1
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Pou S, Winter RW, Liebman KM, Dodean RA, Nilsen A, DeBarber A, Doggett JS, Riscoe MK. Synthesis of Deuterated Endochin-Like Quinolones. J Labelled Comp Radiopharm 2024. [PMID: 38661253 DOI: 10.1002/jlcr.4092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 03/05/2024] [Accepted: 03/13/2024] [Indexed: 04/26/2024]
Abstract
Malaria continues to be a serious and debilitating disease. The emergence and spread of high-level resistance to multiple antimalarial drugs by Plasmodium falciparum has brought about an urgent need for new treatments that will be active against multidrug resistant malaria infections. One such treatment, ELQ-331 (MMV-167), an alkoxy carbonate prodrug of 4(1H)-quinolone ELQ-300, is currently in preclinical development with the Medicines for Malaria Venture. Clinical development of ELQ-331 or similar compounds will require the availability of isotopically labeled analogs. Unfortunately, a suitable method for the deuteration of these important compounds was not found in the literature. Here, we describe a facile and scalable method for the deuteration of 4(1H)-quinolone ELQ-300, its alkoxycarbonate prodrug ELQ-331, and their respective N-oxides using deuterated acetic acid.
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Affiliation(s)
- Sovitj Pou
- Medical Research Service, VA Healthcare System, Portland, Oregon, USA
| | - Rolf W Winter
- Medical Research Service, VA Healthcare System, Portland, Oregon, USA
| | | | - Rosie A Dodean
- Medical Research Service, VA Healthcare System, Portland, Oregon, USA
| | - Aaron Nilsen
- Medical Research Service, VA Healthcare System, Portland, Oregon, USA
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, USA
| | - Andrea DeBarber
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, Oregon, USA
| | - J Stone Doggett
- Medical Research Service, VA Healthcare System, Portland, Oregon, USA
- Division of Infectious Diseases, School of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Michael K Riscoe
- Medical Research Service, VA Healthcare System, Portland, Oregon, USA
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon, USA
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2
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Vydyam P, Chand M, Pou S, Winter RW, Liebman KM, Nilsen A, Doggett JS, Riscoe MK, Ben Mamoun C. Effectiveness of Two New Endochin-like Quinolones, ELQ-596 and ELQ-650, in Experimental Mouse Models of Human Babesiosis. ACS Infect Dis 2024; 10:1405-1413. [PMID: 38563132 DOI: 10.1021/acsinfecdis.4c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Endochin-like quinolones (ELQs) define a class of small molecule antimicrobials that target the mitochondrial electron transport chain of various human parasites by inhibiting their cytochrome bc1 complexes. The compounds have shown potent activity against a wide range of protozoan parasites, including the intraerythrocytic parasites Plasmodium and Babesia, the agents of human malaria and babesiosis, respectively. First-generation ELQ compounds were previously found to reduce infection by Babesia microti and Babesia duncani in animal models of human babesiosis but achieved a radical cure only in combination with atovaquone and required further optimization to address pharmacological limitations. Here, we report the identification of two second-generation 3-biaryl ELQ compounds, ELQ-596 and ELQ-650, with potent antibabesial activity in vitro and favorable pharmacological properties. In particular, ELQ-598, a prodrug of ELQ-596, demonstrated high efficacy as an orally administered monotherapy at 10 mg/kg. The compound achieved radical cure in both the chronic model of B. microti-induced babesiosis in immunocompromised mice and the lethal infection model induced by B. duncani in immunocompetent mice. Given its high potency, favorable physicochemical properties, and low toxicity profile, ELQ-596 represents a promising drug for the treatment of human babesiosis.
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Affiliation(s)
| | | | - Sovitj Pou
- Experimental Chemotherapy Lab, VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Rolf W Winter
- Experimental Chemotherapy Lab, VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Katherine M Liebman
- Experimental Chemotherapy Lab, VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Aaron Nilsen
- Experimental Chemotherapy Lab, VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - J Stone Doggett
- Experimental Chemotherapy Lab, VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
- Department of Medicine, Division of Infectious Diseases, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Michael K Riscoe
- Experimental Chemotherapy Lab, VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
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3
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Bonhof-Jansen EDJ, van Ham A, Kroon GJ, Winter RW, Brink SM. Validity and reliability of a portable handheld dynamometer compared to a fixed isokinetic dynamometer to assess forearm torque strength. Hand Surg Rehabil 2022; 42:147-153. [PMID: 36567012 DOI: 10.1016/j.hansur.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/02/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
To evaluate the effect of treatment on forearm rotation, torque muscle strength can be assessed using an isokinetic device (IKD) or a wrist dynamometer (WD). The aims of this study were 1) to determine concurrent validity and intra- and inter-rater reliability using the WD, and to examine correlations between WD and IKD in different positions; and 2) subsequently, to establish the intermethod reproducibility between WD as a handheld (HHD) or fixed device. We conducted a cross-sectional study in which torque strength was measured in healthy participants by two observers using an IKD and a WD. Study endpoints were concurrent validity (Pearson's r), intra- and inter-rater reliability, intermethod reproducibility (intraclass correlation coefficient: ICC) and measurement error (limits of agreement: LoA). Concurrent validity ranged, in the 2 studies assessing it, from r 0.37 to 0.52 for pronation and from r 0.50 to 0.82 for supination, with wide 95% confidence intervals. ICC for intra-rater reliability for pronation ranged from 0.85 to 0.91 and for supination from 0.91 to 0.95. ICC for inter-rater reliability for pronation ranged from 0.84 to 0.96 and for supination from 0.92 to 0.96. Despite the excellent intra- and inter-rater reliability and intermethod reproducibility for the WD-HHD and fixed WD, validity was low when compared to IKD and wide LoA indicated a high measurement error of approximately 20%. These results suggest that the WD cannot replace the IKD isometric mode for pronation and supination. LEVEL OF EVIDENCE: 2.
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Affiliation(s)
| | - A van Ham
- Vogellanden Center of Rehabilitation Medicine, Zwolle, The Netherlands.
| | - G J Kroon
- Isala Hospital, Hand-Wrist Centre, Zwolle, The Netherlands.
| | - R W Winter
- Isala Hospital, Hand-Wrist Centre, Zwolle, The Netherlands; Vogellanden Center of Rehabilitation Medicine, Zwolle, The Netherlands.
| | - S M Brink
- Isala Hospital, Hand-Wrist Centre, Zwolle, The Netherlands; Vogellanden Center of Rehabilitation Medicine, Zwolle, The Netherlands.
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4
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Pal AC, Renard I, Singh P, Vydyam P, Chiu JE, Pou S, Winter RW, Dodean R, Frueh L, Nilsen AC, Riscoe MK, Doggett JS, Ben Mamoun C. Babesia duncani as a Model Organism to Study the Development, Virulence, and Drug Susceptibility of Intraerythrocytic Parasites In Vitro and In Vivo. J Infect Dis 2022; 226:1267-1275. [PMID: 35512141 DOI: 10.1093/infdis/jiac181] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/02/2022] [Indexed: 02/07/2023] Open
Abstract
Human babesiosis is a malaria-like illness caused by tick-borne intraerythrocytic Babesia parasites of the Apicomplexa phylum. Whereas several species of Babesia can cause severe disease in humans, the ability to propagate Babesia duncani both in vitro in human erythrocytes and in mice makes it a unique pathogen to study Babesia biology and pathogenesis. Here we report an optimized B. duncani in culture-in mouse (ICIM) model that combines continuous in vitro culture of the parasite with a precise model of lethal infection in mice. We demonstrate that B. duncani-infected erythrocytes as well as free merozoites can cause lethal infection in C3H/HeJ mice. Highly reproducible parasitemia and survival outcomes could be established using specific parasite loads in different mouse genetic backgrounds. Using the ICIM model, we discovered 2 new endochin-like quinolone prodrugs (ELQ-331 and ELQ-468) that alone or in combination with atovaquone are highly efficacious against B. duncani and Babesia microti.
