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Aguilera E, Sánchez C, Cruces ME, Dávila B, Minini L, Mosquillo F, Pérez-Díaz L, Serna E, Torres S, Schini A, Sanabria L, Vera de Bilbao NI, Yaluff G, Zolessi FR, Ceilas LF, Cerecetto H, Alvarez G. Preclinical Studies and Drug Combination of Low-Cost Molecules for Chagas Disease. Pharmaceuticals (Basel) 2022; 16:ph16010020. [PMID: 36678516 PMCID: PMC9863266 DOI: 10.3390/ph16010020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 12/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Chagas disease is caused by the protozoan Trypanosoma cruzi (T. cruzi). It remains the major parasitic disease in Latin America and is spreading worldwide, affecting over 10 million people. Hundreds of new compounds with trypanosomicidal action have been identified from different sources such as synthetic or natural molecules, but they have been deficient in several stages of drug development (toxicology, scaling-up, and pharmacokinetics). Previously, we described a series of compounds with simple structures, low cost, and environmentally friendly production with potent trypanosomicidal activity in vitro and in vivo. These molecules are from three different families: thiazolidenehydrazines, diarylideneketones, and steroids. From this collection, we explored their capacity to inhibit the triosephosphate isomerase and cruzipain of T. cruzi. Then, the mechanism of action was explored using NMR metabolomics and computational molecular dynamics. Moreover, the mechanism of death was studied by flow cytometry. Consequently, five compounds, 314, 793, 1018, 1019, and 1260, were pre-clinically studied and their pharmacologic profiles indicated low unspecific toxicity. Interestingly, synergetic effects of diarylideneketones 793 plus 1018 and 793 plus 1019 were evidenced in vitro and in vivo. In vivo, the combination of compounds 793 plus 1018 induced a reduction of more than 90% of the peak of parasitemia in the acute murine model of Chagas disease.
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Affiliation(s)
- Elena Aguilera
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - Carina Sánchez
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - María Eugenia Cruces
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - Belén Dávila
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - Lucía Minini
- Laboratorio de Química Teórica y Computacional, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - Florencia Mosquillo
- Laboratorio de Interacciones Moleculares, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - Leticia Pérez-Díaz
- Laboratorio de Interacciones Moleculares, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
| | - Elva Serna
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo 2169, Paraguay
| | - Susana Torres
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo 2169, Paraguay
| | - Alicia Schini
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo 2169, Paraguay
| | - Luis Sanabria
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo 2169, Paraguay
| | - Ninfa I. Vera de Bilbao
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo 2169, Paraguay
| | - Gloria Yaluff
- Departamento de Medicina Tropical, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, San Lorenzo 2169, Paraguay
| | - Flavio R. Zolessi
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República and Institut Pasteur de Montevideo, Montevideo 11400, Uruguay
| | | | - Hugo Cerecetto
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay
- Correspondence: (H.C.); (G.A.)
| | - Guzmán Alvarez
- Laboratorio de Moléculas Bioactivas, Departamento de Ciencias Biológicas, CENUR Litoral Norte, Universidad de la República, Rute 3 km 363, Paysandú 60000, Uruguay
- Correspondence: (H.C.); (G.A.)
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Drug associations as alternative and complementary therapy for neglected tropical diseases. Acta Trop 2022; 225:106210. [PMID: 34687644 DOI: 10.1016/j.actatropica.2021.106210] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/02/2021] [Accepted: 10/15/2021] [Indexed: 12/23/2022]
Abstract
The present paper aims to establish different treatments for neglected tropical disease by a survey on drug conjugations and possible fixed-dose combinations (FDC) used to obtain alternative, safer and more effective treatments. The source databases used were Science Direct and PubMed/Medline, in the intervals between 2015 and 2021 with the drugs key-words or diseases, like "schistosomiasis", "praziquantel", "malaria", "artesunate", "Chagas' disease", "benznidazole", "filariasis", diethylcarbamazine", "ivermectin", " albendazole". 118 works were the object of intense analysis, other articles and documents were used to increase the quality of the studies, such as consensuses for harmonizing therapeutics and historical articles. As a result, an effective NTD control can be achieved when different public health approaches are combined with interventions guided by the epidemiology of each location and the availability of appropriate measures to detect, prevent and control disease. It was also possible to verify that the FDCs promote a simplification of the therapeutic regimen, which promotes better patient compliance and enables a reduction in the development of parasitic resistance, requiring further studies aimed at resistant strains, since the combined APIs usually act by different mechanisms or at different target sites. In addition to eliminating the process of developing a new drug based on the identification and validation of active compounds, which is a complex, long process and requires a strong long-term investment, other advantages that FDCs have are related to productive gain and gain from the industrial plant, which can favor and encourage the R&D of new FDCs not only for NTDs but also for other diseases that require the use of more than one drug.
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Bar Routaray C, Bhor R, Bai S, Kadam NS, Jagtap S, Doshi PJ, Sundar S, Sawant S, Kulkarni MJ, Pai K. SWATH-MS based quantitative proteomics analysis to evaluate the antileishmanial effect of Commiphora wightii- Guggul and Amphotericin B on a clinical isolate of Leishmania donovani. J Proteomics 2020; 223:103800. [DOI: 10.1016/j.jprot.2020.103800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 04/25/2020] [Accepted: 04/27/2020] [Indexed: 12/15/2022]
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Aguilera E, Alvarez G, Cerecetto H, González M. Polypharmacology in the Treatment of Chagas Disease. Curr Med Chem 2019; 26:4476-4489. [PMID: 29637852 DOI: 10.2174/0929867325666180410101728] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 03/28/2018] [Accepted: 04/28/2018] [Indexed: 01/06/2023]
Abstract
The current treatment of Chagas disease is based on monopharmacology where the used drugs have limited efficacy and severe side effects. In order to overcome these limitations, some tools have been described including the development or isolation of new drugs, drug repositioning, and polypharmacology. Here, we review the polypharmacology strategy where compounds belonging to different structural chemotypes were combined in order to affect different biochemical pathways of T. cruzi parasite. Therefore ergosterol biosynthesis inhibitors, anti-inflammatory agents, cardiac dysfunction drugs, trypanothione reductase inhibitors, vitamins, between others, were combined looking for new anti-Chagas treatment. Natural products were also used in the application of this strategy.
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Affiliation(s)
- Elena Aguilera
- Grupo de Quimica Medicinal, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Guzmán Alvarez
- Grupo de Quimica Medicinal, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.,Laboratorio de Moléculas Bioactivas, Centro Universitario Regional Litoral Norte, Universidad de la República, Paysandú, Uruguay
| | - Hugo Cerecetto
- Grupo de Quimica Medicinal, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.,Area de Radiofarmacia, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la Republica, Montevideo, Uruguay
| | - Mercedes González
- Grupo de Quimica Medicinal, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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Synergic Effect of Allopurinol in Combination with Nitroheterocyclic Compounds against Trypanosoma cruzi. Antimicrob Agents Chemother 2019; 63:AAC.02264-18. [PMID: 30962342 PMCID: PMC6535576 DOI: 10.1128/aac.02264-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/24/2019] [Indexed: 11/20/2022] Open
Abstract
Combination therapy has gained attention as a possible strategy for overcoming the limitations of the present therapeutic arsenal for Chagas disease. The aim of this study was to evaluate the effect of allopurinol in association with nitroheterocyclic compounds on infection with the Y strain of Trypanosoma cruzi The in vitro effect of allopurinol plus benznidazole or nifurtimox on intracellular amastigotes in infected H9c2 cells was assessed in a 72-h assay. The interactions were classified as synergic for both allopurinol-nifurtimox (sums of fractional inhibitory concentrations [∑FICs] = 0.49 ± 0.08) and allopurinol-benznidazole (∑FICs = 0.48 ± 0.09). In the next step, infected Swiss mice were treated with allopurinol at 30, 60, and 90 mg/kg of body weight and with benznidazole at 25, 50, and 75 mg/kg in monotherapy and in combination at the same doses; as a reference treatment, another group of animals received benznidazole at 100 mg/kg. Allopurinol in monotherapy led to a smaller or nil effect in the reduction of parasite load and mortality rate. Treatment with benznidazole at suboptimal doses induced a transient suppression of parasitaemia with subsequent relapse in all animals treated with 25 and 50 mg/kg and in 80% of those that received 75 mg/kg. Administration of the drugs in combination significantly increased the cure rate to 60 to 100% among mice treated with benznidazole at 75 mg/kg plus 30, 60, or 90 mg/kg of allopurinol. These results show a positive interaction between allopurinol and benznidazole, and since both drugs are commercially available, their use in combination may be considered for the assessment in the treatment of Chagas disease patients.
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Zakai HA, Zimmo SK. Effects of itraconazole and terbinafine onLeishmania majorlesions in BALB/c mice. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.2000.11813603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Skinner-Adams TS, Sumanadasa SD, Fisher GM, Davis RA, Doolan DL, Andrews KT. Defining the targets of antiparasitic compounds. Drug Discov Today 2016; 21:725-39. [DOI: 10.1016/j.drudis.2016.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/04/2015] [Accepted: 01/07/2016] [Indexed: 10/22/2022]
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Assíria Fontes Martins T, de Figueiredo Diniz L, Mazzeti AL, da Silva do Nascimento ÁF, Caldas S, Caldas IS, de Andrade IM, Ribeiro I, Bahia MT. Benznidazole/Itraconazole Combination Treatment Enhances Anti-Trypanosoma cruzi Activity in Experimental Chagas Disease. PLoS One 2015; 10:e0128707. [PMID: 26076455 PMCID: PMC4468053 DOI: 10.1371/journal.pone.0128707] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 04/29/2015] [Indexed: 11/29/2022] Open
Abstract
The nitroheterocyclic drugs nifurtimox and benznidazole are first-line drugs available to treat Chagas disease; however, they have limitations, including long treatment courses and toxicity. Strategies to overcome these limitations include the identification of new drugs with specific target profiles, re-dosing regimens for the current drugs, drug repositioning and combination therapy. In this work, we evaluated combination therapy as an approach for optimization of the current therapeutic regimen for Chagas disease. The curative action of benznidazole/itraconazole combinations was explored in an established infection of the mice model with the T. cruzi Y strain. The activities of the benznidazole/itraconazole combinations were compared with the results from those receiving the same dosage of each individual drug. The administration of benznidazole/itraconazole in combination eliminated parasites from the blood more efficiently than each drug alone. Here, there was a significant reduction of the number of treatment days (number of doses) necessary to induce parasitemia suppression with the benznidazole/itraconazole combination, as compared to each compound administered alone. These results clearly indicate the enhanced effects of these drugs in combination, particularly at the dose of 75 mg/kg, as the effects observed with the drug combinations were four times more effective than those of each drug used alone. Moreover, benznidazole/itraconazole treatment was shown to prevent or decrease the typical lesions associated with chronic experimental Chagas disease, as illustrated by similar levels of inflammatory cells and fibrosis in the cardiac muscle tissue of healthy and treated mice. These results emphasize the importance of exploring the potential of combination treatments with currently available compounds to specifically treat Chagas disease.
