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Singh K, Ngo A, Keerthisinghe OV, Patel KK, Liang C, Mukherjee J. Synthesis and Evaluation of Compound Targeting α7 and β2 Subunits in Nicotinic Acetylcholinergic Receptor. Molecules 2023; 28:8128. [PMID: 38138615 PMCID: PMC10745926 DOI: 10.3390/molecules28248128] [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: 11/19/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are involved in various central nervous system functions and have also been implicated in several neurodegenerative disorders. The heteromeric α4β2* and homomeric α7 are two major nAChR subtypes which have been studied in the brain using positron emission tomography (PET). Our comparative autoradiographic studies of the two receptor types in the mouse and rat brains show major differences in the thalamus (α4β2* >> α7), hippocampus (α7 >> α4β2*), and subiculum (α4β2* >> α7). A relatively newer heteromeric α7β2 nAChR subtype has been identified in the brain which may have a greater role in neurodegeneration. We report the development of KS7 (3-(2-(S)-azetidinylmethoxy)-5-(1,4-diaza-bicyclo[3.2.2]nonane)pyridine) which incorporates structural features of Nifzetidine (high affinity for α4β2* nAChR) and ASEM (high affinity for α7 nAChR) in an effort to target α7 and β2 subunits in α7β2 nAChR. KS7 exhibited higher affinities (IC50 = 50 to 172 nM) for [3H]cytisine radiolabeled sites and weaker affinities (IC50 = 10 μM) for [125I]-α-bungarotoxin radiolabeled rat brain sites in several brain regions. The weaker affinity of KS7 to α7 nAChR may suggest lack of binding at the α7 subunit of α7β2 nAChR. A radiolabeled derivative of KS7 may be required to identify any specific binding to brain regions suggested to contain α7β2 nAChR.
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Affiliation(s)
| | | | | | | | | | - Jogeshwar Mukherjee
- Preclinical Imaging, Department of Radiological Sciences, University of California-Irvine, Irvine, CA 92697, USA; (K.S.); (A.N.); (O.V.K.); (K.K.P.); (C.L.)
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2
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Fontana IC, Kumar A, Nordberg A. The role of astrocytic α7 nicotinic acetylcholine receptors in Alzheimer disease. Nat Rev Neurol 2023; 19:278-288. [PMID: 36977843 DOI: 10.1038/s41582-023-00792-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 03/30/2023]
Abstract
The ongoing search for therapeutic interventions in Alzheimer disease (AD) has highlighted the complexity of this condition and the need for additional biomarkers, beyond amyloid-β (Aβ) and tau, to improve clinical assessment. Astrocytes are brain cells that control metabolic and redox homeostasis, among other functions, and are emerging as an important focus of AD research owing to their swift response to brain pathology in the initial stages of the disease. Reactive astrogliosis - the morphological, molecular and functional transformation of astrocytes during disease - has been implicated in AD progression, and the definition of new astrocytic biomarkers could help to deepen our understanding of reactive astrogliosis along the AD continuum. As we highlight in this Review, one promising biomarker candidate is the astrocytic α7 nicotinic acetylcholine receptor (α7nAChR), upregulation of which correlates with Aβ pathology in the brain of individuals with AD. We revisit the past two decades of research into astrocytic α7nAChRs to shed light on their roles in the context of AD pathology and biomarkers. We discuss the involvement of astrocytic α7nAChRs in the instigation and potentiation of early Aβ pathology and explore their potential as a target for future reactive astrocyte-based therapeutics and imaging biomarkers in AD.
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Affiliation(s)
- Igor C Fontana
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Amit Kumar
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
- Theme Inflammation and Aging, Karolinska University Hospital, Stockholm, Sweden.
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Vlad IM, Nuță DC, Ancuceanu RV, Costea T, Coanda M, Popa M, Marutescu LG, Zarafu I, Ionita P, Pirvu CED, Bleotu C, Chifiriuc MC, Limban C. Insights into the Microbicidal, Antibiofilm, Antioxidant and Toxicity Profile of New O-Aryl-Carbamoyl-Oxymino-Fluorene Derivatives. Int J Mol Sci 2023; 24:ijms24087020. [PMID: 37108183 PMCID: PMC10138554 DOI: 10.3390/ijms24087020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/04/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
The unprecedented increase in microbial resistance rates to all current drugs raises an acute need for the design of more effective antimicrobial strategies. Moreover, the importance of oxidative stress due to chronic inflammation in infections with resistant bacteria represents a key factor for the development of new antibacterial agents with potential antioxidant effects. Thus, the purpose of this study was to bioevaluate new O-aryl-carbamoyl-oxymino-fluorene derivatives for their potential use against infectious diseases. With this aim, their antimicrobial effect was evaluated using quantitative assays (minimum inhibitory/bactericidal/biofilms inhibitory concentrations) (MIC/MBC/MBIC), the obtained values being 0.156-10/0.312-10/0.009-1.25 mg/mL), while some of the involved mechanisms (i.e., membrane depolarization) were investigated by flow cytometry. The antioxidant activity was evaluated by studying the scavenger capacity of DPPH and ABTS•+ radicals and the toxicity was tested in vitro on three cell lines and in vivo on the crustacean Artemia franciscana Kellog. The four compounds derived from 9H-fluoren-9-one oxime proved to exhibit promising antimicrobial features and particularly, a significant antibiofilm activity. The presence of chlorine induced an electron-withdrawing effect, favoring the anti-Staphylococcus aureus and that of the methyl group exhibited a +I effect of enhancing the anti-Candida albicans activity. The IC50 values calculated in the two toxicity assays revealed similar values and the potential of these compounds to inhibit the proliferation of tumoral cells. Taken together, all these data demonstrate the potential of the tested compounds to be further used for the development of novel antimicrobial and anticancer agents.