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Affiliation(s)
- Anasuya C Pal
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Isaline Renard
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Pallavi Singh
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Pratap Vydyam
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Joy E Chiu
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Sovitj Pou
- Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - Rolf W Winter
- Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - Rozalia Dodean
- Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - Lisa Frueh
- Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - Aaron C Nilsen
- Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - Michael K Riscoe
- Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - J Stone Doggett
- Veterans Affairs Portland Health Care System, Portland, Oregon, USA
| | - Choukri Ben Mamoun
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
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5
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Pou S, Dodean RA, Frueh L, Liebman KM, Gallagher RT, Jin H, Jacobs RT, Nilsen A, Stuart DR, Doggett JS, Riscoe MK, Winter RW. A New Scalable Synthesis of ELQ-300, ELQ-316, and other Antiparasitic Quinolones. Org Process Res Dev 2021; 25:1841-1852. [PMID: 35110959 DOI: 10.1021/acs.oprd.1c00099] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Endochin-Like Quinolone (ELQ) compound class may yield effective, safe treatments for a range of important human and animal afflictions. However, to access the public health potential of this compound series, a synthetic route needed to be devised that lowers costs and is amenable to large scale production. In the new synthetic route described here, a substituted β-keto ester, formed by an Ullmann reaction and subsequent acylation, is reacted with an aniline via a Conrad-Limpach reaction to produce 3-substituted 4(1H)-quinolones such as ELQ-300 and ELQ-316. This synthetic route, the first described to be truly amenable to industrial scale production, is relatively short (5 reaction steps), does not require palladium, chromatographic separation or protecting group chemistry, and may be performed without high vacuum distillation.
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Affiliation(s)
- Sovitj Pou
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Rozalia A Dodean
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Lisa Frueh
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Katherine M Liebman
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Rory T Gallagher
- Department of Chemistry, Portland State University, 1719 SW 10 Avenue, Portland, Oregon 97201, United States
| | - Haihong Jin
- Medicinal Chemistry Core, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Robert T Jacobs
- Medicines for Malaria Venture, ICC, route de Pré-Bois 20, P.O. Box 1826, 1215 Geneva 15, Switzerland
| | - Aaron Nilsen
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States.,Medicinal Chemistry Core, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - David R Stuart
- Department of Chemistry, Portland State University, 1719 SW 10 Avenue, Portland, Oregon 97201, United States
| | - J Stone Doggett
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States.,School of Medicine Division of Infectious Diseases, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Michael K Riscoe
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States.,Department of Microbiology and Molecular Immunology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Rolf W Winter
- VA Portland Healthcare System, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
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6
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Smilkstein MJ, Pou S, Krollenbrock A, Bleyle LA, Dodean RA, Frueh L, Hinrichs DJ, Li Y, Martinson T, Munar MY, Winter RW, Bruzual I, Whiteside S, Nilsen A, Koop DR, Kelly JX, Kappe SHI, Wilder BK, Riscoe MK. ELQ-331 as a prototype for extremely durable chemoprotection against malaria. Malar J 2019; 18:291. [PMID: 31455339 PMCID: PMC6712883 DOI: 10.1186/s12936-019-2921-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/17/2019] [Indexed: 12/02/2022] Open
Abstract
Background The potential benefits of long-acting injectable chemoprotection (LAI-C) against malaria have been recently recognized, prompting a call for suitable candidate drugs to help meet this need. On the basis of its known pharmacodynamic and pharmacokinetic profiles after oral dosing, ELQ-331, a prodrug of the parasite mitochondrial electron transport inhibitor ELQ-300, was selected for study of pharmacokinetics and efficacy as LAI-C in mice. Methods Four trials were conducted in which mice were injected with a single intramuscular dose of ELQ-331 or other ELQ-300 prodrugs in sesame oil with 1.2% benzyl alcohol; the ELQ-300 content of the doses ranged from 2.5 to 30 mg/kg. Initial blood stage challenges with Plasmodium yoelii were used to establish the model, but the definitive study measure of efficacy was outcome after sporozoite challenge with a luciferase-expressing P. yoelii, assessed by whole-body live animal imaging. Snapshot determinations of plasma ELQ-300 concentration ([ELQ-300]) were made after all prodrug injections; after the highest dose of ELQ-331 (equivalent to 30 mg/kg ELQ-300), both [ELQ-331] and [ELQ-300] were measured at a series of timepoints from 6 h to 5½ months after injection. Results A single intramuscular injection of ELQ-331 outperformed four other ELQ-300 prodrugs and, at a dose equivalent to 30 mg/kg ELQ-300, protected mice against challenge with P. yoelii sporozoites for at least 4½ months. Pharmacokinetic evaluation revealed rapid and essentially complete conversion of ELQ-331 to ELQ-300, a rapidly achieved (< 6 h) and sustained (4–5 months) effective plasma ELQ-300 concentration, maximum ELQ-300 concentrations far below the estimated threshold for toxicity, and a distinctive ELQ-300 concentration versus time profile. Pharmacokinetic modeling indicates a high-capacity, slow-exchange tissue compartment which serves to accumulate and then slowly redistribute ELQ-300 into blood, and this property facilitates an extremely long period during which ELQ-300 concentration is sustained above a minimum fully-protective threshold (60–80 nM). Conclusions Extrapolation of these results to humans predicts that ELQ-331 should be capable of meeting and far-exceeding currently published duration-of-effect goals for anti-malarial LAI-C. Furthermore, the distinctive pharmacokinetic profile of ELQ-300 after treatment with ELQ-331 may facilitate durable protection and enable protection for far longer than 3 months. These findings suggest that ELQ-331 warrants consideration as a leading prototype for LAI-C.
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Affiliation(s)
- Martin J Smilkstein
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA.
| | - Sovitj Pou
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA
| | - Alina Krollenbrock
- Department of Physiology and Pharmacology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Lisa A Bleyle
- Bioanalytical Shared Resource Core Pharmacokinetics, Department of Physiology and Pharmacology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, L334, Portland, OR, 97239, USA
| | - Rozalia A Dodean
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA.,Department of Chemistry, Portland State University, PO Box 751, Portland, OR, 97207, USA
| | - Lisa Frueh
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA
| | - David J Hinrichs
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA
| | - Yuexin Li
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA
| | - Thomas Martinson
- Vaccine & Gene Therapy Institute (VGTI), Oregon Health and Science University (West Campus), 505 NW 185th Avenue, #1, Beaverton, OR, 97006, USA
| | - Myrna Y Munar
- Oregon State University/Oregon Health and Science University College of Pharmacy, 2730 SW Moody Avenue, CL5CP, Portland, OR, 97201, USA
| | - Rolf W Winter
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA.,Department of Chemistry, Portland State University, PO Box 751, Portland, OR, 97207, USA
| | - Igor Bruzual
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA
| | - Samantha Whiteside
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, 307 Westlake Ave N., Suite 500, Seattle, WA, USA
| | - Aaron Nilsen
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA
| | - Dennis R Koop
- Bioanalytical Shared Resource Core Pharmacokinetics, Department of Physiology and Pharmacology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, L334, Portland, OR, 97239, USA
| | - Jane X Kelly
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA.,Department of Chemistry, Portland State University, PO Box 751, Portland, OR, 97207, USA
| | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, 307 Westlake Ave N., Suite 500, Seattle, WA, USA
| | - Brandon K Wilder
- Vaccine & Gene Therapy Institute (VGTI), Oregon Health and Science University (West Campus), 505 NW 185th Avenue, #1, Beaverton, OR, 97006, USA
| | - Michael K Riscoe
- VA Portland Health Care System Research and Development Service, 3710 SW US Veterans Hospital Road, RD-33, Portland, OR, 97239, USA.,Department of Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
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7
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Dodean RA, Kancharla P, Li Y, Melendez V, Read L, Bane CE, Vesely B, Kreishman-Deitrick M, Black C, Li Q, Sciotti RJ, Olmeda R, Luong TL, Gaona H, Potter B, Sousa J, Marcsisin S, Caridha D, Xie L, Vuong C, Zeng Q, Zhang J, Zhang P, Lin H, Butler K, Roncal N, Gaynor-Ohnstad L, Leed SE, Nolan C, Huezo SJ, Rasmussen SA, Stephens MT, Tan JC, Cooper RA, Smilkstein MJ, Pou S, Winter RW, Riscoe MK, Kelly JX. Discovery and Structural Optimization of Acridones as Broad-Spectrum Antimalarials. J Med Chem 2019; 62:3475-3502. [PMID: 30852885 DOI: 10.1021/acs.jmedchem.8b01961] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Malaria remains one of the deadliest diseases in the world today. Novel chemoprophylactic and chemotherapeutic antimalarials are needed to support the renewed eradication agenda. We have discovered a novel antimalarial acridone chemotype with dual-stage activity against both liver-stage and blood-stage malaria. Several lead compounds generated from structural optimization of a large library of novel acridones exhibit efficacy in the following systems: (1) picomolar inhibition of in vitro Plasmodium falciparum blood-stage growth against multidrug-resistant parasites; (2) curative efficacy after oral administration in an erythrocytic Plasmodium yoelii murine malaria model; (3) prevention of in vitro Plasmodium berghei sporozoite-induced development in human hepatocytes; and (4) protection of in vivo P. berghei sporozoite-induced infection in mice. This study offers the first account of liver-stage antimalarial activity in an acridone chemotype. Details of the design, chemistry, structure-activity relationships, safety, metabolic/pharmacokinetic studies, and mechanistic investigation are presented herein.
