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Kour P, Saha P, Sharma DK, Singh K. DNA topoisomerases as a drug target in Leishmaniasis: Structural and mechanistic insights. Int J Biol Macromol 2024; 256:128401. [PMID: 38007027 DOI: 10.1016/j.ijbiomac.2023.128401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 11/09/2023] [Accepted: 11/22/2023] [Indexed: 11/27/2023]
Abstract
Leishmaniasis, caused by a protozoan parasite, is among humanity's costliest banes, owing to the high mortality and morbidity ratio in poverty-stricken areas. To date, no vaccine is available for the complete cure of the disease. Current chemotherapy is expensive, has undesirable side effects, and faces drug resistance limitations and toxicity concerns. The substantial differences in homology between leishmanial DNA topoisomerase IB compared with the human counterparts provided a new lead in the study of the structural determinants that can be targeted. Several research groups explored this molecular target, trying to fill the therapeutic gap, and came forward with various anti-leishmanial scaffolds. This article is a comprehensive review of knowledge about topoisomerases as an anti-leishmanial drug target and their inhibitors collected over the years. In addition to information on molecular targets and reported scaffolds, the review details the structure-activity relationship of described compounds with leishmanial Topoisomerase IB. Moreover, the work also includes information about the structure of the inhibitors, showing common interacting residues with leishmanial topoisomerases that drive their mode of action towards them. Finally, in search of topoisomerase inhibitors at the stage of clinical trials, we have listed all the drugs that have been in clinical trials against leishmaniasis.
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Affiliation(s)
- Parampreet Kour
- Infectious Diseases Division, CSIR- Indian Institute of Integrative Medicine, Jammu 180001, India
| | - Pallavi Saha
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology Banaras Hindu University, Varanasi 221005, India
| | - Deepak K Sharma
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology Banaras Hindu University, Varanasi 221005, India
| | - Kuljit Singh
- Infectious Diseases Division, CSIR- Indian Institute of Integrative Medicine, Jammu 180001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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Chheda PR, Nieto N, Kaur S, Beck JM, Beck JR, Honzatko R, Kerns RJ, Nelson SW. Promising antimalarials targeting apicoplast DNA polymerase from Plasmodium falciparum. Eur J Med Chem 2022; 243:114751. [DOI: 10.1016/j.ejmech.2022.114751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/22/2022] [Accepted: 09/04/2022] [Indexed: 11/25/2022]
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Lamba S, Roy A. DNA Topoisomerases in the Unicellular Protozoan Parasites: Unwinding the Mystery. Biochem Pharmacol 2022; 203:115158. [PMID: 35780829 DOI: 10.1016/j.bcp.2022.115158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/17/2022] [Accepted: 06/27/2022] [Indexed: 11/28/2022]
Abstract
DNA topoisomerases are a group of enzymes present ubiquitously in all organisms from unicellular protozoan parasites to humans. These enzymes control the topological problems caused by DNA double helix in the cell during nucleic acid metabolism. Certain types of topoisomerases present in unicellular parasites are quite different from human topoisomerases (hTop) concerning structure, expression, and function. Many protozoan parasites causing fatal diseases have DNA topoisomerases, which play vital roles in their survival. Given the fact that the structures of the protozoan parasite topoisomerases are different from humans, DNA topoisomerase acts as an essential target for potent drug development for parasitic diseases. Moreover, various studies revealed the therapeutic potential of these drugs targeting the parasitic topoisomerases. Therefore, the characterization of parasitic topoisomerases is pivotal for the development of future potential drug targets. Considering the importance of this ubiquitous enzyme as a potential drug target, we describe in detail all the reported protozoan topoisomerases in an organized manner including Leishmania, Trypanosoma, Plasmodium, Giardia, Entamoeba, Babesia, Theileria, Crithidia, Cryptosporidium, Toxoplasma, etc. This review highlights the unique attributes associated with the structure and function of different types of DNA topoisomerases from the unicellular protozoan parasites. So, it would be beneficial for researchers to obtain awareness about the currently characterized topoisomerases and the ones that need better characterization, understand the structure-function relationship of parasitic topoisomerases, to develop the potent anti-parasitic drugs, and also provides a future platform for therapeutic development.
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Affiliation(s)
- Swati Lamba
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune-411007, India
| | - Amit Roy
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune-411007, India.
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Selas A, Martin-Encinas E, Fuertes M, Masdeu C, Rubiales G, Palacios F, Alonso C. A patent review of topoisomerase I inhibitors (2016-present). Expert Opin Ther Pat 2021; 31:473-508. [PMID: 33475439 DOI: 10.1080/13543776.2021.1879051] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Topoisomerases are important targets for therapeutic improvement in the treatment of some diseases, including cancer. Inhibitors and poisons of topoisomerase I can limit the activity of this enzyme in its enzymatic cycle. This fact implies an anticancer effect of these drugs, since most cancer cells are characterized by both a higher activity of topoisomerase I and a higher replication rate compared to non-cancerous cells. Clinically approved inhibitors include camptothecin (CPT) and its derivatives. However, their limitations have encouraged different research groups to prepare new compounds, proof of which are the numerous research works and patents, some of them in the last five years. AREAS COVERED This review covers patent literature on topoisomerase I inhibitors and their application published between 2016-present. EXPERT OPINION The highest contribution toward patent development has been obtained from academics or small biotechnology companies. The most important fields of innovation include the preparation of prodrugs or inhibitors combined with other agents, as biocompatible polymers or antibodies. A promising development of topoisomerase I inhibitors is expected in the next years, directed to the treatment of diverse diseases, specifically toward different types of cancer and infectious diseases, among others.
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Affiliation(s)
- Asier Selas
- Departamento De Química Orgánica I, Facultad De Farmacia. Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Endika Martin-Encinas
- Departamento De Química Orgánica I, Facultad De Farmacia. Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Maria Fuertes
- Departamento De Química Orgánica I, Facultad De Farmacia. Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Carme Masdeu
- Departamento De Química Orgánica I, Facultad De Farmacia. Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Gloria Rubiales
- Departamento De Química Orgánica I, Facultad De Farmacia. Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Francisco Palacios
- Departamento De Química Orgánica I, Facultad De Farmacia. Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Concepción Alonso
- Departamento De Química Orgánica I, Facultad De Farmacia. Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Vitoria-Gasteiz, Spain
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da Silva Oliveira GL, da Silva APDSCL. Evaluation of the non-clinical toxicity of an antiparasitic agent: diminazene aceturate. Drug Chem Toxicol 2021; 45:2003-2013. [PMID: 33685320 DOI: 10.1080/01480545.2021.1894741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The diminazene aceturate (C14H15N7.2C4H7NO3) is a chemotherapeutic agent with more than six decades of use, however more studies regarding its toxicity still need to be performed. Thus, the present study determined the acute toxicity (14 days) of diminazene acetate (DIZE) in male and female swiss mice by changes in body mass, food consumption, biochemical and hematological parameters, locomotor activity and motor coordination. DIZE was administered at a single dose (1000 and 2000 mg/kg) orally. In addition, in vitro antioxidant capacity, hemolytic activity, toxicity in Artemia salina and in silico evaluation were also performed. The results obtained include several signs of toxicity (hypoactivity, loss of the straightening reflex and tachycardia), reduction of behavioral activity (locomotor activity and motor coordination) and significant changes (p < 0.05) in biochemical and hematological parameters. According to the in silico study, the DIZE can be classified based on the mean lethal dose (LD50) in category 4 (300 mg/kg < LD50 ≤ 2000 mg/kg, ProTox-II) or 3 (50 mg/kg < LD50 ≤ 300 mg/kg, AdmetSAR 1.0). Additionally, DIZE (30.3-969.9 nM) was not toxic to A. salina in the first 48 hours of treatment and was not cytotoxic to rat red blood cells after induced hemolysis. In vitro results indicated low antioxidant capacity against DPPH• and ABTS•+ radicals. Therefore, DIZE induces several adverse effects with influence on the central nervous system, changes in hematological and biochemical parameters and even mortality at the highest dose. However, absence of toxicity was observed in A. salina and rats red blood cells.