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Affiliation(s)
- Ilinca Margareta Vlad
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 020956 Bucharest, Romania
| | - Diana Camelia Nuță
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 020956 Bucharest, Romania
| | - Robert Viorel Ancuceanu
- Department of Pharmaceutical Botany and Cell Biology, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 6 TraianVuia, 020956 Bucharest, Romania
| | - Teodora Costea
- Department of Pharmacognosy, Phytochemistry and Phytotherapy, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 020956 Bucharest, Romania
| | - Maria Coanda
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 020956 Bucharest, Romania
| | - Marcela Popa
- Research Institute of the University of Bucharest-ICUB, University of Bucharest, 50567 Bucharest, Romania
| | - Luminita Gabriela Marutescu
- Research Institute of the University of Bucharest-ICUB, University of Bucharest, 50567 Bucharest, Romania
- Department of Botany & Microbiology, University of Bucharest, 050095 Bucharest, Romania
| | - Irina Zarafu
- Department of Organic Chemistry, Biochemistry and Catalysis, Faculty of Chemistry, University of Bucharest, 050663 Bucharest, Romania
| | - Petre Ionita
- Department of Organic Chemistry, Biochemistry and Catalysis, Faculty of Chemistry, University of Bucharest, 050663 Bucharest, Romania
| | - Cristina Elena Dinu Pirvu
- Department of Physical and Colloidal Chemistry, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 020956 Bucharest, Romania
| | - Coralia Bleotu
- Research Institute of the University of Bucharest-ICUB, University of Bucharest, 50567 Bucharest, Romania
- Ştefan S. Nicolau Institute of Virology, 285 Mihai Bravu Avenue, 030304 Bucharest, Romania
| | - Mariana-Carmen Chifiriuc
- Department of Botany & Microbiology, University of Bucharest, 050095 Bucharest, Romania
- Romanian Academy, 050044 Bucharest, Romania
| | - Carmen Limban
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 020956 Bucharest, Romania
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Pirolla NFF, Batista VS, Dias Viegas FP, Gontijo VS, McCarthy CR, Viegas C, Nascimento-Júnior NM. Alzheimer's Disease: Related Targets, Synthesis of Available Drugs, Bioactive Compounds Under Development and Promising Results Obtained from Multi-target Approaches. Curr Drug Targets 2021; 22:505-538. [PMID: 32814524 DOI: 10.2174/1389450121999200819144544] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/27/2020] [Accepted: 05/14/2020] [Indexed: 11/22/2022]
Abstract
We describe herein the therapeutic targets involved in Alzheimer's disease as well as the available drugs and their synthetic routes. Bioactive compounds under development are also exploited to illustrate some recent research advances on the medicinal chemistry of Alzheimer's disease, including structure-activity relationships for some targets. The importance of multi-target approaches, including some examples from our research projects, guides new perspectives in search of more effective drug candidates. This review comprises the period between 2001 and early 2020.
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Affiliation(s)
- Natália F F Pirolla
- Laboratory of Medicinal Chemistry, Organic Synthesis, and Molecular Modelling (LaQMedSOMM), Institute of Chemistry, Department of Biochemistry and Organic Chemistry, Sao Paulo State University - UNESP, Rua Professor Francisco Degni, 55, Jardim Quitandinha, 14800-060, Araraquara-SP, Brazil
| | - Victor S Batista
- Laboratory of Medicinal Chemistry, Organic Synthesis, and Molecular Modelling (LaQMedSOMM), Institute of Chemistry, Department of Biochemistry and Organic Chemistry, Sao Paulo State University - UNESP, Rua Professor Francisco Degni, 55, Jardim Quitandinha, 14800-060, Araraquara-SP, Brazil
| | - Flávia Pereira Dias Viegas
- Laboratory of Research on Medicinal Chemistry (PeQuiM), Institute of Chemistry, Federal University of Alfenas, Alfenas-MG, 37133-840, Brazil
| | - Vanessa Silva Gontijo
- Laboratory of Research on Medicinal Chemistry (PeQuiM), Institute of Chemistry, Federal University of Alfenas, Alfenas-MG, 37133-840, Brazil
| | - Caitlin R McCarthy
- Laboratory of Medicinal Chemistry, Organic Synthesis, and Molecular Modelling (LaQMedSOMM), Institute of Chemistry, Department of Biochemistry and Organic Chemistry, Sao Paulo State University - UNESP, Rua Professor Francisco Degni, 55, Jardim Quitandinha, 14800-060, Araraquara-SP, Brazil
| | - Claudio Viegas
- Laboratory of Research on Medicinal Chemistry (PeQuiM), Institute of Chemistry, Federal University of Alfenas, Alfenas-MG, 37133-840, Brazil
| | - Nailton M Nascimento-Júnior
- Laboratory of Medicinal Chemistry, Organic Synthesis, and Molecular Modelling (LaQMedSOMM), Institute of Chemistry, Department of Biochemistry and Organic Chemistry, Sao Paulo State University - UNESP, Rua Professor Francisco Degni, 55, Jardim Quitandinha, 14800-060, Araraquara-SP, Brazil
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Vignaux PA, Minerali E, Lane TR, Foil DH, Madrid PB, Puhl AC, Ekins S. The Antiviral Drug Tilorone Is a Potent and Selective Inhibitor of Acetylcholinesterase. Chem Res Toxicol 2021; 34:1296-1307. [PMID: 33400519 DOI: 10.1021/acs.chemrestox.0c00466] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Acetylcholinesterase (AChE) is an important drug target in neurological disorders like Alzheimer's disease, Lewy body dementia, and Parkinson's disease dementia as well as for other conditions like myasthenia gravis and anticholinergic poisoning. In this study, we have used a combination of high-throughput screening, machine learning, and docking to identify new inhibitors of this enzyme. Bayesian machine learning models were generated with literature data from ChEMBL for eel and human AChE inhibitors as well as butyrylcholinesterase inhibitors (BuChE) and compared with other machine learning methods. High-throughput screens for the eel AChE inhibitor model identified several molecules including tilorone, an antiviral drug that is well-established outside of the United States, as a newly identified nanomolar AChE inhibitor. We have described how tilorone inhibits both eel and human AChE with IC50's of 14.4 nM and 64.4 nM, respectively, but does not inhibit the closely related BuChE IC50 > 50 μM. We have docked tilorone into the human AChE crystal structure and shown that this selectivity is likely due to the reliance on a specific interaction with a hydrophobic residue in the peripheral anionic site of AChE that is absent in BuChE. We also conducted a pharmacological safety profile (SafetyScreen44) and kinase selectivity screen (SelectScreen) that showed tilorone (1 μM) only inhibited AChE out of 44 toxicology target proteins evaluated and did not appreciably inhibit any of the 485 kinases tested. This study suggests there may be a potential role for repurposing tilorone or its derivatives in conditions that benefit from AChE inhibition.