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Affiliation(s)
- Rozalia A Dodean
- Department of Chemistry , Portland State University , Portland , Oregon 97201 , United States.,Department of Veterans Affairs Medical Center , Portland , Oregon 97239 , United States
| | - Papireddy Kancharla
- Department of Chemistry , Portland State University , Portland , Oregon 97201 , United States
| | - Yuexin Li
- Department of Chemistry , Portland State University , Portland , Oregon 97201 , United States.,Department of Veterans Affairs Medical Center , Portland , Oregon 97239 , United States
| | - Victor Melendez
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Lisa Read
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Charles E Bane
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Brian Vesely
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Mara Kreishman-Deitrick
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Chad Black
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Qigui Li
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Richard J Sciotti
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Raul Olmeda
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Thu-Lan Luong
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Heather Gaona
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Brittney Potter
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Jason Sousa
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Sean Marcsisin
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Diana Caridha
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Lisa Xie
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Chau Vuong
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Qiang Zeng
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Jing Zhang
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Ping Zhang
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Hsiuling Lin
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Kirk Butler
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Norma Roncal
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Lacy Gaynor-Ohnstad
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Susan E Leed
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Christina Nolan
- Division of Experimental Therapeutics , Walter Reed Army Institute of Research , Silver Spring , Maryland 20910 , United States
| | - Stephanie J Huezo
- Department of Natural Sciences and Mathematics , Dominican University of California , San Rafael , California 94901 , United States
| | - Stephanie A Rasmussen
- Department of Natural Sciences and Mathematics , Dominican University of California , San Rafael , California 94901 , United States
| | | | | | - Roland A Cooper
- Department of Natural Sciences and Mathematics , Dominican University of California , San Rafael , California 94901 , United States
| | - Martin J Smilkstein
- Department of Veterans Affairs Medical Center , Portland , Oregon 97239 , United States
| | - Sovitj Pou
- Department of Veterans Affairs Medical Center , Portland , Oregon 97239 , United States
| | - Rolf W Winter
- Department of Chemistry , Portland State University , Portland , Oregon 97201 , United States.,Department of Veterans Affairs Medical Center , Portland , Oregon 97239 , United States
| | - Michael K Riscoe
- Department of Chemistry , Portland State University , Portland , Oregon 97201 , United States.,Department of Veterans Affairs Medical Center , Portland , Oregon 97239 , United States
| | - Jane X Kelly
- Department of Chemistry , Portland State University , Portland , Oregon 97201 , United States.,Department of Veterans Affairs Medical Center , Portland , Oregon 97239 , United States
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8
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Frueh L, Li Y, Mather MW, Li Q, Pou S, Nilsen A, Winter RW, Forquer IP, Pershing AM, Xie LH, Smilkstein MJ, Caridha D, Koop DR, Campbell RF, Sciotti RJ, Kreishman-Deitrick M, Kelly JX, Vesely B, Vaidya AB, Riscoe MK. Alkoxycarbonate Ester Prodrugs of Preclinical Drug Candidate ELQ-300 for Prophylaxis and Treatment of Malaria. ACS Infect Dis 2017; 3:728-735. [PMID: 28927276 DOI: 10.1021/acsinfecdis.7b00062] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ELQ-300 is a preclinical antimalarial drug candidate that is active against liver, blood, and transmission stages of Plasmodium falciparum. While ELQ-300 is highly effective when administered in a low multidose regimen, poor aqueous solubility and high crystallinity have hindered its clinical development. To overcome its challenging physiochemical properties, a number of bioreversible alkoxycarbonate ester prodrugs of ELQ-300 were synthesized. These bioreversible prodrugs are converted to ELQ-300 by host and parasite esterase action in the liver and bloodstream of the host. One such alkoxycarbonate prodrug, ELQ-331, is curative against Plasmodium yoelii with a single low dose of 3 mg/kg in a murine model of patent malaria infection. ELQ-331 is at least as fully protective as ELQ-300 in a murine malaria prophylaxis model when delivered 24 h before sporozoite inoculation at an oral dose of 1 mg/kg. Here, we show that ELQ-331 is a promising prodrug of ELQ-300 with improved physiochemical and metabolic properties and excellent potential for clinical formulation.
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Affiliation(s)
- Lisa Frueh
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
- Department of Molecular Microbiology and
Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Yuexin Li
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Michael W. Mather
- Department
of Microbiology and Immunology, Drexel University, 2900 W. Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Qigui Li
- Experimental
Therapeutics Branch, Military Malaria Research Program (MMRP), Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Sovitj Pou
- Department of Molecular Microbiology and
Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Aaron Nilsen
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Rolf W. Winter
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Isaac P. Forquer
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - April M. Pershing
- Department
of Microbiology and Immunology, Drexel University, 2900 W. Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Lisa H. Xie
- Experimental
Therapeutics Branch, Military Malaria Research Program (MMRP), Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Martin J. Smilkstein
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Diana Caridha
- Experimental
Therapeutics Branch, Military Malaria Research Program (MMRP), Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Dennis R. Koop
- Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Robert F. Campbell
- Experimental
Therapeutics Branch, Military Malaria Research Program (MMRP), Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Richard J. Sciotti
- Experimental
Therapeutics Branch, Military Malaria Research Program (MMRP), Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Mara Kreishman-Deitrick
- Experimental
Therapeutics Branch, Military Malaria Research Program (MMRP), Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Jane X. Kelly
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
| | - Brian Vesely
- Experimental
Therapeutics Branch, Military Malaria Research Program (MMRP), Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Akhil B. Vaidya
- Department
of Microbiology and Immunology, Drexel University, 2900 W. Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Michael K. Riscoe
- Experimental Chemotherapy Laboratory, VA Medical Center (Mail code RD-33), 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
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9
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Foss MH, Pou S, Davidson PM, Dunaj JL, Winter RW, Pou S, Licon MH, Doh JK, Li Y, Kelly JX, Dodean RA, Koop DR, Riscoe MK, Purdy GE. Diphenylether-Modified 1,2-Diamines with Improved Drug Properties for Development against Mycobacterium tuberculosis. ACS Infect Dis 2016; 2:500-8. [PMID: 27626102 DOI: 10.1021/acsinfecdis.6b00052] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
New treatments for tuberculosis infection are critical to combat the emergence of multidrug- and extensively drug-resistant Mycobacterium tuberculosis (Mtb). We report the characterization of a diphenylether-modified adamantyl 1,2-diamine that we refer to as TBL-140, which has a minimal inhibitory concentration (MIC99) of 1.2 μg/mL. TBL-140 is effective against drug-resistant Mtb and nonreplicating bacteria. In addition, TBL-140 eliminates expansion of Mtb in cell culture infection assays at its MIC. To define the mechanism of action of this compound, we performed a spontaneous mutant screen and biochemical assays. We determined that TBL-140 treatment affects the proton motive force (PMF) by perturbing the transmembrane potential (ΔΨ), consistent with a target in the electron transport chain (ETC). As a result, treated bacteria have reduced intracellular ATP levels. We show that TBL-140 exhibits greater metabolic stability than SQ109, a structurally similar compound in clinical trials for treatment of MDR-TB infections. Combined, these results suggest that TBL-140 should be investigated further to assess its potential as an improved therapeutic lead against Mtb.
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Affiliation(s)
- Marie H. Foss
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Sovitj Pou
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Patrick M. Davidson
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Jennifer L. Dunaj
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Rolf W. Winter
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Sovijja Pou
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Meredith H. Licon
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Julia K. Doh
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Yuexin Li
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Jane X. Kelly
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Rozalia A. Dodean
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Dennis R. Koop
- Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Michael K. Riscoe
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Georgiana E. Purdy
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
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10
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Lawres LA, Garg A, Kumar V, Bruzual I, Forquer IP, Renard I, Virji AZ, Boulard P, Rodriguez EX, Allen AJ, Pou S, Wegmann KW, Winter RW, Nilsen A, Mao J, Preston DA, Belperron AA, Bockenstedt LK, Hinrichs DJ, Riscoe MK, Doggett JS, Ben Mamoun C. Radical cure of experimental babesiosis in immunodeficient mice using a combination of an endochin-like quinolone and atovaquone. J Exp Med 2016; 213:1307-18. [PMID: 27270894 PMCID: PMC4925016 DOI: 10.1084/jem.20151519] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 04/25/2016] [Indexed: 01/24/2023] Open
Abstract
Human babesiosis is a tick-borne multisystem disease caused by Babesia species of the apicomplexan phylum. Most clinical cases and fatalities of babesiosis are caused by Babesia microti Current treatment for human babesiosis consists of two drug combinations, atovaquone + azithromycin or quinine + clindamycin. These treatments are associated with adverse side effects and a significant rate of drug failure. Here, we provide evidence for radical cure of experimental babesiosis in immunodeficient mice using a combination of an endochin-like quinolone (ELQ) prodrug and atovaquone. In vivo efficacy studies in mice using ELQ-271, ELQ-316, and the ELQ-316 prodrug, ELQ-334, demonstrated excellent growth inhibitory activity against the parasite, with potency equal to that of orally administered atovaquone at 10 mg/kg. Analysis of recrudescent parasites after ELQ or atovaquone monotherapy identified genetic substitutions in the Qi or Qo sites, respectively, of the cytochrome bc1 complex. Impressively, a combination of ELQ-334 and atovaquone, at doses as low as 5.0 mg/kg each, resulted in complete clearance of the parasite with no recrudescence up to 122 d after discontinuation of therapy. These results will set the stage for future clinical evaluation of ELQ and atovaquone combination therapy for treatment of human babesiosis.