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Reguera RM, Elmahallawy EK, García-Estrada C, Carbajo-Andrés R, Balaña-Fouce R. DNA Topoisomerases of Leishmania Parasites; Druggable Targets for Drug Discovery. Curr Med Chem 2019; 26:5900-5923. [DOI: 10.2174/0929867325666180518074959] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/15/2018] [Accepted: 05/14/2018] [Indexed: 12/13/2022]
Abstract
DNA topoisomerases (Top) are a group of isomerase enzymes responsible for controlling the topological problems caused by DNA double helix in the cell during the processes of replication, transcription and recombination. Interestingly, these enzymes have been known since long to be key molecular machines in several cellular processes through overwinding or underwinding of DNA in all living organisms. Leishmania, a trypanosomatid parasite responsible for causing fatal diseases mostly in impoverished populations of low-income countries, has a set of six classes of Top enzymes. These are placed in the nucleus and the single mitochondrion and can be deadly targets of suitable drugs. Given the fact that there are clear differences in structure and expression between parasite and host enzymes, numerous studies have reported the therapeutic potential of Top inhibitors as antileishmanial drugs. In this regard, numerous compounds have been described as Top type IB and Top type II inhibitors in Leishmania parasites, such as camptothecin derivatives, indenoisoquinolines, indeno-1,5- naphthyridines, fluoroquinolones, anthracyclines and podophyllotoxins. The aim of this review is to highlight several facts about Top and Top inhibitors as potential antileishmanial drugs, which may represent a promising strategy for the control of this disease of public health importance.
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Affiliation(s)
- Rosa M. Reguera
- Department of Biomedical Sciences, University of Leon (ULE), Leon, Spain
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Pérez-Pertejo Y, Escudero-Martínez JM, Reguera RM, Balaña-Fouce R, García PA, Jambrina PG, San Feliciano A, Castro MÁ. Antileishmanial activity of terpenylquinones on Leishmania infantum and their effects on Leishmania topoisomerase IB. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2019; 11:70-79. [PMID: 31678841 PMCID: PMC6904838 DOI: 10.1016/j.ijpddr.2019.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/01/2019] [Accepted: 10/22/2019] [Indexed: 10/31/2022]
Abstract
Leishmania is the aethiological agent responsible for the visceral leishmaniasis, a serious parasite-borne disease widely spread all over the World. The emergence of resistant strains makes classical treatments less effective; therefore, new and better drugs are necessary. Naphthoquinones are interesting compounds for which many pharmacological properties have been described, including leishmanicidal activity. This work shows the antileishmanial effect of two series of terpenyl-1,4-naphthoquinones (NQ) and 1,4-anthraquinones (AQ) obtained from natural terpenoids, such as myrcene and myrceocommunic acid. They were evaluated both in vitro and ex vivo against the transgenic iRFP-Leishmania infantum strain and also tested on liver HepG2 cells to determine their selectivity indexes. The results indicated that NQ derivatives showed better antileishmanial activity than AQ analogues, and among them, compounds with a diacetylated hydroquinone moiety provided better results than their corresponding quinones. Regarding the terpenic precursor, compounds obtained from the monoterpenoid myrcene displayed good antiparasitic efficiency and low cytotoxicity for mammalian cells, whereas those derived from the diterpenoid showed better antileishmanial activity without selectivity. In order to explore their mechanism of action, all the compounds have been tested as potential inhibitors of Leishmania type IB DNA topoisomerases, but only some compounds that displayed the quinone ring were able to inhibit the recombinant enzyme in vitro. This fact together with the docking studies performed on LTopIB suggested the existence of another mechanism of action, alternative or complementary to LTopIB inhibition. In silico druglikeness and ADME evaluation of the best leishmanicidal compounds has shown good predictable druggability.
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Affiliation(s)
- Yolanda Pérez-Pertejo
- Departamento de Ciencias Biomédicas. Campus de Vegazana, University of León, León, Spain
| | | | - Rosa M Reguera
- Departamento de Ciencias Biomédicas. Campus de Vegazana, University of León, León, Spain
| | - Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas. Campus de Vegazana, University of León, León, Spain
| | - Pablo A García
- Departamento de Ciencias Farmacéuticas, Área de Química Farmacéutica, Facultad de Farmacia, CIETUS, IBSAL, Campus Miguel de Unamuno, University of Salamanca, Salamanca, Spain
| | - Pablo G Jambrina
- Departamento de Química Física. Facultad de Ciencias Químicas, University of Salamanca, Salamanca, Spain
| | - Arturo San Feliciano
- Departamento de Ciencias Farmacéuticas, Área de Química Farmacéutica, Facultad de Farmacia, CIETUS, IBSAL, Campus Miguel de Unamuno, University of Salamanca, Salamanca, Spain
| | - María-Ángeles Castro
- Departamento de Ciencias Farmacéuticas, Área de Química Farmacéutica, Facultad de Farmacia, CIETUS, IBSAL, Campus Miguel de Unamuno, University of Salamanca, Salamanca, Spain.
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Tejería A, Pérez-Pertejo Y, Reguera RM, Carbajo-Andrés R, Balaña-Fouce R, Alonso C, Martin-Encinas E, Selas A, Rubiales G, Palacios F. Antileishmanial activity of new hybrid tetrahydroquinoline and quinoline derivatives with phosphorus substituents. Eur J Med Chem 2018; 162:18-31. [PMID: 30408746 DOI: 10.1016/j.ejmech.2018.10.065] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/24/2018] [Accepted: 10/29/2018] [Indexed: 12/11/2022]
Abstract
Heterocyclic compounds, such as hybrid tetrahydroquinoline and quinoline derivatives with phosphorated groups, have been prepared by multicomponent cycloaddition reaction between phosphorus-substituted anilines, aldehydes and styrenes. The antileishmanial activity of these compounds has been evaluated on both promastigotes and intramacrophagic amastigotes of Leishmania infantum. Good antileishmanial activity of functionalized tetrahydroquinolines 4a, 5a, 6b and quinoline 8b has been observed with similar activity than the standard drug amphotericin B and close selective index (SI between 43 and 57) towards L. infantum amastigotes to amphotericin B. Special interest shows tetrahydroquinolylphosphine sulfide 5a with an EC50 value (0.61 ± 0.18 μM) similar to the standard drug amphotericin B (0.32 ± 0.05 μM) and selective index (SI = 56.87). In addition, compound 4c shows remarkable inhibition on Leishmania topoisomerase IB. Parallel theoretical study of stereoelectronic properties, application of docking-based virtual screening methods, along with molecular electrostatic potential and predictive druggability analyses are also reported.
