Abstract
Apparently, tubulin inhibitors binding to the colchicine-binding site (CBS) currently have outstanding attention for cancer treatment. So, a series of benzo[b]azonin-2-one derivatives having the same pharmacophoric features as colchicine binding site inhibitors (CBSIs) were synthesized targeting the CBS of beta-tubulin. The antiproliferative activities of the newly synthesized compounds were assessed against five different cancer cell lines; HepG-2, MCF-7, MDA-MB-231, HCT-116, and Caco-2. Compounds 7a and 7d displayed promising inhibitory activities against all tested cell lines. They were further estimated towards beta-tubulin at CBS along with colchicine (Col) as a reference drug. It was shown that the assessed candidates (7a and 7d) and Col exhibited CBSI activities of 5492, 3771, and 486c.p.m./mg protein, respectively, at a concentration of 10 mu M. Furthermore, compound 7d was picked out to assess its effects on apoptosis and cell-cycle profile using Annexin V-FITC and PI staining assay. In addition, the apoptotic activity of 7d was investigated using gene expression analysis of apoptosis-related genes of P53, Bax, Caspases 3 and 9, and Bcl-2 in both treated and untreated cells. Moreover, compound 7d was further assessed through in vivo studies using solid Ehrlich carcinoma (SEC)-bearing mice. