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Muthukumar S, Darden J, Crowley J, Witcher M, Kiser J. A Comparison of PET Tracers in Recurrent High-Grade Gliomas: A Systematic Review. Int J Mol Sci 2022; 24:ijms24010408. [PMID: 36613852 PMCID: PMC9820099 DOI: 10.3390/ijms24010408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022] Open
Abstract
Humans with high-grade gliomas have a poor prognosis, with a mean survival time of just 12-18 months for patients who undergo standard-of-care tumor resection and adjuvant therapy. Currently, surgery and chemoradiotherapy serve as standard treatments for this condition, yet these can be complicated by the tumor location, growth rate and recurrence. Currently, gadolinium-based, contrast-enhanced magnetic resonance imaging (CE-MRI) serves as the predominant imaging modality for recurrent high-grade gliomas, but it faces several drawbacks, including its inability to distinguish tumor recurrence from treatment-related changes and its failure to reveal the entirety of tumor burden (de novo or recurrent) due to limitations inherent to gadolinium contrast. As such, alternative imaging modalities that can address these limitations, including positron emission tomography (PET), are worth pursuing. To this end, the identification of PET-based markers for use in imaging of recurrent high-grade gliomas is paramount. This review will highlight several PET radiotracers that have been implemented in clinical practice and provide a comparison between them to assess the efficacy of these tracers.
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Affiliation(s)
| | - Jordan Darden
- Carilion Clinic Neurosurgery, Roanoke, VA 24016, USA
| | | | - Mark Witcher
- Carilion Clinic Neurosurgery, Roanoke, VA 24016, USA
| | - Jackson Kiser
- Carilion Clinic Radiology, Roanoke, VA 24016, USA
- Correspondence:
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Imaging Properties and Tumor Targeting of 68Ga-NeoBOMB1, a Gastrin-Releasing Peptide Receptor Antagonist, in GIST Patients. Biomedicines 2022; 10:biomedicines10112899. [PMID: 36428467 PMCID: PMC9687401 DOI: 10.3390/biomedicines10112899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/02/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Gastrin-releasing peptide receptors (GRPRs) are molecular imaging targets in multiple malignancies. Recently, NeoBOMB1, a 68Ga-labelled antagonist to GRPRs, was developed for PET. Here we report the outcome of a Phase I/IIa clinical trial (EudraCT 2016-002053-38) describing diagnostic properties and covariates influencing uptake of 68Ga-NeoBOMB1 in oligometastatic gastrointestinal stromal tumor (GIST) patients. Methods: Nine patients with advanced GIST using PET/CT (computed tomography) were included. After kit-based 68Ga-NeoBOMB1 preparation with a licensed 68Ge/68Ga generator, 3 MBq/kg body weight were injected intravenously. PET/CT included dynamic and static PET scans 5, 12 and 18 min and 1, 2, and 3−4 h post injection (first six patients) and static PET scans 2 and 3−4 h post injection (last three participants). Tumor targeting was assessed on a per-lesion and per-patient basis. Results: Six patients showed visible radiotracer uptake in at least one tumor lesion. Seventeen out of 37 tumor lesions exhibited significant 68Ga-NeoBOMB1 uptake (median SUVmax 11.8 [range 2.8−51.1] 2 h p.i. and 13.2 [range 2.5−53.8] 3−4 h p.i) and improved lesion-to-background contrast over time. Five lesions (13.5%) were identified only by 68Ga-NeoBOMB1-PET, with no correlation on contrast-enhanced CT. Three patients showed no radiotracer accumulation in any lesions. Tracer uptake correlated with male sex (p < 0.0001), higher body mass index (p = 0.007), and non-necrotic lesion appearance (p = 0.018). There was no association with whole-lesion contrast enhancement, hepatic localization, mutational status, or disease duration. Conclusions: 68Ga-NeoBOMB1-PET exhibits variable tumor uptake in advanced-stage GIST patients, correlating with lesion vitality based on CT contrast uptake, opening the possibility of a theragnostic approach in selected cases.
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Mukai H, Watanabe Y. Review: PET imaging with macro- and middle-sized molecular probes. Nucl Med Biol 2021; 92:156-170. [PMID: 32660789 DOI: 10.1016/j.nucmedbio.2020.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/22/2020] [Accepted: 06/22/2020] [Indexed: 12/16/2022]
Abstract
Recent progress in radiolabeling of macro- and middle-sized molecular probes has been extending possibilities to use PET molecular imaging for dynamic application to drug development and therapeutic evaluation. Theranostics concept also accelerated the use of macro- and middle-sized molecular probes for sharpening the contrast of proper target recognition even the cellular types/subtypes and proper selection of the patients who should be treated by the same molecules recognition. Here, brief summary of the present status of immuno-PET, and then further development of advanced technologies related to immuno-PET, peptidic PET probes, and nucleic acids PET probes are described.
