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Matloka M, Janowska S, Pankiewicz P, Kokhanovska S, Kos T, Hołuj M, Rutkowska-Wlodarczyk I, Abramski K, Janicka M, Jakubowski P, Świątkiewicz M, Welniak-Kaminska M, Hucz-Kalitowska J, Dera P, Bojarski L, Grieb P, Popik P, Wieczorek M, Pieczykolan J. A PDE10A inhibitor CPL500036 is a novel agent modulating striatal function devoid of most neuroleptic side-effects. Front Pharmacol 2022; 13:999685. [PMID: 36438799 PMCID: PMC9681820 DOI: 10.3389/fphar.2022.999685] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/24/2022] [Indexed: 01/04/2024] Open
Abstract
Background: Phosphodiesterase 10A (PDE10A) is expressed almost exclusively in the striatum and its inhibition is suggested to offer potential treatment in disorders associated with basal ganglia. We evaluated the selectivity, cytotoxicity, genotoxicity, pharmacokinetics and potential adverse effects of a novel PDE10A inhibitor, CPL500036, in vivo. Methods: The potency of CPL500036 was demonstrated by microfluidic technology, and selectivity was investigated in a radioligand binding assay against 44 targets. Cardiotoxicity in vitro was evaluated in human ether-a-go-go related gene (hERG)-potassium channel-overexpressing cells by the patch-clamp method and by assessing key parameters in 3D cardiac spheroids. Cytotoxicity was determined in H1299, HepG2 and SH-SY5Y cell lines. The Ames test was used for genotoxicity analyses. During in vivo studies, CPL500036 was administered by oral gavage. CPL500036 exposure were determined by liquid chromatography-tandem mass spectrometry and plasma protein binding was assessed. The bar test was employed to assess catalepsy. Prolactin and glucose levels in rat blood were measured by ELISAs and glucometers, respectively. Cardiovascular safety in vivo was investigated in dogs using a telemetry method. Results: CPL500036 inhibited PDE10A at an IC50 of 1 nM, and interacted only with the muscarinic M2 receptor as a negative allosteric modulator with an IC50 of 9.2 µM. Despite inhibiting hERG tail current at an IC25 of 3.2 μM, cardiovascular adverse effects were not observed in human cardiac 3D spheroids or in vivo. Cytotoxicity in vitro was observed only at > 60 μM and genotoxicity was not recorded during the Ames test. CPL500036 presented good bioavailability and penetration into the brain. CPL500036 elicited catalepsy at 0.6 mg/kg, but hyperprolactinemia or hyperglycemic effects were not observed in doses up to 3 mg/kg. Conclusion: CPL500036 is a potent, selective and orally bioavailable PDE10A inhibitor with a good safety profile distinct from marketed antipsychotics. CPL500036 may be a compelling drug candidate.
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Affiliation(s)
| | | | | | | | - Tomasz Kos
- Department of Behavioral Neuroscience and Drug Development, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Małgorzata Hołuj
- Department of Behavioral Neuroscience and Drug Development, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | | | | | | | | | - Maciej Świątkiewicz
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | | | | | | | | | - Paweł Grieb
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Piotr Popik
- Department of Behavioral Neuroscience and Drug Development, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
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Xiao Z, Wei H, Xu Y, Haider A, Wei J, Yuan S, Rong J, Zhao C, Li G, Zhang W, Chen H, Li Y, Zhang L, Sun J, Zhang S, Luo HB, Yan S, Cai Q, Hou L, Che C, Liang SH, Wang L. Discovery of a highly specific 18F-labeled PET ligand for phosphodiesterase 10A enabled by novel spirocyclic iodonium ylide radiofluorination. Acta Pharm Sin B 2022; 12:1963-1975. [PMID: 35847497 PMCID: PMC9279629 DOI: 10.1016/j.apsb.2021.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/30/2021] [Accepted: 10/20/2021] [Indexed: 12/14/2022] Open
Abstract
As a member of cyclic nucleotide phosphodiesterase (PDE) enzyme family, PDE10A is in charge of the degradation of cyclic adenosine (cAMP) and guanosine monophosphates (cGMP). While PDE10A is primarily expressed in the medium spiny neurons of the striatum, it has been implicated in a variety of neurological disorders. Indeed, inhibition of PDE10A has proven to be of potential use for the treatment of central nervous system (CNS) pathologies caused by dysfunction of the basal ganglia–of which the striatum constitutes the largest component. A PDE10A-targeted positron emission tomography (PET) radioligand would enable a better assessment of the pathophysiologic role of PDE10A, as well as confirm the relationship between target occupancy and administrated dose of a given drug candidate, thus accelerating the development of effective PDE10A inhibitors. In this study, we designed and synthesized a novel 18F-aryl PDE10A PET radioligand, codenamed [18F]P10A-1910 ([18F]9), in high radiochemical yield and molar activity via spirocyclic iodonium ylide-mediated radiofluorination. [18F]9 possessed good in vitro binding affinity (IC50 = 2.1 nmol/L) and selectivity towards PDE10A. Further, [18F]9 exhibited reasonable lipophilicity (logD = 3.50) and brain permeability (Papp > 10 × 10−6 cm/s in MDCK-MDR1 cells). PET imaging studies of [18F]9 revealed high striatal uptake and excellent in vivo specificity with reversible tracer kinetics. Preclinical studies in rodents revealed an improved plasma and brain stability of [18F]9 when compared to the current reference standard for PDE10A-targeted PET, [18F]MNI659. Further, dose–response experiments with a series of escalating doses of PDE10A inhibitor 1 in rhesus monkey brains confirmed the utility of [18F]9 for evaluating target occupancy in vivo in higher species. In conclusion, our results indicated that [18F]9 is a promising PDE10A PET radioligand for clinical translation.
