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Wodtke R, Laube M, Hauser S, Meister S, Ludwig FA, Fischer S, Kopka K, Pietzsch J, Löser R. Preclinical evaluation of an 18F-labeled N ε-acryloyllysine piperazide for covalent targeting of transglutaminase 2. EJNMMI Radiopharm Chem 2024; 9:1. [PMID: 38165538 PMCID: PMC10761660 DOI: 10.1186/s41181-023-00231-1] [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: 11/06/2023] [Accepted: 12/15/2023] [Indexed: 01/03/2024] Open
Abstract
BACKGROUND Transglutaminase 2 (TGase 2) is a multifunctional protein and has a prominent role in various (patho)physiological processes. In particular, its transamidase activity, which is rather latent under physiological conditions, gains importance in malignant cells. Thus, there is a great need of theranostic probes for targeting tumor-associated TGase 2, and targeted covalent inhibitors appear to be particularly attractive as vector molecules. Such an inhibitor, equipped with a radionuclide suitable for noninvasive imaging, would be supportive for answering the general question on the possibility for functional characterization of tumor-associated TGase 2. For this purpose, the recently developed 18F-labeled Nε-acryloyllysine piperazide [18F]7b, which is a potent and selective irreversible inhibitor of TGase 2, was subject to a detailed radiopharmacological characterization herein. RESULTS An alternative radiosynthesis of [18F]7b is presented, which demands less than 300 µg of the respective trimethylammonio precursor per synthesis and provides [18F]7b in good radiochemical yields (17 ± 7%) and high (radio)chemical purities (≥ 99%). Ex vivo biodistribution studies in healthy mice at 5 and 60 min p.i. revealed no permanent enrichment of 18F-activity in tissues with the exception of the bone tissue. In vivo pretreatment with ketoconazole and in vitro murine liver microsome studies complemented by mass spectrometric analysis demonstrated that bone uptake originates from metabolically released [18F]fluoride. Further metabolic transformations of [18F]7b include mono-hydroxylation and glucuronidation. Based on blood sampling data and liver microsome experiments, pharmacokinetic parameters such as plasma and intrinsic clearance were derived, which substantiated the apparently rapid distribution of [18F]7b in and elimination from the organisms. A TGase 2-mediated uptake of [18F]7b in different tumor cell lines could not be proven. Moreover, evaluation of [18F]7b in melanoma tumor xenograft models based on A375-hS100A4 (TGase 2 +) and MeWo (TGase 2 -) cells by ex vivo biodistribution and PET imaging studies were not indicative for a specific targeting. CONCLUSION [18F]7b is a valuable radiometric tool to study TGase 2 in vitro under various conditions. However, its suitability for targeting tumor-associated TGase 2 is strongly limited due its unfavorable pharmacokinetic properties as demonstrated in rodents. Consequently, from a radiochemical perspective [18F]7b requires appropriate structural modifications to overcome these limitations.
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Affiliation(s)
- Robert Wodtke
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany.
| | - Markus Laube
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Sandra Hauser
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Sebastian Meister
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Friedrich-Alexander Ludwig
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318, Leipzig, Germany
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318, Leipzig, Germany
| | - Klaus Kopka
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, 04318, Leipzig, Germany
- School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstraße 4, 01069, Dresden, Germany
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany
- School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstraße 4, 01069, Dresden, Germany
| | - Reik Löser
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328, Dresden, Germany.
- School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstraße 4, 01069, Dresden, Germany.
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2
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Hou L, Rong J, Haider A, Ogasawara D, Varlow C, Schafroth MA, Mu L, Gan J, Xu H, Fowler CJ, Zhang MR, Vasdev N, Ametamey S, Cravatt BF, Wang L, Liang SH. Positron Emission Tomography Imaging of the Endocannabinoid System: Opportunities and Challenges in Radiotracer Development. J Med Chem 2020; 64:123-149. [PMID: 33379862 DOI: 10.1021/acs.jmedchem.0c01459] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endocannabinoid system (ECS) is involved in a wide range of biological functions and comprises cannabinoid receptors and enzymes responsible for endocannabinoid synthesis and degradation. Over the past 2 decades, significant advances toward developing drugs and positron emission tomography (PET) tracers targeting different components of the ECS have been made. Herein, we summarized the recent development of PET tracers for imaging cannabinoid receptors 1 (CB1R) and 2 (CB2R) as well as the key enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), particularly focusing on PET neuroimaging applications. State-of-the-art PET tracers for the ECS will be reviewed including their chemical design, pharmacological properties, radiolabeling, as well as preclinical and human PET imaging. In addition, this review addresses the current challenges for ECS PET biomarker development and highlights the important role of PET ligands to study disease pathophysiology as well as to facilitate drug discovery.
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Affiliation(s)
- Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Ahmed Haider
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Daisuke Ogasawara
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Cassis Varlow
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Michael A Schafroth
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Linjing Mu
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Jiefeng Gan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Christopher J Fowler
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States.,Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Simon Ametamey
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China.,Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
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3
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Chen Z, Hou L, Gan J, Cai Q, Ye W, Chen J, Tan Z, Zheng C, Li G, Xu H, Fowler CJ, Liang SH, Wang L. Synthesis and preliminary evaluation of a novel positron emission tomography (PET) ligand for imaging fatty acid amide hydrolase (FAAH). Bioorg Med Chem Lett 2020; 30:127513. [PMID: 32860981 DOI: 10.1016/j.bmcl.2020.127513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/14/2020] [Accepted: 08/20/2020] [Indexed: 01/09/2023]
Abstract
Fatty acid amide hydrolase (FAAH) exerts its main function in the catabolism of the endogenous chemical messenger anandamide (AEA), thus modulating the endocannabinoid (eCB) pathway. Inhibition of FAAH may serve as an effective strategy to relieve anxiety and possibly other central nervous system (CNS)-related disorders. Positron emission tomography (PET) would facilitate us to better understand the relationship between FAAH in certain disease conditions, and accelerate clinical translation of FAAH inhibitors by providing in vivo quantitative information. So far, most PET tracers show irreversible binding patterns with FAAH, which would result in complicated quantitative processes. Herein, we have identified a new FAAH inhibitor (1-((1-methyl-1H-indol-2-yl)methyl)piperidin-4-yl)(oxazol-2-yl)methanone (8) which inhibits the hydrolysis of AEA in the brain with high potency (IC50 value 11 nM at a substrate concentration of 0.5 µM), and without showing time-dependency. The PET tracer [11C]8 (also called [11C]FAAH-1906) was successfully radiolabeled with [11C]MeI in 17 ± 6% decay-corrected radiochemical yield (n = 7) with >74.0 GBq/μmol (2 Ci/μmol) molar activity and >99% radiochemical purity. Ex vivo biodistribution and blocking studies of [11C]8 in normal mice were also conducted, indicating good brain penetration, high brain target selectivity, and modest to excellent target selectivity in peripheral tissues. Thus, [11C]8 is a potentially useful PET ligand with enzyme inhibitory and target binding properties consistent with a reversible mode of action.