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Affiliation(s)
- Patricia A Vignaux
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Eni Minerali
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Thomas R Lane
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Daniel H Foil
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Peter B Madrid
- SRI International, 333 Ravenswood Avenue, Menlo Park, California 94025, United States
| | - Ana C Puhl
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Sean Ekins
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
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6
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Donat CK, Hansen HH, Hansen HD, Mease RC, Horti AG, Pomper MG, L’Estrade ET, Herth MM, Peters D, Knudsen GM, Mikkelsen JD. In Vitro and In Vivo Characterization of Dibenzothiophene Derivatives [ 125I]Iodo-ASEM and [ 18F]ASEM as Radiotracers of Homo- and Heteromeric α7 Nicotinic Acetylcholine Receptors. Molecules 2020; 25:molecules25061425. [PMID: 32245032 PMCID: PMC7144377 DOI: 10.3390/molecules25061425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/25/2020] [Accepted: 02/27/2020] [Indexed: 12/18/2022] Open
Abstract
The α7 nicotinic acetylcholine receptor (α7 nAChR) is involved in several cognitive and physiologic processes; its expression levels and patterns change in neurologic and psychiatric diseases, such as schizophrenia and Alzheimer’s disease, which makes it a relevant drug target. Development of selective radioligands is important for defining binding properties and occupancy of novel molecules targeting the receptor. We tested the in vitro binding properties of [125I]Iodo-ASEM [(3-(1,4-diazabycyclo[3.2.2]nonan-4-yl)-6-(125I-iododibenzo[b,d]thiopentene 5,5-dioxide)] in the mouse, rat and pig brain using autoradiography. The in vivo binding properties of [18F]ASEM were investigated using positron emission tomography (PET) in the pig brain. [125I]Iodo-ASEM showed specific and displaceable high affinity (~1 nM) binding in mouse, rat, and pig brain. Binding pattern overlapped with [125I]α-bungarotoxin, specific binding was absent in α7 nAChR gene-deficient mice and binding was blocked by a range of α7 nAChR orthosteric modulators in an affinity-dependent order in the pig brain. Interestingly, relative to the wild-type, binding in β2 nAChR gene-deficient mice was lower for [125I]Iodo-ASEM (58% ± 2.7%) than [125I]α-bungarotoxin (23% ± 0.2%), potentially indicating different binding properties to heteromeric α7β2 nAChR. [18F]ASEM PET in the pig showed high brain uptake and reversible tracer kinetics with a similar spatial distribution as previously reported for α7 nAChR. Blocking with SSR-180,711 resulted in a significant decrease in [18F]ASEM binding. Our findings indicate that [125I]Iodo-ASEM allows sensitive and selective imaging of α7 nAChR in vitro, with better signal-to-noise ratio than previous tracers. Preliminary data of [18F]ASEM in the pig brain demonstrated principal suitable kinetic properties for in vivo quantification of α7 nAChR, comparable to previously published data.
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Affiliation(s)
- Cornelius K. Donat
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; (H.H.H.); (H.D.H.); (E.T.L.); (G.M.K.)
- Department of Brain Sciences, Imperial College London, London W12 0 LS, UK
- Correspondence: (C.K.D.); (J.D.M.); Tel.: +45-40205378 (J.D.M)
| | - Henrik H. Hansen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; (H.H.H.); (H.D.H.); (E.T.L.); (G.M.K.)
| | - Hanne D. Hansen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; (H.H.H.); (H.D.H.); (E.T.L.); (G.M.K.)
| | - Ronnie C. Mease
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (R.C.M.); (A.G.H.); (M.G.P.)
| | - Andrew G. Horti
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (R.C.M.); (A.G.H.); (M.G.P.)
| | - Martin G. Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (R.C.M.); (A.G.H.); (M.G.P.)
| | - Elina T. L’Estrade
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; (H.H.H.); (H.D.H.); (E.T.L.); (G.M.K.)
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 162, 2100 Copenhagen, Denmark;
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Matthias M. Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 162, 2100 Copenhagen, Denmark;
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | | | - Gitte M. Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; (H.H.H.); (H.D.H.); (E.T.L.); (G.M.K.)
| | - Jens D. Mikkelsen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; (H.H.H.); (H.D.H.); (E.T.L.); (G.M.K.)
- Correspondence: (C.K.D.); (J.D.M.); Tel.: +45-40205378 (J.D.M)
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Design, synthesis and biological evaluation of 1,4-Diazobicylco[3.2.2]nonane derivatives as α7-Nicotinic acetylcholine receptor PET/CT imaging agents and agonists for Alzheimer's disease. Eur J Med Chem 2018; 159:255-266. [PMID: 30296684 DOI: 10.1016/j.ejmech.2018.09.064] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 09/20/2018] [Accepted: 09/25/2018] [Indexed: 11/20/2022]
Abstract
α7-Nicotinic acetylcholine receptor (α7-nAChR) agonists are promising therapeutic drug candidates for treating the cognitive impairment associated with Alzheimer's disease (AD). Thus, a novel class of derivatives of 1,4-diazobicylco[3.2.2]nonane has been synthesized and evaluated as α7-nAChR ligands. Five of them displayed high binding affinity (Ki = 0.001-25 nM). In particular, the Ki of 14 was 0.0069 nM, which is superior to that of the most potent ligand that was previously reported by an order of magnitude. Four of them had high selectivity for α7-nAChRs over α4β2-nAChRs and no significant hERG (human ether-a-go-go-related gene) inhibition. Their agonist activity was also discussed preliminarily. One of the compounds, 15 (Ki = 2.98 ± 1.41 nM), was further radiolabeled with 18F to afford [18F]15 for PET imaging, which exhibited high initial brain uptake (11.60 ± 0.14%ID/g at 15 min post injection), brain/blood value (9.57 at 30 min post injection), specific labeling of α7-nAChRs and fast clearance from the brain. Blocking studies demonstrated that [18F]15 was α7-nAChR selective. In addition, micro-PET/CT imaging in normal rats further indicated that [18F]15 had obvious accumulation in the brain. Therefore, [18F]15 was proved to be a potential PET radiotracer for α7-nAChR imaging.
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Laha JK, Sharma S. Palladium-Catalyzed Intramolecular Oxidative Arylations for the Synthesis of Fused Biaryl Sulfones. ACS OMEGA 2018; 3:4860-4870. [PMID: 31458702 PMCID: PMC6641745 DOI: 10.1021/acsomega.8b00628] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/23/2018] [Indexed: 05/06/2023]
Abstract
This study unveils palladium-catalyzed intramolecular oxidative cyclizations in biaryl and heterobiaryl sulfones providing direct access to fused biaryl sulfones (dibenzothiophene-5,5-dioxides). Variously substituted dibenzothiophene-5,5-dioxides could be readily prepared in good to excellent yields under optimized conditions. In addition, bromination afforded dibromo derivative of dibenzothiophene-5,5-dioxides, providing platform for late-stage diversification. The translational applications of this current protocol have successfully been demonstrated in the synthesis of 2,8-diamino derivative of dibenzothiophene-5,5-dioxides, a α7-nicotinic acetylcholine receptor agonist analogue, and novel single fluorene-tethered dibenzothiophene-5,5-dioxide, an organic emitter.
