespread tracers for PET imaging of the prostate cancer. Many techniques have been proposed and tested for the 68Ga labelling of PSMA-11. The aim of our work was to design a labelling method of PSMA-11 that minimizes number of the used chemicals and steps, providing quantitative labelling yield at laboratory temperature and may be easily automated. METHODOLOGY A68Ge/68Ga generator eluate in 0.1 M HCl was loaded on an activated Oasis MCX cartridge, and the cartridge was then thoroughly washed with water. The radionuclide 68Ga was eluted from the cartridge with 0.1 M NaHCO3 (pH = 8.5, n = 36) or with the same solution with pH adjusted to 7.2-9.0 (n = 38). Precursor PSMA-11 was mixed directly with the cartridge eluate of 68Ga in 0.1 M NaHCO3 of given pH. For the stability test, samples of 68GaPSMA-11 in 0.1 M NaHCO3 (pH 8.5) were mixed in ratio 1 : 1 with the following solutions: 0.1 M NaHCO3 (pH 8.5), human serum, PBS and 0.9% NaCl. In order to estimate an effect of the time elapsed between 68Ga elution from the cartridge in 0.1 M NaHCO3 (pH 8.5) and the labelling onset of PSMA-11, the latter was initiated 0, 5, 10 and 20 min post elution and radiochemical yield was monitored. All the PSMA-11 labelled samples were subjected to radiochemical purity test using HPLC. The whole process starting from generator elution up to HPLC analysis commencement took 10-15 min. RESULTS Recovery of 68Ga from cartridge Oasis MCX using 0.1 M NaHCO3 at pH 8.5 was 71.5 ± 1.4%. Thirty six PSMA-11 samples (10 μg in reaction mixture) were labelled at pH 8.5 with total average radiochemical yield of 98 ± 2%. Recovery of 68Ga from cartridge Oasis MCX using 0.1 M NaHCO3 at variable pH of 7.2-9.0 was 62.5 ± 1.8% showing certain decrease with decreasing pH. A total of 138 samples of PSMA-11 were labelled with 68 Ga at variable pH (7.2-9.0) and four different amounts of PSMA-11 (1, 2.5, 5 and 10 μg) resulting in the labelling yields of 54.0 ± 5.3%, 88.2 ± 3.2%, 99.4 ± 0.3% and 99.9 ± 0.1%, respectively. Irrespective of the pH, the radiolabelling yield was quantitative for the molar ratio PSMA-11: 68Ga > 5000 : 1 in the reaction mixture. Stability tests in 0.1 M NaHCO3 (pH 8.5), human serum, PBS and 0.9% NaCl revealed no observable release of 68Ga from the 68Ga-PSMA-11 complex within 3 h. Similarly, the delay between the 68Ga elution from the Oasis MCX cartridge in 0.1 M NaHCO3 (pH 8.5) and start of the labelling of PSMA-11 labelling has no effect on the radiochemical yield. CONCLUSION A new method of labelling PSMA-11 ligand with 68Ga in 0.1 M NaHCO3 using Oasis MCX cartridges was proposed, developed and tested. The results demonstrated that it is rapid, simple, reproducible and easy to automate.
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Affiliation(s)
- Kamila Urbanová
- Department of Radiopharmaceuticals, Nuclear Physic Institute, Czech Academy of Sciences, Řež, Czech Republic; Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague, Czech Republic
| | - Daniel Seifert
- Department of Radiopharmaceuticals, Nuclear Physic Institute, Czech Academy of Sciences, Řež, Czech Republic
| | - Hana Vinšová
- Department of Radiopharmaceuticals, Nuclear Physic Institute, Czech Academy of Sciences, Řež, Czech Republic
| | - Martin Vlk
- Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague, Czech Republic
| | - Ondřej Lebeda
- Department of Radiopharmaceuticals, Nuclear Physic Institute, Czech Academy of Sciences, Řež, Czech Republic.
