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Zhang H, Qi L, Cai Y, Gao X. Gastrin-releasing peptide receptor (GRPR) as a novel biomarker and therapeutic target in prostate cancer. Ann Med 2024; 56:2320301. [PMID: 38442298 PMCID: PMC10916925 DOI: 10.1080/07853890.2024.2320301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 02/13/2024] [Indexed: 03/07/2024] Open
Abstract
Aim: This comprehensive review aims to explore the potential applications of Gastrin-releasing peptide receptor (GRPR) in the diagnosis and treatment of prostate cancer. Additionally, the study investigates the role of GRPR in prognostic assessment for individuals afflicted with prostate cancer.Methods: The review encompasses a thorough examination of existing literature and research studies related to the upregulation of GRPR in various tumor types, with a specific focus on prostate. The review also evaluates the utility of GRPR as a molecular target in prostate cancer research, comparing its significance to the well-established Prostate-specific membrane antigen (PSMA). The integration of radionuclide-targeted therapy with GRPR antagonists is explored as an innovative therapeutic approach for individuals with prostate cancer.Results: Research findings suggest that GRPR serves as a promising molecular target for visualizing low-grade prostate cancer. Furthermore, it is demonstrated to complement the detection of lesions that may be negative for PSMA. The integration of radionuclide-targeted therapy with GRPR antagonists presents a novel therapeutic paradigm, offering potential benefits for individuals undergoing treatment for prostate cancer.Conclusions: In conclusion, this review highlights the emerging role of GRPR in prostate cancer diagnosis and treatment. Moreover, the integration of radionuclide-targeted therapy with GRPR antagonists introduces an innovative therapeutic approach that holds promise for improving outcomes in individuals dealing with prostate cancer. The potential prognostic value of GRPR in assessing the disease's progression adds another dimension to its clinical significance in the realm of urology.
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Affiliation(s)
- Honghu Zhang
- Department of Urology, Disorders of Prostate Cancer Multidisciplinary Team, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha City, P. R. China
| | - Lin Qi
- Department of Urology, Disorders of Prostate Cancer Multidisciplinary Team, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha City, P. R. China
| | - Yi Cai
- Department of Urology, Disorders of Prostate Cancer Multidisciplinary Team, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha City, P. R. China
| | - Xiaomei Gao
- Department of Pathology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha City, P. R. China
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Wang L, Chen CC, Zhang Z, Kuo HT, Zhang C, Colpo N, Merkens H, Bénard F, Lin KS. Synthesis and Evaluation of Novel 68Ga-Labeled [D-Phe 6,Leu 13ψThz 14]bombesin(6-14) Analogs for Cancer Imaging with Positron Emission Tomography. Pharmaceuticals (Basel) 2024; 17:621. [PMID: 38794191 PMCID: PMC11124507 DOI: 10.3390/ph17050621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 05/05/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
Gastrin-releasing peptide receptor (GRPR) is overexpressed in various cancers and is a promising target for cancer diagnosis and therapy. However, the high pancreas uptake and/or metabolic instability observed for most reported GRPR-targeted radioligands might limit their clinical applications. Our group recently reported a GRPR-targeted antagonist tracer, [68Ga]Ga-TacsBOMB2 ([68Ga]Ga-DOTA-Pip-D-Phe6-Gln7-Trp8-Ala9-Val10-Gly11-His12-Leu13ψThz14-NH2), which showed a minimal pancreas uptake in a preclinical mouse model. In this study, we synthesized four derivatives with unnatural amino acid substitutions (Tle10-derived Ga-LW01158, NMe-His12-derived Ga-LW01160, α-Me-Trp8- and Tle10-derived Ga-LW01186, and Tle10- and N-Me-Gly11-derived Ga-LW02002) and evaluated their potential for detecting GRPR-expressing tumors with positron emission tomography (PET). The binding affinities (Ki(GRPR)) of Ga-LW01158, Ga-LW01160, Ga-LW01186, and Ga-LW02002 were 5.11 ± 0.47, 187 ± 17.8, 6.94 ± 0.95, and 11.0 ± 0.39 nM, respectively. [68Ga]Ga-LW01158, [68Ga]Ga-LW01186, and [68Ga]Ga-LW02002 enabled clear visualization of subcutaneously implanted human prostate cancer PC-3 tumor xenografts in mice in PET images. Ex vivo biodistribution studies showed that [68Ga]Ga-LW01158 had the highest tumor uptake (11.2 ± 0.65 %ID/g) and good tumor-to-background uptake ratios at 1 h post-injection. Comparable in vivo stabilities were observed for [68Ga]Ga-LW01158, [68Ga]Ga-LW01186, and [68Ga]Ga-LW02002 (76.5-80.7% remaining intact in mouse plasma at 15 min post-injection). In summary, the Tle10 substitution, either alone or combined with α-Me-Trp8 or NMe-Gly11 substitution, in Ga-TacsBOMB2 generates derivatives that retained good GRPR binding affinity and in vivo stability. With good tumor uptake and tumor-to-background imaging contrast, [68Ga]Ga-LW01158 is promising for detecting GRPR-expressing lesions with PET.
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Affiliation(s)
- Lei Wang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
| | - Chao-Cheng Chen
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
| | - Zhengxing Zhang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
| | - Hsiou-Ting Kuo
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
| | - Chengcheng Zhang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
| | - Nadine Colpo
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
- Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC V5Z 4E6, Canada
| | - Helen Merkens
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
| | - François Bénard
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
- Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada; (L.W.); (C.-C.C.); (Z.Z.); (H.-T.K.); (C.Z.); (N.C.); (H.M.); (F.B.)
- Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
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Liu Y, Xia L, Li H, Cai P, Tang S, Feng Y, Liu G, Chen Y, Liu N, Zhang W, Zhou Z. Exploring the impact of PEGylation on pharmacokinetics: a size-dependent effect of polyethylene glycol on prostate-specific membrane antigen inhibitors. EJNMMI Res 2024; 14:15. [PMID: 38324095 PMCID: PMC10850047 DOI: 10.1186/s13550-024-01071-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 01/24/2024] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Prostate cancer is the second most frequent cancer and the fifth leading cause of cancer-related deaths in men. Prostate-specific membrane antigen (PSMA) as a target has gained increasing attention. This research aims to investigate and understand how altering size of PEG impacts the in vitro and in vivo behavior and performance of PSMA inhibitors, with a specific focus on their pharmacokinetic characteristics and targeting properties. RESULTS Two 68Ga-labeled PSMA-targeted radiotracers were developed, namely [68Ga]Ga-PP4-WD and [68Ga]Ga-PP8-WD, with varying sizes of polyethylene glycol (PEG). [68Ga]Ga-PP4-WD and [68Ga]Ga-PP8-WD had excellent affinity for PSMA with IC50 being 8.06 ± 0.91, 6.13 ± 0.79 nM, respectively. Both tracers enabled clear visualization of LNCaP tumors in PET images with excellent tumor-to-background contrast. They also revealed highly efficient uptake and internalization into LNCaP cells, increasing over time. The biodistribution studies demonstrated that both radioligands exhibited significant and specific uptake into LNCaP tumors. Furthermore, they were rapidly cleared through the renal pathway, as evidenced by [68Ga]Ga-PP4-WD and [68Ga]Ga-PP8-WD showing a tenfold and a fivefold less in renal uptake, respectively, compared to [68Ga]Ga-Flu-1 in 30 min. Both in vitro and in vivo experiments demonstrated that PEG size significantly impacted tumor-targeting and pharmacokinetic properties. CONCLUSIONS These radiotracers have demonstrated their effectiveness in significantly reducing kidney uptake while maintaining the absorbed dose in tumors. Both radiotracers exhibited strong binding and internalization characteristics in vitro, displayed high specificity and affinity for PSMA in vivo.
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Affiliation(s)
- Yang Liu
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Li Xia
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Haiyang Li
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Ping Cai
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Sufan Tang
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Yue Feng
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Guangfu Liu
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Yue Chen
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
| | - Nan Liu
- Department of Nuclear Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Sichuan, Chengdu, China.
| | - Wei Zhang
- Department of Nuclear Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Sichuan, Chengdu, China.
| | - Zhijun Zhou
- Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, The Affiliated Hospital, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
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Wang L, Kuo HT, Zhang Z, Zhang C, Chen CC, Chapple D, Wilson R, Colpo N, François Bénard, Lin KS. Unnatural amino acid substitutions to improve in vivo stability and tumor uptake of 68Ga-labeled GRPR-targeted TacBOMB2 derivatives for cancer imaging with positron emission tomography. EJNMMI Radiopharm Chem 2024; 9:8. [PMID: 38305955 PMCID: PMC10837402 DOI: 10.1186/s41181-024-00241-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/25/2024] [Indexed: 02/03/2024] Open
Abstract
BACKGROUND Overexpressed in various solid tumors, gastrin-releasing peptide receptor (GRPR) is a promising cancer imaging marker and therapeutic target. Although antagonists are preferable for the development of GRPR-targeted radiopharmaceuticals due to potentially fewer side effects, internalization of agonists may lead to longer tumor retention and better treatment efficacy. In this study, we systematically investigated unnatural amino acid substitutions to improve in vivo stability and tumor uptake of a previously reported GRPR-targeted agonist tracer, [68Ga]Ga-TacBOMB2 (68Ga-DOTA-Pip-D-Phe6-Gln7-Trp8-Ala9-Val10-Gly11-His12-Leu13-Thz14-NH2). RESULTS Unnatural amino acid substitutions were conducted for Gln7, Trp8, Ala9, Val10, Gly11 and His12, either alone or in combination. Out of 25 unnatural amino acid substitutions, tert-Leu10 (Tle10) and NMe-His12 substitutions were identified to be preferable modifications especially in combination. Compared with the previously reported [68Ga]Ga-TacBOMB2, the Tle10 and NMe-His12 derived [68Ga]Ga-LW01110 showed retained agonist characteristics and improved GRPR binding affinity (Ki = 7.62 vs 1.39 nM), in vivo stability (12.7 vs 89.0% intact tracer in mouse plasma at 15 min post-injection) and tumor uptake (5.95 vs 16.6 %ID/g at 1 h post-injection). CONCLUSIONS Unnatural amino acid substitution is an effective strategy to improve in vivo stability and tumor uptake of peptide-based radiopharmaceuticals. With excellent tumor uptake and tumor-to-background contrast, [68Ga]Ga-LW01110 is promising for detecting GRPR-expressing cancer lesions with PET. Since agonists can lead to internalization upon binding to receptors and foreseeable long tumor retention, our optimized GRPR-targeted sequence, [Tle10,NMe-His12,Thz14]Bombesin(7-14), is a promising template for use for the design of GRPR-targeted radiotherapeutic agents.
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Affiliation(s)
- Lei Wang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Hsiou-Ting Kuo
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Zhengxing Zhang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Chengcheng Zhang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Chao-Cheng Chen
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Devon Chapple
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Ryan Wilson
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Nadine Colpo
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
- Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC, V5Z4E6, Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
- Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC, V5Z4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, V5Z1M9, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada.
- Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC, V5Z4E6, Canada.
- Department of Radiology, University of British Columbia, Vancouver, BC, V5Z1M9, Canada.
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Verhoeven M, Haeck J, de Blois E, Orlandi F, Barbato D, Tedesco M, Konijnenberg M, Dalm SU. The Balance Between the Therapeutic Efficacy and Safety of [ 177Lu]Lu-NeoB in a Preclinical Prostate Cancer Model. Mol Imaging Biol 2024; 26:114-123. [PMID: 37640941 PMCID: PMC10828073 DOI: 10.1007/s11307-023-01851-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/11/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023]
Abstract
PURPOSE Radiolabeled NeoB is a promising gastrin-releasing peptide receptor (GRPR)-targeting radiopharmaceutical for theranostics of GRPR-expressing malignancies, e.g., prostate cancer (PCa). The aim of this study was to evaluate the effect of different doses of [177Lu]Lu-NeoB on the balance between therapeutic efficacy and safety in a preclinical PCa model. PROCEDURES To determine the efficacy of [177Lu]Lu-NeoB, PC-3 xenografted mice received 3 sham injections (control group) or 3 injections of 30 MBq/300 pmol, 40 MBq/400 pmol, or 60 MBq/600 pmol [177Lu]Lu-NeoB (groups 1, 2, and 3, respectively) 1 week apart. To quantify tumor uptake, single-photon emission computed tomography/computed tomography (SPECT/CT) imaging was performed 4 h after the first, second, and third injection on a separate group of animals. For safety evaluations, pancreatic and renal tissues of non-tumor-bearing mice treated with the abovementioned [177Lu]Lu-NeoB doses were evaluated 12 and 24 weeks post-treatment. RESULTS Treatment of PC-3 tumors with all three studied [177Lu]Lu-NeoB doses was effective. Median survival times were significantly (p < 0.0001) improved for treatment groups 1, 2, and 3 versus the control group (82 days, 89 days, 99 days versus 19 days, respectively). However, no significant differences were observed between treatment groups. Quantification of SPECT/CT images showed minimal differences in the average absolute radioactivity uptake, especially after the third injection. Histopathological analysis revealed no clear signs of treatment-related pancreatic toxicity. For the kidneys, atrophy and fibrosis were observed for one animal from group 1 and a chronic inflammatory response was observed for both animals from group 3 at 24 weeks post-treatment. CONCLUSIONS Treatment with [177Lu]Lu-NeoB is effective in a preclinical PCa model. Adjusting the administered dose could positively impact the risk-benefit balance as a higher dose might not lead to an increased therapeutic effect, but it may lead to an increase in toxicological effects in healthy organs such as the kidneys.