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Affiliation(s)
- Zhen Chen
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
| | - Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Jiefeng Gan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Qijun Cai
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Weijian Ye
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Jiahui Chen
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
| | - Zhiqiang Tan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Chao Zheng
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Charlestown, Boston, MA 02129, USA
| | - Guocong Li
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Christopher J Fowler
- Department of Integrative Medical Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA.
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
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4
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Yamasaki T, Ohya T, Mori W, Zhang Y, Wakizaka H, Nengaki N, Fujinaga M, Kikuchi T, Zhang MR. Development of an In Vivo Method to Estimate Effective Drug Doses and Quantify Fatty Acid Amide Hydrolase in Rodent Brain using Positron Emission Tomography Tracer [ 11C]DFMC. J Pharmacol Exp Ther 2020; 373:353-360. [PMID: 32241809 DOI: 10.1124/jpet.119.263772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/27/2020] [Indexed: 11/22/2022] Open
Abstract
Fatty acid amide hydrolase (FAAH) is a key enzyme in the endocannabinoid system. N-(3,4-Dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[11C]methylphenyl)thiazol-2-yl]-1-carboxamide ([11C]DFMC) was developed as an irreversible-type positron emission tomography (PET) tracer for FAAH. Here, we attempted to noninvasively estimate rate constant k3 (rate of transfer to the specifically-bound compartment) as a direct index for FAAH in the rat brain. First, the two-tissue compartment model analysis including three parameters [K1-k3, two-tissue compartment model for the irreversible-type radiotracer (2TCMi)] in PET study with [11C]DFMC was conducted, which provided 0.21 ± 0.04 ml·cm-3·min-1 of the net uptake value (Ki), an indirect index for FAAH, in the FAAH-richest region (the cingulate cortex). Subsequently, to noninvasively estimate Ki value, the reference model analysis (Patlak graphical analysis reference model) was tried using a time-activity curve of the spinal cord. In that result, the noninvasive Ki value (KREF) was concisely estimated with high correlation (r > 0.95) to Ki values based on 2TCMi. Using estimated KREF value, we tried to obtain calculated-k3 based on previously defined equations. The calculated k3 was successfully estimated with high correlation (r = 0.95) to direct k3 in 2TCMi. Finally, the dose relationship study using calculated k3 demonstrated that in vivo ED50 value of [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate, a major inhibitor of FAAH, was 66.4 µg/kg in rat brain. In conclusion, we proposed the calculated k3 as an alternative index corresponding to regional FAAH concentrations and suggested that PET with [11C]DFMC enables occupancy study for new pharmaceuticals targeting FAAH. SIGNIFICANCE STATEMENT: In the present study, we proposed calculated k3 as an alternative index corresponding with fatty acid amide hydrolase concentration. By using calculated k3, in vivo ED50 of [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate was successfully estimated to be 66.4 µg/kg for rats. Thus, we demonstrated the pharmacological utility of positron emission tomography with N-(3,4-dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[11C]methylphenyl)thiazol-2-yl]-1-carboxamide.
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Affiliation(s)
- Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Tomoyuki Ohya
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Wakana Mori
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Yiding Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Hidekatsu Wakizaka
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Masayuki Fujinaga
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Tatsuya Kikuchi
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
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5
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Ruivo E, Elvas F, Adhikari K, Vangestel C, Van Haesendonck G, Lemière F, Staelens S, Stroobants S, Van der Veken P, wyffels L, Augustyns K. Preclinical Evaluation of a Novel 18F-Labeled dTCO-Amide Derivative for Bioorthogonal Pretargeted Positron Emission Tomography Imaging. ACS OMEGA 2020; 5:4449-4456. [PMID: 32175492 PMCID: PMC7066555 DOI: 10.1021/acsomega.9b03584] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/31/2019] [Indexed: 06/07/2023]
Abstract
Pretargeted positron emission tomography (PET) imaging based on the bioorthogonal inverse-electron-demand Diels-Alder reaction between tetrazines (Tz) and trans-cyclooctenes (TCO) has emerged as a promising tool for solid tumor imaging, allowing the use of short-lived radionuclides in immune-PET applications. With this strategy, it became possible to achieve desirable target-to-background ratios and at the same time to decrease the radiation burden to nontargeted tissues because of the fast clearance of small PET probes. Here, we show the synthesis of novel 18F-labeled dTCO-amide probes for pretargeted immuno-PET imaging. The PET probes were evaluated regarding their stability, reactivity toward tetrazine, and pharmacokinetic profile. [ 18 F]MICA-213 showed an extremely fast kinetic rate (10,553 M-1 s-1 in 50:50 MeOH/water), good stability in saline and plasma up to 4 h at 37 °C with no isomerization observed, and the biodistribution in healthy mice revealed a mixed hepatobiliary and renal clearance with no defluorination and low background in other tissues. [ 18 F]MICA-213 was further used for in vivo pretargeted immune-PET imaging carried out in nude mice bearing LS174T colorectal tumors that were previously treated with a tetrazine-modified anti-TAG-72 monoclonal antibody (CC49). Pretargeted μPET imaging results showed clear visualization of the tumor tissue with a significantly higher uptake when compared to the control.