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Affiliation(s)
- Hidefumi Mukai
- Laboratory for Molecular Delivery and Imaging Technology, RIKEN Center for Biosystems Dynamics Research, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
| | - Yasuyoshi Watanabe
- Laboratory for Pathophysiological and Health Science, RIKEN Center for Biosystems Dynamics Research, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
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Moody TW, Lee L, Ramos-Alvarez I, Iordanskaia T, Mantey SA, Jensen RT. Bombesin Receptor Family Activation and CNS/Neural Tumors: Review of Evidence Supporting Possible Role for Novel Targeted Therapy. Front Endocrinol (Lausanne) 2021; 12:728088. [PMID: 34539578 PMCID: PMC8441013 DOI: 10.3389/fendo.2021.728088] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 08/02/2021] [Indexed: 12/13/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are increasingly being considered as possible therapeutic targets in cancers. Activation of GPCR on tumors can have prominent growth effects, and GPCRs are frequently over-/ectopically expressed on tumors and thus can be used for targeted therapy. CNS/neural tumors are receiving increasing attention using this approach. Gliomas are the most frequent primary malignant brain/CNS tumor with glioblastoma having a 10-year survival <1%; neuroblastomas are the most common extracranial solid tumor in children with long-term survival<40%, and medulloblastomas are less common, but one subgroup has a 5-year survival <60%. Thus, there is an increased need for more effective treatments of these tumors. The Bombesin-receptor family (BnRs) is one of the GPCRs that are most frequently over/ectopically expressed by common tumors and is receiving particular attention as a possible therapeutic target in several tumors, particularly in prostate, breast, and lung cancer. We review in this paper evidence suggesting why a similar approach in some CNS/neural tumors (gliomas, neuroblastomas, medulloblastomas) should also be considered.
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Affiliation(s)
- Terry W. Moody
- Department of Health and Human Services, National Cancer Institute, Center for Cancer Training, Office of the Director, Bethesda, MD, United States
| | - Lingaku Lee
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
- Department of Gastroenterology, National Hospital Organization Kyushu Cancer Center, Fukuoka, Japan
| | - Irene Ramos-Alvarez
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Tatiana Iordanskaia
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Samuel A. Mantey
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Robert T. Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Robert T. Jensen,
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Dimitrakopoulou-Strauss A, Pan L, Sachpekidis C. Kinetic modeling and parametric imaging with dynamic PET for oncological applications: general considerations, current clinical applications, and future perspectives. Eur J Nucl Med Mol Imaging 2020; 48:21-39. [PMID: 32430580 PMCID: PMC7835173 DOI: 10.1007/s00259-020-04843-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/27/2020] [Indexed: 02/07/2023]
Abstract
Dynamic PET (dPET) studies have been used until now primarily within research purposes. Although it is generally accepted that the information provided by dPET is superior to that of conventional static PET acquisitions acquired usually 60 min post injection of the radiotracer, the duration of dynamic protocols, the limited axial field of view (FOV) of current generation clinical PET systems covering a relatively small axial extent of the human body for a dynamic measurement, and the complexity of data evaluation have hampered its implementation into clinical routine. However, the development of new-generation PET/CT scanners with an extended FOV as well as of more sophisticated evaluation software packages that offer better segmentation algorithms, automatic retrieval of the arterial input function, and automatic calculation of parametric imaging, in combination with dedicated shorter dynamic protocols, will facilitate the wider use of dPET. This is expected to aid in oncological diagnostics and therapy assessment. The aim of this review is to present some general considerations about dPET analysis in oncology by means of kinetic modeling, based on compartmental and noncompartmental approaches, and parametric imaging. Moreover, the current clinical applications and future perspectives of the modality are outlined.
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Affiliation(s)
- Antonia Dimitrakopoulou-Strauss
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
| | - Leyun Pan
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Christos Sachpekidis
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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Gruber L, Jiménez-Franco LD, Decristoforo C, Uprimny C, Glatting G, Hohenberger P, Schoenberg SO, Reindl W, Orlandi F, Mariani M, Jaschke W, Virgolini I. MITIGATE-NeoBOMB1, a Phase I/IIa Study to Evaluate Safety, Pharmacokinetics, and Preliminary Imaging of 68Ga-NeoBOMB1, a Gastrin-Releasing Peptide Receptor Antagonist, in GIST Patients. J Nucl Med 2020; 61:1749-1755. [PMID: 32332143 DOI: 10.2967/jnumed.119.238808] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/28/2020] [Indexed: 12/13/2022] Open
Abstract