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Affiliation(s)
- Zhiwei Xiao
- 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
| | - Huiyi Wei
- 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
| | - Yi Xu
- Department of Cardiology, the First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Ahmed Haider
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
| | - Junjie Wei
- 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
| | - Shiyu Yuan
- 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
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
| | - Chunyu Zhao
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, 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
| | - Weibin Zhang
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Huangcan Chen
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Yuefeng Li
- Guangdong Landau Biotechnology Co. Ltd., Guangzhou 510555, China
| | - Lingling Zhang
- 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
| | - Jiyun Sun
- 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
| | - Shaojuan Zhang
- 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
| | - Hai-Bin Luo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou 570228, China
| | - Sen Yan
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, 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
| | - 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
| | - Chao Che
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
- Corresponding authors. Tel./fax: +86 755 26032530 (Chao Che), +1 617 7266165 (Steven H. Liang), +86 20 38688692 (Lu Wang).
| | - Steven H. Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
- Corresponding authors. Tel./fax: +86 755 26032530 (Chao Che), +1 617 7266165 (Steven H. Liang), +86 20 38688692 (Lu Wang).
| | - 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
- Corresponding authors. Tel./fax: +86 755 26032530 (Chao Che), +1 617 7266165 (Steven H. Liang), +86 20 38688692 (Lu Wang).
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Hou Y, Wren A, Mylarapu N, Browning K, Islam BN, Wang R, Vega KJ, Browning DD. Inhibition of Colon Cancer Cell Growth by Phosphodiesterase Inhibitors Is Independent of cGMP Signaling. J Pharmacol Exp Ther 2022; 381:42-53. [PMID: 35110391 PMCID: PMC8998686 DOI: 10.1124/jpet.121.001075] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 11/22/2022] Open
Abstract
There is growing interest in the potential use of phosphodiesterase (PDE) inhibitors for colorectal cancer (CRC) prevention and treatment. The present study has tested the idea that PDE inhibitors inhibit growth and viability of CRC cell lines by increasing cyclic guanosine monophosphate (cGMP) and activating cGMP-dependent protein kinase (PKG). Colon cancer cell lines and those with ectopic PKG2 expression were treated with membrane-permeable 8Br-cGMP or inhibitors of PDE5, PDE9, and PDE10a. Levels of cGMP capable of activating PKG were measured by immunoblotting for phosphorylation of vasodilator-stimulated phosphoprotein (VASP). The effects of treatment on CRC cell proliferation and death were measured using hemocytometry with trypan blue. Treatment with 8Br-cGMP had no effect on CRC cell proliferation or death. Endogenous PKG activity was undetectable in any of the CRC cells, but expression of ectopic PKG2 conferred modest inhibition of proliferation but did not affect cell death. Extremely high concentrations of all the PDE inhibitors reduced proliferation in CRC cell lines, but none of them increased cGMP levels, and the effect was independent of PKG expression. The inability of the PDE inhibitors to increase cGMP was due to the lack of endogenous cGMP generating machinery. In conclusion, PDE inhibitors that target cGMP only reduce CRC growth at clinically unachievable concentrations, and do so independent of cGMP signaling through PKG. SIGNIFICANCE STATEMENT: A large number of in vitro studies have reported that PDE inhibitors block growth of colon cancer cells by activating cGMP signaling, and that these drugs might be useful for cancer treatment. Our results show that these drugs do not activate cGMP signaling in colon cancer cells due to a lack of endogenous guanylyl cyclase activity, and that growth inhibition is due to toxic effects of clinically unobtainable drug concentrations.