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9
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Teodoro R, Scheunemann M, Wenzel B, Peters D, Deuther-Conrad W, Brust P. Synthesis and radiofluorination of novel fluoren-9-one based derivatives for the imaging of α7 nicotinic acetylcholine receptor with PET. Bioorg Med Chem Lett 2018; 28:1471-1475. [PMID: 29628323 DOI: 10.1016/j.bmcl.2018.03.081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 03/29/2018] [Indexed: 12/15/2022]
Abstract
By structure-activity relationship studies on the tilorone scaffold, the 'one armed' substituted dibenzothiophenes and the fluoren-9-ones were identified as the most potential α7 nAChR ligands. While the suitability of dibenzothiophene derivatives as PET tracers is recognized, the potential of fluoren-9-ones is insufficiently investigated. We herein report on a series of fluoren-9-one based derivatives targeting α7 nAChR with compounds 8a and 8c possessing the highest affinity and selectivity. Accordingly, with [18F]8a and [18F]8c we designed and initially evaluated the first fluoren-9-one derived α7 nAChR selective PET ligands. A future application of these radioligands is facilitated by the herein presented successful implementation of fully automated radiosynthesis.
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Affiliation(s)
- Rodrigo Teodoro
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Matthias Scheunemann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany
| | - Barbara Wenzel
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany
| | - Dan Peters
- DanPET AB, Rosenstigen 7, Malmö SE-21619, Sweden
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany
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Palladium supported SBA-functionalizd 1,2-dicarboxylic acid: The first Pd-based heterogeneous synthesis of fluorenones. MOLECULAR CATALYSIS 2018. [DOI: 10.1016/j.mcat.2017.12.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Efficacy of Tilorone Dihydrochloride against Ebola Virus Infection. Antimicrob Agents Chemother 2018; 62:AAC.01711-17. [PMID: 29133569 DOI: 10.1128/aac.01711-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/24/2017] [Indexed: 11/20/2022] Open
Abstract
Tilorone dihydrochloride (tilorone) is a small-molecule, orally bioavailable drug that is used clinically as an antiviral outside the United States. A machine-learning model trained on anti-Ebola virus (EBOV) screening data previously identified tilorone as a potent in vitro EBOV inhibitor, making it a candidate for the treatment of Ebola virus disease (EVD). In the present study, a series of in vitro ADMET (absorption, distribution, metabolism, excretion, toxicity) assays demonstrated the drug has excellent solubility, high Caco-2 permeability, was not a P-glycoprotein substrate, and had no inhibitory activity against five human CYP450 enzymes (3A4, 2D6, 2C19, 2C9, and 1A2). Tilorone was shown to have 52% human plasma protein binding with excellent plasma stability and a mouse liver microsome half-life of 48 min. Dose range-finding studies in mice demonstrated a maximum tolerated single dose of 100 mg/kg of body weight. A pharmacokinetics study in mice at 2- and 10-mg/kg dose levels showed that the drug is rapidly absorbed, has dose-dependent increases in maximum concentration of unbound drug in plasma and areas under the concentration-time curve, and has a half-life of approximately 18 h in both males and females, although the exposure was ∼2.5-fold higher in male mice. Tilorone doses of 25 and 50 mg/kg proved efficacious in protecting 90% of mice from a lethal challenge with mouse-adapted with once-daily intraperitoneal (i.p.) dosing for 8 days. A subsequent study showed that 30 mg/kg/day of tilorone given i.p. starting 2 or 24 h postchallenge and continuing through day 7 postinfection was fully protective, indicating promising activity for the treatment of EVD.
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Shaya J, Fontaine-Vive F, Michel BY, Burger A. Rational Design of Push-Pull Fluorene Dyes: Synthesis and Structure-Photophysics Relationship. Chemistry 2016; 22:10627-37. [PMID: 27304218 DOI: 10.1002/chem.201600581] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Indexed: 12/22/2022]
Abstract
Our work surveyed experimental and theoretical investigations to construct highly emissive D-π-A (D=donor, A=acceptor) fluorenes. The synthetic routes were optimised to be concise and gram-scalable. The molecular design was first rationalised by varying the electron-withdrawing group from an aldehyde, ketotriazole or succinyl to methylenemalonitrile or benzothiadiazole. The electron-donating group was next varied from aliphatic or aromatic amines to saturated cyclic amines ranging from aziridine to azepane. Spectroscopic studies correlated with TD-DFT calculations provided the optimised structures. The selected push-pull dyes exhibited visible absorptions, significant brightness, important solvatofluorochromism, mega-Stokes shifts (>250 nm) and dramatic shifts in emission to the near-infrared. The current library includes the comprehensive characterization of 16 prospective dyes for fluorescence applications. Among them, several fluorene derivatives bearing different conjugation anchors were tested for coupling and demonstrated to preserve the photophysical responses once further bound.
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Affiliation(s)
- Janah Shaya
- Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France
| | - Fabien Fontaine-Vive
- Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France
| | - Benoît Y Michel
- Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France
| | - Alain Burger
- Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, Parc Valrose, 06108, Nice Cedex 2, France.
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13
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Ekins S, Freundlich JS, Clark AM, Anantpadma M, Davey RA, Madrid P. Machine learning models identify molecules active against the Ebola virus in vitro. F1000Res 2016; 4:1091. [PMID: 26834994 DOI: 10.12688/f1000research.7217.2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/23/2015] [Indexed: 12/15/2022] Open
Abstract
The search for small molecule inhibitors of Ebola virus (EBOV) has led to several high throughput screens over the past 3 years. These have identified a range of FDA-approved active pharmaceutical ingredients (APIs) with anti-EBOV activity in vitro and several of which are also active in a mouse infection model. There are millions of additional commercially-available molecules that could be screened for potential activities as anti-EBOV compounds. One way to prioritize compounds for testing is to generate computational models based on the high throughput screening data and then virtually screen compound libraries. In the current study, we have generated Bayesian machine learning models with viral pseudotype entry assay and the EBOV replication assay data. We have validated the models internally and externally. We have also used these models to computationally score the MicroSource library of drugs to select those likely to be potential inhibitors. Three of the highest scoring molecules that were not in the model training sets, quinacrine, pyronaridine and tilorone, were tested in vitro and had EC50 values of 350, 420 and 230 nM, respectively. Pyronaridine is a component of a combination therapy for malaria that was recently approved by the European Medicines Agency, which may make it more readily accessible for clinical testing. Like other known antimalarial drugs active against EBOV, it shares the 4-aminoquinoline scaffold. Tilorone, is an investigational antiviral agent that has shown a broad array of biological activities including cell growth inhibition in cancer cells, antifibrotic properties, α7 nicotinic receptor agonist activity, radioprotective activity and activation of hypoxia inducible factor-1. Quinacrine is an antimalarial but also has use as an anthelmintic. Our results suggest data sets with less than 1,000 molecules can produce validated machine learning models that can in turn be utilized to identify novel EBOV inhibitors in vitro.