Gastrin-releasing peptide receptors (GRPRs) are potential molecular imaging targets in a variety of tumors. Recently, a 68Ga-labeled antagonist to GRPRs, NeoBOMB1, was developed for PET. We report on the outcome of a phase I/IIa clinical trial (EudraCT 2016-002053-38) within the EU-FP7 project Closed-loop Molecular Environment for Minimally Invasive Treatment of Patients with Metastatic Gastrointestinal Stromal Tumors ('MITIGATE') (grant agreement no. 602306) in patients with oligometastatic gastrointestinal stromal tumors (GIST). Methods: The main objectives were evaluation of safety, biodistribution, dosimetry, and preliminary tumor targeting of 68Ga-NeoBOMB1 in patients with advanced tyrosine-kinase inhibitors-treated GIST using PET/CT. Six patients with histologically confirmed GIST and unresectable primary lesion or metastases undergoing an extended protocol for detailed pharmacokinetic analysis were included. 68Ga-NeoBOMB1 was prepared using a kit procedure with a licensed 68Ge/68Ga generator. 68Ga-NeoBOMB1 (3 MBq/kg of body weight) was injected intravenously, and safety parameters were assessed. PET/CT included dynamic imaging at 5, 11, and 19 min as well as static imaging at 1, 2, and 3-4 h after injection for dosimetry calculations. Venous blood samples and urine were collected for pharmacokinetic analysis. Tumor targeting was assessed on a per-lesion and per-patient basis. Results: 68Ga-NeoBOMB1 (50 μg) was prepared with high radiochemical purity (yield > 97%). Patients received 174 ± 28 MBq of the radiotracer, which was well tolerated in all patients over a follow-up period of 4 wk. Dosimetry calculations revealed a mean effective dose of 0.029 ± 0.06 mSv/MBq, with the highest organ dose to the pancreas (0.274 ± 0.099 mSv/MBq). Mean plasma half-life was 27.3 min with primarily renal clearance (mean 25.7% ± 5.4% of injected dose 4 h after injection). Plasma metabolite analyses revealed high stability; metabolites were detected only in the urine. In 3 patients, a significant uptake with increasing maximum SUVs (SUVmax at 2 h after injection: 4.3-25.9) over time was found in tumor lesions. Conclusion: This phase I/IIa study provides safety data for 68Ga-NeoBOMB1, a promising radiopharmaceutical for targeting GRPR-expressing tumors. Safety profiles and pharmacokinetics are suitable for PET imaging, and absorbed dose estimates are comparable to those of other 68Ga-labeled radiopharmaceuticals used in clinical routine.
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Affiliation(s)
- Leonhard Gruber
- Department of Radiology, Medical University Innsbruck, Innsbruck, Austria
| | - Luis David Jiménez-Franco
- Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Christian Uprimny
- Department of Nuclear Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Gerhard Glatting
- Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, Ulm, Germany
| | - Peter Hohenberger
- Division of Surgical Oncology and Thoracic Surgery, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Stefan O Schoenberg
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Wolfgang Reindl
- Klinikum Mannheim II, Medizinische Klinik, Mannheim, Germany; and
| | - Francesca Orlandi
- Advanced Accelerator Applications, a Novartis Company, Colleretto Giacosa TO, Italy
| | - Maurizio Mariani
- Advanced Accelerator Applications, a Novartis Company, Colleretto Giacosa TO, Italy
| | - Werner Jaschke
- Department of Radiology, Medical University Innsbruck, Innsbruck, Austria
| | - Irene Virgolini
- Department of Nuclear Medicine, Medical University Innsbruck, Innsbruck, Austria
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Rangger C, Haubner R. Radiolabelled Peptides for Positron Emission Tomography and Endoradiotherapy in Oncology. Pharmaceuticals (Basel) 2020; 13:E22. [PMID: 32019275 PMCID: PMC7169460 DOI: 10.3390/ph13020022] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 02/07/2023] Open
Abstract
This review deals with the development of peptide-based radiopharmaceuticals for the use with positron emission tomography and peptide receptor radiotherapy. It discusses the pros and cons of this class of radiopharmaceuticals as well as the different labelling strategies, and summarises approaches to optimise metabolic stability. Additionally, it presents different target structures and addresses corresponding tracers, which are already used in clinical routine or are being investigated in clinical trials.
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Affiliation(s)
| | - Roland Haubner
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria;
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Tang D, Li J, Nickels ML, Huang G, Cohen AS, Manning HC. Preclinical Evaluation of a Novel TSPO PET Ligand 2-(7-Butyl-2-(4-(2-[ 18F]Fluoroethoxy)phenyl)-5-Methylpyrazolo[1,5-a]Pyrimidin-3-yl)-N,N-Diethylacetamide ( 18F-VUIIS1018A) to Image Glioma. Mol Imaging Biol 2019; 21:113-121. [PMID: 29869061 DOI: 10.1007/s11307-018-1198-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE There is an urgent need for the development of novel positron emission tomography (PET) tracers for glioma imaging. In this study, we developed a novel PET probe ([18F]VUIIS1018A) by targeting translocator protein (TSPO), an imaging biomarker for glioma. The purpose of this preclinical study was to evaluate this novel TSPO probe for glioma imaging. PROCEDURES In this study, we synthesized [19F]VUIIS1018A and the precursor for radiosynthesis of [18F]VUIIS1018A. TSPO binding affinity was confirmed using a radioligand competitive binding assay in C6 glioma cell lysate. Further, dynamic imaging studies were performed in rats using a microPET system. These studies include displacement and blocking studies for ligand reversibility and specificity evaluation, and compartment modeling of PET data for pharmacokinetic parameter measurement using metabolite-corrected arterial input functions and PMOD. RESULTS Compared to previously reported TSPO tracers including [18F]VUIIS1008 and [18F]DPA-714, the novel tracer [18F]VUIIS1018A demonstrated higher binding affinity and BPND. Pretreatment with the cold analog [19F]VUIIS1018A could partially block tumor accumulation of this novel tracer. Further, compartment modeling of this novel tracer also exhibited a greater tumor-to-background ratio, a higher tumor binding potential and a lower brain binding potential when compared with other TSPO probes, such as [18F]DPA-714 and [18F]VUIIS1008. CONCLUSIONS These studies illustrate that [18F]VUIIS1018A can serve as a promising TSPO PET tracer for glioma imaging and potentially imaging of other solid tumors.