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Affiliation(s)
- Ana Tejería
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Yolanda Pérez-Pertejo
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Rosa M Reguera
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Rubén Carbajo-Andrés
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Concepción Alonso
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain
| | - Endika Martin-Encinas
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain
| | - Asier Selas
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain
| | - Gloria Rubiales
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain
| | - Francisco Palacios
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain.
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Tejería A, Pérez-Pertejo Y, Reguera RM, Balaña-Fouce R, Alonso C, González M, Rubiales G, Palacios F. Substituted 1,5-naphthyridine derivatives as novel antileishmanial agents. Synthesis and biological evaluation. Eur J Med Chem 2018; 152:137-147. [PMID: 29704722 DOI: 10.1016/j.ejmech.2018.04.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/11/2018] [Accepted: 04/16/2018] [Indexed: 10/17/2022]
Abstract
Visceral leishmaniasis is a parasitic disease that affects, among other areas, both sides of the Mediterranean Basin. The drugs classically used in clinical practice are pentavalent antimonials (SbV) and amphotericin B, which are nephrotoxic, require parenteral administration, and increasing drug resistance in visceral leishmaniasis has been observed. These circumstances justify the search of new families of compounds to find effective drugs against the disease. Eukaryotic type I DNA topoisomerase (TopIB) has been found essential for the viability of the parasites, and therefore represents a promising target in the development of an antileishmanial therapy. In this search, heterocyclic compounds, such as 1,5-naphthyridines, have been prepared by cycloaddition reaction between N-(3-pyridyl)aldimines and acetylenes and their antileishmanial activity on promastigotes and amastigote-infected splenocytes of Leishmania infantum has been evaluated. In addition, the cytotoxic effects of newly synthesized compounds were assessed on host murine splenocytes in order to calculate the corresponding selective indexes (SI). Excellent antileishmanial activity of 1,5-naphthyridine 19, 21, 22, 24 and 27 has been observed with similar activity than the standard drug amphotericin B and higher selective index (SI > 100) towards L. infantum amastigotes than amphotericin B (SI > 62.5). Special interest shows the 1,5-naphthyridine 22 with an IC50 value (0.58 ± 0.03 μM) similar to the standard drug amphotericin B (0.32 ± 0.05 μM) and with the highest selective index (SI = 271.5). In addition, this compound shows remarkable inhibition on leishmanial TopIB. However, despite these interesting results, further studies are needed to disclose other potential targets involved in the antileishmanial effect of these novel compounds.
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Affiliation(s)
- Ana Tejería
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Yolanda Pérez-Pertejo
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Rosa M Reguera
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071, León, Spain
| | - Concepción Alonso
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain
| | - María González
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain
| | - Gloria Rubiales
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain
| | - Francisco Palacios
- Departamento de Química Orgánica I, Facultad de Farmacia and Centro de Investigación Lascaray (Lascaray Research Center), Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006, Vitoria-Gasteiz, Spain.
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Copper salisylaldoxime (CuSAL) imparts protective efficacy against visceral leishmaniasis by targeting Leishmania donovani topoisomerase IB. Exp Parasitol 2017; 175:8-20. [DOI: 10.1016/j.exppara.2017.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 01/11/2017] [Accepted: 02/03/2017] [Indexed: 10/20/2022]
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Tejería A, Pérez-Pertejo Y, Reguera RM, Balaña-Fouce R, Alonso C, Fuertes M, González M, Rubiales G, Palacios F. Antileishmanial effect of new indeno-1,5-naphthyridines, selective inhibitors of Leishmania infantum type IB DNA topoisomerase. Eur J Med Chem 2016; 124:740-749. [DOI: 10.1016/j.ejmech.2016.09.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/01/2016] [Accepted: 09/06/2016] [Indexed: 12/11/2022]
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Lacouth-Silva F, Xavier CV, da S. Setúbal S, Pontes AS, Nery NM, de Castro OB, Fernandes CFC, Honda ER, Zanchi FB, Calderon LA, Stábeli RG, Soares AM, Silva-Jardim I, Facundo VA, Zuliani JP. The effect of 3β, 6β, 16β-trihydroxylup-20(29)-ene lupane compound isolated from Combretum leprosum Mart. on peripheral blood mononuclear cells. Altern Ther Health Med 2015; 15:420. [PMID: 26608735 PMCID: PMC4659216 DOI: 10.1186/s12906-015-0948-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/21/2015] [Indexed: 01/11/2023]
Abstract
BACKGROUND The Combretum leprosum Mart. plant, popularly known as mofumbo, is used in folk medicine for inflammation, pain and treatment of wounds. From this species, it is possible to isolate three triterpenes: (3β, 6β, 16β-trihydroxylup-20(29)-ene) called lupane, arjunolic acid and molic acid. In this study, through preclinical tests, the effect of lupane was evaluated on the cytotoxicity and on the ability to activate cellular function by the production of TNF-α, an inflammatory cytokine, and IL-10, an immuno regulatory cytokine was assessed. The effect of lupane on the enzymes topoisomerase I and II was also evaluated. METHODS For this reason, peripheral blood mononuclear cells (PBMCs) were obtained and cytotoxicity was assessed by the MTT method at three different times (1, 15 and 24 h), and different concentrations of lupane (0.3, 0.7, 1.5, 6, 3 and 12 μg/mL). The cell function was assessed by the production of TNF-α and IL-10 by PBMCs quantified by specific enzyme immunoassay (ELISA). The activity of topoisomerases was assayed by in vitro biological assays and in silico molecular docking. RESULTS The results obtained showed that lupane at concentrations below 1.5 μg/mL was not toxic to the cells. Moreover, lupane was not able to activate cellular functions and did not alter the production of IL-10 and TNF-α. Furthermore, the data showed that lupane has neither interfered in the action of topoisomerase I nor in the action of topoisomerase II. CONCLUSION Based on preclinical results obtained in this study, we highlight that the compound studied (lupane) has moderate cytotoxicity, does not induce the production of TNF-α and IL-10, and does not act on human topoisomerases. Based on the results of this study and taking into consideration the reports about the anti-inflammatory and leishmanicidal activity of 3β, 6β, 16β-trihydroxylup-20(29)-ene, we suggest that this compound may serve as a biotechnological tool for the treatment of leishmaniasis in the future.
