Gametocytocidal activity of pyronaridine and DNA topoisomerase II inhibitors against multidrug-resistant Plasmodium falciparum in vitro

Chavalitshewinkoon-Petmitr, Porntip; Pongvilairat, Ganokwan; Auparakkitanon, Saranya; Wilairat, Prapon

doi:10.1016/s1383-5769(99)00028-8

Cited by 40 publications

(40 citation statements)

References 10 publications

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“…The recently developed 4-AQ pyronaridine is an inhibitor of P. falciparum topoisomerase II, which is in phase II-III clinical trials in a combined treatment with artesunate (33,34). The in vitro gametocytocidal activity of pyronaridine has been previously reported (35), although recently developed assays revealed that it has high IC 50 s against late-stage gametocytes: 4.26 M (13) and 3.25 M (14). Interestingly, pyronaridine inhibits P. falciparum exflagellation as well as oocyst production (36).…”

Section: Discussionmentioning

confidence: 99%

Imaging-Based High-Throughput Screening Assay To Identify New Molecules with Transmission-Blocking Potential against Plasmodium falciparum Female Gamete Formation

Miguel-Blanco

Lelièvre

Delves

et al. 2015

Antimicrob Agents Chemother

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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 M 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. D espite the efforts made over decades of scientific research, malaria still remains a major health problem in tropical and subtropical areas, with more than 220 million cases and 600,000 deaths being registered per year (1). This parasitic disease is caused by Plasmodium infection through the bite of infected Anopheles female mosquitoes, with Plasmodium falciparum being responsible for the highest mortality rates (2).Traditionally, pharmacological antimalarial treatments have targeted parasite asexual reproduction inside erythrocytes, which leads to the clinical symptoms of malaria. However, a small proportion of these asexual blood stages (0.2 to 1%) are committed to develop into sexual stages: male and female gametocytes (3, 4). Their differentiation process inside erythrocytes takes 8 to 12 days for P. falciparum, and inside erythrocytes they undergo a series of morphological and metabolic changes classically categorized into five stages of maturation (5, 6). While most schizonticides, such as chloroquine, affect young gametocytes (stages I, II, and III), gametocytes at late stages of maturation are not sensitive to them (7). These insensitive stage V gametocytes, which are responsible for ...

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Section: Discussionmentioning

confidence: 99%

Imaging-Based High-Throughput Screening Assay To Identify New Molecules with Transmission-Blocking Potential against Plasmodium falciparum Female Gamete Formation

Miguel-Blanco

Lelièvre

Delves

et al. 2015

Antimicrob Agents Chemother

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“…However, studies that have directly tested the susceptibility of early-stage (I to III) gametocytes to antimalarial compounds and drugs are scarce, and in such studies, the authors have investigated relatively few compounds (15,(18)(19)(20)(21)(22). To the best of our knowledge, our evaluation of 23 reference antimalarial drugs and the screening of the MMV Malaria Box (400 compounds active against asexual blood stages) using the luciferase-based assay described here represents the largest investigation of the chemosensitivity of P. falciparum early gametocytogenesis.…”

Section: Discussionmentioning

confidence: 99%

“…These methods have focused on the later steps of gametocytogenesis and/or on mature gametocytes, as the immature stages have often been hypothesized to be sensitive to most antimalarial drugs and, hence, of limited concern. However, an extensive assessment of the degree of sensitivity of early-stage gametocytes to antimalarial compounds has never been carried out and the few available studies have been limited to a small number of established drugs (15,(18)(19)(20)(21)(22). Furthermore, several early and recent reports suggest that differences exist in the respective chemosensitivity of developing gametocytes and asexual stages to antimalarial compounds such as chloroquine (21), pyrimethamine (21), atovaquone (15,18,22), and methylene blue (15).…”

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confidence: 99%

Identification of MMV Malaria Box Inhibitors of Plasmodium falciparum Early-Stage Gametocytes Using a Luciferase-Based High-Throughput Assay

