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Lall R, Lee K, Chopra S, Kandala A, Evans M, Seo Y, Niknejad A, Anwar M. Low cost, high temporal resolution optical fiber-based γ-photon sensor for real-time pre-clinical evaluation of cancer-targeting radiopharmaceuticals. Biosens Bioelectron 2024; 247:115956. [PMID: 38145595 DOI: 10.1016/j.bios.2023.115956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/17/2023] [Accepted: 12/20/2023] [Indexed: 12/27/2023]
Abstract
Cancer radiopharmaceutical therapies (RPTs) have demonstrated great promise in the treatment of neuroendocrine and prostate cancer, giving hope to late-stage metastatic cancer patients with currently very few treatment options. These therapies have sparked a large amount of interest in pre-clinical research due to their ability to target metastatic disease, with many research efforts focused towards developing and evaluating targeted RPTs for different cancer types in in vivo models. Here we describe a method for monitoring real-time in vivo binding kinetics for the pre-clinical evaluation of cancer RPTs. Recognizing the significant heterogeneity in biodistribution of RPTs among even genetically identical animal models, this approach offers long-term monitoring of the same in vivo organism without euthanasia in contrast to ex vivo tissue dosimetry, while providing high temporal resolution with a low-cost, easily assembled platform, that is not present in small-animal SPECT/CTs. The method utilizes the developed optical fiber-based γ-photon biosensor, characterized to have a wide linear dynamic range with Lutetium-177 (177Lu) activity (0.5-500 μCi/mL), a common radioisotope used in cancer RPT. The probe's ability to track in vivo uptake relative to SPECT/CT and ex vivo dosimetry techniques was verified by administering 177Lu-PSMA-617 to mouse models bearing human prostate cancer tumors (PC3-PIP, PC3-flu). With this method for monitoring RPT uptake, it is possible to evaluate changes in tissue uptake at temporal resolutions <1 min to determine RPT biodistribution in pre-clinical models and better understand dose relationships with tumor ablation, toxicity, and recurrence when attempting to move therapies towards clinical trial validation.
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Affiliation(s)
- Rahul Lall
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, 94720, USA.
| | - Kyoungtae Lee
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA, 94107, USA
| | - Shalini Chopra
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, 94107, USA
| | - Averal Kandala
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Michael Evans
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, 94107, USA
| | - Youngho Seo
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, 94107, USA
| | - Ali Niknejad
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Mekhail Anwar
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, 94720, USA; Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA, 94107, USA
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Bolzati C, Gobbi C, Ferro-Flores G, Turato S, Ocampo-Garcia B, Carpanese D, Marzano C, Spolaore B, Fracasso G, Rosato A, Meléndez-Alafort L. Development and Characterization of 99mTc-scFvD2B as a Potential Radiopharmaceutical for SPECT Imaging of Prostate Cancer. Int J Mol Sci 2023; 25:492. [PMID: 38203663 PMCID: PMC10779128 DOI: 10.3390/ijms25010492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
Previously, we demonstrated that the 177Lu-labeled single-chain variable fragment of an anti-prostate-specific membrane antigen (PSMA) IgG D2B antibody (scFvD2B) showed higher prostate cancer (PCa) cell uptake and tumor radiation doses compared to 177Lu-labeled Glu-ureide-based PSMA inhibitory peptides. To obtain a 99mTc-/177Lu-scFvD2B theranostic pair, this research aimed to synthesize and biochemically characterize a novel 99mTc-scFvD2B radiotracer. The scFvD2B-Tag and scFvD2B antibody fragments were produced and purified. Then, two HYNIC derivatives, HYNIC-Gly-Gly-Cys-NH2 (HYNIC-GGC) and succinimidyl-HYNIC (S-HYNIC), were used to conjugate the scFvD2B-Tag and scFvD2B isoforms, respectively. Subsequently, chemical characterization, immunoreactivity tests (affinity and specificity), radiochemical purity tests, stability tests in human serum, cellular uptake and internalization in LNCaP(+), PC3-PIP(++) or PC3(-) PCa cells of the resulting unlabeled HYNIC-scFvD2B conjugates (HscFv) and 99mTc-HscFv agents were performed. The results showed that incorporating HYNIC as a chelator did not affect the affinity, specificity or stability of scFvD2B. After purification, the radiochemical purity of 99mTc-HscFv radiotracers was greater than 95%. A two-sample t-test of 99mTc-HscFv1 and 99mTc-HscFv1 uptake in PC3-PIP vs. PC3 showed a p-value < 0.001, indicating that the PSMA receptor interaction of 99mTc-HscFv agents was statistically significantly higher in PSMA-positive cells than in the negative controls. In conclusion, the results of this research warrant further preclinical studies to determine whether the in vivo pharmacokinetics and tumor uptake of 99mTc-HscFv still offer sufficient advantages over HYNIC-conjugated peptides to be considered for SPECT/PSMA imaging.
