1
|
Rifaldi, Fadlan A, Fatmawati S, Purnomo AS, Ersam T. Antiplasmodial and anticancer activities of xanthones isolated from Garcinia bancana Miq. Nat Prod Res 2024; 38:885-890. [PMID: 37029625 DOI: 10.1080/14786419.2023.2199212] [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: 09/29/2022] [Accepted: 03/28/2023] [Indexed: 04/09/2023]
Abstract
This report describes the isolation and characterization of xanthones from Garcinia bancana Miq. and evaluates their antiplasmodial and anticancer activities. Macluraxanthone (1), isojacareubin (2), and gerontoxanthone C (3) were isolated from the stem bark of G. bancana Miq. for the first time. In silico molecular docking studies revealed the hydrogen bonding and steric interactions between xanthones (1-3) and PfLDH/VEGFR2. The in vitro antiplasmodial activity was assayed against the chloroquine-sensitive Plasmodium falciparum strain 3D7 by the lactate dehydrogenase (LDH) method. The anticancer evaluation was evaluated against the A549, MCF-7, HeLa, and B-16 cancer cell lines. Compounds (1) (IC50 8.45-16.71 μM) and (3) (IC50 9.69-14.86 μM) showed more potent anticancer activity than compound (2) (IC50 25.46-31.31 μM), as well for their antiplasmodial activity (4.28 μM, 5.52 μM, 11.45 μM). Our findings indicated the potential of G. bancana Miq. as a natural resource of antiplasmodial and anticancer compounds.
Collapse
Affiliation(s)
| | - Arif Fadlan
- Department of Chemistry, Faculty of Science and Data Analytics, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
| | - Sri Fatmawati
- Department of Chemistry, Faculty of Science and Data Analytics, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
| | - Adi Setyo Purnomo
- Department of Chemistry, Faculty of Science and Data Analytics, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
| | - Taslim Ersam
- Department of Chemistry, Faculty of Science and Data Analytics, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
| |
Collapse
|
2
|
Chemical and Pharmacological Properties of Decoquinate: A Review of Its Pharmaceutical Potential and Future Perspectives. Pharmaceutics 2022; 14:pharmaceutics14071383. [PMID: 35890280 PMCID: PMC9315532 DOI: 10.3390/pharmaceutics14071383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/16/2022] Open
Abstract
Decoquinate (DQ) is an antimicrobial agent commonly used as a feed additive for birds for human consumption. Its use as an additive is well established, but DQ has the potential for therapy as an antimicrobial drug for veterinary treatment and its optimized derivatives and/or formulations, mainly nanoformulations, have antimicrobial activity against pathogens that infect humans. However, DQ has a high partition coefficient and low solubility in aqueous fluids, and these biopharmaceutical properties have limited its use in humans. In this review, we highlight the antimicrobial activity and pharmacokinetic properties of DQ and highlight the solutions currently under investigation to overcome these drawbacks. A literature search was conducted focusing on the use of decoquinate against various infectious diseases in humans and animals. The search was conducted in several databases, including scientific and patent databases. Pharmaceutical nanotechnology and medicinal chemistry are the tools of choice to achieve human applications, and most of these applications have been able to improve the biopharmaceutical properties and pharmacokinetic profile of DQ. Based on the results presented here, DQ prototypes could be tested in clinical trials for human application in the coming years.
Collapse
|
3
|
Studies of Potency and Efficacy of an Optimized Artemisinin-Quinoline Hybrid against Multiple Stages of the Plasmodium Life Cycle. Pharmaceuticals (Basel) 2021; 14:ph14111129. [PMID: 34832911 PMCID: PMC8620906 DOI: 10.3390/ph14111129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 11/23/2022] Open
Abstract
A recently developed artemisinin-quinoline hybrid, named 163A, has been shown to display potent activity against the asexual blood stage of Plasmodium, the malaria parasite. In this study, we determined its in vitro cytotoxicity to mammalian cells, its potency to suppress P. berghei hepatic infection and to decrease the viability of P. falciparum gametocytes, in addition to determining whether the drug exhibits efficacy of a P. berghei infection in mice. This hybrid compound has a low level of cytotoxicity to mammalian cells and, conversely, a high level of selectivity. It is potent in the prevention of hepatic stage development as well as in killing gametocytes, denoting a potential blockage of malaria transmission. The hybrid presents a potent inhibitory activity for beta-hematin crystal formation, in which subsequent assays revealed that its endoperoxide component undergoes bioactivation by reductive reaction with ferrous heme towards the formation of heme-drug adducts; in parallel, the 7-chloroquinoline component has binding affinity for ferric hemin. Both structural components of the hybrid co-operate to enhance the inhibition of beta-hematin, and this bitopic ligand property is essential for arresting the growth of asexual blood parasites. We demonstrated the in vivo efficacy of the hybrid as an erythrocytic schizonticide agent in comparison to a chloroquine/artemisinin combination therapy. Collectively, the findings suggest that the bitopic property of the hybrid is highly operative on heme detoxification suppression, and this provides compelling evidence for explaining the action of the hybrid on the asexual blood stage. For sporozoite and gametocyte stages, the hybrid conserves the potency typically observed for endoperoxide drugs, and this is possibly achieved due to the redox chemistry of endoperoxide components with ferrous heme.
Collapse
|
4
|
Erhunse N, Sahal D. Protecting future antimalarials from the trap of resistance: Lessons from artemisinin-based combination therapy (ACT) failures. J Pharm Anal 2021; 11:541-554. [PMID: 34765267 PMCID: PMC8572664 DOI: 10.1016/j.jpha.2020.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 07/19/2020] [Accepted: 07/19/2020] [Indexed: 11/01/2022] Open
Abstract
Having faced increased clinical treatment failures with dihydroartemisinin-piperaquine (DHA-PPQ), Cambodia swapped the first line artemisinin-based combination therapy (ACT) from DHA-PPQ to artesunate-mefloquine given that parasites resistant to piperaquine are susceptible to mefloquine. However, triple mutants have now emerged, suggesting that drug rotations may not be adequate to keep resistance at bay. There is, therefore, an urgent need for alternative treatment strategies to tackle resistance and prevent its spread. A proper understanding of all contributors to artemisinin resistance may help us identify novel strategies to keep artemisinins effective until new drugs become available for their replacement. This review highlights the role of the key players in artemisinin resistance, the current strategies to deal with it and suggests ways of protecting future antimalarial drugs from bowing to resistance as their predecessors did.
