1
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Mayoka G, Njoroge M, Okombo J, Gibhard L, Sanches-Vaz M, Fontinha D, Birkholtz LM, Reader J, van der Watt M, Coetzer TL, Lauterbach S, Churchyard A, Bezuidenhout B, Egan TJ, Yeates C, Wittlin S, Prudêncio M, Chibale K. Structure–Activity Relationship Studies and Plasmodium Life Cycle Profiling Identifies Pan-Active N-Aryl-3-trifluoromethyl Pyrido[1,2-a]benzimidazoles Which Are Efficacious in an in Vivo Mouse Model of Malaria. J Med Chem 2018; 62:1022-1035. [DOI: 10.1021/acs.jmedchem.8b01769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Godfrey Mayoka
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Mathew Njoroge
- Drug Discovery and Development Centre (H3D), Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Observatory, Cape Town 7925, South Africa
| | - John Okombo
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Liezl Gibhard
- Drug Discovery and Development Centre (H3D), Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Observatory, Cape Town 7925, South Africa
| | - Margarida Sanches-Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Diana Fontinha
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Janette Reader
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Mariëtte van der Watt
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Theresa L. Coetzer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Sonja Lauterbach
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Alisje Churchyard
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Belinda Bezuidenhout
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - Clive Yeates
- Inpharma
Consultancy, 6 Dudley Hill Close, Welwyn, Hertfordshire AL60QQ, U.K
| | - Sergio Wittlin
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
- South African Medical Research Council, Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
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2
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Singh K, Okombo J, Brunschwig C, Ndubi F, Barnard L, Wilkinson C, Njogu PM, Njoroge M, Laing L, Machado M, Prudêncio M, Reader J, Botha M, Nondaba S, Birkholtz LM, Lauterbach S, Churchyard A, Coetzer TL, Burrows JN, Yeates C, Denti P, Wiesner L, Egan TJ, Wittlin S, Chibale K. Antimalarial Pyrido[1,2-a]benzimidazoles: Lead Optimization, Parasite Life Cycle Stage Profile, Mechanistic Evaluation, Killing Kinetics, and in Vivo Oral Efficacy in a Mouse Model. J Med Chem 2017; 60:1432-1448. [DOI: 10.1021/acs.jmedchem.6b01641] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Kawaljit Singh
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry
and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - John Okombo
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Christel Brunschwig
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Ferdinand Ndubi
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Linley Barnard
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Chad Wilkinson
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Peter M. Njogu
- Department of Pharmaceutical Chemistry, University of Nairobi, P.O. Box 19676, Nairobi, 00202, Kenya
| | - Mathew Njoroge
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Lizahn Laing
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Marta Machado
- Instituto de Medicina Molecular, Faculdade
de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade
de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Janette Reader
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Mariette Botha
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Sindisiwe Nondaba
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Sonja Lauterbach
- Wits Research Institute for Malaria, Faculty
of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Alisje Churchyard
- Wits Research Institute for Malaria, Faculty
of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Theresa L. Coetzer
- Wits Research Institute for Malaria, Faculty
of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Jeremy N. Burrows
- Medicines for Malaria Venture, ICC, Route de Pré-Bois 20, P.O. Box 1826, 1215 Geneva, Switzerland
| | - Clive Yeates
- Inpharma Consultancy, 6 Dudley Hill Close, Welwyn, Hertfordshire AL60QQ, U.K
| | - Paolo Denti
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Lubbe Wiesner
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry
and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
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3
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Mital A, Murugesan D, Kaiser M, Yeates C, Gilbert IH. Discovery and optimisation studies of antimalarial phenotypic hits. Eur J Med Chem 2015; 103:530-8. [PMID: 26408453 PMCID: PMC4607724 DOI: 10.1016/j.ejmech.2015.08.044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/17/2015] [Accepted: 08/23/2015] [Indexed: 11/28/2022]
Abstract
There is an urgent need for the development of new antimalarial compounds. As a result of a phenotypic screen, several compounds with potent activity against the parasite Plasmodium falciparum were identified. Characterization of these compounds is discussed, along with approaches to optimise the physicochemical properties. The in vitro antimalarial activity of these compounds against P. falciparum K1 had EC50 values in the range of 0.09-29 μM, and generally good selectivity (typically >100-fold) compared to a mammalian cell line (L6). One example showed no significant activity against a rodent model of malaria, and more work is needed to optimise these compounds.
