Trypanocidal effect of isotretinoin through the inhibition of polyamine and amino acid transporters in Trypanosoma cruzi

REIGADA C; SAYÉ M; AVILA CC; PEREIRA CA; VALERA VERA EA; MIRANDA MR

La Plata

Workshop; International workshop on drug design and neglected tropical diseases; 2016

Purpose: Polyamines are essential compounds in all living organisms and in the specific case of Trypanosoma cruzi they are exclusively obtained through transport processes. Previous works reported that retinol acetate inhibits Leishmania growth and decreases its intracellular polyamine concentration. The present work describes a combined strategy of drug repositioning by virtual screening followed by in vitro assays to find drugs able to inhibit TcPAT12, the only polyamine transporter described in T. cruzi.Methodology: A ligand-based virtual screening by similarity was performed on the database of approved drugs and nutraceuticals of FDA, using Tanimoto coefficient and Retinol acetate as reference molecule, 7 withdrawn compounds where used in molecular docking assays against an homology model of polyamine transporter TcPAT12, taking as flexible residues Asn245, Tyr148 and Tyr400. One of the tested molecules, the isotretinoin, was selected for in-vitro tests of trypanocidal activity, evaluating growth of T. cruzi (Y-strain) epimastigotes and burst of trypomastigotes from infected CHO-K1 cells at different concentrations of the drug.Results: Seven retinoids used in medicine were obtained by similarity screening of 3,000 FDA approved drugs. Then, according to the molecular docking assays between TcPAT12 and the selected retinoids, isotretinoin was selected for further in vitro studies. Isotretionoin inhibited the polyamine transport, and also all tested amino acid transporters from the same protein family (TcAAAP), with calculated IC50 values in the range of 4.6 - 10.3 μM. Isotretinoin also showed a strong trypanocidal effect on trypomastigotes with calculated IC50 of 130 nM, being significantly less effective over the epimastigote stage (IC50 = 30.6 μM).Conclusion: Results suggest that isotretinoin is a promising trypanocidal drug, for being a multitarget inhibitor of essential transporters. In addition, it is an already approved drug for human use, which significantly reduces the requirements for its possible application against Chagas disease.