Collapse
Affiliation(s)
- Nekpen Erhunse
- Malaria Drug Discovery Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
- Department of Biochemistry, Faculty of Life Sciences, University of Benin, Benin City, Edo-State, Nigeria
| | - Dinkar Sahal
- Malaria Drug Discovery Research Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| |
Collapse
|
5
|
Yaméogo KB, Yerbanga RS, Ouattara SB, Yao FA, Lefèvre T, Zongo I, Nikièma F, Compaoré YD, Tinto H, Chandramohan D, Greenwood B, Belem AMG, Cohuet A, Ouédraogo JB. Effect of seasonal malaria chemoprevention plus azithromycin on Plasmodium falciparum transmission: gametocyte infectivity and mosquito fitness. Malar J 2021; 20:326. [PMID: 34315475 PMCID: PMC8314489 DOI: 10.1186/s12936-021-03855-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 07/16/2021] [Indexed: 11/24/2022] Open
Abstract
Background Seasonal malaria chemoprevention (SMC) consists of administration of sulfadoxine-pyrimethamine (SP) + amodiaquine (AQ) at monthly intervals to children during the malaria transmission period. Whether the addition of azithromycin (AZ) to SMC could potentiate the benefit of the intervention was tested through a double-blind, randomized, placebo-controlled trial. The effect of SMC and the addition of AZ, on malaria transmission and on the life history traits of Anopheles gambiae mosquitoes have been investigated. Methods The study included 438 children randomly selected from among participants in the SMC + AZ trial and 198 children from the same area who did not receive chemoprevention. For each participant in the SMC + AZ trial, blood was collected 14 to 21 days post treatment, examined for the presence of malaria sexual and asexual stages and provided as a blood meal to An. gambiae females using a direct membrane-feeding assay. Results The SMC treatment, with or without AZ, significantly reduced the prevalence of asexual Plasmodium falciparum (LRT X22 = 69, P < 0.0001) and the gametocyte prevalence (LRT X22 = 54, P < 0.0001). In addition, the proportion of infectious feeds (LRT X22 = 61, P < 0.0001) and the prevalence of oocysts among exposed mosquitoes (LRT X22 = 22.8, P < 0.001) was reduced when mosquitoes were fed on blood from treated children compared to untreated controls. The addition of AZ to SPAQ was associated with an increased proportion of infectious feeds (LRT X21 = 5.2, P = 0.02), suggesting a significant effect of AZ on gametocyte infectivity. There was a slight negative effect of SPAQ and SPAQ + AZ on mosquito survival compared to mosquitoes fed with blood from control children (LRTX22 = 330, P < 0.0001). Conclusion This study demonstrates that SMC may contribute to a reduction in human to mosquito transmission of P. falciparum, and the reduced mosquito longevity observed for females fed on treated blood may increase the benefit of this intervention in control of malaria. The addition of AZ to SPAQ in SMC appeared to enhance the infectivity of gametocytes providing further evidence that this combination is not an appropriate intervention.
Collapse
Affiliation(s)
- Koudraogo Bienvenue Yaméogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso. .,Université Nazi Boni, Bobo-Dioulasso, Burkina Faso.
| | - Rakiswendé Serge Yerbanga
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,Institut des Sciences et Techniques (INSTech Bobo), BP2779, Bobo-Dioulasso, Burkina Faso
| | | | - Franck A Yao
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Thierry Lefèvre
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France.,Laboratoire Mixte International Sur Les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso.,Centre de Recherche en Écologie et Évolution de la Santé (CREES), Montpellier, France
| | - Issaka Zongo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Frederic Nikièma
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | | | - Halidou Tinto
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | | | | | | | - Anna Cohuet
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France.,Laboratoire Mixte International Sur Les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
| | - Jean Bosco Ouédraogo
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,Institut des Sciences et Techniques (INSTech Bobo), BP2779, Bobo-Dioulasso, Burkina Faso
| |
Collapse
|
6
|
Chellan P, Avery VM, Duffy S, Land KM, Tam CC, Kim JH, Cheng LW, Romero-Canelón I, Sadler PJ. Bioactive half-sandwich Rh and Ir bipyridyl complexes containing artemisinin. J Inorg Biochem 2021; 219:111408. [PMID: 33826972 DOI: 10.1016/j.jinorgbio.2021.111408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/21/2021] [Accepted: 02/21/2021] [Indexed: 02/06/2023]
Abstract
Reaction of dihydroartemisinin (DHA) with 4-methyl-4'-carboxy-2,2'-bipyridine yielded the new ester derivative L1. Six novel organometallic half-sandwich chlorido Rh(III) and Ir(III) complexes (1-6) containing pentamethylcyclopentadienyl, (Cp*), tetramethylphenylcyclopentadienyl (Cpxph), or tetramethylbiphenylcyclopentadienyl (Cpxbiph), and N,N-chelated bipyridyl group of L1, have been synthesized and characterized. The complexes were screened for inhibitory activity against the Plasmodium falciparum 3D7 (sensitive), Dd2 (multi-drug resistant) and NF54 late stage gametocytes (LSGNF54), the parasite strain Trichomonas vaginalis G3, as well as A2780 (human ovarian carcinoma), A549 (human alveolar adenocarcinoma), HCT116 (human colorectal carcinoma), MCF7 (human breast cancer) and PC3 (human prostate cancer) cancer cell lines. They show nanomolar antiplasmodial activity, outperforming chloroquine and artemisinin. Their activities were also comparable to dihydroartemisinin. As anticancer agents, several of the complexes showed high inhibitory effects, with Ir(III) complex 3, containing the tetramethylbiphenylcyclopentadienyl ligand, having similar IC50 values (concentration for 50% of maximum inhibition of cell growth) as the clinical drug cisplatin (1.06-9.23 μM versus 0.24-7.2 μM, respectively). Overall, the iridium complexes (1-3) are more potent compared to the rhodium derivatives (4-6), and complex 3 emerges as the most promising candidate for future studies.
Collapse
Affiliation(s)
- Prinessa Chellan
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Vicky M Avery
- Discovery Biology, Griffith University, Nathan, Queensland 4111, Australia
| | - Sandra Duffy
- Discovery Biology, Griffith University, Nathan, Queensland 4111, Australia
| | - Kirkwood M Land
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, United States of America
| | - Christina C Tam
- Foodborne Toxin Detection and Prevention Research Unit, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, United States of America
| | - Jong H Kim
- Foodborne Toxin Detection and Prevention Research Unit, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, United States of America
| | - Luisa W Cheng
- Foodborne Toxin Detection and Prevention Research Unit, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, United States of America
| | | | - Peter J Sadler
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK.
| |
Collapse
|
7
|
Siddiqui AJ, Adnan M, Jahan S, Redman W, Saeed M, Patel M. Neurological disorder and psychosocial aspects of cerebral malaria: what is new on its pathogenesis and complications? A minireview. Folia Parasitol (Praha) 2020; 67. [PMID: 32636351 DOI: 10.14411/fp.2020.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 03/06/2020] [Indexed: 01/21/2023]
Abstract
Recently, malaria is remain considered as the most prevalent infectious disease, affecting the human health globally. High morbidity and mortality worldwide is often allied with cerebral malaria (CM) based disorders of the central nervous system, especially across many tropical and sub-tropical regions. These disorders are characterised by the infection of Plasmodium species, which leads to acute or chronic neurological disorders, even after having active/effective antimalarial drugs. Furthermore, even during the treatment, individual remain sensitive for neurological impairments in the form of decrease blood flow and vascular obstruction in brain including many more other changes. This review briefly explains and update on the epidemiology, burden of disease, pathogenesis and role of CM in neurological disorders with behaviour and function in mouse and human models. Moreover, the social stigma, which plays an important role in neurological disorders and a factor for assessing CM, is also discussed in this review.