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Affiliation(s)
- Sean Ekins
- Collaborations in Chemistry, Fuquay-Varina, NC, 27526, USA
- Collaborations Pharmaceuticals Inc, Fuquay-Varina, NC, 27526, USA
- Collaborative Drug Discovery, Burlingame, CA, 94010, USA
| | - Joel S Freundlich
- Departments of Pharmacology & Physiology and Medicine, Center for Emerging and Reemerging Pathogens, UMDNJ, New Jersey Medical School, Newark, NJ, 07103, USA
| | - Alex M Clark
- Molecular Materials Informatics, Inc., Montreal, 94025, Canada
| | - Manu Anantpadma
- Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
| | - Robert A Davey
- Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
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14
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Uspenska KR, Gergalova GL, Lykhmus OY, Skok MV. The effect of amixin and agmatine on cytochrome C release from isolated mitochondria. UKRAINIAN BIOCHEMICAL JOURNAL 2016; 88:5-10. [PMID: 29227073 DOI: 10.15407/ubj88.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial nicotinic acetylcholine receptors (nAChRs) control permeability transition pore formation
and cytochrome c release in the presence of apoptogenic factors. This study demonstrates that pharmacological
agents amixin and agmatine affect mitochondrial nAChR functioning: they slightly suppress
cytochrome c release from mouse brain and liver mitochondria stimulated with apoptogenic dose of Са2+ and
prevent the effect of α7 nAChR agonist PNU282987. We conclude that mitochondria may be one of therapeutic
targets of amixin and agmatine.
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15
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Ekins S, Freundlich JS, Clark AM, Anantpadma M, Davey RA, Madrid P. Machine learning models identify molecules active against the Ebola virus in vitro. F1000Res 2015; 4:1091. [PMID: 26834994 DOI: 10.12688/f1000research.7217.1] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/15/2015] [Indexed: 12/23/2022] Open
Abstract
The search for small molecule inhibitors of Ebola virus (EBOV) has led to several high throughput screens over the past 3 years. These have identified a range of FDA-approved active pharmaceutical ingredients (APIs) with anti-EBOV activity in vitro and several of which are also active in a mouse infection model. There are millions of additional commercially-available molecules that could be screened for potential activities as anti-EBOV compounds. One way to prioritize compounds for testing is to generate computational models based on the high throughput screening data and then virtually screen compound libraries. In the current study, we have generated Bayesian machine learning models with viral pseudotype entry assay and the EBOV replication assay data. We have validated the models internally and externally. We have also used these models to computationally score the MicroSource library of drugs to select those likely to be potential inhibitors. Three of the highest scoring molecules that were not in the model training sets, quinacrine, pyronaridine and tilorone, were tested in vitro and had EC 50 values of 350, 420 and 230 nM, respectively. Pyronaridine is a component of a combination therapy for malaria that was recently approved by the European Medicines Agency, which may make it more readily accessible for clinical testing. Like other known antimalarial drugs active against EBOV, it shares the 4-aminoquinoline scaffold. Tilorone, is an investigational antiviral agent that has shown a broad array of biological activities including cell growth inhibition in cancer cells, antifibrotic properties, α7 nicotinic receptor agonist activity, radioprotective activity and activation of hypoxia inducible factor-1. Quinacrine is an antimalarial but also has use as an anthelmintic. Our results suggest data sets with less than 1,000 molecules can produce validated machine learning models that can in turn be utilized to identify novel EBOV inhibitors in vitro.
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Affiliation(s)
- Sean Ekins
- Collaborations in Chemistry, Fuquay-Varina, NC, 27526, USA.,Collaborations Pharmaceuticals Inc, Fuquay-Varina, NC, 27526, USA.,Collaborative Drug Discovery, Burlingame, CA, 94010, USA
| | - Joel S Freundlich
- Departments of Pharmacology & Physiology and Medicine, Center for Emerging and Reemerging Pathogens, UMDNJ, New Jersey Medical School, Newark, NJ, 07103, USA
| | - Alex M Clark
- Molecular Materials Informatics, Inc., Montreal, 94025, Canada
| | - Manu Anantpadma
- Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
| | - Robert A Davey
- Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
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16
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Ekins S, Freundlich JS, Clark AM, Anantpadma M, Davey RA, Madrid P. Machine learning models identify molecules active against the Ebola virus in vitro. F1000Res 2015; 4:1091. [PMID: 26834994 PMCID: PMC4706063 DOI: 10.12688/f1000research.7217.3] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 12/21/2022] Open
Abstract
The search for small molecule inhibitors of Ebola virus (EBOV) has led to several high throughput screens over the past 3 years. These have identified a range of FDA-approved active pharmaceutical ingredients (APIs) with anti-EBOV activity
in vitro and several of which are also active in a mouse infection model. There are millions of additional commercially-available molecules that could be screened for potential activities as anti-EBOV compounds. One way to prioritize compounds for testing is to generate computational models based on the high throughput screening data and then virtually screen compound libraries. In the current study, we have generated Bayesian machine learning models with viral pseudotype entry assay and the EBOV replication assay data. We have validated the models internally and externally. We have also used these models to computationally score the MicroSource library of drugs to select those likely to be potential inhibitors. Three of the highest scoring molecules that were not in the model training sets, quinacrine, pyronaridine and tilorone, were tested
in vitro and had EC
50 values of 350, 420 and 230 nM, respectively. Pyronaridine is a component of a combination therapy for malaria that was recently approved by the European Medicines Agency, which may make it more readily accessible for clinical testing. Like other known antimalarial drugs active against EBOV, it shares the 4-aminoquinoline scaffold. Tilorone, is an investigational antiviral agent that has shown a broad array of biological activities including cell growth inhibition in cancer cells, antifibrotic properties, α7 nicotinic receptor agonist activity, radioprotective activity and activation of hypoxia inducible factor-1. Quinacrine is an antimalarial but also has use as an anthelmintic. Our results suggest data sets with less than 1,000 molecules can produce validated machine learning models that can in turn be utilized to identify novel EBOV inhibitors
in vitro.