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Affiliation(s)
- Yali Hou
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
| | - Alexis Wren
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
| | - Namratha Mylarapu
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
| | - Kaylin Browning
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
| | - Bianca N Islam
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
| | - Rui Wang
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
| | - Kenneth J Vega
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
| | - Darren D Browning
- Department of Biochemistry and Molecular Biology (Y.H., A.W., N.M., K.B., D.D.B.) and Department of Medicine, Section of Gastroenterology and Hepatology (K.J.V.), Augusta University, Augusta, Georgia; and Department of Internal Medicine (B.N.I.) and Department of Surgery (R.W.), Case Western Reserve University, Cleveland, Ohio
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4
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Lee KJ, Chang WCL, Chen X, Valiyaveettil J, Ramirez-Alcantara V, Gavin E, Musiyenko A, Madeira da Silva L, Annamdevula NS, Leavesley SJ, Ward A, Mattox T, Lindsey AS, Andrews J, Zhu B, Wood C, Neese A, Nguyen A, Berry K, Maxuitenko Y, Moyer MP, Nurmemmedov E, Gorman G, Coward L, Zhou G, Keeton AB, Cooper HS, Clapper ML, Piazza GA. Suppression of Colon Tumorigenesis in Mutant Apc Mice by a Novel PDE10 Inhibitor that Reduces Oncogenic β-Catenin. Cancer Prev Res (Phila) 2021; 14:995-1008. [PMID: 34584001 DOI: 10.1158/1940-6207.capr-21-0208] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/12/2021] [Accepted: 09/21/2021] [Indexed: 11/16/2022]
Abstract
Previous studies have reported that phosphodiesterase 10A (PDE10) is overexpressed in colon epithelium during early stages of colon tumorigenesis and essential for colon cancer cell growth. Here we describe a novel non-COX inhibitory derivative of the anti-inflammatory drug, sulindac, with selective PDE10 inhibitory activity, ADT 061. ADT 061 potently inhibited the growth of colon cancer cells expressing high levels of PDE10, but not normal colonocytes that do not express PDE10. The concentration range by which ADT 061 inhibited colon cancer cell growth was identical to concentrations that inhibit recombinant PDE10. ADT 061 inhibited PDE10 by a competitive mechanism and did not affect the activity of other PDE isozymes at concentrations that inhibit colon cancer cell growth. Treatment of colon cancer cells with ADT 061 activated cGMP/PKG signaling, induced phosphorylation of oncogenic β-catenin, inhibited Wnt-induced nuclear translocation of β-catenin, and suppressed TCF/LEF transcription at concentrations that inhibit cancer cell growth. Oral administration of ADT 061 resulted in high concentrations in the colon mucosa and significantly suppressed the formation of colon adenomas in the Apc+/min-FCCC mouse model of colorectal cancer without discernable toxicity. These results support the development of ADT 061 for the treatment or prevention of adenomas in individuals at risk of developing colorectal cancer. PREVENTION RELEVANCE: PDE10 is overexpressed in colon tumors whereby inhibition activates cGMP/PKG signaling and suppresses Wnt/β-catenin transcription to selectively induce apoptosis of colon cancer cells. ADT 061 is a novel PDE10 inhibitor that shows promising cancer chemopreventive activity and tolerance in a mouse model of colon cancer.
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Affiliation(s)
- Kevin J Lee
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Wen-Chi L Chang
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Xi Chen
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Jacob Valiyaveettil
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | | | - Elaine Gavin
- Gynecologic Oncology Research Division, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Alla Musiyenko
- Gynecologic Oncology Research Division, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Luciana Madeira da Silva
- Gynecologic Oncology Research Division, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Naga S Annamdevula
- Department of Chemical and Biomedical Engineering, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Silas J Leavesley
- Department of Chemical and Biomedical Engineering, University of South Alabama, Mobile, Alabama.,Center for Lung Biology, University of South Alabama, Mobile, Alabama.,Department of Pharmacology, University of South Alabama, Mobile, Alabama
| | - Antonio Ward
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Tyler Mattox
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Ashley S Lindsey
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Joel Andrews
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Bing Zhu
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Charles Wood
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Ashleigh Neese
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Ashley Nguyen
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Kristy Berry
- Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama
| | - Yulia Maxuitenko
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama
| | | | | | | | | | - Gang Zhou
- Georgia Cancer Center, Augusta University, Augusta, Georgia
| | - Adam B Keeton
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama
| | - Harry S Cooper
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Margie L Clapper
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Gary A Piazza
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama.
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Nathan PJ, Bakker G. Lessons learned from using fMRI in the early clinical development of a mu-opioid receptor antagonist for disorders of compulsive consumption. Psychopharmacology (Berl) 2021; 238:1255-1263. [PMID: 31900526 DOI: 10.1007/s00213-019-05427-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 12/06/2019] [Indexed: 01/23/2023]
Abstract
Functional magnetic resonance imaging (fMRI) has been widely used to gain a greater understanding of brain circuitry abnormalities in CNS disorders. fMRI has also been used to examine pharmacological modulation of brain circuity and is increasingly being used in early clinical drug development as functional pharmacodynamic index of target engagement, and to provide early indication of clinical efficacy. In this short review, we summarize data from experimental medicine and early clinical development studies of a mu-opioid receptor antagonist, GSK1521498 developed for disorders of compulsive consumption including binge eating in obesity. We demonstrate how fMRI can be used to answer important questions of early clinical drug development relating to; (1) target engagement, (2) dose response relationships, (3) differential efficacy and (4) prediction of behavioural and clinically relevant outcomes. We also highlight important methodological factors that need to be considered when conducting fMRI studies in drug development given the challenges faced with small sample sizes in Phase 1 and early proof of mechanism studies. While these data highlight the value of fMRI as a biomarker in drug development, its use for making Go/No-go decisions is still faced with challenges given the variability of responses, interpretation of brain activation changes and the limited data linking drug induced changes in brain activity to clinical or behavioural outcome. These challenges need to be addressed to fulfil the promise of fMRI as a tool in clinical drug development.