Collapse
Affiliation(s)
| | | | - Sadaf Jahan
- Department of Medical Laboratory, College of Applied Medical Sciences, Majmaah University, Majmaah city, Saudi Arabia
| | - Whitni Redman
- Surgery Department, Division of Biomedical Research, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Mοhd Saeed
- Department of Biology, College of Science, University of Hail, Hail, PO Box 2440, Saudi Arabia
| | - Mitesh Patel
- Bapalal Vaidya Botanical Research Centre, Department of Biosciences, Veer Narmad South Gujarat University, Surat, Gujarat, India
| |
Collapse
|
8
|
Significant Efficacy of a Single Low Dose of Primaquine Compared to Stand-Alone Artemisinin Combination Therapy in Reducing Gametocyte Carriage in Cambodian Patients with Uncomplicated Multidrug-Resistant Plasmodium falciparum Malaria. Antimicrob Agents Chemother 2020; 64:AAC.02108-19. [PMID: 32179526 PMCID: PMC7269483 DOI: 10.1128/aac.02108-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/06/2020] [Indexed: 11/22/2022] Open
Abstract
Since 2012, a single low dose of primaquine (SLDPQ; 0.25 mg/kg of body weight) with artemisinin-based combination therapies has been recommended as the first-line treatment of acute uncomplicated Plasmodium falciparum malaria to interrupt its transmission, especially in low-transmission settings of multidrug resistance, including artemisinin resistance. Policy makers in Cambodia have been reluctant to implement this recommendation due to primaquine safety concerns and a lack of data on its efficacy. Since 2012, a single low dose of primaquine (SLDPQ; 0.25 mg/kg of body weight) with artemisinin-based combination therapies has been recommended as the first-line treatment of acute uncomplicated Plasmodium falciparum malaria to interrupt its transmission, especially in low-transmission settings of multidrug resistance, including artemisinin resistance. Policy makers in Cambodia have been reluctant to implement this recommendation due to primaquine safety concerns and a lack of data on its efficacy. In this randomized controlled trial, 109 Cambodians with acute uncomplicated P. falciparum malaria received dihydroartemisinin-piperaquine (DP) alone or combined with SLDPQ on the first treatment day. The transmission-blocking efficacy of SLDPQ was evaluated on days 0, 1, 2, 3, 7, 14, 21, and 28, and recrudescence by reverse transcriptase PCR (RT-PCR) (gametocyte prevalence) and membrane feeding assays with Anopheles minimus mosquitoes (gametocyte infectivity). Without the influence of recrudescent infections, DP-SLDPQ reduced gametocyte carriage 3-fold compared to that achieved with DP. Of 48 patients tested on day 0, only 3 patients were infectious to mosquitoes (∼6%). Posttreatment, three patients were infectious on day 14 (3.5%, 1/29) and on the 1st and 7th days of recrudescence (8.3%, 1/12 for each); this overall low infectivity precluded our ability to assess its transmission-blocking efficacy. Our study confirms the effective gametocyte clearance of SLDPQ when combined with DP in multidrug-resistant P. falciparum infections and the negative impact of recrudescent infections due to poor DP efficacy. Artesunate-mefloquine (ASMQ) has replaced DP, and ASMQ-SLDPQ has been deployed to treat all patients with symptomatic P. falciparum infections to further support the elimination of multidrug-resistant P. falciparum in Cambodia. (This study has been registered at ClinicalTrials.gov under identifier NCT02434952.)
Collapse
|
9
|
Yadav DK, Kumar S, Teli MK, Yadav R, Chaudhary S. Molecular Targets for Malarial Chemotherapy: A Review. Curr Top Med Chem 2019; 19:861-873. [DOI: 10.2174/1568026619666190603080000] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 11/22/2022]
Abstract
The malaria parasite resistance to the existing drugs is a serious problem to the currently used
antimalarials and, thus, highlights the urgent need to develop new and effective anti-malarial molecules.
This could be achieved either by the identification of the new drugs for the validated targets or by further
refining/improving the existing antimalarials; or by combining previously effective agents with
new/existing drugs to have a synergistic effect that counters parasite resistance; or by identifying novel
targets for the malarial chemotherapy. In this review article, a comprehensive collection of some of the
novel molecular targets has been enlisted for the antimalarial drugs. The targets which could be deliberated
for developing new anti-malarial drugs could be: membrane biosynthesis, mitochondrial system,
apicoplasts, parasite transporters, shikimate pathway, hematin crystals, parasite proteases, glycolysis,
isoprenoid synthesis, cell cycle control/cycline dependent kinase, redox system, nucleic acid metabolism,
methionine cycle and the polyamines, folate metabolism, the helicases, erythrocyte G-protein, and
farnesyl transferases. Modern genomic tools approaches such as structural biology and combinatorial
chemistry, novel targets could be identified followed by drug development for drug resistant strains providing
wide ranges of novel targets in the development of new therapy. The new approaches and targets
mentioned in the manuscript provide a basis for the development of new unique strategies for antimalarial
therapy with limited off-target effects in the near future.
Collapse
Affiliation(s)
- Dharmendra K. Yadav
- College of Pharmacy, Gachon University of Medicine and Science, Hambakmoeiro, 191, Yeonsu-gu, Incheon 406-799, South Korea
| | - Surendra Kumar
- College of Pharmacy, Gachon University of Medicine and Science, Hambakmoeiro, 191, Yeonsu-gu, Incheon 406-799, South Korea
| | - Mahesh K. Teli
- College of Pharmacy, Gachon University of Medicine and Science, Hambakmoeiro, 191, Yeonsu-gu, Incheon 406-799, South Korea
| | - Ravikant Yadav
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology, Jawaharlal Nehru Marg, Jaipur-302017, India
| | - Sandeep Chaudhary
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology, Jawaharlal Nehru Marg, Jaipur-302017, India
| |
Collapse
|
10
|
Paloque L, Witkowski B, Lelièvre J, Ouji M, Ben Haddou T, Ariey F, Robert A, Augereau JM, Ménard D, Meunier B, Benoit-Vical F. Endoperoxide-based compounds: cross-resistance with artemisinins and selection of a Plasmodium falciparum lineage with a K13 non-synonymous polymorphism. J Antimicrob Chemother 2019; 73:395-403. [PMID: 29177421 DOI: 10.1093/jac/dkx412] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/09/2017] [Indexed: 11/12/2022] Open
Abstract
Background Owing to the emergence of multiresistant Plasmodium falciparum parasites in Southeast Asia, along with the impressive decrease in the efficacy of the endoperoxide compound artemisinin and of artemisinin-based combination therapies, the development of novel antimalarial drugs or combinations is required. Although several antiplasmodial molecules, such as endoperoxide-based compounds, are in advanced research or development, we do not know whether resistance to artemisinin derivatives might impact the efficacy of these new compounds. Objectives To address this issue, the antiplasmodial efficacy of trioxaquines, hybrid endoperoxide-based molecules, was explored, along with their ability to select in vitro resistant parasites under discontinuous and dose-escalating drug pressure. Methods The in vitro susceptibilities of artemisinin- and trioxaquine-resistant laboratory strains and recent Cambodian field isolates were evaluated by different phenotypic and genotypic assays. Results Trioxaquines tested presented strong cross-resistance with artemisinin both in the artemisinin-resistant laboratory F32-ART5 line and in Cambodian field isolates. Trioxaquine drug pressure over 4 years led to the in vitro selection of the F32-DU line, which is resistant to trioxaquine and artemisinin, similar to the F32-ART lineage. F32-DU whole genome sequencing (WGS) revealed that resistance to trioxaquine was associated with the same non-synonymous mutation in the propeller domain of the K13 protein (M476I) that was found in the F32-ART lineage. Conclusions These worrisome results indicate the risk of cross-resistance between artemisinins and endoperoxide-based antiplasmodial drugs in the development of the K13 mutant parasites and question the usefulness of these molecules in the future therapeutic arsenal.
Collapse
Affiliation(s)
- Lucie Paloque
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| | - Benoit Witkowski
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France.,Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Joël Lelièvre
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| | - Manel Ouji
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| | - Tanila Ben Haddou
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| | - Frédéric Ariey
- INSERM 1016, Institut Cochin, Université Paris Descartes et Service de Parasitologie-Mycologie Hôpital Cochin, Paris
| | - Anne Robert
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| | - Jean-Michel Augereau
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| | - Didier Ménard
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Bernard Meunier
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| | - Françoise Benoit-Vical
- CNRS; LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, F-31077 Toulouse, France.,Université de Toulouse; UPS, INPT; LCC, F-31077 Toulouse, France
| |
Collapse
|
11
|
Kalaria PN, Karad SC, Raval DK. A review on diverse heterocyclic compounds as the privileged scaffolds in antimalarial drug discovery. Eur J Med Chem 2018; 158:917-936. [PMID: 30261467 DOI: 10.1016/j.ejmech.2018.08.040] [Citation(s) in RCA: 167] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/18/2018] [Accepted: 08/14/2018] [Indexed: 12/11/2022]
Abstract
The upward extend of malaria collectively with the emergence of resistance against predictable drugs has put enormous pressure on public health systems to introduce new malaria treatments. Heterocycles play an important role in the design and discovery of new malaria active compounds. Heterocyclic compounds have attracted significant attention for malaria treatment because of simplicity of parallelization and the examining power with regard to chemical space. Introduction of a variety of heterocyclic compounds have enabled to maintain the high levels of antimalarial potency observed for other more lipophilic analogues whilst improving the solubility and the oral bioavailability in pre-clinical species. In this review, we present an overview of recent literature to provide imminent into the applications of different heterocyclic scaffolds in fighting against malaria.