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Affiliation(s)
- Lauren A Lawres
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Aprajita Garg
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Vidya Kumar
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Igor Bruzual
- Veterans Affairs Medical Center, Portland, OR 97239
| | | | - Isaline Renard
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Azan Z Virji
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Pierre Boulard
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Eduardo X Rodriguez
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Alexander J Allen
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Sovitj Pou
- Veterans Affairs Medical Center, Portland, OR 97239
| | | | | | - Aaron Nilsen
- Veterans Affairs Medical Center, Portland, OR 97239
| | - Jialing Mao
- Department of Internal Medicine, Section of Rheumatology, Yale School of Medicine, New Haven, CT 06520
| | | | - Alexia A Belperron
- Department of Internal Medicine, Section of Rheumatology, Yale School of Medicine, New Haven, CT 06520
| | - Linda K Bockenstedt
- Department of Internal Medicine, Section of Rheumatology, Yale School of Medicine, New Haven, CT 06520
| | | | | | | | - Choukri Ben Mamoun
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
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11
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Stickles AM, Ting LM, Morrisey JM, Li Y, Mather MW, Meermeier E, Pershing AM, Forquer IP, Miley GP, Pou S, Winter RW, Hinrichs DJ, Kelly JX, Kim K, Vaidya AB, Riscoe MK, Nilsen A. Inhibition of cytochrome bc1 as a strategy for single-dose, multi-stage antimalarial therapy. Am J Trop Med Hyg 2015; 92:1195-201. [PMID: 25918204 PMCID: PMC4458825 DOI: 10.4269/ajtmh.14-0553] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 02/13/2015] [Indexed: 11/07/2022] Open
Abstract
Single-dose therapies for malaria have been proposed as a way to reduce the cost and increase the effectiveness of antimalarial treatment. However, no compound to date has shown single-dose activity against both the blood-stage Plasmodium parasites that cause disease and the liver-stage parasites that initiate malaria infection. Here, we describe a subset of cytochrome bc1 (cyt bc1) inhibitors, including the novel 4(1H)-quinolone ELQ-400, with single-dose activity against liver, blood, and transmission-stage parasites in mouse models of malaria. Although cyt bc1 inhibitors are generally classified as slow-onset antimalarials, we found that a single dose of ELQ-400 rapidly induced stasis in blood-stage parasites, which was associated with a rapid reduction in parasitemia in vivo. ELQ-400 also exhibited a low propensity for drug resistance and was active against atovaquone-resistant P. falciparum strains with point mutations in cyt bc1. Ultimately, ELQ-400 shows that cyt bc1 inhibitors can function as single-dose, blood-stage antimalarials and is the first compound to provide combined treatment, prophylaxis, and transmission blocking activity for malaria after a single oral administration. This remarkable multi-stage efficacy suggests that metabolic therapies, including cyt bc1 inhibitors, may be valuable additions to the collection of single-dose antimalarials in current development.
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Affiliation(s)
- Allison M Stickles
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Li-Min Ting
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Joanne M Morrisey
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Yuexin Li
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Michael W Mather
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Erin Meermeier
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - April M Pershing
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Isaac P Forquer
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Galen P Miley
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Sovitj Pou
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Rolf W Winter
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - David J Hinrichs
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Jane X Kelly
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Kami Kim
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Akhil B Vaidya
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Michael K Riscoe
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
| | - Aaron Nilsen
- Departments of Physiology and Pharmacology, Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon; Departments of Medicine, Pathology, and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York; Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania; VA Medical Center, Portland, Oregon
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12
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Nilsen A, Miley GP, Forquer IP, Mather MW, Katneni K, Li Y, Pou S, Pershing AM, Stickles AM, Ryan E, Kelly JX, Doggett JS, White KL, Hinrichs DJ, Winter RW, Charman SA, Zakharov LN, Bathurst I, Burrows JN, Vaidya AB, Riscoe MK. Discovery, synthesis, and optimization of antimalarial 4(1H)-quinolone-3-diarylethers. J Med Chem 2014; 57:3818-34. [PMID: 24720377 PMCID: PMC4018401 DOI: 10.1021/jm500147k] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The
historical antimalarial compound endochin served as a structural lead
for optimization. Endochin-like quinolones (ELQ) were prepared by
a novel chemical route and assessed for in vitro activity against
multidrug resistant strains of Plasmodium falciparum and against malaria infections in mice. Here we describe the pathway
to discovery of a potent class of orally active antimalarial 4(1H)-quinolone-3-diarylethers. The initial prototype, ELQ-233,
exhibited low nanomolar IC50 values against all tested
strains including clinical isolates harboring resistance to atovaquone.
ELQ-271 represented the next critical step in the iterative optimization
process, as it was stable to metabolism and highly effective in vivo.
Continued analoging revealed that the substitution pattern on the
benzenoid ring of the quinolone core significantly influenced reactivity
with the host enzyme. This finding led to the rational design of highly
selective ELQs with outstanding oral efficacy against murine malaria
that is superior to established antimalarials chloroquine and atovaquone.
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Affiliation(s)
- Aaron Nilsen
- VA Medical Center , 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, United States
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13
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Nilsen A, LaCrue AN, White KL, Forquer IP, Cross RM, Marfurt J, Mather MW, Delves MJ, Shackleford DM, Saenz FE, Morrisey JM, Steuten J, Mutka T, Li Y, Wirjanata G, Ryan E, Duffy S, Kelly JX, Sebayang BF, Zeeman AM, Noviyanti R, Sinden RE, Kocken CHM, Price RN, Avery VM, Angulo-Barturen I, Jiménez-Díaz MB, Ferrer S, Herreros E, Sanz LM, Gamo FJ, Bathurst I, Burrows JN, Siegl P, Guy RK, Winter RW, Vaidya AB, Charman SA, Kyle DE, Manetsch R, Riscoe MK. Quinolone-3-diarylethers: a new class of antimalarial drug. Sci Transl Med 2013; 5:177ra37. [PMID: 23515079 DOI: 10.1126/scitranslmed.3005029] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The goal for developing new antimalarial drugs is to find a molecule that can target multiple stages of the parasite's life cycle, thus impacting prevention, treatment, and transmission of the disease. The 4(1H)-quinolone-3-diarylethers are selective potent inhibitors of the parasite's mitochondrial cytochrome bc1 complex. These compounds are highly active against the human malaria parasites Plasmodium falciparum and Plasmodium vivax. They target both the liver and blood stages of the parasite as well as the forms that are crucial for disease transmission, that is, the gametocytes, the zygote, the ookinete, and the oocyst. Selected as a preclinical candidate, ELQ-300 has good oral bioavailability at efficacious doses in mice, is metabolically stable, and is highly active in blocking transmission in rodent models of malaria. Given its predicted low dose in patients and its predicted long half-life, ELQ-300 has potential as a new drug for the treatment, prevention, and, ultimately, eradication of human malaria.
