Browse
Submit Data
Databases
API
Help

Dataset Information

18 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

In vitro selection predicts malaria parasite resistance to dihydroorotate dehydrogenase inhibitors in a mouse infection model.

ABSTRACT: Resistance has developed in Plasmodium malaria parasites to every antimalarial drug in clinical use, prompting the need to characterize the pathways mediating resistance. Here, we report a framework for assessing development of resistance of Plasmodium falciparum to new antimalarial therapeutics. We investigated development of resistance by P. falciparum to the dihydroorotate dehydrogenase (DHODH) inhibitors DSM265 and DSM267 in tissue culture and in a mouse model of P. falciparum infection. We found that resistance to these drugs arose rapidly both in vitro and in vivo. We identified 13 point mutations mediating resistance in the parasite DHODH in vitro that overlapped with the DHODH mutations that arose in the mouse infection model. Mutations in DHODH conferred increased resistance (ranging from 2- to ~400-fold) to DHODH inhibitors in P. falciparum in vitro and in vivo. We further demonstrated that the drug-resistant parasites carrying the C276Y mutation had mitochondrial energetics comparable to the wild-type parasite and also retained their fitness in competitive growth experiments. Our data suggest that in vitro selection of drug-resistant P. falciparum can predict development of resistance in a mouse model of malaria infection.

SUBMITTER: Mandt REK

PROVIDER: S-EPMC7444640 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Triazolopyrimidine-based dihydroorotate dehydrogenase inhibitors with potent and selective activity against the malaria parasite Plasmodium falciparum.

Project description:A Plasmodium falciparum dihydroorotate dehydrogenase ( PfDHODH) inhibitor that is potent ( KI = 15 nM) and species-selective (>5000-fold over the human enzyme) was identified by high-throughput screening. The substituted triazolopyrimidine and its structural analogues were produced by an inexpensive three-step synthesis, and the series showed good association between PfDHODH inhibition and parasite toxicity. This study has identified the first nanomolar PfDHODH inhibitor with potent antimalarial activity in whole cells (EC50 = 79 nM).

| S-EPMC2624570 | biostudies-literature

Identification of New Human Malaria Parasite Plasmodium falciparum Dihydroorotate Dehydrogenase Inhibitors by Pharmacophore and Structure-Based Virtual Screening.

Project description:Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH), a key enzyme in the de novo pyrimidine biosynthesis pathway, which the Plasmodium falciparum relies on exclusively for survival, has emerged as a promising target for antimalarial drugs. In an effort to discover new and potent PfDHODH inhibitors, 3D-QSAR pharmacophore models were developed based on the structures of known PfDHODH inhibitors and the validated Hypo1 model was used as a 3D search query for virtual screening of the National Cancer Institute database. The virtual hit compounds were further filtered based on molecular docking and Molecular Mechanics/Generalized Born Surface Area binding energy calculations. The combination of the pharmacophore and structure-based virtual screening resulted in the identification of nine new compounds that showed >25% inhibition of PfDHODH at a concentration of 10 ?M, three of which exhibited IC50 values in the range of 0.38-20 ?M. The most active compound, NSC336047, displayed species-selectivity for PfDHODH over human DHODH and inhibited parasite growth with an IC50 of 26 ?M. In addition to this, 13 compounds inhibited parasite growth with IC50 values of ? 50 ?M, 4 of which showed IC50 values in the range of 5-12 ?M. These compounds could be further explored in the identification and development of more potent PfDHODH and parasite growth inhibitors.

| S-EPMC4871132 | biostudies-literature

Optimization of Potent Inhibitors of P. falciparum Dihydroorotate Dehydrogenase for the Treatment of Malaria.

Project description:Inhibition of dihydroorotate dehydrogenase (DHODH) for P. falciparum potentially represents a new treatment option for malaria, since DHODH catalyzes the rate-limiting step in the pyrimidine biosynthetic pathway and P. falciparum is unable to salvage pyrimidines and must rely on de novo biosynthesis for survival. We report herein the synthesis and structure-activity relationship of a series of 5-(2-methylbenzimidazol-1-yl)-N-alkylthiophene-2-carboxamides that are potent inhibitors against PfDHODH but do not inhibit the human enzyme. On the basis of efficacy observed in three mouse models of malaria, acceptable safety pharmacology risk assessment and safety toxicology profile in rodents, lack of potential drug-drug interactions, acceptable ADME/pharmacokinetic profile, and projected human dose, 5-(4-cyano-2-methyl-1H-benzo[d]imidazol-1-yl)-N-cyclopropylthiophene-2-carboxamide 2q was identified as a potential drug development candidate.

| S-EPMC4018051 | biostudies-literature

Novel inhibitors of Plasmodium falciparum dihydroorotate dehydrogenase with anti-malarial activity in the mouse model.