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Affiliation(s)
- Cristina Bolzati
- Institute of Condensed Matter Chemistry and Energy Technologies, Consiglio Nazionale delle Ricerche, Corso Stati Uniti 4, 35127 Padova, Italy; (C.B.); (C.G.)
| | - Carolina Gobbi
- Institute of Condensed Matter Chemistry and Energy Technologies, Consiglio Nazionale delle Ricerche, Corso Stati Uniti 4, 35127 Padova, Italy; (C.B.); (C.G.)
| | - Guillermina Ferro-Flores
- Laboratorio Nacional de Investigación y Desarrollo de Radiofármacos, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N. La Marquesa, Ocoyoacac 52750, Mexico; (G.F.-F.); (B.O.-G.)
| | - Sofia Turato
- Istituto Oncologico Veneto IOV-IRCCS, Via Gattamelata 64, 35138 Padova, Italy; (S.T.); (A.R.)
| | - Blanca Ocampo-Garcia
- Laboratorio Nacional de Investigación y Desarrollo de Radiofármacos, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N. La Marquesa, Ocoyoacac 52750, Mexico; (G.F.-F.); (B.O.-G.)
| | - Debora Carpanese
- Istituto Oncologico Veneto IOV-IRCCS, Via Gattamelata 64, 35138 Padova, Italy; (S.T.); (A.R.)
| | - Cristina Marzano
- Dipartimento di Scienze del Farmaco, Università degli Studi di Padova, Via Marzolo 5, 35131 Padova, Italy; (C.M.); (B.S.)
| | - Barbara Spolaore
- Dipartimento di Scienze del Farmaco, Università degli Studi di Padova, Via Marzolo 5, 35131 Padova, Italy; (C.M.); (B.S.)
| | - Giulio Fracasso
- Dipartimento di Scienze Biomediche, Università degli Studi di Padova, Viale G. Colombo 3, 35131 Padova, Italy
| | - Antonio Rosato
- Istituto Oncologico Veneto IOV-IRCCS, Via Gattamelata 64, 35138 Padova, Italy; (S.T.); (A.R.)
- Dipartimento di Scienze Chirurgiche Oncologiche e Gastroenterologiche, Università degli Studi di Padova, Via Gattamelata 64, 35138 Padova, Italy
| | - Laura Meléndez-Alafort
- Istituto Oncologico Veneto IOV-IRCCS, Via Gattamelata 64, 35138 Padova, Italy; (S.T.); (A.R.)