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Affiliation(s)
- Pradeep J Nathan
- Experimental Medicine (Neuroscience), Sosei Heptares, Cambridge, UK
- Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Cambridge, UK
- The Monash School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Geor Bakker
- Experimental Medicine (Neuroscience), Sosei Heptares, Cambridge, UK.
- Department of Psychiatry and Psychology, Maastricht University, Maastricht, Netherlands.
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.
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Schröder S, Scheunemann M, Wenzel B, Brust P. Challenges on Cyclic Nucleotide Phosphodiesterases Imaging with Positron Emission Tomography: Novel Radioligands and (Pre-)Clinical Insights since 2016. Int J Mol Sci 2021; 22:ijms22083832. [PMID: 33917199 PMCID: PMC8068090 DOI: 10.3390/ijms22083832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/21/2022] Open
Abstract
Cyclic nucleotide phosphodiesterases (PDEs) represent one of the key targets in the research field of intracellular signaling related to the second messenger molecules cyclic adenosine monophosphate (cAMP) and/or cyclic guanosine monophosphate (cGMP). Hence, non-invasive imaging of this enzyme class by positron emission tomography (PET) using appropriate isoform-selective PDE radioligands is gaining importance. This methodology enables the in vivo diagnosis and staging of numerous diseases associated with altered PDE density or activity in the periphery and the central nervous system as well as the translational evaluation of novel PDE inhibitors as therapeutics. In this follow-up review, we summarize the efforts in the development of novel PDE radioligands and highlight (pre-)clinical insights from PET studies using already known PDE radioligands since 2016.
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Affiliation(s)
- Susann Schröder
- Department of Research and Development, ROTOP Pharmaka Ltd., 01328 Dresden, Germany
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany; (M.S.); (B.W.); (P.B.)
- Correspondence: ; Tel.: +49-341-234-179-4631
| | - Matthias Scheunemann
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany; (M.S.); (B.W.); (P.B.)
| | - Barbara Wenzel
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany; (M.S.); (B.W.); (P.B.)
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 04318 Leipzig, Germany; (M.S.); (B.W.); (P.B.)
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Abstract
This article presents an overview of imaging agents for PET that have been applied for research and diagnostic purposes in patients affected by dementia. Classified by the target which the agents visualize, seven groups of tracers can be distinguished, namely radiopharmaceuticals for: (1) Misfolded proteins (ß-amyloid, tau, α-synuclein), (2) Neuroinflammation (overexpression of translocator protein), (3) Elements of the cholinergic system, (4) Elements of monoamine neurotransmitter systems, (5) Synaptic density, (6) Cerebral energy metabolism (glucose transport/ hexokinase), and (7) Various other proteins. This last category contains proteins involved in mechanisms underlying neuroinflammation or cognitive impairment, which may also be potential therapeutic targets. Many receptors belong to this category: AMPA, cannabinoid, colony stimulating factor 1, metabotropic glutamate receptor 1 and 5 (mGluR1, mGluR5), opioid (kappa, mu), purinergic (P2X7, P2Y12), sigma-1, sigma-2, receptor for advanced glycation endproducts, and triggering receptor expressed on myeloid cells-1, besides several enzymes: cyclooxygenase-1 and 2 (COX-1, COX-2), phosphodiesterase-5 and 10 (PDE5, PDE10), and tropomyosin receptor kinase. Significant advances in neuroimaging have been made in the last 15 years. The use of 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) for quantification of regional cerebral glucose metabolism is well-established. Three tracers for ß-amyloid plaques have been approved by the Food and Drug Administration and European Medicines Agency. Several tracers for tau neurofibrillary tangles are already applied in clinical research. Since many novel agents are in the preclinical or experimental stage of development, further advances in nuclear medicine imaging can be expected in the near future. PET studies with established tracers and tracers for novel targets may result in early diagnosis and better classification of neurodegenerative disorders and in accurate monitoring of therapy trials which involve these targets. PET data have prognostic value and may be used to assess the response of the human brain to interventions, or to select the appropriate treatment strategy for an individual patient.
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Affiliation(s)
- Aren van Waarde
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen, the Netherlands.
| | - Sofia Marcolini
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, the Netherlands
| | - Peter Paul de Deyn
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, the Netherlands; University of Antwerp, Born-Bunge Institute, Neurochemistry and Behavior, Campus Drie Eiken, Wilrijk, Belgium
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen, the Netherlands; Ghent University, Ghent, Belgium
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Menniti FS, Chappie TA, Schmidt CJ. PDE10A Inhibitors-Clinical Failure or Window Into Antipsychotic Drug Action? Front Neurosci 2021; 14:600178. [PMID: 33551724 PMCID: PMC7855852 DOI: 10.3389/fnins.2020.600178] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/21/2020] [Indexed: 01/21/2023] Open
Abstract
PDE10A, a phosphodiesterase that inactivates both cAMP and cGMP, is a unique signaling molecule in being highly and nearly exclusively expressed in striatal medium spiny neurons. These neurons dynamically integrate cortical information with dopamine-signaled value to mediate action selection among available behavioral options. Medium spiny neurons are components of either the direct or indirect striatal output pathways. Selective activation of indirect pathway medium spiny neurons by dopamine D2 receptor antagonists is putatively a key element in the mechanism of their antipsychotic efficacy. While PDE10A is expressed in all medium spiny neurons, studies in rodents indicated that PDE10A inhibition has behavioral effects in several key assays that phenocopy dopamine D2 receptor inhibition. This finding gave rise to the hypothesis that PDE10A inhibition also preferentially activates indirect pathway medium spiny neurons, a hypothesis that is consistent with electrophysiological, neurochemical, and molecular effects of PDE10A inhibitors. These data underwrote industry-wide efforts to investigate and develop PDE10A inhibitors as novel antipsychotics. Disappointingly, PDE10A inhibitors from 3 companies failed to evidence antipsychotic activity in patients with schizophrenia to the same extent as standard-of-care D2 antagonists. Given the notable similarities between PDE10A inhibitors and D2 antagonists, gaining an understanding of why only the latter class is antipsychotic affords a unique window into the basis for this therapeutic efficacy. With this in mind, we review the data on PDE10A inhibition as a step toward back-translating the limited antipsychotic efficacy of PDE10A inhibitors, hopefully to inform new efforts to develop better therapeutics to treat psychosis and schizophrenia.