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Affiliation(s)
- Eduardo Ruivo
- Laboratory
of Medicinal Chemistry, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
| | - Filipe Elvas
- Laboratory
of Medicinal Chemistry, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
- Department
of Nuclear Medicine, University Hospital
Antwerp, Edegem 2650, Belgium
- Molecular
Imaging Center Antwerp, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
| | - Karuna Adhikari
- Laboratory
of Medicinal Chemistry, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
| | - Christel Vangestel
- Department
of Nuclear Medicine, University Hospital
Antwerp, Edegem 2650, Belgium
| | - Glenn Van Haesendonck
- Biomolecular
and Analytical Mass Spectrometry, University
of Antwerp, Antwerp 2020, Belgium
| | - Filip Lemière
- Biomolecular
and Analytical Mass Spectrometry, University
of Antwerp, Antwerp 2020, Belgium
| | - Steven Staelens
- Molecular
Imaging Center Antwerp, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
| | - Sigrid Stroobants
- Department
of Nuclear Medicine, University Hospital
Antwerp, Edegem 2650, Belgium
- Molecular
Imaging Center Antwerp, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
| | - Pieter Van der Veken
- Laboratory
of Medicinal Chemistry, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
| | - Leonie wyffels
- Department
of Nuclear Medicine, University Hospital
Antwerp, Edegem 2650, Belgium
- Molecular
Imaging Center Antwerp, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
| | - Koen Augustyns
- Laboratory
of Medicinal Chemistry, University of Antwerp, Antwerp, Wilrijk 2610, Belgium
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6
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Elvas F, Vanden Berghe T, Adriaenssens Y, Vandenabeele P, Augustyns K, Staelens S, Stroobants S, Van der Veken P, Wyffels L. Caspase-3 probes for PET imaging of apoptotic tumor response to anticancer therapy. Org Biomol Chem 2020; 17:4801-4824. [PMID: 31033991 DOI: 10.1039/c9ob00657e] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Apoptosis is a highly regulated process involved in the normal organism development and homeostasis. In the context of anticancer therapy, apoptosis is also studied intensively in an attempt to induce cell death in cancer cells. Caspase activation is a known key event in the apoptotic process. In particular, active caspase-3 and -7 are the common effectors in several apoptotic pathways, therefore effector caspase activation may be a promising biomarker for response evaluation to anticancer therapy. Quantitative imaging of apoptosis in vivo could provide early assessment of therapeutic effectiveness and could also be used in drug development to evaluate the efficacy as well as potential toxicity of novel treatments. Positron Emission Tomography (PET) is a highly sensitive molecular imaging modality that allows non-invasive in vivo imaging of biological processes such as apoptosis by using radiolabeled probes. Here we describe the development and evaluation of fluorine-18-labeled caspase-3 activity-based probes (ABPs) for PET imaging of apoptosis. ABPs were selected by screening of a small library of fluorine-19-labeled DEVD peptides containing different electrophilic warhead groups. An acyloxymethyl ketone was identified with low nanomolar affinity for caspase-3 and was radiolabeled with fluorine-18. The resulting radiotracer, [18F]MICA-302, showed good labeling of active caspase-3 in vitro and favorable pharmacokinetic properties. A μPET imaging experiment in colorectal tumor xenografts demonstrated an increased tumor accumulation of [18F]MICA-302 in drug-treated versus control animals. Therefore, our data suggest this radiotracer may be useful for clinical PET imaging of response to anticancer therapy.
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Affiliation(s)
- Filipe Elvas
- Molecular Imaging Center Antwerp, University of Antwerp, 2610 Wilrijk, Belgium.
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7
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Ruivo E, Adhikari K, Elvas F, Fissers J, Vangestel C, Staelens S, Stroobants S, Van der Veken P, Wyffels L, Augustyns K. Improved stability of a novel fluorine-18 labeled TCO analogue for pretargeted PET imaging. Nucl Med Biol 2019; 76-77:36-42. [PMID: 31707309 DOI: 10.1016/j.nucmedbio.2019.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/24/2019] [Accepted: 11/01/2019] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Biorthogonal pretargeted imaging using the inverse electron demand Diels Alder (IEDDA) reaction between tetrazine (Tz) and trans-cyclooctene (TCO) is one of the most attractive strategies in molecular imaging. It allows the use of short-lived radioisotopes such as fluorine-18 for imaging of long circulating vectors with improved imaging contrast and reduced radiation dose. Here we aim to develop a novel 18F-labeled trans-cyclooctene (TCO) with improved metabolic stability and assess its potential usefulness in a pretargeted PET imaging approach. METHODS We have synthetized a new TCO-analogue containing a 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) chelator, allowing radiolabeling by chelation with aluminum fluoride (Al[18F]F). Stability and pharmacokinetic profile of Al[18F]F-NOTA-TCO ([18F]MICA-205) were evaluated in healthy animals at different timepoints after injection of the radiotracer. To assess the potential use of this new PET tracer for tumor targeting, in vivo pretargeted PET imaging was performed in LS174T tumor-bearing mice pre-treated with a tetrazine-modified anti-TAG-72 monoclonal antibody (CC49). RESULTS The radiotracer was obtained with a radiochemical yield (RCY) of 12.8 ± 2.8% and a radiochemical purity (RCP) of ≥95%. It also showed a promising in vivo stability with 51.9 ± 5.16% of radiotracer remaining intact after 1 h. The biodistribution in healthy mice demonstrated mixed hepatobiliary and renal clearance, with a rapid blood clearance and low uptake in other tissues. The low bone uptake indicated lack of tracer defluorination. Interestingly, a pretargeted PET imaging experiment showed a significantly increased radiotracer uptake (0.67 ± 0.16%ID/g, p < 0.001) in the tumors of mice pre-treated with CC49-tetrazine compared to the CC49 alone (0.16 ± 0.08%ID/g). CONCLUSIONS [18F]MICA-205 represents a large improvement in in vivo metabolic stability compared to previous reported 18F-labeled TCOs, allowing a clear visualization of tumor tissue in a small-animal pretargeted PET imaging experiment. Despite the favorable in vivo stability and image contrast obtained with [18F]MICA-205, the development of next-generation derivatives with increased absolute tumor uptake is warranted for future pretargeting applications.