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Affiliation(s)
- Aaron Nilsen
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Alexis N LaCrue
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Karen L White
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Isaac P Forquer
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Richard M Cross
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620-5250, USA
| | - Jutta Marfurt
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Michael W Mather
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Michael J Delves
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - David M Shackleford
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Fabian E Saenz
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Joanne M Morrisey
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Jessica Steuten
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Tina Mutka
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Yuexin Li
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Grennady Wirjanata
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Eileen Ryan
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Sandra Duffy
- Eskitis Institute for Cell & Molecular Therapies, Brisbane Innovation Park, Nathan campus, Griffith University, QLD 4111, Australia
| | - Jane Xu Kelly
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Boni F Sebayang
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Anne-Marie Zeeman
- Department of Parasitology, Biomedical Primate Research Centre, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Rintis Noviyanti
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Robert E Sinden
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Centre, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Ric N Price
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia.,Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7LJ, UK
| | - Vicky M Avery
- Eskitis Institute for Cell & Molecular Therapies, Brisbane Innovation Park, Nathan campus, Griffith University, QLD 4111, Australia
| | - Iñigo Angulo-Barturen
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - María Belén Jiménez-Díaz
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Santiago Ferrer
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Esperanza Herreros
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Laura M Sanz
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Francisco-Javier Gamo
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Ian Bathurst
- Medicines for Malaria Venture, 20, route de Pré-Bois, PO Box 1826, 1215 Geneva 15, Switzerland
| | - Jeremy N Burrows
- Medicines for Malaria Venture, 20, route de Pré-Bois, PO Box 1826, 1215 Geneva 15, Switzerland
| | - Peter Siegl
- Siegl Pharma Consulting LLC, Blue Bell, PA, USA
| | - R Kiplin Guy
- Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105-3678 USA
| | - Rolf W Winter
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Akhil B Vaidya
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Susan A Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Dennis E Kyle
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Roman Manetsch
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620-5250, USA
| | - Michael K Riscoe
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA.,Department of Molecular Microbiology and Immunology, 3181 Sam Jackson Blvd., Portland, Oregon 97239, USA
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14
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Pou S, Winter RW, Nilsen A, Kelly JX, Li Y, Doggett JS, Riscoe EW, Wegmann KW, Hinrichs DJ, Riscoe MK. Sontochin as a guide to the development of drugs against chloroquine-resistant malaria. Antimicrob Agents Chemother 2012; 56:3475-80. [PMID: 22508305 PMCID: PMC3393441 DOI: 10.1128/aac.00100-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 04/09/2012] [Indexed: 11/20/2022] Open
Abstract
Sontochin was the original chloroquine replacement drug, arising from research by Hans Andersag 2 years after chloroquine (known as "resochin" at the time) had been shelved due to the mistaken perception that it was too toxic for human use. We were surprised to find that sontochin, i.e., 3-methyl-chloroquine, retains significant activity against chloroquine-resistant strains of Plasmodium falciparum in vitro. We prepared derivatives of sontochin, "pharmachins," with alkyl or aryl substituents at the 3 position and with alterations to the 4-position side chain to enhance activity against drug-resistant strains. Modified with an aryl substituent in the 3 position of the 7-chloro-quinoline ring, Pharmachin 203 (PH-203) exhibits low-nanomolar 50% inhibitory concentrations (IC(50)s) against drug-sensitive and multidrug-resistant strains and in vivo efficacy against patent infections of Plasmodium yoelii in mice that is superior to chloroquine. Our findings suggest that novel 3-position aryl pharmachin derivatives have the potential for use in treating drug resistant malaria.
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Affiliation(s)
- Sovitj Pou
- VA Medical Center, Portland, Oregon, USA
| | - Rolf W. Winter
- VA Medical Center, Portland, Oregon, USA
- Department of Chemistry, Portland State University, Portland, Oregon, USA
| | | | - Jane Xu Kelly
- VA Medical Center, Portland, Oregon, USA
- Department of Chemistry, Portland State University, Portland, Oregon, USA
| | - Yuexin Li
- VA Medical Center, Portland, Oregon, USA
| | - J. Stone Doggett
- VA Medical Center, Portland, Oregon, USA
- Department of Medicine, Division of Infectious Diseases, Oregon Health & Science University, Portland, Oregon, USA
| | - Erin W. Riscoe
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | | | - David J. Hinrichs
- VA Medical Center, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Michael K. Riscoe
- VA Medical Center, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Department of Chemistry, Portland State University, Portland, Oregon, USA
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15
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Dodean RA, Kelly JX, Peyton D, Gard GL, Riscoe MK, Winter RW. Synthesis and heme-binding correlation with antimalarial activity of 3,6-bis-(ω-N,N-diethylaminoamyloxy)-4,5-difluoroxanthone. Bioorg Med Chem 2008; 16:1174-83. [DOI: 10.1016/j.bmc.2007.10.083] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2007] [Revised: 10/19/2007] [Accepted: 10/23/2007] [Indexed: 10/22/2022]
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16
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Smilkstein MJ, Forquer I, Kanazawa A, Kelly JX, Winter RW, Hinrichs DJ, Kramer DM, Riscoe MK. A drug-selected Plasmodium falciparum lacking the need for conventional electron transport. Mol Biochem Parasitol 2008; 159:64-8. [PMID: 18308406 DOI: 10.1016/j.molbiopara.2008.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 01/11/2008] [Accepted: 01/15/2008] [Indexed: 10/22/2022]
Abstract
Mitochondrial electron transport is essential for survival in Plasmodium falciparum, making the cytochrome (cyt) bc(1) complex an attractive target for antimalarial drug development. Here we report that P. falciparum cultivated in the presence of a novel cyt bc(1) inhibitor underwent a fundamental transformation in biochemistry to a phenotype lacking a requirement for electron transport through the cyt bc(1) complex. Growth of the drug-selected parasite clone (SB1-A6) is robust in the presence of diverse cyt bc(1) inhibitors, although electron transport is fully inhibited by these same agents. This transformation defies expected molecular-based concepts of drug resistance, has important implications for the study of cyt bc(1) as an antimalarial drug target, and may offer a glimpse into the evolutionary future of Plasmodium.
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Affiliation(s)
- Martin J Smilkstein
- Medical Research Service, Department of Veterans Affairs Medical Center, Portland, OR 97239, USA.
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17
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Ye C, Gard GL, Winter RW, Syvret RG, Twamley B, Shreeve JM. Synthesis of Pentafluorosulfanylpyrazole and Pentafluorosulfanyl-1,2,3-triazole and Their Derivatives as Energetic Materials by Click Chemistry. Org Lett 2007; 9:3841-4. [PMID: 17715932 DOI: 10.1021/ol701602a] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1-Pentafluorosulfanyl acetylene and its derivatives react with azide or diazomethane giving rise to an SF5-substituted 1,2,3-triazole or pyrazole. The SF5 group increases density remarkably and as a result enhances the detonation performance of the energetic materials relative to the CF3 group.
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Affiliation(s)
- Chengfeng Ye
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA
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18
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19
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Kelly JX, Winter RW, Braun TP, Osei-Agyemang M, Hinrichs DJ, Riscoe MK. Selective killing of the human malaria parasite Plasmodium falciparum by a benzylthiazolium dye. Exp Parasitol 2006; 116:103-10. [PMID: 17266952 PMCID: PMC1965281 DOI: 10.1016/j.exppara.2006.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 11/30/2006] [Accepted: 12/06/2006] [Indexed: 11/25/2022]
Abstract
Malaria is an infectious disease caused by protozoan parasites of the genus Plasmodium. The most virulent form of the disease is caused by Plasmodium falciparum which infects hundreds of millions of people and is responsible for the deaths of 1-2 million individuals each year. An essential part of the parasitic process is the remodeling of the red blood cell membrane and its protein constituents to permit a higher flux of nutrients and waste products into or away from the intracellular parasite. Much of this increased permeability is due to a single type of broad specificity channel variously called the new permeation pathway (NPP), the nutrient channel, and the Plasmodial surface anion channel (PSAC). This channel is permeable to a range of low molecular weight solutes both charged and uncharged, with a strong preference for anions. Drugs such as furosemide that are known to block anion-selective channels inhibit PSAC. In this study, we have investigated a dye known as benzothiocarboxypurine, BCP, which had been studied as a possible diagnostic aid given its selective uptake by P. falciparum infected red cells. We found that the dye enters parasitized red cells via the furosemide-inhibitable PSAC, forms a brightly fluorescent complex with parasite nucleic acids, and is selectively toxic to infected cells. Our study describes an antimalarial agent that exploits the altered permeability of Plasmodium-infected red cells as a means to killing the parasite and highlights a chemical reagent that may prove useful in high throughput screening of compounds for inhibitors of the channel.