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Affiliation(s)
- Frank S Menniti
- George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, United States
| | - Thomas A Chappie
- Internal Medicine Medicinal Chemistry, Pfizer Worldwide Research and Development, Cambridge, MA, United States
| | - Christopher J Schmidt
- Pfizer Innovation and Research Lab Unit, Pfizer Worldwide Research and Development, Cambridge, MA, United States
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Antipsychotic-like effects of a novel phosphodiesterase 10A inhibitor MT-3014 in rats. Pharmacol Biochem Behav 2020; 196:172972. [PMID: 32562717 DOI: 10.1016/j.pbb.2020.172972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 06/07/2020] [Accepted: 06/16/2020] [Indexed: 12/28/2022]
Abstract
Phosphodiesterase (PDE) 10A is an attractive therapeutic target for schizophrenia. Here, we investigated the antipsychotic-like effects of a novel PDE10A inhibitor, 1-({2-(7-fluoro-3-methylquinoxalin-2-yl)-5-[(3R)-3-fluoropyrrolidin-1-yl]pyrazolo[1,5-α]pyrimidin-7-yl}amino)-2-methylpropan-2-ol hydrochloride (MT-3014) in rats. MT-3014 showed a potent and selective inhibitory effect against PDE10A (IC50 = 0.357 nmol/L). Oral administration of MT-3014 (1.0-10 mg/kg) significantly increased the levels of cAMP, cGMP and cAMP response element-binding protein (CREB) phosphorylation in the rat striatum. MT-3014 decreased MK-801 (0.075 mg/kg)-induced hyperactivity (ED50 = 0.30 mg/kg) in a dose-dependent manner, although it decreased spontaneous locomotion in control rats (ED50 = 0.48 mg/kg); its effects were equivalent to those of risperidone. MT-3014 (0.3-3.0 mg/kg and 0.2 mg/kg) attenuated MK-801-induced prepulse inhibition deficits and cognitive deficits in rats, respectively, whereas risperidone attenuated MK-801-induced prepulse inhibition at only a high dose and failed to improve MK-801-induced cognitive deficits. Similar to risperidone (ID50 = 0.63 mg/kg), MT-3014 suppressed the conditioned avoidance response (ID50 = 0.32 mg/kg). Interestingly, MT-3014 did not elicit catalepsy and plasma prolactin increases at high doses. Furthermore, it also did not affect body weight. A positron emission tomography study using [11C]IMA107 showed a plasma concentration-dependent increase in brain PDE10A occupancy after oral administration of MT-3014 within the pharmacological dose range in rats. Brain PDE10A occupancy corresponding to the ID50 value in the conditioned avoidance response was approximately 60%, predicting the target occupancy in patients with schizophrenia. These results suggest that MT-3014 may be a novel antipsychotic drug, which is expected to have additional effects on cognitive impairment, without the prominent side effects associated with current atypical antipsychotics.
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Phosphodiesterase 10A Inhibitor Monotherapy Is Not an Effective Treatment of Acute Schizophrenia. J Clin Psychopharmacol 2020; 39:575-582. [PMID: 31688451 DOI: 10.1097/jcp.0000000000001128] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Current treatments for psychotic symptoms associated with schizophrenia often provide inadequate efficacy with unacceptable adverse effects. Improved therapeutics have long been a goal of research. Preclinical testing suggests that phosphodiesterase 10A (PDE10A) inhibitors may provide a novel approach to treating psychosis associated with schizophrenia. METHODS The efficacy and safety of a highly selective PDE10A inhibitor, PF-02545920, was evaluated in a phase 2 multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Eligible patients (18-65 years) with an acute exacerbation of schizophrenia were randomized 2:2:1:2 to PF-02545920 (5 or 15 mg every 12 hours [Q12H] titrated), risperidone (3 mg Q12H), or placebo for 28 days (n = 74:74:37:74). The primary objectives were to evaluate the efficacy of PF-02545920 using the Positive and Negative Syndrome Scale (PANNS) and safety/tolerability. RESULTS At day 28, PF-02545920 (either dose) was not significantly different from placebo for mean change from baseline in the PANNS total score (primary end point) or most other end points. Pharmacokinetics exposures seemed adequate for binding/inhibiting PDE10A enzyme. Risperidone was statistically different from placebo for the PANNS total score, demonstrating study sensitivity. Incidence rates for adverse events were similar among the groups. Both doses of PF-02545920 were generally well tolerated. Dystonia occurred in 1, 6, 0, and 3 patients in the PF-02545920 5 mg Q12H, PF-02545920 15 mg Q12H, risperidone, and placebo groups, respectively. CONCLUSIONS Neither dose of PF-02545920 was superior to placebo for the primary and most secondary end points. This indicates that PDE10A inhibition does not produce an antipsychotic effect in patients with acute exacerbation of schizophrenia.