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Affiliation(s)
- Tassiane Assíria Fontes Martins
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
| | - Lívia de Figueiredo Diniz
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
- Departamento de Patologia e Parasitologia, Instituto de Ciências Biomédicas, Universidade Federal de Alfenas, Alfenas, Minas Gerais, Brazil
| | - Ana Lia Mazzeti
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
| | - Álvaro Fernando da Silva do Nascimento
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
| | - Sérgio Caldas
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
- Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | - Ivo Santana Caldas
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
- Departamento de Patologia e Parasitologia, Instituto de Ciências Biomédicas, Universidade Federal de Alfenas, Alfenas, Minas Gerais, Brazil
| | - Isabel Mayer de Andrade
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
| | - Isabela Ribeiro
- Drugs for Neglected Disease initiative (DNDi), 1202 Geneva, Switzerland
| | - Maria Terezinha Bahia
- Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Universitário, Morro do Cruzeiro, Ouro Preto, Minas Gerais, Brazil
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Fügi MA, Kaiser M, Tanner M, Schneiter R, Mäser P, Guan XL. Match-making for posaconazole through systems thinking. Trends Parasitol 2014; 31:46-51. [PMID: 25486978 DOI: 10.1016/j.pt.2014.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/07/2014] [Accepted: 11/11/2014] [Indexed: 12/20/2022]
Abstract
Currently available drugs for Chagas' disease are limited by toxicity and low efficacy in the chronic stage. Posaconazole, the most advanced new anti-chagasic drug candidate, did not fully confirm its initial potential in a Phase II clinical trial for chronic Chagas' disease. Given that posaconazole is highly active against Trypanosoma cruzi in vitro, and was very well tolerated in clinical trials, it should not be abandoned. Rather, a combination therapy may provide a highly promising outlook. Systems-scale approaches facilitate the hunt for a combination partner for posaconazole, which acts by blocking sterol biosynthesis. Mounting evidence suggests the functional interactions between sterols and sphingolipids in vivo. Here, we propose combining sterol and sphingolipid biosynthesis inhibitors to advance drug development in Chagas' disease.
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Affiliation(s)
- Matthias A Fügi
- Swiss Tropical and Public Health Institute, CH-4051 Basel, Switzerland; University of Basel, CH-4000 Basel, Switzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, CH-4051 Basel, Switzerland; University of Basel, CH-4000 Basel, Switzerland
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, CH-4051 Basel, Switzerland; University of Basel, CH-4000 Basel, Switzerland
| | | | - Pascal Mäser
- Swiss Tropical and Public Health Institute, CH-4051 Basel, Switzerland; University of Basel, CH-4000 Basel, Switzerland
| | - Xue Li Guan
- Swiss Tropical and Public Health Institute, CH-4051 Basel, Switzerland; University of Basel, CH-4000 Basel, Switzerland.
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Haubrich BA, Singha UK, Miller MB, Nes CR, Anyatonwu H, Lecordier L, Patkar P, Leaver DJ, Villalta F, Vanhollebeke B, Chaudhuri M, Nes WD. Discovery of an ergosterol-signaling factor that regulates Trypanosoma brucei growth. J Lipid Res 2014; 56:331-41. [PMID: 25424002 DOI: 10.1194/jlr.m054643] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ergosterol biosynthesis and homeostasis in the parasitic protozoan Trypanosoma brucei was analyzed by RNAi silencing and inhibition of sterol C24β-methyltransferase (TbSMT) and sterol 14α-demethylase [TbSDM (TbCYP51)] to explore the functions of sterols in T. brucei growth. Inhibition of the amount or activity of these enzymes depletes ergosterol from cells at <6 fg/cell for procyclic form (PCF) cells or <0.01 fg/cell for bloodstream form (BSF) cells and reduces infectivity in a mouse model of infection. Silencing of TbSMT expression by RNAi in PCF or BSF in combination with 25-azalanosterol (AZA) inhibited parasite growth and this inhibition was restored completely by adding synergistic cholesterol (7.8 μM from lipid-depleted media) with small amounts of ergosterol (1.2 μM) to the medium. These observations are consistent with the proposed requirement for ergosterol as a signaling factor to spark cell proliferation while imported cholesterol or the endogenously formed cholesta-5,7,24-trienol act as bulk membrane components. To test the potential chemotherapeutic importance of disrupting ergosterol biosynthesis using pairs of mechanism-based inhibitors that block two enzymes in the post-squalene segment, parasites were treated with AZA and itraconazole at 1 μM each (ED50 values) resulting in parasite death. Taken together, our results demonstrate that the ergosterol pathway is a prime drug target for intervention in T. brucei infection.
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Affiliation(s)
- Brad A Haubrich
- Center for Chemical Biology and Department of Chemistry and Biochemistry Texas Tech University, Lubbock, TX 79409
| | - Ujjal K Singha
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208
| | - Matthew B Miller
- Center for Chemical Biology and Department of Chemistry and Biochemistry Texas Tech University, Lubbock, TX 79409
| | - Craigen R Nes
- Center for Chemical Biology and Department of Chemistry and Biochemistry Texas Tech University, Lubbock, TX 79409
| | - Hosanna Anyatonwu
- Center for Chemical Biology and Department of Chemistry and Biochemistry Texas Tech University, Lubbock, TX 79409
| | - Laurence Lecordier
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, B6041 Gosselies, Belgium
| | - Presheet Patkar
- Center for Chemical Biology and Department of Chemistry and Biochemistry Texas Tech University, Lubbock, TX 79409
| | - David J Leaver
- Center for Chemical Biology and Department of Chemistry and Biochemistry Texas Tech University, Lubbock, TX 79409 Institute of Chemistry and Biomedical Sciences, Nanjing University, Nanjing 210023, People's Republic of China
| | - Fernando Villalta
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208
| | - Benoit Vanhollebeke
- Laboratoire de Parasitologie Moléculaire, IBMM, Université Libre de Bruxelles, B6041 Gosselies, Belgium
| | - Minu Chaudhuri
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208
| | - W David Nes
- Center for Chemical Biology and Department of Chemistry and Biochemistry Texas Tech University, Lubbock, TX 79409
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Bahia MT, Diniz LDF, Mosqueira VCF. Therapeutical approaches under investigation for treatment of Chagas disease. Expert Opin Investig Drugs 2014; 23:1225-37. [DOI: 10.1517/13543784.2014.922952] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Molina I, Gómez i Prat J, Salvador F, Treviño B, Sulleiro E, Serre N, Pou D, Roure S, Cabezos J, Valerio L, Blanco-Grau A, Sánchez-Montalvá A, Vidal X, Pahissa A. Randomized trial of posaconazole and benznidazole for chronic Chagas' disease. N Engl J Med 2014; 370:1899-908. [PMID: 24827034 DOI: 10.1056/nejmoa1313122] [Citation(s) in RCA: 432] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Current therapeutic options for Chagas' disease are limited to benznidazole and nifurtimox, which have been associated with low cure rates in the chronic stage of the disease and which have considerable toxicity. Posaconazole has shown trypanocidal activity in murine models. METHODS We performed a prospective, randomized clinical trial to assess the efficacy and safety of posaconazole as compared with the efficacy and safety of benznidazole in adults with chronic Trypanosoma cruzi infection. We randomly assigned patients to receive posaconazole at a dose of 400 mg twice daily (high-dose posaconazole), posaconazole at a dose of 100 mg twice daily (low-dose posaconazole), or benznidazole at a dose of 150 mg twice daily; all the study drugs were administered for 60 days. We assessed antiparasitic activity by testing for the presence of T. cruzi DNA, using real-time polymerase-chain-reaction (rt-PCR) assays, during the treatment period and 10 months after the end of treatment. Posaconazole absorption was assessed on day 14. RESULTS The intention-to-treat population included 78 patients. During the treatment period, all the patients tested negative for T. cruzi DNA on rt-PCR assay beyond day 14, except for 2 patients in the low-dose posaconazole group who tested positive on day 60. During the follow-up period, in the intention-to-treat analysis, 92% of the patients receiving low-dose posaconazole and 81% receiving high-dose posaconazole, as compared with 38% receiving benznidazole, tested positive for T. cruzi DNA on rt-PCR assay (P<0.01 for the comparison of the benznidazole group with either posaconazole group); in the per-protocol analysis, 90% of the patients receiving low-dose posaconazole and 80% of those receiving high-dose posaconazole, as compared with 6% receiving benznidazole, tested positive on rt-PCR assay (P<0.001 for the comparison of the benznidazole group with either posaconazole group). In the benznidazole group, treatment was discontinued in 5 patients because of severe cutaneous reactions; in the posaconazole groups, 4 patients had aminotransferase levels that were more than 3 times the upper limit of the normal range, but there were no discontinuations of treatment. CONCLUSIONS Posaconazole showed antitrypanosomal activity in patients with chronic Chagas' disease. However, significantly more patients in the posaconazole groups than in the benznidazole group had treatment failure during follow-up. (Funded by the Ministry of Health, Spain; CHAGASAZOL ClinicalTrials.gov number, NCT01162967.).
