Diversity-oriented synthesis probe targets Plasmodium falciparum cytochrome b ubiquinone reduction site and synergizes with oxidation site inhibitors

J Infect Dis. 2015 Apr 1;211(7):1097-103. doi: 10.1093/infdis/jiu565. Epub 2014 Oct 21.

Abstract

Background: The emergence and spread of drug resistance to current antimalarial therapies remains a pressing concern, escalating the need for compounds that demonstrate novel modes of action. Diversity-Oriented Synthesis (DOS) libraries bridge the gap between conventional small molecule and natural product libraries, allowing the interrogation of more diverse chemical space in efforts to identify probes of novel parasite pathways.

Methods: We screened and optimized a probe from a DOS library using whole-cell phenotypic assays. Resistance selection and whole-genome sequencing approaches were employed to identify the cellular target of the compounds.

Results: We identified a novel macrocyclic inhibitor of Plasmodium falciparum with nanomolar potency and identified the reduction site of cytochrome b as its cellular target. Combination experiments with reduction and oxidation site inhibitors showed synergistic inhibition of the parasite.

Conclusions: The cytochrome b oxidation center is a validated antimalarial target. We show that the reduction site of cytochrome b is also a druggable target. Our results demonstrating a synergistic relationship between oxidation and reduction site inhibitors suggests a future strategy for new combination therapies in the treatment of malaria.

Keywords: cytochrome b; diversity-oriented synthesis; drug development; drug resistance; malaria; target identification.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antimalarials / chemical synthesis
  • Antimalarials / chemistry
  • Antimalarials / pharmacology*
  • Base Sequence
  • Catalytic Domain
  • Cytochromes b / antagonists & inhibitors*
  • Cytochromes b / chemistry
  • Cytochromes b / genetics
  • Drug Discovery / methods*
  • Drug Resistance
  • Drug Synergism
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology
  • High-Throughput Nucleotide Sequencing
  • High-Throughput Screening Assays
  • Humans
  • Lactams, Macrocyclic / chemical synthesis
  • Lactams, Macrocyclic / chemistry
  • Lactams, Macrocyclic / pharmacology
  • Malaria, Falciparum / drug therapy*
  • Malaria, Falciparum / parasitology
  • Molecular Sequence Data
  • Oxidation-Reduction
  • Phenylurea Compounds / chemical synthesis
  • Phenylurea Compounds / chemistry
  • Phenylurea Compounds / pharmacology
  • Plasmodium falciparum / drug effects*
  • Plasmodium falciparum / enzymology
  • Plasmodium falciparum / genetics
  • Protozoan Proteins / antagonists & inhibitors*
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics
  • Small Molecule Libraries
  • Ubiquinone / metabolism

Substances

  • Antimalarials
  • Enzyme Inhibitors
  • Lactams, Macrocyclic
  • ML238 compound
  • N-((11-(1-(dimethylamino)propan-2-yl)-14-(3-(3,5-dimethylisoxazol-4-yl)ureido)-2,9-dimethyl-12-oxo-2,3,4,5,6,8,9,10,11,12-decahydrobenzo(b)(1,9,5)dioxaazacyclotetradecin-8-yl)methyl)-4-fluoro-N-methylbenzenesulfonamide
  • Phenylurea Compounds
  • Protozoan Proteins
  • Small Molecule Libraries
  • Ubiquinone
  • Cytochromes b

Associated data

  • GENBANK/KM032225
  • GENBANK/KM032226
  • GENBANK/KM032227
  • GENBANK/KM032228
  • GENBANK/KM032229
  • GENBANK/KM032230
  • GENBANK/KM032231
  • GENBANK/KM032232
  • GENBANK/KM032233
  • GENBANK/KM032234
  • GENBANK/KM032235
  • GENBANK/KM032236
  • GENBANK/KM032237
  • GENBANK/KM032238
  • GENBANK/KM032239
  • GENBANK/KM032240
  • GENBANK/KM032241
  • GENBANK/KM032242
  • GENBANK/KM032243
  • GENBANK/KM032244
  • GENBANK/KM032245
  • GENBANK/KM032246
  • GENBANK/KM032247
  • SRA/SRX120899