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A Proof-of-Concept Study Evaluating the Phosphodiesterase 10A Inhibitor PF-02545920 in the Adjunctive Treatment of Suboptimally Controlled Symptoms of Schizophrenia. J Clin Psychopharmacol 2020; 39:318-328. [PMID: 31205187 DOI: 10.1097/jcp.0000000000001047] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Effective treatments for managing suboptimal clinical responses to current therapy for schizophrenia remain a critical unmet need. Phosphodiesterase 10A (PDE10A) inhibition represents a mechanistically novel approach to the treatment of schizophrenia, with preclinical studies suggesting improvements in partially responsive symptoms could be achieved via adjunctive use of the PDE10A inhibitor PF-02545920. Therefore, the adjunctive safety, tolerability, pharmacokinetics, and efficacy of multiple repeat doses of PF-02545920 were investigated in a phase 1b study and subsequent phase 2 study. METHODS The phase 1b study randomized 37 adult patients with stable symptomatology and stable antipsychotic regimens within 3 cohorts. Study participants received ascending doses of PF-02545920 or placebo for 10 to 18 days. The phase 2 study randomized 240 outpatients with stable symptomatology but suboptimal response to current antipsychotic regimens 1:1:1 to PF-02545920 5 mg, PF-02545920 15 mg, or placebo every 12 hours for 12 weeks. The primary efficacy end point of the phase 2 study was change in the Positive and Negative Syndrome Scale total score from baseline to week 12, with changes in other clinical assessments as secondary end points. RESULTS Treatment was well tolerated, and observed PF-02545920 exposures were within the range predicted to be adequate for demonstrating efficacy. However, no significant differences in the prespecified efficacy end points between the 2 PF-02545920 treatment arms and placebo were observed. CONCLUSIONS Current data and results of a prior monotherapy study in which PF-02545920 failed to differentiate from placebo refute the hypothesis that PDE10A inhibitors have use as antipsychotic agents for schizophrenia.
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McCluskey SP, Plisson C, Rabiner EA, Howes O. Advances in CNS PET: the state-of-the-art for new imaging targets for pathophysiology and drug development. Eur J Nucl Med Mol Imaging 2020; 47:451-489. [PMID: 31541283 PMCID: PMC6974496 DOI: 10.1007/s00259-019-04488-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE A limit on developing new treatments for a number of central nervous system (CNS) disorders has been the inadequate understanding of the in vivo pathophysiology underlying neurological and psychiatric disorders and the lack of in vivo tools to determine brain penetrance, target engagement, and relevant molecular activity of novel drugs. Molecular neuroimaging provides the tools to address this. This article aims to provide a state-of-the-art review of new PET tracers for CNS targets, focusing on developments in the last 5 years for targets recently available for in-human imaging. METHODS We provide an overview of the criteria used to evaluate PET tracers. We then used the National Institute of Mental Health Research Priorities list to identify the key CNS targets. We conducted a PubMed search (search period 1st of January 2013 to 31st of December 2018), which yielded 40 new PET tracers across 16 CNS targets which met our selectivity criteria. For each tracer, we summarised the evidence of its properties and potential for use in studies of CNS pathophysiology and drug evaluation, including its target selectivity and affinity, inter and intra-subject variability, and pharmacokinetic parameters. We also consider its potential limitations and missing characterisation data, but not specific applications in drug development. Where multiple tracers were present for a target, we provide a comparison of their properties. RESULTS AND CONCLUSIONS Our review shows that multiple new tracers have been developed for proteinopathy targets, particularly tau, as well as the purinoceptor P2X7, phosphodiesterase enzyme PDE10A, and synaptic vesicle glycoprotein 2A (SV2A), amongst others. Some of the most promising of these include 18F-MK-6240 for tau imaging, 11C-UCB-J for imaging SV2A, 11C-CURB and 11C-MK-3168 for characterisation of fatty acid amide hydrolase, 18F-FIMX for metabotropic glutamate receptor 1, and 18F-MNI-444 for imaging adenosine 2A. Our review also identifies recurrent issues within the field. Many of the tracers discussed lack in vivo blocking data, reducing confidence in selectivity. Additionally, late-stage identification of substantial off-target sites for multiple tracers highlights incomplete pre-clinical characterisation prior to translation, as well as human disease state studies carried out without confirmation of test-retest reproducibility.