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Teles CBG, Moreira-Dill LS, Silva ADA, Facundo VA, de Azevedo WF, da Silva LHP, Motta MCM, Stábeli RG, Silva-Jardim I. A lupane-triterpene isolated from Combretum leprosum Mart. fruit extracts that interferes with the intracellular development of Leishmania (L.) amazonensis in vitro. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 15:165. [PMID: 26048712 PMCID: PMC4457080 DOI: 10.1186/s12906-015-0681-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 05/20/2015] [Indexed: 01/11/2023]
Abstract
BACKGROUND 3beta,6beta,16beta-trihydroxylup-20(29)-ene is a lupane triterpene isolated from Combretum leprosum fruit. The lupane group has been extensively used in studies on anticancer effects; however, its possible activity against protozoa parasites is yet poorly known. The high toxicity of the compounds currently used in leishmaniasis chemotherapy stimulates the investigation of new molecules and drug targets for antileishmanial therapy. METHODS The activity of 3beta,6beta,16beta-trihydroxylup-20(29)-ene was evaluated against Leishmania (L.) amazonensis by determining the cytotoxicity of the compound on murine peritoneal macrophages, as well as its effects on parasite survival inside host cells. To evaluate the effect of this compound on intracellular amastigotes, cultures of infected macrophages were treated for 24, 48 and 96 h and the percentage of infected macrophages and the number of intracellular parasites was scored using light microscopy. RESULTS Lupane showed significant activity against the intracellular amastigotes of L. (L.) amazonensis. The treatment with 109 μM for 96 h reduced in 80 % the survival index of parasites in BALB/c peritoneal macrophages. At this concentration, the triterpene caused no cytotoxic effects against mouse peritoneal macrophages. Ultrastructural analyses of L. (L.) amazonensis intracellular amastigotes showed that lupane induced some morphological changes in parasites, such as cytosolic vacuolization, lipid body formation and mitochondrial swelling. Bioinformatic analyses through molecular docking suggest that this lupane has high-affinity binding with DNA topoisomerase. CONCLUSION Taken together, our results have showed that the lupane triterpene from C. leprosum interferes with L. (L.) amazonensis amastigote replication and survival inside vertebrate host cells and bioinformatics analyses strongly indicate that this molecule may be a potential inhibitor of topoisomerase IB. Moreover, this study opens major prospects for the development of novel chemotherapeutic agents with leishmanicidal activity.
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Affiliation(s)
- Carolina Bioni Garcia Teles
- Malaria and Leishmaniasis Bioassays platform, Oswaldo Cruz Foundation (Fiocruz Rondônia), Porto Velho, Rondônia, Brazil.
| | - Leandro Soares Moreira-Dill
- Center of Studies for Biomolecules Applied to Health (CEBio), Oswaldo Cruz Foundation (Fiocruz Rondônia), Porto Velho, Rondônia, Brazil.
| | - Alexandre de Almeida Silva
- Laboratory of Insect Bioecology, Universidade Federal de Rondônia (UNIR), Porto Velho, Rondônia, Brazil.
- Laboratory of Medical Entomology, Oswaldo Cruz Foundation (Fiocruz Rondônia), Porto Velho, Rondônia, Brazil.
| | - Valdir Alves Facundo
- Research Laboratory of Chemistry of Natural Products, Universidade Federal de Rondônia (UNIR), Porto Velho, Rondônia, Brazil.
| | - Walter F de Azevedo
- Structural Biochemistry Laboratory, PUC, Rio Grande do Sul, Porto Alegre, Brazil.
| | - Luiz Hildebrando Pereira da Silva
- Laboratory of Molecular Epidemiology, Research Institute for Tropical Diseases in Rondônia (IPEPATRO), Porto Velho, Rondônia, Brazil.
| | - Maria Cristina M Motta
- Laboratory of Cellular Ultrastructure Hertha Meyer, Institute of Biophysics, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
| | - Rodrigo Guerino Stábeli
- Center of Studies for Biomolecules Applied to Health (CEBio), Oswaldo Cruz Foundation (Fiocruz Rondônia), Porto Velho, Rondônia, Brazil.
| | - Izaltina Silva-Jardim
- Department of Biological Sciences, Universidade Estadual de Santa Cruz (UESC), Ilheús, Bahia, Brazil.
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Balaña-Fouce R, Alvarez-Velilla R, Fernández-Prada C, García-Estrada C, Reguera RM. Trypanosomatids topoisomerase re-visited. New structural findings and role in drug discovery. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2014; 4:326-37. [PMID: 25516844 PMCID: PMC4266802 DOI: 10.1016/j.ijpddr.2014.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
There is an urgent need of new treatments against trypanosomatids-borne diseases. DNA topoisomerases are pointed as potential drug targets against unicellular parasites. Trypanosomatids have a full set of DNA topoisomerases in both nucleus and kinetoplast. TopII and TopIII are located in the kinetoplast and fully involved in kDNA replication. Tritryps TopIB differ in structure from mammalian’s pointing to an attractive target.
The Trypanosomatidae family, composed of unicellular parasites, causes severe vector-borne diseases that afflict human populations worldwide. Chagas disease, sleeping sickness, as well as different sorts of leishmaniases are amongst the most important infectious diseases produced by Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp., respectively. All these infections are closely related to weak health care services in low-income populations of less developed and least economically developed countries. Search for new therapeutic targets in order to hit these pathogens is of paramount priority, as no effective vaccine is currently in use against any of these parasites. Furthermore, present-day chemotherapy comprises old-fashioned drugs full of important side effects. Besides, they are prone to produce tolerance and resistance as a consequence of their continuous use for decades. DNA topoisomerases (Top) are ubiquitous enzymes responsible for solving the torsional tensions caused during replication and transcription processes, as well as in maintaining genomic stability during DNA recombination. As the inhibition of these enzymes produces cell arrest and triggers cell death, Top inhibitors are among the most effective and most widely used drugs in both cancer and antibacterial therapies. Top relaxation and decatenation activities, which are based on a common nicking–closing cycle involving one or both DNA strands, have been pointed as a promising drug target. Specific inhibitors that bind to the interface of DNA-Top complexes can stabilize Top-mediated transient DNA breaks. In addition, important structural differences have been found between Tops from the Trypanosomatidae family members and Tops from the host. Such dissimilarities make these proteins very interesting for drug design and molecular intervention. The present review is a critical update of the last findings regarding trypanosomatid’s Tops, their new structural features, their involvement both in the physiology and virulence of these parasites, as well as their use as promising targets for drug discovery.
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Affiliation(s)
- Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | - Raquel Alvarez-Velilla
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | | | - Carlos García-Estrada
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
| | - Rosa M Reguera
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
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Cortopassi WA, Penna-Coutinho J, Aguiar ACC, Pimentel AS, Buarque CD, Costa PRR, Alves BRM, França TCC, Krettli AU. Theoretical and experimental studies of new modified isoflavonoids as potential inhibitors of topoisomerase I from Plasmodium falciparum. PLoS One 2014; 9:e91191. [PMID: 24651068 PMCID: PMC3961230 DOI: 10.1371/journal.pone.0091191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 02/10/2014] [Indexed: 01/27/2023] Open
Abstract
DNA topoisomerase I from Plasmodium falciparum (PfTopoI), a potential selective target for chemotherapy and drug development against malaria, is used here, together with human Topo I (HssTopoI), for docking, molecular dynamics (MD) studies and experimental assays. Six synthetic isoflavonoid derivatives and the known PfTopoI inhibitors camptothecin and topotecan were evaluated in parallel. Theoretical results suggest that these compounds dock in the binding site of camptothecin and topotecan inside both enzymes and that LQB223 binds selectively in PfTopoI. In vitro tests against P. falciparum blood parasites corroborated the theoretical findings. The selectivity index (SI) of LQB223 ≥ 98 suggests that this molecule is the most promising in the group of compounds tested. In vivo experiments in mice infected with P. berghei showed that LQB223 has an antimalarial activity similar to that of chloroquine.