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Affiliation(s)
- Marjolein Verhoeven
- Department of Radiology & Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD, Rotterdam, The Netherlands
| | - Joost Haeck
- Department of Radiology & Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD, Rotterdam, The Netherlands
| | - Erik de Blois
- Department of Radiology & Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD, Rotterdam, The Netherlands
| | - Francesca Orlandi
- Advanced Accelerator Applications, a Novartis Company, 10010, Colleretto Giacosa, Italy
| | - Donato Barbato
- Advanced Accelerator Applications, a Novartis Company, 10010, Colleretto Giacosa, Italy
| | - Mattia Tedesco
- Advanced Accelerator Applications, a Novartis Company, 10010, Colleretto Giacosa, Italy
| | - Mark Konijnenberg
- Department of Radiology & Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD, Rotterdam, The Netherlands
| | - Simone U Dalm
- Department of Radiology & Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD, Rotterdam, The Netherlands.
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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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Abouzayed A, Kanellopoulos P, Gorislav A, Tolmachev V, Maina T, Nock BA, Orlova A. Preclinical Characterization of a Stabilized Gastrin-Releasing Peptide Receptor Antagonist for Targeted Cancer Theranostics. Biomolecules 2023; 13:1134. [PMID: 37509170 PMCID: PMC10377574 DOI: 10.3390/biom13071134] [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: 06/01/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Radiolabeled gastrin-releasing peptide receptor (GRPR) antagonists have shown great promise for the theranostics of prostate cancer; however, their suboptimal metabolic stability leaves room for improvements. It was recently shown that the replacement of Gly11 with Sar11 in the peptidic [D-Phe6,Leu13-NHEt,des-Met14]BBN(6-14) chain stabilized the [99mTc]Tc-DB15 radiotracer against neprilysin (NEP). We herein present DOTAGA-PEG2-(Sar11)RM26 (AU-RM26-M1), after Gly11 to Sar11-replacement. The impact of this replacement on the metabolic stability and overall biological performance of [111In]In-AU-RM26-M1 was studied using a head-to-head comparison with the unmodified reference [111In]In-DOTAGA-PEG2-RM26. In vitro, the cell uptake of [111In]In-AU-RM26-M1 could be significantly reduced in the presence of a high-excess GRPR-blocker that demonstrated its specificity. The cell uptake of both radiolabeled GRPR antagonists increased with time and was superior for [111In]In-AU-RM26-M1. The dissociation constant reflected strong affinities for GRPR (500 pM for [111In]In-AU-RM26-M1). [111In]In-AU-RM26-M1 showed significantly higher stability in peripheral mice blood at 5 min pi (88 ± 8% intact) than unmodified [111In]In-DOTAGA-PEG2-RM26 (69 ± 2% intact; p < 0.0001). The administration of a NEP inhibitor had no significant impact on the Sar11-compound (91 ± 2% intact; p > 0.05). In vivo, [111In]In-AU-RM26-M1 showed high and GRPR-mediated uptake in the PC-3 tumors (7.0 ± 0.7%IA/g vs. 0.9 ± 0.6%IA/g in blocked mice) and pancreas (2.2 ± 0.6%IA/g vs. 0.3 ± 0.2%IA/g in blocked mice) at 1 h pi, with rapid clearance from healthy tissues. The tumor uptake of [111In]In-AU-RM26-M1 was higher than for [111In]In-DOTAGA-PEG2-RM26 (at 4 h pi, 5.7 ± 1.8%IA/g vs. 3 ± 1%IA/g), concordant with its higher stability. The implanted PC-3 tumors were visualized with high contrast in mice using [111In]In-AU-RM26-M1 SPECT/CT. The Gly11 to Sar11-substitution stabilized [111In]In-DOTAGA-PEG2-(Sar11)RM26 against NEP without negatively affecting other important biological features. These results support the further evaluation of AU-RM26-M1 for prostate cancer theranostics after labeling with clinically relevant radionuclides.
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Affiliation(s)
- Ayman Abouzayed
- Department of Medicinal Chemistry, Uppsala University, 751 83 Uppsala, Sweden; (A.A.); (P.K.); (A.G.)
| | - Panagiotis Kanellopoulos
- Department of Medicinal Chemistry, Uppsala University, 751 83 Uppsala, Sweden; (A.A.); (P.K.); (A.G.)
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15310 Athens, Greece; (T.M.); (B.A.N.)
| | - Alisa Gorislav
- Department of Medicinal Chemistry, Uppsala University, 751 83 Uppsala, Sweden; (A.A.); (P.K.); (A.G.)
| | - Vladimir Tolmachev
- Department of Immunology, Genetics and Pathology, Uppsala University, 751 83 Uppsala, Sweden;
| | - Theodosia Maina
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15310 Athens, Greece; (T.M.); (B.A.N.)
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15310 Athens, Greece; (T.M.); (B.A.N.)
| | - Anna Orlova
- Department of Medicinal Chemistry, Uppsala University, 751 83 Uppsala, Sweden; (A.A.); (P.K.); (A.G.)
- Science for Life Laboratory, Uppsala University, 752 37 Uppsala, Sweden
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[ 99mTc]Tc-HYNIC-RM2: A potential SPECT probe targeting GRPR expression in prostate cancers. Nucl Med Biol 2023; 118-119:108331. [PMID: 36933456 DOI: 10.1016/j.nucmedbio.2023.108331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/13/2023] [Accepted: 02/22/2023] [Indexed: 03/11/2023]
Abstract
INTRODUCTION Elevated density of gastrin releasing peptide receptors (GRPR) in prostate cancer has led to exploration of several radiolabeled peptides for imaging and staging of the disease. The GRPR antagonist peptide RM2 has been successfully conjugated with several chelators and radiolabeled with gallium-68. The goal of this study was to synthesize a 99mTc-labeled probe and investigate its potential for SPECT imaging of prostate cancer. Towards this HYNIC-RM2 peptide conjugate was synthesized, radiolabeled with 99mTc and evaluated in GRPR-positive PC3 tumor xenografts. METHODS HYNIC-RM2 was manually synthesized by standard Fmoc solid phase strategy and radiolabeled with 99mTc. In vitro cell studies were performed in GRPR-positive human prostate carcinoma (PC3) cells. Metabolic stability studies of [99mTc]Tc-HYNIC-RM2 were performed in normal mice in the presence as well as absence of neutral endopeptidase (NEP) inhibitor, phosphoramidon (PA). Biodistribution and imaging studies of [99mTc]Tc-HYNIC-RM2 were performed in SCID mice bearing PC3-xenograft. RESULTS [99mTc]Tc-HYNIC-RM2 exhibited high binding affinity in low nanomolar range (Kd = 1.83 ± 0.31 nM). Metabolic stability studies in mice indicated that in the absence of PA, radiolabeled peptide was about 65 % intact in the blood at 15 min p.i., whereas proportion of intact radiolabeled peptide was enhanced to 90 % on co-administration of PA. Biodistribution studies in PC3 tumor bearing mice demonstrated high tumor uptake (8.02 ± 0.9%ID/g and 6.13 ± 0.44%ID/g at 1 h and 3 h p.i.). Co-administration of PA with the radiolabeled peptide resulted in further enhancement of tumor uptake (14.24 ± 0.76 % ID/g and 11.71 ± 0.59%ID/g at 1 h and 3 h p.i.). SPECT/CT images of [99mTc]Tc-HYNIC-RM2 could clearly visualize the tumor. Significant (p < 0.001) reduction in the tumor uptake with a co-injected blocking dose of unlabeled peptide ascertained the GRPR specificity of [99mTc]Tc-HYNIC-RM2. CONCLUSION Encouraging results obtained in biodistribution and imaging studies indicate the potential of [99mTc]Tc-HYNIC-RM2 for further exploration as GRPR targeting agent.
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68Ga-Labeled [Thz 14]Bombesin(7-14) Analogs: Promising GRPR-Targeting Agonist PET Tracers with Low Pancreas Uptake. Molecules 2023; 28:molecules28041977. [PMID: 36838968 PMCID: PMC9962964 DOI: 10.3390/molecules28041977] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
With overexpression in various cancers, the gastrin-releasing peptide receptor (GRPR) is a promising target for cancer imaging and therapy. However, the high pancreas uptake of reported GRPR-targeting radioligands limits their clinical application. Our goal was to develop 68Ga-labeled agonist tracers for detecting GRPR-expressing tumors with positron emission tomography (PET), and compare them with the clinically validated agonist PET tracer, [68Ga]Ga-AMBA. Ga-TacBOMB2, TacBOMB3, and TacBOMB4, derived from [Thz14]Bombesin(7-14), were confirmed to be GRPR agonists by a calcium mobilization study, and their binding affinities (Ki(GRPR)) were determined to be 7.62 ± 0.19, 6.02 ± 0.59, and 590 ± 36.5 nM, respectively, via in vitro competition binding assays. [68Ga]Ga-TacBOMB2, [68Ga]Ga-TacBOMB3, and [68Ga]Ga-AMBA clearly visualized PC-3 tumor xenografts in a PET imaging study. [68Ga]Ga-TacBOMB2 showed comparable tumor uptake but superior tumor-to-background contrast ratios when compared to [68Ga]Ga-AMBA. Moreover, [68Ga]Ga-TacBOMB2 and [68Ga]Ga-TacBOMB3 showed a much lower rate of uptake in the pancreas (1.30 ± 0.14 and 2.41 ± 0.72%ID/g, respectively) than [68Ga]Ga-AMBA (62.4 ± 4.26%ID/g). In conclusion, replacing Met14 in the GRPR-targeting sequence with Thz14 retains high GRPR-binding affinity and agonist properties. With good tumor uptake and tumor-to-background uptake ratios, [68Ga]Ga-TacBOMB2 is promising for detecting GRPR-expressing tumors. The much lower pancreas uptake of [68Ga]Ga-TacBOMB2 and [68Ga]Ga-TacBOMB3 suggests that [Thz14]Bombesin(7-14) is a promising targeting vector for the design of GRPR-targeting radiopharmaceuticals, especially for radioligand therapy application.
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Xia L, Liu Y, Cai P, Feng Y, Yuan H, Tang S, Wang YW, Liu N, Chen Y, Zhou Z. Halogen Replacement on the Lysine Side Chain of Lys-Urea-Glu-Based PSMA Inhibitors Leads to Significant Changes in Targeting Properties. Mol Imaging Biol 2023:10.1007/s11307-023-01804-x. [PMID: 36695967 DOI: 10.1007/s11307-023-01804-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 01/26/2023]
Abstract
PURPOSE Investigate the impact of various halogens on pharmacokinetics, biodistribution, and micro positron emission tomography/computed tomography (PET/CT) imaging of Glu-urea-Lys-based prostate-specific membrane antigen (PSMA) inhibitors. PROCEDURES Based on the modification of SC691, a small molecule inhibitor of PSMA previously developed by our group, we synthesized 68Ga-labeled compounds by modifying the lysine terminal amino with different halogenated phenyl substituents. After complete characterization, in vitro and in vivo properties were studied. RESULTS The [68Ga]Ga-DOTA-SC691-R possesses a high radiochemical yield (98-99%). The internalization values of [68Ga]Ga-DOTA-SC691-H, [68Ga]Ga-DOTA-SC691-Cl, and [68Ga]Ga-DOTA-SC691-Br in LNCaP cells all displayed time-dependent pattern enhanced with time. The results of in vitro competitive inhibition assay showed that the affinity of natGa-DOTA-SC691-R for PSMA had a trend of H < F < Cl < Br < I. The blocking imaging and dynamic imaging on micro-PET/CT of male non-obese diabetic/severe combined immunodeficiency mice with LNCaP tumors showed the rapid tumor targeting properties of [68Ga]Ga-DOTA-SC691-R with specificity for PSMA. Static imaging of micro-PEC/CT of these compounds could rapidly localize LNCaP tumors with decent image quality (except for [68Ga]Ga-DOTA-SC691-H). Biodistribution data showed that [68Ga]Ga-DOTA-SC691-R were metabolized via the kidney and tumor accumulation followed the order of H ≈ F ≈ Cl < I < Br uptake values at 1 h. [68Ga]Ga-DOTA-SC691-Br showed the highest tumor accumulation and retention (15.21 ± 5.57%ID/g at 30 min, 20.39 ± 4.38%ID/g at 60 min, and 13.30 ± 4.39%ID/g at 120 min), which is consistent with the results of the competitive inhibition assay and cell binding assay. CONCLUSIONS It was demonstrated that the halogen substituent on the lysine terminal amino group on the Glu-urea-Lys backbone did positively affect the binding of [68Ga]Ga-DOTA-SC691-R to PSMA. The bulkier and less electronegative Br (or I) elements are preferred for structural modifications here.