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Alati S, Singh R, Pomper MG, Rowe SP, Banerjee SR. Preclinical Development in Radiopharmaceutical Therapy for Prostate Cancer. Semin Nucl Med 2023; 53:663-686. [PMID: 37468417 DOI: 10.1053/j.semnuclmed.2023.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023]
Abstract
Prostate cancer is a leading cause of cancer death in men worldwide. Among the various treatment options, radiopharmaceutical therapy has shown notable success in metastatic, castration-resistant disease. Radiopharmaceutical therapy is a systemic approach that delivers cytotoxic radiation doses precisely to the malignant tumors and/or tumor microenvironment. Therapeutic radiopharmaceuticals are composed of a therapeutic radionuclide and a high-affinity, tumor-targeting carrier molecule. Therapeutic radionuclides used in preclinical prostate cancer studies are primarily α-, β--, or Auger-electron-emitting radiometals or radiohalogens. Monoclonal antibodies, antibody-derived fragments, peptides, and small molecules are frequently used as tumor-targeting molecules. Over the years, several important membrane-associated proteases and receptors have been identified, validated, and subsequently used for preclinical radiotherapeutic development for prostate cancer. Prostate-specific membrane antigen (PSMA) is the most well-studied prostate cancer-associated protease in preclinical literature. PSMA-targeting radiotherapeutic agents are being investigated using high-affinity antibody- and small-molecule-based agents for safety and efficacy. Early generations of such agents were developed simply by replacing radionuclides of the imaging agents with therapeutic ones. Later, extensive structure-activity relationship studies were conducted to address the safety and efficacy issues obtained from initial patient data. Recent regulatory approval of the 177Lu-labeled low-molecular-weight agent, 177Lu-PSMA-617, is a significant accomplishment. Current preclinical experiments are focused on the structural modification of 177Lu-PSMA-617 and relevant investigational agents to increase tumor targeting and reduce off-target binding and toxicity in healthy organs. While lutetium-177 (177Lu) remains the most widely used radionuclide, radiolabeled analogs with iodine-131 (128I), yttrium-90 (89Y), copper-67 (67Cu), and terbium-161 (161Tb) have been evaluated as potential alternatives in recent years. In addition, agents carrying the α-particle-emitting radiohalogen, astatine-211 (211At), or radiometals, actinium-225 (225Ac), lead-212 (212Pb), radium-223 (223Ra), and thorium-227 (227Th), have been increasingly investigated in preclinical research. Besides PSMA-based radiotherapeutics, other prominent prostate cancer-related proteases, for example, human kallikrein peptidases (HK2 and HK3), have been explored using monoclonal-antibody-(mAb)-based targeting platforms. Several promising mAbs targeting receptors overexpressed on the different stages of prostate cancer have also been developed for radiopharmaceutical therapy, for example, Delta-like ligand 3 (DLL-3), CD46, and CUB domain-containing protein 1 (CDCP1). Progress is also being made using peptide-based targeting platforms for the gastrin-releasing peptide receptor (GRPR), a well-established membrane-associated receptor expressed in localized and metastatic prostate cancers. Furthermore, mechanism-driven combination therapies appear to be a burgeoning area in the context of preclinical prostate cancer radiotherapeutics. Here, we review the current developments related to the preclinical radiopharmaceutical therapy of prostate cancer. These are summarized in two major topics: (1) therapeutic radionuclides and (2) tumor-targeting approaches using monoclonal antibodies, small molecules, and peptides.
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Affiliation(s)
- Suresh Alati
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Rajan Singh
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Martin G Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Steven P Rowe
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD
| | - Sangeeta Ray Banerjee
- Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD; Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD.
