1
|
Reed EK, Smith KA. Using our understanding of interactions between helminth metabolism and host immunity to target worm survival. Trends Parasitol 2024; 40:549-561. [PMID: 38853079 DOI: 10.1016/j.pt.2024.05.006] [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: 01/29/2024] [Revised: 05/10/2024] [Accepted: 05/12/2024] [Indexed: 06/11/2024]
Abstract
Helminths can adapt to environmental conditions in the host, utilising anaerobic processes like fermentation and malate dismutation to produce energy from carbohydrate. Although targeting carbohydrate metabolism is an established therapeutic strategy to combat helminth infection, questions remain over the metabolic pathways they employ as adults to survive and evade host immunity. Helminths also use amino acid, polyunsaturated fatty acid (PUFA), and cholesterol metabolism, a possible strategy favouring the production of immunomodulatory compounds that may influence survival in the host. Here, we discuss the significance of these differing metabolic pathways and whether targeting of helminth metabolic pathways may allow for the development of novel anthelmintics.
Collapse
Affiliation(s)
- Ella K Reed
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | | |
Collapse
|
2
|
Carey SM, O’Neill DM, Conner GB, Sherman J, Rodriguez A, D’Antonio EL. Discovery of Strong 3-Nitro-2-Phenyl- 2H-Chromene Analogues as Antitrypanosomal Agents and Inhibitors of Trypanosoma cruzi Glucokinase. Int J Mol Sci 2024; 25:4319. [PMID: 38673904 PMCID: PMC11050443 DOI: 10.3390/ijms25084319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Chagas disease is one of the world's neglected tropical diseases, caused by the human pathogenic protozoan parasite Trypanosoma cruzi. There is currently a lack of effective and tolerable clinically available therapeutics to treat this life-threatening illness and the discovery of modern alternative options is an urgent matter. T. cruzi glucokinase (TcGlcK) is a potential drug target because its product, d-glucose-6-phosphate, serves as a key metabolite in the pentose phosphate pathway, glycolysis, and gluconeogenesis. In 2019, we identified a novel cluster of TcGlcK inhibitors that also exhibited anti-T. cruzi efficacy called the 3-nitro-2-phenyl-2H-chromene analogues. This was achieved by performing a target-based high-throughput screening (HTS) campaign of 13,040 compounds. The selection criteria were based on first determining which compounds strongly inhibited TcGlcK in a primary screen, followed by establishing on-target confirmed hits from a confirmatory assay. Compounds that exhibited notable in vitro trypanocidal activity over the T. cruzi infective form (trypomastigotes and intracellular amastigotes) co-cultured in NIH-3T3 mammalian host cells, as well as having revealed low NIH-3T3 cytotoxicity, were further considered. Compounds GLK2-003 and GLK2-004 were determined to inhibit TcGlcK quite well with IC50 values of 6.1 µM and 4.8 µM, respectively. Illuminated by these findings, we herein screened a small compound library consisting of thirteen commercially available 3-nitro-2-phenyl-2H-chromene analogues, two of which were GLK2-003 and GLK2-004 (compounds 1 and 9, respectively). Twelve of these compounds had a one-point change from the chemical structure of GLK2-003. The analogues were run through a similar primary screening and confirmatory assay protocol to our previous HTS campaign. Subsequently, three in vitro biological assays were performed where compounds were screened against (a) T. cruzi (Tulahuen strain) infective form co-cultured within NIH-3T3 cells, (b) T. brucei brucei (427 strain) bloodstream form, and (c) NIH-3T3 host cells alone. We report on the TcGlcK inhibitor constant determinations, mode of enzyme inhibition, in vitro antitrypanosomal IC50 determinations, and an assessment of structure-activity relationships. Our results reveal that the 3-nitro-2-phenyl-2H-chromene scaffold holds promise and can be further optimized for both Chagas disease and human African trypanosomiasis early-stage drug discovery research.
Collapse
Affiliation(s)
- Shane M. Carey
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, SC 29909, USA
| | - Destiny M. O’Neill
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, SC 29909, USA
| | - Garrett B. Conner
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, SC 29909, USA
| | - Julian Sherman
- Department of Microbiology, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA (A.R.)
| | - Ana Rodriguez
- Department of Microbiology, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA (A.R.)
| | - Edward L. D’Antonio
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, SC 29909, USA
| |
Collapse
|
3
|
Mlozen MM, Van Marwijk J, Wilhelmi BS, Whiteley C. Comparative Analysis of the Interaction of Silver Nanoparticles with Hexokinase from Trypanosoma brucei and Humans. Int J Nanomedicine 2023; 18:1399-1411. [PMID: 36992823 PMCID: PMC10041994 DOI: 10.2147/ijn.s401319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 03/14/2023] [Indexed: 03/31/2023] Open
Abstract
Background Regardless of the efforts to ease cases of human African trypanosomiasis (HAT), an increased number of cases get reported annually. This is because of drug resistant Trypanosoma brucei (Tb), the causative agent of the illness. This has renewed the need for creative methods to find new anti-trypanosomal drugs. The blood stream form (BSF) of the parasite depends exclusively on the glycolytic pathway for energy production while it is in the human host. Interruptions in this pathway efficiently kills the parasite. Trypanosoma brucei hexokinase (TbHK) is the first enzyme in glycolysis, and any effectors or inhibitors of TbHK would have potential as anti-trypanosomal agents. Methods TbHK and human glucokinase (hGCK) were over-expressed with a 6 histidine-tag in E. coli BL21(DE3) cells having the pRARE2 plasmid. Results TbHK had thermal and pH stability between 30°C and 55°C and 7.5 and 8.5, respectively, while hGCK exhibited thermal and pH stability between 30°C and 40°C and 7.0 and 8.0, respectively. Kinetically, TbHK had a Km of 39.3 µM, Vmax of 0.066 µmol.min-1.mL-1, kcat of 2.05 min-1 and kcat/Km of 0.0526 min-1.µmol-1. hGCK exhibited a Km of 4.5 µM, Vmax of 0.032 µnmol.min-1.mL-1, kcat of 11.25 min-1, and kcat/Km of 2.5 min-1.µmol-1. Interaction kinetic studies of silver nanoparticles (AgNPs) (0.1 µM) of average size of 6 nm with TbHK and hGCK were conducted. AgNPs selectively inhibited TbHK over hGCK. TbHK showed a non-competitive inhibition with a 50% and 28% decrease in Vmax, and kcat/km, respectively. HsGCK showed a 33% increase in affinity, 9% decrease in Vmax, and a 50% increase in enzyme efficiency. Conclusion The observed pattern of hGCK and AgNPs falls under the uncompetitive inhibition. The observed highly selective inhibitory effects of AgNPs between TbHK and hGCK may be used in development of new anti-trypanosomal drugs.
Collapse
Affiliation(s)
- Madalitso M Mlozen
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda (Grahamstown), South Africa
- Malawi Adventist University, Malamulo Campus, Department of Biomedical Sciences, Makwasa, Malawi
- Correspondence: Madalitso M Mlozen, Malawi Adventist University, Malamulo campus, Department of Biomedical Sciences, P.O.Box 55, Makwasa, Tel +265 884628334, Email
| | - Jacqueline Van Marwijk
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda (Grahamstown), South Africa
| | - Brendan Shane Wilhelmi
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda (Grahamstown), South Africa
| | - Chris Whiteley
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda (Grahamstown), South Africa
| |
Collapse
|
4
|
Gene expression study to elucidate the anti-trypanosomal activity of quinapyramine methyl sulphate (QPS). Parasitol Int 2022; 91:102632. [PMID: 35870741 DOI: 10.1016/j.parint.2022.102632] [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: 04/11/2022] [Revised: 07/12/2022] [Accepted: 07/17/2022] [Indexed: 11/22/2022]
Abstract
The kinetoplastid protozoan parasite, Trypanosoma evansi causes a fatal disease condition known as Surra in equines throughout the globe. Disease condition being acute in nature, entrust a huge economic and health impact on the equine industry. Till date, quinapyramine methyl sulphate (QPS) is the first line of treatment and a panacea for the T. evansi infection in equines. Still after the >70 years of its discovery, there is no clue about the mode of action of QPS in T. evansi. The establishment of in vitro cultivation of T. evansi in HMI-9 media has provided opportunity to study the alteration in mRNA expression of parasite on exposure to the drug. With this research gap, the present study aimed to investigate the relative mRNA expression of 13 important drug target genes to elucidate the anti-trypanosomal activity of QPS against T. evansi. The IC50 of QPS against a pony isolate of T. evansi was determined as 276.4 nM(147.21 ng/ mL) in the growth inhibitory assay. The in vitro cultured T. evansi population were further exposed to IC50 of QPS and their relative mRNA expression was studied at 12 h, 24 h and 48 h interval.The mRNA expression of several genes such as hexokinase, trypanothione reductase, aurora kinase, oligopeptidase B and ribonucleotide reductase II were found refractory (non-significant, p > 0.1234) to the exposure of QPS. Significant up-regulation of trans-sialidase (p < 0.0001), ESAG8 (p < 0.0021), ribonucleotide reductase I (p < 0.0001), ornithine decarboxylase (p < 0.0001), topoisomerase II (p < 0.0021) and casein kinase I (p < 0.0021) were recorded after exposure with QPS. The arginine kinase 1 and calcium ATPase I showed highly significant (p < 0.0001) down-regulation in the drug kinetics. Therefore, the arginine kinase 1 and calcium ATPase I can be explored further to elucidate the trypanocidal activity of QPS. The preliminary data generated provide the potential of arginine kinase 1 and calcium ATPase I mRNA mediated pathway of trypanocidal action of QPS. Further, transcriptomics approach is required to investigate the possible mechanism of action of drugs at molecular level against the targeted organism.
