Genome-wide mutagenesis and multi-drug resistance in American trypanosomes induced by the front-line drug benznidazole

• Published in: Scientific reports 2017-10, Vol.7 (1), p.14407-8, Article 14407
• Main Authors: Campos, Mônica C., Phelan, Jody, Francisco, Amanda F., Taylor, Martin C., Lewis, Michael D., Pain, Arnab, Clark, Taane G., Kelly, John M.
• Format: Article
• Language: English
• Subjects: 45; 45/23; 59; 59/5; 631/326/417/1716; 631/326/417/2551; 64; 64/60; Animals; Benznidazole; Biosynthesis; Chagas disease; Chagas Disease - drug therapy; Cloning; Cross-resistance; Deoxyribonucleic acid; Disease Models, Animal; DNA; DNA repair; Drug resistance; Drug Resistance, Multiple; Ergosterol; Female; Genome, Protozoan - drug effects; Genomes; Humanities and Social Sciences; Metabolites; Mice, SCID; Mitochondria; multidisciplinary; Multidrug resistance; Mutagenesis; Mutagenesis - drug effects; Mutagens - metabolism; Mutagens - pharmacology; Mutation; Nitroimidazoles - metabolism; Nitroimidazoles - pharmacology; Nitroreductase; Parasite resistance; Parasites; Posaconazole; Protozoa; Science; Science (multidisciplinary); Sequence Analysis, DNA; Triazoles - pharmacology; Trypanocidal Agents - metabolism; Trypanocidal Agents - pharmacology; Trypanosoma cruzi; Trypanosoma cruzi - drug effects; Trypanosoma cruzi - genetics; Trypanosoma cruzi - pathogenicity; Vector-borne diseases; Vigilance
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-14986-6

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects 5–8 million people in Latin America. Although the nitroheterocyclic compound benznidazole has been the front-line drug for several decades, treatment failures are common. Benznidazole is a pro-drug and is bio-activated within the parasite by the mitochondrial nitroreductase TcNTR-1, leading to the generation of reactive metabolites that have trypanocidal activity. To better assess drug action and resistance, we sequenced the genomes of T. cruzi Y strain (35.5 Mb) and three benznidazole-resistant clones derived from a single drug-selected population. This revealed the genome-wide accumulation of mutations in the resistant parasites, in addition to variations in DNA copy-number. We observed mutations in DNA repair genes, linked with increased susceptibility to DNA alkylating and inter-strand cross-linking agents. Stop-codon-generating mutations in TcNTR-1 were associated with cross-resistance to other nitroheterocyclic drugs. Unexpectedly, the clones were also highly resistant to the ergosterol biosynthesis inhibitor posaconazole, a drug proposed for use against T. cruzi infections, in combination with benznidazole. Our findings therefore identify the highly mutagenic activity of benznidazole metabolites in T. cruzi , demonstrate that this can result in multi-drug resistance, and indicate that vigilance will be required if benznidazole is used in combination therapy.