Project description:Plasmodium falciparum, the causative agent of the most deadly form of human malaria, is unable to salvage pyrimidines and must rely on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHODH) catalyzes the rate-limiting step in the pyrimidine biosynthetic pathway and represents a potential target for anti-malarial therapy. A high throughput screen and subsequent medicinal chemistry program identified a series of N-alkyl-5-(1H-benzimidazol-1-yl)thiophene-2-carboxamides with low nanomolar in vitro potency against DHODH from P. falciparum, P. vivax, and P. berghei. The compounds were selective for the parasite enzymes over human DHODH, and x-ray structural data on the analog Genz-667348, demonstrated that species selectivity could be attributed to amino acid differences in the inhibitor-binding site. Compounds from this series demonstrated in vitro potency against the 3D7 and Dd2 strains of P. falciparum, good tolerability and oral exposure in the mouse, and ED(50) values in the 4-day murine P. berghei efficacy model of 13-21 mg/kg/day with oral twice-daily dosing. In particular, treatment with Genz-667348 at 100 mg/kg/day resulted in sterile cure. Two recent analogs of Genz-667348 are currently undergoing pilot toxicity testing to determine suitability as clinical development candidates.

| S-EPMC2963363 | biostudies-literature

In vitro resistance selections for Plasmodium falciparum dihydroorotate dehydrogenase inhibitors give mutants with multiple point mutations in the drug-binding site and altered growth.

Project description:Malaria is a preventable and treatable disease; yet half of the world's population lives at risk of infection, and an estimated 660,000 people die of malaria-related causes every year. Rising drug resistance threatens to make malaria untreatable, necessitating both the discovery of new antimalarial agents and the development of strategies to identify and suppress the emergence and spread of drug resistance. We focused on in-development dihydroorotate dehydrogenase (DHODH) inhibitors. Characterizing resistance pathways for antimalarial agents not yet in clinical use will increase our understanding of the potential for resistance. We identified resistance mechanisms of Plasmodium falciparum (Pf) DHODH inhibitors via in vitro resistance selections. We found 11 point mutations in the PfDHODH target. Target gene amplification and unknown mechanisms also contributed to resistance, albeit to a lesser extent. These mutant parasites were often hypersensitive to other PfDHODH inhibitors, which immediately suggested a novel combination therapy approach to preventing resistance. Indeed, a combination of wild-type and mutant-type selective inhibitors led to resistance far less often than either drug alone. The effects of point mutations in PfDHODH were corroborated with purified recombinant wild-type and mutant-type PfDHODH proteins, which showed the same trends in drug response as the cognate cell lines. Comparative growth assays demonstrated that two mutant parasites grew less robustly than their wild-type parent, and the purified protein of those mutants showed a decrease in catalytic efficiency, thereby suggesting a reason for the diminished growth rate. Co-crystallography of PfDHODH with three inhibitors suggested that hydrophobic interactions are important for drug binding and selectivity.

| S-EPMC4140291 | biostudies-literature

The Dihydroorotate Dehydrogenase Inhibitor Brequinar Is Synergistic with ENT1/2 Inhibitors.

Project description:The dihydroorotate dehydrogenase (DHODH) inhibitor brequinar failed all clinical trials for solid tumors. To investigate mechanisms to increase brequinar's efficacy, we employed a combination strategy to simultaneously inhibit the nucleotide salvage pathways. Brequinar is synergistic with the equilibrative nucleoside transporter (ENT) inhibitor dipyridamole, but not the concentrative nucleoside transporter inhibitor phlorizin. This synergy carries over to ENT1/2 inhibition, but not ENT4. Our previously described brequinar analogue 41 was also synergistic with dipyridamole as were the FDA-approved DHODH inhibitors leflunomide and teriflunomide but the latter required much higher concentrations than brequinar. Therefore, a combination of brequinar and ENT inhibitors presents a potential anti-cancer strategy in select tumors.

| S-EPMC7737209 | biostudies-literature

Identification of Collateral Sensitivity to Dihydroorotate Dehydrogenase Inhibitors in Plasmodium falciparum.