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Garnuszek P, Karczmarczyk U, Maurin M, Sikora A, Zaborniak J, Pijarowska-Kruszyna J, Jaroń A, Wyczółkowska M, Wojdowska W, Pawlak D, Lipiński PFJ, Mikołajczak R. PSMA-D4 Radioligand for Targeted Therapy of Prostate Cancer: Synthesis, Characteristics and Preliminary Assessment of Biological Properties. Int J Mol Sci 2021; 22:2731. [PMID: 33800517 PMCID: PMC7962978 DOI: 10.3390/ijms22052731] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 12/25/2022] Open
Abstract
A new PSMA ligand (PSMA-D4) containing the Glu-CO-Lys pharmacophore connected with a new linker system (L-Trp-4-Amc) and chelator DOTA was developed for radiolabeling with therapeutic radionuclides. Herein we describe the synthesis, radiolabeling, and preliminary biological evaluation of the novel PSMA-D4 ligand. Synthesized PSMA-D4 was characterized using TOF-ESI-MS, NMR, and HPLC methods. The novel compound was subject to molecular modeling with GCP-II to compare its binding mode to analogous reference compounds. The radiolabeling efficiency of PSMA-D4 with 177Lu, 90Y, 47Sc, and 225Ac was chromatographically tested. In vitro studies were carried out in PSMA-positive LNCaP tumor cells membranes. The ex vivo tissue distribution profile of the radioligands and Cerenkov luminescence imaging (CLI) was studied in LNCaP tumor-bearing mice. PSMA-D4 was synthesized in 24% yield and purity >97%. The radio complexes were obtained with high yields (>97%) and molar activity ranging from 0.11 to 17.2 GBq mcmol-1, depending on the radionuclide. In vitro assays confirmed high specific binding and affinity for all radiocomplexes. Biodistribution and imaging studies revealed high accumulation in LNCaP tumor xenografts and rapid clearance of radiocomplexes from blood and non-target tissues. These render PSMA-D4 a promising ligand for targeted therapy of prostate cancer (PCa) metastases.
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Affiliation(s)
- Piotr Garnuszek
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Urszula Karczmarczyk
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Michał Maurin
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Arkadiusz Sikora
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | | | - Justyna Pijarowska-Kruszyna
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Antoni Jaroń
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Monika Wyczółkowska
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Wioletta Wojdowska
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Dariusz Pawlak
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
| | - Piotr F. J. Lipiński
- Department of Neuropeptides, Mossakowski Medical Research Center Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Renata Mikołajczak
- National Centre for Nuclear Research, Radioisotope Centre POLATOM, 05-400 Otwock, Poland; (P.G.); (M.M.); (A.S.); (J.P.-K.); (A.J.); (M.W.); (W.W.); (D.P.); (R.M.)
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Wichmann CW, Ackermann U, Poniger S, Young K, Nguyen B, Chan G, Sachinidis J, Scott AM. Automated radiosynthesis of [ 68 Ga]Ga-PSMA-11 and [ 177 Lu]Lu-PSMA-617 on the iPHASE MultiSyn module for clinical applications. J Labelled Comp Radiopharm 2021; 64:140-146. [PMID: 33067810 PMCID: PMC8048907 DOI: 10.1002/jlcr.3889] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/10/2020] [Accepted: 08/27/2020] [Indexed: 11/11/2022]
Abstract
Prostate-specific membrane antigen (PSMA)-targeted imaging and therapy of prostate cancer using theranostic pairs is rapidly changing clinical practice. To facilitate clinical trials, fully automated procedures for the radiosyntheses of [68 Ga]Ga-PSMA-11 and [177 Lu]Lu-PSMA-617 were developed from commercially available precursors using the cassette based iPHASE MultiSyn module. Formulated and sterile radiopharmaceuticals were obtained in 76 ± 3% (n = 20) and 91 ± 4% (n = 15) radiochemical yields after 17 and 20 min, respectively. Radiochemical purity was always >95% and molar activities exceeded 792 ± 100 and 88 ± 6 GBq/μmol, respectively. Quality control showed conformity with all relevant release criteria and radiopharmaceuticals were used in the clinic.
