title: 2,4-Diaminopyrimidines as potent inhibitors of Trypanosoma brucei and identification of molecular targets by a chemical proteomics approach.
abstract: BACKGROUND
  There is an urgent need to develop new, safe and effective treatments for human African trypanosomiasis (HAT) because current drugs have extremely poor safety profiles and are difficult to administer. Here we report the discovery of 2,4-diaminopyrimidines, exemplified by 4-[4-amino-5-(2-methoxy-benzoyl)-pyrimidin-2-ylamino]-piperidine-1-carboxylic acid phenylamide (SCYX-5070), as potent inhibitors of Trypanosoma brucei and the related trypanosomatid protozoans Leishmania spp.
  
  
  RESULTS
  In this work we show that loss of T. brucei viability following SCYX-5070 exposure was dependent on compound concentration and incubation time. Pulse incubation of T. brucei with SCYX-5070 demonstrates that a short period of exposure (10-12 hrs) is required to produce irreversible effects on survival or commit the parasites to death. SCYX-5070 cured an acute trypanosomiasis infection in mice without exhibiting signs of compound related acute or chronic toxicity. To identify the molecular target(s) responsible for the mechanism of action of 2,4-diaminopyrimidines against trypanosomatid protozoa, a representative analogue was immobilized on a solid matrix (sepharose) and used to isolate target proteins from parasite extracts. Mitogen-activated protein kinases (MAPKs) and cdc2-related kinases (CRKs) were identified as the major proteins specifically bound to the immobilized compound, suggesting their participation in the pharmacological effects of 2,4-diaminopyrimidines against trypanosomatid protozoan parasites.
  
  
  CONCLUSIONS
  Results show that 2,4-diaminopyrimidines have a good in vitro and in vivo pharmacological profile against trypanosomatid protozoans and that MAPKs and CRKs are potential molecular targets of these compounds. The 2,4-diminipyrimidines may serve as suitable leads for the development of novel treatments for HAT.
authors.affiliation: SCYNEXIS Inc, Research Triangle Park, North Carolina, United States of America.
authors.forename: Luke
authors.initials: L
authors.lastname: Mercer
authors.forename: Tana
authors.initials: T
authors.lastname: Bowling
authors.forename: Joe
authors.initials: J
authors.lastname: Perales
authors.forename: Jennifer
authors.initials: J
authors.lastname: Freeman
authors.forename: Tien
authors.initials: T
authors.lastname: Nguyen
authors.forename: Cyrus
authors.initials: C
authors.lastname: Bacchi
authors.forename: Nigel
authors.initials: N
authors.lastname: Yarlett
authors.forename: Robert
authors.initials: R
authors.lastname: Don
authors.forename: Robert
authors.initials: R
authors.lastname: Jacobs
authors.forename: Bakela
authors.initials: B
authors.lastname: Nare
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D042846:CDC2-CDC28 Kinases / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D007891:Leishmania / Q000187:drug effects*; D051379:Mice; D050296:Microbial Viability / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011485:Protein Binding; D020543:Proteome / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D015800:Protozoan Proteins / Q000032:analysis*; D011743:Pyrimidines / Q000494:pharmacology*; D012376:Rodent Diseases / Q000188:drug therapy; D013997:Time Factors; D014346:Trypanosoma brucei brucei / Q000187:drug effects*; D014353:Trypanosomiasis, African / Q000188:drug therapy
chemical_list: D000981:Antiprotozoal Agents; D020543:Proteome; D015800:Protozoan Proteins; D011743:Pyrimidines; C017205:2,4-diaminopyrimidine; D042846:CDC2-CDC28 Kinases; D020928:Mitogen-Activated Protein Kinases