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Affiliation(s)
- Li Xia
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Yang Liu
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Ping Cai
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Yue Feng
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Hongmei Yuan
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Sufan Tang
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Yin Wen Wang
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China
| | - Nan Liu
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Department of Nuclear Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Sichuan, Chengdu, China.
| | - Yue Chen
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China.
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
| | - Zhijun Zhou
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Jiangyang District, Luzhou, Sichuan, China.
- Institute of Nuclear Medicine, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
- Department of Pharmaceutics, School of Pharmacy, Southwest Medical University, Jiangyang District, Luzhou, Sichuan, China.
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Günther T, Konrad M, Stopper L, Kunert JP, Fischer S, Beck R, Casini A, Wester HJ. Optimization of the Pharmacokinetic Profile of [ 99mTc]Tc-N 4-Bombesin Derivatives by Modification of the Pharmacophoric Gln-Trp Sequence. Pharmaceuticals (Basel) 2022; 15:ph15091133. [PMID: 36145354 PMCID: PMC9500665 DOI: 10.3390/ph15091133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/06/2022] [Accepted: 09/06/2022] [Indexed: 11/16/2022] Open
Abstract
Current radiolabeled gastrin-releasing peptide receptor (GRPR) ligands usually suffer from high accumulation in GRPR-positive organs (pancreas, stomach), limiting tumor-to-background contrast in the abdomen. In novel N4-bombesin derivatives this was addressed by substitutions at the Gln7-Trp8 site within the MJ9 peptide (H-Pip5-phe6-Gln7-Trp8-Ala9-Val10-Gly11-His12-Sta13-Leu14-NH2) either by homoserine (Hse7), β-(3-benzothienyl) alanine (Bta8) or α-methyl tryptophan (α-Me-Trp8), with the aim of optimizing pharmacokinetics. We prepared and characterized the peptide conjugates 6-carboxy-1,4,8,11-tetraazaundecane (N4)-asp-MJ9, N4-asp-[Bta8]MJ9, N4-[Hse7]MJ9 and N4-[α-Me-Trp8]MJ9, and evaluated these compounds in vitro (GRPR affinity via IC50,inverse; internalization; lipophilicity via logD7.4) and in vivo (biodistribution and μSPECT/CT studies at 1 h post injection (p.i.) in PC-3 tumor-bearing CB17-SCID mice). 99mTc-labeling resulted in radiochemical yields (RCYs) > 95%. All 99mTc-labeled MJ9 analogues showed comparable or higher GRPR affinity than the external reference [99mTc]Tc-Demobesin 4. Receptor-bound fractions were noticeably higher than that of the reference. Despite a slightly enhanced lipophilicity, all novel MJ9 derivatives revealed improved in vivo pharmacokinetics compared to the reference. The Bta8-modified ligand revealed the most favorable tumor-to-abdomen contrast at 1 h p.i. Substitutions at the Gln7-Trp8 site within GRPR ligands hold great potential to modify pharmacokinetics for improved imaging.
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Kurth J, Potratz M, Heuschkel M, Krause BJ, Schwarzenböck SM. GRPr Theranostics: Current Status of Imaging and Therapy using GRPr Targeting Radiopharmaceuticals. Nuklearmedizin 2022; 61:247-261. [PMID: 35668669 DOI: 10.1055/a-1759-4189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Addressing molecular targets, that are overexpressed by various tumor entities, using radiolabeled molecules for a combined diagnostic and therapeutic (theranostic) approach is of increasing interest in oncology. The gastrin-releasing peptide receptor (GRPr), which is part of the bombesin family, has shown to be overexpressed in a variety of tumors, therefore, serving as a promising target for those theranostic applications. A large amount of differently radiolabeled bombesin derivatives addressing the GRPr have been evaluated in the preclinical as well as clinical setting showing fast blood clearance and urinary excretion with selective GRPr-binding. Most of the available studies on GRPr-targeted imaging and therapy have evaluated the theranostic approach in prostate and breast cancer applying bombesin derivatives tagged with the predominantly used theranostic pair of 68Ga/177Lu which is the focus of this review.
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Affiliation(s)
- Jens Kurth
- Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany
| | - Madlin Potratz
- Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany
| | - Martin Heuschkel
- Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany
| | - Bernd J Krause
- Department of Nuclear Medicine, Rostock University Medical Center, Rostock, Germany
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Maina T, Nock BA. Peptide radiopharmaceuticals for targeted diagnosis & therapy of human tumors. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00078-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Mansi R, Nock BA, Dalm SU, Busstra MB, van Weerden WM, Maina T. Radiolabeled Bombesin Analogs. Cancers (Basel) 2021; 13:cancers13225766. [PMID: 34830920 PMCID: PMC8616220 DOI: 10.3390/cancers13225766] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/13/2021] [Accepted: 11/15/2021] [Indexed: 12/16/2022] Open
Abstract
Simple Summary Recent medical advancements have strived for a personalized medicine approach to patients, aimed at optimizing therapy outcomes with minimum toxicity. In this respect, nuclear medicine methodologies have been playing increasingly important roles. For example, the overexpression of peptide receptors, such as the gastrin-releasing peptide receptor (GRPR), on tumor cells as opposed to their lack of expression in healthy surrounding tissues can be elegantly exploited with the aid of “smart” peptide carriers, such as the analogs of the amphibian 14-peptide bombesin (BBN). These molecules can bring clinically attractive radionuclides to malignant lesions in prostate, breast, and other human cancers, sparing healthy tissues. Depending upon the radionuclide in question, diagnostic imaging with single-photon emission computed tomography (SPECT) or positron emission tomography (PET) has been pursued, identifying patients who are eligible for peptide radionuclide receptor therapy (PRRT) in an integrated “theranostic” approach. In the present review, we (i) discuss the major steps taken in the development of anti-GRPR theranostic radioligands, with a focus on those selected for clinical testing; (ii) comment on the present status in this field of research; and (iii) reflect on the current limitations as well as on new opportunities for their broader and more successful clinical applications. Abstract The gastrin-releasing peptide receptor (GRPR) is expressed in high numbers in a variety of human tumors, including the frequently occurring prostate and breast cancers, and therefore provides the rationale for directing diagnostic or therapeutic radionuclides on cancer lesions after administration of anti-GRPR peptide analogs. This concept has been initially explored with analogs of the frog 14-peptide bombesin, suitably modified at the N-terminus with a number of radiometal chelates. Radiotracers that were selected for clinical testing revealed inherent problems associated with these GRPR agonists, related to low metabolic stability, unfavorable abdominal accumulation, and adverse effects. A shift toward GRPR antagonists soon followed, with safer analogs becoming available, whereby, metabolic stability and background clearance issues were gradually improved. Clinical testing of three main major antagonist types led to promising outcomes, but at the same time brought to light several limitations of this concept, partly related to the variation of GRPR expression levels across cancer types, stages, previous treatments, and other factors. Currently, these parameters are being rigorously addressed by cell biologists, chemists, nuclear medicine physicians, and other discipline practitioners in a common effort to make available more effective and safe state-of-the-art molecular tools to combat GRPR-positive tumors. In the present review, we present the background, current status, and future perspectives of this endeavor.
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Affiliation(s)
- Rosalba Mansi
- Division of Radiopharmaceutical Chemistry, Clinic of Radiology and Nuclear Medicine University Hospital Basel, 4031 Basel, Switzerland;
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15310 Athens, Greece;
| | - Simone U. Dalm
- Erasmus Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (S.U.D.); (M.B.B.); (W.M.v.W.)
| | - Martijn B. Busstra
- Erasmus Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (S.U.D.); (M.B.B.); (W.M.v.W.)
| | - Wytske M. van Weerden
- Erasmus Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (S.U.D.); (M.B.B.); (W.M.v.W.)
| | - Theodosia Maina
- Molecular Radiopharmacy, INRaSTES, NCSR “Demokritos”, 15310 Athens, Greece;
- Correspondence: ; Tel.: +30-650-3908/3891
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[ 99mTc]Tc-DB15 in GRPR-Targeted Tumor Imaging with SPECT: From Preclinical Evaluation to the First Clinical Outcomes. Cancers (Basel) 2021; 13:cancers13205093. [PMID: 34680243 PMCID: PMC8533986 DOI: 10.3390/cancers13205093] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 12/15/2022] Open
Abstract
Diagnostic imaging and radionuclide therapy of prostate (PC) and breast cancer (BC) using radiolabeled gastrin-releasing peptide receptor (GRPR)-antagonists represents a promising approach. We herein propose the GRPR-antagonist based radiotracer [99mTc]Tc-DB15 ([99mTc]Tc-N4-AMA-DGA-DPhe6,Sar11,LeuNHEt13]BBN(6-13); N4: 6-carboxy-1,4,8,11-tetraazaundecane, AMA: aminomethyl-aniline, DGA: diglycolic acid) as a new diagnostic tool for GRPR-positive tumors applying SPECT/CT. The uptake of [99mTc]Tc-DB15 was tested in vitro in mammary (T-47D) and prostate cancer (PC-3) cells and in vivo in T-47D or PC-3 xenograft-bearing mice as well as in BC patients. DB15 showed high GRPR-affinity (IC50 = 0.37 ± 0.03 nM) and [99mTc]Tc-DB15 strongly bound to the cell-membrane of T-47D and PC-3 cells, according to a radiolabeled antagonist profile. In mice, the radiotracer showed high and prolonged GRPR-specific uptake in PC-3 (e.g., 25.56 ± 2.78 %IA/g vs. 0.72 ± 0.12 %IA/g in block; 4 h pi) and T-47D (e.g., 15.82 ± 3.20 %IA/g vs. 3.82 ± 0.30 %IA/g in block; 4 h pi) tumors, while rapidly clearing from background. In patients with advanced BC, the tracer could reveal several bone and soft tissue metastases on SPECT/CT. The attractive pharmacokinetic profile of [99mTc]DB15 in mice and its capability to target GRPR-positive BC lesions in patients highlight its prospects for a broader clinical use, an option currently being explored by ongoing clinical studies.
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Pretze M, Reffert L, Diehl S, Schönberg SO, Wängler C, Hohenberger P, Wängler B. GMP-compliant production of [ 68Ga]Ga-NeoB for positron emission tomography imaging of patients with gastrointestinal stromal tumor. EJNMMI Radiopharm Chem 2021; 6:22. [PMID: 34228236 PMCID: PMC8260665 DOI: 10.1186/s41181-021-00137-w] [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: 04/26/2021] [Accepted: 06/09/2021] [Indexed: 12/15/2022] Open
Abstract
Background [68Ga]Ga-NeoB is a novel DOTA-coupled Gastrin Releasing Peptide Receptor (GRPR) antagonist with high affinity for GRPR and good in vivo stability. This study aimed at (1) the translation of preclinical results to the clinics and establish the preparation of [68Ga]Ga-NeoB using a GMP conform kit approach and a licensed 68Ge/68Ga generator and (2) to explore the application of [68Ga]Ga-NeoB in patients with gastrointestinal stromal tumors (GIST) before and/or after interventional treatment (selective internal radiotherapy, irreversible electroporation, microwave ablation). Results Validation of the production and quality control of [68Ga]Ga-NeoB for patient use had to be performed before starting the GMP production. Six independent batches of [68Ga]Ga-NeoB were produced, all met the quality and sterility criteria and yielded 712 ± 73 MBq of the radiotracer in a radiochemical purity of > 95% and a molar activity of 14.2 ± 1.5 GBq/μmol within 20 min synthesis time and additional 20 min quality control. Three patients (2 females, 1 male, 51–77 yrs. of age) with progressive gastrointestinal stromal tumor metastases in the liver or peritoneum not responsive to standard tyrosine kinase inhibitor therapy underwent both [68Ga]Ga-NeoB scans prior and after interventional therapy. Radiosynthesis of 68Ga-NeoB was performed using a kit approach under GMP conditions. No specific patient preparation such as fasting or hydration was required for [68Ga]Ga-NeoB PET/CT imaging. Contrast-enhanced PET/CT studies were performed. A delayed, second abdominal image after the administration of the of [68Ga]Ga-NeoB was acquired at 120 min post injection. Conclusions A fully GMP compliant kit preparation of [68Ga]Ga-NeoB enabling the routine production of the tracer under GMP conditions was established for clinical routine PET/CT imaging of patients with metastatic GIST and proved to adequately visualize tumor deposits in the abdomen expressing GRPR. Patients could benefit from additional information derived from [68Ga]Ga-NeoB diagnosis to assess the presence of GRPR in the tumor tissue and monitor antitumor treatment. Supplementary Information The online version contains supplementary material available at 10.1186/s41181-021-00137-w.
