title: Genomic and Proteomic Studies on the Mode of Action of Oxaboroles against the African Trypanosome.
abstract: SCYX-7158, an oxaborole, is currently in Phase I clinical trials for the treatment of human African trypanosomiasis. Here we investigate possible modes of action against Trypanosoma brucei using orthogonal chemo-proteomic and genomic approaches. SILAC-based proteomic studies using an oxaborole analogue immobilised onto a resin was used either in competition with a soluble oxaborole or an immobilised inactive control to identify thirteen proteins common to both strategies. Cell-cycle analysis of cells incubated with sub-lethal concentrations of an oxaborole identified a subtle but significant accumulation of G2 and >G2 cells. Given the possibility of compromised DNA fidelity, we investigated long-term exposure of T. brucei to oxaboroles by generating resistant cell lines in vitro. Resistance proved more difficult to generate than for drugs currently used in the field, and in one of our three cell lines was unstable. Whole-genome sequencing of the resistant cell lines revealed single nucleotide polymorphisms in 66 genes and several large-scale genomic aberrations. The absence of a simple consistent mechanism among resistant cell lines and the diverse list of binding partners from the proteomic studies suggest a degree of polypharmacology that should reduce the risk of resistance to this compound class emerging in the field. The combined genetic and chemical biology approaches have provided lists of candidates to be investigated for more detailed information on the mode of action of this promising new drug class.
authors.affiliation: School of Life Sciences, University of Dundee, Dundee, United Kingdom.
authors.forename: Deuan C
authors.initials: DC
authors.lastname: Jones
authors.affiliation: Parasite Genomics, Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom.
authors.forename: Bernardo J
authors.initials: BJ
authors.lastname: Foth
authors.affiliation: Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Urbaniak
authors.affiliation: School of Life Sciences, University of Dundee, Dundee, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Patterson
authors.affiliation: School of Life Sciences, University of Dundee, Dundee, United Kingdom.
authors.forename: Han B
authors.initials: HB
authors.lastname: Ong
authors.affiliation: Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Berriman
authors.affiliation: School of Life Sciences, University of Dundee, Dundee, United Kingdom.
authors.forename: Alan H
authors.initials: AH
authors.lastname: Fairlamb
mesh_terms: D000981:Antiprotozoal Agents / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology*; D001896:Boron Compounds / Q000494:pharmacology*; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004351:Drug Resistance; D020869:Gene Expression Profiling; D018503:Genome, Protozoan; D023281:Genomics; D011110:Polymorphism, Genetic; D020543:Proteome / Q000032:analysis*; D040901:Proteomics; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D014346:Trypanosoma brucei brucei / Q000187:drug effects*
chemical_list: D000981:Antiprotozoal Agents; D001549:Benzamides; D001896:Boron Compounds; D016054:DNA, Protozoan; D020543:Proteome; C557508:SCYX 7158