Collapse
|
5
|
Tian LR, Lin MZ, Zhong HH, Cai YJ, Li B, Xiao ZC, Shuai XT. Nanodrug regulates lactic acid metabolism to reprogram the immunosuppressive tumor microenvironment for enhanced cancer immunotherapy. Biomater Sci 2022; 10:3892-3900. [PMID: 35686599 DOI: 10.1039/d2bm00650b] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A majority of cancers fail to respond to immunotherapy due to the immunosuppressive tumor microenvironment (TME), and metabolic regulation of the TME has been a promising strategy to improve immunotherapy. Lactate is a key metabolic player in tumor immune response since its excess secretion aggravates tumor immune escape by favoring the polarization of tumor-associated macrophages (TAMs) to an immunosuppressive phenotype meanwhile impeding the tumor infiltration of the cytotoxic T lymphocyte. Here, we proposed a metabolic reprogramming mechanism to ameliorate tumor immunosuppression by using lonidamine and syrosingopine incorporated liposomes (L@S/L) to regulate lactate production and efflux. Concretely, lonidamine reduced lactate production by affecting the glycolytic metabolic pathway while syrosingopine decreased lactate efflux by inhibiting the key protein expression of the lactate transporter MCT-4. Consequently, both the drugs synergistically normalize the pH of the TME to overcome the tumor immunosuppressive microenvironment. In vivo studies demonstrated that the decreased extracellular lactate preferentially polarized TAMs to the M1 phenotype, simultaneously increased the proportion of NK cells and reduced the number of Treg cells. These results validated an efficient tumor immunotherapy in the breast cancer model. This new strategy of lactic acid metabolism regulation is proposed to operate in concert with immune modulation in the TME, which shows great potential for immunotherapy of immunologically "cold" tumors.
Collapse
Affiliation(s)
- Li-Rong Tian
- PCFM Lab of Ministry of Education, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Min-Zhao Lin
- PCFM Lab of Ministry of Education, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Hui-Hai Zhong
- PCFM Lab of Ministry of Education, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Yu-Jun Cai
- PCFM Lab of Ministry of Education, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Bo Li
- Nanomedicine Research Center, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
| | - Ze-Cong Xiao
- Department of Minimally Invasive Interventional Radiology, and Laboratory of Interventional Radiology, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510275, China.
| | - Xin-Tao Shuai
- PCFM Lab of Ministry of Education, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.,Nanomedicine Research Center, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
| |
Collapse
|
6
|
Stryiński R, Mateos J, Carrera M, Jastrzębski JP, Bogacka I, Łopieńska-Biernat E. Tandem Mass Tagging (TMT) Reveals Tissue-Specific Proteome of L4 Larvae of Anisakis simplex s. s.: Enzymes of Energy and/or Carbohydrate Metabolism as Potential Drug Targets in Anisakiasis. Int J Mol Sci 2022; 23:ijms23084336. [PMID: 35457153 PMCID: PMC9027741 DOI: 10.3390/ijms23084336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 02/04/2023] Open
Abstract
Anisakis simplex s. s. is a parasitic nematode of marine mammals and causative agent of anisakiasis in humans. The cuticle and intestine of the larvae are the tissues most responsible for direct and indirect contact, respectively, of the parasite with the host. At the L4 larval stage, tissues, such as the cuticle and intestine, are fully developed and functional, in contrast to the L3 stage. As such, this work provides for the first time the tissue-specific proteome of A. simplex s. s. larvae in the L4 stage. Statistical analysis (FC ≥ 2; p-value ≤ 0.01) showed that 107 proteins were differentially regulated (DRPs) between the cuticle and the rest of the larval body. In the comparison between the intestine and the rest of the larval body at the L4 stage, 123 proteins were identified as DRPs. Comparison of the individual tissues examined revealed a total of 272 DRPs, with 133 proteins more abundant in the cuticle and 139 proteins more abundant in the intestine. Detailed functional analysis of the identified proteins was performed using bioinformatics tools. Glycolysis and the tricarboxylic acid cycle were the most enriched metabolic pathways by cuticular and intestinal proteins, respectively, in the L4 stage of A. simplex s. s. The presence of two proteins, folliculin (FLCN) and oxoglutarate dehydrogenase (OGDH), was confirmed by Western blot, and their tertiary structure was predicted and compared with other species. In addition, host–pathogen interactions were identified, and potential new allergens were predicted. The result of this manuscript shows the largest number of protein identifications to our knowledge using proteomics tools for different tissues of L4 larvae of A. simplex s. s. The identified tissue-specific proteins could serve as targets for new drugs against anisakiasis.
Collapse
Affiliation(s)
- Robert Stryiński
- Department of Biochemistry, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland
- Correspondence: (R.S.); (M.C.); (E.Ł.-B.)
| | - Jesús Mateos
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, 15-706 A Coruña, Spain;
| | - Mónica Carrera
- Department of Food Technology, Marine Research Institute (IIM), Spanish National Research Council (CSIC), 36-208 Vigo, Spain
- Correspondence: (R.S.); (M.C.); (E.Ł.-B.)
| | - Jan Paweł Jastrzębski
- Department of Plant Physiology, Genetics and Biotechnology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland;
| | - Iwona Bogacka
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland;
| | - Elżbieta Łopieńska-Biernat
- Department of Biochemistry, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland
- Correspondence: (R.S.); (M.C.); (E.Ł.-B.)
| |
Collapse
|
7
|
Guerrero-Hernández J, Bobes RJ, García-Varela M, Castellanos-Gonzalez A, Laclette JP. Identification and functional characterization of the siRNA pathway in Taenia crassiceps by silencing Enolase A. Acta Trop 2022; 225:106197. [PMID: 34688628 DOI: 10.1016/j.actatropica.2021.106197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 09/01/2021] [Accepted: 10/13/2021] [Indexed: 12/30/2022]
Abstract
A gene silencing procedure on cysticerci of the taeniid cestode Taenia crassiceps is described. This is the first time this technique is reported in this species that is widely used as an animal model for human cysticercosis. Genome database searches were performed in order to find out if relevant genes involved in gene silencing and non-coding RNA processing, Argonaute and Dicer (AGO and Dcr) are present in T. crassiceps. We found three AGO and two Dcr orthologues that were designed TcAGO1, Tc2 and Tc3, as well as TcDcr1 and TcDcr2. In order to elucidate the evolutionary relationships of T. crassiceps TcAGO and TcDcr genes, separate phylogenetic analyses were carried out for each, including AGO and Dcr orthologues of other 20 platyhelminthes. Our findings showed a close phylogenetic relationship of TcAGO and TcDcr with those previously described for Echinococcus spp. Our RT-PCR studies demonstrated expression of all TcAGO and TcDcr orthologues. Our results show that the gene silencing machinery in T. crassiceps is functionally active by inducing silencing of TcEnoA (∼90%). These results clearly show that gene silencing using siRNAs can be used as a molecular methodology to study gene function in taeniid cestodes.
Collapse
Affiliation(s)
- Julio Guerrero-Hernández
- Biomedical Research Institute. Universidad Nacional Autónoma de México, México, 04510, Coyoacán, Cd. de México, México
| | - Raúl J Bobes
- Biomedical Research Institute. Universidad Nacional Autónoma de México, México, 04510, Coyoacán, Cd. de México, México
| | - Martín García-Varela
- Biology Institute. Universidad Nacional Autónoma de México, 04510, Coyoacán, Cd. de México, México
| | - Alejandro Castellanos-Gonzalez
- Division of Infectious Diseases, University of Texas Medical Branch, United States; Center for Tropical Diseases, University of Texas Medical Branch, United States..
| | - Juan P Laclette
- Biomedical Research Institute. Universidad Nacional Autónoma de México, México, 04510, Coyoacán, Cd. de México, México.
| |
Collapse
|
8
|
Sampaio Guther ML, Prescott AR, Kuettel S, Tinti M, Ferguson MAJ. Nucleotide sugar biosynthesis occurs in the glycosomes of procyclic and bloodstream form Trypanosoma brucei. PLoS Negl Trop Dis 2021; 15:e0009132. [PMID: 33592041 PMCID: PMC7909634 DOI: 10.1371/journal.pntd.0009132] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 02/26/2021] [Accepted: 01/12/2021] [Indexed: 11/19/2022] Open
Abstract
In Trypanosoma brucei, there are fourteen enzymatic biotransformations that collectively convert glucose into five essential nucleotide sugars: UDP-Glc, UDP-Gal, UDP-GlcNAc, GDP-Man and GDP-Fuc. These biotransformations are catalyzed by thirteen discrete enzymes, five of which possess putative peroxisome targeting sequences. Published experimental analyses using immunofluorescence microscopy and/or digitonin latency and/or subcellular fractionation and/or organelle proteomics have localized eight and six of these enzymes to the glycosomes of bloodstream form and procyclic form T. brucei, respectively. Here we increase these glycosome localizations to eleven in both lifecycle stages while noting that one, phospho-N-acetylglucosamine mutase, also localizes to the cytoplasm. In the course of these studies, the heterogeneity of glycosome contents was also noted. These data suggest that, unlike other eukaryotes, all of nucleotide sugar biosynthesis in T. brucei is compartmentalized to the glycosomes in both lifecycle stages. The implications are discussed.
Collapse
Affiliation(s)
- Maria Lucia Sampaio Guther
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Alan R. Prescott
- Dundee Imaging Facility, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Sabine Kuettel
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michele Tinti
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael A. J. Ferguson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail:
| |
Collapse
|
9
|
Matta CBBD, Santos-Júnior PFDS, Gonçalves VT, Araújo MVD, Queiroz ACD, Silva JKS, Silva JFMD, Padilha RJR, Alves LC, Santos FABD, Barcellos LT, Silva-Júnior EFD, Araújo-Júnior JXD, Costa JBND, Sant’Anna CMR, Alexandre-Moreira MS. In vitro and in vivo evaluation of dialkylphosphorylhydrazones against Leishmania chagasi promastigotes and amastigotes. NEW J CHEM 2021. [DOI: 10.1039/d1nj03694g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In our study, two new dialkylphosphorylhydrazones have been designed targeting activity against L. braziliensis and L. amazonensis parasites, and their mechanism of action, as well as their leishmanicidal activity against L. chagasi, was evaluated.
