1
|
Wang J, Li Y, El Fakhri G. Advances and Insights in Positron Emission Tomography Tracers for Metabotropic Glutamate Receptor 4 Imaging. J Med Chem 2024; 67:10517-10529. [PMID: 38924702 PMCID: PMC11290609 DOI: 10.1021/acs.jmedchem.3c02431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
Positron emission tomography (PET) imaging employs positron-emitting radioisotopes to visualize biological processes in living subjects with high sensitivity and quantitative accuracy. As the most translational molecular imaging modality, PET can detect and image a wide range of radiotracers with minimal or no modification to parent drugs or targeting molecules. This Perspective provides a comprehensive analysis of developing PET radioligands using allosteric modulators for the metabotropic glutamate receptor subtype 4 (mGluR4) as a therapeutic target for neurological disorders. We focus on the selection of lead compounds from various chemotypes of mGluR4 positive allosteric modulators (PAMs) and discuss the challenges and systematic characterization required in developing brain-penetrant PET tracers specific for mGluR4. Through this analysis, we offer insights into the development and evaluation of PET ligands. Our review concludes that further research and development in this field hold great promise for discovering effective treatments for neurological disorders.
Collapse
Affiliation(s)
- Junfeng Wang
- Gordon Center for Medical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Massachusetts, 02114, USA
| | - Yingbo Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Georges El Fakhri
- PET Center, School of Medicine, Yale University, Connecticut, 06520, USA
| |
Collapse
|
2
|
Wang Z, Li B, Wang J, Wang L. Unexpected Intermolecular C-H···O Hydrogen Bonds and 1H NMR Chemical Shifts in a Key Linker for Fluorine-18 Labeling of Dimeric Drugs. J Phys Chem B 2024; 128:5454-5462. [PMID: 38807468 PMCID: PMC11298158 DOI: 10.1021/acs.jpcb.4c01671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
The compound 2-{[(trifluoromethyl)sulfonyl]oxy}propane-1,3-diyl bis(4-methylbenzenesulfonate) (TPB) is a crucial intermediate in the synthesis of 18F-radiolabeled cromolyn derivatives. In this work, we combine 1H NMR spectroscopy, X-ray crystallography, ab initio molecular dynamics, and NMR calculations to examine the structure, interactions, and solvation dynamics of the TPB molecule. In CDCl3, the CH2 groups within its glyceryl-derived linker exhibit a single set of proton signals in the 1H NMR measurements. However, when TPB is dissolved in DMSO-d6, distinct splitting patterns emerge despite its seemingly symmetric chemical structure. Crystallographic analysis further unveils the absence of overall symmetry in its three-dimensional arrangement. To elucidate these unique NMR features, we carry out ab initio molecular dynamics simulations and characterize the solvation structures and dynamics of TPB in CHCl3 and DMSO solutions. In contrast to the predominantly nonpolar nature of the CHCl3 solvents, DMSO directly participates in C-H···O hydrogen-bonding interactions with the solute molecule, leading to the splitting of its -CH2 chemical shifts into two distinct distributions. The comprehensive understanding of the structure and solvation interactions of TPB provides essential insights into its application in the radiofluorination reactions of cromolyn derivatives and holds promise for the future development of radiolabeled dimeric drugs.
Collapse
Affiliation(s)
- Zelin Wang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Bo Li
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Junfeng Wang
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Lu Wang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States
| |
Collapse
|
3
|
Deng X, Zhu X. Recent Advances of S- 18F Radiochemistry for Positron Emission Tomography. ACS OMEGA 2023; 8:37720-37730. [PMID: 37867643 PMCID: PMC10586020 DOI: 10.1021/acsomega.3c05594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023]
Abstract
The click chemistry of sulfur(VI) fluoride exchange (SuFEx) has facilitated the widespread application of sulfur-fluoride compounds such as sulfonyl fluorides, fluorosulfates, and sulfamoyl fluorides in various fields, especially in the development of 18F ligands for PET (positron emission tomography) imaging. In recent years, the prominent progress of sulfur-[18F]fluoride compounds has been achieved through the combination of 18F and sulfur-fluoride chemistry. These compounds serve as potential 18F tracers, 18F synthons, and reagents for 18F-fluorination, thereby complementing the range of 18F ligands, typically C-18F structures, used in PET studies. This review aims to provide an overview of S-18F labeling reactions through examples of relevant 18F compounds and highlight the advancements and breakthroughs achieved in the past decade.
Collapse
Affiliation(s)
- Xiaoyun Deng
- Department of Nuclear Medicine,
Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, China
| | - Xiaohua Zhu
- Department of Nuclear Medicine,
Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030, China
| |
Collapse
|
4
|
Cools R, Kerkhofs K, Leitao RCF, Bormans G. Preclinical Evaluation of Novel PET Probes for Dementia. Semin Nucl Med 2023; 53:599-629. [PMID: 37149435 DOI: 10.1053/j.semnuclmed.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/24/2023] [Indexed: 05/08/2023]
Abstract
The development of novel PET imaging agents that selectively bind specific dementia-related targets can contribute significantly to accurate, differential and early diagnosis of dementia causing diseases and support the development of therapeutic agents. Consequently, in recent years there has been a growing body of literature describing the development and evaluation of potential new promising PET tracers for dementia. This review article provides a comprehensive overview of novel dementia PET probes under development, classified by their target, and pinpoints their preclinical evaluation pathway, typically involving in silico, in vitro and ex/in vivo evaluation. Specific target-associated challenges and pitfalls, requiring extensive and well-designed preclinical experimental evaluation assays to enable successful clinical translation and avoid shortcomings observed for previously developed 'well-established' dementia PET tracers are highlighted in this review.