Collapse
Affiliation(s)
- Piyush N Kalaria
- Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar, 388120, Gujarat, India.
| | - Sharad C Karad
- Department of Chemistry, Marwadi University, Rajkot, Gujarat, India.
| | - Dipak K Raval
- Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar, 388120, Gujarat, India.
| |
Collapse
|
12
|
Ouji M, Augereau JM, Paloque L, Benoit-Vical F. Plasmodium falciparum resistance to artemisinin-based combination therapies: A sword of Damocles in the path toward malaria elimination. ACTA ACUST UNITED AC 2018; 25:24. [PMID: 29676250 PMCID: PMC5909375 DOI: 10.1051/parasite/2018021] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/15/2018] [Indexed: 01/28/2023]
Abstract
The use of artemisinin-based combination therapies (ACTs), which combine an artemisinin derivative with a partner drug, in the treatment of uncomplicated malaria has largely been responsible for the significant reduction in malaria-related mortality in tropical and subtropical regions. ACTs have also played a significant role in the 18% decline in the incidence of malaria cases from 2010 to 2016. However, this progress is seriously threatened by the reduced clinical efficacy of artemisinins, which is characterised by delayed parasitic clearance and a high rate of recrudescence, as reported in 2008 in Western Cambodia. Resistance to artemisinins has already spread to several countries in Southeast Asia. Furthermore, resistance to partner drugs has been shown in some instances to be facilitated by pre-existing decreased susceptibility to the artemisinin component of the ACT. A major concern is not only the spread of these multidrug-resistant parasites to the rest of Asia but also their possible appearance in Sub-Saharan Africa, the continent most affected by malaria, as has been the case in the past with parasite resistance to other antimalarial treatments. It is therefore essential to understand the acquisition of resistance to artemisinins by Plasmodium falciparum to adapt malaria treatment policies and to propose new therapeutic solutions.
Collapse
Affiliation(s)
- Manel Ouji
- LCC (Laboratoire de Chimie de Coordination du CNRS), BP 44099, 205 Route de Narbonne, 31077 Toulouse cedex 4, France - Université de Toulouse; UPS, INPT; LCC; F-31077 Toulouse, France
| | - Jean-Michel Augereau
- LCC (Laboratoire de Chimie de Coordination du CNRS), BP 44099, 205 Route de Narbonne, 31077 Toulouse cedex 4, France - Université de Toulouse; UPS, INPT; LCC; F-31077 Toulouse, France
| | - Lucie Paloque
- LCC (Laboratoire de Chimie de Coordination du CNRS), BP 44099, 205 Route de Narbonne, 31077 Toulouse cedex 4, France - Université de Toulouse; UPS, INPT; LCC; F-31077 Toulouse, France
| | - Françoise Benoit-Vical
- LCC (Laboratoire de Chimie de Coordination du CNRS), BP 44099, 205 Route de Narbonne, 31077 Toulouse cedex 4, France - Université de Toulouse; UPS, INPT; LCC; F-31077 Toulouse, France
| |
Collapse
|
13
|
Mina JGM, Denny PW. Everybody needs sphingolipids, right! Mining for new drug targets in protozoan sphingolipid biosynthesis. Parasitology 2018; 145:134-147. [PMID: 28637533 PMCID: PMC5964470 DOI: 10.1017/s0031182017001081] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 05/15/2017] [Accepted: 05/18/2017] [Indexed: 12/18/2022]
Abstract
Sphingolipids (SLs) are an integral part of all eukaryotic cellular membranes. In addition, they have indispensable functions as signalling molecules controlling a myriad of cellular events. Disruption of either the de novo synthesis or the degradation pathways has been shown to have detrimental effects. The earlier identification of selective inhibitors of fungal SL biosynthesis promised potent broad-spectrum anti-fungal agents, which later encouraged testing some of those agents against protozoan parasites. In this review we focus on the key enzymes of the SL de novo biosynthetic pathway in protozoan parasites of the Apicomplexa and Kinetoplastidae, outlining the divergence and interconnection between host and pathogen metabolism. The druggability of the SL biosynthesis is considered, alongside recent technology advances that will enable the dissection and analyses of this pathway in the parasitic protozoa. The future impact of these advances for the development of new therapeutics for both globally threatening and neglected infectious diseases is potentially profound.
Collapse
Affiliation(s)
- John G M Mina
- Department of Biosciences,Lower Mountjoy,Stockton Road,Durham DH1 3LE,UK
| | - P W Denny
- Department of Biosciences,Lower Mountjoy,Stockton Road,Durham DH1 3LE,UK
| |
Collapse
|
14
|
Li H, Sun W, Huang X, Lu X, Patel PR, Kim M, Orr MJ, Fisher RM, Tanaka TQ, McKew JC, Simeonov A, Sanderson PE, Zheng W, Williamson KC, Huang W. Efficient Synthesis of 1,9-Substituted Benzo[h][1,6]naphthyridin-2(1H)-ones and Evaluation of their Plasmodium falciparum Gametocytocidal Activities. ACS COMBINATORIAL SCIENCE 2017; 19:748-754. [PMID: 29024590 DOI: 10.1021/acscombsci.7b00119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel three-component, two-step, one-pot nucleophilic aromatic substitution (SNAr)-intramolecular cyclization-Suzuki coupling reaction was developed for the synthesis of benzo[h][1,6]naphthyridin-2(1H)-ones (Torins). On the basis of the new efficiently convergent synthetic route, a library of Torin analogs was synthesized. The antimalarial activities of these compounds were evaluated against asexual parasites using a growth inhibition assay and gametocytes using a viability assay.
Collapse
Affiliation(s)
- Hao Li
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Wei Sun
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Xiuli Huang
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Xiao Lu
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Paresma R. Patel
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Myunghoon Kim
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Meghan J. Orr
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Richard M. Fisher
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Takeshi Q Tanaka
- Laboratory
of Malaria and Vector Research, National Institute of Allergy and
Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - John C. McKew
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Anton Simeonov
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Philip E. Sanderson
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Wei Zheng
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kim C. Williamson
- Department
of Biology, Loyola University Chicago, Chicago, Illinois 60660, United States
- Microbiology
and Immunology Department, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, United States
| | - Wenwei Huang
- National
Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| |
Collapse
|
15
|
Bahamontes-Rosa N, Gomez-Lorenzo MG, Lelièvre J, Rodriguez Alejandre A, Almela MJ, Lozano S, Herreros E, Gamo FJ. A novel validated assay to support the discovery of new anti-malarial gametocytocidal agents. Malar J 2016; 15:385. [PMID: 27448565 PMCID: PMC4957904 DOI: 10.1186/s12936-016-1429-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/05/2016] [Indexed: 11/21/2022] Open
Abstract
Background Drugs that kill or inhibit Plasmodium gametocytes in the human host could potentially synergize the impact of other chemotherapeutic interventions by blocking transmission. To develop such agents, reliable methods are needed to study the in vitro activity of compounds against gametocytes. This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of Plasmodium falciparum gametocyte development using real-time PCR (qPCR). Methods Genes previously reported to be transcribed at the different sexual stages of the gametocytogenesis were selected for study and their mRNA expression was measured in a gametocytogenesis course by qPCR. Genes mainly expressed in the later stages of gametocyte development were used as a surrogate measurement of drug activity. To distinguish between cidal and static drug effects, two different experiments were performed in parallel, one with constant drug pressure throughout the experiment (144 h), and another in which the gametocyte cultures were exposed to the compound for only 48 h. Results Four P.falciparum genes coding for proteins Pf77, ROM3, Pfs25, and Pfg377 with transcription specific for late-stage gametocyte development were identified. The in vitro anti-malarial activity of compounds against such gametocytes was assessed by measuring mRNA levels of these genes using qPCR. The assay was validated against standard anti-malarial drugs (epoxomicin, dihydroartemisinin, chloroquine, thiostrepton, and methylene blue) and compounds from the GSK compound library with known anti-gametocyte activity. Conclusions This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of P. falciparum gametocyte development using qPCR in genetically unmodified parasites. The method described is a reliable and user-friendly technique with a medium throughput that could be easily implemented in any laboratory. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1429-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Noemí Bahamontes-Rosa
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain.