Collapse
Affiliation(s)
- Carolina Barbosa Brito da Matta
- Laboratory of Pharmacology and Immunity, Institute of Biological Sciences and Health, Federal University of Alagoas, Campus A.C. Simões, Lourival Melo Mota Avenue, Maceió 57072-970, AL, Brazil
| | | | - Vinícius Tomaz Gonçalves
- Federal Center for Technology Education Celso Suckow da Fonseca (CEFET/RJ), Itaguaí 20271-110, RJ, Brazil
| | - Morgana Vital de Araújo
- Laboratory of Pharmacology and Immunity, Institute of Biological Sciences and Health, Federal University of Alagoas, Campus A.C. Simões, Lourival Melo Mota Avenue, Maceió 57072-970, AL, Brazil
| | - Aline Cavalcanti de Queiroz
- Laboratory of Pharmacology and Immunity, Institute of Biological Sciences and Health, Federal University of Alagoas, Campus A.C. Simões, Lourival Melo Mota Avenue, Maceió 57072-970, AL, Brazil
| | - João Kaycke Sarmento Silva
- Laboratory of Pharmacology and Immunity, Institute of Biological Sciences and Health, Federal University of Alagoas, Campus A.C. Simões, Lourival Melo Mota Avenue, Maceió 57072-970, AL, Brazil
| | - João Flávio Monteiro da Silva
- Laboratory of Pharmacology and Immunity, Institute of Biological Sciences and Health, Federal University of Alagoas, Campus A.C. Simões, Lourival Melo Mota Avenue, Maceió 57072-970, AL, Brazil
| | - Rafael José Ribeiro Padilha
- Laboratory of Immunopathology Keizo Asami (LIKA) and Biochemistry Department, Federal University of Pernambuco, Recife 50670-901, PE, Brazil
| | - Luiz Carlos Alves
- Laboratory of Immunopathology Keizo Asami (LIKA) and Aggeu Magalhães Research Center, CPqAM/FIOCRUZ, Federal University of Pernambuco, Av. Moraes Rego s/n, Cidade Universitária, Recife 50670-420, PE, Brazil
| | - Fábio André Brayner dos Santos
- Laboratory of Immunopathology Keizo Asami (LIKA) and Aggeu Magalhães Research Center, CPqAM/FIOCRUZ, Federal University of Pernambuco, Av. Moraes Rego s/n, Cidade Universitária, Recife 50670-420, PE, Brazil
| | - Lucas Tricarico Barcellos
- Rural Federal University of Rio de Janeiro, Institute of Chemistry, Seropédica 23970-000, RJ, Brazil
| | | | - João Xavier de Araújo-Júnior
- Rural Federal University of Rio de Janeiro, Institute of Chemistry, Seropédica 23970-000, RJ, Brazil
- Laboratory of Medicinal Chemistry, Pharmaceutical Sciences Institute, Federal University of Alagoas, Campus A.C. Simões, Lourival Melo Mota Avenue, Maceió 57072-970, Brazil
| | | | | | - Magna Suzana Alexandre-Moreira
- Laboratory of Pharmacology and Immunity, Institute of Biological Sciences and Health, Federal University of Alagoas, Campus A.C. Simões, Lourival Melo Mota Avenue, Maceió 57072-970, AL, Brazil
| |
Collapse
|
10
|
Repurposing bioenergetic modulators against protozoan parasites responsible for tropical diseases. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 14:17-27. [PMID: 32829099 PMCID: PMC7452664 DOI: 10.1016/j.ijpddr.2020.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/30/2022]
Abstract
Malaria, leishmaniasis and trypanosomiasis are arthropod-borne, parasitic diseases that constitute a major global health problem. They are generally found in developing countries, where lack of access to preventive tools and treatment hinders their management. Because these parasites share an increased demand on glucose consumption with most cancer cells, six compounds used in anti-tumoral research were selected to be tested as antiparasitic agents in in vitro models of Leishmania infantum, Trypanosoma brucei, T. cruzi, and Plasmodium falciparum: dichloroacetic acid (DCA), 3-bromopyruvic acid (3BP), 2-deoxy-D-glucose (2DG), lonidamine (LND), metformin (MET), and sirolimus (SIR). No parasite-killing activity was found in L. infantum promastigotes, whereas DCA and 3BP reduced the burden of intra-macrophagic amastigotes. For T. brucei all selected compounds, but 2DG, decreased parasite survival. DCA, 2DG, LND and MET showed parasite-killing activity in T. cruzi. Finally, anti-plasmodial activity was found for DCA, 2DG, LND, MET and SIR. These results reinforce the hypothesis that drugs with proven efficacy in the treatment of cancer by interfering with ATP production, proliferation, and survival cell strategies might be useful in treating threatening parasitic diseases and provide new opportunities for their repurposing. Parasitic diseases are prevalent among the poorest of the poor. Some parasitic protists degrade glucose into CO2 even aerobically making this a target. Degrading glucose into CO2 (Warburg effect) is also characteristic for cancer cells. Repurposing cancer glycolysis blockers may provide cost-effective treatments for the poorest.
Collapse
|
11
|
Xin Q, Yuan M, Li H, Song X, Lu J, Jing T. In vitro effects of lonidamine and 6-aminonicotinamide against Echinococcus granulosussensu stricto and Echinococcus multilocularis. Vet Res 2020; 51:29. [PMID: 32101153 PMCID: PMC7045558 DOI: 10.1186/s13567-020-00744-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/22/2020] [Indexed: 01/14/2023] Open
Abstract
Echinococcosis is a zoonotic disease caused by cestode species of the genus Echinococcus, which demonstrates considerable medical and veterinary concerns. The development of novel drugs for echinococcosis treatment is urgently needed. In this study, we demonstrated that lonidamine (LND) and 6-aminonicotinamide (6-AN) exhibited considerable in vitro effects against both larval- and adult-stage of E. granulosussensu stricto (s. s.) and E. multilocularis. The combination of LND and 6-AN exhibited a significantly higher activity than the single drug treatment. These results highlight the therapeutic potential of LND, 6-AN and the combination of LND and 6-AN for the treatment of echinococcosis.
Collapse
Affiliation(s)
- Qi Xin
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Miaomiao Yuan
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.,The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Huanping Li
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Xiaoxia Song
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Jun Lu
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Tao Jing
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
| |
Collapse
|
12
|
Garcia SN, Guedes RC, Marques MM. Unlocking the Potential of HK2 in Cancer Metabolism and Therapeutics. Curr Med Chem 2020; 26:7285-7322. [PMID: 30543165 DOI: 10.2174/0929867326666181213092652] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/26/2018] [Accepted: 11/06/2018] [Indexed: 12/24/2022]
Abstract
Glycolysis is a tightly regulated process in which several enzymes, such as Hexokinases (HKs), play crucial roles. Cancer cells are characterized by specific expression levels of several isoenzymes in different metabolic pathways and these features offer possibilities for therapeutic interventions. Overexpression of HKs (mostly of the HK2 isoform) have been consistently reported in numerous types of cancer. Moreover, deletion of HK2 has been shown to decrease cancer cell proliferation without explicit side effects in animal models, which suggests that targeting HK2 is a viable strategy for cancer therapy. HK2 inhibition causes a substantial decrease of glycolysis that affects multiple pathways of central metabolism and also destabilizes the mitochondrial outer membrane, ultimately enhancing cell death. Although glycolysis inhibition has met limited success, partly due to low selectivity for specific isoforms and excessive side effects of the reported HK inhibitors, there is ample ground for progress. The current review is focused on HK2 inhibition, envisaging the development of potent and selective anticancer agents. The information on function, expression, and activity of HKs is presented, along with their structures, known inhibitors, and reported effects of HK2 ablation/inhibition. The structural features of the different isozymes are discussed, aiming to stimulate a more rational approach to the design of selective HK2 inhibitors with appropriate drug-like properties. Particular attention is dedicated to a structural and sequence comparison of the structurally similar HK1 and HK2 isoforms, aiming to unveil differences that could be explored therapeutically. Finally, several additional catalytic- and non-catalytic roles on different pathways and diseases, recently attributed to HK2, are reviewed and their implications briefly discussed.
Collapse
Affiliation(s)
- Sara N Garcia
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.,iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Rita C Guedes
- iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - M Matilde Marques
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| |
Collapse
|
13
|
Goldman A, Khiste S, Freinkman E, Dhawan A, Majumder B, Mondal J, Pinkerton AB, Eton E, Medhi R, Chandrasekar V, Rahman MM, Ichimura T, Gopinath KS, Majumder P, Kohandel M, Sengupta S. Targeting tumor phenotypic plasticity and metabolic remodeling in adaptive cross-drug tolerance. Sci Signal 2019; 12:12/595/eaas8779. [PMID: 31431543 DOI: 10.1126/scisignal.aas8779] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Metastable phenotypic state transitions in cancer cells can lead to the development of transient adaptive resistance or tolerance to chemotherapy. Here, we report that the acquisition of a phenotype marked by increased abundance of CD44 (CD44Hi) by breast cancer cells as a tolerance response to routinely used cytotoxic drugs, such as taxanes, activated a metabolic switch that conferred tolerance against unrelated standard-of-care chemotherapeutic agents, such as anthracyclines. We characterized the sequence of molecular events that connected the induced CD44Hi phenotype to increased activity of both the glycolytic and oxidative pathways and glucose flux through the pentose phosphate pathway (PPP). When given in a specific order, a combination of taxanes, anthracyclines, and inhibitors of glucose-6-phosphate dehydrogenase (G6PD), an enzyme involved in glucose metabolism, improved survival in mouse models of breast cancer. The same sequence of the three-drug combination reduced the viability of patient breast tumor samples in an explant system. Our findings highlight a convergence between phenotypic and metabolic state transitions that confers a survival advantage to cancer cells against clinically used drug combinations. Pharmacologically targeting this convergence could overcome cross-drug tolerance and could emerge as a new paradigm in the treatment of cancer.
