Probing the Relationship between Anti-Pneumocystis carinii Activity and DNA Binding of Bisamidines by Molecular Dynamics Simulations

The anti-Pneumocystis carinii activity of 13 synthetic pentamidine analogs was analyzed. The experimental differences in melting points of DNA dodecamer 5'-(CGCGAATTCGCG)2-3' complexes (ΔTm), and in the biological activity measured using ATP bioluminescence assay (IC50) together with the theoretical free energy of DNA-ligand binding estimated by the proposed computational protocol, showed that the experimental activity of the tested pentamidines appeared to be due to the binding to the DNA minor groove with extended AT sequences. The effect of heteroatoms in the aliphatic linker, and the sulfonamide or methoxy substituents on the compound inducing changes in the interactions with the DNA minor groove was examined and was correlated with biological activity. In computational analysis, the explicit solvent approximation with the discrete water molecules was taken into account, and the role of water molecules in the DNA-ligand complexes was defined

Drug Repurposing to Inhibit Histamine <i>N</i>-Methyl Transferase

Lower activity of the histaminergic system is associated with neurological disorders, including Alzheimer’s disease (AD). Thus, the enhancement of histaminergic neurotransmission by inhibition of histamine N-methyl transferase (HNMT), which degrades histamine, appears as an important approach. For this purpose, rigid and flexible molecular docking studies of 185 FDA-approved drugs with the HNMT enzyme were carried out to select two compounds to perform molecular dynamics (MD) simulations to evaluate the binding free energies and stability of the enzyme–drug complexes. Finally, an HNMT inhibition assay was performed to corroborate their effect towards HNMT. Molecular docking studies with HNMT allowed the selection of dihydroergotamine and vilazodone since these molecules showed the lowest Gibbs free energy values. Analysis of the binding mode of vilazodone showed interactions with the binding pocket of HNMT with Glu28, Gln143, and Asn283. In contrast, dihydroergotamine binds to the HNMT active site in a different location, apparently because it is overall the more rigid ligand compared to flexible vilazodone. HNMT inhibitory activity for dihydroergotamine and vilazodone was corroborated (IC50 = 72.89 μM and 45.01 μM, respectively) by in vitro assays. Drug repurposing of HNMT was achieved by employing computational studies

In Vitro and Computational Studies of Perezone and Perezone Angelate as Potential Anti-Glioblastoma Multiforme Agents

Glioblastoma multiforme (GBM) represents the most malignant type of astrocytoma, with a life expectancy of two years. It has been shown that Poly (ADP-ribose) polymerase 1 (PARP-1) protein is over-expressed in GBM cells, while its expression in healthy tissue is low. In addition, perezone, a phyto-compound, is a PARP-1 inhibitor with anti-neoplastic activity. As a consequence, in the present study, both in vitro and computational evaluations of perezone and its chemically related compound, perezone angelate, as anti-GBM agents were performed. Hence, the anti-proliferative assay showed that perezone angelate induces higher cytotoxicity in the GBM cell line (U373 IC50 = 6.44 μM) than perezone (U373 IC50 = 51.20 μM) by induction of apoptosis. In addition, perezone angelate showed low cytotoxic activity in rat glial cells (IC50 = 173.66 μM). PARP-1 inhibitory activity (IC50 = 5.25 μM) and oxidative stress induction by perezone angelate were corroborated employing in vitro studies. In the other hand, the performed docking studies allowed explaining the PARP-1 inhibitory activity of perezone angelate, and ADMET studies showed its probability to permeate cell membranes and the blood–brain barrier, which is an essential characteristic of drugs to treat neurological diseases. Finally, it is essential to highlight that the results confirm perezone angelate as a potential anti-GBM agent