| | - María G Gomez-Lorenzo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Joël Lelièvre
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Ane Rodriguez Alejandre
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - María Jesus Almela
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Sonia Lozano
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Esperanza Herreros
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Francisco-Javier Gamo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| |
Collapse
|
16
|
D'Alessandro S, Camarda G, Corbett Y, Siciliano G, Parapini S, Cevenini L, Michelini E, Roda A, Leroy D, Taramelli D, Alano P. A chemical susceptibility profile of the Plasmodium falciparum transmission stages by complementary cell-based gametocyte assays. J Antimicrob Chemother 2016; 71:1148-58. [PMID: 26888912 DOI: 10.1093/jac/dkv493] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/19/2015] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES As most available antimalarial drugs are ineffective against the Plasmodium falciparum transmission stages, new drugs against the parasite's gametocytes are urgently needed to combat malaria globally. The unique biology of gametocytes requires assays that need to be specific, to faithfully monitor anti-gametocyte activity, and to be easy to perform, cheap and scalable to high-throughput screening (HTS). METHODS We developed an HTS cell-based assay with P. falciparum gametocytes specifically expressing a potent luciferase. To confirm HTS hit activity for several parasite genotypes, the luciferase assay and the gametocyte lactate dehydrogenase (LDH) assay, usable on any parasite isolate, were compared by screening antimalarial drugs and determining IC50 values of anti-gametocyte hits from the 'Malaria Box' against early- and late-stage gametocytes. RESULTS Comparison of the two assays, conducted on the early and on late gametocyte stages, revealed an excellent correlation (R(2) > 0.9) for the IC50 values obtained by the respective readouts. Differences in susceptibility to drugs and compounds between the two parasite developmental stages were consistently measured in both assays. CONCLUSIONS This work indicates that the luciferase and gametocyte LDH assays are interchangeable and that their specific advantages can be exploited to design an HTS pipeline leading to new transmission-blocking compounds. Results from these assays consistently defined a gametocyte chemical susceptibility profile, relevant to the planning of future drug discovery strategies.
Collapse
Affiliation(s)
- Sarah D'Alessandro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Grazia Camarda
- Dipartimento di Malattie Infettive, Parassitarie, Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | - Yolanda Corbett
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Giulia Siciliano
- Dipartimento di Malattie Infettive, Parassitarie, Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | - Silvia Parapini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Luca Cevenini
- Dipartimento di Chimica 'G. Ciamician', Università di Bologna, Bologna, Italy
| | - Elisa Michelini
- Dipartimento di Chimica 'G. Ciamician', Università di Bologna, Bologna, Italy Istituto Nazionale Biostrutture e Biosistemi (INBB), Roma, Italy
| | - Aldo Roda
- Dipartimento di Chimica 'G. Ciamician', Università di Bologna, Bologna, Italy Istituto Nazionale Biostrutture e Biosistemi (INBB), Roma, Italy
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Donatella Taramelli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie, Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| |
Collapse
|
17
|
An assay to probe Plasmodium falciparum growth, transmission stage formation and early gametocyte development. Nat Protoc 2015; 10:1131-42. [PMID: 26134953 DOI: 10.1038/nprot.2015.072] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Conversion from asexual proliferation to sexual differentiation initiates the production of the gametocyte, which is the malaria parasite stage required for human-to-mosquito transmission. This protocol describes an assay designed to probe the effect of drugs or other perturbations on asexual replication, sexual conversion and early gametocyte development in the major human malaria parasite Plasmodium falciparum. Synchronized asexually replicating parasites are induced for gametocyte production by the addition of conditioned medium, and they are then exposed to the treatment of interest during sexual commitment or at any subsequent stage of early gametocyte development. Flow cytometry is used to measure asexual proliferation and gametocyte production via DNA dye staining and the gametocyte-specific expression of a fluorescent protein, respectively. This screening approach may be used to identify and evaluate potential transmission-blocking compounds and to further investigate the mechanism of sexual conversion in malaria parasites. The full protocol can be completed in 11 d.
Collapse
|
18
|
Reader J, Botha M, Theron A, Lauterbach SB, Rossouw C, Engelbrecht D, Wepener M, Smit A, Leroy D, Mancama D, Coetzer TL, Birkholtz LM. Nowhere to hide: interrogating different metabolic parameters of Plasmodium falciparum gametocytes in a transmission blocking drug discovery pipeline towards malaria elimination. Malar J 2015; 14:213. [PMID: 25994518 PMCID: PMC4449569 DOI: 10.1186/s12936-015-0718-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/22/2015] [Indexed: 12/23/2022] Open
Abstract
Background The discovery of malaria transmission-blocking compounds is seen as key to malaria elimination strategies and gametocyte-screening platforms are critical filters to identify active molecules. However, unlike asexual parasite assays measuring parasite proliferation, greater variability in end-point readout exists between different gametocytocidal assays. This is compounded by difficulties in routinely producing viable, functional and stage-specific gametocyte populations. Here, a parallel evaluation of four assay platforms on the same gametocyte populations was performed for the first time. This allowed the direct comparison of the ability of different assay platforms to detect compounds with gametocytocidal activity and revealed caveats in some assay readouts that interrogate different parasite biological functions. Methods Gametocytogenesis from Plasmodium falciparum (NF54) was optimized with a robust and standardized protocol. ATP, pLDH, luciferase reporter and PrestoBlue® assays were compared in context of a set of 10 reference compounds. The assays were performed in parallel on the same gametocyte preparation (except for luciferase reporter lines) using the same drug preparations (48 h). The remaining parameters for each assay were all comparable. Results A highly robust method for generating viable and functional gametocytes was developed and comprehensively validated resulting in an average gametocytaemia of 4 %. Subsequent parallel assays for gametocytocidal activity indicated that different assay platforms were not able to screen compounds with variant chemical scaffolds similarly. Luciferase reporter assays revealed that synchronized stage-specific gametocyte production is essential for drug discovery, as differential susceptibility in various gametocyte developmental populations is evident. Conclusions With this study, the key parameters for assays aiming at testing the gametocytocidal activity of potential transmission blocking molecules against Plasmodium gametocytes were accurately dissected. This first and uniquely comparative study emphasizes differential effects seen with the use of different assay platforms interrogating variant biological systems. Whilst this data is informative from a biological perspective and may provide indications of the drug mode of action, it does highlight the care that must be taken when screening broad-diversity chemotypes with a single assay platform against gametocytes for which the biology is not clearly understood. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0718-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Janette Reader
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Mariëtte Botha
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Anjo Theron
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, South Africa.
| | - Sonja B Lauterbach
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Claire Rossouw
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, South Africa.
| | - Dewaldt Engelbrecht
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Melanie Wepener
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Annél Smit
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland.
| | - Dalu Mancama
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, South Africa.