Collapse
Affiliation(s)
- Aaron Goldman
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA. .,Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.,Mitra Biotech, Integrative Immuno-Oncology Center, Woburn, MA 01801, USA
| | - Sachin Khiste
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.,Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Elizaveta Freinkman
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Andrew Dhawan
- School of Medicine, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Biswanath Majumder
- Mitra Biotech, Integrative Immuno-Oncology Center, Woburn, MA 01801, USA.,Mitra Biotech, 7, Service Road, Pragathi Nagar, Electronic City, Bengaluru, Karnataka 560100, India
| | - Jayanta Mondal
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.,Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | | | - Elliot Eton
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Ragini Medhi
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Vineethkrishna Chandrasekar
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - M Mamunur Rahman
- Medical and Biological Laboratories International, Woburn, MA 01801, USA
| | - Takaharu Ichimura
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Kodaganur S Gopinath
- Department of Surgical Oncology, HCG Bangalore Institute of Oncology Specialty Center, Bengaluru, Karnataka 560027, India
| | - Pradip Majumder
- Mitra Biotech, Integrative Immuno-Oncology Center, Woburn, MA 01801, USA
| | - Mohammad Kohandel
- Department of Applied Mathematics, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Shiladitya Sengupta
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA. .,Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.,Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.,Dana Farber Cancer Institute, Boston, MA 02115, USA
| |
Collapse
|
14
|
Mercaldi GF, D'Antonio EL, Aguessi A, Rodriguez A, Cordeiro AT. Discovery of antichagasic inhibitors by high-throughput screening with Trypanosoma cruzi glucokinase. Bioorg Med Chem Lett 2019; 29:1948-1953. [PMID: 31133533 DOI: 10.1016/j.bmcl.2019.05.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/17/2019] [Accepted: 05/18/2019] [Indexed: 12/14/2022]
Abstract
A high-throughput screening (HTS) campaign was carried out for Trypanosoma cruzi glucokinase (TcGlcK), a potential drug-target of the pathogenic protozoan parasite. Glycolysis and the pentose phosphate pathway (PPP) are important metabolic pathways for T. cruzi and the inhibition of the glucose kinases (i.e. glucokinase and hexokinase) may be a strategic approach for drug discovery. Glucose kinases phosphorylate d-glucose with co-substrate ATP to yield G6P, and moreover, the produced G6P enters both pathways for catabolism. The TcGlcK - HTS campaign revealed 25 novel enzyme inhibitors that were distributed in nine chemical classes and were discovered from a primary screen of 13,040 compounds. Thirteen of these compounds were found to have low micromolar IC50 enzyme - inhibition values; strikingly, four of those compounds exhibited low toxicity towards NIH-3T3 murine host cells and notable in vitro trypanocidal activity. These compounds were of three chemical classes: (a) the 3-nitro-2-phenyl-2H-chromene scaffold, (b) the N-phenyl-benzenesulfonamide scaffold, and (c) the gossypol scaffold. Two compounds from the 3-nitro-2-phenyl-2H-chromene scaffold were determined to be hit-to-lead candidates that can proceed further down the early-stage drug discovery process.
Collapse
Affiliation(s)
- Gustavo F Mercaldi
- Brazilian Center for Research in Energy and Materials, Brazilian Biosciences National Laboratory, Campinas, SP 13083-970, Brazil
| | - Edward L D'Antonio
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, SC 29909, USA.
| | - Annelie Aguessi
- Department of Microbiology, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA
| | - Ana Rodriguez
- Department of Microbiology, New York University School of Medicine, 430 East 29th Street, New York, NY 10016, USA
| | - Artur T Cordeiro
- Brazilian Center for Research in Energy and Materials, Brazilian Biosciences National Laboratory, Campinas, SP 13083-970, Brazil
| |
Collapse
|
15
|
Osorio-Méndez JF, Cevallos AM. Discovery and Genetic Validation of Chemotherapeutic Targets for Chagas' Disease. Front Cell Infect Microbiol 2019; 8:439. [PMID: 30666299 PMCID: PMC6330712 DOI: 10.3389/fcimb.2018.00439] [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: 07/01/2018] [Accepted: 12/10/2018] [Indexed: 01/06/2023] Open
Abstract
There is an urgent need to develop new treatments for Chagas' disease. To identify drug targets, it is important to understand the basic biology of Trypanosoma cruzi, in particular with respect to the biological pathways or proteins that are essential for its survival within the host. This review provides a streamlined approach for identifying drug targets using freely available chemogenetic databases and outlines the relevant characteristics of an ideal chemotherapeutic target. Among those are their essentiality, druggability, availability of structural information, and selectivity. At the moment only 16 genes have been found as essential by gene disruption in T. cruzi. At the TDR Targets database, a chemogenomics resource for neglected diseases, information about published structures for these genes was only found for three of these genes, and annotation of validated inhibitors was found in two. These inhibitors have activity against the parasitic stages present in the host. We then analyzed three of the pathways that are considered promising in the search for new targets: (1) Ergosterol biosynthesis, (2) Resistance to oxidative stress, (3) Synthesis of surface glycoconjugates. We have annotated all the genes that participate in them, identified those that are considered as druggable, and incorporated evidence from either Trypanosoma brucei, and Leishmania spp. that supports the hypothesis that these pathways are essential for T. cruzi survival.
Collapse
Affiliation(s)
- Juan Felipe Osorio-Méndez
- Laboratorio de Microbiología y Biología Molecular, Programa de Medicina, Corporación Universitaria Empresarial Alexander von Humboldt, Armenia, Colombia.,Grupo de Estudio en Parasitología Molecular, Centro de Investigaciones Biomédicas, Universidad del Quindío, Armenia, Colombia
| | - Ana María Cevallos
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| |
Collapse
|
16
|
Callaghan NI, Williams KJ, MacCormack TJ. Cardioprotective mitochondrial binding by hexokinase I is induced by a hyperoxic acute thermal insult in the rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol B Biochem Mol Biol 2018; 224:45-52. [DOI: 10.1016/j.cbpb.2017.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/07/2017] [Accepted: 07/13/2017] [Indexed: 12/20/2022]
|
17
|
Moreno SA, Cantos GV. The kinetic properties of hexokinases in African trypanosomes of the subgenus Trypanozoon match the blood glucose levels of mammal hosts. Comp Biochem Physiol B Biochem Mol Biol 2017; 217:51-59. [PMID: 29277605 DOI: 10.1016/j.cbpb.2017.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 12/08/2017] [Accepted: 12/15/2017] [Indexed: 11/29/2022]
Abstract
We hypothesize that the hexokinases of trypanosomes of the subgenus Trypanozoon match the blood glucose levels of hosts. We studied the kinetic properties of purified hexokinase in T. equiperdum (specific activity=302U/mg), and compare with other members of Trypanozoon. With ATP (Km=104.7μM) as phosphate donor, hexokinase catalyzes the phosphorylation of glucose (Km=24.9μM) and mannose (Km=8.8μM). With respect to glucose, mannose and inorganic pyrophosphate respectively are a competitive, and a mixed inhibitor of hexokinase. With respect to ATP, both are mixed inhibitors of this enzyme. In T. equiperdum, hexokinase shows a high affinity for glucose. Pleomorphism-transformation of trypanosomes from a multiplicative to a non-multiplicative form-results in a self-limited growth stabilizing glucose consumption. It delays the death of the host, thus prolonging its exposure to tsetse flies. When glucose levels descend, top-down regulation allows trypanosomes to survive through the expression of alternative metabolic pathways. It accelerates the death of the host, but helps trypanosome density to increase enough to ensure transmission without tsetse flies. Pleomorphism, and a hexokinase with a high affinity for glucose, are two main adaptive traits of T. b. brucei. The latter trait, and a strong top-down regulation, are two main adaptive traits of T. equiperdum. For trypanosomes living in glucose-rich blood, a hexokinase with a high affinity for glucose would unnecessarily harm hosts. This may explain why the human parasites, T. b. gambiense and T. b. rhodesiense, possess hexokinases with a low affinity for glucose.
Collapse
Affiliation(s)
- S Andrea Moreno
- Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 05101, Venezuela.
| | | |
Collapse
|
18
|
Flaherty DP, Harris MT, Schroeder CE, Khan H, Kahney EW, Hackler AL, Patrick SL, Weiner WS, Aubé J, Sharlow ER, Morris JC, Golden JE. Optimization and Evaluation of Antiparasitic Benzamidobenzoic Acids as Inhibitors of Kinetoplastid Hexokinase 1. ChemMedChem 2017; 12:1994-2005. [PMID: 29105342 PMCID: PMC5808564 DOI: 10.1002/cmdc.201700592] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 10/26/2017] [Indexed: 11/05/2022]
Abstract
Kinetoplastid-based infections are neglected diseases that represent a significant human health issue. Chemotherapeutic options are limited due to toxicity, parasite susceptibility, and poor patient compliance. In response, we studied a molecular-target-directed approach involving intervention of hexokinase activity-a pivotal enzyme in parasite metabolism. A benzamidobenzoic acid hit with modest biochemical inhibition of Trypanosoma brucei hexokinase 1 (TbHK1, IC50 =9.1 μm), low mammalian cytotoxicity (IMR90 cells, EC50 >25 μm), and no appreciable activity on whole bloodstream-form (BSF) parasites was optimized to afford a probe with improved TbHK1 potency and, significantly, efficacy against whole BSF parasites (TbHK1, IC50 =0.28 μm; BSF, ED50 =1.9 μm). Compounds in this series also inhibited the hexokinase enzyme from Leishmania major (LmHK1), albeit with less potency than toward TbHK1, suggesting that inhibition of the glycolytic pathway may be a promising opportunity to target multiple disease-causing trypanosomatid protozoa.