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Affiliation(s)
- Dewei Tang
- Center for Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, China.,Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pujian Road, Pudong New District, Shanghai, 200127, China
| | - Jun Li
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael L Nickels
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gang Huang
- Center for Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, China.,Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pujian Road, Pudong New District, Shanghai, 200127, China
| | - Allison S Cohen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA
| | - H Charles Manning
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA. .,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA. .,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA. .,Program in Chemical and Physical Biology, Vanderbilt University Medical Center, Nashville, TN, USA. .,Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA. .,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA. .,Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, TN, USA.
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Röhrich M, Huang K, Schrimpf D, Albert NL, Hielscher T, von Deimling A, Schüller U, Dimitrakopoulou-Strauss A, Haberkorn U. Integrated analysis of dynamic FET PET/CT parameters, histology, and methylation profiling of 44 gliomas. Eur J Nucl Med Mol Imaging 2018; 45:1573-1584. [DOI: 10.1007/s00259-018-4009-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/05/2018] [Indexed: 01/24/2023]
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Jackson IM, Scott PJ, Thompson S. Clinical Applications of Radiolabeled Peptides for PET. Semin Nucl Med 2017; 47:493-523. [DOI: 10.1053/j.semnuclmed.2017.05.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Development of Drugs and Technology for Radiation Theragnosis. NUCLEAR ENGINEERING AND TECHNOLOGY 2016. [DOI: 10.1016/j.net.2016.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Moreno P, Ramos-Álvarez I, Moody TW, Jensen RT. Bombesin related peptides/receptors and their promising therapeutic roles in cancer imaging, targeting and treatment. Expert Opin Ther Targets 2016; 20:1055-73. [PMID: 26981612 DOI: 10.1517/14728222.2016.1164694] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Despite remarkable advances in tumor treatment, many patients still die from common tumors (breast, prostate, lung, CNS, colon, and pancreas), and thus, new approaches are needed. Many of these tumors synthesize bombesin (Bn)-related peptides and over-express their receptors (BnRs), hence functioning as autocrine-growth-factors. Recent studies support the conclusion that Bn-peptides/BnRs are well-positioned for numerous novel antitumor treatments, including interrupting autocrine-growth and the use of over-expressed receptors for imaging and targeting cytotoxic-compounds, either by direct-coupling or combined with nanoparticle-technology. AREAS COVERED The unique ability of common neoplasms to synthesize, secrete, and show a growth/proliferative/differentiating response due to BnR over-expression, is reviewed, both in general and with regard to the most frequently investigated neoplasms (breast, prostate, lung, and CNS). Particular attention is paid to advances in the recent years. Also considered are the possible therapeutic approaches to the growth/differentiation effect of Bn-peptides, as well as the therapeutic implication of the frequent BnR over-expression for tumor-imaging and/or targeted-delivery. EXPERT OPINION Given that Bn-related-peptides/BnRs are so frequently ectopically-expressed by common tumors, which are often malignant and become refractory to conventional treatments, therapeutic interventions using novel approaches to Bn-peptides and receptors are being explored. Of particular interest is the potential of reproducing with BnRs in common tumors the recent success of utilizing overexpression of somatostatin-receptors by neuroendocrine-tumors to provide the most sensitive imaging methods and targeted delivery of cytotoxic-compounds.