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Affiliation(s)
- Israel Molina
- From the Infectious Disease Department (I.M., F.S., A.S.-M., A.P.), Microbiology Department (E.S.), the Drug Monitoring Unit, Clinical Laboratory (A.B.-G.), and the Clinical Pharmacology Service (X.V.), Vall d'Hebron Teaching Hospital, Special Program for Infectious Diseases, Vall d'Hebron Drassanes (J.G.P., B.T., N.S., D.P., J.C.), International Health Program of the Catalan Institute of Health (PROSICS) Barcelona (I.M., J.G.P., F.S., B.T., E.S., N.S., D.P., J.C., A.S.-M., A.P.), International Health Unit Metropolitana Nord, Infectious Disease Unit, Internal Medicine Department, Germans Trias i Pujol Teaching Hospital (S.R.), and International Health Unit Metropolitana Nord (L.V.), PROSICS Metropolitana Nord, and the Department of Pharmacology, Therapeutics, and Toxicology, Universitat Autònoma de Barcelona, and Fundació Institut Català de Farmacologia, WHO Collaborating Center for Research and Training in Pharmacoepidemiology (X.V.) - all in Barcelona
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Shang N, Li Q, Ko TP, Chan HC, Li J, Zheng Y, Huang CH, Ren F, Chen CC, Zhu Z, Galizzi M, Li ZH, Rodrigues-Poveda CA, Gonzalez-Pacanowska D, Veiga-Santos P, de Carvalho TMU, de Souza W, Urbina JA, Wang AHJ, Docampo R, Li K, Liu YL, Oldfield E, Guo RT. Squalene synthase as a target for Chagas disease therapeutics. PLoS Pathog 2014; 10:e1004114. [PMID: 24789335 PMCID: PMC4006925 DOI: 10.1371/journal.ppat.1004114] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/28/2014] [Indexed: 12/20/2022] Open
Abstract
Trypanosomatid parasites are the causative agents of many neglected tropical diseases and there is currently considerable interest in targeting endogenous sterol biosynthesis in these organisms as a route to the development of novel anti-infective drugs. Here, we report the first x-ray crystallographic structures of the enzyme squalene synthase (SQS) from a trypanosomatid parasite, Trypanosoma cruzi, the causative agent of Chagas disease. We obtained five structures of T. cruzi SQS and eight structures of human SQS with four classes of inhibitors: the substrate-analog S-thiolo-farnesyl diphosphate, the quinuclidines E5700 and ER119884, several lipophilic bisphosphonates, and the thiocyanate WC-9, with the structures of the two very potent quinuclidines suggesting strategies for selective inhibitor development. We also show that the lipophilic bisphosphonates have low nM activity against T. cruzi and inhibit endogenous sterol biosynthesis and that E5700 acts synergistically with the azole drug, posaconazole. The determination of the structures of trypanosomatid and human SQS enzymes with a diverse set of inhibitors active in cells provides insights into SQS inhibition, of interest in the context of the development of drugs against Chagas disease. Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects eight million individuals, primarily in Latin America. Currently there is no cure for chronic T. cruzi infections. Unlike humans, this parasite use a variety of sterols (e.g. ergosterol, 24-ethyl-cholesta-5,7,22-trien-3 beta ol, and its 22-dihydro analogs), rather than cholesterol in their cell membranes, so inhibiting endogenous sterol biosynthesis is an important therapeutic target. Here, we report the first structure of the parasite's squalene synthase, which catalyzes the first committed step in sterol biosynthesis, as well as the structures of a broad range of squalene synthase inhibitors active against the clinically relevant intracellular stages, opening the way to new approaches to treating this neglected tropical disease.
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Affiliation(s)
- Na Shang
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Qian Li
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tzu-Ping Ko
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsiu-Chien Chan
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Jikun Li
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Yingying Zheng
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Chun-Hsiang Huang
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Feifei Ren
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Chun-Chi Chen
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Zhen Zhu
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Melina Galizzi
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Zhu-Hong Li
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Carlos A. Rodrigues-Poveda
- Instituto de Parasitología y Biomedicina “Lopez-Neyra”, Consejo Superior de Investigaciones Cientificas, Granada, Spain
| | - Dolores Gonzalez-Pacanowska
- Instituto de Parasitología y Biomedicina “Lopez-Neyra”, Consejo Superior de Investigaciones Cientificas, Granada, Spain
| | - Phercyles Veiga-Santos
- Laboratório de Ultraestrutura Celular Hertha Meyer, CCS, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
- Diretoria de Programa, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial–INMETRO, Duque de Caxias, Rio de Janeiro, Brazil
| | - Tecia Maria Ulisses de Carvalho
- Laboratório de Ultraestrutura Celular Hertha Meyer, CCS, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
- Diretoria de Programa, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial–INMETRO, Duque de Caxias, Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, CCS, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
- Diretoria de Programa, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial–INMETRO, Duque de Caxias, Rio de Janeiro, Brazil
| | - Julio A. Urbina
- Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela
| | | | - Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Kai Li
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Yi-Liang Liu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Eric Oldfield
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail: (EO); (RTG)
| | - Rey-Ting Guo
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- * E-mail: (EO); (RTG)
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Rodrigues JHDS, Ueda-Nakamura T, Corrêa AG, Sangi DP, Nakamura CV. A quinoxaline derivative as a potent chemotherapeutic agent, alone or in combination with benznidazole, against Trypanosoma cruzi. PLoS One 2014; 9:e85706. [PMID: 24465654 PMCID: PMC3894994 DOI: 10.1371/journal.pone.0085706] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 12/02/2013] [Indexed: 11/18/2022] Open
Abstract
Background Chagas’ disease is a condition caused by the protozoan Trypanosoma cruzi that affects millions of people, mainly in Latin America where it is considered endemic. The chemotherapy for Chagas disease remains a problem; the standard treatment currently relies on a single drug, benznidazole, which unfortunately induces several side effects and it is not successful in the cure of most of the chronic patients. In order to improve the drug armamentarium against Chagas’ disease, in the present study we describe the synthesis of the compound 3-chloro-7-methoxy-2-(methylsulfonyl) quinoxaline (quinoxaline 4) and its activity, alone or in combination with benznidazole, against Trypanosoma cruzi in vitro. Methodology/Principal Findings Quinoxaline 4 was found to be strongly active against Trypanosoma cruzi Y strain and more effective against the proliferative forms. The cytotoxicity against LLCMK2 cells provided selective indices above one for all of the parasite forms. The drug induced very low hemolysis, but its anti-protozoan activity was partially inhibited when mouse blood was added in the experiment against trypomastigotes, an effect that was specifically related to blood cells. A synergistic effect between quinoxaline 4 and benznidazole was observed against epimastigotes and trypomastigotes, accompanied by an antagonistic interaction against LLCMK2 cells. Quinoxaline 4 induced several ultrastructural alterations, including formations of vesicular bodies, profiles of reticulum endoplasmic surrounding organelles and disorganization of Golgi complex. These alterations were also companied by cell volume reduction and maintenance of cell membrane integrity of treated-parasites. Conclusion/Significance Our results demonstrated that quinoxaline 4, alone or in combination with benznidazole, has promising effects against all the main forms of T. cruzi. The compound at low concentrations induced several ultrastructural alterations and led the parasite to an autophagic-like cell death. Taken together these results may support the further development of a combination therapy as an alternative more effective in Chagas’ disease treatment.
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Affiliation(s)
- Jean Henrique da Silva Rodrigues
- Programa de Pós-Graduação em Ciências Biológicas – Biologia Celular e Molecular, Universidade Estadual de Maringá, Maringá, Paraná, Brazil
| | - Tânia Ueda-Nakamura
- Departamento de Ciências Básicas da Saúde - Laboratório de Inovação Tecnológica no Desenvolvimento de Fármacos e Cosméticos, Universidade Estadual de Maringá, Maringá, Paraná, Brazil
| | - Arlene Gonçalves Corrêa
- Departamento de Química - Laboratório de Síntese de Produtos Naturais, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Diego Pereira Sangi
- Departamento de Química - Laboratório de Síntese de Produtos Naturais, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Celso Vataru Nakamura
- Departamento de Ciências Básicas da Saúde - Laboratório de Inovação Tecnológica no Desenvolvimento de Fármacos e Cosméticos, Universidade Estadual de Maringá, Maringá, Paraná, Brazil
- * E-mail:
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Guedes PMM, Silva GK, Gutierrez FRS, Silva JS. Current status of Chagas disease chemotherapy. Expert Rev Anti Infect Ther 2014; 9:609-20. [DOI: 10.1586/eri.11.31] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Diniz LDF, Urbina JA, de Andrade IM, Mazzeti AL, Martins TAF, Caldas IS, Talvani A, Ribeiro I, Bahia MT. Benznidazole and posaconazole in experimental Chagas disease: positive interaction in concomitant and sequential treatments. PLoS Negl Trop Dis 2013; 7:e2367. [PMID: 23967360 PMCID: PMC3744424 DOI: 10.1371/journal.pntd.0002367] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 07/02/2013] [Indexed: 01/12/2023] Open
Abstract
Background Current chemotherapy for Chagas disease is unsatisfactory due to its limited efficacy, particularly in the chronic phase, with frequent side effects that can lead to treatment discontinuation. Combined therapy is envisioned as an ideal approach since it may improve treatment efficacy whilst decreasing toxicity and the likelihood of resistance development. We evaluated the efficacy of posaconazole in combination with benznidazole on Trypanosoma cruzi infection in vivo. Methods and Findings Benznidazole and posaconazole were administered individually or in combination in an experimental acute murine infection model. Using a rapid treatment protocol for 7 days, the combined treatments were more efficacious in reducing parasitemia levels than the drugs given alone, with the effects most evident in combinations of sub-optimal doses of the drugs. Subsequently, the curative action of these drug combinations was investigated, using the same infection model and 25, 50, 75 or 100 mg/kg/day (mpk) of benznidazole in combination with 5, 10 or 20 mpk of posaconazole, given alone or concomitantly for 20 days. The effects of the combination treatments on parasitological cures were higher than the sum of such effects when the drugs were administered separately at the same doses, indicating synergistic activity. Finally, sequential therapy experiments were carried out with benznidazole or posaconazole over a short interval (10 days), followed by the second drug administered for the same period of time. It was found that the sequence of benznidazole (100 mpk) followed by posaconazole (20 mpk) provided cure rates comparable to those obtained with the full (20 days) treatments with either drug alone, and no cure was observed for the short treatments with drugs given alone. Conclusions Our data demonstrate the importance of investigating the potential beneficial effects of combination treatments with marketed compounds, and showed that combinations of benznidazole with posaconazole have a positive interaction in murine models of Chagas disease. In this study, we investigated the efficacy of posaconazole in combination with benznidazole against Trypanosoma cruzi acute infections in mice, to support the potential clinical evaluation of such combination therapy for Chagas disease. The curative action of benznidazole/posaconazole combinations was explored in an established acute infection model with the Y strain in which benznidazole and posaconazole treatments induced a 70% and 80% cure rate, respectively, when administered alone at optimal doses. When tested in combination, a 80% to 90% cure rate was detected in mice receiving 25, 50 or 75 mpk of benznidazole, plus 5 or 10 mpk of posaconazole, while treatment with the sub-optimal doses of the drugs given alone induced only 0–43% cures, indicating synergistic effects. Finally, sequential short (10 days) treatments with benznidazole (100 mpk) followed by posaconazole (20 mpk) led to an 80% cure rate, comparable with full-length treatments with either drug given alone, while no cures were observed for short treatments with single drugs. Our results demonstrate that it is possible to achieve the same or better therapeutic effect using lower dosages of posaconazole and benznidazole in combination, decreasing treatment costs and potential toxicity.