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Melendez-Alafort L, Ferro-Flores G, De Nardo L, Ocampo-García B, Bolzati C. Zirconium immune-complexes for PET molecular imaging: Current status and prospects. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.215005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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5
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Keot N, Sarma M. Computational insight into a mechanistic overview of water exchange kinetics and thermodynamic stabilities of bis and tris-aquated complexes of lanthanides. RSC Adv 2023; 13:1516-1529. [PMID: 36688060 PMCID: PMC9816859 DOI: 10.1039/d2ra05810c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/08/2022] [Indexed: 01/09/2023] Open
Abstract
A thorough investigation of Ln3+ complexes with more than one inner-sphere water molecule is crucial for designing high relaxivity contrast agents (CAs) used in magnetic resonance imaging (MRI). This study accomplished a comparative stability analysis of two hexadentate (H3cbda and H3dpaa) and two heptadentate (H4peada and H3tpaa) ligands with Ln3+ ions. The higher stability of the hexadentate H3cbda and heptadentate H4peada ligands has been confirmed by the binding affinity and Gibbs free energy analysis in aqueous solution. In addition, energy decomposition analysis (EDA) reveals the higher binding affinity of the peada4- ligand than the cbda3- ligand towards Ln3+ ions due to the higher charge density of the peada4- ligand. Moreover, a mechanistic overview of water exchange kinetics has been carried out based on the strength of the metal-water bond. The strength of the metal-water bond follows the trend Gd-O47 (w) > Gd-O39 (w) > Gd-O36 (w) in the case of the tris-aquated [Gd(cbda)(H2O)3] and Gd-O43 (w) > Gd-O40 (w) for the bis-aquated [Gd(peada)(H2O)2]- complex, which was confirmed by bond length, electron density (ρ), and electron localization function (ELF) at the corresponding bond critical points. Our analysis also predicts that the activation energy barrier decreases with the decrease in bond strength; hence k ex increases. The 17O and 1H hyperfine coupling constant values of all the coordinated water molecules were different, calculated by using the second-order Douglas-Kroll-Hess (DKH2) approach. Furthermore, the ionic nature of the bonding in the metal-ligand (M-L) bond was confirmed by the Quantum Theory of Atoms-In-Molecules (QTAIM) and ELF along with energy decomposition analysis (EDA). We hope that the results can be used as a basis for the design of highly efficient Gd(iii)-based high relaxivity MRI contrast agents for medical applications.
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Affiliation(s)
- Niharika Keot
- Department of Chemistry, Indian Institute of Technology GuwahatiAssam781039India+91 361 2582318
| | - Manabendra Sarma
- Department of Chemistry, Indian Institute of Technology GuwahatiAssam781039India+91 361 2582318
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Brunello S, Salvarese N, Carpanese D, Gobbi C, Melendez-Alafort L, Bolzati C. A Review on the Current State and Future Perspectives of [ 99mTc]Tc-Housed PSMA-i in Prostate Cancer. Molecules 2022; 27:molecules27092617. [PMID: 35565970 PMCID: PMC9099988 DOI: 10.3390/molecules27092617] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/12/2022] [Accepted: 04/12/2022] [Indexed: 02/01/2023] Open
Abstract
Recently, prostate-specific membrane antigen (PSMA) has gained momentum in tumor nuclear molecular imaging as an excellent target for both the diagnosis and therapy of prostate cancer. Since 2008, after years of preclinical research efforts, a plentitude of radiolabeled compounds mainly based on low molecular weight PSMA inhibitors (PSMA-i) have been described for imaging and theranostic applications, and some of them have been transferred to the clinic. Most of these compounds include radiometals (e.g., 68Ga, 64Cu, 177Lu) for positron emission tomography (PET) imaging or endoradiotherapy. Nowadays, although the development of new PET tracers has caused a significant drop in single-photon emission tomography (SPECT) research programs and the development of new technetium-99m (99mTc) tracers is rare, this radionuclide remains the best atom for SPECT imaging owing to its ideal physical decay properties, convenient availability, and rich and versatile coordination chemistry. Indeed, 99mTc still plays a relevant role in diagnostic nuclear medicine, as the number of clinical examinations based on 99mTc outscores that of PET agents and 99mTc-PSMA SPECT/CT may be a cost-effective alternative for 68Ga-PSMA PET/CT. This review aims to give an overview of the specific features of the developed [99mTc]Tc-tagged PSMA agents with particular attention to [99mTc]Tc-PSMA-i. The chemical and pharmacological properties of the latter will be compared and discussed, highlighting the pros and cons with respect to [68Ga]Ga-PSMA11.
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Affiliation(s)
- Sara Brunello
- Institute of Condensed Matter Chemistry and Technologies for Energy ICMATE-CNR, Corso Stati Uniti 4, 35127 Padova, Italy; (S.B.); (N.S.)
| | - Nicola Salvarese
- Institute of Condensed Matter Chemistry and Technologies for Energy ICMATE-CNR, Corso Stati Uniti 4, 35127 Padova, Italy; (S.B.); (N.S.)
| | - Debora Carpanese
- Immunology and Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, Via Gattamelata 64, 35124 Padova, Italy;
| | - Carolina Gobbi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Marzolo 5, 35131 Padova, Italy;
| | - Laura Melendez-Alafort
- Immunology and Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, Via Gattamelata 64, 35124 Padova, Italy;
- Correspondence: (L.M.-A.); (C.B.)
| | - Cristina Bolzati
- Institute of Condensed Matter Chemistry and Technologies for Energy ICMATE-CNR, Corso Stati Uniti 4, 35127 Padova, Italy; (S.B.); (N.S.)