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Affiliation(s)
- Marc Pretze
- Department of Nuclear Medicine, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany. .,Molecular Imaging and Radiochemistry, Department of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim of Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
| | - Laura Reffert
- Department of Nuclear Medicine, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany
| | - Steffen Diehl
- Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim, Germany
| | - Stefan O Schönberg
- Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim, Germany
| | - Carmen Wängler
- Biomedical Chemistry, Department of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim of Heidelberg University, Mannheim, Germany
| | - Peter Hohenberger
- Division of Surgical Oncology and Thoracic Surgery, University Medical Center Mannheim, Mannheim, Germany
| | - Björn Wängler
- Molecular Imaging and Radiochemistry, Department of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim of Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
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Prognostic and Theranostic Applications of Positron Emission Tomography for a Personalized Approach to Metastatic Castration-Resistant Prostate Cancer. Int J Mol Sci 2021; 22:ijms22063036. [PMID: 33809749 PMCID: PMC8002334 DOI: 10.3390/ijms22063036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 01/25/2023] Open
Abstract
Metastatic castration-resistant prostate cancer (mCRPC) represents a condition of progressive disease in spite of androgen deprivation therapy (ADT), with a broad spectrum of manifestations ranging from no symptoms to severe debilitation due to bone or visceral metastatization. The management of mCRPC has been profoundly modified by introducing novel therapeutic tools such as antiandrogen drugs (i.e., abiraterone acetate and enzalutamide), immunotherapy through sipuleucel-T, and targeted alpha therapy (TAT). This variety of approaches calls for unmet need of biomarkers suitable for patients’ pre-treatment selection and prognostic stratification. In this scenario, imaging with positron emission computed tomography (PET/CT) presents great and still unexplored potential to detect specific molecular and metabolic signatures, some of whom, such as the prostate specific membrane antigen (PSMA), can also be exploited as therapeutic targets, thus combining diagnosis and therapy in the so-called “theranostic” approach. In this review, we performed a web-based and desktop literature research to investigate the prognostic and theranostic potential of several PET imaging probes, such as 18F-FDG, 18F-choline and 68Ga-PSMA-11, also covering the emerging tracers still in a pre-clinical phase (e.g., PARP-inhibitors’ analogs and the radioligands binding to gastrin releasing peptide receptors/GRPR), highlighting their potential for defining personalized care pathways in mCRPC.
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In Vivo Biodistribution and Efficacy Evaluation of NeoB, a Radiotracer Targeted to GRPR, in Mice Bearing Gastrointestinal Stromal Tumor. Cancers (Basel) 2021; 13:cancers13051051. [PMID: 33801382 PMCID: PMC7958597 DOI: 10.3390/cancers13051051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 12/11/2022] Open
Abstract
Simple Summary NeoB is undergoing evaluation as a novel theragnostic agent—that is, that it can be employed either for the diagnosis of tumor expressing gastrin-releasing peptide receptor (GRPR) using nuclear imaging, or for the therapy of such GRPR positive tumors using internal radiotherapy. The switch from diagnosis to therapy simply rely on the choice of the radioisotope that is coupled to NeoB. The aim of our study was to investigate—for the first time—the potency of NeoB for tumor therapy once labeled with the beta- emitter Lu-177. This study has been conducted in mice bearing human Gastrointestinal Stromal Tumors (GIST). [177Lu]Lu-NeoB was found to accumulate in the tumor, with only minimal retention in off-target organs. Consequently, mice treated with therapeutic doses of [177Lu]Lu-NeoB (37MBq/week for three weeks) exhibited tumor regression and therefore long term survival in comparison to the control untreated mice. Abstract NeoB is a radiotracer targeting the gastrin-releasing peptide receptor (GRPR), a G-protein–coupled receptor expressed in various cancers. The aim of the present study was to evaluate the biodistribution and efficacy of this new therapeutic agent in Gastrointestinal Stromal Tumors (GIST). Eighty-two SCID mice bearing GIST-882 tumors were employed. [177Lu]Lu-NeoB biodistribution was evaluated up to seven days by organ sampling (200 pmol/0.8 MBq, i.v.). For efficacy evaluation, mice received either saline, 400 pmol or 800 pmol of [177Lu]Lu-NeoB (37MBq, 1/w, 3 w, i.v.). SPECT/CT imaging was performed at 24 h, and tumor volume was determined up to 100 days. Elevated and specific [177Lu]Lu-NeoB uptake was found in the GIST tumor, as demonstrated by in vivo competition (19.1 ± 3.9 %ID/g vs. 0.3 ± 0.1 %ID/g at 4h). [177Lu]Lu-NeoB tumor retention (half-life of 40.2 h) resulted in elevated tumor-to-background ratios. Tumor volumes were significantly reduced in both treated groups (p < 0.01), even leading to complete tumor regression at the 400 pmol dose. [177Lu]Lu-NeoB exhibited excellent pharmacokinetics with elevated and prolonged tumor uptake and low uptake in non-target organs such as pancreas. The potential of this new theragnostic agent in different indications, including GIST, is under evaluation in the FIH [177Lu]Lu-NeoB clinical trial.
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Maina T, Thakur M. SPECT Radiochemistry. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00023-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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20
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Li X, Cai H, Wu X, Li L, Wu H, Tian R. New Frontiers in Molecular Imaging Using Peptide-Based Radiopharmaceuticals for Prostate Cancer. Front Chem 2020; 8:583309. [PMID: 33335885 PMCID: PMC7736158 DOI: 10.3389/fchem.2020.583309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/27/2020] [Indexed: 02/05/2023] Open
Abstract
The high incidence of prostate cancer (PCa) increases the need for progress in its diagnosis, staging, and precise treatment. The overexpression of tumor-specific receptors for peptides in human cancer cells, such as gastrin-releasing peptide receptor, natriuretic peptide receptor, and somatostatin receptor, has indicated the ideal molecular basis for targeted imaging and therapy. Targeting these receptors using radiolabeled peptides and analogs have been an essential topic on the current forefront of PCa studies. Radiolabeled peptides have been used to target receptors for molecular imaging in human PCa with high affinity and specificity. The radiolabeled peptides enable optimal quick elimination from blood and normal tissues, producing high contrast for positron emission computed tomography and single-photon emission computed tomography imaging with high tumor-to-normal tissue uptake ratios. Owing to their successful application in visualization, peptide derivatives with therapeutic radionuclides for peptide receptor radionuclide therapy in PCa have been explored in recent years. These developments offer the promise of personalized, molecular medicine for individual patients. Hence, we review the preclinical and clinical literature in the past 20 years and focus on the newer developments of peptide-based radiopharmaceuticals for the imaging and therapy of PCa.
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Affiliation(s)
- Xin Li
- Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Huawei Cai
- Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoai Wu
- Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Li Li
- Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Haoxing Wu
- Department of Nuclear Medicine, Frontiers Science Center for Disease-Related Molecular Network, National Clinical Research Center for Geriatrics, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, China
| | - Rong Tian
- Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China
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One Step Closer to Clinical Translation: Enhanced Tumor Targeting of [ 99mTc]Tc-DB4 and [ 111In]In-SG4 in Mice Treated with Entresto. Pharmaceutics 2020; 12:pharmaceutics12121145. [PMID: 33256013 PMCID: PMC7760338 DOI: 10.3390/pharmaceutics12121145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022] Open
Abstract
Background: Peptide radioligands may serve as radionuclide carriers to tumor sites overexpressing their cognate receptor for diagnostic or therapeutic purposes. Treatment of mice with the neprilysin (NEP)-inhibitor phosphoramidon was previously shown to improve the metabolic stability and tumor uptake of biodegradable radiopeptides. Aiming to clinical translation of this methodology, we herein investigated the impact of the approved pill Entresto, releasing the potent NEP-inhibitor LBQ657 in vivo, on the stability and tumor uptake of two radiopeptides. Methods: The metabolic stability of [99mTc]Tc-DB4 (DB4, N4-Pro-Gln-Arg-Tyr-Gly-Asn-Gln-Trp-Ala-Val-Gly-His-Leu-Nle-NH2) and [111In]In-SG4 (SG4, DOTA-DGlu-Ala-Tyr-Gly-Trp-Nle-Asp-Phe-NH2) was tested in LBQ657/Entresto-treated mice vs. untreated controls. The uptake in gastrin-releasing peptide receptor (GRPR)-, or cholecystokinin subtype 2 receptor (CCK2R)-positive tumors respectively, was compared between LBQ657/Entresto-treated mice and untreated controls. Results: LBQ657/Entresto treatment induced marked stabilization of [99mTc] Tc-DB4 and [111In]In-SG4 in peripheral mice blood, resulting in equally enhanced tumor uptake at 4 h post-injection. Accordingly, the [99mTc]Tc-DB4 uptake of 7.13 ± 1.76%IA/g in PC-3 tumors increased to 16.17 ± 0.71/17.50 ± 3.70%IA/g (LBQ657/Entresto) and the [111In]In-SG4 uptake of 3.07 ± 0.87%IA/g in A431-CCK2R(+) tumors to 8.11 ± 1.45/9.61 ± 1.70%IA/g. Findings were visualized by SPECT/CT. Conclusions: This study has shown the efficacy of Entresto to notably improve the profile of [99mTc]Tc-DB4 and [111In]In-SG4 in mice, paving the way for clinical translation of this approach.
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Luca SD, Verdoliva V, Saviano M. Peptide Ligands Specifically Targeting HER2 Receptor and the Role Played by a Synthetic Model System of the Receptor Extracellular Domain: Hypothesized Future Perspectives. J Med Chem 2020; 63:15333-15343. [PMID: 33226807 DOI: 10.1021/acs.jmedchem.0c01340] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A short (Fab)trastuzumab-derived peptide specific for HER2 receptor was identified. Its affinity for the model system HER2-DIVMP was found in a nanomolar range. The structural determinants responsible for the interaction between this ligand (A9) and HER2-DIVMP were investigated by both computational and NMR analysis. Next, the possibility of using A9 as HER2- specific probe for the nuclear medicine imaging was evaluated by conjugating A9 with the DTPA chelator and radiolabeling it with 111In. The developed probe retained a nanomolar affinity to HER2-overexpressing cancer cells, however, some unspecific binding also occurred. The peptide internalization into cells by receptor-mediated endocytosis was also studied. Future perspectives are aimed at using A9 as a probe for molecular imaging diagnostics as well as active targeting of anticancer drugs. Lead structure optimization is needed to minimize the percentage of A9 unspecific binding and to increase the binding affinity to the receptor.
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Affiliation(s)
- Stefania De Luca
- Institute of Biostructures and Bioimaging, National Research Council, 80134 Naples, Italy
| | - Valentina Verdoliva
- Institute of Biostructures and Bioimaging, National Research Council, 80134 Naples, Italy
| | - Michele Saviano
- Institute of Crystallography, National Research Council, 70126 Bari, Italy
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Abbasi Gharibkandi N, Conlon JM, Hosseinimehr SJ. Strategies for improving stability and pharmacokinetic characteristics of radiolabeled peptides for imaging and therapy. Peptides 2020; 133:170385. [PMID: 32822772 DOI: 10.1016/j.peptides.2020.170385] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 02/07/2023]
Abstract
Tumor cells overexpress a variety of receptors that are emerging targets in cancer chemotherapy. Radiolabeled peptides with high affinity and selectivity for these overexpressed receptors have been designed for both imaging and therapy purposes. Such peptides display advantages such as high selectivity for tumor cells, rapid tumor tissue penetration, and rapid clearance from non-target tissues and the circulation. However, the very short in vivo half-life of radiolabeled peptides, arising from enzymatic degradation and/or efficient clearance by the kidney, limits their accumulation in tumors. This review presents various strategies that have been applied to extend the half-life extension and improve the pharmacokinetic characteristics of radiolabeled peptides. These include amino acid substitution, modification of the peptide termini, dimerization and multimerization of the peptide, cyclization, conjugation with polymers, sugars and albumin and use of peptidase inhibitors.