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Affiliation(s)
- Stuart P McCluskey
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - Christophe Plisson
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Eugenii A Rabiner
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Oliver Howes
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
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New approach in radiometabolite analysis of positron emission tomography (PET) radioligands; lead-shielded microextraction by packed sorbent as a tool for in vivo radiometabolite analysis of [11C]SMW139 in rat plasma. Talanta 2020; 208:120449. [DOI: 10.1016/j.talanta.2019.120449] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/01/2019] [Accepted: 10/04/2019] [Indexed: 02/05/2023]
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Baillie GS, Tejeda GS, Kelly MP. Therapeutic targeting of 3',5'-cyclic nucleotide phosphodiesterases: inhibition and beyond. Nat Rev Drug Discov 2019; 18:770-796. [PMID: 31388135 PMCID: PMC6773486 DOI: 10.1038/s41573-019-0033-4] [Citation(s) in RCA: 181] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2019] [Indexed: 01/24/2023]
Abstract
Phosphodiesterases (PDEs), enzymes that degrade 3',5'-cyclic nucleotides, are being pursued as therapeutic targets for several diseases, including those affecting the nervous system, the cardiovascular system, fertility, immunity, cancer and metabolism. Clinical development programmes have focused exclusively on catalytic inhibition, which continues to be a strong focus of ongoing drug discovery efforts. However, emerging evidence supports novel strategies to therapeutically target PDE function, including enhancing catalytic activity, normalizing altered compartmentalization and modulating post-translational modifications, as well as the potential use of PDEs as disease biomarkers. Importantly, a more refined appreciation of the intramolecular mechanisms regulating PDE function and trafficking is emerging, making these pioneering drug discovery efforts tractable.
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Affiliation(s)
- George S Baillie
- Institute of Cardiovascular and Medical Science, University of Glasgow, Glasgow, UK
| | - Gonzalo S Tejeda
- Institute of Cardiovascular and Medical Science, University of Glasgow, Glasgow, UK
| | - Michy P Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA.
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Gu G, Scott T, Yan Y, Warren N, Zhang A, Tabatabaei A, Xu H, Aertgeerts K, Gomez L, Morse A, Li YW, Breitenbucher JG, Massari E, Vivian J, Danks A. Target Engagement of a Phosphodiesterase 2A Inhibitor Affecting Long-Term Memory in the Rat. J Pharmacol Exp Ther 2019; 370:399-407. [DOI: 10.1124/jpet.118.255851] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 06/24/2019] [Indexed: 12/13/2022] Open
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Zeun P, Scahill RI, Tabrizi SJ, Wild EJ. Fluid and imaging biomarkers for Huntington's disease. Mol Cell Neurosci 2019; 97:67-80. [PMID: 30807825 DOI: 10.1016/j.mcn.2019.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/25/2019] [Accepted: 02/12/2019] [Indexed: 01/18/2023] Open
Abstract
Huntington's disease is a chronic progressive neurodegenerative condition for which there is no disease-modifying treatment. The known genetic cause of Huntington's disease makes it possible to identify individuals destined to develop the disease and instigate treatments before the onset of symptoms. Multiple trials are already underway that target the cause of HD, yet clinical measures are often insensitive to change over typical clinical trial duration. Robust biomarkers of drug target engagement, disease severity and progression are required to evaluate the efficacy of treatments and concerted efforts are underway to achieve this. Biofluid biomarkers have potential advantages of direct quantification of biological processes at the molecular level, whilst imaging biomarkers can quantify related changes at a structural level in the brain. The most robust biofluid and imaging biomarkers can offer complementary information, providing a more comprehensive evaluation of disease stage and progression to inform clinical trial design and endpoints.
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Affiliation(s)
- Paul Zeun
- Huntington's Disease Centre, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
| | - Rachael I Scahill
- Huntington's Disease Centre, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
| | - Sarah J Tabrizi
- Huntington's Disease Centre, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
| | - Edward J Wild
- Huntington's Disease Centre, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
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PET Radioligands for imaging of the PDE10A in human: current status. Neurosci Lett 2019; 691:11-17. [DOI: 10.1016/j.neulet.2018.08.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 07/19/2018] [Accepted: 08/08/2018] [Indexed: 01/26/2023]
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Mori W, Yamasaki T, Fujinaga M, Ogawa M, Zhang Y, Hatori A, Xie L, Kumata K, Wakizaka H, Kurihara Y, Ohkubo T, Nengaki N, Zhang MR. Development of 2-(2-(3-(4-([ 18F]Fluoromethoxy- d 2)phenyl)-7-methyl-4-oxo-3,4-dihydroquinazolin-2-yl)ethyl)-4-isopropoxyisoindoline-1,3-dione for Positron-Emission-Tomography Imaging of Phosphodiesterase 10A in the Brain. J Med Chem 2018; 62:688-698. [PMID: 30516998 DOI: 10.1021/acs.jmedchem.8b01366] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Phosphodiesterase 10A (PDE10A) is a newly identified therapeutic target for central-nervous-system disorders. 2-(2-(3-(4-([18F]Fluoroethoxy)phenyl)-4-oxo-3,4-dihydroquinazolin-2-yl)ethyl)-4-isopropoxyisoindoline-1,3-dione ([18F]MNI-659, [18F]5) is a useful positron-emission-tomography (PET) ligand for imaging of PDE10A in the human brain. However, the radiolabeled metabolite of [18F]5 can accumulate in the brain. In this study, using [18F]5 as a lead compound, we designed four new 18F-labeled ligands ([18F]6-9) to find one more suitable than [18F]5. Of these, 2-(2-(3-(4-([18F]fluoromethoxy- d2)phenyl)-4-oxo-3,4-dihydroquinazolin-2-yl)ethyl)-4-isopropoxyisoindoline-1,3-dione ([18F]9) exhibited high in vitro binding affinity ( Ki = 2.9 nM) to PDE10A and suitable lipophilicity (log D = 2.2). In PET studies, the binding potential (BPND) of [18F]9 (5.8) to PDE10A in the striatum of rat brains was significantly higher than that of [18F]5 (4.6). Furthermore, metabolite analysis showed much lower levels of contamination with radiolabeled metabolites in the brains of rats given [18F]9 than in those given [18F]5. In conclusion, [18F]9 is a useful PET ligand for PDE10A imaging in brain.