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Affiliation(s)
- Lívia de Figueiredo Diniz
- Laboratório de Doença de Chagas, Departamento de Ciências Biológicas & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
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Perez-Mazliah DE, Alvarez MG, Cooley G, Lococo BE, Bertocchi G, Petti M, Albareda MC, Armenti AH, Tarleton RL, Laucella SA, Viotti R. Sequential combined treatment with allopurinol and benznidazole in the chronic phase of Trypanosoma cruzi infection: a pilot study. J Antimicrob Chemother 2012; 68:424-37. [PMID: 23104493 DOI: 10.1093/jac/dks390] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVES Even though the use of combined drugs has been proved to be effective in other chronic infections, assessment of combined treatment of antiparasitic drugs in human Chagas' disease has not been performed. Herein, a pilot study was conducted to evaluate the tolerance and side effects of a sequential combined treatment of two antiparasitic drugs, allopurinol and benznidazole, in the chronic phase of Trypanosoma cruzi infection. PATIENTS AND METHODS Changes in total and T. cruzi-specific T and B cells were monitored during a median follow-up of 36 months. Allopurinol was administered for 3 months (600 mg/day) followed by 30 days of benznidazole (5 mg/kg/day) in 11 T. cruzi-infected subjects. RESULTS The combined sequential treatment of allopurinol and benznidazole was well tolerated. The levels of T. cruzi-specific antibodies significantly decreased after sequential combined treatment, as determined by conventional serology and by a multiplex assay using recombinant proteins. The frequency of T. cruzi-specific interferon-γ-producing T cells significantly increased after allopurinol treatment and decreased to background levels following benznidazole administration in a substantial proportion of subjects evaluated. The levels of total naive (CD45RA + CCR7 + CD62L+) CD4 + and CD8 + T cells were restored after allopurinol administration and maintained after completion of the combined drug protocol, along with a decrease in T cell activation in total peripheral CD4 + and CD8 + T cells. CONCLUSIONS This pilot study shows that the combination of allopurinol and benznidazole induces significant modifications in T and B cell responses indicative of a reduction in parasite burden, and sustains the feasibility of administration of two antiparasitic drugs in the chronic phase of Chagas' disease.
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Affiliation(s)
- D E Perez-Mazliah
- Instituto Nacional de Parasitología Dr. Mario Fatala Chaben, Av. Paseo Colón 568, Buenos Aires (1063), Argentina
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Preclinical monitoring of drug association in experimental chemotherapy of Chagas' disease by a new HPLC-UV method. Antimicrob Agents Chemother 2012; 56:3344-8. [PMID: 22450981 DOI: 10.1128/aac.05785-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A combination of drugs in experimental chemotherapy of Chagas' disease may increase the effectiveness of treatment. To evaluate the possible mechanisms that influence the improvement of therapy, we investigated the pharmacokinetic interaction between benznidazole and itraconazole in a murine model treated orally with single doses of 5 mg of each compound separately or together. Blood samples from treated mice were collected at different intervals for 48 h, and a high-performance liquid chromatography (HPLC)-UV method was used to quantify both drugs in the plasma. A decrease of 1.5-fold in the maximum drug concentration in the plasma (C(max)) and an increase of 2.66-fold in the volume of distribution (V) and 7.5-fold in the elimination half-life (t(1/2β)) of benznidazole when coadministered with itraconazole were observed. The parameters area under the curve (AUC(0-t)), area under the curve extrapolated to infinity (AUC(0-∞)), time to maximum concentration of drug in serum (T(max)), and clearance (CL) for benznidazole were not significantly different in this therapeutic regime. None of the evaluated parameters for ITC demonstrated a significant difference between isolated and associated administration. These results suggest that the main effect of this interaction leads to accumulation of benznidazole in the biological system. This effect may contribute to the improved therapeutic efficacy of this combination of drugs, in addition to synergism of the different mechanisms of action of benznidazole and itraconazole against Trypanosoma cruzi in vivo.
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Experimental chemotherapy and approaches to drug discovery for Trypanosoma cruzi infection. ADVANCES IN PARASITOLOGY 2011; 75:89-119. [PMID: 21820553 DOI: 10.1016/b978-0-12-385863-4.00005-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In the 100 years since the discovery of Chagas disease, only two drugs have been developed and introduced into clinical practice, and these drugs were introduced over 40 years ago. The tools of drug discovery have improved dramatically in the interim; however, this has not translated into new drugs for Chagas disease. This has been largely because the main practitioners of drug discovery are pharmaceutical companies who are not financially motivated to invest in Chagas disease and other "orphan" diseases. As a result, it has largely been up to academic groups to bring drug candidates through the discovery pipeline and to clinical trials. The difficulty with drug discovery in academia has been the challenge of bringing together the diverse expertise in biology, chemistry, and pharmacology in concerted efforts towards a common goal of developing therapeutics. Funding is often inadequate, but lack of coordination amongst academic investigators with different expertise has also contributed to the slow progress. The purpose of this chapter is to provide an overview of approaches that can be accomplished in academic settings for preclinical drug discovery for Chagas disease. The chapter addresses methods of drug screening against Trypanosoma cruzi cultures and in animal models and includes general topics on compound selection, testing for drug-like properties (including oral bioavailability), investigating the pharmacokinetics and toxicity of compounds, and finally providing parameters to help with triaging compounds.
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21
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Lara D, Feng Y, Bader J, Savage PB, Maldonado RA. Anti-trypanosomatid activity of ceragenins. J Parasitol 2010; 96:638-42. [PMID: 19958044 DOI: 10.1645/ge-2329.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Cationic steroid antibiotics (CSAs), or ceragenins, are amphiphilic compounds consisting of a cholic acid backbone that is attached to several cationic amines. In this study, we tested the hypothesis that CSAs possess antiparasitic activities with minimal to no effects on mammalian cells, and thus could be used as potential therapeutic agents against pathogenic trypanosomatids. To investigate this notion, we synthesized CSAs and determined their trypanocidal and leishmanicidal activities in vitro. The 3 ceragenins assayed, i.e., CSA-8, CSA-13, and CSA-54, showed several degrees of parasiticidal activity. CSA-13 was the most effective compound against Leishmania major promastigotes and Trypanosoma cruzi trypomastigotes, at LD(50) 4.9 and 9 microM, respectively. The trypanocidal activities of these ceragenins were also assessed by infectivity experiments. We found CSA-8 was more effective on T. cruzi intracellular amastigotes when the infected host cells were treated for 24 hr (LD(50), 6.7 microM). Macrophages and LLC-MK(2) (treated for 72 hr) showed relative low susceptibility to these compounds. Our results suggest that ceragenins are indeed promising chemotherapeutic agents against trypanosomatids, but they require further investigation.
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Affiliation(s)
- Diana Lara
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, 500 W University Avenue, El Paso, Texas 79968, USA
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Cabral MMO, Barbosa-Filho JM, Maia GLA, Chaves MCO, Braga MV, De Souza W, Soares ROA. Neolignans from plants in northeastern Brazil (Lauraceae) with activity against Trypanosoma cruzi. Exp Parasitol 2009; 124:319-24. [PMID: 19944690 DOI: 10.1016/j.exppara.2009.11.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 10/20/2009] [Accepted: 11/17/2009] [Indexed: 11/19/2022]
Abstract
Trypanosoma cruzi is the ethiological agent for Chagas disease in Latin America. This study aimed to test the trypanocidal effect of licarin A and burchellin isolated from plants in northeastern Brazil. These neolignans were tested on T. cruzi and on peritoneal macrophages, to evaluate drug toxicity. Epimastigote growth was inhibited in 45% with licarin A and 20% with burchellin with an IC(50)/96 h of 462.7 microM and 756 microM, respectively. Epimastigotes treated with licarin A presented swollen mitochondria and disorganized mitochondrial cristae, kDNA and Golgi complex. When treated with burchellin, they presented enormous autophagosomes and chromatin disorganization. Licarin A and burchellin were able to induce trypomastigote death with IC(50)/24 h of 960 microM and 520 microM, respectively. Although licarin A presented an IC(50) for trypomastigotes higher than for epimastigotes, both substances acted as therapeutic trypanocidal agents, because they were able to kill parasites without affecting macrophages. Due to our results, burchellin and licarin A need to be further analysed to observe if they may be used as alternative blood additive prophylaxis against Chagas disease, since it has been established that blood transfusion is an important mechanism in the transmission process.