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Affiliation(s)
- Eduardo Ruivo
- Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium.
| | - Karuna Adhikari
- Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium
| | - Filipe Elvas
- Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium; University Hospital Antwerp, Department of Nuclear Medicine, Edegem, Belgium; Molecular Imaging Center Antwerp, University of Antwerp, Antwerp, Belgium
| | - Jens Fissers
- Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium
| | - Christel Vangestel
- Molecular Imaging Center Antwerp, University of Antwerp, Antwerp, Belgium
| | - Steven Staelens
- Molecular Imaging Center Antwerp, University of Antwerp, Antwerp, Belgium
| | - Sigrid Stroobants
- University Hospital Antwerp, Department of Nuclear Medicine, Edegem, Belgium; Molecular Imaging Center Antwerp, University of Antwerp, Antwerp, Belgium
| | | | - Leonie Wyffels
- University Hospital Antwerp, Department of Nuclear Medicine, Edegem, Belgium; Molecular Imaging Center Antwerp, University of Antwerp, Antwerp, Belgium
| | - Koen Augustyns
- Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium
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8
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Ligresti A, Silvestri C, Vitale RM, Martos JL, Piscitelli F, Wang JW, Allarà M, Carling RW, Luongo L, Guida F, Illiano A, Amoresano A, Maione S, Amodeo P, Woodward DF, Di Marzo V, Marino G. FAAH-Catalyzed C-C Bond Cleavage of a New Multitarget Analgesic Drug. ACS Chem Neurosci 2019; 10:424-437. [PMID: 30226747 DOI: 10.1021/acschemneuro.8b00315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The discovery of extended catalytic versatilities is of great importance in both the chemistry and biotechnology fields. Fatty acid amide hydrolase (FAAH) belongs to the amidase signature superfamily and is a major endocannabinoid inactivating enzyme using an atypical catalytic mechanism involving hydrolysis of amide and occasionally ester bonds. FAAH inhibitors are efficacious in experimental models of neuropathic pain, inflammation, and anxiety, among others. We report a new multitarget drug, AGN220653, containing a carboxyamide-4-oxazole moiety and endowed with efficacious analgesic and anti-inflammatory activities, which are partly due to its capability of achieving inhibition of FAAH, and subsequently increasing the tissue concentrations of the endocannabinoid anandamide. This inhibitor behaves as a noncompetitive, slowly reversible inhibitor. Autoradiography of purified FAAH incubated with AGN220653, opportunely radiolabeled, indicated covalent binding followed by fragmentation of the molecule. Molecular docking suggested a possible nucleophilic attack by FAAH-Ser241 on the carbonyl group of the carboxyamide-4-oxazole moiety, resulting in the cleavage of the C-C bond between the oxazole and the carboxyamide moieties, instead of either of the two available amide bonds. MRM-MS analyses only detected the Ser241-assisted formation of the carbamate intermediate, thus confirming the cleavage of the aforementioned C-C bond. Quantum mechanics calculations were fully consistent with this mechanism. The study exemplifies how FAAH structural features and mechanism of action may override the binding and reactivity propensities of substrates. This unpredicted mechanism could pave the way to the future development of a completely new class of amidase inhibitors, of potential use against pain, inflammation, and mood disorders.
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Affiliation(s)
- Alessia Ligresti
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, National Research Council of Italy, Pozzuoli 80078, Italy
| | - Cristoforo Silvestri
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, National Research Council of Italy, Pozzuoli 80078, Italy
| | - Rosa Maria Vitale
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, National Research Council of Italy, Pozzuoli 80078, Italy
| | - Jose L. Martos
- Discovery Department, Selcia Limited, Ongar CM5 0GS, United Kingdom
| | - Fabiana Piscitelli
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, National Research Council of Italy, Pozzuoli 80078, Italy
| | - Jenny W. Wang
- Department of Biological Sciences, Allergan Inc., Irvine, California 92623, United States
| | - Marco Allarà
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, National Research Council of Italy, Pozzuoli 80078, Italy
| | | | - Livio Luongo
- Department of Experimental Medicine, Pharmacology Division, University of Campania, Naples 80138, Italy
| | - Francesca Guida
- Department of Experimental Medicine, Pharmacology Division, University of Campania, Naples 80138, Italy
| | - Anna Illiano
- Department of Chemical Sciences, University of Naples “Federico II”, Naples 80126, Italy
| | - Angela Amoresano
- Department of Chemical Sciences, University of Naples “Federico II”, Naples 80126, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, Pharmacology Division, University of Campania, Naples 80138, Italy
| | - Pietro Amodeo
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, National Research Council of Italy, Pozzuoli 80078, Italy
| | - David F. Woodward
- Department of Biological Sciences, Allergan Inc., Irvine, California 92623, United States
| | - Vincenzo Di Marzo
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, National Research Council of Italy, Pozzuoli 80078, Italy
- Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Universitè Laval, Quebec City G1V 0A6, Canada
| | - Gennaro Marino
- Department of Chemical Sciences, University of Naples “Federico II”, Naples 80126, Italy
- University “Suor Orsola Benincasa”, Naples 80132, Italy
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9
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Abstract
Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health. However, the expression and/or activity of these important enzymes can change in many different diseases and therefore represent exciting targets for the development of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radiotracers. This review focuses on recently reported radiolabeled substrates, reversible inhibitors, and irreversible inhibitors investigated as PET and SPECT tracers for imaging hydrolytic enzymes. By learning from the most successful examples of tracer development for hydrolytic enzymes, it appears that an early focus on careful enzyme kinetics and cell-based studies are key factors for identifying potentially useful new molecular imaging agents.