| | - Theresa L Coetzer
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Lyn-Marie Birkholtz
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| |
Collapse
|
19
|
Rebelo M, Tempera C, Bispo C, Andrade C, Gardner R, Shapiro HM, Hänscheid T. Light depolarization measurements in malaria: A new job for an old friend. Cytometry A 2015; 87:437-45. [PMID: 25808846 DOI: 10.1002/cyto.a.22659] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/28/2015] [Accepted: 02/27/2015] [Indexed: 12/15/2022]
Abstract
The use of flow cytometry in malaria research has increased over the last decade. Most approaches use nucleic acid stains to detect parasite DNA and RNA and require complex multi-color, multi-parameter analysis to reliably detect infected red blood cells (iRBCs). We recently described a novel and simpler approach to parasite detection based on flow cytometric measurement of scattered light depolarization caused by hemozoin (Hz), a pigment formed by parasite digestion of hemoglobin in iRBCs. Depolarization measurement by flow cytometry was described in 1987; however, patent issues restricted its use to a single manufacturer's hematology analyzers until 2009. Although we recently demonstrated that depolarization measurement of Hz, easily implemented on a bench top flow cytometer (Cyflow), provided useful information for malaria work, doubts regarding its application and utility remain in both the flow cytometry and malaria communities, at least in part because instrument manufacturers do not offer the option of measuring depolarized scatter. Under such circumstances, providing other researchers with guidance as to how to do this seemed to offer the most expeditious way to resolve the issue. We accordingly examined how several commercially available flow cytometers (CyFlow SL, MoFLo, Attune and Accuri C6) could be modified to detect depolarization due to the presence of free Hz on solution, or of Hz in leukocytes or erythrocytes from rodent or human blood. All were readily adapted, with substantially equivalent results obtained with lasers emitting over a wide wavelength range. Other instruments now available may also be modifiable for Hz measurement. Cytometric detection of Hz using depolarization is useful to study different aspects of malaria. Adding additional parameters, such as DNA content and base composition and RNA content, can demonstrably provide improved accuracy and sensitivity of parasite detection and characterization, allowing malaria researchers and eventually clinicians to benefit from cytometric technology.
Collapse
Affiliation(s)
- Maria Rebelo
- Molecular Microbiology and Infection Unit, Instituto De Medicina Molecular, Faculdade De Medicina, Lisbon, Portugal
| | | | | | | | | | | | | |
Collapse
|
20
|
Imaging-based high-throughput screening assay to identify new molecules with transmission-blocking potential against Plasmodium falciparum female gamete formation. Antimicrob Agents Chemother 2015; 59:3298-305. [PMID: 25801574 DOI: 10.1128/aac.04684-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/16/2015] [Indexed: 11/20/2022] Open
Abstract
In response to a call for the global eradication of malaria, drug discovery has recently been extended to identify compounds that prevent the onward transmission of the parasite, which is mediated by Plasmodium falciparum stage V gametocytes. Lately, metabolic activity has been used in vitro as a surrogate for gametocyte viability; however, as gametocytes remain relatively quiescent at this stage, their ability to undergo onward development (gamete formation) may be a better measure of their functional viability. During gamete formation, female gametocytes undergo profound morphological changes and express translationally repressed mRNA. By assessing female gamete cell surface expression of one such repressed protein, Pfs25, as the readout for female gametocyte functional viability, we developed an imaging-based high-throughput screening (HTS) assay to identify transmission-blocking compounds. This assay, designated the P. falciparum female gametocyte activation assay (FGAA), was scaled up to a high-throughput format (Z' factor, 0.7 ± 0.1) and subsequently validated using a selection of 50 known antimalarials from diverse chemical families. Only a few of these agents showed submicromolar 50% inhibitory concentrations in the assay: thiostrepton, methylene blue, and some endoperoxides. To determine the best conditions for HTS, a robustness test was performed with a selection of the GlaxoSmithKline Tres Cantos Antimalarial Set (TCAMS) and the final screening conditions for this library were determined to be a 2 μM concentration and 48 h of incubation with gametocytes. The P. falciparum FGAA has been proven to be a robust HTS assay faithful to Plasmodium transmission-stage cell biology, and it is an innovative useful tool for antimalarial drug discovery which aims to identify new molecules with transmission-blocking potential.
Collapse
|
21
|
Rodrigues CAB, Frade RFM, Albuquerque IS, Perry MJ, Gut J, Machado M, Rosenthal PJ, Prudêncio M, Afonso CAM, Moreira R. Targeting the Erythrocytic and Liver Stages of Malaria Parasites withs-Triazine-Based Hybrids. ChemMedChem 2015; 10:883-90. [DOI: 10.1002/cmdc.201500011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 02/15/2015] [Indexed: 11/08/2022]
|
22
|
Jones RA, Panda SS, Hall CD. Quinine conjugates and quinine analogues as potential antimalarial agents. Eur J Med Chem 2015; 97:335-55. [PMID: 25683799 DOI: 10.1016/j.ejmech.2015.02.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 01/08/2015] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
Abstract
Malaria is a tropical disease, prevalent in Southeast Asia and Africa, resulting in over half a million deaths annually; efforts to develop new antimalarial agents are therefore particularly important. Quinine continues to play a role in the fight against malaria, but quinoline derivatives are more widely used. Drugs based on the quinoline scaffold include chloroquine and primaquine, which are able to act against the blood and liver stages of the parasite's life cycle. The purpose of this review is to discuss reported biologically active compounds based on either the quinine or quinoline scaffold that may have enhanced antimalarial activity. The review emphasises hybrid molecules, and covers advances made in the last five years. The review is divided into three sections: modifications to the quinine scaffold, modifications to aminoquinolines and finally metal-containing antimalarial compounds.
Collapse
Affiliation(s)
- Rachel A Jones
- Center for Heterocyclic Compounds, University of Florida, Department of Chemistry, Gainesville, FL 32611-7200, USA.
| | - Siva S Panda
- Center for Heterocyclic Compounds, University of Florida, Department of Chemistry, Gainesville, FL 32611-7200, USA
| | - C Dennis Hall
- Center for Heterocyclic Compounds, University of Florida, Department of Chemistry, Gainesville, FL 32611-7200, USA
| |
Collapse
|
23
|
Potent Plasmodium falciparum gametocytocidal activity of diaminonaphthoquinones, lead antimalarial chemotypes identified in an antimalarial compound screen. Antimicrob Agents Chemother 2014; 59:1389-97. [PMID: 25512421 DOI: 10.1128/aac.01930-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Forty percent of the world's population is threatened by malaria, which is caused by Plasmodium parasites and results in an estimated 200 million clinical cases and 650,000 deaths each year. Drug resistance has been reported for all commonly used antimalarials and has prompted screens to identify new drug candidates. However, many of these new candidates have not been evaluated against the parasite stage responsible for transmission, gametocytes. If Plasmodium falciparum gametocytes are not eliminated, patients continue to spread malaria for weeks after asexual parasite clearance. Asymptomatic individuals can also harbor gametocyte burdens sufficient for transmission, and a safe, effective gametocytocidal agent could also be used in community-wide malaria control programs. Here, we identify 15 small molecules with nanomolar activity against late-stage gametocytes. Fourteen are diaminonaphthoquinones (DANQs), and one is a 2-imino-benzo[d]imidazole (IBI). One of the DANQs identified, SJ000030570, is a lead antimalarial candidate. In contrast, 94% of the 650 compounds tested are inactive against late-stage gametocytes. Consistent with the ineffectiveness of most approved antimalarials against gametocytes, of the 19 novel compounds with activity against known anti-asexual-stage targets, only 3 had any strong effect on gametocyte viability. These data demonstrate the distinct biology of the transmission stages and emphasize the importance of screening for gametocytocidal activity. The potent gametocytocidal activity of DANQ and IBI coupled with their efficacy against asexual parasites provides leads for the development of antimalarials with the potential to prevent both the symptoms and the spread of malaria.
