T. brucei whole cell proteome changes upon exposure to the experimental phthalimide-based trypanocidal drug PHT-39

In a phenotypic screening approach of novel molecules composed of a synergistic combination of phthalimide, benzimidazole, and triazole scaffolds we discovered compounds with potent anti-leishmanial activity. The resulting early-lead compound PHT-39, which contains a trifluoromethyl substitution, demonstrated the highest efficacy in a Leishmania infantum intramacrophage assay, with an EC50 of 1.2 +/- 3.2 μM.Cytotoxicity testing of PHT-39 in Hep-G2 cells indicated high selectivity of over 90-fold. To investigate the mechanism of action we carried out experiments in Trypanosoma brucei, which is also sensitive to PHT-39. Here we used liquid chromatography coupled with tandem mass spectrometry (LC-MSMS) to quantify the effects of PH-39 exposure on the global protein landscape in T. brucei.