- Correspondence: (L.M.-A.); (C.B.)
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Validity of Anti-PSMA ScFvD2B as a Theranostic Tool: A Narrative-Focused Review. Biomedicines 2021; 9:biomedicines9121870. [PMID: 34944686 PMCID: PMC8698710 DOI: 10.3390/biomedicines9121870] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 11/17/2022] Open
Abstract
Prostate cancer (PCa) is the second leading cause of cancer among men, and its diagnosis and adequate staging are fundamental. Among the biomarkers identified in recent years for PCa management, prostate-specific-membrane-antigen (PSMA), physiologically expressed at a low level on healthy prostate and in other normal tissues and highly overexpressed in PCa, represents a reliable marker ideal for imaging and therapy. The development of anti-PSMA antibodies, such as D2B, demonstrated slow clearance of intact antibodies compared with fragments resulting in low tumor-to-blood ratios; however, the modular structural and functional nature of antibodies allowed the generation of smaller fragments, such as scFvs. In this review of the anti-PSMA antibody fragment scFvD2B, we combined further characterization of its biomolecular and tissue cross-reactivity characteristics with a comprehensive summary of what has already been performed in preclinical models to evaluate imaging and therapeutic activities. A molecular dynamics study was performed, and ScFvD2B occupied a limited conformational space, characterized by low-energy conformational basins, confirming the high stability of the protein structure. In the cross-reactivity study, the weak/absent immunoreactivity in non-tumor tissues was comparable to the PSMA expression reported in the literature. Biodistribution studies and therapeutic treatments were conducted in different animal models obtained by subcutaneous or locoregional injection of PSMA-positive-versus-negative xenografts. The maximum tumor uptake was observed for 123I(SPECT), 124I(PET), and optical imaging, which avoids kidney accumulation (compared with radiometals) and leads to an optimal tumor-to-kidney and tumor-to-background ratios. Regarding its possible use in therapy, experimental data suggested a strong and specific antitumor activity, in vitro and in vivo, obtained using CAR-T or NK-92/CAR cells expressing scFvD2B. Based on presented/reviewed data, we consider that scFvD2B, due to its versatility and robustness, seems to: (i) overcome some problems observed in other studied scFvs, very often relatively unstable and prone to form aggregates; (ii) have sufficient tumor-to-background ratios for targeting and imaging PSMA-expressing cancer; (iii) significantly redirect immune killing cells to PSMA-positive tumors when inserted in second-generation CAR-T or NK-92/CAR cells. These data suggest that our product can be considered the right reagent to fill the gap that still exists in PCa diagnosis and treatment.