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Affiliation(s)
- Jane X. Kelly
- Medical Research Service, RD-33, Department of Veterans Affairs Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR, USA 97239
- Department of Chemistry, Portland State University, Portland, Oregon, 97207-0751
| | - Rolf W. Winter
- Medical Research Service, RD-33, Department of Veterans Affairs Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR, USA 97239
- Department of Chemistry, Portland State University, Portland, Oregon, 97207-0751
| | - Theodore P. Braun
- Medical Research Service, RD-33, Department of Veterans Affairs Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR, USA 97239
| | - Myralyn Osei-Agyemang
- Medical Research Service, RD-33, Department of Veterans Affairs Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR, USA 97239
| | - David J. Hinrichs
- Medical Research Service, RD-33, Department of Veterans Affairs Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR, USA 97239
| | - Michael K. Riscoe
- Medical Research Service, RD-33, Department of Veterans Affairs Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR, USA 97239
- Department of Chemistry, Portland State University, Portland, Oregon, 97207-0751
- Mailing Address: *Michael Riscoe, Ph.D., Medical Research Service, RD-33, Veterans Affairs Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, Oregon 97239 Phone Number: 503-721-7885/Telefacsimile: 503-402-2817/e-mail:
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20
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Dolbier WR, Aït-Mohand S, Schertz TD, Sergeeva TA, Cradlebaugh JA, Mitani A, Gard GL, Winter RW, Thrasher JS. A convenient and efficient method for incorporation of pentafluorosulfanyl (SF5) substituents into aliphatic compounds. J Fluor Chem 2006. [DOI: 10.1016/j.jfluchem.2006.05.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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22
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Winter RW, Kelly JX, Smilkstein MJ, Dodean R, Bagby GC, Rathbun RK, Levin JI, Hinrichs D, Riscoe MK. Evaluation and lead optimization of anti-malarial acridones. Exp Parasitol 2006; 114:47-56. [PMID: 16828746 DOI: 10.1016/j.exppara.2006.03.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2005] [Revised: 03/27/2006] [Accepted: 03/28/2006] [Indexed: 02/06/2023]
Abstract
With 2-methoxy-6-chloroacridone as a lead compound, we synthesized and tested acridone derivatives to develop a better understanding of the anti-malarial structure-activity relationships. Over 30 acridone derivatives were synthesized. The most potent compounds contained extended alkyl chains terminated by trifluoromethyl groups and located at the 3-position of the tricyclic system. Acridones optimized in the length of the side chain and the nature of the terminal fluorinated moiety exhibited in vitro anti-malarial IC(50) values in the low nanomolar and picomolar range and were without cytotoxic effects on the proliferation and differentiation of human bone marrow progenitors or mitogen-activated murine lymphocytes at concentrations up to 100,000-fold higher. Based on a structural similarity to known anti-malarial agents it is proposed that the haloalkoxyacridones exert their anti-malarial effects through inhibition of the Plasmodium cytochrome bc(1) complex. Haloalkoxyacridones represent an extraordinarily potent novel class of chemical compounds with the potential for development as therapeutic agents to treat or prevent malaria in humans.
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Affiliation(s)
- Rolf W Winter
- Medical Research Service, RD-33, VA Medical Center, 3710 SW U.S. Veterans Hospital Road, Portland, OR 97239, USA
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23
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Winner SW, Winter RW, Smith JA, Gard GL, Hannah NA, Rananavare SB, Piknova B, Hall SB. Aromatic pentafluoro-λ6-sulfanyl (SF5) surfactants: m-SF5(CF2)nC6H4SO3K. Mendeleev Communications 2006. [DOI: 10.1070/mc2006v016n03abeh002315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Smith JA, DiStasio RA, Hannah NA, Winter RW, Weakley TJR, Gard GL, Rananavare SB. SF5-Terminated Fluorinated Schiff Base Liquid Crystals. J Phys Chem B 2004. [DOI: 10.1021/jp047732o] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeremy A. Smith
- Department of Chemistry, Portland State University, 1719 SW 10th Ave., Room 238C, Portland, Oregon 97207; Department of Electrical and Computer Engineering, OGI School of Science and Technology at Oregon Health & Science University, 20000 NW Walker Road, Beaverton, Oregon 97006; and Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403
| | - Robert A. DiStasio
- Department of Chemistry, Portland State University, 1719 SW 10th Ave., Room 238C, Portland, Oregon 97207; Department of Electrical and Computer Engineering, OGI School of Science and Technology at Oregon Health & Science University, 20000 NW Walker Road, Beaverton, Oregon 97006; and Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403
| | - Nicole A. Hannah
- Department of Chemistry, Portland State University, 1719 SW 10th Ave., Room 238C, Portland, Oregon 97207; Department of Electrical and Computer Engineering, OGI School of Science and Technology at Oregon Health & Science University, 20000 NW Walker Road, Beaverton, Oregon 97006; and Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403
| | - Rolf W. Winter
- Department of Chemistry, Portland State University, 1719 SW 10th Ave., Room 238C, Portland, Oregon 97207; Department of Electrical and Computer Engineering, OGI School of Science and Technology at Oregon Health & Science University, 20000 NW Walker Road, Beaverton, Oregon 97006; and Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403
| | - Timothy J. R. Weakley
- Department of Chemistry, Portland State University, 1719 SW 10th Ave., Room 238C, Portland, Oregon 97207; Department of Electrical and Computer Engineering, OGI School of Science and Technology at Oregon Health & Science University, 20000 NW Walker Road, Beaverton, Oregon 97006; and Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403
| | - Gary L. Gard
- Department of Chemistry, Portland State University, 1719 SW 10th Ave., Room 238C, Portland, Oregon 97207; Department of Electrical and Computer Engineering, OGI School of Science and Technology at Oregon Health & Science University, 20000 NW Walker Road, Beaverton, Oregon 97006; and Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403
| | - Shankar B. Rananavare
- Department of Chemistry, Portland State University, 1719 SW 10th Ave., Room 238C, Portland, Oregon 97207; Department of Electrical and Computer Engineering, OGI School of Science and Technology at Oregon Health & Science University, 20000 NW Walker Road, Beaverton, Oregon 97006; and Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403
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25
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Marracci GH, McKeon GP, Marquardt WE, Winter RW, Riscoe MK, Bourdette DN. ? lipoic acid inhibits human T-cell migration: Implications for multiple sclerosis. J Neurosci Res 2004; 78:362-70. [PMID: 15389837 DOI: 10.1002/jnr.20255] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have demonstrated previously the ability of the antioxidant alpha lipoic acid (ALA) to suppress and treat a model of multiple sclerosis (MS), relapsing experimental autoimmune encephalomyelitis (EAE). We describe the effects of ALA and its reduced form, dihydrolipoic acid (DHLA), on the transmigration of human Jurkat T cells across a fibronectin barrier in a transwell system. ALA and DHLA inhibited migration of Jurkat cells in a dose-dependent fashion by 16-75%. ALA and DHLA reduced matrix metalloproteinase-9 (MMP-9) activity by 18-90% in Jurkat cell supernatants. GM6001, a synthetic inhibitor of MMP, reduced Jurkat cell migration, but not as effectively as ALA and DHLA did. Both ALA and DHLA downmodulated the surface expression of the alpha4beta1 integrin (very late activation-4 antigen; VLA-4), which binds fibronectin and its endothelial cell ligand vascular cell adhesion molecule-1 (VCAM-1). Moreover, ALA, but not DHLA, reduced MMP-9-specific mRNA and extracellular MMP-9 from Jurkat cells and their culture supernatants as detected by relative reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. ALA and DHLA inhibited Jurkat cell migration and have different mechanisms for inhibiting MMP-9 activity. These data, coupled with its ability to treat relapsing EAE, suggest that ALA warrants investigation as a therapy for MS.
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Affiliation(s)
- Gail H Marracci
- Portland Veterans Affairs Medical Center, Portland, Oregon, USA
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26
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Abstract
The first quaternary salts of pyridine (2), N-methyl imidazole (3), N-propyl triazole (4), and pyridazine (5) that contain the pentafluorosulfanyl (SF(5)) group were prepared and characterized. Neat reactions of the aromatic nitrogen compounds with SF(5)(CF(2))(n)(CH(2))(m)I (n = 2 or 4, m = 2 or 4) gave quaternary iodides 6a-c, 7a-c, 8a, and 9a,b, which were metathesized with LiN(SO(2)CF(3))(2) to form the bis(trifluoromethylsulfonyl)amides 10a-c, 11a-c, 12a, and 13a,b, in high yields. With the exception of the pyridine bis(trifluoromethylsulfonyl)amide salts, the compounds melted or exhibited a T(g) at <0 degrees C. The methylimidazolium, pyridinium, and pyridazinium salts exhibited densities of approximately 2 g/cm(3). Particularly striking was the density of CF(3)(CF(2))(5)(CH(2))(2)-pyridazinium N(CF(3)SO(2))(2) measured at 2.13 g/cm(3); however, an atypically high density for the 1-CF(3)(CF(2))(5)(CH(2))(2)-3-methyl imidazolium amide (14) was also observed at 1.77 g/cm(3). All quaternary salts were characterized via IR, (19)F, (1)H, and (13)C NMR spectra and elemental analyses.