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Affiliation(s)
- Christian W. Wichmann
- Tumor Targeting LaboratoryOlivia Newton‐John Cancer Research InstituteHeidelbergVictoriaAustralia
- School of Cancer MedicineLa Trobe UniversityBundooraVictoriaAustralia
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
- Department of MedicineUniversity of MelbourneParkvilleVictoriaAustralia
| | - Uwe Ackermann
- Tumor Targeting LaboratoryOlivia Newton‐John Cancer Research InstituteHeidelbergVictoriaAustralia
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
- Department of MedicineUniversity of MelbourneParkvilleVictoriaAustralia
| | - Stan Poniger
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
| | - Kenneth Young
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
| | - Benjamin Nguyen
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
| | - Gordon Chan
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
| | - John Sachinidis
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
| | - Andrew M. Scott
- Tumor Targeting LaboratoryOlivia Newton‐John Cancer Research InstituteHeidelbergVictoriaAustralia
- School of Cancer MedicineLa Trobe UniversityBundooraVictoriaAustralia
- Department of Molecular Imaging and TherapyAustin HealthHeidelbergVictoriaAustralia
- Department of MedicineUniversity of MelbourneParkvilleVictoriaAustralia
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Intra-individual dynamic comparison of 18F-PSMA-11 and 68Ga-PSMA-11 in LNCaP xenograft bearing mice. Sci Rep 2020; 10:21068. [PMID: 33273603 PMCID: PMC7713063 DOI: 10.1038/s41598-020-78273-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/20/2020] [Indexed: 02/08/2023] Open
Abstract
Recently, a 18F-labeled derivative of the widely used 68Ga-PSMA-11 was developed for PET imaging of prostate cancer. Although 18F-PSMA-11 has already been evaluated in a Phase I and Phase II clinical trial, preclinical evaluation of this radiotracer is important for further understanding its dynamic behavior. Saturation binding experiments were conducted by incubation of LNCaP cells with 18F-PSMA-11 or 68Ga-PSMA-11 for 1 h, followed by determination of the specific and aspecific binding. Mice bearing LNCaP or PC-3 xenografts each received ± 3.7 MBq 18F-PSMA-11 and 68Ga-PSMA-11 followed by dynamic acquisition of 2.5 h as well as ± 15 MBq 18F-FDG followed by static acquisition at 1 h post injection (p.i.). Uptake was evaluated by comparison of uptake parameters (SUVmean, SUVmax, TBRmean and TBRmax). Mice underwent ex vivo biodistribution where 18F-PSMA-11 activity was measures in excretory organs (kidneys, bladder and liver) as well as bone fragments (femur, humerus, sternum and skull) to evaluate bone uptake. The dissociation constant (Kd) of 18F-PSMA-11 and 68Ga-PSMA-11 was 2.95 ± 0.87 nM and 0.49 ± 0.20 nM, respectively. Uptake parameters were significantly higher in LNCaP compared to PC-3 xenografts for both 18F-PSMA-11 and 68Ga-PSMA-11, while no difference was found for 18F-FDG uptake (except for SUVmax). Tumor uptake of 18F-PSMA-11 showed a similar trend over time as 68Ga-PSMA-11, although all uptake parameter curves of the latter were considerably lower. When comparing early (60 min p.i.) to delayed (150 min p.i.) imaging for both radiotracers individually, TBRmean and TBRmax were significantly higher at the later timepoint, as well as the SUVmax of 68Ga-PSMA-11. The highest %ID/g was determined in the kidneys (94.0 ± 13.6%ID/g 1 h p.i.) and the bladder (6.48 ± 2.18%ID/g 1 h p.i.). No significant increase in bone uptake was seen between 1 and 2 h p.i. Both radiotracers showed high affinity for the PSMA receptor. Over time, all uptake parameters were higher for 18F-PSMA-11 compared to 68Ga-PSMA-11. Delayed imaging with the latter may improve tumor visualization, while no additional benefits could be found for late 18F-PSMA-11 imaging. Ex vivo biodistribution demonstrated fast renal clearance of 18F-PSMA-11 as well as no significant increase in bone uptake.