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Affiliation(s)
- M M O Cabral
- Laboratório de Diptera, Instituto Oswaldo Cruz, FIOCRUZ, Av. Brasil, 4365, 21045-900 Rio de Janeiro, RJ, Brazil.
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Abstract
The protozoan parasitesTrypanosoma bruceiandTrypanosoma cruziare the causative agents of African trypanosomiasis and Chagas disease, respectively. These are debilitating infections that exert a considerable health burden on some of the poorest people on the planet. Treatment of trypanosome infections is dependent on a small number of drugs that have limited efficacy and can cause severe side effects. Here, we review the properties of these drugs and describe new findings on their modes of action and the mechanisms by which resistance can arise. We further outline how a greater understanding of parasite biology is being exploited in the search for novel chemotherapeutic agents. This effort is being facilitated by new research networks that involve academic and biotechnology/pharmaceutical organisations, supported by public–private partnerships, and are bringing a new dynamism and purpose to the search for trypanocidal agents.
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Cavalli A, Bolognesi ML. Neglected Tropical Diseases: Multi-Target-Directed Ligands in the Search for Novel Lead Candidates against Trypanosoma and Leishmania. J Med Chem 2009; 52:7339-59. [DOI: 10.1021/jm9004835] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Andrea Cavalli
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
- Department of Drug Discovery and Development, Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
| | - Maria Laura Bolognesi
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
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Soeiro MNC, de Castro SL. Trypanosoma cruzitargets for new chemotherapeutic approaches. Expert Opin Ther Targets 2008; 13:105-21. [DOI: 10.1517/14728220802623881] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Buckner FS. Sterol 14-demethylase inhibitors for Trypanosoma cruzi infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 625:61-80. [PMID: 18365659 DOI: 10.1007/978-0-387-77570-8_6] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chagas disease is caused by infection with the protozoan pathogen, Trypanosoma cruzi. The only approved therapeutics for treating Chagas disease are two nitroheterocyclic compounds (benznidazole and nifurtimox) that are suboptimal due to poor curative activity for chronic Chagas disease and high rates of adverse drug reactions. Sterol 14-demethylase inhibitors include azole antifungal drugs such as ketoconazole, fluconazole, itraconazole, and others. The first reports of potent activity of azole antifungal drugs against Trypanosoma cruzi came out about 25 years ago. Since then, a sizeable literature has accumulated on this topic. Newer triazole compounds such as posaconazole and D0870 have been shown to be effective at curing mice with chronic Trypanosoma cruzi infection. Small clinical studies with-ketoconazole or itraconazole in humans with chronic Chagas disease have not demonstrated significant curative activity. However, there is good reason for optimism that newer compounds with greater potency and improved pharmacokinetic properties might be more efficacious. Data have been published demonstrating synergistic activity of azole drugs with various other compounds, indicating that combination chemotherapy may be an effective strategy as this field moves ahead. In light of the near absence of adequate therapeutics for curing patients with chronic Chagas disease, additional effort to develop better drugs needs to be a priority.
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Porcal W, Hernández P, Boiani L, Boiani M, Ferreira A, Chidichimo A, Cazzulo JJ, Olea-Azar C, González M, Cerecetto H. New trypanocidal hybrid compounds from the association of hydrazone moieties and benzofuroxan heterocycle. Bioorg Med Chem 2008; 16:6995-7004. [PMID: 18547811 DOI: 10.1016/j.bmc.2008.05.038] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 05/16/2008] [Accepted: 05/16/2008] [Indexed: 11/30/2022]
Abstract
Hybrid compounds containing hydrazones and benzofuroxan pharmacophores were designed as potential Trypanosoma cruzi-enzyme inhibitors. The majority of the designed compounds was successfully synthesized and biologically evaluated displaying remarkable in vitro activity against different strains of T. cruzi. Unspecific cytotoxicity was evaluated using mouse macrophages, displaying isothiosemicarbazone 10 and thiosemicarbazone 12 selectivity indexes (macrophage/parasite) of 21 and 27, respectively. In addition, the mode of anti-trypanosomal action of the derivatives was investigated. Some of these derivatives were moderate inhibitors of cysteinyl active site enzymes of T. cruzi, cruzipain and trypanothione reductase. ESR experiments using T. cruzi microsomal fraction suggest that the main mechanism of action of the trypanocidal effects is the production of oxidative stress into the parasite.
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Affiliation(s)
- Williams Porcal
- Departamento de Química Orgánica, Facultad de Ciencias-Facultad de Química, Igua 4225, 11400 Montevideo, Uruguay
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28
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Cammerer SB, Jimenez C, Jones S, Gros L, Lorente SO, Rodrigues C, Rodrigues JCF, Caldera A, Ruiz Perez LM, da Souza W, Kaiser M, Brun R, Urbina JA, Gonzalez Pacanowska D, Gilbert IH. Quinuclidine derivatives as potential antiparasitics. Antimicrob Agents Chemother 2007; 51:4049-61. [PMID: 17709461 PMCID: PMC2151445 DOI: 10.1128/aac.00205-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There is an urgent need for the development of new drugs for the treatment of tropical parasitic diseases such as Chagas' disease and leishmaniasis. One potential drug target in the organisms that cause these diseases is sterol biosynthesis. This paper describes the design and synthesis of quinuclidine derivatives as potential inhibitors of a key enzyme in sterol biosynthesis, squalene synthase (SQS). A number of compounds that were inhibitors of the recombinant Leishmania major SQS at submicromolar concentrations were discovered. Some of these compounds were also selective for the parasite enzyme rather than the homologous human enzyme. The compounds inhibited the growth of and sterol biosynthesis in Leishmania parasites. In addition, we identified other quinuclidine derivatives that inhibit the growth of Trypanosoma brucei (the causative organism of human African trypanosomiasis) and Plasmodium falciparum (a causative agent of malaria), but through an unknown mode(s) of action.
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29
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Rolón M, Seco EM, Vega C, Nogal JJ, Escario JA, Gómez-Barrio A, Malpartida F. Selective activity of polyene macrolides produced by genetically modified Streptomyces on Trypanosoma cruzi. Int J Antimicrob Agents 2006; 28:104-9. [PMID: 16844353 DOI: 10.1016/j.ijantimicag.2006.02.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 02/13/2006] [Indexed: 11/15/2022]
Abstract
The growth inhibitory effects on Trypanosoma cruzi of several natural tetraene macrolides and their derivatives were studied and compared with that of amphotericin B. All tetraenes strongly inhibited in vitro multiplication. Proliferation of epimastigotes was arrested by all these drugs at < or =3.6 microM, which were also active on amastigotes proliferating in fibroblasts. Compared with amphotericin B, the compounds were less effective but also less toxic, showing no effect on the proliferation of J774 and NCTC 929 mammalian cells at concentrations active against the parasites. CE-108B (a polyene amide) appeared to be an especially potent trypanocidal compound, with strong in vivo trypanocidal activity and very low or no toxic side effects, and thus should be considered for further studies.
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Affiliation(s)
- Miriam Rolón
- Departamento de Parasitología, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
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30
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Hankins EG, Gillespie JR, Aikenhead K, Buckner FS. Upregulation of sterol C14-demethylase expression in Trypanosoma cruzi treated with sterol biosynthesis inhibitors. Mol Biochem Parasitol 2005; 144:68-75. [PMID: 16165233 DOI: 10.1016/j.molbiopara.2005.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 08/01/2005] [Accepted: 08/03/2005] [Indexed: 11/26/2022]
Abstract
Infection with the protozoan, Trypanosoma cruzi, is the cause of Chagas disease that occurs widely throughout Latin America. T. cruzi contains sterol biosynthesis enzymes, and produces sterol products similar to those found in fungi. Antifungal drugs that inhibit ergosterol biosynthesis have potent anti-T. cruzi activity in vitro and in animal models. In this report, we describe the effects of sterol biosynthesis inhibitors (simvistatin, zaragosic acid, terbinafine, a lanosterol synthase inhibitor, ketoconazole, and tridemorph) on the regulation of two sterol biosynthesis genes and their protein products. Culturing T. cruzi in the presence of the lanosterol synthase inhibitor, terbinafine, or ketoconazole increased mRNA levels of the sterol C14-demethylase gene approximately 7-12-fold. The sterol C14-demethylase protein levels were also elevated. The effects of the sterol biosynthesis inhibitors on hydroxymethylglutaryl-CoA reductase expression were minimal. Control of the upregulation of sterol C14-demethylase appears to be mediated through the 3'-untranslated region of the gene. The findings demonstrate that T. cruzi can specifically regulate gene expression in response to derangements in its cellular functions.
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Affiliation(s)
- Eleanor G Hankins
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
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31
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Orenes Lorente S, Gómez R, Jiménez C, Cammerer S, Yardley V, de Luca-Fradley K, Croft SL, Ruiz Perez LM, Urbina J, Gonzalez Pacanowska D, Gilbert IH. Biphenylquinuclidines as inhibitors of squalene synthase and growth of parasitic protozoa. Bioorg Med Chem 2005; 13:3519-29. [PMID: 15848765 DOI: 10.1016/j.bmc.2005.02.060] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Accepted: 02/22/2005] [Indexed: 11/30/2022]
Abstract
In this paper we describe the preparation of some biphenylquinuclidine derivatives and their evaluation as inhibitors of squalene synthase in order to explore their potential in the treatment of the parasitic diseases leishmaniasis and Chagas disease. The compounds were screened against recombinant Leishmania major squalene synthase and against Leishmania mexicana promastigotes, Leishmania donovani intracellular amastigotes and Trypanosoma cruzi intracellular amastigotes. Compounds that inhibited the enzyme, also reduced the levels of steroids and caused growth inhibition of L. mexicana promastigotes. However there was a lower correlation between inhibition of the enzyme and growth inhibition of the intracellular parasites, possibly due to delivery problems. Some compounds also showed growth inhibition of T. brucei rhodesiense trypomastigotes, although in this case alternative modes of action other than inhibition of SQS are probably involved.