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Affiliation(s)
- Wilian A. Cortopassi
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Modelagem Aplicada a Defesa Química e Biológica, Instituto Militar de Engenharia, Rio de Janeiro, Brazil
| | - Julia Penna-Coutinho
- Laboratório de Malária, Centro de Pesquisas René Rachou, Fundação Instituto Oswaldo Cruz, Belo Horizonte, Brazil
- Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Anna C. C. Aguiar
- Laboratório de Malária, Centro de Pesquisas René Rachou, Fundação Instituto Oswaldo Cruz, Belo Horizonte, Brazil
- Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - André S. Pimentel
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Camilla D. Buarque
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paulo R. R. Costa
- Laboratório de Química Bioorgânica, Núcleo de Pesquisas de Produtos Naturais, Rio de Janeiro, Brazil
| | - Bruna R. M. Alves
- Departamento de Química, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tanos C. C. França
- Laboratório de Modelagem Aplicada a Defesa Química e Biológica, Instituto Militar de Engenharia, Rio de Janeiro, Brazil
| | - Antoniana U. Krettli
- Laboratório de Malária, Centro de Pesquisas René Rachou, Fundação Instituto Oswaldo Cruz, Belo Horizonte, Brazil
- Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Carballeira NM, Montano N, Alvarez-Velilla R, Prada CF, Reguera RM, Balaña-Fouce R. Synthesis of marine α-methoxylated fatty acid analogs that effectively inhibit the topoisomerase IB from Leishmania donovani with a mechanism different from that of camptothecin. Mar Drugs 2013; 11:3661-75. [PMID: 24084785 PMCID: PMC3826128 DOI: 10.3390/md11103661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/01/2013] [Accepted: 09/10/2013] [Indexed: 11/16/2022] Open
Abstract
Sponges biosynthesize α-methoxylated fatty acids with unusual biophysical and biological properties and in some cases they display enhanced anticancer activities. However, the antiprotozoal properties of the α-methoxylated fatty acids have been less studied. In this work, we describe the total synthesis of (5Z,9Z)-(±)-2-methoxy-5, 9-eicosadienoic acid (1) and its acetylenic analog (±)-2-methoxy-5,9-eicosadiynoic acid (2), and report that they inhibit (EC₅₀ values between 31 and 22 µM) the Leishmania donovani DNA topoisomerase IB enzyme (LdTopIB). The inhibition of LdTopIB (EC₅₀ = 53 µM) by the acid (±)-2-methoxy-6-icosynoic acid (12) was studied as well. The potency of LdTopIB inhibition followed the trend 2 > 1 > 12, indicating that the effectiveness of inhibition depends on the degree of unsaturation. All of the studied α-methoxylated fatty acids failed to inhibit the human topoisomerase IB enzyme (hTopIB) at 100 µM. However, the α-methoxylated fatty acids were capable of inhibiting an active but truncated LdTopIB with which camptothecin (CPT) cannot interact suggesting that the methoxylated fatty acids inhibit LdTopIB with a mechanism different from that of CPT. The diunsaturated fatty acids displayed low cytotoxicity towards Leishmania infantum promastigotes (EC₅₀ values between 260 and 240 µM), but 12 displayed a better cytotoxicity towards Leishmania donovani promastigotes (EC₅₀ = 100 µM) and a better therapeutic index.
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Affiliation(s)
- Néstor M. Carballeira
- Department of Chemistry, University of Puerto Rico, PO Box 23346, San Juan 00931-3346, Puerto Rico; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1809-787-764-0000 (ext. 4791); Fax: +1809-787-756-8242
| | - Nashbly Montano
- Department of Chemistry, University of Puerto Rico, PO Box 23346, San Juan 00931-3346, Puerto Rico; E-Mail:
| | - Raquel Alvarez-Velilla
- Department of Biomedical Sciences, University of León, Campus de Vegazana s/n, León 24071, Spain; E-Mails: (R.A.-V.); (R.M.R.); (R.B.-F.)
| | - Christopher F. Prada
- Infectious Diseases Research Center of the CHUL of Québec and Laval University, Québec City, Québec G1V 4G2, Canada; E-Mail:
| | - Rosa M. Reguera
- Department of Biomedical Sciences, University of León, Campus de Vegazana s/n, León 24071, Spain; E-Mails: (R.A.-V.); (R.M.R.); (R.B.-F.)
| | - Rafael Balaña-Fouce
- Department of Biomedical Sciences, University of León, Campus de Vegazana s/n, León 24071, Spain; E-Mails: (R.A.-V.); (R.M.R.); (R.B.-F.)
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Prada CF, Álvarez-Velilla R, Díaz-Gozález R, Pérez-Pertejo Y, Balaña-Fouce R, Reguera RM. Identification and characterization of the regions involved in the nuclear translocation of the heterodimeric leishmanial DNA topoisomerase IB. PLoS One 2013; 8:e73565. [PMID: 24023887 PMCID: PMC3759442 DOI: 10.1371/journal.pone.0073565] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/16/2013] [Indexed: 01/09/2023] Open
Abstract
Leishmania donovani, the causative organism for visceral leishmaniasis, contains a unique heterodimeric DNA-topoisomerase IB (LdTopIB). LdTopIB is a heterodimer made up of a large subunit and a small subunit that must interact with each other to build an active enzyme able to solve the topological tensions on the DNA. As LdTopIB is located within the nucleus, one or more nuclear localization signals (NLS) should exist to ensure its nuclear translocation. In this report three novel NLS have been identified through a sequential deletion study of the genes encoding of both subunits fused to that encoding the green fluorescent protein (GFP). NLS1 is a highly basic sequence of 43 amino acids in the C-terminal extension of the large protomer. We found two well-defined sequences in the small protomer: NLS2 is a 10-amino acid motif located in the N-terminal extension of the protein; NLS3 consists of a complex region of 28 amino acids placed in the vicinity of the catalytic Tyr-222 included at the conserved SKINY signature within the C-terminal. Furthermore, by means of yeast cell viability assays, conducted with several LdTopIB chimeras lacking any of the NLS motives, we have revealed that both subunits are transported independently to the nucleus. There was no evidence of LdTopIB accumulation in mitochondria or association to the kinetoplast DNA network. The results rule out the former hypothesis, which attributes nucleocytoplasmic transport of LdTopIB entirely to the large subunit. The LdTopIB is localized to the nucleus only.
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Affiliation(s)
- Christopher F. Prada
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana, León, Spain
| | - Raquel Álvarez-Velilla
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana, León, Spain
| | - Rosario Díaz-Gozález
- Instituto de Parasitología y Biomedicina "López-Neyra", Parque Tecnológico de Ciencias de la Salud, Granada, Spain
| | - Yolanda Pérez-Pertejo
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana, León, Spain
| | - Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana, León, Spain
- * E-mail:
| | - Rosa M. Reguera
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana, León, Spain
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18
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Carballeira NM. Recent developments in the antiprotozoal and anticancer activities of the 2-alkynoic fatty acids. Chem Phys Lipids 2013; 172-173:58-66. [PMID: 23727443 DOI: 10.1016/j.chemphyslip.2013.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/03/2013] [Accepted: 05/06/2013] [Indexed: 12/21/2022]
Abstract
The 2-alkynoic fatty acids are an interesting group of synthetic compounds that display antimycobacterial, antifungal, anticancer, and pesticidal activities but their antiprotozoal activity has received little attention until recently. In this review we have summarized our present knowledge of the biomedical potential of the 2-hexadecynoic acid (2-HDA) and 2-octadecynoic acid (2-ODA) together with several mechanistic pieces of work attesting to the fact that these compounds, and their metabolites, are good fatty acid biosynthesis inhibitors. The antiprotozoal activity of 2-HDA and 2-ODA against Leishmania donovani and Plasmodium falciparum, parasites responsible for visceral leishmaniasis and malaria, respectively, is also reviewed. The evidence obtained so far supports the fact that these fatty acids are good inhibitors of the L. donovani DNA topoisomerase IB enzyme (LdTopIB) and the potency of LdTopIB inhibition is chain length dependent. We also demonstrate the generality of the antiprotozoal activity of 2-HDA and 2-ODA against P. falciparum, and review our present knowledge of their inhibition of key P. falciparum enzymes such as PfFabZ, PfFabG, and PfFabI together with some possible modes of inhibition. Recent research by our group has also demonstrated that 2-ODA displays antineoplastic activity, specifically against the neuroblastoma SH-SY5Y cell line via lactate dehydrogenase (LDH) release, which is a cell death mechanism principally associated to necrosis. This is the first comprehensive review of the medicinal chemistry of this interesting group of acetylenic fatty acids.