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Reverchon J, Khayi F, Roger M, Moreau A, Kryza D. Optimization of the radiosynthesis of [68Ga]Ga-PSMA-11 using a Trasis MiniAiO synthesizer: do we need to heat and purify? Nucl Med Commun 2020; 41:977-985. [PMID: 32796487 DOI: 10.1097/mnm.0000000000001233] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUTION:: [Ga]Ga-prostate specific membrane antigen (PSMA)-11 showed a clear gain in sensitivity for lesion detection in the biological recurrence of prostate cancer as compared to the standard [F]fluorocholine radiopharmaceutical. To meet the strong demand for [Ga]Ga-PSMA-11, we aimed to optimize an automated radiolabeling process by evaluating the influence of different key parameters on radiochemical purity and radiochemical yield. METHODS The radiosynthesis of [Ga]Ga PSMA-11 was performed using a Trasis MiniAio synthesizer and a Ge/Ga GalliaPharm generator supplied by Eckert & Ziegler, Berlin, Germany. Optimized labeling parameters were evaluated by variation of sodium acetate concentrations and temperature of radiolabeling as well as the purification process. RESULTS For each condition tested, radiochemical purity was higher than 99% in the final vial without batch failure, indicating a robust and fast radiosynthesis process. Radiosynthesis without the solid phase extraction purification process at room temperature in less than 5 min resulted in a radiolabeling efficiency of over 99% and remained stable at least 4 h without manual processing to limit operator radiation exposure. CONCLUSION The procedure was completely automated and provided a high radiochemical yield. It can be performed several times a day, facilitating the clinical demand of this radiopharmaceutical.
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Affiliation(s)
| | - Fouzi Khayi
- Department of Lumen Nuclear medicine, Centre Léon Bérard, Lyon
| | - Marianne Roger
- Department of Lumen Nuclear medicine, Centre Léon Bérard, Lyon
| | - Aurélie Moreau
- Department of Lumen Nuclear medicine, Centre Léon Bérard, Lyon
| | - David Kryza
- UNIV Lyon - Université Claude Bernard Lyon 1, LAGEPP UMR 5007 CNRS Villeurbanne
- Hospices Civils de Lyon, 69437 Lyon, France
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Winter G, Koch ABF, Löffler J, Lindén M, Solbach C, Abaei A, Li H, Glatting G, Beer AJ, Rasche V. Multi-Modal PET and MR Imaging in the Hen's Egg Test-Chorioallantoic Membrane (HET-CAM) Model for Initial in Vivo Testing of Target-Specific Radioligands. Cancers (Basel) 2020; 12:cancers12051248. [PMID: 32429233 PMCID: PMC7281765 DOI: 10.3390/cancers12051248] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/17/2022] Open
Abstract
The validation of novel target-specific radioligands requires animal experiments mostly using mice with xenografts. A pre-selection based on a simpler in vivo model would allow to reduce the number of animal experiments, in accordance with the 3Rs principles (reduction, replacement, refinement). In this respect, the chick embryo or hen’s egg test–chorioallantoic membrane (HET-CAM) model is of special interest, as it is not considered an animal until day 17. Thus, we evaluated the feasibility of quantitative analysis of target-specific radiotracer accumulation in xenografts using the HET-CAM model and combined positron emission tomography (PET) and magnetic resonance imaging (MRI). For proof-of-principle we used established prostate-specific membrane antigen (PSMA)-positive and PSMA-negative prostate cancer xenografts and the clinically widely used PSMA-specific PET-tracer [68Ga]Ga-PSMA-11. Tracer accumulation was quantified by PET and tumor volumes measured with MRI (n = 42). Moreover, gamma-counter analysis of radiotracer accumulation was done ex-vivo. A three- to five-fold higher ligand accumulation in the PSMA-positive tumors compared to the PSMA-negative tumors was demonstrated. This proof-of-principle study shows the general feasibility of the HET-CAM xenograft model for target-specific imaging with PET and MRI. The ultimate value for characterization of novel target-specific radioligands now has to be validated in comparison to mouse xenograft experiments.
