title: An Aromatic Diamidine That Targets Kinetoplast DNA, Impairs the Cell Cycle in Trypanosoma cruzi, and Diminishes Trypomastigote Release from Infected Mammalian Host Cells.
abstract: Trypanosoma cruzi is the etiological agent of Chagas disease, affecting approximately 10 million people in the Americas and with some 40 million people at risk. The objective of this study was to evaluate the anti-T. cruzi activity of three new diamidines that have a 3,4-ethylenedioxy extension of the thiophene core, designated MB17, MB19, and MB38. All three diamidines exhibited dose-dependent inhibition of epimastigote replication. The mechanisms of action of these diamidines were investigated. Unlike MB17 and MB19, MB38 exhibited a significant increase in the number of annexin-propidium iodide double-labeled cells compared to levels in control parasites. As MB17 had shown a lower 50% inhibitory concentration (IC50) against epimastigote growth, the mechanism of action of this drug was studied in more detail. MB17 triggered a decrease in the intracellular ATP levels. As a consequence, MB17 affected the genomic DNA and kinetoplast DNA (kDNA) and impaired the parasite cell cycle. Moreover, MB17 caused DNA fragmentation, with a more severe effect on kDNA than on nuclear DNA, resulting in dyskinetoplastic cells. MB17 was tested for toxicity and effectiveness for the treatment of infected CHO-K1 cells, exhibiting a 50% cytotoxic concentration (CC50) of 13.47 ± 0.37 μM and an IC50 of 0.14 ± 0.12 μM against trypomastigote release. MB17 also diminished the infection index by 60% at 0.5 μM. In conclusion, despite belonging to the same family, these diamidines have different efficiencies. To summarize, MB17 was the most potent of these diamidines against epimastigotes, producing DNA damage preferentially in kDNA, impairing the parasite cell cycle, and decreasing the infection index and trypomastigote release from infected mammalian host cells, with a high selectivity index (SI) (<90). These data suggest that MB17 could be an interesting lead compound against T. cruzi.
authors.affiliation: Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Richard M B M
authors.initials: RM
authors.lastname: Girard
authors.affiliation: Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Marcell
authors.initials: M
authors.lastname: Crispim
authors.affiliation: Department of Chemistry and Biochemistry, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Stolić
authors.affiliation: Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Flávia Silva
authors.initials: FS
authors.lastname: Damasceno
authors.affiliation: Special Laboratory of Cell Cycle, Butantan Institute, São Paulo, SP, Brazil Center of Toxins, Immune Response and Cell Signaling, Butantan Institute, São Paulo, SP, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Santos da Silva
authors.affiliation: Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Eizabeth Mieko Furusho
authors.initials: EM
authors.lastname: Pral
authors.affiliation: Special Laboratory of Cell Cycle, Butantan Institute, São Paulo, SP, Brazil Center of Toxins, Immune Response and Cell Signaling, Butantan Institute, São Paulo, SP, Brazil.
authors.forename: Maria Carolina
authors.initials: MC
authors.lastname: Elias
authors.affiliation: Department of Chemistry and Biochemistry, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Bajić
authors.affiliation: Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil asilber@usp.br.
authors.forename: Ariel Mariano
authors.initials: AM
authors.lastname: Silber
mesh_terms: D000818:Animals; D001550:Benzamidines / Q000737:chemistry / Q000494:pharmacology; D016466:CHO Cells / Q000469:parasitology; D002453:Cell Cycle / Q000187:drug effects; D003412:Cricetulus; D018105:DNA, Kinetoplast; D015394:Molecular Structure; D010419:Pentamidine / Q000737:chemistry / Q000494:pharmacology; D013876:Thiophenes / Q000737:chemistry / Q000494:pharmacology; D014344:Trypanocidal Agents / Q000737:chemistry / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000166:cytology / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development
chemical_list: C000621310:2,5-bis(4-amidinophenyl)-3,4-ethylenedioxythiophene; D001550:Benzamidines; D018105:DNA, Kinetoplast; D013876:Thiophenes; D014344:Trypanocidal Agents; D010419:Pentamidine