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Cassells I, Ahenkorah S, Burgoyne AR, Van de Voorde M, Deroose CM, Cardinaels T, Bormans G, Ooms M, Cleeren F. Radiolabeling of Human Serum Albumin With Terbium-161 Using Mild Conditions and Evaluation of in vivo Stability. Front Med (Lausanne) 2021; 8:675122. [PMID: 34504849 PMCID: PMC8422959 DOI: 10.3389/fmed.2021.675122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/26/2021] [Indexed: 02/04/2023] Open
Abstract
Targeted radionuclide therapy (TRNT) is a promising approach for cancer therapy. Terbium has four medically interesting isotopes (149Tb, 152Tb, 155Tb and 161Tb) which span the entire radiopharmaceutical space (TRNT, PET and SPECT imaging). Since the same element is used, accessing the various diagnostic or therapeutic properties without changing radiochemical procedures and pharmacokinetic properties is advantageous. The use of (heat-sensitive) biomolecules as vector molecule with high affinity and selectivity for a certain molecular target is promising. However, mild radiolabeling conditions are required to prevent thermal degradation of the biomolecule. Herein, we report the evaluation of potential bifunctional chelators for Tb-labeling of heat-sensitive biomolecules using human serum albumin (HSA) to assess the in vivo stability of the constructs. p-SCN-Bn-CHX-A”-DTPA, p-SCN-Bn-DOTA, p-NCS-Bz-DOTA-GA and p-SCN-3p-C-NETA were conjugated to HSA via a lysine coupling method. All HSA-constructs were labeled with [161Tb]TbCl3 at 40°C with radiochemical yields higher than 98%. The radiolabeled constructs were stable in human serum up to 24 h at 37°C. 161Tb-HSA-constructs were injected in mice to evaluate their in vivo stability. Increasing bone accumulation as a function of time was observed for [161Tb]TbCl3 and [161Tb]Tb-DTPA-CHX-A”-Bn-HSA, while negligible bone uptake was observed with the DOTA, DOTA-GA and NETA variants over a 7-day period. The results indicate that the p-SCN-Bn-DOTA, p-NCS-Bz-DOTA-GA and p-SCN-3p-C-NETA are suitable bifunctional ligands for Tb-based radiopharmaceuticals, allowing for high yield radiolabeling in mild conditions.
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Affiliation(s)
- Irwin Cassells
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, KU Leuven, Leuven, Belgium.,Belgian Nuclear Research Centre (SCK CEN), Institute for Nuclear Materials Science, Mol, Belgium
| | - Stephen Ahenkorah
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, KU Leuven, Leuven, Belgium.,Belgian Nuclear Research Centre (SCK CEN), Institute for Nuclear Materials Science, Mol, Belgium
| | - Andrew R Burgoyne
- Belgian Nuclear Research Centre (SCK CEN), Institute for Nuclear Materials Science, Mol, Belgium
| | - Michiel Van de Voorde
- Belgian Nuclear Research Centre (SCK CEN), Institute for Nuclear Materials Science, Mol, Belgium
| | - Christophe M Deroose
- Nuclear Medicine, University Hospitals Leuven, Nuclear Medicine & Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Thomas Cardinaels
- Belgian Nuclear Research Centre (SCK CEN), Institute for Nuclear Materials Science, Mol, Belgium.,Department of Chemistry, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, KU Leuven, Leuven, Belgium
| | - Maarten Ooms
- Belgian Nuclear Research Centre (SCK CEN), Institute for Nuclear Materials Science, Mol, Belgium
| | - Frederik Cleeren
- Radiopharmaceutical Research, Department of Pharmacy and Pharmacology, KU Leuven, Leuven, Belgium
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Chakraborty A, Mitra A, Tawate M, Sahoo S, Lad S, Rakshit S, Gaikwad S, Basu S, Shimpi H, Banerjee S. Therapeutic Multidose Preparation of a Ready-to-Use 177Lu-PSMA-617 Using Carrier Added Lutetium-177 in a Hospital Radiopharmacy and Its Clinical Efficacy. Cancer Biother Radiopharm 2021; 36:682-692. [PMID: 34402687 DOI: 10.1089/cbr.2020.4261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Introduction: [177Lu]Lu-prostate-specific membrane antigen (PSMA)-617 has emerged as a promising radiopharmaceutical for targeting PSMA in metastatic castrate-resistant prostate carcinoma (mCRPC). We have optimized the radiolabeling protocol for a multidose formulation (27-28.8 GBq equivalent to 