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Affiliation(s)
| | | | | | - Masanao Ogawa
- SHI Accelerator Service, Ltd. , 1-17-6 Osaki , Shinagawa-ku, Tokyo 141-0032 , Japan
| | | | | | | | | | | | - Yusuke Kurihara
- SHI Accelerator Service, Ltd. , 1-17-6 Osaki , Shinagawa-ku, Tokyo 141-0032 , Japan
| | - Takayuki Ohkubo
- SHI Accelerator Service, Ltd. , 1-17-6 Osaki , Shinagawa-ku, Tokyo 141-0032 , Japan
| | - Nobuki Nengaki
- SHI Accelerator Service, Ltd. , 1-17-6 Osaki , Shinagawa-ku, Tokyo 141-0032 , Japan
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Mori W, Takei M, Furutsuka K, Fujinaga M, Kumata K, Muto M, Ohkubo T, Hashimoto H, Tamagnan G, Higuchi M, Kawamura K, Zhang MR. Comparison between [ 18F]fluorination and [ 18F]fluoroethylation reactions for the synthesis of the PDE10A PET radiotracer [ 18F]MNI-659. Nucl Med Biol 2017; 55:12-18. [PMID: 28972915 DOI: 10.1016/j.nucmedbio.2017.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/04/2017] [Accepted: 08/15/2017] [Indexed: 12/20/2022]
Abstract
INTRODUCTION 2-(2-(3-(4-(2-[18F]Fluoroethoxy)phenyl)-7-methyl-4-oxo-3,4-dihydroquinazolin-2-yl)ethyl)-4-isopropoxyisoindoline-1,3-dione ([18F]MNI-659, [18F]1) is a useful PET radiotracer for imaging phosphodiesterase 10A (PDE10A) in human brain. [18F]1 has been previously prepared by direct [18F]fluorination of a tosylate precursor 2 with [18F]F-. The aim of this study was to determine the conditions for the [18F]fluorination reaction to obtain [18F]1 of high quality and with sufficient radioactivity for clinical use in our institute. Moreover, we synthesized [18F]1 by [18F]fluoroethylation of a phenol precursor 3 with [18F]fluoroethyl bromide ([18F]FEtBr), and the outcomes of [18F]fluorination and [18F]fluoroethylation were compared. METHODS We performed the automated synthesis of [18F]1 by [18F]fluorination and [18F]fluoroethylation using a multi-purpose synthesizer. We determined the amounts of tosylate precursor 2 and potassium carbonate as well as the reaction temperature for direct [18F]fluorination. RESULTS The efficiency of the [18F]fluorination reaction was strongly affected by the amount of 2 and potassium carbonate. Under the determined reaction conditions, [18F]1 with 0.82±0.2GBq was obtained in 13.6%±3.3% radiochemical yield (n=8, decay-corrected to EOB and based on [18F]F-) at EOS, starting from 11.5±0.4GBq of cyclotron-produced [18F]F-. On the other hand, the [18F]fluoroethylation of 3 with [18F]FEtBr produced [18F]1 with 1.0±0.2GBq and in 22.5±2.5 % radiochemical yields (n=7, decay-corrected to EOB and based on [18F]F-) at EOS, starting from 7.4GBq of cyclotron-produced [18F]F-. Clearly, [18F]fluoroethylation resulted in a higher radiochemical yield of [18F]1 than [18F]fluorination. CONCLUSION [18F]1 of high quality and with sufficient radioactivity was successfully radiosynthesized by two methods. [18F]1 synthesized by direct [18F]fluorination has been approved and will be provided for clinical use in our institute.
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Affiliation(s)
- Wakana Mori
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Makoto Takei
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Kenji Furutsuka
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Masayuki Fujinaga
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Katsushi Kumata
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Masatoshi Muto
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; Tokyo Nuclear Services Ltd., Tokyo 110-0016, Japan
| | - Takayuki Ohkubo
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Hiroki Hashimoto
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | | | - Makoto Higuchi
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Kazunori Kawamura
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Ming-Rong Zhang
- National Institute of Radiological Science, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan.
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