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Affiliation(s)
- Brian P Rempel
- 1 Department of Science, Augustana Faculty, University of Alberta, Edmonton, Alberta, Canada
| | - Eric W Price
- 2 Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Christopher P Phenix
- 2 Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.,3 Biomarker Discovery, Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada
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10
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Cheng G, Werner TJ, Newberg A, Alavi A. Failed PET Application Attempts in the Past, Can We Avoid Them in the Future? Mol Imaging Biol 2016; 18:797-802. [DOI: 10.1007/s11307-016-1017-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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11
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Wang L, Yui J, Wang Q, Zhang Y, Mori W, Shimoda Y, Fujinaga M, Kumata K, Yamasaki T, Hatori A, Rotstein BH, Collier TL, Ran C, Vasdev N, Zhang MR, Liang SH. Synthesis and Preliminary PET Imaging Studies of a FAAH Radiotracer ([¹¹C]MPPO) Based on α-Ketoheterocyclic Scaffold. ACS Chem Neurosci 2016; 7:109-18. [PMID: 26505525 DOI: 10.1021/acschemneuro.5b00248] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Fatty acid amide hydrolase (FAAH) is one of the principle enzymes for metabolizing endogenous cannabinoid neurotransmitters such as anandamide, and thus regulates endocannabinoid (eCB) signaling. Selective pharmacological blockade of FAAH has emerged as a potential therapy to discern the endogenous functions of anandamide-mediated eCB pathways in anxiety, pain, and addiction. Quantification of FAAH in the living brain by positron emission tomography (PET) would help our understanding of the endocannabinoid system in these conditions. While most FAAH radiotracers operate by an irreversible ("suicide") binding mechanism, a FAAH tracer with reversibility would facilitate quantitative analysis. We have identified and radiolabeled a reversible FAAH inhibitor, 7-(2-[(11)C]methoxyphenyl)-1-(5-(pyridin-2-yl)oxazol-2-yl)heptan-1-one ([(11)C]MPPO) in 13% radiochemical yield (nondecay corrected) with >99% radiochemical purity and 2 Ci/μmol (74 GBq/μmol) specific activity. The tracer showed moderate brain uptake (0.8 SUV) with heterogeneous brain distribution. However, blocking studies with a potent FAAH inhibitor URB597 demonstrated a low to modest specificity to the target. Measurement of lipophilicity, metabolite, and efflux pathway analysis were also performed to study the pharmacokinetic profile of [(11)C]MPPO. In all, we reported an efficient radiolabeling and preliminary evaluation of the first-in-class FAAH inhibitor [(11)C]MPPO with α-ketoheterocyclic scaffold.
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Affiliation(s)
- Lu Wang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Joji Yui
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Qifan Wang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Yiding Zhang
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Wakana Mori
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Yoko Shimoda
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Masayuki Fujinaga
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Akiko Hatori
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Benjamin H. Rotstein
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Thomas Lee Collier
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
- Advion BioSystems, 10 Brown Road, Suite 101, Ithaca, New York 14850, United States
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Ming-Rong Zhang
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Steven H. Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
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12
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Shimoda Y, Fujinaga M, Hatori A, Yui J, Zhang Y, Nengaki N, Kurihara Y, Yamasaki T, Xie L, Kumata K, Ishii H, Zhang MR. N-(3,4-Dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[(11)C]methylphenyl)thiazol-2-yl]-1-carboxamide: A promising positron emission tomography ligand for fatty acid amide hydrolase. Bioorg Med Chem 2015; 24:627-34. [PMID: 26740152 DOI: 10.1016/j.bmc.2015.12.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 12/13/2022]
Abstract
To visualize fatty acid amide hydrolase (FAAH) in brain in vivo, we developed a novel positron emission tomography (PET) ligand N-(3,4-dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[(11)C]methylphenyl)thiazol-2-yl]-1-carboxamide ([(11)C]DFMC, [(11)C]1). DFMC (1) was shown to have high binding affinity (IC50: 6.1nM) for FAAH. [(11)C]1 was synthesized by C-(11)C coupling reaction of arylboronic ester 2 with [(11)C]methyl iodide in the presence of Pd catalyst. At the end of synthesis, [(11)C]1 was obtained with a radiochemical yield of 20±10% (based on [(11)C]CO2, decay-corrected, n=5) and specific activity of 48-166GBq/μmol. After the injection of [(11)C]1 in mice, high uptake of radioactivity (>2% ID/g) was distributed in the lung, liver, kidney, and brain, organs with high FAAH expression. PET images of rat brains for [(11)C]1 revealed high uptakes in the cerebellar nucleus (SUV=2.4) and frontal cortex (SUV=2.0), two known brain regions with high FAAH expression. Pretreatment with the FAAH-selective inhibitor URB597 reduced the brain uptake. Higher than 90% of the total radioactivity in the rat brain was irreversible at 30min after the radioligand injection. The present results indicate that [(11)C]1 is a promising PET ligand for imaging of FAAH in living brain.