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Affiliation(s)
- Alka Mital
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee DD1 5EH, UK
| | - Dinakaran Murugesan
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee DD1 5EH, UK
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Postfach, Socinstrasse 57, 4002 Basel, Switzerland; University Basel, Petersplatz 1, 4003 Basel, Switzerland
| | | | - Ian H Gilbert
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee DD1 5EH, UK.
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4
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Murugesan D, Kaiser M, White KL, Norval S, Riley J, Wyatt PG, Charman SA, Read KD, Yeates C, Gilbert IH. Structure-activity relationship studies of pyrrolone antimalarial agents. ChemMedChem 2013; 8:1537-44. [PMID: 23918316 PMCID: PMC3963473 DOI: 10.1002/cmdc.201300177] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [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: 04/21/2013] [Indexed: 11/24/2022]
Abstract
Previously reported pyrrolones, such as TDR32570, exhibited potential as antimalarial agents; however, while these compounds have potent antimalarial activity, they suffer from poor aqueous solubility and metabolic instability. Here, further structure–activity relationship studies are described that aimed to solve the developability issues associated with this series of compounds. In particular, further modifications to the lead pyrrolone, involving replacement of a phenyl ring with a piperidine and removal of a potentially metabolically labile ester by a scaffold hop, gave rise to derivatives with improved in vitro antimalarial activities against Plasmodium falciparum K1, a chloroquine-and pyrimethamine-resistant parasite strain, with some derivatives exhibiting good selectivity for parasite over mammalian (L6) cells. Three representative compounds were selected for evaluation in a rodent model of malaria infection, and the best compound showed improved ability to decrease parasitaemia and a slight increase in survival.
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Affiliation(s)
- Dinakaran Murugesan
- Division of Biological Chemistry & Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dow St, Dundee DD1 5EH, UK
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5
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Murugesan D, Mital A, Kaiser M, Shackleford DM, Morizzi J, Katneni K, Campbell M, Hudson A, Charman SA, Yeates C, Gilbert IH. Discovery and structure-activity relationships of pyrrolone antimalarials. J Med Chem 2013; 56:2975-90. [PMID: 23517371 PMCID: PMC3624797 DOI: 10.1021/jm400009c] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [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: 11/29/2022]
Abstract
![]()
In
the pursuit of new antimalarial leads, a phenotypic screening
of various commercially sourced compound libraries was undertaken
by the World Health Organisation Programme for Research and Training
in Tropical Diseases (WHO-TDR). We report here the detailed characterization
of one of the hits from this process, TDR32750 (8a),
which showed potent activity against Plasmodium falciparum K1 (EC50 ∼ 9 nM), good selectivity (>2000-fold)
compared to a mammalian cell line (L6), and significant activity against
a rodent model of malaria when administered intraperitoneally. Structure–activity
relationship studies have indicated ways in which the molecule could
be optimized. This compound represents an exciting start point for
a drug discovery program for the development of a novel antimalarial.
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Affiliation(s)
- Dinakaran Murugesan
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee DD1 5EH, UK
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6
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Ndakala AJ, Gessner RK, Gitari PW, October N, White KL, Hudson A, Fakorede F, Shackleford DM, Kaiser M, Yeates C, Charman SA, Chibale K. Antimalarial pyrido[1,2-a]benzimidazoles. J Med Chem 2011; 54:4581-9. [PMID: 21644541 DOI: 10.1021/jm200227r] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel class of antimalarial pyrido[1,2-a]benzimidazoles were synthesized and evaluated for antiplasmodial activity and cytotoxicity following hits identified from screening commercially available compound collections. The most active of these, TDR86919 (4c), showed improved in vitro activity vs the drug-resistant K1 strain of Plasmodium falciparum relative to chloroquine (IC(50) = 0.047 μM v 0.17 μM); potency was retained against a range of drug-sensitive and drug-resistant strains, with negligible cytotoxicity against the mammalian (L-6) cell line (selectivity index of >600). 4c and several close analogues (as HCl or mesylate salts) showed significant efficacy in P. berghei infected mice following both intraperitoneal (ip) and oral (po) administration, with >90% inhibition of parasitemia, accompanied by an increase in the mean survival time (MSD). The pyrido[1,2-a]benzimidazoles appeared to be relatively slow acting in vivo compared to chloroquine, and metabolic stability of the alkylamino side chain was identified as a key issue in influencing in vivo activity.