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Affiliation(s)
- Silvia Orenes Lorente
- Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3XF, UK
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32
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Santa-Rita RM, Lira R, Barbosa HS, Urbina JA, de Castro SL. Anti-proliferative synergy of lysophospholipid analogues and ketoconazole against Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae): cellular and ultrastructural analysis. J Antimicrob Chemother 2005; 55:780-4. [PMID: 15790672 DOI: 10.1093/jac/dki087] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Investigation of the antiproliferative synergy of the lysophospholipid analogues (LPAs) edelfosine, ilmofosine and miltefosine with the ergosterol biosynthesis inhibitor ketoconazole against Trypanosoma cruzi. METHODS The effect of LPAs, ketoconazole and their combination was evaluated against epimastigotes and intracellular amastigotes by the parameter IC50 leading to construction of isobolograms, for determination of a synergic effect. For epimastigotes, ultrastructural damage induced by these treatments was evaluated by transmission and scanning electron microscopy. RESULTS Synergy was confirmed against both epimastigotes and amastigotes of the parasite. Edelfosine or ketoconazole alone induced morphological alterations in the plasma membrane and reservosomes of the parasites, while in combination, they also led to severe mitochondrial damage, formation of autophagic structures and multinucleation. Scanning electron microscopy confirmed the effect at the plasma membrane and also revealed alterations in the shape of the parasites. CONCLUSIONS Our results describe the synergic anti-proliferative effect of LPAs and ketoconazole against epimastigotes and intracellular amastigotes and suggest that in epimastigotes, plasma membrane, reservosomes and mitochondria are targets of these drugs, possibly by interference with lipid metabolism.
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Affiliation(s)
- Ricardo M Santa-Rita
- Departmento de Ultra-estrutura e Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, CP 926, 21045-900, Rio de Janeiro, Brazil
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33
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Docampo R, Schmuñis GA. Sterol biosynthesis inhibitors: potential chemotherapeutics against Chagas disease. ACTA ACUST UNITED AC 2005; 13:129-30. [PMID: 15275097 DOI: 10.1016/s0169-4758(97)01021-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- R Docampo
- Laboratory of Molecular Parasitology, Department of Pothobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA.
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34
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Peña-Diaz J, Montalvetti A, Flores CL, Constán A, Hurtado-Guerrero R, De Souza W, Gancedo C, Ruiz-Perez LM, Gonzalez-Pacanowska D. Mitochondrial localization of the mevalonate pathway enzyme 3-Hydroxy-3-methyl-glutaryl-CoA reductase in the Trypanosomatidae. Mol Biol Cell 2003; 15:1356-63. [PMID: 14699057 PMCID: PMC363142 DOI: 10.1091/mbc.e03-10-0720] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
3-Hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) is a key enzyme in the sterol biosynthesis pathway, but its subcellular distribution in the Trypanosomatidae family is somewhat controversial. Trypanosoma cruzi and Leishmania HMGRs are closely related in their catalytic domains to bacterial and eukaryotic enzymes described but lack an amino-terminal domain responsible for the attachment to the endoplasmic reticulum. In the present study, digitonin-titration experiments together with immunoelectron microscopy were used to establish the intracellular localization of HMGR in these pathogens. Results obtained with wild-type cells and transfectants overexpressing the enzyme established that HMGR in both T. cruzi and Leishmania major is localized primarily in the mitochondrion and that elimination of the mitochondrial targeting sequence in Leishmania leads to protein accumulation in the cytosolic compartment. Furthermore, T. cruzi HMGR is efficiently targeted to the mitochondrion in yeast cells. Thus, when the gene encoding T. cruzi HMGR was expressed in a hmg1 hmg2 mutant of Saccharomyces cerevisiae, the mevalonate auxotrophy of mutant cells was relieved, and immunoelectron analysis showed that the parasite enzyme exhibits a mitochondrial localization, suggesting a conservation between the targeting signals of both organisms.
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Affiliation(s)
- Javier Peña-Diaz
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, 18001 Granada, Spain
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35
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Sampaio RNR, Takano GHS, Malacarne ACB, Pereira TR, de Magalhães AV. [In vivo Terbinafine inefficacy on cutaneous leishmaniasis caused by Leishmania (Leishmania) amazonensis in C57BL/6 mice]. Rev Soc Bras Med Trop 2003; 36:531-3. [PMID: 12937735 DOI: 10.1590/s0037-86822003000400018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The efficiency of terbinafine was tested in C57BL/6 mice inoculated with the Leishmania (Leishmania) amazonensis strain MHOM/BR/PH8. The mice were administered: terbinafine at a dose of 100mg/kg/d by via oral; 0.9% saline solution orally as the control; and subcutaneous sodium stibogluconate 400mg SbV/kg/d as gold standard, for 20 days. Terbinafine was demonstrated to be ineffective when compared to the controls, using clinical and parasitological parameters and the limiting dilution assay.
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36
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Roberts CW, McLeod R, Rice DW, Ginger M, Chance ML, Goad LJ. Fatty acid and sterol metabolism: potential antimicrobial targets in apicomplexan and trypanosomatid parasitic protozoa. Mol Biochem Parasitol 2003; 126:129-42. [PMID: 12615312 DOI: 10.1016/s0166-6851(02)00280-3] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Current treatments for diseases caused by apicomplexan and trypanosomatid parasites are inadequate due to toxicity, the development of drug resistance and an inability to eliminate all life cycle stages of these parasites from the host. New therapeutics agents are urgently required. It has recently been demonstrated that type II fatty acid biosynthesis occurs in the plastid of Plasmodium falciparum and Toxoplasma gondii and inhibitors of this pathway such as triclosan and thiolactomycin restrict their growth. Furthermore, Trypanosoma brucei has recently been demonstrated to use type II fatty acid biosynthesis for myristate synthesis and to be susceptible to thiolactomycin. As this pathway is absent from mammals, it may provide an excellent target for novel antimicrobial agents to combat these diverse parasites. Leishmania and Trypanosoma parasites produce ergosterol-related sterols by a biosynthetic pathway similar to that operating in pathogenic fungi and their growth is susceptible to sterol biosynthesis inhibitors. Thus, inhibition of squalene 2,3-epoxidase by terbinafine, 14alpha-methylsterol 14-demethylase by azole and triazole compounds and delta(24)-sterol methyl transferase by azasterols all cause a depletion of normal sterols and an accumulation of abnormal amounts of sterol precursors with cytostatic or cytoxic consequences. However, Leishmania parasites can survive with greatly altered sterol profiles induced by continuous treatment with low concentrations of some inhibitors and they also have some ability to utilise and metabolise host sterol. These properties may permit the parasites to evade treatment with sterol biosynthesis inhibitors in some clinical situations and need to be taken into account in the design of future drugs.
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Affiliation(s)
- C W Roberts
- Department of Immunology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, Glasgow G4 ONR, Scotland, UK.
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37
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Abstract
Pneumocystis lacks ergosterol, and several antimycotics that bind ergosterol in fungal membranes or inhibit its synthesis are ineffective against Pneumocystis pneumonia. The organism synthesizes C(28) and C(29) Delta(7) 24-alkylsterols, 24-alkyllanosterol derivatives, and Delta(5) 24-alkylsterols, which may be produced by modifying scavenged Delta(5) sterols. Mammals cannot desaturate C-22 and alkylate C-24 of sterols, thus, these processes are particularly attractive targets for antifungal drug development. Recent data indicate that C-22 desaturation is not, but C-24 alkylation is an attractive target in P. carinii. The P. carinii S-adenosyl-L-methionine:sterol C-24 methyl transferase (SAM:SMT) has unique properties; it prefers lanosterol as its sterol substrate.
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Affiliation(s)
- Edna S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, OH 45221, USA.
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38
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Navarro M, Cisneros-Fajardo EJ, Lehmann T, Sánchez-Delgado RA, Atencio R, Silva P, Lira R, Urbina JA. Toward a novel metal-based chemotherapy against tropical diseases. 6. Synthesis and characterization of new copper(II) and gold(I) clotrimazole and ketoconazole complexes and evaluation of their activity against Trypanosoma cruzi. Inorg Chem 2001; 40:6879-84. [PMID: 11754267 DOI: 10.1021/ic0103087] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The complexes [Cu(CTZ)(4)]Cl(2).2H(2)O (1), [Cu(CTZ)Cl(2)](2) (2), [Cu(KTZ)(3)Cl(2)] (3), and [Cu(KTZ)Cl(2)](2).2H(2)O (4) were prepared by reaction of CuCl(2) with CTZ and KTZ (where CTZ = 1-[[(2-chlorophenyl)diphenyl]methyl]-1H-imidazole and KTZ = cis-1-acetyl-4-[4-[[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]piperazine), respectively, in acetonitrile at different ligand to metal molar ratios. Gold complexes [Au(PPh(3))(CTZ)]PF(6) (5) and [Au(PPh(3))(KTZ)]PF(6).H(2)O (6) were synthesized by reaction of AuClPPh(3), with KPF(6) and CTZ or KTZ in acetonitrile. All the new compounds were characterized by NMR spectroscopy and microanalytical methods, and for the paramagnetic species EPR spectroscopy and DC magnetic susceptibility measurements were also employed. The solid-state structure of 1 has been determined by X-ray crystallography. 1 crystallizes in the triclinic space group P(-)1, with a = 12.773(2) A, b = 15.326(4) A, c = 11.641(2) A, V = 1957.4(7) A(3), Z = 1, and D(calcd) = 1.284 g/cm(3). The structure refinement converged at R1 = 0.0731 and wR2 = 0.1962. Complex 1 displayed a square-planar structure typical for tetrakis(imidazole)copper(II) complexes. The new compounds were tested for in vitro activity against cultures of epimastigotes of Trypanosoma cruzi, the causative agent of Chagas disease. At concentrations equivalent to 10(-6) M of total CTZ or KTZ (in DMSO) all the complexes exhibited significantly higher growth inhibitory activity than their respective parental compounds.
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Affiliation(s)
- M Navarro
- Chemistry Center, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas 1020-A, Venezuela.