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Affiliation(s)
- Néstor M Carballeira
- Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, PO Box 23346, San Juan 00931-3346, Puerto Rico.
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Prada CF, Alvarez-Velilla R, Balaña-Fouce R, Prieto C, Calvo-Álvarez E, Escudero-Martínez JM, Requena JM, Ordóñez C, Desideri A, Pérez-Pertejo Y, Reguera RM. Gimatecan and other camptothecin derivatives poison Leishmania DNA-topoisomerase IB leading to a strong leishmanicidal effect. Biochem Pharmacol 2013; 85:1433-40. [PMID: 23466420 DOI: 10.1016/j.bcp.2013.02.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 02/22/2013] [Accepted: 02/22/2013] [Indexed: 11/30/2022]
Abstract
The aim of this work is the in vitro and ex vivo assessment of the leishmanicidal activity of camptothecin and three analogues used in cancer therapy: topotecan (Hycantim®), gimatecan (ST1481) and the pro-drug irinotecan (Camptosar®) as well as its active metabolite SN-38 against Leishmania infantum. The activity of camptothecin and its derivatives was studied on extracellular L. infantum infrared-emitting promastigotes and on an ex vivo murine model of infected splenocytes with L. infantum fluorescent amastigotes. In situ formation of SDS/KCl precipitable DNA-protein complexes in Leishmania promastigotes indicated that these drugs are DNA topoisomerase IB poisons. The inhibitory potency of camptothecin derivatives on recombinant L. infantum topoisomerase IB was assessed in vitro showing that gimatecan is the most active compound preventing the relaxation of supercoiled DNA at submicromolar concentrations. Cleavage equilibrium assays in Leishmania topoisomerase IB show that gimatecan changes the equilibrium towards cleavage at much lower concentrations than the other camptothecin derivatives and that this effect persists over time. Gimatecan and camptothecin were the most powerful compounds preventing cell growth of free-living L. infantum promastigotes within the same concentration range. All these compounds killed L. infantum splenocyte-infecting amastigotes within the nanomolar range. The amastigote form showed higher sensitivity to topoisomerase IB poisons (with high therapeutic selectivity indexes) than free-living promastigotes. All the compounds assayed poisoned L. infantum DNA topoisomerase IB leading to a strong leishmanicidal effect. Camptothecin derivatives are suitable for reducing the parasitic burden of ex vivo infected splenocytes. The selectivity index of gimatecan makes it a promising drug against this neglected disease.
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Affiliation(s)
- Christopher F Prada
- Departamento de Ciencias Biomédicas, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
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Juul S, Nielsen CJF, Labouriau R, Roy A, Tesauro C, Jensen PW, Harmsen C, Kristoffersen EL, Chiu YL, Frøhlich R, Fiorani P, Cox-Singh J, Tordrup D, Koch J, Bienvenu AL, Desideri A, Picot S, Petersen E, Leong KW, Ho YP, Stougaard M, Knudsen BR. Droplet microfluidics platform for highly sensitive and quantitative detection of malaria-causing Plasmodium parasites based on enzyme activity measurement. ACS NANO 2012; 6:10676-83. [PMID: 23121492 PMCID: PMC3528816 DOI: 10.1021/nn3038594] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present an attractive new system for the specific and sensitive detection of the malaria-causing Plasmodium parasites. The system relies on isothermal conversion of single DNA cleavage-ligation events catalyzed specifically by the Plasmodium enzyme topoisomerase I to micrometer-sized products detectable at the single-molecule level. Combined with a droplet microfluidics lab-on-a-chip platform, this design allowed for sensitive, specific, and quantitative detection of all human-malaria-causing Plasmodium species in single drops of unprocessed blood with a detection limit of less than one parasite/μL. Moreover, the setup allowed for detection of Plasmodium parasites in noninvasive saliva samples from infected patients. During recent years malaria transmission has declined worldwide, and with this the number of patients with low-parasite density has increased. Consequently, the need for accurate detection of even a few parasites is becoming increasingly important for the continued combat against the disease. We believe that the presented droplet microfluidics platform, which has a high potential for adaptation to point-of-care setups suitable for low-resource settings, may contribute significantly to meet this demand. Moreover, potential future adaptation of the presented setup for the detection of other microorganisms may form the basis for the development of a more generic platform for diagnosis, fresh water or food quality control, or other purposes within applied or basic science.
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Affiliation(s)
- Sissel Juul
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | | | - Rodrigo Labouriau
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Amit Roy
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Cinzia Tesauro
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Pia W. Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Charlotte Harmsen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | | | - Ya-Ling Chiu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Rikke Frøhlich
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Paola Fiorani
- Institute of Translational Pharmacology, National Research Council, CNR, Rome, Italy
| | - Janet Cox-Singh
- School of Medicine, University of St Andrews, Fife KY16 9TF, Scotland and The Malaria Research Centre, University Malaysia Sarawak, Kuching, Sarawak, Malaysia
| | - David Tordrup
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | - Jørn Koch
- Department of Pathology, Aarhus University Hospital, Denmark
| | - Anne-Lise Bienvenu
- Malaria Research Unit, SMITH, ICBMS, UMR CNRS 5246, University Lyon1, and Hospices civils de Lyon, Lyon, France
| | - Alessandro Desideri
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Stephane Picot
- Malaria Research Unit, SMITH, ICBMS, UMR CNRS 5246, University Lyon1, and Hospices civils de Lyon, Lyon, France
| | - Eskild Petersen
- Department of Infectious Diseases, Institute of Clinical Medicine, Aarhus University Hospital-Skejby, Denmark
| | - Kam W. Leong
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Yi-Ping Ho
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark
| | - Magnus Stougaard
- Department of Pathology, Aarhus University Hospital, Denmark
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark
| | - Birgitta R. Knudsen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark
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A pentapeptide signature motif plays a pivotal role in Leishmania DNA topoisomerase IB activity and camptothecin sensitivity. Biochim Biophys Acta Gen Subj 2012; 1820:2062-71. [DOI: 10.1016/j.bbagen.2012.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/03/2012] [Accepted: 09/07/2012] [Indexed: 01/07/2023]
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22
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Carballeira NM, Cartagena M, Sanabria D, Tasdemir D, Prada CF, Reguera RM, Balaña-Fouce R. 2-Alkynoic fatty acids inhibit topoisomerase IB from Leishmania donovani. Bioorg Med Chem Lett 2012; 22:6185-9. [PMID: 22932312 DOI: 10.1016/j.bmcl.2012.08.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 07/20/2012] [Accepted: 08/01/2012] [Indexed: 10/28/2022]
Abstract
2-Alkynoic fatty acids display antimycobacterial, antifungal, and pesticidal activities but their antiprotozoal activity has received little attention. In this work we synthesized the 2-octadecynoic acid (2-ODA), 2-hexadecynoic acid (2-HDA), and 2-tetradecynoic acid (2-TDA) and show that 2-ODA is the best inhibitor of the Leishmania donovani DNA topoisomerase IB enzyme (LdTopIB) with an EC(50)=5.3±0.7μM. The potency of LdTopIB inhibition follows the trend 2-ODA>2-HDA>2-TDA, indicating that the effectiveness of inhibition depends on the fatty acid carbon chain length. All of the studied 2-alkynoic fatty acids were less potent inhibitors of the human topoisomerase IB enzyme (hTopIB) as compared to LdTopIB. 2-ODA also displayed in vitro activity against Leishmania donovani (IC(50)=11.0μM), but it was less effective against other protozoa, Trypanosoma cruzi (IC(50)=48.1μM) and Trypanosoma brucei rhodesiense (IC(50)=64.5μM). The antiprotozoal activity of the 2-alkynoic fatty acids, in general, followed the trend 2-ODA>2-HDA>2-TDA. The experimental information gathered so far indicates that 2-ODA is a promising antileishmanial compound.