Collapse
|
24
|
Antimalarial activity of the myxobacterial macrolide chlorotonil a. Antimicrob Agents Chemother 2014; 58:6378-84. [PMID: 25114138 DOI: 10.1128/aac.03326-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myxobacteria are Gram-negative soil-dwelling bacteria belonging to the phylum Proteobacteria. They are a rich source of promising compounds for clinical application, such as epothilones for cancer therapy and several new antibiotics. In the course of a bioactivity screening program of secondary metabolites produced by Sorangium cellulosum strains, the macrolide chlorotonil A was found to exhibit promising antimalarial activity. Subsequently, we evaluated chlorotonil A against Plasmodium falciparum laboratory strains and clinical isolates from Gabon. Chlorotonil A was highly active, with a 50% inhibitory concentration between 4 and 32 nM; additionally, no correlations between the activities of chlorotonil A and artesunate (rho, 0.208) or chloroquine (rho, -0.046) were observed. Per os treatment of Plasmodium berghei-infected mice with four doses of as little as 36 mg of chlorotonil A per kg of body weight led to the suppression of parasitemia with no obvious signs of toxicity. Chlorotonil A acts against all stages of intraerythrocytic parasite development, including ring-stage parasites and stage IV to V gametocytes, and it requires only a very short exposure to the parasite to exert its antimalarial action. Conclusively, chlorotonil A has an exceptional and unprecedented profile of action and represents an urgently required novel antimalarial chemical scaffold. Therefore, we propose it as a lead structure for further development as an antimalarial chemotherapeutic.
Collapse
|
25
|
Hansen FK, Sumanadasa SDM, Stenzel K, Duffy S, Meister S, Marek L, Schmetter R, Kuna K, Hamacher A, Mordmüller B, Kassack MU, Winzeler EA, Avery VM, Andrews KT, Kurz T. Discovery of HDAC inhibitors with potent activity against multiple malaria parasite life cycle stages. Eur J Med Chem 2014; 82:204-13. [PMID: 24904967 DOI: 10.1016/j.ejmech.2014.05.050] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/12/2014] [Accepted: 05/21/2014] [Indexed: 10/25/2022]
Abstract
In this work we investigated the antiplasmodial activity of a series of HDAC inhibitors containing an alkoxyamide connecting-unit linker region. HDAC inhibitor 1a (LMK235), previously shown to be a novel and specific inhibitor of human HDAC4 and 5, was used as a starting point to rapidly construct a mini-library of HDAC inhibitors using a straightforward solid-phase supported synthesis. Several of these novel HDAC inhibitors were found to have potent in vitro activity against asexual stage Plasmodium falciparum malaria parasites. Representative compounds were shown to hyperacetylate P. falciparum histones and to inhibit deacetylase activity of recombinant PfHDAC1 and P. falciparum nuclear extracts. All compounds were also screened in vitro for activity against Plasmodium berghei exo-erythrocytic stages and selected compounds were further tested against late stage (IV and V) P. falciparum gametocytes. Of note, some compounds showed nanomolar activity against all three life cycle stages tested (asexual, exo-erythrocytic and gametocyte stages) and several compounds displayed significantly increased parasite selectivity compared to the reference HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). These data suggest that it may be possible to develop HDAC inhibitors that target multiple malaria parasite life cycle stages.
Collapse
Affiliation(s)
- Finn K Hansen
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Subathdrage D M Sumanadasa
- Eskitis Institute for Drug Discovery, Don Young Road, Nathan Campus, Griffith University, QLD 4111, Australia
| | - Katharina Stenzel
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Sandra Duffy
- Eskitis Institute for Drug Discovery, Don Young Road, Nathan Campus, Griffith University, QLD 4111, Australia
| | - Stephan Meister
- Department of Pediatrics, University of California, San Diego, School of Medicine, 9500 Gilman Drive 0741, La Jolla, CA 92093, USA
| | - Linda Marek
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Rebekka Schmetter
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Krystina Kuna
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Alexandra Hamacher
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstr. 27, 72074 Tübingen, Germany; Medical Research Laboratory, Albert Schweitzer Hospital, Lambaréné, Gabon
| | - Matthias U Kassack
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Elizabeth A Winzeler
- Department of Pediatrics, University of California, San Diego, School of Medicine, 9500 Gilman Drive 0741, La Jolla, CA 92093, USA
| | - Vicky M Avery
- Eskitis Institute for Drug Discovery, Don Young Road, Nathan Campus, Griffith University, QLD 4111, Australia
| | - Katherine T Andrews
- Eskitis Institute for Drug Discovery, Don Young Road, Nathan Campus, Griffith University, QLD 4111, Australia.
| | - Thomas Kurz
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
| |
Collapse
|
26
|
Cloete TT, de Kock C, Smith PJ, N'Da DD. Synthesis, in vitro antiplasmodial activity and cytotoxicity of a series of artemisinin–triazine hybrids and hybrid-dimers. Eur J Med Chem 2014; 76:470-81. [DOI: 10.1016/j.ejmech.2014.01.040] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 01/15/2014] [Accepted: 01/18/2014] [Indexed: 12/11/2022]
|
27
|
|
28
|
Chemical signatures and new drug targets for gametocytocidal drug development. Sci Rep 2014; 4:3743. [PMID: 24434750 PMCID: PMC3894558 DOI: 10.1038/srep03743] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/20/2013] [Indexed: 01/14/2023] Open
Abstract
Control of parasite transmission is critical for the eradication of malaria. However, most antimalarial drugs are not active against P. falciparum gametocytes, responsible for the spread of malaria. Consequently, patients can remain infectious for weeks after the clearance of asexual parasites and clinical symptoms. Here we report the identification of 27 potent gametocytocidal compounds (IC50 < 1 μM) from screening 5,215 known drugs and compounds. All these compounds were active against three strains of gametocytes with different drug sensitivities and geographical origins, 3D7, HB3 and Dd2. Cheminformatic analysis revealed chemical signatures for P. falciparum sexual and asexual stages indicative of druggability and suggesting potential targets. Torin 2, a top lead compound (IC50 = 8 nM against gametocytes in vitro), completely blocked oocyst formation in a mouse model of transmission. These results provide critical new leads and potential targets to expand the repertoire of malaria transmission-blocking reagents.
Collapse
|
29
|
Antiapicoplast and gametocytocidal screening to identify the mechanisms of action of compounds within the malaria box. Antimicrob Agents Chemother 2013; 58:811-9. [PMID: 24247137 DOI: 10.1128/aac.01500-13] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Malaria remains a significant infectious disease that causes millions of clinical cases and >800,000 deaths per year. The Malaria Box is a collection of 400 commercially available chemical entities that have antimalarial activity. The collection contains 200 drug-like compounds, based on their oral absorption and the presence of known toxicophores, and 200 probe-like compounds, which are intended to represent a broad structural diversity. These compounds have confirmed activities against the asexual intraerythrocytic stages of Plasmodium falciparum and low cytotoxicities, but their mechanisms of action and their activities in other stages of the parasite's life cycle remain to be determined. The apicoplast is considered to be a promising source of malaria-specific targets, and its main function during intraerythrocytic stages is to provide the isoprenoid precursor isopentenyl diphosphate, which can be used for phenotype-based screens to identify compounds targeting this organelle. We screened 400 compounds from the Malaria Box using apicoplast-targeting phenotypic assays to identify their potential mechanisms of action. We identified one compound that specifically targeted the apicoplast. Further analyses indicated that the molecular target of this compound may differ from those of the current antiapicoplast drugs, such as fosmidomycin. Moreover, in our efforts to elucidate the mechanisms of action of compounds from the Malaria Box, we evaluated their activities against other stages of the life cycle of the parasite. Gametocytes are the transmission stage of the malaria parasite and are recognized as a priority target in efforts to eradicate malaria. We identified 12 compounds that were active against gametocytes with 50% inhibitory concentration values of <1 μM.
