In Silico, In Vitro, and Pharmacokinetic Studies of UBMC-4, a Potential Novel Compound for Treating against Trypanosoma cruzi

Abstract

The lack of therapeutic alternatives for the treatment of Chagas disease, a neglected disease, drives the discovery of new drugs with trypanocidal activity. Consequently, we conducted in vitro studies using UBMC-4, a potential Trypanosoma cruzi AKT-like pleckstrin homology (PH) domain inhibitory compound found using bioinformatics tools. The half effective concentration (EC50) on intracellular amastigotes was determined at 1.85 ± 1 μM showing low cytotoxicity (LC50) > 40 μM on human cell lines tested. In order to study the lethal effect caused by the compound on epimastigotes, morphological changes were assessed by scanning and transmission electron microscopy. Progressive alterations such as flagellum inactivation, cell size reduction, nuclear structure alteration, condensation of chromatin towards the nuclear periphery, vacuole formation, and mitochondrial swelling with kinetoplast integrity loss were evidenced. In addition, apoptosis-like markers in T. cruzi were assessed by flow cytometry, demonstrating that the effect of UBMC-4 on T. cruzi AKT-like kinase reduced the tolerance to nutritional stress-triggered, apoptosis-like events, including DNA fragmentation, mitochondrial damage, and loss of plasma membrane integrity. After this, UBMC-4 was formulated for oral administration and pharmacokinetics were analyzed in a mouse model. Finally, upon oral administration of 200 mg/kg in mice, we found that a UBMC-4 plasma concentration remaining in circulation beyond 24 h after administration is well described by the two-compartment model. We conclude that UBMC-4 has an effective trypanocidal activity in vitro at low concentrations and this effect is evident in T. cruzi cell structures. In mice, UBMC-4 was well absorbed and reached plasma concentrations higher than the EC50, showing features that would aid in developing a new drug to treat Chagas disease.

Structural investigation of Trypanosoma cruzi Akt-like kinase as drug target against Chagas disease

“…Akt kinases play a central role in all organisms as they are key regulators involved in the balance between growth, proliferation and apoptosis 25 , 26 . Tc Akt inhibition causes apoptosis-like events in T. cruzi , confirming its essential role for the survival of the parasite 23 , 24 , 27 . Furthermore, Tc Akt is present in all stages of the parasite life cycle—epimastigotes, trypomastigotes and amastigotes—which is crucial for effective treatment of CD.…”

“…To date, two Tc Akt inhibitors UBMC-4 23 and UBMC-6 24 have been defined, both detected via virtual screening and molecular docking approaches. Nevertheless, the lack of structural information restricts a detailed understanding of the inhibitory mechanisms.…”

“…Tc Akt was previously proposed as a promising target for the development of drugs against CD 23 , 24 . Akt kinases play a central role in all organisms as they are key regulators involved in the balance between growth, proliferation and apoptosis 25 , 26 .…”

“…Furthermore, Tc Akt is present in all stages of the parasite life cycle—epimastigotes, trypomastigotes and amastigotes—which is crucial for effective treatment of CD. Considerable effort has been made to inhibit Tc Akt based on bioinformatics and molecular docking studies 23 , 24 . However, the three-dimensional structure of the Akt- like kinase in trypanosomatids has not been determined yet, resulting in a lack of detailed information and understanding of its mechanism of action 27 .…”

“…Further docking experiments show that human Akt inhibitors PIT-1 32 , 54 and capivasertib 55 , 56 recognize Tc Akt via similar binding modes compared to Hs Akt. Additionally, based on the AF structure of Tc Akt, the exact localization of the binding site of previously described Tc Akt inhibitors UBMC-4 23 and UBMC-6 24 could be determined at the kinase domain of Tc Akt, thus suggesting kinase-involved inhibition modes.…”