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Affiliation(s)
- Sean Ekins
- Collaborations in Chemistry, Fuquay-Varina, NC, 27526, USA.,Collaborations Pharmaceuticals Inc, Fuquay-Varina, NC, 27526, USA.,Collaborative Drug Discovery, Burlingame, CA, 94010, USA
| | - Joel S Freundlich
- Departments of Pharmacology & Physiology and Medicine, Center for Emerging and Reemerging Pathogens, UMDNJ, New Jersey Medical School, Newark, NJ, 07103, USA
| | - Alex M Clark
- Molecular Materials Informatics, Inc., Montreal, 94025, Canada
| | - Manu Anantpadma
- Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
| | - Robert A Davey
- Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
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17
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Teodoro R, Scheunemann M, Deuther-Conrad W, Wenzel B, Fasoli FM, Gotti C, Kranz M, Donat CK, Patt M, Hillmer A, Zheng MQ, Peters D, Steinbach J, Sabri O, Huang Y, Brust P. A Promising PET Tracer for Imaging of α₇ Nicotinic Acetylcholine Receptors in the Brain: Design, Synthesis, and in Vivo Evaluation of a Dibenzothiophene-Based Radioligand. Molecules 2015; 20:18387-421. [PMID: 26473809 PMCID: PMC6332508 DOI: 10.3390/molecules201018387] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/25/2015] [Accepted: 09/28/2015] [Indexed: 01/22/2023] Open
Abstract
Changes in the expression of α7 nicotinic acetylcholine receptors (α7 nAChRs) in the human brain are widely assumed to be associated with neurological and neurooncological processes. Investigation of these receptors invivo depends on the availability of imaging agents such as radioactively labelled ligands applicable in positron emission tomography (PET). We report on a series of new ligands for α7 nAChRs designed by the combination of dibenzothiophene dioxide as a novel hydrogen bond acceptor functionality with diazabicyclononane as an established cationic center. To assess the structure-activity relationship (SAR) of this new basic structure, we further modified the cationic center systematically by introduction of three different piperazine-based scaffolds. Based on invitro binding affinity and selectivity, assessed by radioligand displacement studies at different rat and human nAChR subtypes and at the structurally related human 5-HT3 receptor, we selected the compound 7-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-2-fluorodibenzo-[b,d]thiophene 5,5-dioxide (10a) for radiolabeling and further evaluation invivo. Radiosynthesis of [18F]10a was optimized and transferred to an automated module. Dynamic PET imaging studies with [18F]10a in piglets and a monkey demonstrated high uptake of radioactivity in the brain, followed by washout and target-region specific accumulation under baseline conditions. Kinetic analysis of [18F]10a in pig was performed using a two-tissue compartment model with arterial-derived input function. Our initial evaluation revealed that the dibenzothiophene-based PET radioligand [18F]10a ([18F]DBT-10) has high potential to provide clinically relevant information about the expression and availability of α7 nAChR in the brain.
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Affiliation(s)
- Rodrigo Teodoro
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Matthias Scheunemann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Barbara Wenzel
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Francesca Maria Fasoli
- Consiglio Nazionale delle Ricerche, Institute of Neuroscience, Biometra-Institute University of Milan, Via Luigi Vanvitelli 32, Milano 20129, Italy.
| | - Cecilia Gotti
- Consiglio Nazionale delle Ricerche, Institute of Neuroscience, Biometra-Institute University of Milan, Via Luigi Vanvitelli 32, Milano 20129, Italy.
| | - Mathias Kranz
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Cornelius K Donat
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Marianne Patt
- Department of Nuclear Medicine, University Hospital Leipzig, Liebigstraße 18, Leipzig 04103, Germany.
| | - Ansel Hillmer
- PET Center, Yale University, P.O. Box 208048, 801 Howard Avenue, New Haven, CT 06520-8048, USA.
| | - Ming-Qiang Zheng
- PET Center, Yale University, P.O. Box 208048, 801 Howard Avenue, New Haven, CT 06520-8048, USA.
| | - Dan Peters
- Dan PET AB, Rosenstigen 7, Malmö SE-21619, Sweden.
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
| | - Osama Sabri
- Department of Nuclear Medicine, University Hospital Leipzig, Liebigstraße 18, Leipzig 04103, Germany.
| | - Yiyun Huang
- PET Center, Yale University, P.O. Box 208048, 801 Howard Avenue, New Haven, CT 06520-8048, USA.
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, Leipzig 04318, Germany.
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18
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Bertrand D, Lee CHL, Flood D, Marger F, Donnelly-Roberts D. Therapeutic Potential of α7 Nicotinic Acetylcholine Receptors. Pharmacol Rev 2015; 67:1025-73. [DOI: 10.1124/pr.113.008581] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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19
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Horti AG. Development of [(18)F]ASEM, a specific radiotracer for quantification of the α7-nAChR with positron-emission tomography. Biochem Pharmacol 2015; 97:566-575. [PMID: 26232729 DOI: 10.1016/j.bcp.2015.07.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/24/2015] [Indexed: 12/20/2022]
Abstract
The alpha-7 subtype of the nicotinic acetylcholine receptor (α7-nAChR) is fundamental to physiology; it mediates various brain functions and represents an important target for drug discovery. Exploration of the brain nicotinic acetylcholine receptors (nAChRs) using positron-emission tomography (PET) will make it possible to better understand the important role of this receptor and to study its involvement in schizophrenia, bipolar disorder, Alzheimer's and Parkinson's diseases, drug dependence, inflammation and many other disorders and simplify the development of nicotinic drugs for treatment of these disorders. Until recently, PET imaging of α7-nAChRs has been impeded by the absence of good radiotracers. This review describes various endeavors to develop α7-nAChR PET tracers by several research groups including the author's group. Most initial PET tracers for imaging α7-nAChRs did not exhibit suitable imaging properties due to their low specific binding. Newly discovered [(18)F]ASEM is the first highly specific α7-nAChR radioligand and in 2014 it was translated to human PET imaging.
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Affiliation(s)
- Andrew G Horti
- Department of Radiology, The Johns Hopkins School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287-0816, USA.