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Affiliation(s)
- Paola Moreno
- a Digestive Diseases Branch, Cell Biology Section, NIDDK , National Institutes of Health , Bethesda , MD , USA
| | - Irene Ramos-Álvarez
- a Digestive Diseases Branch, Cell Biology Section, NIDDK , National Institutes of Health , Bethesda , MD , USA
| | - Terry W Moody
- b Center for Cancer Research, Office of the Director , NCI, National Institutes of Health , Bethesda , MD , USA
| | - Robert T Jensen
- a Digestive Diseases Branch, Cell Biology Section, NIDDK , National Institutes of Health , Bethesda , MD , USA
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Sachpekidis C, Eder M, Kopka K, Mier W, Hadaschik BA, Haberkorn U, Dimitrakopoulou-Strauss A. 68Ga-PSMA-11 dynamic PET/CT imaging in biochemical relapse of prostate cancer. Eur J Nucl Med Mol Imaging 2016; 43:1288-99. [DOI: 10.1007/s00259-015-3302-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/22/2015] [Indexed: 02/07/2023]
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Ma MT, Cullinane C, Waldeck K, Roselt P, Hicks RJ, Blower PJ. Rapid kit-based (68)Ga-labelling and PET imaging with THP-Tyr(3)-octreotate: a preliminary comparison with DOTA-Tyr(3)-octreotate. EJNMMI Res 2015; 5:52. [PMID: 26452495 PMCID: PMC4600075 DOI: 10.1186/s13550-015-0131-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 09/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ge/(68)Ga generators provide an inexpensive source of a PET isotope to hospitals without cyclotron facilities. The development of new (68)Ga-based molecular imaging agents and subsequent clinical translation would be greatly facilitated by simplification of radiochemical syntheses. We report the properties of a tris(hydroxypyridinone) conjugate of the SSTR2-targeted peptide, Tyr(3)-octreotate (TATE), and compare the (68)Ga-labelling and biodistribution of [(68)Ga(THP-TATE)] with the clinical radiopharmaceutical [(68)Ga(DOTATATE)]. METHODS A tris(hydroxypyridinone) with a pendant isothiocyanate group was conjugated to the primary amine terminus of H2N-PEG2-Lys(iv-Dde)(5)-TATE, and the resulting conjugate was deprotected to provide THP-TATE. THP-TATE was radiolabelled with (68)Ga(3+) from a (68)Ge/(68)Ga generator. In vitro uptake was assessed in SSTR2-positive 427-7 cells and SSTR2-negative 427 (parental) cells. Biodistribution of [(68)Ga(THP-TATE)] was compared with that of [(68)Ga(DOTATATE)] in Balb/c nude mice bearing SSTR2-positive AR42J tumours. PET scans were obtained 1 h post-injection, after which animals were euthanised and tissues/organs harvested and counted. RESULTS [(68)Ga(THP-TATE)] was radiolabelled and formulated rapidly in <2 min, in ≥95 % radiochemical yield at pH 5-6.5 and specific activities of 60-80 MBq nmol(-1) at ambient temperature. [(68)Ga(THP-TATE)] was rapidly internalised into SSTR2-positive cells, but not SSTR2-negative cells, and receptor binding and internalisation were specific. Animals administered [(68)Ga(THP-TATE)] demonstrated comparable SSTR2-positive tumour activity (11.5 ± 0.6 %ID g(-1)) compared to animals administered [(68)Ga(DOTATATE)] (14.4 ± 0.8 %ID g(-1)). Co-administration of unconjugated Tyr(3)-octreotate effectively blocked tumour accumulation of [(68)Ga(THP-TATE)] (2.7 ± 0.6 %ID g(-1)). Blood clearance of [(68)Ga(THP-TATE)] was rapid and excretion was predominantly renal, although compared to [(68)Ga(DOTATATE)], [(68)Ga(THP-TATE)] exhibited comparatively longer kidney retention. CONCLUSIONS Radiochemical synthesis of [(68)Ga(THP-TATE)] is significantly faster, proceeds under milder conditions, and requires less manipulation than that of [(68)Ga(DOTATATE)]. A (68)Ga-labelled tris(hydroxypyridinone) conjugate of Tyr(3)-octreotate demonstrates specificity and targeting affinity for SSTR2 receptors, with comparable in vivo targeting affinity to the clinical PET tracer, [(68)Ga(DOTATATE)]. Thus, peptide conjugates based on tris(hydroxypyridinones) are conducive to translation to kit-based preparation of PET tracers, enabling the expansion and adoption of (68)Ga PET in hospitals and imaging centres without the need for costly automated synthesis modules.
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Affiliation(s)
- Michelle T Ma
- Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK.
| | - Carleen Cullinane
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Kelly Waldeck
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Peter Roselt
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Rodney J Hicks
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Philip J Blower
- Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK
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15
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Ramos-Álvarez I, Moreno P, Mantey SA, Nakamura T, Nuche-Berenguer B, Moody TW, Coy DH, Jensen RT. Insights into bombesin receptors and ligands: Highlighting recent advances. Peptides 2015; 72:128-44. [PMID: 25976083 PMCID: PMC4641779 DOI: 10.1016/j.peptides.2015.04.026] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 12/22/2022]
Abstract
This following article is written for Prof. Abba Kastin's Festschrift, to add to the tribute to his important role in the advancement of the role of peptides in physiological, as well as pathophysiological processes. There have been many advances during the 35 years of his prominent role in the Peptide field, not only as editor of the journal Peptides, but also as a scientific investigator and editor of two volumes of the Handbook of Biological Active Peptides [146,147]. Similar to the advances with many different peptides, during this 35 year period, there have been much progress made in the understanding of the pharmacology, cell biology and the role of (bombesin) Bn receptors and their ligands in various disease states, since the original isolation of bombesin from skin of the European frog Bombina bombina in 1970 [76]. This paper will briefly review some of these advances over the time period of Prof. Kastin 35 years in the peptide field concentrating on the advances since 2007 when many of the results from earlier studies were summarized [128,129]. It is appropriate to do this because there have been 280 articles published in Peptides during this time on bombesin-related peptides and it accounts for almost 5% of all publications. Furthermore, 22 Bn publications we have been involved in have been published in either Peptides [14,39,55,58,81,92,93,119,152,216,225,226,231,280,302,309,355,361,362] or in Prof. Kastin's Handbook of Biological Active Peptides [137,138,331].