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Affiliation(s)
- Albert J Ndakala
- Department of Chemistry, University of Cape Town, Rondebosch, South Africa
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7
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Yeates C, Blackall LL. Construction and analysis of a metagenomic library from an enhanced biological phosphorus removal biomass. Water Sci Technol 2006; 54:277-84. [PMID: 16898161 DOI: 10.2166/wst.2006.396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The enhanced biological phosphorus removal (EBPR) process is regularly used for the treatment of wastewater, but suffers from erratic performance. Successful EBPR relies on the growth of bacteria called polyphosphate-accumulating organisms (PAOs), which store phosphorus intracellularly as polyphosphate, thus removing it from wastewater. Metabolic models have been proposed which describe the measured chemical transformations, however genetic evidence is lacking to confirm these hypotheses. The aim of this research was to generate a metagenomic library from biomass enriched in PAOs as determined by phenotypic data and fluorescence in situ hybridisation (FISH) using probes specific for the only described PAO to date, "Candidatus Accumulibacter phosphatis". DNA extraction methods were optimised and two fosmid libraries were constructed which contained 93 million base pairs of metagenomic data. Initial screening of the library for 16S rRNA genes revealed fosmids originating from a range of nonpure-cultured wastewater bacteria. The metagenomic libraries constructed will provide the ability to link phylogenetic and metabolic data for bacteria involved in nutrient removal from wastewater.
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Affiliation(s)
- C Yeates
- Advanced Wastewater Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.
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8
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Yeates C. Icofungipen (PLIVA). Curr Opin Investig Drugs 2005; 6:838-44. [PMID: 16121691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Icofungipen is a cyclic beta-amino acid being development by PLIVA, under license from Bayer, for the potential oral treatment of fungal infection. As of September 2002, the first phase II efficacy study was underway.
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9
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Barton EN, Sargeant LA, Samuels D, Smith R, James J, Wilson R, Smith F, Falconer H, Yeates C, Smikle MF, Gilbert DT. A survey of chronic renal failure in Jamaica. W INDIAN MED J 2004; 53:81-4. [PMID: 15199716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The prevalence of chronic renal failure (CRF)/end stage renal disease and the accessibility of long term renal replacement therapy in Jamaica were evaluated. The study was conducted at six Jamaican healthcare facilities between July 1998 and December 1999 and included 605 patients with CRF. Men with CRF (57% of patients, mean age of 56.7 years) were significantly older than women (mean age 53.2 years). Hypertension was the most commonly associated medical condition (60.8% of patients) followed by diabetes mellitus (31.4% of patients). The estimated crude point prevalence of CRF in persons 20 years and over at the end of 1999 was 327 per million population. More than one-third of patients with CRF (39%) were receiving renal replacement therapy, the most common modality being haemodialysis, and only 1.8% of patients had received kidney transplantation. The prevalence of chronic renal failure was not increased in areas known to have high soil cadmium levels. Chronic renal failure is a significant public health problem in Jamaica and is placing an increasing financial burden on the healthcare sector.
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Affiliation(s)
- E N Barton
- Department of Medicine, Microbiology, University of the West Indies, Kingston Regional Hospital, Kingston, Jamaica, West Indies
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10
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Yeates C. DB-289 Immtech International. IDrugs 2003; 6:1086-93. [PMID: 14600842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
DB-289, an oral diamidoxime prodrug of DB-75 from the University of North Carolina, Georgia State University, Auburn University and Duke University, is being developed by Immtech International as a potential treatment for Pneumocystis carinii pneumonia (PCP), tuberculosis, trypanosomiasis and malaria.