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Vannier-Santos MA, Lins U. Cytochemical techniques and energy-filtering transmission electron microscopy applied to the study of parasitic protozoa. Biol Proced Online 2001; 3:8-18. [PMID: 12734583 PMCID: PMC145542 DOI: 10.1251/bpo19] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2001] [Revised: 07/27/2001] [Accepted: 07/30/2001] [Indexed: 12/02/2022] Open
Abstract
The study of parasitic protozoa plays a major role in cell biology, biochemistry and molecular biology. Numerous cytochemical techniques have been developed in order to unequivocally identify the nature of subcellular compartments. Enzyme and immuno-cytochemistry allow the detection of, respectively, enzymatic activity products and antigens in particular sites within the cell. Energy-filtering transmission electron microscopy permits the detection of specific elements within such compartments. These approaches are particularly useful for studies employing antimicrobial agents where cellular compartments may be destroyed or remarkably altered and thus hardly identified by standard methods of observation. In this regard cytochemical and spectroscopic techniques provide valuable data allowing the determination of the mechanisms of action of such compounds.
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Affiliation(s)
- Marcos A Vannier-Santos
- Lab. Biologia Celular Parasitária, Programa de Biologia Celular e Parasitologia, Instituto de Biofísica Carlos Chagas Filho. Universidade Federal do Rio de Janeiro, C.C.S. bloco G, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, 21949-900. Brazil.Instituto de Microbiologia Prof. Paulo de Góes. Universidade Federal do Rio de Janeiro. Brazil.
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40
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Lira R, Contreras LM, Rita RM, Urbina JA. Mechanism of action of anti-proliferative lysophospholipid analogues against the protozoan parasite Trypanosoma cruzi: potentiation of in vitro activity by the sterol biosynthesis inhibitor ketoconazole. J Antimicrob Chemother 2001; 47:537-46. [PMID: 11328763 DOI: 10.1093/jac/47.5.537] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigated the mechanism of action of metabolically stable lysophospholipid analogues (LPAs), with potent anti-tumour and anti-protozoal activity against Trypanosoma cruzi, the causative agent of Chagas' disease. Against the axenically grown epimastigote form of the parasite, the IC(50)s after 120 h for ET-18-OCH(3), miltefosine and ilmofosine were 3, 1 and 3 microM, respectively; at higher concentrations immediate lytic effects were observed. Eradication of the intracellular amastigote, grown inside Vero cells, was achieved at 0.1, 0.1 and 1 microM for ET-18-OCH(3), miltefosine and ilmofosine, respectively. Analysis of the lipid composition of epimastigotes exposed to LPAs at their IC(50) for 120 h showed that the ratio of phosphatidyl-choline (PC) to phosphatidylethanolamine (PE) changed from 1.5 in control cells to c. 0.67 in those treated with the analogues. A significant increase in the content of phosphatidylserine was also observed in treated cells. Intact epimastigotes efficiently incorporated radioactivity from L-[methyl-(14)C]methionine into PC, but not from [methyl-(14)C]choline. ET-18-OCH(3) inhibited the incorporation of L-[methyl-(14)C]methionine into PC with an IC(50) of 2 microM, suggesting that inhibition of the de novo synthesis through the Greenberg's pathway was a primary effect underlying the selective anti-parasitic activity of this compound. Antiproliferative synergism was observed as a consequence of combined treatment of epimastigotes with ET-18-OCH(3) and ketoconazole, a sterol biosynthesis inhibitor, probably due to the fact that a secondary effect of the latter is also a blockade of PC synthesis at the level of PE-PC-N-methyl-transferase.
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Affiliation(s)
- R Lira
- Laboratorio de Química Biológica, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Apartado 21827, Caracas 1020A, Venezuela
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41
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Navarro M, Lehmann T, Cisneros-Fajardo EJ, Fuentes A, Sánchez-Delgado RA, Silva P, Urbina JA. Toward a novel metal-based chemotherapy against tropical diseases. Polyhedron 2000. [DOI: 10.1016/s0277-5387(00)00495-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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42
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Urbina JA. Parasitological cure of Chagas disease: is it possible? Is it relevant? Mem Inst Oswaldo Cruz 2000; 94 Suppl 1:349-55. [PMID: 10677754 DOI: 10.1590/s0074-02761999000700068] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- J A Urbina
- Laboratorio de Química Biológica, Centro de Bioquímica y Biofísica, Instituto Venezolano de Invstigaciones Cientificas, Caracas, Venezuela.
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Urbina JA, Lira R, Visbal G, Bartrolí J. In vitro antiproliferative effects and mechanism of action of the new triazole derivative UR-9825 against the protozoan parasite Trypanosoma (Schizotrypanum) cruzi. Antimicrob Agents Chemother 2000; 44:2498-502. [PMID: 10952601 PMCID: PMC90091 DOI: 10.1128/aac.44.9.2498-2502.2000] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We describe the in vitro antiproliferative effects of the new triazole derivative UR-9825 against the protozoan parasite Trypanosoma (Schizotrypanum) cruzi, the causative agent of Chagas' disease in Latin America. The compound was found to be extremely active against the cultured (epimastigote) form of the parasite, equivalent to that present in the reduviid vector, with a MIC of 30 nM, a concentration 33-fold lower than that required with the reference compound ketoconazole. At that MIC, growth arrest coincided with depletion of the parasite's 4,14-desmethyl endogenous sterols (ergosterol, 24-ethylcholesta-5,7,22-trien-3b-ol, and precursors) and their replacement by methylated sterols (lanosterol, 24-methylenedihydrolanosterol, and obtusifoliol), as revealed by high-resolution gas chromatography coupled with mass spectrometry. This indicated that the primary mechanism of action of UR-9825 was inhibition of the parasite's sterol C14alpha demethylase, as seen with other azole derivatives. The phospholipid composition of growth-arrested epimastigotes was also altered, when compared to controls, with a significant increase in the content of phosphatidylethanolamine and phosphatidylserine and a concomitant reduction of the content of phosphatidylcholine. The clinically relevant intracellular amastigote form, grown in cultured Vero cells at 37 degrees C, was even more sensitive to UR-9825, with a MIC of 10 nM, comparable to that for ketoconazole. The results showed that UR-9825 is among the most potent azole derivatives tested against this parasite and support in vivo studies with this compound.
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Affiliation(s)
- J A Urbina
- Laboratorio de Química Biológica, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
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Molina J, Martins-Filho O, Brener Z, Romanha AJ, Loebenberg D, Urbina JA. Activities of the triazole derivative SCH 56592 (posaconazole) against drug-resistant strains of the protozoan parasite Trypanosoma (Schizotrypanum) cruzi in immunocompetent and immunosuppressed murine hosts. Antimicrob Agents Chemother 2000; 44:150-5. [PMID: 10602737 PMCID: PMC89642 DOI: 10.1128/aac.44.1.150-155.2000] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/1999] [Accepted: 10/25/1999] [Indexed: 11/20/2022] Open
Abstract
We have studied the in vivo activity of the new experimental triazole derivative SCH 56592 (posaconazole) against a variety of strains of the protozoan parasite Trypanosoma (Schizotrypanum) cruzi, the causative agent of Chagas' disease, in both immunocompetent and immunosuppressed murine hosts. The T. cruzi strains used in the study were previously characterized as susceptible (CL), partially resistant (Y), or highly resistant (Colombiana, SC-28, and VL-10) to the drugs currently in clinical use, nifurtimox and benznidazole. Furthermore, all strains are completely resistant to conventional antifungal azoles, such as ketoconazole. In the first study, acute infections with the CL, Y, and Colombiana strains in both normal and cyclophosphamide-immunosuppressed mice were treated orally, starting 4 days postinfection (p.i.), for 20 consecutive daily doses. The results indicated that in immunocompetent animals SCH 56592 at 20 mg/kg of body weight/day provided protection (80 to 90%) against death caused by all strains, a level comparable or superior to that provided by the optimal dose of benznidazole (100 mg/kg/day). Evaluation of parasitological cure revealed that SCH 56592 was able to cure 90 to 100% of the surviving animals infected with the CL and Y strains and 50% of those which received the benznidazole- and nifurtimox-resistant Colombiana strain. Immunosuppression markedly reduced the mean survival time of untreated mice infected with any of the strains, but this was not observed for the groups which received SCH 56592 at 20 mg/kg/day or benznidazole at 100 mg/kg/day. However, the overall cure rates were higher for animals treated with SCH 56592 than among those treated with benznidazole. The results were confirmed in a second study, using the same model but a longer (43-dose) treatment period. Finally, a model for the chronic disease in which oral treatment was started 120 days p.i. and consisted of 20 daily consecutive doses was investigated. The results showed that SCH 56592 at 20 mg/kg/day was able to induce a statistically significant increase in survival of animals infected with all strains, while benznidazole at 100 mg/kg/day was able to increase survival only in animals infected with the Colombiana strain. Moreover, the triazole was able to induce parasitological cures in 50 to 60% of surviving animals, irrespective of the infecting strain, while no cures were obtained with benznidazole. Taken together, the results demonstrate that SCH 56592 has in vivo trypanocidal activity, even against T. cruzi strains naturally resistant to nitrofurans, nitroimidazoles, and conventional antifungal azoles, and that this activity is retained to a large extent in immunosuppressed hosts.