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Affiliation(s)
- Rajendra P Singh
- Department of Chemistry, University of Idaho, Moscow, ID 83844-2343, USA
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27
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Abstract
Core-ionization energies have been measured for SF(6) (S 2p), SF(5)SF(5) (S 2p), SF(5)Br (S 2p and Br 3d), and SF(5)CF(3) (S 2p and C 1s). These results, together with others that establish correlations between core-ionization energies and Pauling electronegativities, make it possible to assign group electronegativities to SF(5) and CF(3). This method gives electronegativities for these groups comparable to that of bromine, whereas analysis of the effect of these groups on acidity indicates electronegativities comparable to that of fluorine. Other methods of estimating electronegativity fall between these extremes. These disparities can be understood in part as reflecting the effects of polarizibility of the substituent, which tends to lower both the core-ionization energy and the deprotonation energy, making the electronegativity appear to be less in one case and more in the other. In addition, and possibly more important, the core-ionization energies presented here reflect the effect of the group on an adjacent atom, whereas the acidity reflects the effect on a remote atom. It appears that fluorine has a large effect on an adjacent atom but a relatively small effect on a remote atom. By contrast SF(5) and CF(3) have a relatively small effect on an adjacent atom, but this effect falls off only slowly with distance from the substituent. Thus, the effective electronegativities of CF(3) and SF(5) relative to those of the halogens depend on the site at which the molecule is probed as well as on the process that is under consideration.
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Affiliation(s)
- Jan E True
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
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28
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Kelly JX, Ignatushchenko MV, Bouwer HG, Peyton DH, Hinrichs DJ, Winter RW, Riscoe M. Antileishmanial drug development: exploitation of parasite heme dependency. Mol Biochem Parasitol 2003; 126:43-9. [PMID: 12554083 DOI: 10.1016/s0166-6851(02)00248-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A rational approach in the search for new antiparasitic drugs is the exploitation of biochemical differences between the parasite and its mammalian host. One specific example in the case of Leishmania relates to the biosynthesis of heme, a critical prosthetic group for proteins involved in metabolism and electron transport. Like all Trypanosomatids, Leishmania parasites require heme or pre-formed porphyrins for survival because they lack several key enzymes in the heme biosynthetic pathway. Considering their specific nutritional requirements, we speculated that they would be particularly sensitive to the effects of heme-complexing xanthones. In this report, we document the antileishmanial activity of selected nitrogenated xanthones and correlate drug potency with heme affinity. In vitro tests demonstrated that 3,6-bis-omega-diethylaminoamyloxyxanthone, C5, was at least 100 times more active than pentamidine against intracellular amastigotes of Leishmania mexicana. Our findings provide practical guidance for optimizing the antileishmanial activity of the xanthone pharmacophore to better exploit parasite heme salvage processes.
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Affiliation(s)
- Jane Xu Kelly
- Department of Chemistry, Portland State University, OR 97207-0751, USA
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29
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Kelly JX, Winter RW, Cornea A, Peyton DH, Hinrichs DJ, Riscoe M. The kinetics of uptake and accumulation of 3,6-bis-omega-diethylamino-amyloxyxanthone by the human malaria parasite Plasmodium falciparum. Mol Biochem Parasitol 2002; 123:47-54. [PMID: 12165388 DOI: 10.1016/s0166-6851(02)00118-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Malarial parasites rely on the digestion of hemoglobin during the intra-erythrocytic stage. The enzymatic degradation of hemoglobin yields amino acids for parasite survival, and free heme which is detoxified by conversion to an aggregate of dimeric heme known as hemozoin. Xanthones have been found to subvert this process by formation of soluble drug-heme complexes. We have optimized the simple hydroxyxanthone structure to include side chains with protonatable nitrogen atoms to enhance interaction with the propionate groups of heme and to target the drug to the parasite digestive vacuole. One member of this optimized class of compounds, 3,6-bis-omega-diethylaminoamyloxyxanthone (C5), was used as a prototype for mechanistic studies. By HPLC analysis we demonstrate that the drug accumulates in the digestive vacuole from 5 to approximately 33,000 microM within 1 h of exposure to parasitized red cells. Confocal fluorescence microscopy was used to visualize the accumulation process directly and to document the colocalization of the drug with the acidophilic dye, LysoTracker Red.
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Affiliation(s)
- Jane Xu Kelly
- Department of Chemistry, Portland State University, Portland, OR 97207-0751, USA
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30
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Marit Trætteberg,*, Richardson AD, Hedberg K, Winter RW, Gard GL. Structure, Conformations, and Internal Hydrogen Bonding in Gaseous 4-Fluorobutan-1-ol. Gas-Phase Electron Diffraction and Ab Initio Study. J Phys Chem A 2001. [DOI: 10.1021/jp012392h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marit Trætteberg,*
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, and Department of Chemistry, Portland State University, Portland, Oregon 97207
| | - Alan D. Richardson
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, and Department of Chemistry, Portland State University, Portland, Oregon 97207
| | - Kenneth Hedberg
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, and Department of Chemistry, Portland State University, Portland, Oregon 97207
| | - Rolf W. Winter
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, and Department of Chemistry, Portland State University, Portland, Oregon 97207
| | - Gary L. Gard
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, and Department of Chemistry, Portland State University, Portland, Oregon 97207
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31
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Nam MS, Ardavan A, Symington JA, Singleton J, Harrison N, Mielke CH, Schlueter JA, Winter RW, Gard GL. Thermal activation between Landau levels in the organic superconductor beta(")-(BEDT-TTF)2SF5CH2CF2SO3. Phys Rev Lett 2001; 87:117001. [PMID: 11531544 DOI: 10.1103/physrevlett.87.117001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2000] [Indexed: 05/23/2023]
Abstract
We show that Shubnikov-de Haas oscillations in the interlayer resistivity of the organic superconductor beta(")-(BEDT-TTF)2SF5CH2CF2SO3 become very pronounced in magnetic fields approximately 60 T. The conductivity minima exhibit thermally activated behavior that can be explained simply by the presence of a Landau gap, with the quasi-one-dimensional Fermi surface sheets contributing negligibly to the conductivity. This observation, together with complete suppression of chemical potential oscillations, is consistent with an incommensurate nesting instability of the quasi-one-dimensional sheets.
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Affiliation(s)
- M S Nam
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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Wosnitza J, Wanka S, Hagel J, Löhneysen H, Qualls JS, Brooks JS, Balthes E, Schlueter JA, Geiser U, Mohtasham J, Winter RW, Gard GL. Field-induced metal-insulator transition in a two-dimensional organic superconductor. Phys Rev Lett 2001; 86:508-511. [PMID: 11177867 DOI: 10.1103/physrevlett.86.508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2000] [Indexed: 05/23/2023]
Abstract
The quasi-two-dimensional organic superconductor beta"-(BEDT-TTF)2SF5CH2CF2SO3 (Tc approximately 4.4 K) shows very strong Shubnikov-de Haas (SdH) oscillations which are superimposed on a highly anomalous steady background magnetoresistance, Rb. Comparison with de Haas-van Alphen oscillations allows a reliable estimate of Rb which is crucial for the correct extraction of the SdH signal. At low temperatures and high magnetic fields insulating behavior evolves. The magnetoresistance data violate Kohler's rule, i.e., cannot be described within the framework of semiclassical transport theory, but converge onto a universal curve appropriate for dynamical scaling at a metal-insulator transition.
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Affiliation(s)
- J Wosnitza
- Physikalisches Institut, Universität Karlsruche, Germany
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Abstract
The erythrocytic development of Plasmodium falciparum is divided into the ring, trophozoite, and schizont stages based on morphologic assessment. Using highly synchronous ring and trophozoite cultures of P. falciparum, we observed considerable differences in their sensitivity to hydroxyxanthones: trophozoites were much more sensitive to the drugs than ring-stage parasites. Trophozoites treated with a prototypic xanthone, the 2,3,4,5,6-pentahydroxy derivative (X5), were arrested in their development and became degenerate in appearance within 24 hr of drug exposure. These morphologic changes appeared to reflect the cytotoxic nature of the action of the drug against the parasite, since daughter ring-stage forms were not observed following addition of the drug. That X5 was more active against parasites in the later stages of intraerythrocytic development is consistent with the proposed mode of action, inhibition of heme polymerization. Knowledge of the structure-activity relationships for xanthones as antimalarial agents has also been expanded. Xanthones with a hydroxyl group in the peri-position exhibited decreased antimalarial activity, possibly due to intramolecular hydrogen bonding with the carbonyl and consequent reduced affinity for heme. Paired hydroxyls attached to the lower half of the xanthone greatly enhanced drug potency.