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Affiliation(s)
- Irene Ramos-Álvarez
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892-1804, United States
| | - Paola Moreno
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892-1804, United States
| | - Samuel A Mantey
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892-1804, United States
| | - Taichi Nakamura
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892-1804, United States
| | - Bernardo Nuche-Berenguer
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892-1804, United States
| | - Terry W Moody
- Center for Cancer Research, Office of the Director, NCI, National Institutes of Health, Bethesda, MD 20892-1804, United States
| | - David H Coy
- Peptide Research Laboratory, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112-2699, United States
| | - Robert T Jensen
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892-1804, United States.
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16
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Tichauer KM, Wang Y, Pogue BW, Liu JTC. Quantitative in vivo cell-surface receptor imaging in oncology: kinetic modeling and paired-agent principles from nuclear medicine and optical imaging. Phys Med Biol 2015; 60:R239-69. [PMID: 26134619 PMCID: PMC4522156 DOI: 10.1088/0031-9155/60/14/r239] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The development of methods to accurately quantify cell-surface receptors in living tissues would have a seminal impact in oncology. For example, accurate measures of receptor density in vivo could enhance early detection or surgical resection of tumors via protein-based contrast, allowing removal of cancer with high phenotype specificity. Alternatively, accurate receptor expression estimation could be used as a biomarker to guide patient-specific clinical oncology targeting of the same molecular pathway. Unfortunately, conventional molecular contrast-based imaging approaches are not well adapted to accurately estimating the nanomolar-level cell-surface receptor concentrations in tumors, as most images are dominated by nonspecific sources of contrast such as high vascular permeability and lymphatic inhibition. This article reviews approaches for overcoming these limitations based upon tracer kinetic modeling and the use of emerging protocols to estimate binding potential and the related receptor concentration. Methods such as using single time point imaging or a reference-tissue approach tend to have low accuracy in tumors, whereas paired-agent methods or advanced kinetic analyses are more promising to eliminate the dominance of interstitial space in the signals. Nuclear medicine and optical molecular imaging are the primary modalities used, as they have the nanomolar level sensitivity needed to quantify cell-surface receptor concentrations present in tissue, although each likely has a different clinical niche.
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Affiliation(s)
- Kenneth M Tichauer
- Biomedical Engineering, Illinois Institute of Technology, Chicago IL 60616, USA
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17
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Pandey U, Mukherjee A, Jindal A, Gamre N, Korde A, Ram R, Sarma HD, Dash A. Preparation and evaluation of a single vial AMBA kit for 68Ga labeling with potential for imaging of GRP receptor-positive cancers. J Radioanal Nucl Chem 2015. [DOI: 10.1007/s10967-015-4290-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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18
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Tang D, Nickels ML, Tantawy MN, Buck JR, Manning HC. Preclinical imaging evaluation of novel TSPO-PET ligand 2-(5,7-Diethyl-2-(4-(2-[(18)F]fluoroethoxy)phenyl)pyrazolo[1,5-a]pyrimidin-3-yl)-N,N-diethylacetamide ([ (18)F]VUIIS1008) in glioma. Mol Imaging Biol 2014; 16:813-20. [PMID: 24845529 PMCID: PMC4372299 DOI: 10.1007/s11307-014-0743-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Translocator protein (TSPO) concentrations are elevated in glioma, suggesting a role for TSPO positron emission tomography (PET) imaging in this setting. In preclinical PET studies, we evaluated a novel, high-affinity TSPO PET ligand, [(18)F]VUIIS1008, in healthy mice and glioma-bearing rats. PROCEDURES Dynamic PET data were acquired simultaneously with [(18)F]VUIIS1008 injection, with binding reversibility and specificity evaluated in vivo by non-radioactive ligand displacement or blocking. Compartmental analysis of PET data was performed using metabolite-corrected arterial input functions. Imaging was validated with histology and immunohistochemistry. RESULTS [(18)F]VUIIS1008 exhibited rapid uptake in TSPO-rich organs. PET ligand uptake was displaceable with non-radioactive VUIIS1008 or PBR06 in mice. Tumor accumulation of [(18)F]VUIIS1008 was blocked by pretreatment with VUIIS1008 in rats. [(18)F]VUIIS1008 exhibited improved tumor-to-background ratio and higher binding potential in tumors compared to a structurally similar pyrazolopyrimidine TSPO ligand, [(18)F]DPA-714. CONCLUSIONS The PET ligand [(18)F]VUIIS1008 exhibits promising characteristics as a tracer for imaging glioma. Further translational studies appear warranted.