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Affiliation(s)
- Clive Yeates
- 6 Dudley Hill Close, Welwyn, Herts, AL6 0QQ, UK.
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11
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Yeates C. Sitamaquine (GlaxoSmithKline/Walter Reed Army Institute). Curr Opin Investig Drugs 2002; 3:1446-52. [PMID: 12431016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Sitamaquine (WR-6026) is an orally active 8-aminoquinoline analog in development by the Walter Reed Army Institute, in collaboration with GlaxoSmithKline (formerly SmithKline Beecham), for the potential treatment of visceral leishmaniasis. Phase III trials for the treatment of visceral leishmaniasis had been initiated by March 2002, at which time GlaxoSmithKline hoped to file an MAA in 2003. By 1999, the compound had also undergone phase I trials in HIV-infected individuals for the treatment of Pneumocystis carinii infection. Preclinical studies have been conducted in primates and rodents for the potential treatment of Babesia microti infection.
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12
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Slater MJ, Baxter R, Bonser RW, Cockerill S, Gohil K, Parry N, Robinson E, Randall R, Yeates C, Snowden W, Walters A. Synthesis of N-alkyl substituted indolocarbazoles as potent inhibitors of human cytomegalovirus replication. Bioorg Med Chem Lett 2001; 11:1993-5. [PMID: 11454465 DOI: 10.1016/s0960-894x(01)00352-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [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: 10/18/2022]
Abstract
The synthesis and antiviral evaluation of unsymmetrical indolocarbazole derivatives of Arcyriaflavin A, substituted with a range of alkyl groups at the indole nitrogen, is described. Structure-activity relationships in this series against human cytomegalovirus (HCMV) replication in cell culture are reported. Compound 4b was identified as potent inhibitor of HCMV (IC(50)=19 nM), which retained activity against a range of HCMV strains including ganciclovir resistant isolates.
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Affiliation(s)
- M J Slater
- GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, SG1 2NY, Stevenage, UK.
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13
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Abstract
Ring-hydroxylating dioxygenases (RHDs) are of central importance to bacterial recycling of aromatic hydrocarbons, including anthropogenic pollutants. The database of presently characterized RHDs is biased towards those from organisms readily isolated on anthropogenic substrates. To investigate the extent to which RHDs from extant organisms reflect the natural diversity of these enzymes, we developed a polymerase chain reaction (PCR) method for retrieval of RHD gene fragments from environmental samples. Gene libraries from two contaminated and two pristine soil samples were constructed. None of the inferred peptides from clones examined were identical to previously described RHDs; however, all showed significant sequence homology and contained key catalytic residues. On the basis of sequence identity, the environmental clones clustered into six distinct groups, only one of which included known RHDs. One of the new sequence groupings was particularly widespread, being recovered from all soil samples tested. Comparison of inferred peptide sequences of the environmental clones and known RHDs showed the former to have greater sequence variation at sites thought to influence accessibility of the active site than that seen between currently known RHDs. We conclude that presently characterized RHDs do not adequately represent the diversity of function found in in situ forms.
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Affiliation(s)
- C Yeates
- Key Centre for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University, Sydney, NSW, Australia
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14
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Yeates C, Gillings MR, Davison AD, Altavilla N, Veal DA. Methods for microbial DNA extraction from soil for PCR amplification. Biol Proced Online 1998; 1:40-47. [PMID: 12734590 PMCID: PMC140122 DOI: 10.1251/bpo6] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [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: 02/26/1998] [Indexed: 11/24/2022] Open
Abstract
Amplification of DNA from soil is often inhibited by co-purified contaminants. A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types (1). DNA is also suitable for PCR amplification using various DNA targets. DNA was extracted from 100g of soil using direct lysis with glass beads and SDS followed by potassium acetate precipitation, polyethylene glycol precipitation, phenol extraction and isopropanol precipitation. This method was compared to other DNA extraction methods with regard to DNA purity and size.
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Affiliation(s)
- C Yeates
- Key Centre for Biodiversity and Bioresources, School of Biological Sciences. Macquarie University, Sydney, NSW 2109. Australia.