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Affiliation(s)
- Yoko Shimoda
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Masayuki Fujinaga
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Akiko Hatori
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Joji Yui
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yiding Zhang
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Nobuki Nengaki
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan; SHI Accelerator Service Co. Ltd, 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
| | - Yusuke Kurihara
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan; SHI Accelerator Service Co. Ltd, 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
| | - Tomoteru Yamasaki
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Lin Xie
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Hideki Ishii
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Ming-Rong Zhang
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
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13
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Pandey MK, DeGrado TR, Qian K, Jacobson MS, Hagen CE, Duclos RI, Gatley SJ. Synthesis and preliminary evaluation of N-(16-18F-fluorohexadecanoyl)ethanolamine (18F-FHEA) as a PET probe of N-acylethanolamine metabolism in mouse brain. ACS Chem Neurosci 2014; 5:793-802. [PMID: 25003845 DOI: 10.1021/cn400214j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
N-Acylethanolamines are lipid signaling molecules found throughout the plant and animal kingdoms. The best-known mammalian compound of this class is anandamide, N-arachidonoylethanolamine, one of the endogenous ligands of cannabinoid CB1 and CB2 receptors. Signaling by N-acylethanolamines is terminated by release of the ethanolamine moiety by hydrolyzing enzymes such as fatty acid amide hydrolase (FAAH) and N-acylethanolamine-hydrolyzing amidase (NAAA). Herein, we report the design and synthesis of N-(16-(18)F-fluorohexadecanoyl)ethanolamine ((18)F-FHEA) as a positron emission tomography (PET) probe for imaging the activity of N-acylethanolamine hydrolyzing enzymes in the brain. Following intravenous administration of (18)F-FHEA in Swiss Webster mice, (18)F-FHEA was extracted from blood by the brain and underwent hydrolysis at the amide bond and incorporation of the resultant (18)F-fluorofatty acid into complex lipid pools. Pretreatment of mice with the FAAH inhibitor URB-597 (1 mg/kg IP) resulted in significantly slower (18)F-FHEA incorporation into lipid pools, but overall (18)F concentrations in brain regions were not altered. Likewise, pretreatment with a NAAA inhibitor, (S)-N-(2-oxo-3-oxytanyl)biphenyl-4-carboxamide (30 mg/kg IV), did not significantly affect the uptake of (18)F-FHEA in the brain. Although evidence was found that (18)F-FHEA behaves as a substrate of FAAH in the brain, the lack of sensitivity of brain uptake kinetics to FAAH inhibition discourages its use as a metabolically trapped PET probe of N-acylethanolamine hydrolyzing enzyme activity.
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Affiliation(s)
- Mukesh K. Pandey
- Brigham
and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Timothy R. DeGrado
- Brigham
and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Kun Qian
- Department
of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | | | | | - Richard I. Duclos
- Department
of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - S. John Gatley
- Department
of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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14
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Rotstein BH, Wey HY, Shoup TM, Wilson AA, Liang SH, Hooker JM, Vasdev N. PET imaging of fatty acid amide hydrolase with [(18)F]DOPP in nonhuman primates. Mol Pharm 2014; 11:3832-8. [PMID: 25004399 PMCID: PMC4224570 DOI: 10.1021/mp500316h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Fatty acid amide hydrolase (FAAH) regulates endocannabinoid signaling. [(11)C]CURB, an irreversibly binding FAAH inhibitor, has been developed for clinical research imaging with PET. However, no fluorine-18 labeled radiotracer for FAAH has yet advanced to human studies. [(18)F]DOPP ([(18)F]3-(4,5-dihydrooxazol-2-yl)phenyl (5-fluoropentyl)carbamate) has been identified as a promising (18)F-labeled analogue based on rodent studies. The goal of this work is to evaluate [(18)F]DOPP in nonhuman primates to support its clinical translation. High specific activity [(18)F]DOPP (5-6 Ci·μmol(-1)) was administered intravenously (iv) to three baboons (2M/1F, 3-4 years old). The distribution and pharmacokinetics were quantified following a 2 h dynamic imaging session using a simultaneous PET/MR scanner. Pretreatment with the FAAH-selective inhibitor, URB597, was carried out at 200 or 300 μg/kg iv, 10 min prior to [(18)F]DOPP administration. Rapid arterial blood sampling for the first 3 min was followed by interval sampling with metabolite analysis to provide a parent radiotracer plasma input function that indicated ∼95% baseline metabolism at 60 min and a reduced rate of metabolism after pretreatment with URB597. Regional distribution data were analyzed with 1-, 2-, and 3-tissue compartment models (TCMs), with and without irreversible trapping since [(18)F]DOPP covalently links to the active site of FAAH. Consistent with previous findings for [(11)C]CURB, the 2TCM with irreversible binding was found to provide the best fit for modeling the data in all regions. The composite parameter λk3 was therefore used to evaluate whole brain (WB) and regional binding of [(18)F]DOPP. Pretreatment studies showed inhibition of λk3 across all brain regions (WB baseline: 0.112 mL/cm(3)/min; 300 μg/kg URB597: 0.058 mL/cm(3)/min), suggesting that [(18)F]DOPP binding is specific for FAAH, consistent with previous rodent data.
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Affiliation(s)
- Benjamin H Rotstein
- Division of Nuclear Medicine and Molecular Imaging & Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital , Boston, Massachusetts 02114, United States
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15
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Holland JP, Liang SH, Rotstein BH, Collier TL, Stephenson NA, Greguric I, Vasdev N. Alternative approaches for PET radiotracer development in Alzheimer's disease: imaging beyond plaque. J Labelled Comp Radiopharm 2013; 57:323-31. [PMID: 24327420 DOI: 10.1002/jlcr.3158] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/29/2013] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) and related dementias show increasing clinical prevalence, yet our understanding of the etiology and pathobiology of disease-related neurodegeneration remains limited. In this regard, noninvasive imaging with radiotracers for positron emission tomography (PET) presents a unique tool for quantifying spatial and temporal changes in characteristic biological markers of brain disease and for assessing potential drug efficacy. PET radiotracers targeting different protein markers are being developed to address questions pertaining to the molecular and/or genetic heterogeneity of AD and related dementias. For example, radiotracers including [(11) C]-PiB and [(18) F]-AV-45 (Florbetapir) are being used to measure the density of Aβ-plaques in AD patients and to interrogate the biological mechanisms of disease initiation and progression. Our focus is on the development of novel PET imaging agents, targeting proteins beyond Aβ-plaques, which can be used to investigate the broader mechanism of AD pathogenesis. Here, we present the chemical basis of various radiotracers which show promise in preclinical or clinical studies for use in evaluating the phenotypic or biochemical characteristics of AD. Radiotracers for PET imaging neuroinflammation, metal ion association with Aβ-plaques, tau protein, cholinergic and cannabinoid receptors, and enzymes including glycogen-synthase kinase-3β and monoamine oxidase B amongst others, and their connection to AD are highlighted.
