Design, synthesis, in vitro and in silico evaluation of a new series of oxadiazole-based anticancer agents as potential Akt and FAK inhibitors.

In the current work, new 1,3,4-oxadiazole derivatives were synthesized and investigated for their cytotoxic effects on A549 human lung adenocarcinoma, C6 rat glioma and NIH/3T3 mouse embryonic fibroblast cell lines. Compounds 2, 6 and 9 were found to be the most potent anticancer agents against A549 and C6 cell lines and therefore their effects on apoptosis, caspase-3 activation, Akt, FAK, mitochondrial membrane potential and ultrastructural morphological changes were evaluated. N-(5-Nitrothiazol-2-yl)-2-[[5-[((5,6,7,8-tetrahydronaphthalen-2-yl)oxy)methyl]-1,3,4-oxadiazol-2-yl]thio]acetamide (9) increased early and late apoptotic cell population in A549 and C6 cells more than cisplatin and caused more mitochondrial membrane depolarization in both cell lines than cisplatin. On the other hand, N-(6-methoxybenzothiazol-2-yl)-2-[[5-[((5,6,7,8-tetrahydronaphthalen-2-yl)oxy)methyl]-1,3,4-oxadiazol-2-yl]thio]acetamide (6) caused higher caspase-3 activation than cisplatin in both cell lines. Compound 6 showed significant Akt inhibitory activity in both cell lines. Moreover, compound 6 significantly inhibited FAK (Phospho-Tyr397) activity in C6 cell line. Molecular docking simulations demonstrated that compound 6 fitted into the active sites of Akt and FAK with high affinity and substrate-specific interactions. Furthermore, compounds 2, 6 and 9 caused apoptotic morphological changes in both cell lines obtained from micrographs by transmission electron microscopy. A computational study for the prediction of ADME properties of all compounds was also performed. These compounds did not violate Lipinski's rule, making them potential orally bioavailable anticancer agents.