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Affiliation(s)
- Néstor M Carballeira
- Department of Chemistry, University of Puerto Rico, PO Box 23346, San Juan 00931-3346, Puerto Rico.
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Mitochondria and Trypanosomatids: Targets and Drugs. Pharm Res 2011; 28:2758-70. [DOI: 10.1007/s11095-011-0586-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 09/07/2011] [Indexed: 01/20/2023]
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Roy A, D'Annessa I, Nielsen CJF, Tordrup D, Laursen RR, Knudsen BR, Desideri A, Andersen FF. Peptide Inhibition of Topoisomerase IB from Plasmodium falciparum. Mol Biol Int 2011; 2011:854626. [PMID: 22091414 PMCID: PMC3200115 DOI: 10.4061/2011/854626] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 03/03/2011] [Indexed: 11/21/2022] Open
Abstract
Control of diseases inflicted by protozoan parasites such as Leishmania, Trypanosoma, and Plasmodium, which pose a serious threat to human health worldwide, depends on a rather small number of antiparasite drugs, of which many are toxic and/or inefficient. Moreover, the increasing occurrence of drug-resistant parasites emphasizes the need for new and effective antiprotozoan drugs. In the current study, we describe a synthetic peptide, WRWYCRCK, with inhibitory effect on the essential enzyme topoisomerase I from the malaria-causing parasite Plasmodium falciparum. The peptide inhibits specifically the transition from noncovalent to covalent DNA binding of P. falciparum topoisomerase I, while it does not affect the ligation step of catalysis. A mechanistic explanation for this inhibition is provided by molecular docking analyses. Taken together the presented results suggest that synthetic peptides may represent a new class of potential antiprotozoan drugs.
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Affiliation(s)
- Amit Roy
- Department of Molecular Biology and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
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Wainwright M. Dyes, trypanosomiasis and DNA: a historical and critical review. Biotech Histochem 2010; 85:341-54. [DOI: 10.3109/10520290903297528] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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García-Estrada C, Prada CF, Fernández-Rubio C, Rojo-Vázquez F, Balaña-Fouce R. DNA topoisomerases in apicomplexan parasites: promising targets for drug discovery. Proc Biol Sci 2010; 277:1777-87. [PMID: 20200034 DOI: 10.1098/rspb.2009.2176] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The phylum Apicomplexa includes a large group of protozoan parasites responsible for a wide range of animal and human diseases. Destructive pathogens, such as Plasmodium falciparum and Plasmodium vivax, causative agents of human malaria, Cryptosporidium parvum, responsible of childhood diarrhoea, and Toxoplasma gondii, responsible for miscarriages and abortions in humans, are frequently associated with HIV immunosuppression in AIDS patients. The lack of effective vaccines, along with years of increasing pressure to eradicate outbreaks with the use of drugs, has favoured the formation of multi-drug resistant strains in endemic areas. Almost all apicomplexan of medical interest contain two endosymbiotic organelles that contain their own mitochondrial and apicoplast DNA. Apicoplast is an attractive target for drug testing because in addition to harbouring singular metabolic pathways absent in the host, it also has its own transcription and translation machinery of bacterial origin. Accordingly, apicomplexan protozoa contain an interesting mixture of enzymes to unwind DNA from eukaryotic and prokaryotic origins. On the one hand, the main mechanism of DNA unwinding includes the scission of one-type I-or both DNA strands-type II eukaryotic topoisomerases, establishing transient covalent bonds with the scissile end. These enzymes are targeted by camptothecin and etoposide, respectively, two natural drugs whose semisynthetic derivatives are currently used in cancer chemotherapy. On the other hand, DNA gyrase is a bacterial-borne type II DNA topoisomerase that operates within the apicoplast and is effectively targeted by bacterial antibiotics like fluoroquinolones and aminocoumarins. The present review is an update on the new findings concerning topoisomerases in apicomplexan parasites and the role of these enzymes as targets for therapeutic agents.
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Affiliation(s)
- Carlos García-Estrada
- Departamento de Ciencias Biomédicas (INTOXCAL), Universidad de León, , Campus de Vegazana s/n, León, Spain
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Poorrajab F, Ardestani SK, Foroumadi A, Emami S, Kariminia A, Behrouzi-Fardmoghadam M, Shafiee A. Selective leishmanicidal effect of 1,3,4-thiadiazole derivatives and possible mechanism of action against Leishmania species. Exp Parasitol 2009; 121:323-30. [DOI: 10.1016/j.exppara.2008.12.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 12/03/2008] [Accepted: 12/05/2008] [Indexed: 11/29/2022]
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Turabekova MA, Vinogradova VI, Rasulev BF, Levkovich MG, Werbovetz K, Capers J, Abdullaev ND. Antiparasitic activity of certain isoquinoline alkaloids and their hypothetical complexes with oligonucleotides. Chem Nat Compd 2008. [DOI: 10.1007/s10600-008-9057-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Balaña-Fouce R, García-Estrada C, Pérez-Pertejo Y, Reguera RM. Gene disruption of the DNA topoisomerase IB small subunit induces a non-viable phenotype in the hemoflagellate Leishmania major. BMC Microbiol 2008; 8:113. [PMID: 18611247 PMCID: PMC2492870 DOI: 10.1186/1471-2180-8-113] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 07/08/2008] [Indexed: 11/24/2022] Open
Abstract
Background The unusual heterodimeric leishmanial DNA topoisomerase IB consists of a large subunit containing the phylogenetically conserved "core" domain, and a small subunit harboring the C-terminal region with the characteristic tyrosine residue in the active site. RNAi silencing of any of both protomers induces a non-viable phenotype in the hemoflagelate Trypanosoma brucei. Unfortunately, this approach is not suitable in Leishmania where gene replacement with an antibiotic marker is the only approach to generate lack-of-function mutants. In this work, we have successfully generated null mutants in the small subunit of the L. major DNA topoisomerase IB using two selection markers, each conferring resistance to hygromycin B and puromycin, respectively. Results We have successfully replaced both topS loci with two selection markers. However, to achieve the second transfection round, we have had to rescue the null-homozygous with an episomal vector carrying the Leishmania major topS gene. Phenotypic characterization of the L. major rescued strain and a L. major strain, which co-overexpresses both subunits, shows few differences in DNA relaxation and camptothecin cytotoxicity when it was compared to the wild-type strain. Studies on phosphatidylserine externalization show a poor incidence of camptothecin-induced programmed cell death in L. major, but an effective cell-cycle arrest occurs within the first 24 h. S-Phase delay and G2/M reversible arrest was the main outcome at lower concentrations, but irreversible G2 arrest was detected at higher camptothecin pressure. Conclusion Results obtained in this work evidence the essentiality of the topS gene encoding the L. major DNA topoisomerase IB small subunit. Reversibility of the camptothecin effect points to the existence of effective checkpoint mechanisms in Leishmania parasites.