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Affiliation(s)
- Gordon Winter
- Department of Nuclear Medicine, Ulm University Medical Center, 89081 Ulm, Germany; (A.B.F.K.); (J.L.); (C.S.); (A.J.B.)
- Correspondence: (G.W.); (V.R.); Tel.: +49-731-500-61364 (G.W.); +49-731-500-45014 (V.R.)
| | - Andrea B. F. Koch
- Department of Nuclear Medicine, Ulm University Medical Center, 89081 Ulm, Germany; (A.B.F.K.); (J.L.); (C.S.); (A.J.B.)
| | - Jessica Löffler
- Department of Nuclear Medicine, Ulm University Medical Center, 89081 Ulm, Germany; (A.B.F.K.); (J.L.); (C.S.); (A.J.B.)
- Core Facility Small Animal Imaging, Ulm University Medical Center, 89081 Ulm, Germany; (A.A.); (H.L.)
| | - Mika Lindén
- Department of Inorganic Chemistry II, Ulm University, 89081 Ulm, Germany;
| | - Christoph Solbach
- Department of Nuclear Medicine, Ulm University Medical Center, 89081 Ulm, Germany; (A.B.F.K.); (J.L.); (C.S.); (A.J.B.)
| | - Alireza Abaei
- Core Facility Small Animal Imaging, Ulm University Medical Center, 89081 Ulm, Germany; (A.A.); (H.L.)
| | - Hao Li
- Core Facility Small Animal Imaging, Ulm University Medical Center, 89081 Ulm, Germany; (A.A.); (H.L.)
| | - Gerhard Glatting
- Department of Nuclear Medicine, Medical Radiation Physics, Ulm University Medical Center, 89081 Ulm, Germany;
| | - Ambros J. Beer
- Department of Nuclear Medicine, Ulm University Medical Center, 89081 Ulm, Germany; (A.B.F.K.); (J.L.); (C.S.); (A.J.B.)
| | - Volker Rasche
- Core Facility Small Animal Imaging, Ulm University Medical Center, 89081 Ulm, Germany; (A.A.); (H.L.)
- Internal Medicine II, Ulm University Medical Center, 89081 Ulm, Germany
- Correspondence: (G.W.); (V.R.); Tel.: +49-731-500-61364 (G.W.); +49-731-500-45014 (V.R.)