Collapse
Affiliation(s)
- Daniel P Flaherty
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
- Present Address: Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN, 47907, USA
| | - Michael T Harris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
- Present Address: Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Chad E Schroeder
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
| | - Haaris Khan
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Elizabeth W Kahney
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
- Present Address: Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Amber L Hackler
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Stephen L Patrick
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Warren S Weiner
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
| | - Jeffrey Aubé
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
- Present Address: School of Pharmacy, University of North Carolina, 3012 Marsico Hall, 125 Mason Farm Road, Chapel Hill, NC, 27599, USA
| | - Elizabeth R Sharlow
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Jennifer E Golden
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
- Present Address: School of Pharmacy, Department of Pharmaceutical Sciences, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI, 53705, USA
| |
Collapse
|
19
|
Gordhan HM, Milanes JE, Qiu Y, Golden JE, Christensen KA, Morris JC, Whitehead DC. A targeted delivery strategy for the development of potent trypanocides. Chem Commun (Camb) 2017; 53:8735-8738. [PMID: 28726862 PMCID: PMC5576345 DOI: 10.1039/c7cc03378h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new drug delivery strategy was investigated for the development of potent anti-parasitic compounds against Trypanosoma brucei, the causative agent of African sleeping sickness. Thus, potent in vitro hexokinase inhibitors were rendered cytotoxic by appending a tripeptide peroxosomal targeting sequence that facilitated delivery of the molecular cargo to the appropriate organelle in the parasite.
Collapse
Affiliation(s)
| | - Jillian E Milanes
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.
| | - Yijian Qiu
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.
| | - Jennifer E Golden
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin, Madison, WI, USA
| | | | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.
| | | |
Collapse
|
20
|
Gordhan HM, Patrick SL, Swasy MI, Hackler AL, Anayee M, Golden JE, Morris JC, Whitehead DC. Evaluation of substituted ebselen derivatives as potential trypanocidal agents. Bioorg Med Chem Lett 2016; 27:537-541. [PMID: 28043795 DOI: 10.1016/j.bmcl.2016.12.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 10/20/2022]
Abstract
Human African trypanosomiasis is a disease of sub-Saharan Africa, where millions are at risk for the illness. The disease, commonly referred to as African sleeping sickness, is caused by an infection by the eukaryotic pathogen, Trypanosoma brucei. Previously, a target-based high throughput screen revealed ebselen (EbSe), and its sulfur analog, EbS, to be potent in vitro inhibitors of the T. brucei hexokinase 1 (TbHK1). These molecules also exhibited potent trypanocidal activity in vivo. In this manuscript, we synthesized a series of sixteen EbSe and EbS derivatives bearing electron-withdrawing carboxylic acid and methyl ester functional groups, and evaluated the influence of these substituents on the biological efficacy of the parent scaffold. With the exception of one methyl ester derivative, these modifications ablated or blunted the potent TbHK1 inhibition of the parent scaffold. Nonetheless, a few of the methyl ester derivatives still exhibited trypanocidal effects with single-digit micromolar or high nanomolar EC50 values.
Collapse
Affiliation(s)
- Heeren M Gordhan
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA
| | - Stephen L Patrick
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, 249 Life Sciences Building, Clemson University, Clemson, SC 29634, USA
| | - Maria I Swasy
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA
| | - Amber L Hackler
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, 249 Life Sciences Building, Clemson University, Clemson, SC 29634, USA
| | - Mark Anayee
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA
| | - Jennifer E Golden
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin, 777 Highland Ave., Madison, WI 53705-2222, USA
| | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, 249 Life Sciences Building, Clemson University, Clemson, SC 29634, USA.
| | - Daniel C Whitehead
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA.
| |
Collapse
|
21
|
Abstract
Hexokinase 2 (HK2) has been identified as an oncogene in some malignant diseases such as breast cancer and ovarian cancer. However, the role of HK2 in lung cancer remains unclear. In this study, we explored the functional role of HK2 in lung cancer cell proliferation and tumorigenesis and determine its expression profile in lung cancer. HK2 expression was increased in primary lung cancer tissues of patients. Knocking down HK2 expression by small interfering RNA (siRNA) inhibited cell proliferation in lung cancer cells and nude mice. Thus, HK2 is required for sustained proliferation and survival of tumor cells in vitro and in vivo, and its aberrant expression may contribute to the pathogenesis of lung cancer. Thus, our study provided evidence that HK2 functions as a novel oncogene in lung cancer and may be a potential therapeutic target for lung cancer.
Collapse
Affiliation(s)
- Feng Xi
- Respiratory Department of Medicine, Shanghai Pudong New Area People's Hospital, Shanghai, China
| | | |
Collapse
|
22
|
Identification of Novel Plasmodium falciparum Hexokinase Inhibitors with Antiparasitic Activity. Antimicrob Agents Chemother 2016; 60:6023-33. [PMID: 27458230 DOI: 10.1128/aac.00914-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/19/2016] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum, the deadliest species of malaria parasites, is dependent on glycolysis for the generation of ATP during the pathogenic red blood cell stage. Hexokinase (HK) catalyzes the first step in glycolysis, transferring the γ-phosphoryl group of ATP to glucose to yield glucose-6-phosphate. Here, we describe the validation of a high-throughput assay for screening small-molecule collections to identify inhibitors of the P. falciparum HK (PfHK). The assay, which employed an ADP-Glo reporter system in a 1,536-well-plate format, was robust with a signal-to-background ratio of 3.4 ± 1.2, a coefficient of variation of 6.8% ± 2.9%, and a Z'-factor of 0.75 ± 0.08. Using this assay, we screened 57,654 molecules from multiple small-molecule collections. Confirmed hits were resolved into four clusters on the basis of structural relatedness. Multiple singleton hits were also identified. The most potent inhibitors had 50% inhibitory concentrations as low as ∼1 μM, and several were found to have low-micromolar 50% effective concentrations against asexual intraerythrocytic-stage P. falciparum parasites. These molecules additionally demonstrated limited toxicity against a panel of mammalian cells. The identification of PfHK inhibitors with antiparasitic activity using this validated screening assay is encouraging, as it justifies additional HTS campaigns with more structurally amenable libraries for the identification of potential leads for future therapeutic development.
Collapse
|
23
|
D'Antonio EL, Deinema MS, Kearns SP, Frey TA, Tanghe S, Perry K, Roy TA, Gracz HS, Rodriguez A, D'Antonio J. Structure-based approach to the identification of a novel group of selective glucosamine analogue inhibitors of Trypanosoma cruzi glucokinase. Mol Biochem Parasitol 2016; 204:64-76. [PMID: 26778112 DOI: 10.1016/j.molbiopara.2015.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 12/10/2015] [Accepted: 12/16/2015] [Indexed: 01/29/2023]
Abstract
Glucokinase and hexokinase from pathogenic protozoa Trypanosoma cruzi are potential drug targets for antiparasitic chemotherapy of Chagas' disease. These glucose kinases phosphorylate d-glucose with co-substrate ATP and yield glucose 6-phosphate and are involved in essential metabolic pathways, such as glycolysis and the pentose phosphate pathway. An inhibitor class was conceived that is selective for T. cruzi glucokinase (TcGlcK) using structure-based drug design involving glucosamine having a linker from the C2 amino that terminates with a hydrophobic group either being phenyl, p-hydroxyphenyl, or dioxobenzo[b]thiophenyl groups. The synthesis and characterization for two of the four compounds are presented while the other two compounds were commercially available. Four high-resolution X-ray crystal structures of TcGlcK inhibitor complexes are reported along with enzyme inhibition constants (Ki) for TcGlcK and Homo sapiens hexokinase IV (HsHxKIV). These glucosamine analogue inhibitors include three strongly selective TcGlcK inhibitors and a fourth inhibitor, benzoyl glucosamine (BENZ-GlcN), which is a similar variant exhibiting a shorter linker. Carboxybenzyl glucosamine (CBZ-GlcN) was found to be the strongest glucokinase inhibitor known to date, having a Ki of 0.71±0.05μM. Also reported are two biologically active inhibitors against in vitro T. cruzi culture that were BENZ-GlcN and CBZ-GlcN, with intracellular amastigote growth inhibition IC50 values of 16.08±0.16μM and 48.73±0.69μM, respectively. These compounds revealed little to no toxicity against mammalian NIH-3T3 fibroblasts and provide a key starting point for further drug development with this class of compound.
Collapse
Affiliation(s)
- Edward L D'Antonio
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA.
| | - Mason S Deinema
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Sean P Kearns
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Tyler A Frey
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Scott Tanghe
- Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | - Kay Perry
- NE-CAT, Department of Chemistry and Chemical Biology, Cornell University, Building 436E, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - Timothy A Roy
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Hanna S Gracz
- Department of Molecular and Structural Biochemistry, North Carolina State University, 128 Polk Hall, Raleigh, North Carolina 27695, USA
| | - Ana Rodriguez
- Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | - Jennifer D'Antonio
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| |
Collapse
|
24
|
Akhenblit PJ, Pagel MD. Recent Advances in Targeting Tumor Energy Metabolism with Tumor Acidosis as a Biomarker of Drug Efficacy. ACTA ACUST UNITED AC 2016; 8:20-29. [PMID: 26962408 PMCID: PMC4780427 DOI: 10.4172/1948-5956.1000382] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cancer cells employ a deregulated cellular metabolism to leverage survival and growth advantages. The unique tumor energy metabolism presents itself as a promising target for chemotherapy. A pool of tumor energy metabolism targeting agents has been developed after several decades of efforts. This review will cover glucose and fatty acid metabolism, PI3K/AKT/mTOR, HIF-1 and glutamine pathways in tumor energy metabolism, and how they are being exploited for treatments and therapies by promising pre-clinical or clinical drugs being developed or investigated. Additionally, acidification of the tumor extracellular microenvironment is hypothesized to be the result of active tumor metabolism. This implies that tumor extracellular pH (pHe) can be a biomarker for assessing the efficacy of therapies that target tumor metabolism. Several translational molecular imaging methods (PET, MRI) for interrogating tumor acidification and its suppression are discussed as well.