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Affiliation(s)
- Jason P Holland
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Department of Radiology, Harvard Medical School, 55 Fruit St., White 427, Boston, Massachusetts, 02114, USA; Life Sciences, Australian Nuclear Science and Technology Organisation, Kirrawee, New South Wales, 2232, Australia
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16
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Liu P, Hamill TG, Chioda M, Chobanian H, Fung S, Guo Y, Chang L, Bakshi R, Hong Q, Dellureficio J, Lin LS, Abbadie C, Alexander J, Jin H, Mandala S, Shiao LL, Li W, Sanabria S, Williams D, Zeng Z, Hajdu R, Jochnowitz N, Rosenbach M, Karanam B, Madeira M, Salituro G, Powell J, Xu L, Terebetski JL, Leone JF, Miller P, Cook J, Holahan M, Joshi A, O’Malley S, Purcell M, Posavec D, Chen TB, Riffel K, Williams M, Hargreaves R, Sullivan KA, Nargund RP, DeVita RJ. Discovery of MK-3168: A PET Tracer for Imaging Brain Fatty Acid Amide Hydrolase. ACS Med Chem Lett 2013; 4:509-13. [PMID: 24900701 DOI: 10.1021/ml4000996] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/20/2013] [Indexed: 11/29/2022] Open
Abstract
We report herein the discovery of a fatty acid amide hydrolase (FAAH) positron emission tomography (PET) tracer. Starting from a pyrazole lead, medicinal chemistry efforts directed toward reducing lipophilicity led to the synthesis of a series of imidazole analogues. Compound 6 was chosen for further profiling due to its appropriate physical chemical properties and excellent FAAH inhibition potency across species. [(11)C]-6 (MK-3168) exhibited good brain uptake and FAAH-specific signal in rhesus monkeys and is a suitable PET tracer for imaging FAAH in the brain.
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Affiliation(s)
| | - Terence G. Hamill
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Wenping Li
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Sandra Sanabria
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - David Williams
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Zhizhen Zeng
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | | | | | | | | | | | | | | | | | | | | | - Patricia Miller
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Jacquelynn Cook
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Marie Holahan
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Aniket Joshi
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Stacey O’Malley
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Mona Purcell
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Diane Posavec
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Tsing-Bau Chen
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Kerry Riffel
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Mangay Williams
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Richard Hargreaves
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
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Carr RL, Adams AL, Kepler DR, Ward AB, Ross MK. Induction of endocannabinoid levels in juvenile rat brain following developmental chlorpyrifos exposure. Toxicol Sci 2013; 135:193-201. [PMID: 23761300 DOI: 10.1093/toxsci/kft126] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The endogenous cannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) play vital roles during nervous system development. The degradation of 2-AG and AEA is mediated by monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), respectively. These enzymes are inhibited following developmental chlorpyrifos (CPF) exposure. To investigate whether this inhibition is persistent or whether accumulation of endocannabinoids in the brain occurs, 10-day-old rat pups were orally exposed daily for 7 days to either corn oil or increasing dosages of CPF (1, 2.5, or 5mg/kg), and forebrains were collected at 4, 12, 24, and 48h following the last administration. All dosages inhibited cholinesterase (ChE), FAAH, and MAGL, and elevated AEA and 2-AG levels with the greatest effect occurring at 12h with ChE, FAAH, AEA, and 2-AG and at 4h with MAGL. With the high dosage, return to control levels occurred with 2-AG (48h) only. With the medium dosage, return to control levels occurred with MAGL, 2-AG, and AEA (48h) but not with ChE or FAAH. With the low dosage, return to control levels occurred with MAGL (12h), ChE and 2-AG (24h), and AEA (48h) but not with FAAH. With the lowest dosage, peak inhibition of FAAH (52%) is greater than that of ChE (24%) and that level of FAAH inhibition is sufficient to induce a persistent pattern of elevated AEA. It is possible that this pattern of elevation could alter the appropriate development of neuronal brain circuits.
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Affiliation(s)
- Russell L Carr
- Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi 39762-6100, USA.
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Hicks JW, Parkes J, Sadovski O, Tong J, Houle S, Vasdev N, Wilson AA. Synthesis and preclinical evaluation of [11C-carbonyl]PF-04457845 for neuroimaging of fatty acid amide hydrolase. Nucl Med Biol 2013; 40:740-6. [PMID: 23731552 DOI: 10.1016/j.nucmedbio.2013.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/09/2013] [Accepted: 04/17/2013] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Fatty acid amide hydrolase (FAAH) has a significant role in regulating endocannabinoid signaling in the central nervous system. As such, FAAH inhibitors are being actively sought for pain, addiction, and other indications. This has led to the recent pursuit of positron emission tomography (PET) radiotracers targeting FAAH. We report herein the preparation and preclinical evaluation of [(11)C-carbonyl]PF-04457845, an isotopologue of the potent irreversible FAAH inhibitor. METHODS PF-04457845 was radiolabeled at the carbonyl position via automated [(11)C]CO(2)-fixation. Ex vivo brain biodistribution of [(11)C-carbonyl]PF-04457845 was carried out in conscious rats. Specificity was determined by pre-administration of PF-04457845 or URB597 prior to [(11)C-carbonyl]PF-04457845. In a separate experiment, rats injected with the title radiotracer had whole brains excised, homogenized and extracted to examine irreversible binding to brain parenchyma. RESULTS The title compound was prepared in 5 ± 1% (n = 4) isolated radiochemical yield based on starting [(11)C]CO(2) (decay uncorrected) within 25 min from end-of-bombardment in >98% radiochemical purity and a specific activity of 73.5 ± 8.2 GBq/μmol at end-of-synthesis. Uptake of [(11)C-carbonyl]PF-04457845 into the rat brain was high (range of 1.2-4.4 SUV), heterogeneous, and in accordance with reported FAAH distribution. Saturable binding was demonstrated by a dose-dependent reduction in brain radioactivity uptake following pre-treatment with PF-04457845. Pre-treatment with the prototypical FAAH inhibitor, URB597, reduced the brain radiotracer uptake in all regions by 71-81%, demonstrating specificity for FAAH. The binding of [(11)C-carbonyl]PF-04457845 to FAAH at 40 min post injection was irreversible as 98% of the radioactivity in the brain could not be extracted. CONCLUSIONS [(11)C-carbonyl]PF-04457845 was rapidly synthesized via an automated radiosynthesis. Ex vivo biodistribution studies in conscious rodents demonstrate that [11C PF-04457845 is a promising candidate radiotracer for imaging FAAH in the brain with PET. These results coupled with the known pharmacology and toxicology of PF-04457845 should facilitate clinical translation of this radiotracer.