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Affiliation(s)
- Nasrin Abbasi Gharibkandi
- Department of Radiopharmacy, Faculty of Pharmacy, Pharmaceutical Sciences Research Center, Mazandaran University of Medical Sciences, Sari, Iran; Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - J Michael Conlon
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Seyed Jalal Hosseinimehr
- Department of Radiopharmacy, Faculty of Pharmacy, Pharmaceutical Sciences Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
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[ 99mTc]Tc-DB1 Mimics with Different-Length PEG Spacers: Preclinical Comparison in GRPR-Positive Models. Molecules 2020; 25:molecules25153418. [PMID: 32731473 PMCID: PMC7435657 DOI: 10.3390/molecules25153418] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 02/07/2023] Open
Abstract
Background: The frequent overexpression of gastrin-releasing peptide receptors (GRPRs) in human cancers provides the rationale for delivering clinically useful radionuclides to tumor sites using peptide carriers. Radiolabeled GRPR antagonists, besides being safer for human use, have often shown higher tumor uptake and faster background clearance than agonists. We herein compared the biological profiles of the GRPR-antagonist-based radiotracers [99mTc]Tc-[N4-PEGx-DPhe6,Leu-NHEt13]BBN(6-13) (N4: 6-(carboxy)-1,4,8,11-tetraazaundecane; PEG: polyethyleneglycol): (i) [99mTc]Tc-DB7 (x = 2), (ii) [99mTc]Tc-DB13 (x = 3), and (iii) [99mTc]Tc-DB14 (x = 4), in GRPR-positive cells and animal models. The impact of in situ neprilysin (NEP)-inhibition on in vivo stability and tumor uptake was also assessed by treatment of mice with phosphoramidon (PA). Methods: The GRPR affinity of DB7/DB13/DB14 was determined in PC-3 cell membranes, and cell binding of the respective [99mTc]Tc-radioligands was assessed in PC-3 cells. Each of [99mTc]Tc-DB7, [99mTc]Tc-DB13, and [99mTc]Tc-DB14 was injected into mice without or with PA coinjection and 5 min blood samples were analyzed by HPLC. Biodistribution was conducted at 4 h postinjection (pi) in severe combined immunodeficiency disease (SCID) mice bearing PC-3 xenografts without or with PA coinjection. Results: DB7, -13, and -14 displayed single-digit nanomolar affinities for GRPR. The uptake rates of [99mTc]Tc-DB7, [99mTc]Tc-DB13, and [99mTc]Tc-DB14 in PC-3 cells was comparable and consistent with a radioantagonist profile. The radiotracers were found to be ≈70% intact in mouse blood and >94% intact after coinjection of PA. Treatment of mice with PA enhanced tumor uptake. Conclusions: The present study showed that increase of PEG-spacer length in the [99mTc]Tc-DB7-[99mTc]Tc-DB13-[99mTc]Tc-DB14 series had little effect on GRPR affinity, specific uptake in PC-3 cells, in vivo stability, or tumor uptake. A significant change in in vivo stability and tumor uptake was observed only after treatment of mice with PA, without compromising the favorably low background radioactivity levels.
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Kanellopoulos P, Kaloudi A, de Jong M, Krenning EP, Nock BA, Maina T. Key-Protease Inhibition Regimens Promote Tumor Targeting of Neurotensin Radioligands. Pharmaceutics 2020; 12:pharmaceutics12060528. [PMID: 32526874 PMCID: PMC7356968 DOI: 10.3390/pharmaceutics12060528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/05/2020] [Accepted: 06/06/2020] [Indexed: 02/06/2023] Open
Abstract
Neurotensin subtype 1 receptors (NTS1R) represent attractive molecular targets for directing radiolabeled neurotensin (NT) analogs to tumor lesions for diagnostic and therapeutic purposes. This approach has been largely undermined by the rapid in vivo degradation of linear NT-based radioligands. Herein, we aim to increase the tumor targeting of three 99mTc-labeled NT analogs by the in-situ inhibition of two key proteases involved in their catabolism. DT1 ([N4-Gly7]NT(7-13)), DT5 ([N4-βAla7,Dab9]NT(7-13)), and DT6 ([N4-βAla7,Dab9,Tle12]]NT(7-13)) were labeled with 99mTc. Their profiles were investigated in NTS1R-positive colon adenocarcinoma WiDr cells and mice treated or not with the neprilysin (NEP)-inhibitor phosphoramidon (PA) and/or the angiotensin converting enzyme (ACE)-inhibitor lisinopril (Lis). Structural modifications led to the partial stabilization of 99mTc-DT6 in peripheral mice blood (55.1 ± 3.9% intact), whereas 99mTc-DT1 and 99mTc-DT5 were totally degraded within 5 min. Coinjection of PA and/or Lis significantly stabilized all three analogs, leading to a remarkable enhancement of tumor uptake for 99mTc-DT1 and 99mTc-DT5, but was less effective in the case of poorly internalizing 99mTc-DT6. In conclusion, NEP and/or ACE inhibition represents a powerful tool to improve tumor targeting and the overall pharmacokinetics of NT-based radioligands, and warrants further validation in the field of NTS1R-targeted tumor imaging and therapy.
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Affiliation(s)
- Panagiotis Kanellopoulos
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
- Molecular Pharmacology, School of Medicine, University of Crete, 70013 Heraklion, Greece
| | - Aikaterini Kaloudi
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
| | - Marion de Jong
- Department of Radiology & Nuclear Medicine Erasmus MC, 3015 CN Rotterdam, The Netherlands;
| | - Eric P. Krenning
- Cyclotron Rotterdam BV, Erasmus MC, 3015 CE Rotterdam, The Netherlands;
| | - Berthold A. Nock
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR “Demokritos”, 15341 Athens, Greece; (P.K.); (A.K.); (B.A.N.)
- Correspondence: ; Tel.: +30-210-650-3908
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Tu Y, Tao J, Wang F, Liu P, Han Z, Li Z, Ma Y, Gu Y. A novel peptide targeting gastrin releasing peptide receptor for pancreatic neoplasm detection. Biomater Sci 2020; 8:2682-2693. [DOI: 10.1039/d0bm00162g] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The designed novel peptide GB-6 with targeted GRPR-binding possesses more favorable pharmacokinetic properties and metabolic stability, as well as superior tumor-targeting ability in pancreatic cancer models, relative to BBN7–14.
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Affiliation(s)
- Yuanbiao Tu
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
| | - Ji Tao
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
| | - Fang Wang
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
| | - Peifei Liu
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
| | - Zhihao Han
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
| | - Zhaolun Li
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
| | - Yi Ma
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
| | - Yueqing Gu
- State Key Laboratory of Natural Medicine
- Department of Biomedical Engineering
- School of Engineering
- China Pharmaceutical University
- Nanjing 210009
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High-throughput radio-TLC analysis. Nucl Med Biol 2019; 82-83:41-48. [PMID: 31891883 DOI: 10.1016/j.nucmedbio.2019.12.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/04/2019] [Accepted: 12/12/2019] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Radio thin layer chromatography (radio-TLC) is commonly used to analyze purity of radiopharmaceuticals or to determine the reaction conversion when optimizing radiosynthesis processes. In applications where there are few radioactive species, radio-TLC is preferred over radio-high-performance liquid chromatography due to its simplicity and relatively quick analysis time. However, with current radio-TLC methods, it remains cumbersome to analyze a large number of samples during reaction optimization. In a couple of studies, Cerenkov luminescence imaging (CLI) has been used for reading radio-TLC plates spotted with a variety of isotopes. We show that this approach can be extended to develop a high-throughput approach for radio-TLC analysis of many samples. METHODS The high-throughput radio-TLC analysis was carried out by performing parallel development of multiple radioactive samples spotted on a single TLC plate, followed by simultaneous readout of the separated samples using Cerenkov imaging. Using custom-written MATLAB software, images were processed and regions of interest (ROIs) were drawn to enclose the radioactive regions/spots. For each sample, the proportion of integrated signal in each ROI was computed. Various crude samples of [18F]fallypride, [18F]FET and [177Lu]Lu-PSMA-617 were prepared for demonstration of this new method. RESULTS Benefiting from a parallel developing process and high resolution of CLI-based readout, total analysis time for eight [18F]fallypride samples was 7.5 min (2.5 min for parallel developing, 5 min for parallel readout), which was significantly shorter than the 48 min needed using conventional approaches (24 min for sequential developing, 24 min for sequential readout on a radio-TLC scanner). The greater separation resolution of CLI enabled the discovery of a low-abundance side product from a crude [18F]FET sample that was not discernable using the radio-TLC scanner. Using the CLI-based readout method, we also observed that high labeling efficiency (99%) of [177Lu]Lu-PSMA-617 can be achieved in just 10 min, rather than the typical 30 min timeframe used. CONCLUSIONS Cerenkov imaging in combination with parallel developing of multiple samples on a single TLC plate proved to be a practical method for rapid, high-throughput radio-TLC analysis.
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Oroujeni M, Abouzayed A, Lundmark F, Mitran B, Orlova A, Tolmachev V, Rosenström U. Evaluation of Tumor-Targeting Properties of an Antagonistic Bombesin Analogue RM26 Conjugated with a Non-Residualizing Radioiodine Label Comparison with a Radiometal-Labelled Counterpart. Pharmaceutics 2019; 11:pharmaceutics11080380. [PMID: 31382362 PMCID: PMC6724035 DOI: 10.3390/pharmaceutics11080380] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/16/2019] [Accepted: 07/24/2019] [Indexed: 12/24/2022] Open
Abstract
Radiolabelled antagonistic bombesin analogues are successfully used for targeting of gastrin-releasing peptide receptors (GRPR) that are overexpressed in prostate cancer. Internalization of antagonistic bombesin analogues is slow. We hypothesized that the use of a non-residualizing radioiodine label might not affect the tumour uptake but would reduce the retention in normal organs, where radiopharmaceutical would be internalized. To test this hypothesis, tyrosine was conjugated via diethylene glycol linker to N-terminus of an antagonistic bombesin analogue RM26 to form Tyr-PEG2-RM26. [111In]In-DOTA-PEG2-RM26 was used as a control with a residualizing label. Tyr-PEG2-RM26 was labelled with 125I with 95% radiochemical purity and retained binding specificity to GRPR. The IC50 values for Tyr-PEG2-RM26 and DOTA-PEG2-RM26 were 1.7 ± 0.3 nM and 3.3 ± 0.5 nM, respectively. The cellular processing of [125I]I-Tyr-PEG2-RM26 by PC-3 cells showed unusually fast internalization. Biodistribution showed that uptake in pancreas and tumour was GRPR-specific for both radioconjugates. Blood clearance of [125I]I-Tyr-PEG2-RM26 was appreciably slower and activity accumulation in all organs was significantly higher than for [111In]In-DOTA-PEG2-RM26. Tumor uptake of [111In]In-DOTA-PEG2-RM26 was significantly higher than for [125I]I-Tyr-PEG2-RM26, resulting in higher tumour-to-organ ratio for [111In]In-DOTA-PEG2-RM26 at studied time points. Incorporation of amino acids with hydrophilic side-chains next to tyrosine might overcome the problems associated with the use of tyrosine as a prosthetic group for radioiodination.
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Affiliation(s)
- Maryam Oroujeni
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Ayman Abouzayed
- Department of Medicinal Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Fanny Lundmark
- Department of Medicinal Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Bogdan Mitran
- Department of Medicinal Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Anna Orlova
- Department of Medicinal Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
- Science for Life Laboratory, Uppsala University, SE-750 03 Uppsala, Sweden
| | - Vladimir Tolmachev
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden.
| | - Ulrika Rosenström
- Department of Medicinal Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
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Mitran B, Rinne SS, Konijnenberg MW, Maina T, Nock BA, Altai M, Vorobyeva A, Larhed M, Tolmachev V, de Jong M, Rosenström U, Orlova A. Trastuzumab cotreatment improves survival of mice with PC-3 prostate cancer xenografts treated with the GRPR antagonist 177 Lu-DOTAGA-PEG 2 -RM26. Int J Cancer 2019; 145:3347-3358. [PMID: 31077356 PMCID: PMC6852655 DOI: 10.1002/ijc.32401] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 04/19/2019] [Accepted: 05/02/2019] [Indexed: 12/24/2022]
Abstract
Gastrin‐releasing peptide receptors (GRPRs) are overexpressed in prostate cancer and are suitable for targeted radionuclide therapy (TRT). We optimized the bombesin‐derived GRPR‐antagonist PEG2‐RM26 for labeling with 177Lu and further determined the effect of treatment with 177Lu‐labeled peptide alone or in combination with the anti‐HER2 antibody trastuzumab in a murine model. The PEG2‐RM26 analog was coupled to NOTA, NODAGA, DOTA and DOTAGA chelators. The peptide‐chelator conjugates were labeled with 177Lu and characterized in vitro and in vivo. A preclinical therapeutic study was performed in PC‐3 xenografted mice. Mice were treated with intravenous injections (6 cycles) of (A) PBS, (B) DOTAGA‐PEG2‐RM26, (C) 177Lu‐DOTAGA‐PEG2‐RM26, (D) trastuzumab or (E) 177Lu‐DOTAGA‐PEG2‐RM26 in combination with trastuzumab. 177Lu‐DOTAGA‐PEG2‐RM26 demonstrated quantitative labeling yield at high molar activity (450 GBq/μmol), high in vivo stability (5 min pi >98% of radioligand remained when coinjected with phosphoramidon), high affinity to GRPR (KD = 0.4 ± 0.2 nM), and favorable biodistribution (1 hr pi tumor uptake was higher than in healthy tissues, including the kidneys). Therapy with 177Lu‐DOTAGA‐PEG2‐RM26 induced a significant inhibition of tumor growth. The median survival for control groups was significantly shorter than for treated groups (Group C 66 days, Group E 74 days). Trastuzumab together with radionuclide therapy significantly improved survival. No treatment‐related toxicity was observed. In conclusion, based on in vitro and in vivo characterization of the four 177Lu‐labeled PEG2‐RM26 analogs, we concluded that 177Lu‐DOTAGA‐PEG2‐RM26 was the most promising analog for TRT. Radiotherapy using 177Lu‐DOTAGA‐PEG2‐RM26 effectively inhibited tumor growth in vivo in a murine prostate cancer model. Anti‐HER2 therapy additionally improved survival. What's new? Targeted radionuclide therapy (TRT) using radiolabeled peptides seeking gastrin‐releasing peptide receptors (GRPRs) in tumors is a promising approach to treat disseminated prostate cancer. The possibility to improve the therapeutic index via combination therapies also warrants further investigation. Here, the authors developed and characterized a promising GRPR‐targeting radioligand and demonstrated its therapeutic efficacy in prostate cancer xenografts. Moreover, this study using the anti‐HER2 antibody trastuzumab presents the first in vivo proof‐of‐principle that the effects of anti‐GRPR radiotherapy can be amplified by co‐administration of anti‐HER2 treatment leading to prolonged survival.
