congresos y reuniones científicas
Different roads to search for novel trypanocidal strategies
L. FRACCAROLI,; MD, RUIZ; DE PINO, V; TORRES, PS; BALCAZAR, D; L. LAROCCA; VANRELL. C; P. ROMANO; CARRILLO C
Congreso; XXXI Molecular Parasitology Meeting; 2020
Chagas disease is an endemic parasitosis originally from Latin America, caused by the protozoan Trypanosoma cruzi (T. cruzi). As current therapies (benznidazole and nifurtimox) are limited in efficacy and show multiple side effects, there is a need to identify new effective and specific therapeutic strategies.In this sense, there are several ways to find potential trypanocidal compounds; the present work focuses on two strategies: 1- the target repurposing and 2- the use of literature and traditional medicine to find new uses to approved drugs or natural compounds. The strategy 1 compares T. cruzi targets with those that are homologues in other organisms (which are characterized and their interaction with drugs is known). In line with this, we study anthraciclines (DXR-doxorrubicin and DNR-daunorrubicin) for being drugs used in humans and incorporated to cells by the hOCT1 transporter (a low affinity polyamine transporter) and potentially affecting T. cruzi polyamine transporter TcPAT12. Our results showed that DXR and DNR affected T. cruzi epimastigotes survival and proliferation (EC50 0.1uM for DNR and 2uM for DXR), metacyclogenesis (from 14.8% in control condition to 8.9% with DNR) and replicative capacity of amastigotes (reduced by half in the presence of DNR). These effects could be related both to the decrease of polyamine uptake and intracellular concentration by anthracyclines, and to their cellular toxic effects.The strategy 2 focussed on the antiparasitic effect of certain drugs or natural compounds reported by literature. One of our ongoing studies is the Melia azedarach (MA) extract, obtained from ripe fruits of the tree, which presents antifungal and antihelmintic properties. The extracts were obtained by different extraction methods using aqueous and organic solvents. Those extracts obtained with DMSO or ethanol showed an antiproliferative effect on T. cruzi epimastigotes with EC50 values lower than 1 mg/ml. The extracts maintained their activity when conserved at -20°C while at 4°C it diminished by half. Preliminary HPLC analysis showed that individual fractions of the MA extract did not have an effect in the epimastigotes proliferation, indicating the presence of several bioactive compounds which interact in order to be cytotoxic. Further studies are required to identify and characterize those compounds in the MA extract. The results shown in this work intend to illustrate some of the approaches used by our research group in order to find and characterize potential trypanocidal drugs. Our analysis strategy starts with the screening of the drugs or extracts in T. cruzi epimastigotes cultures and then continues in other stages of the life cycle to assess the infectivity and intracellular replication. Further studies in acute and chronic Chagas disease animal models are required to have a global understanding of how a drug can be postulated as a good candidate to use in the clinic.