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Affiliation(s)
- Dewei Tang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Michael L. Nickels
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - M. Noor Tantawy
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Jason R. Buck
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - H. Charles Manning
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Program in Chemical and Physical Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232
- Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee 37232
- Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
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Körner M, Waser B, Rehmann R, Reubi JC. Early over-expression of GRP receptors in prostatic carcinogenesis. Prostate 2014; 74:217-24. [PMID: 24150752 DOI: 10.1002/pros.22743] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/18/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND The GRP receptor shows high over-expression in prostatic adenocarcinoma and high grade PIN, but low expression in normal prostate glands. This represents the molecular basis for GRP receptor imaging of prostate cancer with radioactive compounds. However, a focal, high density GRP receptor expression can be observed in hitherto uncharacterized prostate glands. METHODS GRP receptors were quantitatively measured with in vitro receptor autoradiography using ¹²⁵I-Tyr⁴ -bombesin in samples from 115 prostates. On successive tissue sections, ¹²⁵I-Tyr⁴ -bombesin autoradiography was compared with H&E staining and MIB-1 and 34βE12 immunohistochemistry. RESULTS On one hand, it was confirmed that GRP receptors were expressed in adenocarcinoma and high grade PIN in high density and high incidence (77% and 73%, respectively), but in normal prostate glands in low density and low frequency (18%). On the other hand, a novel and intriguing observation was the existence of focal non-invasive prostate glands with high GRP receptor density, characterized by low grade nuclear atypia and increased proliferation, compatible with lower grade PIN. There was a significant GRP receptor density gradient (P ≤ 0.005), increasing from normal prostate glands (mean relative optical density, ROD, of ¹²⁵I-Tyr⁴ -bombesin binding: 0.17) over atypical glands without increased MIB-1 labeling (0.28) and atypical glands with increased MIB-1 expression (0.44) to high grade PIN and adenocarcinoma (0.64 and 0.58, respectively). CONCLUSIONS GRP receptor over-expression may be a novel, specific marker of early prostatic neoplastic transformation, arising in low grade PIN, and progressively increasing during malignant progression. This should be considered when interpreting in vivo GRP receptor imaging in males.
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Affiliation(s)
- Meike Körner
- Division of Cell Biology and Experimental Cancer Research, Institute of Pathology of the University of Berne, Berne, Switzerland
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20
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Velikyan I. Prospective of ⁶⁸Ga-radiopharmaceutical development. Theranostics 2013; 4:47-80. [PMID: 24396515 PMCID: PMC3881227 DOI: 10.7150/thno.7447] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 10/01/2013] [Indexed: 01/29/2023] Open
Abstract
Positron Emission Tomography (PET) experienced accelerated development and has become an established method for medical research and clinical routine diagnostics on patient individualized basis. Development and availability of new radiopharmaceuticals specific for particular diseases is one of the driving forces of the expansion of clinical PET. The future development of the ⁶⁸Ga-radiopharmaceuticals must be put in the context of several aspects such as role of PET in nuclear medicine, unmet medical needs, identification of new biomarkers, targets and corresponding ligands, production and availability of ⁶⁸Ga, automation of the radiopharmaceutical production, progress of positron emission tomography technologies and image analysis methodologies for improved quantitation accuracy, PET radiopharmaceutical regulations as well as advances in radiopharmaceutical chemistry. The review presents the prospects of the ⁶⁸Ga-based radiopharmaceutical development on the basis of the current status of these aspects as well as wide range and variety of imaging agents.
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Affiliation(s)
- Irina Velikyan
- 1. Preclinical PET Platform, Department of Medicinal Chemistry, Uppsala University, SE-75183 Uppsala, Sweden
- 2. PET-Centre, Centre for Medical Imaging, Uppsala University Hospital, SE-75185, Uppsala, Sweden
- 3. Department of Radiology, Oncology, and Radiation Science, Uppsala University, SE-75285 Uppsala, Sweden
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21
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Fani M, Maecke HR. Radiopharmaceutical development of radiolabelled peptides. Eur J Nucl Med Mol Imaging 2012; 39 Suppl 1:S11-30. [PMID: 22388624 DOI: 10.1007/s00259-011-2001-z] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Receptor targeting with radiolabelled peptides has become very important in nuclear medicine and oncology in the past few years. The overexpression of many peptide receptors in numerous cancers, compared to their relatively low density in physiological organs, represents the molecular basis for in vivo imaging and targeted radionuclide therapy with radiolabelled peptide-based probes. The prototypes are analogs of somatostatin which are routinely used in the clinic. More recent developments include somatostatin analogs with a broader receptor subtype profile or with antagonistic properties. Many other peptide families such as bombesin, cholecystokinin/gastrin, glucagon-like peptide-1 (GLP-1)/exendin, arginine-glycine-aspartic acid (RGD) etc. have been explored during the last few years and quite a number of potential radiolabelled probes have been derived from them. On the other hand, a variety of strategies and optimized protocols for efficient labelling of peptides with clinically relevant radionuclides such as (99m)Tc, M(3+) radiometals ((111)In, (86/90)Y, (177)Lu, (67/68)Ga), (64/67)Cu, (18)F or radioisotopes of iodine have been developed. The labelling approaches include direct labelling, the use of bifunctional chelators or prosthetic groups. The choice of the labelling approach is driven by the nature and the chemical properties of the radionuclide. Additionally, chemical strategies, including modification of the amino acid sequence and introduction of linkers/spacers with different characteristics, have been explored for the improvement of the overall performance of the radiopeptides, e.g. metabolic stability and pharmacokinetics. Herein, we discuss the development of peptides as radiopharmaceuticals starting from the choice of the labelling method and the conditions to the design and optimization of the peptide probe, as well as some recent developments, focusing on a selected list of peptide families, including somatostatin, bombesin, cholecystokinin/gastrin, GLP-1/exendin and RGD.
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Affiliation(s)
- Melpomeni Fani
- Department of Nuclear Medicine, University Hospital Freiburg, Hugstetterstrasse 55, 79106 Freiburg, Germany.