6-7 patient-doses) of [177Lu]Lu-PSMA-617 using [177Lu]Lu3+ produced via 176Lu(n,γ)177Lu route with moderate specific activity (0.66-0.81 GBq/μg). Methods: [177Lu]Lu-PSMA-617 was synthesized using moderate specific activity [177Lu]LuCl3 (0.74 GBq/μg) with PSMA-617 having metal-to-ligand molar ratio ∼1: 2.5 in CH3COONH4 buffer (0.1 M) containing gentisic acid at pH 4.0-4.5. Human prostate carcinoma cell line LNCaP cell (high PSMA expression) was used for in vitro cell-binding studies and generating tumor xenograft models in nude mice for tissue biodistribution studies. Several batches of the present formulation have been clinically administered in mCRPC patients (single patient dose: 4.44-5.55 GBq per cycle). Results: In this study we report a consistent and reproducible protocol for multidose formulations of [177Lu]Lu-PSMA-617 for adopting in a hospital radiopharmacy setting. Although the radiochemical yield of [177Lu]Lu-PSMA-617 was found to be 97.30% ± 1.03%, the radiochemical purity was 98.24% ± 0.50% (n = 19). In vitro and serum stability of [177Lu]Lu-PSMA-617 was retained up to 72 and 120 h after radiolabeling and upon storage at -20°C with a radioactive concentration between 0.37 and 0.74 GBq/mL upon using stabilizer concentration as low as 43-48 μg/mCi. Preclinical cell-binding studies of [177Lu]Lu-PSMA-617 revealed specific binding with LNCaP cells of 17.4% ± 2.4%. The uptake in LnCaP xenografted tumor (nude mice) was 7.5 ± 2.6% ID/g for ∼1.5-2.0 cm3 tumor volume at 24-h post-injection. Post-therapy (24 h) SPECT image of mCRPC patients with prior orchidectomy and various hormone therapy showed specific localization of [177Lu]Lu-PSMA-617 in the tumor region. Conclusions: Formulation of a ready-to-use multidose formulation of [177Lu]Lu-PSMA-617 was successfully achieved and the procedure was optimized for routine preparation at a hospital radiopharmacy set-up. High degree of localization of [177Lu]Lu-PSMA-617 in post-therapy SPECT scan and the post-therapeutic response confirms its therapeutic efficacy. Clinical Trials.gov ID: RPC/51/Minutes/Final dated 16th October, 2019.
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Affiliation(s)
- Avik Chakraborty
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India.,Department of Atomic Energy, Homi Bhabha National Institute, Mumbai, India
| | - Arpit Mitra
- Medical Cyclotron Facility, Radiation Medicine Centre, Board of Radiation and Isotope Technology, Mumbai, India
| | - Megha Tawate
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India
| | - Sudip Sahoo
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India
| | - Sangita Lad
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India
| | - Sutapa Rakshit
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India
| | - Sujay Gaikwad
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India.,Department of Atomic Energy, Homi Bhabha National Institute, Mumbai, India
| | - Sandip Basu
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India.,Department of Atomic Energy, Homi Bhabha National Institute, Mumbai, India
| | - Hemant Shimpi
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India
| | - Sharmila Banerjee
- Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India.,Department of Atomic Energy, Homi Bhabha National Institute, Mumbai, India.,Medical Cyclotron Facility, Radiation Medicine Centre, Board of Radiation and Isotope Technology, Mumbai, India
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Meléndez-Alafort L, Ferro-Flores G, Santos-Cuevas C, Ocampo-García B, Turato S, Fracasso G, Bolzati C, Rosato A, De Nardo L. Preclinical dosimetric studies of 177 Lu-scFvD2B and comparison with 177 Lu-PSMA-617 and 177 Lu-iPSMA endoradiotherapeutic agents. Med Phys 2021; 48:4064-4074. [PMID: 33966284 DOI: 10.1002/mp.14936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 04/19/2021] [Accepted: 04/30/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Internal dosimetry has become a very important tool to evaluate the risks and benefits of new endoradiotherapeutic agents. Nowadays, some of the most successful targeted radionuclide therapy (TRT) agents are 177 Lu-DOTA conjugates based on low molecular weight (LMW) Glu-ureido