Collapse
Affiliation(s)
- Paul J Akhenblit
- Cancer Biology Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA
| | - Mark D Pagel
- Cancer Biology Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA; Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
| |
Collapse
|
25
|
Hauge M, Bruserud Ø, Hatfield KJ. Targeting of cell metabolism in human acute myeloid leukemia - more than targeting of isocitrate dehydrogenase mutations and PI3K/AKT/mTOR signaling? Eur J Haematol 2015; 96:211-21. [DOI: 10.1111/ejh.12690] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Michelle Hauge
- Department of Medicine; Haukeland University Hospital; Bergen Norway
| | - Øystein Bruserud
- Department of Medicine; Haukeland University Hospital; Bergen Norway
- Department of Clinical Science; University of Bergen; Bergen Norway
| | | |
Collapse
|
26
|
In silico search of energy metabolism inhibitors for alternative leishmaniasis treatments. BIOMED RESEARCH INTERNATIONAL 2015; 2015:965725. [PMID: 25918726 PMCID: PMC4396002 DOI: 10.1155/2015/965725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/08/2014] [Accepted: 09/14/2014] [Indexed: 12/12/2022]
Abstract
Leishmaniasis is a complex disease that affects mammals and is caused by approximately 20 distinct protozoa from the genus Leishmania. Leishmaniasis is an endemic disease that exerts a large socioeconomic impact on poor and developing countries. The current treatment for leishmaniasis is complex, expensive, and poorly efficacious. Thus, there is an urgent need to develop more selective, less expensive new drugs. The energy metabolism pathways of Leishmania include several interesting targets for specific inhibitors. In the present study, we sought to establish which energy metabolism enzymes in Leishmania could be targets for inhibitors that have already been approved for the treatment of other diseases. We were able to identify 94 genes and 93 Leishmania energy metabolism targets. Using each gene's designation as a search criterion in the TriTrypDB database, we located the predicted peptide sequences, which in turn were used to interrogate the DrugBank, Therapeutic Target Database (TTD), and PubChem databases. We identified 44 putative targets of which 11 are predicted to be amenable to inhibition by drugs which have already been approved for use in humans for 11 of these targets. We propose that these drugs should be experimentally tested and potentially used in the treatment of leishmaniasis.
Collapse
|
27
|
Loureiro I, Faria J, Clayton C, Macedo-Ribeiro S, Santarém N, Roy N, Cordeiro-da-Siva A, Tavares J. Ribose 5-phosphate isomerase B knockdown compromises Trypanosoma brucei bloodstream form infectivity. PLoS Negl Trop Dis 2015; 9:e3430. [PMID: 25568941 PMCID: PMC4287489 DOI: 10.1371/journal.pntd.0003430] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/21/2014] [Indexed: 12/13/2022] Open
Abstract
Ribose 5-phosphate isomerase is an enzyme involved in the non-oxidative branch of the pentose phosphate pathway, and catalyzes the inter-conversion of D-ribose 5-phosphate and D-ribulose 5-phosphate. Trypanosomatids, including the agent of African sleeping sickness namely Trypanosoma brucei, have a type B ribose-5-phosphate isomerase. This enzyme is absent from humans, which have a structurally unrelated ribose 5-phosphate isomerase type A, and therefore has been proposed as an attractive drug target waiting further characterization. In this study, Trypanosoma brucei ribose 5-phosphate isomerase B showed in vitro isomerase activity. RNAi against this enzyme reduced parasites' in vitro growth, and more importantly, bloodstream forms infectivity. Mice infected with induced RNAi clones exhibited lower parasitaemia and a prolonged survival compared to control mice. Phenotypic reversion was achieved by complementing induced RNAi clones with an ectopic copy of Trypanosoma cruzi gene. Our results present the first functional characterization of Trypanosoma brucei ribose 5-phosphate isomerase B, and show the relevance of an enzyme belonging to the non-oxidative branch of the pentose phosphate pathway in the context of Trypanosoma brucei infection. Within the non-oxidative branch of the pentose phosphate pathway, ribose 5-phosphate isomerase catalyzes the inter-conversion of ribose 5-phosphate and ribulose 5-phosphate. There are two types of ribose 5-phosphate isomerase, namely A and B. The presence of type B in Trypanosoma brucei, and its absence in humans, make this protein a promising drug target. African sleeping sickness is a serious parasitic disease that relies on limited chemotherapeutic options for control. In our study, a functional characterization of Trypanosoma brucei ribose 5-phosphate isomerase B is reported. Biochemical studies confirmed enzyme isomerase activity and its downregulation by RNAi affected mainly parasites infectivity in vivo. Overall this study shows that ribose 5-phosphate isomerase depletion is detrimental for parasites infectivity under host pressure.
Collapse
Affiliation(s)
- Inês Loureiro
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Joana Faria
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH cv Alliance, Heidelberg, Germany
| | - Sandra Macedo-Ribeiro
- Protein Crystallography Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Nuno Santarém
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
| | - Nilanjan Roy
- Ashok & Rita Patel Institute of Integrated Study & Research in Biotechnology & Allied Sciences, New Vallabh Vidyanagar, Dist-Anand, Gujarat, India
| | - Anabela Cordeiro-da-Siva
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Departamento de Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
- * E-mail: (ACdS); (JT)
| | - Joana Tavares
- Parasite Disease Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- * E-mail: (ACdS); (JT)
| |
Collapse
|
28
|
Merritt C, Silva L, Tanner AL, Stuart K, Pollastri MP. Kinases as druggable targets in trypanosomatid protozoan parasites. Chem Rev 2014; 114:11280-304. [PMID: 26443079 PMCID: PMC4254031 DOI: 10.1021/cr500197d] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Indexed: 12/21/2022]
Affiliation(s)
- Christopher Merritt
- Seattle
Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, Washington 98109-5219, United States
| | - Lisseth
E. Silva
- Department
of Chemistry & Chemical Biology, Northeastern
University, 417 Egan
Research Center, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Angela L. Tanner
- Department
of Chemistry & Chemical Biology, Northeastern
University, 417 Egan
Research Center, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Kenneth Stuart
- Seattle
Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, Washington 98109-5219, United States
| | - Michael P. Pollastri
- Department
of Chemistry & Chemical Biology, Northeastern
University, 417 Egan
Research Center, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| |
Collapse
|
29
|
A unique hexokinase in Cryptosporidium parvum, an apicomplexan pathogen lacking the Krebs cycle and oxidative phosphorylation. Protist 2014; 165:701-14. [PMID: 25216472 DOI: 10.1016/j.protis.2014.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 08/10/2014] [Accepted: 08/13/2014] [Indexed: 01/25/2023]
Abstract
Cryptosporidium parvum may cause virtually untreatable infections in AIDS patients, and is recently identified as one of the top four diarrheal pathogens in children in developing countries. Cryptosporidium differs from other apicomplexans (e.g., Plasmodium and Toxoplasma) by lacking many metabolic pathways including the Krebs cycle and cytochrome-based respiratory chain, thus relying mainly on glycolysis for ATP production. Here we report the molecular and biochemical characterizations of a hexokinase in C. parvum (CpHK). Our phylogenetic reconstructions indicated that apicomplexan hexokinases including CpHK were highly divergent from those of humans and animals (i.e., at the base of the eukaryotic clade). CpHK displays unique kinetic features that differ from those in mammals and Toxoplasma gondii (TgHK) in the preference towards various hexoses and its capacity to use ATP and other NTPs. CpHK also displays substrate inhibition by ATP. Moreover, 2-deoxy-D-glucose (2DG) could not only inhibit the CpHK activity, but also the parasite growth in vitro at concentrations nontoxic to host cells (IC(50) = 0.54 mM). While the exact action of 2-deoxy-D-glucose on the parasite is subject to further verification, our data suggest that CpHK and the glycolytic pathway may be explored for developing anti-cryptosporidial therapeutics.
Collapse
|
30
|
Smirlis D, Soares MBP. Selection of molecular targets for drug development against trypanosomatids. Subcell Biochem 2014; 74:43-76. [PMID: 24264240 DOI: 10.1007/978-94-007-7305-9_2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Trypanosomatid parasites are a group of flagellated protozoa that includes the genera Leishmania and Trypanosoma, which are the causative agents of diseases (leishmaniases, sleeping sickness and Chagas disease) that cause considerable morbidity and mortality, affecting more than 27 million people worldwide. Today no effective vaccines for the prevention of these diseases exist, whereas current chemotherapy is ineffective, mainly due to toxic side effects of current drugs and to the emergence of drug resistance and lack of cost effectiveness. For these reasons, rational drug design and the search of good candidate drug targets is of prime importance. The search for drug targets requires a multidisciplinary approach. To this end, the completion of the genome project of many trypanosomatid species gives a vast amount of new information that can be exploited for the identification of good drug candidates with a prediction of "druggability" and divergence from mammalian host proteins. In addition, an important aspect in the search for good drug targets is the "target identification" and evaluation in a biological pathway, as well as the essentiality of the gene in the mammalian stage of the parasite, which is provided by basic research and genetic and proteomic approaches. In this chapter we will discuss how these bioinformatic tools and experimental evaluations can be integrated for the selection of candidate drug targets, and give examples of metabolic and signaling pathways in the parasitic protozoa that can be exploited for rational drug design.
Collapse
|
31
|
Evaluation of the In Vitro Efficacy of Artemisia annua, Rumex abyssinicus, and Catha edulis Forsk Extracts in Cancer and Trypanosoma brucei Cells. ISRN BIOCHEMISTRY 2013; 2013:910308. [PMID: 25937964 PMCID: PMC4392988 DOI: 10.1155/2013/910308] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 08/13/2013] [Indexed: 11/17/2022]
Abstract
The current drugs against sleeping sickness are derived from cancer chemotherapeutic approaches. Herein, we aimed at evaluating the in vitro effect of alcoholic extracts of Artemisia annua (AMR), Rumex abyssinicus (RMA), and Catha edulis Forsk (CEF) on proliferation/viability of 1321N1 astrocytoma, MCF-7 breast cancer, THP-1 leukemia, and LNCaP, Du-145, and PC-3 prostate cancer cells and on Trypanosoma brucei cells. Proliferation of tumor cells was evaluated by WST-1 assay and viability/behaviour of T. brucei by cell counting and light microscopy. CEF was the most efficient growth inhibitor in comparison to AMR and RMA. Nevertheless, in LNCaP and THP-1 cells, all extracts significantly inhibited tumor growth at 3 μg/mL. All extracts inhibited proliferation of T. brucei cells in a concentration-dependent manner. Microscopic analysis revealed that 95% of the T. brucei cells died when exposed to 33 μg/mL CEF for 3 hrs. Similar results were obtained using 33 μg/mL AMR for 6 hrs. In case of RMA, however, higher concentrations were necessary to obtain similar effects on T. brucei. This demonstrates the antitumor efficacy of these extracts as well as their ability to dampen viability and proliferation of T. brucei, suggesting a common mechanism of action on highly proliferative cells, most probably by targeting cell metabolism.
