Different roads to search for novel trypanocidal strategies

FRACCAROLI LAURA; RUIZ DANIELA; DE PINO, VERÓNICA; TORRES PABLO; BALCAZAR DARIO; LAROCCA LUCIANA; VANRELL CRISTINA; ROMANO PATRICIA; CAROLINA CARRILLO

Congreso; Molecular Parasitology Meeting XXXI. Anywhere and Everywhere; 2020

Chagas disease isan endemic parasitosis originally from Latin America, caused by the protozoan Trypanosoma cruzi (T. cruzi). As current therapies (benznidazole and nifurtimox) arelimited in efficacy and show multiple side effects, there is a need to identifynew effective and specific therapeutic strategies. In this sense,there are several ways to find potential trypanocidal compounds; the presentwork focuses on two strategies: 1- the target repurposing and 2- the use ofliterature and traditional medicine to find new uses to approved drugs ornatural compounds. The strategy 1compares T. cruzi targets with thosethat are homologues in other organisms (which are characterized and theirinteraction with drugs is known). In line with this, we study anthraciclines(DXR-doxorrubicin and DNR-daunorrubicin) for being drugs used in humans andincorporated to cells by the hOCT1 transporter (a low affinity polyaminetransporter) and potentially affecting T.cruzi polyamine transporter TcPAT12. Our results showed that DXR and DNRaffected T. cruzi epimastigotessurvival and proliferation (EC50 0.1uM for DNR and 2uM for DXR),metacyclogenesis (from 14.8% in control condition to 8.9% with DNR) andreplicative capacity of amastigotes (reduced by half in the presence of DNR).These effects could be related both to the decrease of polyamine uptake andintracellular concentration by anthracyclines, and to their cellular toxiceffects. The strategy 2focussed on the antiparasitic effect of certain drugs or natural compoundsreported by literature. One of our ongoing studies is the Melia azedarach (MA) extract, obtained from ripe fruits of thetree, which presents antifungal and antihelmintic properties. The extracts wereobtained by different extraction methods using aqueous and organic solvents.Those extracts obtained with DMSO or ethanol showed an antiproliferative effecton T. cruzi epimastigotes with EC50values lower than 1 mg/ml. The extracts maintained their activity whenconserved at -20°C while at 4°C it diminished by half. Preliminary HPLCanalysis showed that individual fractions of the MA extract did not have aneffect in the epimastigotes proliferation, indicating the presence of severalbioactive compounds which interact in order to be cytotoxic. Further studiesare required to identify and characterize those compounds in the MA extract. The results shownin this work intend to illustrate some of the approaches used by our researchgroup in order to find and characterize potential trypanocidal drugs. Ouranalysis strategy starts with the screening of the drugs or extracts in T. cruzi epimastigotes cultures and thencontinues in other stages of the life cycle to assess the infectivity andintracellular replication. Further studies in acute and chronic Chagas diseaseanimal models are required to have a global understanding of how a drug can bepostulated as a good candidate to use in the clinic.