Collapse
Affiliation(s)
- Romy Cools
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Kobe Kerkhofs
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium; NURA, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Renan C F Leitao
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
| |
Collapse
|
5
|
Moon SH, El Fakhri G, Zhang Z, Brownell AL, Wang J. Fully Automated Radiosynthesis of [ 18F]mG4P027 for mGluR4 Imaging. IRADIOLOGY 2023; 1:120-127. [PMID: 37496513 PMCID: PMC10371389 DOI: 10.1002/ird3.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 05/18/2023] [Indexed: 07/28/2023]
Abstract
Fluorine-18 labeled N-(4-chloro-3-(((fluoro-18F)methyl-d2)thio)phenyl)picolinamide, [18F]mG4P027, is a potent positron emission tomography (PET) radiotracer for metabotropic glutamate receptor 4 (mGluR4). Our previous in vitro and in vivo evaluations have demonstrated that this tracer is promising for further translational studies. To automate the radiosynthesis of [18F]mG4P027, significant modifications were made to the manual process by carefully examining this process and addressing the root causes of the challenges associated with its automation. We successfully implemented its automated radiosynthesis using the TRACERlab FX2N module and consequently, obtained a high-purity radiolabeled [18F]mG4P027 in high yield, meeting the requirements for future human studies.
Collapse
Affiliation(s)
- Sung-Hyun Moon
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Zhaoda Zhang
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Anna-Liisa Brownell
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| | - Junfeng Wang
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 (USA)
| |
Collapse
|
6
|
Wang J, Moon SH, Cleary MB, Shoup TM, El Fakhri G, Zhang Z, Brownell AL. Detailed radiosynthesis of [ 18 F]mG4P027 as a positron emission tomography radiotracer for mGluR4. J Labelled Comp Radiopharm 2023; 66:34-40. [PMID: 36593743 PMCID: PMC9985952 DOI: 10.1002/jlcr.4011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/25/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023]
Abstract
We report here the detailed radiosynthesis of [18 F]mG4P027, a metabotropic glutamate receptor 4 (mGluR4) PET radiotracer, which showed superior properties to the currently reported mGluR4 radiotracers. The radiosynthesis in the automated system has been challenging, therefore we disclose here the major limiting factors for the synthesis via step-by-step examination. And we hope this thorough study will help its automation for human use in the future.
Collapse
Affiliation(s)
| | | | - Michael B. Cleary
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114 (USA)
| | | | | | - Zhaoda Zhang
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114 (USA)
| | | |
Collapse
|
7
|
Doller D, Bespalov A, Miller R, Pietraszek M, Kalinichev M. A case study of foliglurax, the first clinical mGluR4 PAM for symptomatic treatment of Parkinson's disease: translational gaps or a failing industry innovation model? Expert Opin Investig Drugs 2020; 29:1323-1338. [PMID: 33074728 DOI: 10.1080/13543784.2020.1839047] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Approximately 40% of Parkinson's disease (PD) patients that take mostly dopamine receptor agonists for motor fluctuations, experience the return of symptoms between regular doses. This is a phenomenon known as 'OFF periods.' Positive allosteric modulators (PAMs) of metabotropic glutamate receptor 4 (mGluR4) are a promising non-dopaminergic mechanism with potential to address the unmet need of patients suffering from OFF periods. Foliglurax is the first mGluR4 PAM that has advanced into clinical testing in PD patients. AREAS COVERED We summarize the chemistry, pharmacokinetics, and preclinical pharmacology of foliglurax. Translational PET imaging studies, clinical efficacy data, and a competitive landscape analysis of available therapies are presented to the readers. In this Perspective article, foliglurax is used as a case study to illustrate the inherent R&D challenges that companies face when developing drugs. These challenges include the delivery of drugs acting through novel mechanisms, long-term scientific investment, and commercial success and shorter-term positive financial returns. EXPERT OPINION Failure to meet the primary and secondary endpoints in a Phase 2 study led Lundbeck to discontinue the development of foliglurax. Understanding the evidence supporting compound progression into Phase 2 will enable the proper assessment of the therapeutic potential of mGluR4 PAMs.
Collapse
Affiliation(s)
| | - Anton Bespalov
- Partnership for Assessment and Accreditation of Scientific Practice , Heidelberg, Germany.,Valdman Institute of Pharmacology, Pavlov Medical University , St. Petersburg, Russia
| | - Rob Miller
- Ventral Stream Consulting LLC ., IL, USA
| | - Malgorzata Pietraszek
- Partnership for Assessment and Accreditation of Scientific Practice , Heidelberg, Germany
| | | |
Collapse
|