Collapse
|
32
|
Joice AC, Harris MT, Kahney EW, Dodson HC, Maselli AG, Whitehead DC, Morris JC. Exploring the mode of action of ebselen in Trypanosoma brucei hexokinase inhibition. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2013; 3:154-60. [PMID: 24533305 PMCID: PMC3862409 DOI: 10.1016/j.ijpddr.2013.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Trypanosoma brucei hexokinase 1 is irreversibly inhibited by ebselen. Mutation of Cys residues did not change hexamer abundance. Active variants bearing Cys mutations were inhibited by ebselen. ESI–MS/MS indicated that the essential Cys327 was oxidized by ebselen.
Glycolysis is essential to Trypanosoma brucei, the causative agent of African sleeping sickness, suggesting enzymes in the pathway could be targets for drug development. Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one, EbSe) was identified in a screen as a potent inhibitor of T. brucei hexokinase 1 (TbHK1), the first enzyme in the pathway. EbSe has a history of promiscuity as an enzyme inhibitor, inactivating proteins through seleno-sulfide conjugation with Cys residues. Indeed, dilution of TbHK1 and inhibitor following incubation did not temper inhibition suggesting conjugate formation. Using mass spectrometry to analyze EbSe-based modifications revealed that two Cys residues (C327 and C369) were oxidized after treatment. Site-directed mutagenesis of C327 led to enzyme inactivation indicating that C327 was essential for catalysis. C369 was not essential, suggesting that EbSe inhibition of TbHK1 was the consequence of modification of C327 via thiol oxidation. Additionally, neither EbSe treatment nor mutation of the nine TbHK1 Cys residues appreciably altered enzyme quaternary structure.
Collapse
Key Words
- BSF, bloodstream form
- EbS, 2-phenyl-12-benzisothiazol-3(2H)-one
- EbSe, ebselen (2-phenyl-12-benzisoselenazol-3(2H)-one)
- Ebselen
- G6-P, glucose-6-phosphate
- G6PDH, glucose-6-phosphate dehydrogenase
- GK, glycerol kinase
- Gly3P, glycerol-3-phosphate
- HK, hexokinase
- Hexokinase
- Inhibitors
- PF, procyclic form
- TbHK, T. brucei hexokinase
- Trypanosoma brucei
- rTbHK1, recombinant Trypanosoma brucei hexokinase 1
Collapse
Affiliation(s)
- April C Joice
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Michael T Harris
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Elizabeth W Kahney
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Heidi C Dodson
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Andrew G Maselli
- Department of Biological Sciences, Chicago State University, Chicago, IL 60628, United States
| | - Daniel C Whitehead
- Department of Chemistry, Clemson University, Clemson, SC 29634, United States
| | - James C Morris
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| |
Collapse
|
33
|
Joice AC, Lyda TL, Sayce AC, Verplaetse E, Morris MT, Michels PAM, Robinson DR, Morris JC. Extra-glycosomal localisation of Trypanosoma brucei hexokinase 2. Int J Parasitol 2012; 42:401-9. [PMID: 22619756 DOI: 10.1016/j.ijpara.2012.02.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The majority of the glycolytic enzymes in the African trypanosome are compartmentalised within peroxisome-like organelles, the glycosomes. Polypeptides harbouring peroxisomal targeting sequences (PTS type 1 or 2) are targeted to these organelles. This targeting is essential to parasite viability, as compartmentalisation of glycolytic enzymes prevents unregulated ATP-dependent phosphorylation of intermediate metabolites. Here, we report the surprising extra-glycosomal localisation of a PTS-2 bearing trypanosomal hexokinase, TbHK2. In bloodstream form parasites, the protein localises to both glycosomes and to the flagellum. Evidence for this includes fractionation and immunofluorescence studies using antisera generated against the authentic protein as well as detection of epitope-tagged recombinant versions of the protein. In the insect stage parasite, distribution is different, with the polypeptide localised to glycosomes and proximal to the basal bodies. The function of the extra-glycosomal protein remains unclear. While its association with the basal body suggests that it may have a role in locomotion in the insect stage parasite, no detectable defect in directional motility or velocity of cell movement were observed for TbHK2-deficient cells, suggesting that the protein may have a different function in the cell.
Collapse
Affiliation(s)
- April C Joice
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 39634, USA
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Dodson HC, Morris MT, Morris JC. Glycerol 3-phosphate alters Trypanosoma brucei hexokinase activity in response to environmental change. J Biol Chem 2011; 286:33150-7. [PMID: 21813651 DOI: 10.1074/jbc.m111.235705] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The African trypanosome, Trypanosoma brucei, compartmentalizes some metabolic enzymes within peroxisome-like organelles called glycosomes. The amounts, activities, and types of glycosomal enzymes are modulated coincident with developmental and environmental changes. Pexophagy (fusion of glycosomes with acidic lysosomes) has been proposed to facilitate this glycosome remodeling. Here, we report that, although glycosome-resident enzyme T. brucei hexokinase 1 (TbHK1) protein levels are maintained during pexophagy, acidification inactivates the activity. Glycerol 3-phosphate, which is produced in vivo by a glycosome-resident glycerol kinase, mitigated acid inactivation of lysate-derived TbHK activity. Using recombinant TbHK1, we found that glycerol 3-P influenced enzyme activity at pH 6.5 by preventing substrate and product inhibition by ATP and ADP, respectively. Additionally, TbHK1 inhibition by the flavonol quercetin (QCN) was partially reversed by glycerol 3-P at pH 7.4, whereas at pH 6.5, enzyme activity in the presence of QCN was completely maintained by glycerol 3-P. However, glycerol 3-P did not alter the interaction of QCN with TbHK1, as the lone Trp residue (Trp-177) was quenched under all conditions tested. These findings suggest potential novel mechanisms for the regulation of TbHK1, particularly given the acidification of glycosomes that can be induced under a variety of parasite growth conditions.
Collapse
Affiliation(s)
- Heidi C Dodson
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina 29634, USA
| | | | | |
Collapse
|
35
|
Coley AF, Dodson HC, Morris MT, Morris JC. Glycolysis in the african trypanosome: targeting enzymes and their subcellular compartments for therapeutic development. Mol Biol Int 2011; 2011:123702. [PMID: 22091393 PMCID: PMC3195984 DOI: 10.4061/2011/123702] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Accepted: 02/16/2011] [Indexed: 12/16/2022] Open
Abstract
Subspecies of the African trypanosome, Trypanosoma brucei, which cause human African trypanosomiasis, are transmitted by the tsetse fly, with transmission-essential lifecycle stages occurring in both the insect vector and human host. During infection of the human host, the parasite is limited to using glycolysis of host sugar for ATP production. This dependence on glucose breakdown presents a series of targets for potential therapeutic development, many of which have been explored and validated as therapeutic targets experimentally. These include enzymes directly involved in glucose metabolism (e.g., the trypanosome hexokinases), as well as cellular components required for development and maintenance of the essential subcellular compartments that house the major part of the pathway, the glycosomes.
Collapse
Affiliation(s)
- April F Coley
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
| | | | | | | |
Collapse
|
36
|
Jacobs RT, Nare B, Phillips MA. State of the art in African trypanosome drug discovery. Curr Top Med Chem 2011; 11:1255-74. [PMID: 21401507 PMCID: PMC3101707 DOI: 10.2174/156802611795429167] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 11/25/2010] [Indexed: 11/22/2022]
Abstract
African sleeping sickness is endemic in sub-Saharan Africa where the WHO estimates that 60 million people are at risk for the disease. Human African trypanosomiasis (HAT) is 100% fatal if untreated and the current drug therapies have significant limitations due to toxicity and difficult treatment regimes. No new chemical agents have been approved since eflornithine in 1990. The pentamidine analog DB289, which was in late stage clinical trials for the treatment of early stage HAT recently failed due to toxicity issues. A new protocol for the treatment of late-stage T. brucei gambiense that uses combination nifurtomox/eflornithine (NECT) was recently shown to have better safety and efficacy than eflornithine alone, while being easier to administer. This breakthrough represents the only new therapy for HAT since the approval of eflornithine. A number of research programs are on going to exploit the unusual biochemical pathways in the parasite to identify new targets for target based drug discovery programs. HTS efforts are also underway to discover new chemical entities through whole organism screening approaches. A number of inhibitors with anti-trypanosomal activity have been identified by both approaches, but none of the programs are yet at the stage of identifying a preclinical candidate. This dire situation underscores the need for continued effort to identify new chemical agents for the treatment of HAT.