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Affiliation(s)
- Justin W Hicks
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
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The synthesis and in vivo evaluation of [18F]PF-9811: a novel PET ligand for imaging brain fatty acid amide hydrolase (FAAH). Nucl Med Biol 2012; 39:1058-67. [PMID: 22571907 DOI: 10.1016/j.nucmedbio.2012.03.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 03/22/2012] [Accepted: 03/26/2012] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Fatty acid amide hydrolase (FAAH) is responsible for the enzymatic degradation of the fatty acid amide family of signaling lipids, including the endogenous cannabinoid (endocannabinoid) anandamide. The involvement of the endocannabinoid system in pain and other nervous system disorders has made FAAH an attractive target for drug development. Companion molecular imaging probes are needed, however, to assess FAAH inhibition in the nervous system in vivo. We report here the synthesis and in vivo evaluation of [(18)F]PF-9811, a novel PET ligand for non-invasive imaging of FAAH in the brain. METHODS The potency and selectivity of unlabeled PF-9811 were determined by activity-based protein profiling (ABPP) both in vitro and in vivo. [(18)F]PF-9811 was synthesized in a 3-step, one-pot reaction sequence, followed by HPLC purification. Biological evaluation was performed by biodistribution and dynamic PET imaging studies in male rats. The specificity of [(18)F]PF-9811 uptake was evaluated by pre-administration of PF-04457845, a potent and selective FAAH inhibitor, 1h prior to radiotracer injection. RESULTS Biodistribution studies show good uptake (SUV~0.8 at 90 min) of [(18)F]PF-9811 in rat brain, with significant reduction of the radiotracer in all brain regions (37%-73% at 90 min) in blocking experiments. Dynamic PET imaging experiments in rat confirmed the heterogeneous uptake of [(18)F]PF-9811 in brain regions with high FAAH enzymatic activity, as well as statistically significant reductions in signal following pre-administration of the blocking compound PF-04457845. CONCLUSIONS [(18)F]PF-9811 is a promising PET imaging agent for FAAH. Biodistribution and PET imaging experiments show that the tracer has good uptake in brain, regional heterogeneity, and specific binding as determined by blocking experiments with the highly potent and selective FAAH inhibitor, PF-04457845.
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Recent Advances in the Development of PET and SPECT Tracers for Brain Imaging. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2012. [DOI: 10.1016/b978-0-12-396492-2.00008-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Wilson AA, Garcia A, Parkes J, Houle S, Tong J, Vasdev N. [11C]CURB: Evaluation of a novel radiotracer for imaging fatty acid amide hydrolase by positron emission tomography. Nucl Med Biol 2011; 38:247-53. [PMID: 21315280 DOI: 10.1016/j.nucmedbio.2010.08.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 08/05/2010] [Accepted: 08/08/2010] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Fatty acid amide hydrolase (FAAH) is the enzyme responsible for metabolising the endogenous cannabinoid, anandamide, and thus represents an important target for molecular imaging. To date, no radiotracer has been shown to be useful for imaging of FAAH using either positron emission tomography (PET) or single photon emission computed tomography (SPECT). We here determine the suitability of a novel carbon-11-labeled inhibitor of FAAH via ex vivo biodistribution studies in rat brain in conjunction with pharmacological challenges. METHODS A potent irreversible inhibitor of FAAH, URB694, radiolabeled with carbon-11 in the carbonyl position ([(11)C]CURB), was administered to male rats via tail-vein injection. Rats were sacrificed at various time points postinjection, and tissue samples were dissected, counted and weighed. Specific binding to FAAH was investigated by pretreatment of animals with URB694 or URB597. For metabolism and mechanism of binding studies, whole brains were excised post-radiotracer injection, homogenised and extracted exhaustively with 80% aq. acetonitrile to determine the time course and fraction of radioactivity that was irreversibly bound to brain parenchyma. RESULTS Upon intravenous injection into rats, [(11)C]CURB showed high brain uptake [standard uptake value (SUV) of 1.6-2.4 at 5 min] with little washout over time, which is characteristic of irreversible binding. Highest uptake of radioactivity was seen in the cortex, intermediate in the cerebellum and lowest in the hypothalamus, reflecting the reported distribution of FAAH. Brain uptake of radioactivity was decreased in a dose-dependent manner by pretreatment with increasing amounts of URB694, demonstrating that binding was saturable. Pretreatment with the well-characterised FAAH inhibitor, URB597, reduced binding in all brain regions by 70-80%. Homogenised brain extraction experiments demonstrated unequivocally that [(11)C]CURB was irreversibly bound to FAAH. CONCLUSIONS The title radiotracer demonstrates favourable properties such as good brain uptake, regional heterogeneity and specificity of binding based on ex vivo biodistribution studies in conscious rat brain. [(11)C]CURB represents a highly promising radiotracer for the imaging of FAAH using PET.
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Affiliation(s)
- Alan A Wilson
- PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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