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Affiliation(s)
- J Molina
- Laboratorio de Doença de Chagas, Centro de Pesquisas Rene Rachou, Fundaçao Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
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Liendo A, Visbal G, Piras MM, Piras R, Urbina JA. Sterol composition and biosynthesis in Trypanosoma cruzi amastigotes. Mol Biochem Parasitol 1999; 104:81-91. [PMID: 10589983 DOI: 10.1016/s0166-6851(99)00129-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A detailed analysis of the endogenous sterols present in the clinically relevant intracellular (amastigote) stages of Trypanosoma cruzi, is presented. The parasites were grown in cultured Vero cells in the absence or presence of different sterol biosynthesis inhibitors, including the C14alpha demethylase inhibitor ketoconazole and two inhibitors of delta24(25)-sterol methyl transferase, 20 piperidin-2-yl-5alpha-pregnan-3beta-20-R-diol (22,26-azasterol) and 24-(R,S),25-epiminolanosterol. Amastigotes were isolated and purified from their host cells and neutral lipids were extracted, separated and analyzed by chromatographic and mass spectrometric methods. Control (untreated) amastigotes contained as main endogenous sterols 24-methyl-cholesta-7-en-3beta-ol (ergosta-7-en-3beta-ol) and its 24-ethyl analog, plus smaller amounts of their precursor, ergosta-7,24(28)dien-3beta-ol; these cells also contained cholesterol (up to 80% by weight of total sterols), probably derived from host cells. Amastigotes that proliferated in the presence of 10 nM ketoconazole (minimal inhibitory concentration, MIC) for 24 h had a sharply reduced content of endogenous 4-desmethyl sterols with a concomitant accumulation of 24-methyl-dihydrolanosterol and 24-methylene-dihydrolanosterol. On the other hand, amastigotes incubated during the same period of time with the two inhibitors of 24(25)-SMT at their respective MICs (100-300 nM) accumulated large amounts of C27 sterols whose structure suggested, in the case of 22,26-azasterol, that delta14 sterol reductase was also inhibited. Ketoconazole produced a dose-dependent reduction in the incorporation of [2-(14)C]-acetate into the parasite's endogenous C4-desmethyl sterols with an IC50 of 50 nM, indistinguishable from the value reported previously for the extracellular epimastigote form. Taken together, the results showed that amastigotes have a simpler sterol biosynthetic pathway than that previously described for epimastigotes, lacking both delta5 and delta22 reductases. They also suggest that the 100-fold higher potency of antifungal azoles as antiproliferative agents against amastigotes, when compared with epimastigotes, is most probably due to a smaller pool of endogenous sterols in the intracellular parasites.
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Affiliation(s)
- A Liendo
- Laboratorio de Quimica Biológica, Centro de Bioquímica y Biofisica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
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Buckner FS, Wilson AJ, White TC, Van Voorhis WC. Induction of resistance to azole drugs in Trypanosoma cruzi. Antimicrob Agents Chemother 1998; 42:3245-50. [PMID: 9835521 PMCID: PMC106029 DOI: 10.1128/aac.42.12.3245] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Trypanosoma cruzi is the protozoan parasite that causes Chagas' disease, a frequently fatal illness affecting the heart and gastrointestinal systems. An estimated 16 million to 18 million people in Latin America and 50,000 to 100,000 people in the United States are infected with this pathogen. Treatment options for T. cruzi infections are suboptimal due to the toxicities and limited effectiveness of the available drugs. Azole antimicrobial agents have been discovered to have antitrypanosomal activity by inhibition of ergosterol synthesis. The triazole itraconazole was recently shown to produce a parasitologic cure rate of 53% in chronically infected patients (W. Apt et al., Am. J. Trop. Med. Hyg. 59:133-138, 1998), a result which may lead to more use of this family of drugs for the treatment of T. cruzi infections. In the experiments reported on here, resistance to azoles was induced in vitro by serial passage of mammalian-stage parasites in the presence of fluconazole for 4 months. These parasites were cross resistant to the other azoles, ketoconazole, miconazole, and itraconazole. They remained susceptible to benznidazole and amphotericin B. The azole-resistant phenotype was stable for more than 2 months of in vitro serial passage without fluconazole. In addition, the parasites resisted treatment in mice receiving ketoconazole. The rapid development of azole resistance in T. cruzi in vitro suggests that resistance to azole drugs has the potential to occur in patients and may pose an impediment to the progress being made in the treatment of T. cruzi infection.
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Affiliation(s)
- F S Buckner
- Department of Medicine, Infectious Diseases, University of Washington, Seattle, Washington 98195-7185, USA.
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Urbina JA, Payares G, Contreras LM, Liendo A, Sanoja C, Molina J, Piras M, Piras R, Perez N, Wincker P, Loebenberg D. Antiproliferative effects and mechanism of action of SCH 56592 against Trypanosoma (Schizotrypanum) cruzi: in vitro and in vivo studies. Antimicrob Agents Chemother 1998; 42:1771-7. [PMID: 9661019 PMCID: PMC105681 DOI: 10.1128/aac.42.7.1771] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We have investigated the antiproliferative effects of SCH 56592, a new experimental triazole, against Trypanosoma (Schizotrypanum) cruzi, the etiological agent of Chagas' disease in Latin America. SCH 56592 blocked the proliferation of the epimastigote form of the parasite in vitro at 30 nM, a concentration 30- to 100-fold lower than that required with the reference compounds ketoconazole and itraconazole. At that concentration all the parasite's endogenous sterols (ergosterol, 24-ethyl-cholesta-5,7,22-trien-3 beta-ol, and its 22-dihydro analogs), were replaced by methylated sterols (lanosterol and 24-methylene-dihydrolanosterol), as revealed by high-resolution gas chromatography coupled with mass spectrometry. This indicated that the primary mechanism of action of the drug was inhibition of the parasite's sterol C-14 alpha demethylase. Against the clinically relevant intracellular amastigote form, grown in cultured Vero cells at 37 degrees C, the MIC of SCH 56592 was 0.3 nM, again 33- to 100-fold lower than that of ketoconazole or itraconazole. In a murine model of acute Chagas' disease, SCH 56592 given at > or = 10 mg/kg of body weight/day for a total of 43 doses allowed 85 to 100% survival and 90 to 100% cure of the surviving animals, as verified by parasitological, serological, and PCR-based tests, while ketoconazole given at 30 mg/kg day allowed 60% survival but only 20% cure. In a murine model of chronic Chagas' disease, SCH 56592 was again more effective than ketoconazole, providing 75 to 85% protection from death, with 60 to 75% parasitological cures of the surviving animals, while no parasitological cures were observed with ketoconazole. The results indicate that SCH 56592 is the most powerful sterol biosynthesis inhibitor ever tested against T. cruzi and may be useful in the treatment of human Chagas' disease.
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Affiliation(s)
- J A Urbina
- Laboratorio de Química Biológica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
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Sánchez-Delgado RA, Navarro M, Lazardi K, Atencio R, Capparelli M, Vargas F, Urbina JA, Bouillez A, Noels AF, Masi D. Toward a novel metal based chemotherapy against tropical diseases 4. Synthesis and characterization of new metal-clotrimazole complexes and evaluation of their activity against Trypanosoma cruzi. Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(98)00114-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Toledo MJ, Guilherme AL, da Silva JC, de Gasperi MV, Mendes AP, Gomes ML, de Araújo SM. Trypanosoma cruzi: chemotherapy with benznidazole in mice inoculated with strains from Paraná state and from different endemic areas of Brazil. Rev Inst Med Trop Sao Paulo 1997; 39:283-90. [PMID: 9661307 DOI: 10.1590/s0036-46651997000500007] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Strains of Trypanosoma cruzi from different geographical areas have shown different levels of susceptibility to trypanosomicidal drugs. The susceptibility in vivo to benznidazole was investigated in eighteen strains of T. cruzi. Twelve were isolated from chronic chagasic patients from different Chagas' disease endemic areas. The other six strains were isolated from the northwestern region of Paraná state; two of them from patients, three from triatomines (Triatoma sordida) and one from wild reservoir (Didelphis sp.). To test drug the infected mice were divided into two groups of twenty. One group was treated with benznidazole for twenty consecutive days and the other group was used as untreated control. The treatment began after detection of the infection by direct blood examination or haemoculture. The control of cure was done through haemoculture and indirect immunofluorescence test. The drug eliminated the inflammatory lesions of the skeletal muscle of mice considered cured and from the heart of most of them. Moreover, the inflammatory lesions were reduced in treated but not cured animals. The T. cruzi strains studied showed a gradient of drug susceptibility that varied from 0% to 100%. Ten strains were considered sensitive to the treatment (61 to 100% of cure), one strain was partially sensitive (50% of cure) and seven strains were considered resistant to the treatment (0 to 40% of cure). This variation was observed both in strains of T. cruzi isolated from domestic and sylvatic cycles.
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Affiliation(s)
- M J Toledo
- Clinical Analysis Department, Univ. Fed. Ouro Preto, MG, Brasil
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Rangel H, Dagger F, Hernandez A, Liendo A, Urbina JA. Naturally azole-resistant Leishmania braziliensis promastigotes are rendered susceptible in the presence of terbinafine: comparative study with azole-susceptible Leishmania mexicana promastigotes. Antimicrob Agents Chemother 1996; 40:2785-91. [PMID: 9124841 PMCID: PMC163622 DOI: 10.1128/aac.40.12.2785] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Leishmania braziliensis (isolate 2903) was naturally resistant to ketoconazole or the bis-triazole D0870, inhibitors of sterol C-14 demethylase, which produced only moderate effects on the proliferation of promastigotes at 10 microM. In contrast, Leishmania mexicana (isolate NR) was extremely susceptible to the azoles, as complete growth arrest and cell lysis were induced by incubation of the parasites with 0.05 microM concentrations of the drugs for 72 h. The opposite response was observed with terbinafine, an inhibitor of squalene epoxidase: L. braziliensis 2903 was three times more susceptible to the drug than L. mexicana NR (MICs of 5 and 15 microM, respectively). However, when the L. braziliensis stock was grown in the presence of 1 microM terbinafine, which by itself produced only marginal (< 10%) effects on growth, it became highly susceptible to the azoles, with an MIC of 0.03 microM. Analysis of cellular free sterols by high-resolution capillary gas chromatography coupled to mass spectrometry showed that 14-methyl sterols can support normal growth of L. braziliensis 2903 but not of L. mexicana NR. On the other hand, the higher susceptibility of the L. braziliensis isolate to terbinafine was correlated with a massive accumulation of squalene in the presence of the allylamine while no significant effects on L. mexicana sterol composition were observed at drug concentrations up to 1 microM. Thus, the > 300-fold increase in the susceptibility of L. braziliensis promastigotes to azoles in the presence of terbinafine was attributed to the combined effect of squalene and the methylated sterol precursors on the physical properties of the cell's membranes, leading to the loss of cell viability. Combination therapy with azoles and terbinafine in the treatment of human L. braziliensis infections deserves further study.
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Affiliation(s)
- H Rangel
- Laboratorio de Bioloía Celular de Parásitos, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela
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