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Affiliation(s)
- Bogdan Mitran
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Sara S Rinne
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Mark W Konijnenberg
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Athens, Greece
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Athens, Greece
| | - Mohamed Altai
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Anzhelika Vorobyeva
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Mats Larhed
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden.,Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Vladimir Tolmachev
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Marion de Jong
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Ulrika Rosenström
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Anna Orlova
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden.,Science for Life Laboratory, Uppsala University, Uppsala, Sweden
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Bakker IL, van Tiel ST, Haeck J, Doeswijk GN, de Blois E, Segbers M, Maina T, Nock BA, de Jong M, Dalm SU. In Vivo Stabilized SB3, an Attractive GRPR Antagonist, for Pre- and Intra-Operative Imaging for Prostate Cancer. Mol Imaging Biol 2019; 20:973-983. [PMID: 29556947 PMCID: PMC6244536 DOI: 10.1007/s11307-018-1185-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Purpose The gastrin-releasing peptide receptor (GRPR), overexpressed on various tumor types, is an attractive target for receptor-mediated imaging and therapy. Another interesting approach would be the use of GRPR radioligands for pre-operative imaging and subsequent radio-guided surgery, with the goal to improve surgical outcome. GRPR radioligands were successfully implemented in clinical studies, especially Sarabesin 3 (SB3) is an appealing GRPR antagonist with high receptor affinity. Gallium-68 labeled SB3 has good in vivo stability, after labeling with Indium-111; however, the molecule shows poor in vivo stability, which negatively impacts tumor-targeting capacity. A novel approach to increase in vivo stability of radiopeptides is by co-administration of the neutral endopeptidase (NEP) inhibitor, phosphoramidon (PA). We studied in vivo stability and biodistribution of [111In]SB3 without/with (−/+) PA in mice. Furthermore, SPECT/MRI on a novel, state-of-the-art platform was performed. Procedures GRPR affinity of SB3 was determined on PC295 xenograft sections using [125I]Tyr4-bombesin with tracer only or with increasing concentrations of SB3. For in vivo stability, mice were injected with 200/2000 pmol [111In]SB3 −/+ 300 μg PA. Blood was collected and analyzed. Biodistribution and SPECT/MRI studies were performed at 1, 4, and 24 h postinjection (p.i.) of 2.5 MBq/200 pmol or 25 MBq/200 pmol [111In]SB3 −/+ 300 μg PA in PC-3-xenografted mice. Results SB3 showed high affinity for GRPR (IC50 3.5 nM). Co-administration of PA resulted in twice higher intact peptide in vivo vs [111In]SB3 alone. Biodistribution studies at 1, 4, and 24 h p.i. show higher tumor uptake values with PA co-administration (19.7 ± 3.5 vs 10.2 ± 1.5, 17.6 ± 5.1 vs 8.3 ± 1.1, 6.5 ± 3.3 vs 3.1 ± 1.9 % ID/g tissue (P < 0.0001)). Tumor imaging with SPECT/MRI clearly improved after co-injection of PA. Conclusions Co-administration of PA increased in vivo tumor targeting capacity of [111In]SB3, making this an attractive combination for GRPR-targeted tumor imaging.
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Affiliation(s)
- Ingrid L Bakker
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands.
| | - Sandra T van Tiel
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands
| | - Joost Haeck
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands
| | - Gabriela N Doeswijk
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands
| | - Erik de Blois
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands
| | - Marcel Segbers
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands
| | - Theodosia Maina
- Molecular Radiopharmacy, INSRATES, NCSR "Demokritos", Athens, Greece
| | - Berthold A Nock
- Molecular Radiopharmacy, INSRATES, NCSR "Demokritos", Athens, Greece
| | - Marion de Jong
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands
| | - Simone U Dalm
- Department of Radiology and Nuclear Medicine, Erasmus MC, Room No. Na2510, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands
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Kaloudi A, Lymperis E, Kanellopoulos P, Waser B, de Jong M, Krenning EP, Reubi JC, Nock BA, Maina T. Localization of 99mTc-GRP Analogs in GRPR-Expressing Tumors: Effects of Peptide Length and Neprilysin Inhibition on Biological Responses. Pharmaceuticals (Basel) 2019; 12:ph12010042. [PMID: 30897789 PMCID: PMC6469168 DOI: 10.3390/ph12010042] [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: 02/26/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023] Open
Abstract
The overexpression of gastrin-releasing peptide receptors (GRPRs) in frequently occurring human tumors has provided the opportunity to use bombesin (BBN) analogs as radionuclide carriers to cancer sites for diagnostic and therapeutic purposes. We have been alternatively exploring human GRP motifs of higher GRPR selectivity compared to frog BBN sequences aiming to improve pharmacokinetic profiles. In the present study, we compared two differently truncated human endogenous GRP motifs: GRP(14–27) and GRP(18–27). An acyclic tetraamine was coupled at the N-terminus to allow for stable binding of the SPECT radionuclide 99mTc. Their biological profiles were compared in PC-3 cells and in mice without or with coinjection of phosphoramidon (PA) to induce transient neprilysin (NEP) inhibition in vivo. The two 99mTc-N4-GRP(14/18–27) radioligands displayed similar biological behavior in mice. Coinjection of PA exerted a profound effect on in vivo stability and translated into notably improved radiolabel localization in PC-3 experimental tumors. Hence, this study has shown that promising 99mTc-radiotracers for SPECT imaging may indeed derive from human GRP sequences. Radiotracer bioavailability was found to be of major significance. It could be improved during in situ NEP inhibition resulting in drastically enhanced uptake in GRPR-expressing lesions.
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Affiliation(s)
- Aikaterini Kaloudi
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", 15310 Athens, Greece.
| | - Emmanouil Lymperis
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", 15310 Athens, Greece.
| | | | - Beatrice Waser
- Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, CH-3010 Berne, Switzerland.
| | - Marion de Jong
- Department of Radiology & Nuclear Medicine Erasmus MC, 3015 CN Rotterdam, The Netherlands.
| | - Eric P Krenning
- Cytrotron Rotterdam BV, Erasmus MC, 3015 CN Rotterdam, The Netherlands.
| | - Jean Claude Reubi
- Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, CH-3010 Berne, Switzerland.
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", 15310 Athens, Greece.
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", 15310 Athens, Greece.
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Zhuo L, Yang X, Liao W, Wang J, Wang H, Lv M, Wang G, Song H, Feng Y, Chen Y, Wei H, Yang Y, Zhao P. Comparative cell uptake study of FITC-/177Lu-labeled RM26 monomer, dimer and trimer on PC-3: improving binding affinity of gastrin releasing peptide receptor (GRPR) antagonist via bivalency/trivalency. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-018-6396-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Lv M, Zhao P, Zhuo L, Liao W, Wang H, Yang X, Wang J, Wang G, Song H, Feng Y, Chen Y, Yang Y, Wei H. Binding and cytotoxicity of 131I-labeled gastrin-releasing peptide receptor antagonists modified by cell penetrating peptides. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-018-6307-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Galgano SJ, Valentin R, McConathy J. Role of PET imaging for biochemical recurrence following primary treatment for prostate cancer. Transl Androl Urol 2018; 7:S462-S476. [PMID: 30363475 PMCID: PMC6178324 DOI: 10.21037/tau.2018.06.09] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Prostate cancer is one of the most common cancers in men worldwide, and primary prostate cancer is typically treated with surgery, radiation, androgen deprivation, or a combination of these therapeutic modalities. Despite technical advances, approximately 30% of men will experience biochemical recurrent within 10 years of definitive treatment. Upon detection of a rise in serum prostate specific antigen (PSA), there is great need to accurately stage these patients to help guide further therapy. As a result, there are considerable efforts underway to establish the role of positron emission tomography (PET) in the diagnostic algorithm of biochemically recurrent prostate cancer. This manuscript provides an overview of PET tracers used for the detection and localization of prostate cancer in the setting of biochemical recurrence with a focus on PET tracers that are currently being used in clinical practice in the United States.
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Affiliation(s)
- Samuel J Galgano
- Department of Radiology, Section of Molecular Imaging and Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Roberto Valentin
- Department of Radiology, Section of Molecular Imaging and Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jonathan McConathy
- Department of Radiology, Section of Molecular Imaging and Therapeutics, University of Alabama at Birmingham, Birmingham, AL, USA
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Lymperis E, Kaloudi A, Sallegger W, Bakker IL, Krenning EP, de Jong M, Maina T, Nock BA. Radiometal-Dependent Biological Profile of the Radiolabeled Gastrin-Releasing Peptide Receptor Antagonist SB3 in Cancer Theranostics: Metabolic and Biodistribution Patterns Defined by Neprilysin. Bioconjug Chem 2018; 29:1774-1784. [PMID: 29664606 DOI: 10.1021/acs.bioconjchem.8b00225] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Recent advances in oncology involve the use of diagnostic/therapeutic radionuclide-carrier pairs that target cancer cells, offering exciting opportunities for personalized patient treatment. Theranostic gastrin-releasing peptide receptor (GRPR)-directed radiopeptides have been proposed for the management of GRPR-expressing prostate and breast cancers. We have recently introduced the PET tracer 68Ga-SB3 (SB3, DOTA- p-aminomethylaniline-diglycolic acid-DPhe-Gln-Trp-Ala-Val-Gly-His-Leu-NHEt), a receptor-radioantagonist that enables the visualization of GRPR-positive lesions in humans. Aiming to fully assess the theranostic potential of SB3, we herein report on the impact of switching 68Ga to 111In/177Lu-label on the biological properties of resulting radiopeptides. Notably, the bioavailability of 111In/177Lu-SB3 in mice drastically deteriorated compared with metabolically robust 68Ga-SB3, and as a result led to poorer 111In/177Lu-SB3 uptake in GRPR-positive PC-3 xenografts. The peptide cleavage sites were identified by chromatographic comparison of blood samples from mice intravenously receiving 111In/177Lu-SB3 with each of newly synthesized 111In/177Lu-SB3-fragments. Coinjection of the radioconjugates with the neprilysin (NEP)-inhibitor phosphoramidon led to full stabilization of 111In/177Lu-SB3 in peripheral mouse blood and resulted in markedly enhanced radiolabel uptake in the PC-3 tumors. In conclusion, in situ NEP-inhibition led to indistinguishable 68Ga/111In/177Lu-SB3 profiles in mice emphasizing the theranostic prospects of SB3 for clinical use.
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Affiliation(s)
- Emmanouil Lymperis
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-15310 Athens , Greece
| | - Aikaterini Kaloudi
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-15310 Athens , Greece
| | | | - Ingrid L Bakker
- Department of Radiology & Nuclear Medicine , Erasmus MC , 3015 CN Rotterdam , The Netherlands
| | - Eric P Krenning
- Cyclotron Rotterdam BV , Erasmus MC , 3015 CE Rotterdam , The Netherlands
| | - Marion de Jong
- Department of Radiology & Nuclear Medicine , Erasmus MC , 3015 CN Rotterdam , The Netherlands
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-15310 Athens , Greece
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-15310 Athens , Greece
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Nock BA, Charalambidis D, Sallegger W, Waser B, Mansi R, Nicolas GP, Ketani E, Nikolopoulou A, Fani M, Reubi JC, Maina T. New Gastrin Releasing Peptide Receptor-Directed [ 99mTc]Demobesin 1 Mimics: Synthesis and Comparative Evaluation. J Med Chem 2018. [PMID: 29517903 DOI: 10.1021/acs.jmedchem.8b00177] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We have previously reported on the gastrin releasing peptide receptor (GRPR) antagonist [99mTc]1, ([99mTc]demobesin 1, 99mTc-[N4'-diglycolate-dPhe6,Leu-NHEt13]BBN(6-13)). [99mTc]1 has shown superior biological profile compared to analogous agonist-based 99mTc-radioligands. We herein present a small library of [99mTc]1 mimics generated after structural modifications in (a) the linker ([99mTc]2, [99mTc]3, [99mTc]4), (b) the peptide chain ([99mTc]5, [99mTc]6), and (c) the C-terminus ([99mTc]7 or [99mTc]8). The effects of above modifications on the biological properties of analogs were studied in PC-3 cells and tumor-bearing SCID mice. All analogs showed subnanomolar affinity for the human GRPR, while most receptor-affine 4 and 8 behaved as potent GRPR antagonists in a functional internalization assay. In mice bearing PC-3 tumors, [99mTc]1-[99mTc]6 exhibited GRPR-specific tumor uptake, rapidly clearing from normal tissues. [99mTc]4 displayed the highest tumor uptake (28.8 ± 4.1%ID/g at 1 h pi), which remained high even after 24 h pi (16.3 ± 1.8%ID/g), well surpassing that of [99mTc]1 (5.4 ± 0.7%ID/g at 24 h pi).
