Drug Repurposing in Chagas Disease: Chloroquine Potentiates Benznidazole Activity against Trypanosoma cruzi In Vitro and In Vivo.

Drug combinations and drug repurposing have emerged as promising strategies to develop novel treatments for infectious diseases, including Chagas disease. In this study, we aimed to investigate whether the repurposed drugs chloroquine (CQ) and colchicine (COL), known to inhibit Trypanosoma cruzi infection in host cells, could boost the anti-T. cruzi effect of the trypanocidal drug benznidazole (BZN), increasing its therapeutic efficacy while reducing the dose needed to eradicate the parasite. The combination of BZN and COL exhibited cytotoxicity to infected cells and low antiparasitic activity. Conversely, a combination of BZN and CQ significantly reduced T. cruzi infection in vitro, with no apparent cytotoxicity. This effect seemed to be consistent across different cell lines and against both the partially BZN-resistant Y and the highly BZN-resistant Colombiana strains. In vivo experiments in an acute murine model showed that the BZN+CQ combination was eight times more effective in reducing T. cruzi infection in the acute phase than BZN monotherapy. In summary, our results demonstrate that the concomitant administration of CQ and BZN potentiates the trypanocidal activity of BZN, leading to a reduction in the dose needed to achieve an effective response. In a translational context, it could represent a higher efficacy of treatment while also mitigating the adverse effects of high doses of BZN. Our study also reinforces the relevance of drug combination and repurposing approaches in the field of Chagas disease drug discovery.

Investigating the structure-activity relationships of N'-[(5-nitrofuran-2-yl) methylene] substituted hydrazides against Trypanosoma cruzi to design novel active compounds.

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected chronic tropical infection endemic in Latin America. New and effective treatments are urgently needed because the two available drugs - benznidazole (BZD) and nifurtimox (NFX) - have limited curative power in the chronic phase of the disease. We have previously reported the design and synthesis of N'-[(5-nitrofuran-2-yl) methylene] substituted hydrazides that showed high trypanocidal activity against axenic epimastigote forms of three T. cruzi strains. Here we show that these compounds are also active against a BZD- and NFX-resistant strain. Herein, multivariate approaches (hierarchical cluster analysis and principal component analysis) were applied to a set of thirty-six formerly characterized compounds. Based on the findings from exploratory data analysis, novel compounds were designed and synthesized. These compounds showed two-to three-fold higher trypanocidal activity against epimastigote forms than the previous set and were 25-30-fold more active than BZD. Their activity was also evaluated against intracellular amastigotes by high content screening (HCS). The most active compounds (BSF-38 to BSF-40) showed a selective index (SI') greater than 200, in contrast to the SI' values of reference drugs (NFX, 16.45; BZD, > 3), and a 70-fold greater activity than BZD. These findings indicate that nitrofuran compounds designed based on the activity against epimastigote forms show promising trypanocidal activity against intracellular amastigotes, which correspond to the predominant parasite stage in the chronic phase of Chagas disease.

Investigating the structure-activity relationships of N '-[(5-nitrofuran-2-yl) methylene] substituted hydrazides against Trypanosoma cruzi to design novel active compounds

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected chronic tropical infection endemic in Latin America. New and effective treatments are urgently needed because the two available drugs - benznidazole (BZD) and nifurtimox (NFX) - have limited curative power in the chronic phase of the disease. We have previously reported the design and synthesis of N'-[(5-nitrofuran-2-yl) methylene] substituted hydrazides that showed high trypanocidal activity against axenic epimastigote forms of three T cruzi strains. Here we show that these compounds are also active against a BZD- and NFX-resistant strain. Herein, multivariate approaches (hierarchical cluster analysis and principal component analysis) were applied to a set of thirty-six formerly characterized compounds. Based on the findings from exploratory data analysis, novel compounds were designed and synthesized. These compounds showed two-to three-fold higher trypanocidal activity against epimastigote forms than the previous set and were 25-30-fold more active than BZD. Their activity was also evaluated against intracellular amastigotes by high content screening (HCS). The most active compounds (BSF-38 to BSF-40) showed a selective index (SI') greater than 200, in contrast to the SI' values of reference drugs (NFX, 16.45; BZD, > 3), and a 70-fold greater activity than BZD. These findings indicate that nitrofuran compounds designed based on the activity against epimastigote forms show promising trypanocidal activity against intracellular amastigotes, which correspond to the predominant parasite stage in the chronic phase of Chagas disease.