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Affiliation(s)
- Rafael Balaña-Fouce
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, Campus de Vegazana s/n; 24071 León, Spain.
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Mutational study of the "catalytic tetrad" of DNA topoisomerase IB from the hemoflagellate Leishmania donovani: Role of Asp-353 and Asn-221 in camptothecin resistance. Biochem Pharmacol 2008; 76:608-19. [PMID: 18655776 DOI: 10.1016/j.bcp.2008.06.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 06/22/2008] [Accepted: 06/24/2008] [Indexed: 11/21/2022]
Abstract
Leishmania donovani, the causative organism for visceral leishmaniasis, contains a unique bisubunit DNA-topoisomerase IB (LdTopIB). The catalytically active enzyme is a heterodimer constituted by a large subunit (LdTopIL) containing a non-conserved N-terminal end and the phylogenetically conserved core domain, whereas the small subunit (LdTopIS) harbors the C-terminal domain with the characteristic tyrosine residue in the active site. Site-directed mutagenesis was used to substitute the basic amino acid (Arg-314, Lys-352, Arg-410 and His-453) of the LdTopIL subunit by the neutral amino acid alanine. The expression of these mutants in a topoisomerase-free yeast strain produced inactive proteins. Similarly, when the Tyr-222 from small subunit, involved in DNA cleavage, was substituted by Phe no topoisomerase activity was detected in yeast overexpressing extracts. In addition two substitutions involved in camptothecin inhibition were also analyzed. Asp-353 located in the core domain of the large subunit and Asn-221 which heads Tyr-222 in the small subunit, were replaced by Ala and Ser, respectively. These mutants were insensitive to the inhibitor; despite they displayed significant relaxation activity.
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Abstract
São apresentados conceitos básicos sobre célula, código genético e síntese protéica, e sobre algumas técnicas de biologia molecular, tais como PCR, PCR-RFLP, seqüenciamento de DNA, RT-PCR e immunoblotting. São fornecidos protocolos de extração de nucleotídeos e de proteínas, como salting out no sangue periférico e métodos do fenol-clorofórmio e do trizol em tecidos. Seguem-se exemplos comentados da aplicação de técnicas de biologia molecular para o diagnóstico etiológico e pesquisa em dermatoses tropicais, com ênfase na leishmaniose tegumentar americana e hanseníase.
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Díaz González R, Pérez Pertejo Y, Redondo CM, Pommier Y, Balaña-Fouce R, Reguera RM. Structural insights on the small subunit of DNA topoisomerase I from the unicellular parasite Leishmania donovani. Biochimie 2007; 89:1517-27. [PMID: 17900785 DOI: 10.1016/j.biochi.2007.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Accepted: 07/20/2007] [Indexed: 11/28/2022]
Abstract
Leishmania donovani, the causative organism of visceral leishmaniasis, contains a unique heterodimeric DNA topoisomerase IB (LdTop1). The catalytically active enzyme consists of a large subunit (LdTop1L), which contains the non-conserved N-terminal end and a phylogenetically conserved core domain, and of a small subunit (LdTop1S) which harbours the C-terminal region with a characteristic tyrosine residue in the active site. Heterologous co-expression of LdTop1L and LdTop1S in a topoisomerase I deficient yeast strain, reconstitutes a fully functional enzyme which can be used for structural studies. The role played by the non-conserved N-terminal extension of LdTop1S in both relaxation activity and CPT sensitivity of LdTop1 has been examined co-expressing the full-length LdTop1L with several deletions of LdTop1S lacking growing sequences of the N-terminal end. The sequential deletion study shows that the first 174 amino acids of LdTop1S are dispensable in terms of relaxation activity and DNA cleavage. It is also described that the trapping of the covalent complex between LdTop1 and DNA by CPT requires a pentapeptide between amino acid residues 175 and 179 of LdTop1S. Our results suggest the crucial role played by the N-terminal extension of the small subunit of DNA topoisomerase I.
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Affiliation(s)
- Rosario Díaz González
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, Campus de Vegazana s/n; 24071 León, Spain
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Díaz González R, Pérez Pertejo Y, Ordóñez D, Balaña-Fouce R, Reguera RM. Deletion study of DNA topoisomerase IB from Leishmania donovani: searching for a minimal functional heterodimer. PLoS One 2007; 2:e1177. [PMID: 18000548 PMCID: PMC2063514 DOI: 10.1371/journal.pone.0001177] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 10/26/2007] [Indexed: 11/25/2022] Open
Abstract
The substantial differences between trypanosomal and leishmanial DNA topoisomerase IB concerning to their homologues in mammals have provided a new lead in the study of the structural determinants that can be effectively targeted. Leishmania donovani, the causative agent of visceral leishmaniasis, contains an unusual heterodimeric DNA topoisomerase IB. The catalytically active enzyme consists of a large subunit (LdTopIL), which contains the non-conserved N-terminal end and the phylogenetically conserved “core” domain, and of a small subunit (LdTopIS) which harbors the C-terminal region with the characteristic tyrosine residue in the active site. Heterologous co-expression of LdTopIL and LdTopIS genes in a topoisomerase I deficient yeast strain, reconstitutes a fully functional enzyme LdTopIL/S which can be used for structural studies. An approach by combinatorial cloning of deleted genes encoding for truncated versions of both subunits was used in order to find out structural insights involved in enzyme activity or protein-protein interaction. The role played by the non-conserved N-terminal extension of LdTopIL in both relaxation activity and CPT sensitivity has been examined co-expressing the full-length LdTopIS and a fully active LdTopIΔS deletion with several deletions of LdTopIL lacking growing sequences of the N-terminal end. The sequential deletion study shows that the first 26 amino acids placed at the N-terminal end and a variable region comprised between Ala548 to end of the C-terminal extension of LdTopIL were enzymatically dispensable. Altogether this combinatorial approach provides important structural insights of the regions involved in relaxation activity and for understanding the atypical structure of this heterodimeric enzyme.
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Affiliation(s)
- Rosario Díaz González
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, León, Spain
| | - Yolanda Pérez Pertejo
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, León, Spain
| | - David Ordóñez
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, León, Spain
| | - Rafael Balaña-Fouce
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, León, Spain
- * To whom correspondence should be addressed. E-mail:
| | - Rosa M. Reguera
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, León, Spain
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Cortés F, Pastor N, Mateos S, Domínguez I. Topoisomerase inhibitors as therapeutic weapons. Expert Opin Ther Pat 2007. [DOI: 10.1517/13543776.17.5.521] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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