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A comparative study of peptide-based imaging agents [ 68Ga]Ga-PSMA-11, [ 68Ga]Ga-AMBA, [ 68Ga]Ga-NODAGA-RGD and [ 68Ga]Ga-DOTA-NT-20.3 in preclinical prostate tumour models. Nucl Med Biol 2020; 84-85:88-95. [PMID: 32251995 DOI: 10.1016/j.nucmedbio.2020.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 03/20/2020] [Accepted: 03/24/2020] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Peptide-based imaging agents targeting prostate-specific membrane antigen (PSMA) have revolutionized the evaluation of biochemical recurrence of prostate cancer (PCa) but lacks sensitivity at very low serum prostate specific antigen (PSA) levels. Once recurrence is suspected, other positron emission tomography (PET) radiotracers could be of interest to discriminate between local and distant relapse. We studied [18F]fluorodeoxyglucose ([18F]FDG) targeting glucose metabolism, [18F]fluorocholine ([18F]FCH) targeting membrane metabolism and peptide-based imaging agents [68Ga]Ga-PSMA-11, [68Ga]Ga-AMBA, [68Ga]Ga-NODAGA-RGD and [68Ga]Ga-DOTA-NT-20.3 targeting PSMA, gastrin releasing peptide receptor (GRPr), αvβ3 integrin and neurotensin type 1 receptor (NTSR1) respectively, in different PCa tumour models. METHODS Mice were xenografted with 22Rv1, an androgen-receptor (AR)-positive, PCa cell line that expresses PSMA and PC3, an AR-negative one that does not express PSMA. PET imaging using the different radiotracers was performed sequentially and the uptake characteristics compared to one other. NTSR1 and PSMA expression levels were analysed in tumours by immunohistochemistry. RESULTS [18F]FDG displayed low but sufficient uptake to visualize PC3 and 22Rv1 derived tumours. We also observed a low efficacy of [18F]FCH PET imaging and a low [68Ga]Ga-NODAGA-RGD tumour uptake in those tumours. As expected, an elevated tumour uptake was obtained for [68Ga]Ga-PSMA-11 in 22Rv1 derived tumour although no uptake was measured in the androgen independent cell line PC3, derived from a bone metastasis of a high-grade PCa. Moreover, in PC3 cell line, we obtained good tumour uptake, high tumour-to-background contrast using [68Ga]Ga-AMBA and [68Ga]Ga-DOTA-NT-20.3. Immunohistochemistry analysis confirmed high NTSR1 expression in PC3 derived tumours and conversely high PSMA expression in 22Rv1 derived tumours. CONCLUSION PET imaging using [68Ga]Ga-AMBA and [68Ga]Ga-DOTA-NT-20.3 demonstrates that GRPr and NTSR1 could represent viable alternative targets for diagnostic or therapeutic applications in PCa with limited PSMA expression levels. More preclinical and clinical studies will follow to explore this potential. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT Peptide-based imaging agents targeting PSMA represent a major progress in the evaluation of biochemical recurrence of PCa but sometimes yield false negative results in some lesions. Continuing efforts have thus been made to evaluate other radiotracers. Our preclinical results suggest that [68Ga]labelled bombesin and neurotensin analogues could serve as alternative PET radiopharmaceuticals for diagnostic or therapy in cases of PSMA-negative PCa.
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12
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Wang S, Blaha C, Santos R, Huynh T, Hayes TR, Beckford-Vera DR, Blecha JE, Hong AS, Fogarty M, Hope TA, Raleigh DR, Wilson DM, Evans MJ, VanBrocklin HF, Ozawa T, Flavell RR. Synthesis and Initial Biological Evaluation of Boron-Containing Prostate-Specific Membrane Antigen Ligands for Treatment of Prostate Cancer Using Boron Neutron Capture Therapy. Mol Pharm 2019; 16:3831-3841. [PMID: 31381351 DOI: 10.1021/acs.molpharmaceut.9b00464] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Boron neutron capture therapy (BNCT) is a therapeutic modality which has been used for the treatment of cancers, including brain and head and neck tumors. For effective treatment via BNCT, efficient and selective delivery of a high boron dose to cancer cells is needed. Prostate-specific membrane antigen (PSMA) is a target for prostate cancer imaging and drug delivery. In this study, we conjugated boronic acid or carborane functional groups to a well-established PSMA inhibitor scaffold to deliver boron to prostate cancer cells and prostate tumor xenograft models. Eight boron-containing PSMA inhibitors were synthesized. All of these compounds showed a strong binding affinity to PSMA in a competition radioligand binding assay (IC50 from 555.7 to 20.3 nM). Three selected compounds 1a, 1d, and 1f were administered to mice, and their in vivo blocking of 68Ga-PSMA-11 uptake was demonstrated through a positron emission tomography (PET) imaging and biodistribution experiment. Biodistribution analysis demonstrated boron uptake of 4-7 μg/g in 22Rv1 prostate xenograft tumors and similar tumor/muscle ratios compared to the ratio for the most commonly used BNCT compound, 4-borono-l-phenylalanine (BPA). Taken together, these data suggest a potential role for PSMA targeted BNCT agents in prostate cancer therapy following suitable optimization.