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20
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Barrett MJ, Davies PW, Grainger RS. Regioselective functionalisation of dibenzothiophenes through gold-catalysed intermolecular alkyne oxyarylation. Org Biomol Chem 2015; 13:8676-86. [PMID: 26177794 DOI: 10.1039/c5ob01241d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A protocol has been developed for direct Csp(3)-Csp(2) bond formation at the 4- and 6-positions of dibenzothiophenes using a gold(I) catalyst with terminal alkynes and dibenzothiophene-S-oxides. The sulfoxide acts as a traceless directing group to avoid the need to prefunctionalise at carbon. The iterative use of this protocol is possible and has been employed in the preparation of novel macrocyclic structures. In addition, a cascade process shows how oxyarylations can be combined with other processes resulting in complex, highly efficient transformations.
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Affiliation(s)
- Matthew J Barrett
- School of Chemistry, University of Birmingham, Haworth Building, Edgbaston, Birmingham, B15 2TT, UK.
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21
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Shibata T, Tahara YK, Matsubara R. [2+2+2] Cycloaddition of Sulfanylbenzene-Tethered Diynes with Alkynes for the Synthesis of Multi-Substituted Dibenzothiophene Derivatives. HETEROCYCLES 2015. [DOI: 10.3987/com-14-s(k)78] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Mangione MI, Spanevello RA. Synthesis of nitrogenated scaffolds derived from fluorene by a modified Ullmann type reaction. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2014.11.133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Teodoro R, Wenzel B, Oh-Nishi A, Fischer S, Peters D, Suhara T, Deuther-Conrad W, Brust P. A high-yield automated radiosynthesis of the alpha-7 nicotinic receptor radioligand [ 18F]NS10743. Appl Radiat Isot 2014; 95:76-84. [PMID: 25464181 DOI: 10.1016/j.apradiso.2014.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/16/2014] [Accepted: 09/29/2014] [Indexed: 01/30/2023]
Abstract
[18F]NS10743, a promising and highly competitive α7 nAChR radioligand has been synthesized so far by microwave irradiation using a manual single-mode device followed by a palladium-catalyzed reduction of remaining nitro-precursor for HPLC separation purposes. For further preclinical and clinical use, regulated production of [18F]NS10743 by fully automated radiosynthesis is a crucial requirement. Therefore, we chose a commercial synthesis module and developed the automated radiosynthesis of [18F]NS10743. Besides evaluation of several radiosynthesis procedures, we performed an extensive HPLC study for quantitative separation of [18F]NS10743 from the corresponding nitro precursor. After implementation of the optimized procedure on a TRACERlabTM FX F-N synthesis module, [18F]NS10743 was obtained in high radiochemical purity (≥99%) with an overall radiochemical yield of 32.2±7% (n=3). The specific activities at the end of the synthesis were 571±17GBq/µmol (n=3).
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Affiliation(s)
- Rodrigo Teodoro
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Germany.
| | - Barbara Wenzel
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Germany
| | - Arata Oh-Nishi
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan
| | - Steffen Fischer
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Germany
| | | | - Tetsuya Suhara
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan
| | - Winnie Deuther-Conrad
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Research Site Leipzig, Germany
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Wissing MD, Dadon T, Kim E, Piontek KB, Shim JS, Kaelber NS, Liu JO, Kachhap SK, Nelkin BD. Small-molecule screening of PC3 prostate cancer cells identifies tilorone dihydrochloride to selectively inhibit cell growth based on cyclin-dependent kinase 5 expression. Oncol Rep 2014; 32:419-24. [PMID: 24841903 PMCID: PMC4067428 DOI: 10.3892/or.2014.3174] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 04/22/2014] [Indexed: 12/13/2022] Open
Abstract
Cyclin-dependent kinase 5 (CDK5) is a potential target for prostate cancer treatment, the enzyme being essential for prostate tumor growth and formation of metastases. In the present study, we identified agents that target prostate cancer cells based on CDK5 expression. CDK5 activity was suppressed by transfection of PC3 prostate cancer cells with a dominant-negative construct (PC3 CDK5dn). PC3 CDK5dn and PC3 control cells were screened for compounds that selectively target cells based on CDK5 expression, utilizing the Johns Hopkins Drug Library. MTS proliferation, clonogenic and 3D growth assays were performed to validate the selected hits. Screening of 3,360 compounds identified rutilantin, ethacridine lactate and cetalkonium chloride as compounds that selectively target PC3 control cells and a tilorone analog as a selective inhibitor of PC3 CDK5dn cells. A PubMed literature study indicated that tilorone may have clinical use in patients. Validation experiments confirmed that tilorone treatment resulted in decreased PC3 cell growth and invasion; PC3 cells with inactive CDK5 were inhibited more effectively. Future studies are needed to unravel the mechanism of action of tilorone in CDK5 deficient prostate cancer cells and to test combination therapies with tilorone and a CDK5 inhibitor for its potential use in clinical practice.
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Affiliation(s)
- Michel D Wissing
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Tikva Dadon
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Eunice Kim
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Klaus B Piontek
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Joong S Shim
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nadine S Kaelber
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jun O Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sushant K Kachhap
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Barry D Nelkin
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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25
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Horti AG, Gao Y, Kuwabara H, Wang Y, Abazyan S, Yasuda RP, Tran T, Xiao Y, Sahibzada N, Holt DP, Kellar KJ, Pletnikov MV, Pomper MG, Wong DF, Dannals RF. 18F-ASEM, a radiolabeled antagonist for imaging the α7-nicotinic acetylcholine receptor with PET. J Nucl Med 2014; 55:672-7. [PMID: 24556591 DOI: 10.2967/jnumed.113.132068] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED The α7-nicotinic cholinergic receptor (α7-nAChR) is a key mediator of brain communication and has been implicated in a wide variety of central nervous system disorders. None of the currently available PET radioligands for α7-nAChR are suitable for quantitative PET imaging, mostly because of insufficient specific binding. The goal of this study was to evaluate the potential of (18)F-ASEM ((18)F-JHU82132) as an α7-nAChR radioligand for PET. METHODS The inhibition binding assay and receptor functional properties of ASEM were assessed in vitro. The brain regional distribution of (18)F-ASEM in baseline and blockade were evaluated in DISC1 mice (dissection) and baboons (PET). RESULTS ASEM is an antagonist for the α7-nAChR with high binding affinity (Ki = 0.3 nM). (18)F-ASEM readily entered the baboon brain and specifically labeled α7-nAChR. The in vivo specific binding of (18)F-ASEM in the brain regions enriched with α7-nAChRs was 80%-90%. SSR180711, an α7-nAChR-selective partial agonist, blocked (18)F-ASEM binding in the baboon brain in a dose-dependent manner, suggesting that the binding of (18)F-ASEM was mediated by α7-nAChRs and the radioligand was suitable for drug evaluation studies. In the baboon baseline studies, the brain regional volume of distribution (VT) values for (18)F-ASEM were 23 (thalamus), 22 (insula), 18 (hippocampus), and 14 (cerebellum), whereas in the binding selectivity (blockade) scan, all regional VT values were reduced to less than 4. The range of regional binding potential values in the baboon brain was from 3.9 to 6.6. In vivo cerebral binding of (18)F-ASEM and α7-nAChR expression in mutant DISC1 mice, a rodent model of schizophrenia, was significantly lower than in control animals, which is in agreement with previous postmortem human data. CONCLUSION (18)F-ASEM holds promise as a radiotracer with suitable imaging properties for quantification of α7-nAChR in the human brain.