Lucantoni

Duffy

Adjalley

et al. 2013

Antimicrob Agents Chemother

121

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The design of new antimalarial combinations to treat Plasmodium falciparum infections requires drugs that, in addition to resolving disease symptoms caused by asexual blood stage parasites, can also interrupt transmission to the mosquito vector. Gametocytes, which are essential for transmission, develop as sexual blood stage parasites in the human host over 8 to 12 days and are the most accessible developmental stage for transmission-blocking drugs. Considerable effort is currently being devoted to identifying compounds active against mature gametocytes. However, investigations on the drug sensitivity of developing gametocytes, as well as screening methods for identifying inhibitors of early gametocytogenesis, remain scarce. We have developed a luciferase-based high-throughput screening (HTS) assay using tightly synchronous stage I to III gametocytes from a recombinant P. falciparum line expressing green fluorescent protein (GFP)-luciferase. The assay has been used to evaluate the earlystage gametocytocidal activity of the MMV Malaria Box, a collection of 400 compounds with known antimalarial (asexual blood stage) activity. Screening this collection against early-stage (I to III) gametocytes yielded 64 gametocytocidal compounds with 50% inhibitory concentrations (IC 50 s) below 2.5 M. This assay is reproducible and suitable for the screening of large compound libraries, with an average percent coefficient of variance (%CV) of <5%, an average signal-to-noise ratio (S:N) of >30, and a Z= of ϳ0.8. Our findings highlight the need for screening efforts directed specifically against early gametocytogenesis and indicate the importance of experimental verification of early-stage gametocytocidal activity in the development of new antimalarial candidates for combination therapy. P lasmodium falciparum malaria remains a primary global cause of death and disability from infectious disease, particularly in infants and pregnant women (1). Malaria treatment currently relies on artemisinin-based combination therapy (ACT); however, emerging resistance to artemisinins in the field (2, 3) underscores the need to progress new antimalarial candidates through the drug development pipeline. Recent in vitro high-throughput screening (HTS) campaigns against P. falciparum asexual blood stages, the forms responsible for the clinical manifestations of the disease, have identified a wealth of active chemical classes, representing a promising starting point for the discovery of new therapeutic agents (4-7). The current malaria elimination strategy has also highlighted the need for all new antimalarial combination therapies to include components capable of interrupting the transmission of sexual-stage gametocytes to Anopheles mosquitoes (8, 9). Methods to enable prioritization of inhibitors of the asexual parasite stages based on their additional transmission-blocking activity are therefore urgently required.P. falciparum gametocytes develop through five morphologically distinct stages in the human blood over 8 to 12 days (10) and thereafter ...

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“…Norfloxacin, amsacrine, and etoposide, the DNA topo inhibitors were effective against asexual but not sexual stages of the malaria parasite (Chavalitshewinkoon et al, 2000). Chloroquine, quinine, and related 4-aminoquinolines are effective drugs against malarial infection, and the ability of chloroquine to form complexes with DNA is well documented (Blodgett and Yielding, 1968;Yielding et al, 1971).…”

Section: Resultsmentioning

confidence: 99%

Oxygenated chalcones and bischalcones as a new class of inhibitors of DNA topoisomerase II of malarial parasites

et al. 2007

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The DNA topoisomerase (topo) II of chloroquine-sensitive and chloroquine-resistant strains of the rodent malaria parasite P. berghei were utilized as a target for testing of antimalarial compounds. Compounds belonging to the bischalcone and chalcone series significantly inhibited enzyme activity and percentage parasitaemia of chloroquine-sensitive and chloroquine-resistant strains of P. berghei. Compounds 1a, 1b, 2a, 2b, and 2c showed 100% inhibition while compounds 2h and 2i showed 60% and 63% inhibition of topoisomerase II activity of the chloroquinesensitive strain, respectively. Compounds 2a, 2b, and 2d significantly inhibited the topo II activity of chloroquine-resistant strain. Compounds 2g and 2e specifically inhibited the topo II activity of the chloroquine-resistant strain of P. berghei with no effect on the chloroquine-sensitive strain. The in vitro topo II inhibition by chalcone and bischalcone analogs can be correlated with their in vivo antimalarial activity, as compounds 2c and 2h inhibited both in vitro activity of topo II and in vivo parasitaemia of the chloroquine-sensitive strain of P. berghei. In the chloroquine-resistant strain, compounds 2c, 2e, 2g, and 2i inhibited activity against both in vitro topo II and parasitaemia in vivo. The significant inhibition of topo II in the chloroquine-resistant strain by some of the analogs suggests the utilization of these structures for the synthesis of compounds active against chloroquine-resistant malarial parasites.

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Gametocytocidal activity of pyronaridine and DNA topoisomerase II inhibitors against multidrug-resistant Plasmodium falciparum in vitro

Cited by 40 publications

References 10 publications

Imaging-Based High-Throughput Screening Assay To Identify New Molecules with Transmission-Blocking Potential against Plasmodium falciparum Female Gamete Formation

Imaging-Based High-Throughput Screening Assay To Identify New Molecules with Transmission-Blocking Potential against Plasmodium falciparum Female Gamete Formation

Identification of MMV Malaria Box Inhibitors of Plasmodium falciparum Early-Stage Gametocytes Using a Luciferase-Based High-Throughput Assay

Oxygenated chalcones and bischalcones as a new class of inhibitors of DNA topoisomerase II of malarial parasites

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