Untargeted Metabolomics Reveals a Lack Of Synergy between Nifurtimox and Eflornithine against Trypanosoma brucei

Abstract

A non-targeted metabolomics-based approach is presented that enables the study of pathways in response to drug action with the aim of defining the mode of action of trypanocides. Eflornithine, a polyamine pathway inhibitor, and nifurtimox, whose mode of action involves its metabolic activation, are currently used in combination as first line treatment against stage 2, CNS-involved, human African trypanosomiasis (HAT). Drug action was assessed using an LC-MS based non-targeted metabolomics approach. Eflornithine revealed the expected changes to the polyamine pathway as well as several unexpected changes that point to pathways and metabolites not previously described in bloodstream form trypanosomes, including a lack of arginase activity and N-acetylated ornithine and putrescine. Nifurtimox was shown to be converted to a trinitrile metabolite indicative of metabolic activation, as well as inducing changes in levels of metabolites involved in carbohydrate and nucleotide metabolism. However, eflornithine and nifurtimox failed to synergise anti-trypanosomal activity in vitro, and the metabolomic changes associated with the combination are the sum of those found in each monotherapy with no indication of additional effects. The study reveals how untargeted metabolomics can yield rapid information on drug targets that could be adapted to any pharmacological situation.

Potent Trypanocidal Curcumin Analogs Bearing a Monoenone Linker Motif Act on Trypanosoma brucei by Forming an Adduct with Trypanothione

“…This contrasts with treatment of the same trypanosome strain with the inhibitor of ornithyl decarboxylase eflornithine, which resulted in rapid changes in intracellular levels of putrescine, ornithine (and both of their acetylated forms), and 59-thioadenosine metabolites (Vincent et al, 2012).…”

Metabolomic-Based Strategies for Anti-Parasite Drug Discovery

“…2 The results highlighted the fact that in vitro eflornithine and nifurtimox are antagonistic, as shown in both the IC 50 values in combination by isobologram analysis and each drug's effects on the metabolome. 2 The MOA of nifurtimox was also analyzed, and although the primary target of the drug was not discovered, increases in nucleotides and nucleobases were detected, suggesting a degradation of DNA and RNA 2 (Fig. 2).…”

Metabolomics: A Tool Ahead for Understanding Molecular Mechanisms of Drugs and Diseases

“…A review of metabolomics of anti-protozoals [19] done on parasite metabolome threw light on some newly discovered facts like the inhibition of ornithine decarboxylase by eflornithine, a drug used against trypanosomiasis. It was seen that the substrate, ornithine accumulates while depletion of products like putrescine and spermidine occurs [20]. In case of nifurtimox, metabolomics identified perturbations in parasitic nucleotide and glycolytic pathways [20].…”

“…It was seen that the substrate, ornithine accumulates while depletion of products like putrescine and spermidine occurs [20]. In case of nifurtimox, metabolomics identified perturbations in parasitic nucleotide and glycolytic pathways [20]. Likewise for the anti-leishmaniasis drugs, amphotericin B and miltefosine, interaction with the sterol and phospholipid metabolism was found respectively [19].…”