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15
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Abstract
The progesterone receptor (PR) mediates the actions of progesterone in the normal and malignant breast. PR is expressed as two proteins, PR B and PR A, which are expressed in normal progesterone target tissues and in breast cancers. A significant proportion of breast cancers contain, in addition, a smaller PR protein of molecular mass 78 kDa (PR78 kDa). The significance of PR78 kDa expression is unknown, and in particular, there are no data on whether PR78 kDa is able to bind ligand and therefore potentially exhibit transcriptional activity. If this smaller PR species exhibits similar differences in function as have been evidenced in vitro for PR A relative to PR B, it is possible that this PR species may be an important component in determination of progesterone response in breast cancer. The purpose of this study was to determine whether the PR78 kDa protein in breast tumors is able to bind ligand and to determine whether posttranscriptional mechanisms contribute to its formation in breast cancers. There was no evidence that PR78 kDa was derived from proteolytic activity of either PR B or PR A. Similarly, although exon-deleted PR transcripts were detected (which could, if translated, give rise to a PR protein similar in size to PR78 kDa), neither the abundance of such transcripts nor their relationship to levels of expressed PR78 kDa protein supported a role for exon deletion in formation of this truncated PR protein. PR78 kDa was not recognized by an antibody specific for PR B, indicating that, like PR A, it lacks the N-terminal portion of PR. PR78 kDa was able to bind the progestin ligand, indicating that it may have transcriptional activity. In summary, this study has shown that a truncated PR protein, found in breast cancers, is ligand-binding and seems to be derived from PR A, indicating that it may have a role in progesterone signaling, although a deeper understanding of its role, if any, in breast cancer remains to be established.
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Affiliation(s)
- C Yeates
- Westmead Institute for Cancer Research, University of Sydney, Westmead Hospital, NSW, Australia
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16
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Abstract
A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types. DNA was extracted from 100 g of soil using direct lysis with glass beads and sodium dodecyl sulphate (SDS) followed by polyethylene glycol precipitation, potassium acetate precipitation, phenol extraction and isopropanol precipitation. The crude extract could be used in PCR directed at high-copy number (bacterial small subunit rRNA) and single-copy (fungal beta-tubulin) genes.
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MESH Headings
- Base Sequence
- DNA/genetics
- DNA/isolation & purification
- DNA Primers/genetics
- DNA, Bacterial/genetics
- DNA, Bacterial/isolation & purification
- DNA, Fungal/genetics
- DNA, Fungal/isolation & purification
- DNA, Ribosomal/genetics
- DNA, Ribosomal/isolation & purification
- Evaluation Studies as Topic
- Genes, Fungal
- Polymerase Chain Reaction/methods
- RNA, Bacterial/genetics
- RNA, Ribosomal, 16S/genetics
- Soil Microbiology
- Tubulin/genetics
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Affiliation(s)
- C Yeates
- Key Centre for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University, Sydney, Australia.
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Abstract
The human progesterone receptor (PR) is a ligand-activated nuclear transcription factor which mediates progesterone action in target tissues. Two PR proteins, PR A (81-83 kDa) and PR B (116-120 kDa), have been described and different physiological activities ascribed to each on the basis of in vitro studies, suggesting that their ratio of expression may control progesterone responsiveness in target cells. Presence of PR in breast tumors is an important indicator of likely responsiveness to endocrine agents. However, the relative expression of PR A and B in breast cancer has not been described and its clinical significance has not been addressed. We have examined the expression of PR A and B in PR-positive breast tumors and found that while in most tumors PR A and B were expressed in similar amounts there was a broad overall distribution of PR A:B ratio which deviated significantly from a normal log distribution with tumors containing a PR A:B ration greater than 4 being over-represented in the group. Linear regression analysis revealed that high PR A:B ratios, in general, derived from a low concentration of PR B rather than high expression of PR A. PR A:B protein ratios were not correlated with the age of the patient or with total PR concentration. A third PR protein band (PR 78 kDa) was detected which comprised greater than 20% of total PR protein in a quarter of the tumor samples examined. The characteristics of tumors containing PR 78 kDa were not different from the overall group. In summary, in PR-positive breast tumors the ratio of expression of PR A and B proteins is close to unity as is seen in a number of other progestin target tissues. However, a significant proportion of tumors expressed very low levels of PR B and a consequently high PR A:B ration. Although the clinical consequence of this observation is not known, the in vitro findings that PR A may act as a repressor for PR B suggests that tumors containing primarily PR A may identify a subset of patients with low or aberrant response to endocrine agents.