Collapse
Affiliation(s)
- Robert T. Jacobs
- SCYNEXIS, Inc., Research Triangle Park, North Carolina 27709-2878
| | - Bakela Nare
- SCYNEXIS, Inc., Research Triangle Park, North Carolina 27709-2878
| | - Margaret A. Phillips
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, Texas 75390-9041
| |
Collapse
|
37
|
Dodson HC, Lyda TA, Chambers JW, Morris MT, Christensen KA, Morris JC. Quercetin, a fluorescent bioflavanoid, inhibits Trypanosoma brucei hexokinase 1. Exp Parasitol 2010; 127:423-8. [PMID: 20971104 DOI: 10.1016/j.exppara.2010.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 09/22/2010] [Accepted: 10/14/2010] [Indexed: 12/01/2022]
Abstract
Hexokinases from the African trypanosome, Trypanosoma brucei, are attractive targets for the development of anti-parasitic drugs, in part because the parasite utilizes glycolysis exclusively for ATP production during the mammalian infection. Here, we have demonstrated that the bioflavanoid quercetin (QCN), a known trypanocide, is a mixed inhibitor of Trypanosoma brucei hexokinase 1 (TbHK1) (IC(50) = 4.1 ± 0.8μM). Spectroscopic analysis of QCN binding to TbHK1, taking advantage of the intrinsically fluorescent single tryptophan (Trp177) in TbHK1, revealed that QCN quenches emission of Trp177, which is located near the hinge region of the enzyme. ATP similarly quenched Trp177 emission, while glucose had no impact on fluorescence. Supporting the possibility that QCN toxicity is a consequence of inhibition of the essential hexokinase, in live parasites QCN fluorescence localizes to glycosomes, the subcellular home of TbHK1. Additionally, RNAi-mediated silencing of TbHK1 expression expedited QCN induced death, while over-expressing TbHK1 protected trypanosomes from the compound. In summary, these observations support the suggestion that QCN toxicity is in part attributable to inhibition of the essential TbHK1.
Collapse
Affiliation(s)
- Heidi C Dodson
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
| | | | | | | | | | | |
Collapse
|
38
|
Wang H, Chen XX, Wang LR, Mao YD, Zhou ZM, Sha JH. AF-2364 is a prospective spermicide candidate. Asian J Androl 2010; 12:322-35. [PMID: 20418891 DOI: 10.1038/aja.2010.11] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
AbstractInhibition of sperm motility has recently become a promising target for male contraceptive development. AF-2364, an analogue of Lonidamine (LND), had a contraceptive effect when orally administered to adult Sprague-Dawley rats. LND can also target mitochondria to inhibit oxygen consumption and block energy metabolism in tumour cells. However, there are no reports of the effects of AF-2364 on human sperm function. Herein we describe the action of AF-2364 on human sperm in vitro, as well as the mechanisms involved. AF-2364 specifically blocked human sperm motility in vitro. Further experiments revealed that AF-2364 can target sperm mitochondrial permeability transition (MPT) pores to induce the loss of sperm mitochondrial membrane potential (DeltaPsim) and decrease ATP generation; however, no significant changes in the cytoskeletal network or the human sperm proteome were detected after exposure to AF-2364. Incubation of AF-2364 with other human or mouse cell lines indicated that the spermicidal effect at the lower concentration was specific. In summary, the spermicidal effect of AF-2364 involves direct action on sperm MPT pores, and this compound should be further investigated as a new spermicide candidate.
Collapse
Affiliation(s)
- Hui Wang
- Laboratory of Reproductive Medicine, Department of Histology and Embryology, Nanjing Medical University, Nanjing 210029, China
| | | | | | | | | | | |
Collapse
|
39
|
Sharlow ER, Lyda TA, Dodson HC, Mustata G, Morris MT, Leimgruber SS, Lee KH, Kashiwada Y, Close D, Lazo JS, Morris JC. A target-based high throughput screen yields Trypanosoma brucei hexokinase small molecule inhibitors with antiparasitic activity. PLoS Negl Trop Dis 2010; 4:e659. [PMID: 20405000 PMCID: PMC2854128 DOI: 10.1371/journal.pntd.0000659] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 03/04/2010] [Indexed: 11/18/2022] Open
Abstract
Background The parasitic protozoan Trypanosoma brucei utilizes glycolysis exclusively for ATP production during infection of the mammalian host. The first step in this metabolic pathway is mediated by hexokinase (TbHK), an enzyme essential to the parasite that transfers the γ-phospho of ATP to a hexose. Here we describe the identification and confirmation of novel small molecule inhibitors of bacterially expressed TbHK1, one of two TbHKs expressed by T. brucei, using a high throughput screening assay. Methodology/Principal Findings Exploiting optimized high throughput screening assay procedures, we interrogated 220,233 unique compounds and identified 239 active compounds from which ten small molecules were further characterized. Computation chemical cluster analyses indicated that six compounds were structurally related while the remaining four compounds were classified as unrelated or singletons. All ten compounds were ∼20-17,000-fold more potent than lonidamine, a previously identified TbHK1 inhibitor. Seven compounds inhibited T. brucei blood stage form parasite growth (0.03≤EC50<3 µM) with parasite specificity of the compounds being demonstrated using insect stage T. brucei parasites, Leishmania promastigotes, and mammalian cell lines. Analysis of two structurally related compounds, ebselen and SID 17387000, revealed that both were mixed inhibitors of TbHK1 with respect to ATP. Additionally, both compounds inhibited parasite lysate-derived HK activity. None of the compounds displayed structural similarity to known hexokinase inhibitors or human African trypanosomiasis therapeutics. Conclusions/Significance The novel chemotypes identified here could represent leads for future therapeutic development against the African trypanosome. African sleeping sickness is a disease found in sub-Saharan Africa that is caused by the single-celled parasite Trypanosoma brucei. The drugs used widely now to treat infections are 50 years old and notable for their toxicity, emphasizing the need for development of new therapeutics. In the search for potential drug targets, researchers typically focus on enzymes or proteins that are essential to the survival of the infectious agent while being distinct enough from the host to avoid accidental targeting of the host enzyme. This work describes our research on one such trypanosome enzyme, hexokinase, which is a protein that the parasite requires to make energy. Here we describe the results of our search for inhibitors of the parasite enzyme. By screening 220,223 compounds for anti-hexokinase activity, we have identified new inhibitors of the parasite enzyme. Some of these are toxic to trypanosomes while having no effect on mammalian cells, suggesting that they may hold promise for the development of new anti-parasitic compounds.
Collapse
Affiliation(s)
- Elizabeth R Sharlow
- University of Pittsburgh Drug Discovery Institute and Pittsburgh Molecular Libraries Screening Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Jacobs RT, Ding C. Recent Advances in Drug Discovery for Neglected Tropical Diseases Caused by Infective Kinetoplastid Parasites. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2010. [DOI: 10.1016/s0065-7743(10)45017-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
41
|
Alves-Ferreira M, Guimarães ACR, Capriles PVDSZ, Dardenne LE, Degrave WM. A new approach for potential drug target discovery through in silico metabolic pathway analysis using Trypanosoma cruzi genome information. Mem Inst Oswaldo Cruz 2009; 104:1100-10. [DOI: 10.1590/s0074-02762009000800006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 10/28/2009] [Indexed: 11/22/2022] Open
|
42
|
Cáceres AJ, Michels PAM, Hannaert V. Genetic validation of aldolase and glyceraldehyde-3-phosphate dehydrogenase as drug targets in Trypanosoma brucei. Mol Biochem Parasitol 2009; 169:50-4. [PMID: 19748525 DOI: 10.1016/j.molbiopara.2009.09.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 09/01/2009] [Accepted: 09/02/2009] [Indexed: 10/20/2022]
Abstract
Aldolase (ALD) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of Trypanosoma brucei are considered to be promising targets for chemotherapeutic treatment of African sleeping sickness, because glycolysis is the single source of ATP for the parasite when living in the human bloodstream. Moreover, these enzymes appeared to possess distinct kinetic and structural properties that have already been exploited for the discovery of effective and selective inhibitors with trypanocidal activity. Here we present an experimental, quantitative assessment of the importance of these enzymes for the glycolytic pathway. This was achieved by decreasing the concentrations of ALD and GAPDH by RNA interference. The effects of these knockdowns on parasite growth, levels of various enzymes and transcripts, enzyme activities and glucose consumption were studied. A partial depletion of ALD and GAPDH was already sufficient to rapidly kill the trypanosomes. An effect was also observed on the activity of some other glycolytic enzymes.
Collapse
Affiliation(s)
- Ana Judith Cáceres
- Centro de Ingeniería Genética, Universidad de Los Andes, Mérida, Venezuela
| | | | | |
Collapse
|
43
|
Chambers JW, Kearns MT, Morris MT, Morris JC. Assembly of heterohexameric trypanosome hexokinases reveals that hexokinase 2 is a regulable enzyme. J Biol Chem 2008; 283:14963-70. [PMID: 18387941 DOI: 10.1074/jbc.m802124200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycolysis is essential to Trypanosoma brucei, the protozoan parasite that causes African sleeping sickness in humans and nagana in cattle. Hexokinase (HK), the first enzyme in glycolysis, catalyzes the phosphorylation of glucose to form glucose 6-phosphate. T. brucei harbors two HKs that are 98% identical at the amino acid level, T. brucei hexokinase 1 (TbHK1) and TbHK2. Recombinant TbHK1 (rTbHK1) has HK activity, whereas rTbHK2 does not. Unlike other eukaryotic HKs, TbHK1 is not subject to inhibition by ADP and glucose 6-phosphate. However, TbHK1 is inhibited by myristate, a critical fatty acid in T. brucei biology. We report here that rTbHKs, similar to authentic TbHK, form oligomers. Myristate dissociated these assemblies when incubated with either ATP or glucose. Furthermore, oligomer disruption was reversible by removal of myristate. Mixing of rTbHK1 and rTbHK2 monomers followed by reassembly yielded enzyme with an approximately 3-fold increase in specific activity compared with similarly treated rTbHK1 alone. Surprisingly, reassembly of rTbHK2 with an inactive rTbHK1 variant yielded an active HK, revealing for the first time that rTbHK2 is competent for HK activity. Finally, pyrophosphate inhibits active reassembled rTbHK2 oligomers but not oligomeric rTbHK1, suggesting that the two enzymes have distinct regulatory mechanisms.
Collapse
Affiliation(s)
- Jeremy W Chambers
- Department of Genetics and Biochemistry, Clemson University, 51 New Cherry Street, Clemson, SC 29634, USA
| | | | | | | |
Collapse
|