title: Phenotypic Screening In Vitro of Novel Aromatic Amidines against Trypanosoma cruzi.
abstract: The current treatment of Chagas disease (CD), based on nifurtimox and benznidazole (Bz), is unsatisfactory. In this context, we performed the phenotypic in vitro screening of novel mono- and diamidines and drug interaction assays with selected compounds. Ten novel amidines were tested for their activities against bloodstream trypomastigote (BT) and amastigote forms of Trypanosoma cruzi (Y and Tulahuen strains) and their toxicities for mammalian host cells (L929 cells and cardiac cells). Seven of 10 molecules were more active than Bz against BT, with the most active compound being the diamidine DB2267 (50% effective concentration [EC50] = 0.23 μM; selectivity index = 417), which was 28-fold more active and about 3 times more selective than the standard drug. Five of the six monoamidines were also more active than Bz. The combination of DB2267 and DB2236 in fixed-ratio proportions showed an additive effect (sum of fractional inhibitory concentrations < 4) on BT. Interestingly, when intracellular forms were exposed to DB2267, its activity was dependent on the parasite strain, being effective (EC50 = 0.87 ± 0.05 μM) against a discrete typing unit (DTU) II strain (strain Y) but not against a representative DTU VI strain (strain Tulahuen) even when different vehicles (β-cyclodextrin and dimethyl sulfoxide) were used. The intrinsic fluorescence of several diamidines allowed their uptake to be studied. Testing of the uptake of DB2236 (inactive) and DB2267 (active) by amastigotes of the Y strain showed that the two compounds were localized intracellularly in different compartments: DB2236 in the cytoplasm and DB2267 in the nucleus. Our present data encourage further studies regarding the activities of amidines and provide information which will help with the identification of novel agents for the treatment of CD.
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: Simões-Silva
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: A S G
authors.initials: AS
authors.lastname: Nefertiti
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: J S
authors.initials: JS
authors.lastname: De Araújo
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: M M
authors.initials: MM
authors.lastname: Batista
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: P B
authors.initials: PB
authors.lastname: Da Silva
authors.affiliation: Laboratório de Doenças Parasitárias, Escola de Medicina & Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
authors.forename: M T
authors.initials: MT
authors.lastname: Bahia
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: R S
authors.initials: RS
authors.lastname: Menna-Barreto
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: B P
authors.initials: BP
authors.lastname: Pavão
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia, USA.
authors.forename: J
authors.initials: J
authors.lastname: Green
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia, USA Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
authors.forename: A A
authors.initials: AA
authors.lastname: Farahat
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia, USA.
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Boykin
authors.affiliation: Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil soeiro@ioc.fiocruz.br.
authors.forename: M N C
authors.initials: MN
authors.lastname: Soeiro
mesh_terms: D000578:Amidines / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000469:parasitology; D014355:Chagas Disease / Q000188:drug therapy / Q000469:parasitology; D003593:Cytoplasm / Q000187:drug effects / Q000469:parasitology; D008322:Mammals / Q000469:parasitology; D021261:Parasitic Sensitivity Tests / Q000379:methods; D010641:Phenotype; D014344:Trypanocidal Agents / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000187:drug effects*
chemical_list: D000578:Amidines; D014344:Trypanocidal Agents