Project description:Drug resistance has been reported for every antimalarial in use highlighting the need for new strategies to protect the efficacy of therapeutics in development. We have previously shown that resistance can be suppressed with a population biology trap: by identifying situations where resistance to one compound confers hypersensitivity to another (collateral sensitivity), we can design combination therapies that not only kill the parasite but also guide its evolution away from resistance. We applied this concept to the Plasmodium falciparum dihydroorotate dehydrogenase ( PfDHODH) enzyme, a well validated antimalarial target with inhibitors in the development pipeline. Here, we report a high-throughput screen to identify compounds specifically active against PfDHODH resistant mutants. We additionally perform extensive cross-resistance profiling allowing us to identify compound pairs demonstrating the potential for mutually incompatible resistance. These combinations represent promising starting points for exploiting collateral sensitivity to extend the useful lifespan of new antimalarial therapeutics.

| S-EPMC5899019 | biostudies-literature

Structural plasticity of malaria dihydroorotate dehydrogenase allows selective binding of diverse chemical scaffolds.

Project description:Malaria remains a major global health burden and current drug therapies are compromised by resistance. Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) was validated as a new drug target through the identification of potent and selective triazolopyrimidine-based DHODH inhibitors with anti-malarial activity in vivo. Here we report x-ray structure determination of PfDHODH bound to three inhibitors from this series, representing the first of the enzyme bound to malaria specific inhibitors. We demonstrate that conformational flexibility results in an unexpected binding mode identifying a new hydrophobic pocket on the enzyme. Importantly this plasticity allows PfDHODH to bind inhibitors from different chemical classes and to accommodate inhibitor modifications during lead optimization, increasing the value of PfDHODH as a drug target. A second discovery, based on small molecule crystallography, is that the triazolopyrimidines populate a resonance form that promotes charge separation. These intrinsic dipoles allow formation of energetically favorable H-bond interactions with the enzyme. The importance of delocalization to binding affinity was supported by site-directed mutagenesis and the demonstration that triazolopyrimidine analogs that lack this intrinsic dipole are inactive. Finally, the PfDHODH-triazolopyrimidine bound structures provide considerable new insight into species-selective inhibitor binding in this enzyme family. Together, these studies will directly impact efforts to exploit PfDHODH for the development of anti-malarial chemotherapy.

| S-EPMC2785385 | biostudies-literature

A long-duration dihydroorotate dehydrogenase inhibitor (DSM265) for prevention and treatment of malaria.

Project description:Malaria is one of the most significant causes of childhood mortality, but disease control efforts are threatened by resistance of the Plasmodium parasite to current therapies. Continued progress in combating malaria requires development of new, easy to administer drug combinations with broad-ranging activity against all manifestations of the disease. DSM265, a triazolopyrimidine-based inhibitor of the pyrimidine biosynthetic enzyme dihydroorotate dehydrogenase (DHODH), is the first DHODH inhibitor to reach clinical development for treatment of malaria. We describe studies profiling the biological activity, pharmacological and pharmacokinetic properties, and safety of DSM265, which supported its advancement to human trials. DSM265 is highly selective toward DHODH of the malaria parasite Plasmodium, efficacious against both blood and liver stages of P. falciparum, and active against drug-resistant parasite isolates. Favorable pharmacokinetic properties of DSM265 are predicted to provide therapeutic concentrations for more than 8 days after a single oral dose in the range of 200 to 400 mg. DSM265 was well tolerated in repeat-dose and cardiovascular safety studies in mice and dogs, was not mutagenic, and was inactive against panels of human enzymes/receptors. The excellent safety profile, blood- and liver-stage activity, and predicted long half-life in humans position DSM265 as a new potential drug combination partner for either single-dose treatment or once-weekly chemoprevention. DSM265 has advantages over current treatment options that are dosed daily or are inactive against the parasite liver stage.

| S-EPMC4539048 | biostudies-literature

A novel series of human dihydroorotate dehydrogenase inhibitors discovered by in vitro screening: inhibition activity and crystallographic binding mode.

Project description:Human dihydroorotate dehydrogenase (DHODH), the enzyme that catalyzes the rate-limiting step in de novo pyrimidine biosynthesis, is considered to be an attractive target for potential treatment of autoimmune disease and cancer. Here, we present a novel class of human DHODH inhibitors with high inhibitory potency. The high-resolution crystal structures of human DHODH complexed with various agents reveal the details of their interactions. Comparisons with the binding modes of teriflunomide and brequinar provide insights that may facilitate the development of new inhibitors targeting human DHODH.

| S-EPMC6668370 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data