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22
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Cheng C, Pan L, Dimitrakopoulou-Strauss A, Schäfer M, Wängler C, Wängler B, Haberkorn U, Strauss LG. Comparison between 68Ga-bombesin (68Ga-BZH3) and the cRGD tetramer 68Ga-RGD4 studies in an experimental nude rat model with a neuroendocrine pancreatic tumor cell line. EJNMMI Res 2011; 1:34. [PMID: 22214362 PMCID: PMC3292467 DOI: 10.1186/2191-219x-1-34] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 12/13/2011] [Indexed: 11/10/2022] Open
Abstract
Objectives Receptor scintigraphy gains more interest for diagnosis and treatment of tumors, in particular for neuroendocrine tumors (NET). We used a pan-Bombesin analog, the peptide DOTA-PEG2-[D-tyr6, β-Ala11, Thi13, Nle14] BN(6-14) amide (BZH3). BZH3 binds to at least three receptor subtypes: the BB1 (Neuromedin B), BB2 (Gastrin-releasing peptide, GRP), and BB3. Imaging of ανβ3 integrin expression playing an important role in angiogenesis and metastasis was accomplished with a 68Ga-RGD tetramer. The purpose of this study was to investigate the kinetics and to compare both tracers in an experimental NET cell line. Methods This study comprised nine nude rats inoculated with the pancreatic tumor cell line AR42J. Dynamic positron emission tomography (PET) scans using 68Ga-BZH3 and 68Ga-RGD tetramer were performed (68Ga-RGD tetramer: n = 4, 68Ga-BZH3: n = 5). Standardized uptake values (SUVs) were calculated, and a two-tissue compartmental learning-machine model (calculation of K1 - k4 vessel density (VB) and receptor binding potential (RBP)) as well as a non-compartmental model based on the fractal dimension was used for quantitative analysis of both tracers. Multivariate analysis was used to evaluate the kinetic data. Results The PET kinetic parameters showed significant differences when individual parameters were compared between groups. Significant differences were found in FD, VB, K1, and RBP (p = 0.0275, 0.05, 0.05, and 0.0275 respectively). The 56- to 60-min SUV for 68Ga-BZH3, with a range of 0.86 to 1.29 (median, 1.19) was higher than the corresponding value for the 68Ga-RGD tetramer, with a range of 0.78 to 1.31 (median, 0.99). Furthermore, FD, VB, K1, and RBP for 68Ga-BZH3 were generally higher than the corresponding values for the 68Ga-RGD tetramer, whereas k3 was slightly higher for 68Ga-RGD tetramer. Conclusions As a parameter that reflects receptor binding, the increase of K1 for 68Ga-BZH3 indicated higher expression of bombesin receptors than that of the ανβ3 integrin in neuroendocrine tumors. 68Ga-BZH3 seems better suited for diagnosis of NETs owing to higher global tracer uptake.
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Affiliation(s)
- Caixia Cheng
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg, Germany.
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23
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Ambrosini V, Fani M, Fanti S, Forrer F, Maecke HR. Radiopeptide Imaging and Therapy in Europe. J Nucl Med 2011; 52 Suppl 2:42S-55S. [DOI: 10.2967/jnumed.110.085753] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Patient-Specific Method of Generating Parametric Maps of Patlak K(i) without Blood Sampling or Metabolite Correction: A Feasibility Study. INTERNATIONAL JOURNAL OF MOLECULAR IMAGING 2011; 2011:185083. [PMID: 21912742 PMCID: PMC3168784 DOI: 10.1155/2011/185083] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Accepted: 06/23/2011] [Indexed: 11/18/2022]
Abstract
Currently, kinetic analyses using dynamic positron emission tomography (PET) experience very limited use despite their potential for improving quantitative accuracy in several clinical and research applications. For targeted volume applications, such as radiation treatment planning, treatment monitoring, and cerebral metabolic studies, the key to implementation of these methods is the determination of an arterial input function, which can include time-consuming analysis of blood samples for metabolite correction. Targeted kinetic applications would become practical for the clinic if blood sampling and metabolite correction could be avoided. To this end, we developed a novel method (Patlak-P) of generating parametric maps that is identical to Patlak K(i) (within a global scalar multiple) but does not require the determination of the arterial input function or metabolite correction. In this initial study, we show that Patlak-P (a) mimics Patlak K(i) images in terms of visual assessment and target-to-background (TB) ratios of regions of elevated uptake, (b) has higher visual contrast and (generally) better image quality than SUV, and (c) may have an important role in improving radiotherapy planning, therapy monitoring, and neurometabolism studies.
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Strauss LG, Koczan D, Seiz M, Tuettenberg J, Schmieder K, Pan L, Cheng C, Dimitrakopoulou-Strauss A. Correlation of the Ga-68-Bombesin Analog Ga-68-BZH3 with Receptors Expression in Gliomas as Measured by Quantitative Dynamic Positron Emission Tomography (dPET) and Gene Arrays. Mol Imaging Biol 2011; 14:376-83. [DOI: 10.1007/s11307-011-0508-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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