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Affiliation(s)
- J D Graham
- Department of Medical Oncology, University of Sydney Westmead Hospital, NSW, Australia
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Graham JD, Yeates C, Balleine RL, Harvey SS, Milliken JS, Bilous AM, Clarke CL. Characterization of progesterone receptor A and B expression in human breast cancer. Cancer Res 1995; 55:5063-8. [PMID: 7585552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The human progesterone receptor (PR) is a ligand-activated nuclear transcription factor that mediates progesterone action in target tissues. Two PR proteins, PR-A (M(r) 81,000-83,000) and PR-B (M(r) 116,000-120,000), have been described and different physiological activities ascribed to each on the basis of in vitro studies, suggesting that their ratio of expression may control progesterone responsiveness in target cells. Presence of PR in breast tumors is an important indicator of likely responsiveness to endocrine agents. However, the relative expression of PR-A and B in breast cancer has not been described, and its clinical significance has not been addressed. Expression of PR-A and B was measured by immunoblot analysis of 202 PR-positive human breast tumor cytosols. The ratio of expression of the two PR proteins (PR-A/B) ranged from 0.04 to 179.3. The median PR-A/B ratio was 1.26, and 61.4% of samples had PR-A/B ratios between 0 and 2. PR-A/B ratios deviated significantly from a normal log distribution; tumors containing a PR-A/B ratio greater than 4 were overrepresented in the group. Linear regression analysis revealed that high PR-A/B ratios, in general, derived from a low concentration of PR-B rather than high expression of PR-A. PR-A/B protein ratios were not correlated with the age of the patient or with total PR concentration. A third PR protein band (PR78kDa) was detected in a number of samples and comprised greater than 20% of total PR protein in 52 (25.7%) of the 202 tumor samples examined. The range or frequency distribution of PR-A/B ratios in samples containing PR78kDa was not different to the overall group. In summary, in PR-positive breast tumors, the ratio of expression of PR-A and B proteins is close to unity, as is seen in a number of other progestin target tissues. However, a significant proportion of tumors expressed very low levels of PR-B and a consequently high PR-A/B ratio. Although the clinical consequence of this observation is not known, the in vitro findings that PR-A may act as a repressor of PR-B suggest that tumors containing primarily PR-A may identify a subset of patients with low or aberrant response to endocrine agents.
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Affiliation(s)
- J D Graham
- Department of Medical Oncology, University of Sydney, Australia
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Kocieński PJ, Street SDA, Yeates C, Cambell SF. The 3,4-dihydro-2H-pyran approach to (+)-milbemycin β3. Part 2. An improved synthesis of (2R,4S,6S,8R,9S)-2-[(5R)-(2E)-3-methyl-5-formyl-hex-2-en-1-yl]-8,9-dimethyl-4-(dimethyl-t-butylsilyloxy)-1,7-dioxaspiro[5.5]undecane. ACTA ACUST UNITED AC 1987. [DOI: 10.1039/p19870002189] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wadman S, Whitby R, Yeates C, Kocienski P, Cooper K. An efficient and stereoselective synthesisi of homoallylic alcohols via nickel-catalysed coupling of 5-alkyl-2,3-dihydrofurans with Grignard reagents. ACTA ACUST UNITED AC 1987. [DOI: 10.1039/c39870000241] [Citation(s) in RCA: 34] [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] [Indexed: 11/21/2022]
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Kocieński PJ, Yeates C, Street SDA, Campbell SF. The 3,4-dihydro-2H-pyran approach to (+)-milbemycin β3. Part 1. An alternative synthesis of (2S,4S,6R,8R,9S)-2-formylmethyl-4-(dimethyl-t-butylsilyloxy)-8,9-dimethyl-1,7-dioxaspiro[5.5]undecane. ACTA ACUST UNITED AC 1987. [DOI: 10.1039/p19870002183] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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