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Affiliation(s)
- Berthold A Nock
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-153 10 Athens , Greece
| | - David Charalambidis
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-153 10 Athens , Greece
| | | | - Beatrice Waser
- Cell Biology and Experimental Cancer Research, Institute of Pathology , University of Berne , CH-3010 Berne , Switzerland
| | | | | | - Eleni Ketani
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-153 10 Athens , Greece
| | - Anastasia Nikolopoulou
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-153 10 Athens , Greece
| | | | - Jean-Claude Reubi
- Cell Biology and Experimental Cancer Research, Institute of Pathology , University of Berne , CH-3010 Berne , Switzerland
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES , National Center for Scientific Research "Demokritos" , GR-153 10 Athens , Greece
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Evaluation of HER2-specific peptide ligand for its employment as radiolabeled imaging probe. Sci Rep 2018; 8:2998. [PMID: 29445216 PMCID: PMC5812989 DOI: 10.1038/s41598-018-21283-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 02/01/2018] [Indexed: 01/19/2023] Open
Abstract
HER2 transmembrane receptor is an important target in immunotherapy treatment of breast and gastroesophageal cancer. Molecular imaging of HER2 expression may provide essential prognostic and predictive information concerning disseminated cancer and aid in selection of an optimal therapy. Radiolabeled low molecular weight peptide ligands are particularly attractive as probes for molecular imaging, since they reach and bind to the target and clear from non-target organs and blood stream faster than bulky antibodies. In this study, we evaluated a potential HER2-imaging probe, an A9 nonapeptide, derived from the trastuzumab-Fab portion. Its cellular uptake was investigated by mass spectrometry analysis of the cytoplasmic cellular extracts. Moreover, based on in-silico modeling, DTPA chelator was conjugated to N-terminus of A9. 111In-labeled A9 demonstrated nanomolar affinity to HER2-expressing BT474 cells and favorable biodistribution profile in NMRI mice. This study suggests that the peptide A9 represents a good lead candidate for development of molecular probe, to be used for imaging purposes and for the delivery of cytotoxic agents.
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NeoBOMB1, a GRPR-Antagonist for Breast Cancer Theragnostics: First Results of a Preclinical Study with [ 67Ga]NeoBOMB1 in T-47D Cells and Tumor-Bearing Mice. Molecules 2017; 22:molecules22111950. [PMID: 29137110 PMCID: PMC6150197 DOI: 10.3390/molecules22111950] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/06/2017] [Accepted: 11/08/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The GRPR-antagonist-based radioligands [67/68Ga/111In/177Lu]NeoBOMB1 have shown excellent theragnostic profiles in preclinical prostate cancer models, while [68Ga]NeoBOMB1 effectively visualized prostate cancer lesions in patients. We were further interested to explore the theragnostic potential of NeoBOMB1 in GRPR-positive mammary carcinoma, by first studying [67Ga]NeoBOMB1 in breast cancer models; Methods: We investigated the profile of [67Ga]NeoBOMB1, a [68Ga]NeoBOMB1 surrogate, in GRPR-expressing T-47D cells and animal models; Results: NeoBOMB1 (IC50s of 2.2 ± 0.2 nM) and [natGa]NeoBOMB1 (IC50s of 2.5 ± 0.2 nM) exhibited high affinity for the GRPR. At 37 °C [67Ga]NeoBOMB1 strongly bound to the T-47D cell-membrane (45.8 ± 0.4% at 2 h), internalizing poorly, as was expected for a radioantagonist. [67Ga]NeoBOMB1 was detected >90% intact in peripheral mouse blood at 30 min pi. In mice bearing T-47D xenografts, [67Ga]NeoBOMB1 specifically localized in the tumor (8.68 ± 2.9% ID/g vs. 0.6 ± 0.1% ID/g during GRPR-blockade at 4 h pi). The unfavorably high pancreatic uptake could be considerably reduced (206.29 ± 17.35% ID/g to 42.46 ± 1.31% ID/g at 4 h pi) by increasing the NeoBOMB1 dose from 10 pmol to 200 pmol, whereas tumor uptake remained unaffected. Notably, tumor values did not decline from 1 to 24 h pi; Conclusions: [67Ga]NeoBOMB1 can successfully target GRPR-positive breast cancer in animals with excellent prospects for clinical translation.
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Zarzour JG, Galgano S, McConathy J, Thomas JV, Rais-Bahrami S. Lymph node imaging in initial staging of prostate cancer: An overview and update. World J Radiol 2017; 9:389-399. [PMID: 29104741 PMCID: PMC5661167 DOI: 10.4329/wjr.v9.i10.389] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/26/2017] [Accepted: 07/17/2017] [Indexed: 02/06/2023] Open
Abstract
Accurate nodal staging at the time of diagnosis of prostate cancer is crucial in determining a treatment plan for the patient. Pelvic lymph node dissection is the most reliable method, but is less than perfect and has increased morbidity. Cross sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) are non-invasive tools that rely on morphologic characteristics such as shape and size of the lymph nodes. However, lymph nodes harboring metastatic disease may be normal sized and non-metastatic lymph nodes may be enlarged due to reactive hyperplasia. The optimal strategy for preoperative staging remains a topic of ongoing research. Advanced imaging techniques to assess lymph nodes in the setting of prostate cancer utilizing novel MRI contrast agents as well as positron emission tomography (PET) tracers have been developed and continue to be studied. Magnetic resonance lymphography utilizing ultra-small super paramagnetic iron oxide has shown promising results in detection of metastatic lymph nodes. Combining MRL with diffusion-weighted imaging may also improve accuracy. Considerable efforts are being made to develop effective PET radiotracers that are performed using hybrid-imaging systems that combine PET with CT or MRI. PET tracers that will be reviewed in this article include [18F]fluoro-D-glucose, sodium [18F]fluoride, [18F]choline, [11C]choline, prostate specific membrane antigen binding ligands, [11C]acetate, [18F]fluciclovine, gastrin releasing peptide receptor ligands, and androgen binding receptors. This article will review these advanced imaging modalities and ability to detect prostate cancer metastasis to lymph nodes. While more research is needed, these novel techniques to image lymph nodes in the setting of prostate cancer show a promising future in improving initial lymph node staging.
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Affiliation(s)
- Jessica G Zarzour
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35249, United States
| | - Sam Galgano
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35249, United States
| | - Jonathan McConathy
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35249, United States
| | - John V Thomas
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35249, United States
| | - Soroush Rais-Bahrami
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35249, United States
- Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35249, United States
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Martinez J. Joseph Rudinger memorial lecture: Unexpected functions of angiotensin converting enzyme, beyond its enzymatic activity. J Pept Sci 2017. [DOI: 10.1002/psc.3022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jean Martinez
- Institut des Biomolécules Max Mousseron; UMR 5247 CNRS-Université de Montpellier-ENSCM; Faculté de Pharmacie, 15 Avenue Charles Flahault 34093 Montpellier Cedex 5 France
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Maina T, Nock BA, Kulkarni H, Singh A, Baum RP. Theranostic Prospects of Gastrin-Releasing Peptide Receptor–Radioantagonists in Oncology. PET Clin 2017; 12:297-309. [DOI: 10.1016/j.cpet.2017.02.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Maina T, Kaloudi A, Valverde IE, Mindt TL, Nock BA. Amide-to-triazole switch vs. in vivo NEP-inhibition approaches to promote radiopeptide targeting of GRPR-positive tumors. Nucl Med Biol 2017. [PMID: 28636973 DOI: 10.1016/j.nucmedbio.2017.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Radiolabeled bombesin (BBN)-analogs have been proposed for diagnosis and therapy of gastrin-releasing peptide receptor (GRPR)-expressing tumors, such as prostate, breast and lung cancer. Metabolic stability represents a crucial factor for the success of this approach by ensuring sufficient delivery of circulating radioligand to tumor sites. The amide-to-triazole switch on the backbone of DOTA-PEG4-[Nle14]BBN(7-14) (1) was reported to improve the in vitro stability of resulting 177Lu-radioligands. On the other hand, in-situ inhibition of neutral endopeptidase (NEP) by coinjection of phosphoramidon (PA) was shown to significantly improve the in vivo stability and tumor uptake of biodegradable radiopeptides. We herein compare the impact of the two methods on the bioavailability and localization of 177Lu-DOTA-PEG4-[Nle14]BBN(7-14) analogs in GRPR-positive tumors in mice. METHODS The 1,4-disubstituted [1-3]-triazole was used to replace one (2: Gly11-His12; 3: Ala9-Val10) or two (4: Ala9-Val10 and Gly11-His12) peptide bonds in 1 (reference) and all compounds were labeled with 177Lu. Each of [177Lu]1-[177Lu]4 was injected without (control) or with PA in healthy mice. Blood samples collected 5min post-injection (pi) were analyzed by HPLC. Biodistribution of [177Lu]1-[177Lu]4 was conducted in SCID mice bearing human prostate adenocarcinoma PC-3 xenografts at 4h pi. Groups of 4 animals were injected with radioligand, alone (controls), or with coinjection of PA, or of a mixture of PA and excess and [Tyr4]BBN to determine GRPR-specificity of uptake (Block). RESULTS The in vivo stability of the radioligands was: [177Lu]1 (25% intact), [177Lu]2 (45% intact), [177Lu]3 (30% intact) and [177Lu]4 (40% intact). By PA-coinjection these values notably increased to 90%-93%. Moreover, treatment with PA induced an impressive and GRPR-specific uptake of all radioligands in the PC-3 xenografts at 4h pi: [177Lu]1: 4.7±0.4 to 24.8±4.9%ID/g; [177Lu]2: 8.3±1.2 to 26.0±1.1%ID/g; [177Lu]3: 6.6±0.4 to 21.3±4.4%ID/g; and [177Lu]4: 4.8±1.6 to 13.7±3.8%ID/g. CONCLUSIONS This study has shown that amide-to-triazole substitutions in 177Lu-DOTA-PEG4-[Nle14]BBN(7-14) induced minor effects on bioavailability and tumor uptake in mice models, whereas in-situ NEP-inhibition(s) by PA impressively improved in vivo profiles.
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Affiliation(s)
- Theodosia Maina
- Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos", Athens, Greece
| | - Aikaterini Kaloudi
- Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos", Athens, Greece
| | - Ibai E Valverde
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS-UBFC, Université de Bourgogne Franche-Comté, Dijon, France
| | - Thomas L Mindt
- Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Institute Applied Diagnostics, General Hospital of Vienna, Vienna, Austria.
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos", Athens, Greece.
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Singh A, Kulkarni HR, Baum RP. Imaging of Prostate Cancer Using 64 Cu-Labeled Prostate-Specific Membrane Antigen Ligand. PET Clin 2017; 12:193-203. [DOI: 10.1016/j.cpet.2016.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Maina T, Nock BA. From Bench to Bed: New Gastrin-Releasing Peptide Receptor-Directed Radioligands and Their Use in Prostate Cancer. PET Clin 2017; 12:205-217. [PMID: 28267454 DOI: 10.1016/j.cpet.2016.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Gastrin-releasing peptide receptors (GRPRs) are overexpressed in prostate and breast cancer, and are therefore attractive molecular targets for diagnosis and therapy with radiolabeled GRPR-directed peptide probes. The amphibian tetradecapeptide bombesin or the mammalian gastrin-releasing peptide and neuromedin C have been modified with a variety of chelators. As a result, labeling with radiometals attractive for SPECT or PET imaging and for radionuclide therapy has led to the development of peptide radioligands suitable for in vivo targeting of prostate cancer. A shift of paradigm from internalizing GRPR-agonists to antagonists has occurred owing to the higher biosafety and superior pharmacokinetics of radioantagonists.
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Affiliation(s)
- Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Agia Paraskevi, Attikis, Athens 15310, Greece.