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Affiliation(s)
- M V Ignatushchenko
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201, USA
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Wang HH, VanZile ML, Schlueter JA, Geiser U, Kini AM, Sche PP, Koo HJ, Whangbo MH, Nixon PG, Winter RW, Gard GL. In-Plane ESR Microwave Conductivity Measurements and Electronic Band Structure Studies of the Organic Superconductor β‘ ‘-(BEDT−TTF)2SF5CH2CF2SO3. J Phys Chem B 1999. [DOI: 10.1021/jp991268j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Winter RW, Ignatushchenko M, Ogundahunsi OA, Cornell KA, Oduola AM, Hinrichs DJ, Riscoe MK. Potentiation of an antimalarial oxidant drug. Antimicrob Agents Chemother 1997; 41:1449-54. [PMID: 9210664 PMCID: PMC163938 DOI: 10.1128/aac.41.7.1449] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In a previous report we described the synergistic antimalarial interaction between two structurally similar compounds, rufigallol and exifone. To explain this phenomenon, we proposed that exifone is transformed inside the parasitized erythrocyte into a xanthone with potent antimalarial properties. We speculated that the transformation process was induced by the prooxidant activity of rufigallol. On the basis of this model we hypothesized that exifone would act synergistically with other oxidant drugs. In the present study we have found a similar synergistic interaction between exifone and ascorbic acid (vitamin C) against both chloroquine-susceptible and multidrug-resistant strains of Plasmodium falciparum. The prooxidant activity of ascorbic acid against Plasmodium-infected erythrocytes is believed to result from an intraerythrocytic Fenton reaction occurring in the acidic food vacuole of the parasite. The hydroxyl radicals produced during this process are believed to attack exifone, which undergoes cyclodehydration to become 2,3,4,5,6-pentahydroxyxanthone (X5). Evidence presented to support this "xanthone hypothesis" includes the demonstration that the exifone ==> X5 transformation occurs readily in vitro under mildly acidic conditions in the presence of iron, ascorbic acid, and oxygen.
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Affiliation(s)
- R W Winter
- Medical Research Service, Department of Veterans' Affairs Medical Center, Portland, Oregon 97201, USA
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Abstract
We recently demonstrated that 2,3,4,5,6-pentahydroxyxanthone (X5) inhibits the in vitro growth of both chloroquine-sensitive and multidrug-resistant strains of P. falciparum. To study the molecular basis of its antimalarial action, we tested X5 and selected hydroxyxanthone analogs as inhibitors of in vitro heme polymerization in a low ionic strength phosphate solution at mildly acidic pH. We found that addition of 1 Eq. of X5 resulted in complete inhibition of polymerization in this system whereas addition of up to 40 Eqs. of standard antimalarial compounds (chloroquine, primaquine, quinacrine, artemisinin and methylene blue) had no such effect although these compounds did co-precipitate with heme. The antimalarial potency of the hydroxyxanthones correlated well with their ability to inhibit in vitro heme polymerization in our assay, suggesting that these compounds exert their antimalarial action by preventing hemozoin formation. Based on the observed structure-activity relationships, we propose a model displaying possible interactions between hydroxyxanthones and heme.
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Affiliation(s)
- M V Ignatushchenko
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201, USA
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Geiser U, Schlueter JA, Wang HH, Kini AM, Williams JM, Sche PP, Zakowicz HI, VanZile ML, Dudek JD, Nixon PG, Winter RW, Gard GL, Ren J, Whangbo MH. Superconductivity at 5.2 K in an Electron Donor Radical Salt of Bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with the Novel Polyfluorinated Organic Anion SF5CH2CF2SO3-. J Am Chem Soc 1996. [DOI: 10.1021/ja962188l] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cornell KA, Winter RW, Tower PA, Riscoe MK. Affinity purification of 5-methylthioribose kinase and 5-methylthioadenosine/S-adenosylhomocysteine nucleosidase from Klebsiella pneumoniae [corrected]. Biochem J 1996; 317 ( Pt 1):285-90. [PMID: 8694776 PMCID: PMC1217475 DOI: 10.1042/bj3170285] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Two enzymes in the methionine salvage pathway, 5-methylthioribose kinase (MTR kinase) and 5'-methylthioadenosine/ S-adenosylhomocysteine nucleosidase (MTA/SAH nucleosidase) were purified from Klebsiella pneumoniae. Chromatography using a novel 5'-(p-aminophenyl)thioadenosine/5-(p-aminophenyl)thioribose affinity matrix allowed the binding and selective elution of each of the enzymes in pure form. The molecular mass, substrate kinetics and N-terminal amino acid sequences were characterized for each of the enzymes. Purified MTR kinase exhibits an apparent molecular mass of 46-50 kDa by SDS/PAGE and S200HR chromatography, and has a Km for MTR of 12.2 microM. Homogeneous MTA/SAH nucleosidase displays a molecular mass of 26.5 kDa by SDS/PAGE, and a Km for MTA of 8.7 microM. Comparisons of the N-terminal sequences obtained for each of the enzymes with protein-sequence databases failed to reveal any significant sequence similarities to known proteins. However, the amino acid sequence obtained for the nucleosidase did share a high degree of sequence similarity with the putative translation product of an open reading frame in Escherichia coli, thus providing a tentative identification of this gene as encoding an MTA/SAH nucleosidase.
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Affiliation(s)
- K A Cornell
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201, USA
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Abstract
OBJECTIVES The purpose of the present study was to modify the filler content of an experimental room-temperature vulcanizing (RTV) lining material that demonstrated high water sorption in order to produce a material with low sorption properties. METHODS Three new formulations were prepared, each containing different hydrophobic silane-treated silica fillers. Water sorption properties for specimens obtained from these formulations were determined using standard experimental techniques. RESULTS All formulations demonstrated greatly reduced water absorption and low volume change. CONCLUSIONS An experimental RTV poly(dimethylsiloxane) denture soft lining material having low water sorption properties has been produced.
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Affiliation(s)
- M G Waters
- Department of Basic Dental Science, Cardiff Dental School, UK
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Winter RW, Cornell KA, Johnson LL, Ignatushchenko M, Hinrichs DJ, Riscoe MK. Potentiation of the antimalarial agent rufigallol. Antimicrob Agents Chemother 1996; 40:1408-11. [PMID: 8726010 PMCID: PMC163340 DOI: 10.1128/aac.40.6.1408] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We have discovered a remarkable synergistic antimalarial interaction between rufigallol and the structurally similar compound exifone. The synergistic effects were produced in chloroquine-susceptible and chloroquine-resistant clones of Plasmodium falciparum. The degree of potentiation as estimated by standard isobolar analysis was approximately 60-fold for experiments initiated with asynchronous parasites. The most pronounced synergism was observed in experiments with synchronized trophozoite-infected erythrocytes, in which the degree of synergy was at least 300-fold. While the mechanism underlying this drug potentiation remains unresolved, it is hypothesized that rufigallol acts in pro-oxidant fashion to produce oxygen radicals inside parasitized erythrocytes. These radicals would attack exifone, thereby initiating its transformation into a more potent compound, a xanthone.
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Affiliation(s)
- R W Winter
- Medical Research Service, Department of Veterans Affairs Medical Center, Portland, Oregon 97201, USA
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Abstract
OBJECTIVES The reason for high water absorption by room temperature vulcanizing (RTV) silicone denture soft lining materials has not been demonstrated previously. An experimental room-temperature vulcanizing (RTV) silicone soft lining material which had been shown to have good mechanical properties had high water absorption at equilibrium whilst losing only small amounts of soluble material after desorption. The volume change in the material was also high. A variety of formulations of the experimental material was devised in order to determine the cause of the high water sorption values. METHODS Water sorption values were determined using standard experimental techniques. Sections of the polymerized materials were examined by scanning electron microscopy for microporosity. RESULTS Neither removal of residual cross-linker nor changing the method of polymerization reduced the water absorption. Scanning electron microscopy did not demonstrate a porous structure of the polymerized material. A correlation was seen between filler content and water absorption. A formulation without filler showed a greatly reduced water absorption and volume change. CONCLUSION It was concluded that the filler was directly responsible for the water absorption of the RTV material.
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Affiliation(s)
- M G Waters
- Department of Basic Dental Science, Cardiff Dental School, University of Wales College of Cardiff, UK
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Harrison M, Winter RW, McKenzie CG, Stewart JSW. Low dose endobronchial radiotherapy for recurrent carcinoma of the bronchus previously treated with radical radiotherapy. Eur J Cancer 1993. [DOI: 10.1016/0959-8049(93)91530-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
Polydimethylsiloxanes exhibit hydrophobic behaviour and poor wettability. These features impose some problems with the clinical performance of the material when used for the construction of intraoral and extraoral facial prostheses. Surface active agents were added to modify the surface energy of the polydimethylsiloxane and contact angle measurements were carried out to observe wetting characteristics. Five siloxane-alkene oxide block copolymers, one organosilicon quaternary ammonium chloride and an epoxyalkyl silane ester were used as surfactants. The best surfactant in terms of permanency and contact angle lowering achieved a value of 24 degrees when added at 10% level compared with 57 degrees for the unmodified silicone. The fairly high viscosity, combined with a comb-like structure, together with the high hydroxyl number of 75 provided the correct balance of permanence and wetting characteristics.
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Affiliation(s)
- G L Polyzois
- Department of Prosthodontics, School of Dentistry, University of Athens, Greece
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