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Affiliation(s)
- Sinan Wang
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Charles Blaha
- Department of Bioengineering and Therapeutic Sciences , University of California , San Francisco , California , United States
| | - Raquel Santos
- Department of Neurological Surgery , University of California , San Francisco , California , United States
| | - Tony Huynh
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Thomas R Hayes
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Denis R Beckford-Vera
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Joseph E Blecha
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Andrew S Hong
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Miko Fogarty
- Department of Neurological Surgery , University of California , San Francisco , California , United States
| | - Thomas A Hope
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - David R Raleigh
- Department of Neurological Surgery , University of California , San Francisco , California , United States.,Departments of Radiation Oncology , University of California , San Francisco , California , United States
| | - David M Wilson
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Michael J Evans
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Henry F VanBrocklin
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States
| | - Tomoko Ozawa
- Department of Neurological Surgery , University of California , San Francisco , California , United States
| | - Robert R Flavell
- Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States.,Department of Pharmaceutical Chemistry , University of California , San Francisco , California , United States
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Chakravarty R, Siamof CM, Dash A, Cai W. Targeted α-therapy of prostate cancer using radiolabeled PSMA inhibitors: a game changer in nuclear medicine. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2018; 8:247-267. [PMID: 30245917 PMCID: PMC6146164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/13/2018] [Indexed: 06/08/2023]
Abstract
Prostate cancer (PCa) is one of the most common malignancies in men and is a major contributor to cancer related deaths worldwide. Metastatic spread and disease progression under androgen deprivation therapy signify the onset of metastatic castration resistant prostate cancer (mCRPCa)-the lethal form of the disease, which severely deteriorates the quality of life of patients. Over the last decade, tremendous progress has been made toward identifying appropriate molecular targets that could enable efficient in vivo targeting for non-invasive imaging and therapy of mCPRCa. In this context, a promising enzymatic target is prostate specific membrane antigen (PSMA), which is overexpressed on PCa cells, in proportion to the stage and grade of the tumor progression. This is especially relevant for mCRPCa, which has significant overexpression of PSMA. For therapy of mCRPCa, several nuclear medicine clinics all over the world have confirmed that 177Lu-labeled-PSMA enzyme inhibitors (177Lu-PSMA-617 and 177Lu-PSMA I&T) have a favorable dosimetry and convincing therapeutic response. However, ~30% of patients were found to be short or non-responders and dose escalation was severely limited by chronic hematological toxicity. Such limitations could be better overcome by targeted alpha therapy (TAT) which has the potential to bring a paradigm shift in treatment of mCRPCa patients. This concise review presents an overview of the successes and challenges currently faced in TAT of mCRPCa using radiolabeled PSMA inhibitors. The preclinical and clinical data reported to date are quite promising, and it is expected that this therapeutic modality will play a pivotal role in advanced stage PCa management in the foreseeable future.
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Affiliation(s)
- Rubel Chakravarty
- Radiopharmaceuticals Division, Bhabha Atomic Research CentreMumbai 400085, India
- Homi Bhabha National InstituteAnushaktinagar, Mumbai 400094, India
| | - Cerise M Siamof
- Department of Radiology, University of Wisconsin-MadisonWI 53792-3252, USA
| | - Ashutosh Dash
- Radiopharmaceuticals Division, Bhabha Atomic Research CentreMumbai 400085, India
- Homi Bhabha National InstituteAnushaktinagar, Mumbai 400094, India
| | - Weibo Cai
- Department of Radiology, University of Wisconsin-MadisonWI 53792-3252, USA
- Department of Medical Physics, University of Wisconsin-MadisonWI 53705-2275, USA
- Carbone Cancer Center, University of Wisconsin-MadisonWI 53792-3252, USA
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