PSMA inhibitors. It has, however, been demonstrated that the DOTA chelating moiety reduces the internalization of the LMW-PSMA agent and its radiation dose to the tumor. Previously, we reported that 177 Lu-scFvD2B, an antibody-based construct, demonstrated statistically significant higher cell uptake and internalization in LNCaP prostate cancer (PCa) cells (PSMA-positive) when compared to the LMW-PSMA agents, 177 Lu-PSMA-617 and 177 Lu-iPSMA, two of the endoradiotherapeutic agents which currently are the most used in PCa therapy. The aim of this study is to estimate the preclinical 177 Lu-scFvD2B organ and tumor-absorbed doses, and to compare the values with those of 177 Lu-PSMA-617 and 177 Lu-iPSMA. METHODS 177 Lu-scFvD2B, 177 Lu-PSMA-617, and 177 Lu-iPSMA were prepared and their radiochemical purity determined. Biodistribution studies of each radiopharmaceutical were then carried out in healthy mice to define the main source organs (SO) and to calculate the number of disintegrations in each source organs per unit of administered activity (NSO ). Absorbed dose in the main organs were then calculated for each 177 Lu-conjugate by means of OLINDA/EXM 2.1.1 software, using the calculated NSO for both the adult male and the mouse phantoms as program inputs. Images of mice bearing micropulmonary tumors injected with 177 Lu-conjugates were also obtained. Tumor standardized uptake values (SUV) for the different conjugates, obtained from the 3D SPECT image reconstruction of these mice, were used as the number of disintegrations in a tumor site per unit of administered activity (NT ). The tumor-absorbed dose was calculated using the published electron dose S-values for sphere models with diameters ranging from 10 µm to 10 mm and considering a uniform activity distribution and tumor density equivalent to water density. RESULTS All 177 Lu-labeled agents were obtained in high yield (98%). Dosimetric studies carried out using mouse phantoms demonstrated that organ absorbed doses of 177 Lu-scFvD2B were from 1.4 to 2.3 times higher than those for 177 Lu-iPSMA and from 1.5 to 2.6 times higher than those for 177 Lu-PSMA-617. However, the 177 Lu-scFvD2B values of tumor-absorbed doses for all investigated tumor sizes were from 2.8 to 3.0 times greater than those calculated for 177 Lu-iPSMA and 177 Lu-PSMA-617, respectively. Moreover, 177 Lu-scFvD2B showed the highest tumor/kidney ratio when compared to those reported for 177 Lu-albumin conjugates. CONCLUSIONS In this preclinical study, we demonstrated the potential of 177 Lu-scFvD2B as a therapeutic agent for PSMA-expressing tumors, due to its higher tumor-absorbed dose when compared with 177 Lu-LMW agents.
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Affiliation(s)
| | - Guillermina Ferro-Flores
- Laboratorio Nacional de Investigación y Desarrollo de Radiofármacos-CONACyT, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, La Marquesa, Ocoyoacac,, 52750, Estado de México, México
| | - Clara Santos-Cuevas
- Laboratorio Nacional de Investigación y Desarrollo de Radiofármacos-CONACyT, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, La Marquesa, Ocoyoacac,, 52750, Estado de México, México
| | - Blanca Ocampo-García
- Laboratorio Nacional de Investigación y Desarrollo de Radiofármacos-CONACyT, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca S/N, La Marquesa, Ocoyoacac,, 52750, Estado de México, México
| | - Sofia Turato
- Veneto Institute of Oncology IOV-IRCCS, Via Gattamelata 64, 35138, Padua, Italy
| | - Giulio Fracasso
- Department of Medicine, University of Verona, Piaz. Le L.A. Scuro 10, 37134, Verona, Italy
| | - Cristina Bolzati
- Institute of Condensed Matter Chemistry and Energy Technologies, ICMATE-CNR, Corso Stati Uniti 4, 35127, Padua, Italy
| | - Antonio Rosato
- Veneto Institute of Oncology IOV-IRCCS, Via Gattamelata 64, 35138, Padua, Italy.,Department of Surgery, Oncology and Gastroenterology, University of Padua, Via Gattamelata 64, 35138, Padua, Italy
| | - Laura De Nardo
- Department of Physics and Astronomy, University of Padua, Via Marzolo 8, 35131, Padua, Italy.,INFN, Sezione di Padova, Via Marzolo 8, 35131, Padua, Italy
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