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Agia Paraskevi, Attikis, Athens 15310, Greece
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Kaloudi A, Nock BA, Lymperis E, Krenning EP, de Jong M, Maina T. Improving the In Vivo Profile of Minigastrin Radiotracers: A Comparative Study Involving the Neutral Endopeptidase Inhibitor Phosphoramidon. Cancer Biother Radiopharm 2016; 31:20-8. [PMID: 26844849 DOI: 10.1089/cbr.2015.1935] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Minigastrin radiotracers, such as [(111)In-DOTA]MG0 ([(111)In-DOTA-DGlu(1)]minigastrin), have been considered for diagnostic imaging and radionuclide therapy of CCK2R-positive human tumors, such as medullary thyroid carcinoma. However, the high kidney retention assigned to the pentaGlu(2-6) repeat in the peptide sequence has compromised their clinical applicability. On the other hand, truncated des(Glu)(2-6)-analogs, such as [(111)In-DOTA]MG11 ([(111)In-DOTA-DGlu(10),desGlu(2-6)]minigastrin), despite their low renal uptake, show poor bioavailability and tumor targeting. [(111)In]CP04 ([(111)In-DOTA-DGlu(1-6)]minigastrin) acquired by Glu(2-6)/DGlu(2-6) substitution showed promising tumor-to-kidney ratios in rodents. In the present study, we compare the biological profiles of [(111)In]CP04, [(111)In-DOTA]MG11, and [(111)In-DOTA]MG0 during in situ neutral endopeptidase (NEP) inhibition, recently shown to improve the bioavailability of several peptide radiotracers. After coinjection of the NEP inhibitor, phosphoramidon (PA), the stability of [(111)In]CP04 and [(111)In-DOTA]MG0 in peripheral mouse blood increased, with an exceptional >14-fold improvement monitored for [(111)In-DOTA]MG11. In line with these findings, PA treatment increased the uptake of [(111)In]CP04 (8.5 ± 0.4%ID/g to 16.0 ± 2.3%ID/g) and [(111)In-DOTA]MG0 (11.9 ± 2.2%ID/g to 17.2 ± 0.9%ID/g) in A431-CCK2R(+) tumors at 4 hours postinjection, whereas the respective increase for [(111)In-DOTA]MG11 was >6-fold (2.5 ± 0.9%ID/g to 15.1 ± 1.7%ID/g). Interestingly, kidney uptake remained lowest for [(111)In-DOTA]MG11, but unfavorably increased by PA treatment for [(111)In-DOTA]MG0. Thus, overall, the most favorable in vivo profile was displayed by [(111)In-DOTA]MG11 during NEP inhibition, highlighting the need to validate this promising concept in the clinic.
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Affiliation(s)
- Aikaterini Kaloudi
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Berthold A Nock
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Emmanouil Lymperis
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
| | - Eric P Krenning
- 2 Department of Nuclear Medicine, Erasmus MC , Rotterdam, The Netherlands
| | - Marion de Jong
- 2 Department of Nuclear Medicine, Erasmus MC , Rotterdam, The Netherlands .,3 Department of Radiology, Erasmus MC , Rotterdam, The Netherlands
| | - Theodosia Maina
- 1 Molecular Radiopharmacy, INRASTES, National Center for Scientific Research "Demokritos ," Athens, Greece
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Dalm SU, Bakker IL, de Blois E, Doeswijk GN, Konijnenberg MW, Orlandi F, Barbato D, Tedesco M, Maina T, Nock BA, de Jong M. 68Ga/177Lu-NeoBOMB1, a Novel Radiolabeled GRPR Antagonist for Theranostic Use in Oncology. J Nucl Med 2016; 58:293-299. [DOI: 10.2967/jnumed.116.176636] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/17/2016] [Indexed: 11/16/2022] Open
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Nock BA, Kaloudi A, Lymperis E, Giarika A, Kulkarni HR, Klette I, Singh A, Krenning EP, de Jong M, Maina T, Baum RP. Theranostic Perspectives in Prostate Cancer with the Gastrin-Releasing Peptide Receptor Antagonist NeoBOMB1: Preclinical and First Clinical Results. J Nucl Med 2016; 58:75-80. [DOI: 10.2967/jnumed.116.178889] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 07/13/2016] [Indexed: 12/22/2022] Open
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Yang R, Liu P, Pan D, Zhang P, Bai Z, Xu Y, Wang L, Yan J, Yan Y, Liu X, Yang M. An Investigation on a Novel Anti-tumor Fusion Peptide of FSH33-53-IIKK. J Cancer 2016; 7:1010-9. [PMID: 27313792 PMCID: PMC4910594 DOI: 10.7150/jca.14425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 03/15/2016] [Indexed: 12/12/2022] Open
Abstract
A novel fusion peptide FSH33-53-IIKK was designed and expected to combine the follicle stimulating hormone receptor (FSHR) targeting and tumor toxicity. In vitro and in vivo study showed the anti-tumor activity of FSH33-53-IIKK was enhanced compared to that of IIKK only. FSH33-53-IIKK could inhibit the growth of tumor via apoptosis and autophagy pathways. In summary, combining the tumor marker-target peptide and anti-tumor peptide together may be an efficient way to search for better anti-tumor candidates.
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Affiliation(s)
- Runlin Yang
- 1. Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Ping Liu
- 2. School of Pharmaceutical Science, Zhengzhou University, Zhengzhou 450000, China
| | - Donghui Pan
- 1. Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Pengjun Zhang
- 2. School of Pharmaceutical Science, Zhengzhou University, Zhengzhou 450000, China
| | - Zhicheng Bai
- 3. The First School of Clinical Medicine, Nanjing Medical University, Nanjing 210029, China
| | - Yuping Xu
- 1. Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Lizhen Wang
- 1. Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Junjie Yan
- 1. Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Yongjun Yan
- 4. Department of Medical Physics, University of Wisconsin, Madison, WI 53705, USA
| | - Xingdang Liu
- 5. Department of Nuclear Medicine, Hua Shan Hospital, Fudan University, Shanghai 200040, China
| | - Min Yang
- 1. Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China.; 2. School of Pharmaceutical Science, Zhengzhou University, Zhengzhou 450000, China.; 3. The First School of Clinical Medicine, Nanjing Medical University, Nanjing 210029, China
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Richter S, Wuest M, Bergman CN, Krieger S, Rogers BE, Wuest F. Metabolically Stabilized (68)Ga-NOTA-Bombesin for PET Imaging of Prostate Cancer and Influence of Protease Inhibitor Phosphoramidon. Mol Pharm 2016; 13:1347-57. [PMID: 26973098 DOI: 10.1021/acs.molpharmaceut.5b00970] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptide receptor-based targeted molecular imaging and therapy of cancer is on the current forefront of nuclear medicine preclinical research and clinical practice. The frequent overexpression of gastrin-releasing peptide (GRP) receptors in prostate cancer stimulated the development of radiolabeled bombesin derivatives as high affinity peptide ligands for selective targeting of the GRP receptor. In this study, we have evaluated a novel (68)Ga-labeled bombesin derivative for PET imaging of prostate cancer in vivo. In addition, we were interested in testing the recently proposed "serve-and-protect" strategy to improve metabolic stability of radiolabeled peptides in vivo and to enhance tumor uptake. GRP receptor targeting peptides NOTA-BBN2 and (nat)Ga-NOTA-BBN2 demonstrated a characteristic antagonistic profile and high binding affinity toward the GRP receptor in PC3 cells (IC50 4.6-8.2 nM). Radiolabeled peptide (68)Ga-NOTA-BBN2 was obtained from NOTA-BBN2 in radiochemical yields greater than 62% (decay-corrected). Total synthesis time was 35 min, including purification using solid-phase extraction. (68)Ga-NOTA-BBN2 exhibited favorable resistance against metabolic degradation by peptidases in vivo within the investigated time frame of 60 min. Interestingly, metabolic stability was not further enhanced in the presence of protease inhibitor phosphoramidon. Dynamic PET studies showed high tumor uptake in both PC3- and LNCaP-bearing BALB/c nude mice (SUV5min > 0.6; SUV60min > 0.5). Radiotracer (68)Ga-NOTA-BBN2 represents a novel radiometal-based bombesin derivative suitable for GRP receptor targeting in PC3 and LNCaP mouse xenografts. Further increase of metabolic stability in vivo and enhanced tumor uptake were not observed upon administration of protease inhibitor phosphoramidon. This led to the conclusion that the recently proposed "serve-and-protect" strategy may not be valid for peptides exhibiting favorable intrinsic metabolic stability in vivo.
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Affiliation(s)
- Susan Richter
- Department of Oncology, University of Alberta, Cross Cancer Institute , Edmonton, Alberta T6G 2X4, Canada
| | - Melinda Wuest
- Department of Oncology, University of Alberta, Cross Cancer Institute , Edmonton, Alberta T6G 2X4, Canada
| | - Cody N Bergman
- Department of Oncology, University of Alberta, Cross Cancer Institute , Edmonton, Alberta T6G 2X4, Canada
| | - Stephanie Krieger
- Department of Radiation Oncology, Washington University School of Medicine , St. Louis, Missouri 63108, United States
| | - Buck E Rogers
- Department of Radiation Oncology, Washington University School of Medicine , St. Louis, Missouri 63108, United States
| | - Frank Wuest
- Department of Oncology, University of Alberta, Cross Cancer Institute , Edmonton, Alberta T6G 2X4, Canada
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Kaloudi A, Nock BA, Lymperis E, Valkema R, Krenning EP, de Jong M, Maina T. Impact of clinically tested NEP/ACE inhibitors on tumor uptake of [(111)In-DOTA]MG11-first estimates for clinical translation. EJNMMI Res 2016; 6:15. [PMID: 26882895 PMCID: PMC4755954 DOI: 10.1186/s13550-015-0158-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/28/2015] [Indexed: 12/23/2022] Open
Abstract
Background We have recently shown that treatment of mice with the neutral endopeptidase (NEP) inhibitor phosphoramidon (PA) improves the bioavailability and tumor uptake of biodegradable radiopeptides. For the truncated gastrin radiotracer [111In-DOTA]MG11 ([(DOTA)DGlu10]gastrin(10–17)), this method led to impressively high tumor-to-kidney ratios. Translation of this concept in the clinic requires the use of certified NEP inhibitors, such as thiorphan (TO) and its orally administered prodrug racecadotril (Race). Besides NEP, angiotensin-converting enzyme (ACE) has also been implicated in the catabolism of gastrin analogs. In the present study, we first compared the effects induced by NEP inhibition (using PA, TO, or Race) and/or by ACE inhibition (using lisinopril, Lis) on the biodistribution profile of [111In-DOTA]MG11 in mice. In addition, we compared the efficacy of PA and TO at different administered doses to enhance tumor uptake. Methods [111In-DOTA]MG11 was coinjected with (a) vehicle, (b) PA (300 μg), (c) TO (150 μg), (d) Lis (100 μg), (e) PA (300 μg) plus Lis (100 μg), or (f) 30–40 min after intraperitoneal (ip) injection of Race (3 mg) in SCID mice bearing AR42J xenografts. In addition, [111In-DOTA]MG11 was coinjected with vehicle, or with progressively increasing amounts of PA (3, 30, or 300 μg) or TO (1.5, 15, and 150 μg) in SCID mice bearing twin A431-CCK2R(+/−) tumors. In all above cases, biodistribution was conducted at 4 h postinjection (pi). Results During NEP inhibition, the uptake of [111In-DOTA]MG11 in the AR42J tumors impressively increased from 1.8 ± 1.0 % ID/g (controls) to 15.3 ± 4.7 % ID/g (PA) and 12.3 ± 3.6 % ID/g (TO), while with Race tumor values reached 6.8 ± 2.8 % ID/g. Conversely, Lis had no effect on tumor uptake and no additive effect when coinjected with PA. During the dose dependence study in mice, PA turned out to be more efficacious in enhancing tumor uptake of [111In-DOTA]MG11 in the CCK2R-positive tumors compared to equimolar amounts of TO. In all cases, renal accumulation remained low, resulting in notable increases of tumor-to-kidney ratios. Conclusions This study has confirmed NEP as the predominant degrading enzyme of [111In-DOTA]MG11 and ruled out the involvement of ACE in the in vivo catabolism of the radiotracer. NEP inhibition with the clinically tested NEP inhibitors TO and Race resulted in significant enhancement of tumor-to-kidney ratios vs. controls. However, compared with PA, TO and its prodrug Race induced less potent increases of tumor uptake, highlighting the significance of inhibitor type, administration route, and dose for implementing a first proof-of-principle study in human. Electronic supplementary material The online version of this article (doi:10.1186/s13550-015-0158-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aikaterini Kaloudi
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Ag. Paraskevi Attikis, GR-153 10, Athens, Greece.
| | - Berthold A Nock
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Ag. Paraskevi Attikis, GR-153 10, Athens, Greece.
| | - Emmanouil Lymperis
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Ag. Paraskevi Attikis, GR-153 10, Athens, Greece.
| | - Roelf Valkema
- Department of Nuclear Medicine, Erasmus MC, 3015 GD, Rotterdam, the Netherlands.
| | - Eric P Krenning
- Department of Nuclear Medicine, Erasmus MC, 3015 GD, Rotterdam, the Netherlands.
| | - Marion de Jong
- Department of Nuclear Medicine, Erasmus MC, 3015 GD, Rotterdam, the Netherlands. .,Department of Radiology, Erasmus MC, 3015 GD, Rotterdam, the Netherlands.
| | - Theodosia Maina
- Molecular Radiopharmacy, INRASTES, NCSR "Demokritos", Ag. Paraskevi Attikis, GR-153 10, Athens, Greece.
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