Investigating the structure-activity relationships of N '-[(5-nitrofuran-2-yl) methylene] substituted hydrazides against Trypanosoma cruzi to design novel active compounds

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected chronic tropical infection endemic in Latin America. New and effective treatments are urgently needed because the two available drugs - benznidazole (BZD) and nifurtimox (NFX) - have limited curative power in the chronic phase of the disease. We have previously reported the design and synthesis of N'-[(5-nitrofuran-2-yl) methylene] substituted hydrazides that showed high trypanocidal activity against axenic epimastigote forms of three T cruzi strains. Here we show that these compounds are also active against a BZD- and NFX-resistant strain. Herein, multivariate approaches (hierarchical cluster analysis and principal component analysis) were applied to a set of thirty-six formerly characterized compounds. Based on the findings from exploratory data analysis, novel compounds were designed and synthesized. These compounds showed two-to three-fold higher trypanocidal activity against epimastigote forms than the previous set and were 25-30-fold more active than BZD. Their activity was also evaluated against intracellular amastigotes by high content screening (HCS). The most active compounds (BSF-38 to BSF-40) showed a selective index (SI') greater than 200, in contrast to the SI' values of reference drugs (NFX, 16.45; BZD, > 3), and a 70-fold greater activity than BZD. These findings indicate that nitrofuran compounds designed based on the activity against epimastigote forms show promising trypanocidal activity against intracellular amastigotes, which correspond to the predominant parasite stage in the chronic phase of Chagas disease.

A novel ABCG-like transporter of Trypanosoma cruzi is involved in natural resistance to benznidazole.

Benznidazole (BZ) is one of the two drugs used for Chagas disease treatment. Nevertheless therapeutic failures of BZ have been reported, which were mostly attributed to variable drug susceptibility among Trypanosoma cruzi strains. ATP-binding cassette (ABC) transporters are involved in a variety of translocation processes and some members have been implicated in drug resistance. Here we report the characterisation of the first T. cruzi ABCG transporter gene, named TcABCG1, which is over-expressed in parasite strains naturally resistant to BZ. Comparison of TcABCG1 gene sequence of two TcI BZ-resistant strains with CL Brener BZ-susceptible strain showed several single nucleotide polymorphisms, which determined 11 amino acid changes. CL Brener transfected with TcI transporter genes showed 40-47% increased resistance to BZ, whereas no statistical significant increment in drug resistance was observed when CL Brener was transfected with the homologous gene. Only in the parasites transfected with TcI genes there was 2-2.6-fold increased abundance of TcABCG1 transporter protein. The analysis in wild type strains also suggests that the level of TcABCG1 transporter is related to BZ natural resistance. The characteristics of untranslated regions of TcABCG1 genes of BZ-susceptible and resistant strains were investigated by computational tools.

A novel ABCG-like transporter of Trypanosoma cruzi is involved in natural resistance to benznidazole

Benznidazole (BZ) is one of the two drugs used for Chagas disease treatment. Nevertheless therapeutic failures of BZ have been reported, which were mostly attributed to variable drug susceptibility among Trypanosoma cruzi strains. ATP-binding cassette (ABC) transporters are involved in a variety of translocation processes and some members have been implicated in drug resistance. Here we report the characterisation of the first T. cruzi ABCG transporter gene, named TcABCG1, which is over-expressed in parasite strains naturally resistant to BZ. Comparison of TcABCG1 gene sequence of two TcI BZ-resistant strains with CL Brener BZ-susceptible strain showed several single nucleotide polymorphisms, which determined 11 amino acid changes. CL Brener transfected with TcI transporter genes showed 40-47% increased resistance to BZ, whereas no statistical significant increment in drug resistance was observed when CL Brener was transfected with the homologous gene. Only in the parasites transfected with TcI genes there was 2-2.6-fold increased abundance of TcABCG1 transporter protein. The analysis in wild type strains also suggests that the level of TcABCG1 transporter is related to BZ natural resistance. The characteristics of untranslated regions of TcABCG1 genes of BZ-susceptible and resistant strains were investigated by computational tools.

Designing and exploring active N'-[(5-nitrofuran-2-yl) methylene] substituted hydrazides against three Trypanosoma cruzi strains more prevalent in Chagas disease patients.

Chagas disease affects around 8 million people worldwide and its treatment depends on only two nitroheterocyclic drugs, benznidazole (BZD) and nifurtimox (NFX). Both drugs have limited curative power in chronic phase of disease. Nifuroxazide (NF), a nitroheterocyclic drug, was used as lead to design a set of twenty one compounds in order to improve the anti-Trypanosoma cruzi activity. Lipinski's rules were considered in order to support drug-likeness designing. The set of N'-[(5-nitrofuran-2-yl) methylene] substituted hydrazides was assayed against three T. cruzi strains, which represent the discrete typing units more prevalent in human patients: Y (TcII), Silvio X10 cl1 (TcI), and Bug 2149 cl10 (TcV). All the derivatives, except one, showed enhanced trypanocidal activity against the three strains as compared to BZD. In the Y strain 62% of the compounds were more active than NFX. The most active compound was N'-((5-nitrofuran-2-yl) methylene)biphenyl-4-carbohydrazide (C20), which showed IC50 values of 1.17 ± 0.12 µM; 3.17 ± 0.32 µM; and 1.81 ± 0.18 µM for Y, Silvio X10 cl1, and Bug 2149 cl10 strains, respectively. Cytotoxicity assays with human fibroblast cells have demonstrated high selectivity indices for several compounds. Exploratory data analysis indicated that primarily topological, steric/geometric, and electronic properties have contributed to the discrimination of the set of investigated compounds. The findings can be helpful to drive the designing, and subsequently, the synthesis of additional promising drugs against Chagas disease.