Collapse
|
30
|
Kanishchev OS, Lavoignat A, Picot S, Médebielle M, Bouillon JP. New route to the 5-((arylthio- and heteroarylthio)methylene)-3-(2,2,2-trifluoroethyl)-furan-2(5H)-ones—Key intermediates in the synthesis of 4-aminoquinoline γ-lactams as potent antimalarial compounds. Bioorg Med Chem Lett 2013; 23:6167-71. [DOI: 10.1016/j.bmcl.2013.08.108] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/27/2013] [Accepted: 08/29/2013] [Indexed: 11/24/2022]
|
31
|
Held J, Kreidenweiss A, Mordmüller B. Novel approaches in antimalarial drug discovery. Expert Opin Drug Discov 2013; 8:1325-37. [PMID: 24090219 DOI: 10.1517/17460441.2013.843522] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION The development of new antimalarial drugs remains of the utmost importance, since Plasmodium falciparum has developed resistance against nearly all chemotherapeutics in clinical use. In an effort to contain the resistance of P. falciparum against artemisinins and to further eradication efforts, studies are ongoing to identify novel and more efficacious approaches to develop antimalarials. AREAS COVERED The authors review the classical and new approaches to antimalarial drug discovery, with a special emphasis on the various stages of the parasite's life cycle and the different Plasmodium species. The authors discuss the methodologies and strategies for early efficacy testing that aim to narrow down the portfolio of promising compounds. EXPERT OPINION The increased efforts in the discovery and development of new antimalarial compounds have led to the recognition of new promising hits. However, there is still major roadblock of selecting the most promising compounds and then further testing them in early clinical trials, especially in the current restricted economy. Controlled human malaria infection has much potential for speeding-up the early development process of many drug candidates including those which target the pre-erythrocytic stages.
Collapse
Affiliation(s)
- Jana Held
- University of Tübingen, Institute of Tropical Medicine , Wilhelmstraße 27, D-72074 Tübingen , Germany +49 7071 29 82364 ; +49 7071 295189 ;
| | | | | |
Collapse
|
32
|
Gorka AP, Jacobs LM, Roepe PD. Cytostatic versus cytocidal profiling of quinoline drug combinations via modified fixed-ratio isobologram analysis. Malar J 2013; 12:332. [PMID: 24044530 PMCID: PMC3874740 DOI: 10.1186/1475-2875-12-332] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/18/2013] [Indexed: 01/13/2023] Open
Abstract
Background Drug combination therapy is the frontline of malaria treatment. There is an ever-accelerating need for new, efficacious combination therapies active against drug resistant malaria. Proven drugs already in the treatment pipeline, such as the quinolines, are important components of current combination therapy and also present an attractive test bank for rapid development of new concepts. Methods The efficacy of several drug combinations versus chloroquine-sensitive and chloroquine-resistant strains was measured using both cytostatic and cytocidal potency assays. Conclusions These screens identify quinoline and non-quinoline pairs that exhibit synergy, additivity, or antagonism using the fixed-ratio isobologram method and find tafenoquine – methylene blue combination to be the most synergistic. Also, interestingly, for selected pairs, additivity, synergy, or antagonism defined by quantifying IC50 (cytostatic potency) does not necessarily predict similar behaviour when potency is defined by LD50 (cytocidal potency). These data further support an evolving new model for quinoline anti-malarials, wherein haem and haemozoin are the principle target for cytostatic activity, but may not be the only target relevant for cytocidal activity.
Collapse
Affiliation(s)
- Alexander P Gorka
- Department of Chemistry, Department of Biochemistry, Cellular, & Molecular Biology, and Center for Infectious Disease, Georgetown University, 37th and 'O' Sts, NW, Washington, DC, 20057, USA.
| | | | | |
Collapse
|
33
|
Abstract
Drugs that kill or inhibit the sexual stages of Plasmodium in order to prevent transmission are important components of malaria control programmes. Reducing gametocyte carriage is central to the control of Plasmodium falciparum transmission as infection can result in extended periods of gametocytaemia. Unfortunately the number of drugs with activity against gametocytes is limited. Primaquine is currently the only licensed drug with activity against the sexual stages of malaria parasites and its use is hampered by safety concerns. This shortcoming is likely the result of the technical challenges associated with gametocyte studies together with the focus of previous drug discovery campaigns on asexual parasite stages. However recent emphasis on malaria eradication has resulted in an upsurge of interest in identifying compounds with activity against gametocytes. This review examines the gametocytocidal properties of currently available drugs as well as those in the development pipeline and examines the prospects for discovery of new anti-gametocyte compounds.
Collapse
|
34
|
Biamonte MA, Wanner J, Le Roch KG. Recent advances in malaria drug discovery. Bioorg Med Chem Lett 2013; 23:2829-43. [PMID: 23587422 PMCID: PMC3762334 DOI: 10.1016/j.bmcl.2013.03.067] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/11/2013] [Accepted: 03/20/2013] [Indexed: 01/18/2023]
Abstract
This digest covers some of the most relevant progress in malaria drug discovery published between 2010 and 2012. There is an urgent need to develop new antimalarial drugs. Such drugs can target the blood stage of the disease to alleviate the symptoms, the liver stage to prevent relapses, and the transmission stage to protect other humans. The pipeline for the blood stage is becoming robust, but this should not be a source of complacency, as the current therapies set a high standard. Drug discovery efforts directed towards the liver and transmission stages are in their infancy but are receiving increasing attention as targeting these stages could be instrumental in eradicating malaria.
Collapse
Affiliation(s)
- Marco A Biamonte
- Drug Discovery for Tropical Diseases, Suite 230, San Diego, CA 92121, USA.
| | | | | |
Collapse
|
35
|
D'Alessandro S, Silvestrini F, Dechering K, Corbett Y, Parapini S, Timmerman M, Galastri L, Basilico N, Sauerwein R, Alano P, Taramelli D. A Plasmodium falciparum screening assay for anti-gametocyte drugs based on parasite lactate dehydrogenase detection. J Antimicrob Chemother 2013; 68:2048-58. [PMID: 23645588 DOI: 10.1093/jac/dkt165] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES Plasmodium gametocytes, responsible for malaria parasite transmission from humans to mosquitoes, represent a crucial target for new antimalarial drugs to achieve malaria elimination/eradication. We developed a novel colorimetric screening method for anti-gametocyte compounds based on the parasite lactate dehydrogenase (pLDH) assay, already standardized for asexual stages, to measure gametocyte viability and drug susceptibility. METHODS Gametocytogenesis of 3D7 and NF54 Plasmodium falciparum strains was induced in vitro and asexual parasites were depleted with N-acetylglucosamine. Gametocytes were treated with dihydroartemisinin, epoxomicin, methylene blue, primaquine, puromycin or chloroquine in 96-well plates and the pLDH activity was evaluated using a modified Makler protocol. Mosquito infectivity was measured by the standard membrane feeding assay (SMFA). RESULTS A linear correlation was found between gametocytaemia determined by Giemsa staining and pLDH activity. A concentration-dependent reduction in pLDH activity was observed after 72 h of drug treatment, whereas an additional 72 h of incubation without drugs was required to obtain complete inhibition of gametocyte viability. SMFA on treated and control gametocytes confirmed that a reduction in pLDH activity translates into reduced oocyst development in the mosquito vector. CONCLUSIONS The gametocyte pLDH assay is fast, easy to perform, cheap and reproducible and is suitable for screening novel transmission-blocking compounds, which does not require parasite transgenic lines.
Collapse
Affiliation(s)
- Sarah D'Alessandro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|