In Silico Design and Experimental Validation of Novel Oxazole Derivatives Against Varicella zoster virus

Varicella zoster virus (VZV) infection causes severe disease such as chickenpox, shingles, and postherpetic neuralgia, often leading to disability. Reactivation of latent VZV is associated with a decrease in specific cellular immunity in the elderly and in patients with immunodeficiency. However, due to the limited efficacy of existing therapy and the emergence of antiviral resistance, it has become necessary to develop new and effective antiviral drugs for the treatment of diseases caused by VZV, particularly in the setting of opportunistic infections. The goal of this work is to identify potent oxazole derivatives as anti-VZV agents by machine learning, followed by their synthesis and experimental validation. Predictive QSAR models were developed using the Online Chemical Modeling Environment (OCHEM). Data on compounds exhibiting antiviral activity were collected from the ChEMBL and uploaded in the OCHEM database. The predictive ability of the models was tested by cross-validation, giving coefficient of determination q2 = 0.87-0.9. The validation of the models using an external test set proves that the models can be used to predict the antiviral activity of newly designed and known compounds with reasonable accuracy within the applicability domain (q2 = 0.83-0.84). The models were applied to screen a virtual chemical library with expected activity of compounds against VZV. The 7 most promising oxazole derivatives were identified, synthesized, and tested. Two of them showed activity against the VZV Ellen strain upon primary in vitro antiviral screening. The synthesized compounds may represent an interesting starting point for further development of the oxazole derivatives against VZV. The developed models are available online at OCHEM http://ochem.eu/article/145978 and can be used to virtually screen for potential compounds with anti-VZV activity.

Synthesis, characterization of novel N-(4-cyano-1,3-oxazol-5-yl)sulfonamide derivatives and in vitro screening their activity against NCI-60 cancer cell lines

A novel series of N-(4-cyano-1,3-oxazol-5-yl)sulfonamides have been synthesized and characterized by IR, 1 H NMR, 13 C NMR spectroscopy, elemental analysis and chromato-mass-spectrometry. The anticancer activities of all newly synthesized compounds were evaluated via a single high-dose assay (10 μM) against 60 cancer cell lines by the National Cancer Institute (USA) according to its screening protocol. Among them, compounds 2 and 10 exhibited the highest activity against the 60 cancer cell lines panel in the one-dose assay. Compounds 2 and 10 showed inhibitory activity within the GI50 parameter and in five dose analyses. However, their cytostatic activity was only observed against some cancer cell lines, and cytotoxic concentration was outside the maximum used, i. e., >100 μM. The COMPARE analysis showed that the average graphs of the tested compounds have a moderate positive correlation with compounds with the L-cysteine analog and vinblastine (GI50 ) as well as paclitaxel (TGI), which target microtubules. Therefore, disruption of microtubule formation may be one of the mechanisms of the anticancer activity of the tested compounds, especially since among tubulin inhibitors with antitumor activity, compounds with an oxazole motif are widely represented. Therefore, N-(4-cyano-1,3-oxazol-5-yl)sulfonamides may be promising for further functionalization to obtain more active compounds.

Design and experimental validation of the oxazole and thiazole derivatives as potential antivirals against of human cytomegalovirus

QSAR studies of a set of previously synthesized azole derivatives tested against human cytomegalovirus (HCMV) were performed using the OCHEM web platform. The predictive ability of the classification models has a balanced accuracy (BA) of 73-79%. The validation of the models using an external test set proved that the models can be used to predict the activity of newly designed compounds with a reasonable accuracy within the applicability domain (BA = 76-83%). The models were applied to screen a virtual chemical library with expected activity of compounds against HCMV. The five most promising new compounds were identified, synthesized and their antiviral activities against HCMV were evaluated in vitro. Two of them showed some activity against the HCMV strain AD169. According to the results of docking analysis, the most promising biotarget associated with HCMV is DNA polymerase. The docking of the most active compounds 1 and 5 in the DNA polymerase active site shows calculated binding energies of -8.6 and -7.8 kcal/mol, respectively. The ligand's complexation was stabilized by the formation of hydrogen bonds and hydrophobic interactions with amino acids Lys60, Leu43, Ile49, Pro77, Asp134, Ile135, Val136, Thr62 and Arg137.