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Affiliation(s)
- Andrew G Horti
- Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland
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Gao Y, Kellar KJ, Yasuda RP, Tran T, Xiao Y, Dannals RF, Horti AG. Derivatives of dibenzothiophene for positron emission tomography imaging of α7-nicotinic acetylcholine receptors. J Med Chem 2013; 56:7574-89. [PMID: 24050653 DOI: 10.1021/jm401184f] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A new series of derivatives of 3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)dibenzo[b,d]thiophene 5,5-dioxide with high binding affinities and selectivity for α7-nicotinic acetylcholine receptors (α7-nAChRs) (Ki = 0.4-20 nM) has been synthesized for positron emission tomography (PET) imaging of α7-nAChRs. Two radiolabeled members of the series [(18)F]7a (Ki = 0.4 nM) and [(18)F]7c (Ki = 1.3 nM) were synthesized. [(18)F]7a and [(18)F]7c readily entered the mouse brain and specifically labeled α7-nAChRs. The α7-nAChR selective ligand 1 (SSR180711) blocked the binding of [(18)F]7a in the mouse brain in a dose-dependent manner. The mouse blocking studies with non-α7-nAChR central nervous system drugs demonstrated that [(18)F]7a is highly α7-nAChR selective. In agreement with its binding affinity the binding potential of [(18)F]7a (BPND = 5.3-8.0) in control mice is superior to previous α7-nAChR PET radioligands. Thus, [(18)F]7a displays excellent imaging properties in mice and has been chosen for further evaluation as a potential PET radioligand for imaging of α7-nAChR in non-human primates.
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Affiliation(s)
- Yongjun Gao
- Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Nuclear Medicine, The Johns Hopkins University School of Medicine , 600 North Wolfe Street, Baltimore, Maryland 21287-0816, United States
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Lee CC, Chang DM, Huang KF, Chen CL, Chen TC, Lo Y, Guh JH, Huang HS. Design, synthesis and antiproliferative evaluation of fluorenone analogs with DNA topoisomerase I inhibitory properties. Bioorg Med Chem 2013; 21:7125-33. [PMID: 24094433 DOI: 10.1016/j.bmc.2013.09.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 11/29/2022]
Abstract
A series of 2,7-diamidofluorenones were designed, synthesized, and screened by SRB assay. Some synthesized compounds exhibited antitumor activities in submicromolar range. Ten compounds (3a, 3b, 3c, 3g, 3j, 3l, 4a, 4h, 4i, and 4j) were also selected by NCI screening system and 3c (GI50=1.66 μM) appeared to be the most active agent of this series. Furthermore, 3c attenuated topoisomerase I-mediated DNA relaxation at low micromolar concentrations. These results indicated that fluorenones have potential to be further developed into anticancer drugs.
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Affiliation(s)
- Chia-Chung Lee
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan; School of Pharmacy, National Defense Medical Center, Taipei 114, Taiwan
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Horti AG, Ravert HT, Gao Y, Holt DP, Bunnelle WH, Schrimpf MR, Li T, Ji J, Valentine H, Scheffel U, Kuwabara H, Wong DF, Dannals RF. Synthesis and evaluation of new radioligands [(11)C]A-833834 and [(11)C]A-752274 for positron-emission tomography of α7-nicotinic acetylcholine receptors. Nucl Med Biol 2013; 40:395-402. [PMID: 23294899 PMCID: PMC3596482 DOI: 10.1016/j.nucmedbio.2012.11.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/31/2012] [Accepted: 11/20/2012] [Indexed: 01/31/2023]
Abstract
INTRODUCTION α7-nicotinic acetylcholine receptor (α7-nAChR) is one of the major neuronal nAChR subtypes. α7-nAChR is involved in variety of neuronal processes and disorders including schizophrenia and Alzheimer's disease. A number of α7-nAChR PET radioligands have been developed, but a quality radiotracer remains to be discovered. METHODS High binding affinity α7-nAChR ligands A-833834 and A-752274 were radiolabeled with (11)C. Baseline and blockade biodistribution studies in the mouse brain of [(11)C]A-833834 (5-(6-(5-[(11)C]methylhexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl)pyridazin-3-yl)-1H-indole) and [(11)C]A-752274 (2-(6-[(11)C]methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)-7-(6-methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)-9H-fluoren-9-one) were performed. [(11)C]A-752274 was evaluated in a baseline baboon PET study. RESULTS [(11)C]A-833834 and [(11)C]A-752274 were synthesized by radiomethylation of corresponding des-methyl precursors. The radioligands were prepared with radiochemical yield of 12%-32%, high specific radioactivity (330-403GBq/μmol) and radiochemical purity>95%. Dissection studies with [(11)C]A-833834 demonstrated low specific α7-nAChR binding in the mouse brain. [(11)C]A-752274 specifically (~50%) labeled α7-nAChR in the mouse thalamus. However, [(11)CA-752274 exhibited low brain uptake in baboon (%SUV<100). CONCLUSION Two novel α7-nAChR ligands radioligands were synthesized and studied in animals. Specific binding of [(11)C]A-833834 in the mouse brain is low due to the insufficient binding affinity of the radioligand. The very high binding affinity [(11)C]A-752274 exhibited good specific binding in the α7-nAChR-rich mouse brain regions. The low uptake of [(11)C]A-752274 in the baboon brain is due to its high hydrophilicity, rapid metabolism or other properties. Future development of α7-nAChR PET radioligands will be based on compounds with high binding affinities and good blood-brain barrier permeability.
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Affiliation(s)
- Andrew G Horti
- Division of Nuclear Medicine, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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