title: Diversity-oriented synthesis probe targets Plasmodium falciparum cytochrome b ubiquinone reduction site and synergizes with oxidation site inhibitors.
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.
authors.affiliation: Infectious Disease Initiative, The Broad Institute, Cambridge Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston.
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Lukens
authors.affiliation: Infectious Disease Initiative, The Broad Institute, Cambridge.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Heidebrecht
authors.affiliation: Therapeutics Platform.
authors.forename: Carol
authors.initials: C
authors.lastname: Mulrooney
authors.affiliation: Therapeutics Platform.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Beaudoin
authors.affiliation: Therapeutics Platform.
authors.forename: Eamon
authors.initials: E
authors.lastname: Comer
authors.affiliation: Therapeutics Platform.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Duvall
authors.affiliation: Therapeutics Platform.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Fitzgerald
authors.affiliation: Therapeutics Platform.
authors.forename: Daniela
authors.initials: D
authors.lastname: Masi
authors.affiliation: Genome Sequence and Analysis Program.
authors.forename: Kevin
authors.initials: K
authors.lastname: Galinsky
authors.affiliation: Therapeutics Platform.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Scherer
authors.affiliation: Therapeutics Platform.
authors.forename: Michelle
authors.initials: M
authors.lastname: Palmer
authors.affiliation: Therapeutics Platform.
authors.forename: Benito
authors.initials: B
authors.lastname: Munoz
authors.affiliation: Therapeutics Platform.
authors.forename: Michael
authors.initials: M
authors.lastname: Foley
authors.affiliation: Center for the Science of Therapeutics, The Broad Institute, Cambridge, Massachusetts.
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Schreiber
authors.affiliation: Infectious Disease Initiative, The Broad Institute, Cambridge.
authors.forename: Roger C
authors.initials: RC
authors.lastname: Wiegand
authors.affiliation: Infectious Disease Initiative, The Broad Institute, Cambridge Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston.
authors.forename: Dyann F
authors.initials: DF
authors.lastname: Wirth
mesh_terms: D000962:Antimalarials / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D001483:Base Sequence; D020134:Catalytic Domain; D045303:Cytochromes b / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D055808:Drug Discovery / Q000379:methods*; D004351:Drug Resistance; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D059014:High-Throughput Nucleotide Sequencing; D057166:High-Throughput Screening Assays; D006801:Humans; D047029:Lactams, Macrocyclic / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D016778:Malaria, Falciparum / Q000188:drug therapy* / Q000469:parasitology; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010671:Phenylurea Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D054852:Small Molecule Libraries; D014451:Ubiquinone / Q000378:metabolism; D000096926:Benzenesulfonamides
chemical_list: D000962:Antimalarials; D045303:Cytochromes b; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D010671:Phenylurea Compounds; D015800:Protozoan Proteins; D054852:Small Molecule Libraries; D014451:Ubiquinone; C000597962:ML238 compound; C000597963: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; D000096926:Benzenesulfonamides
keywords: cytochrome b; diversity-oriented synthesis; drug development; drug resistance; malaria; target identification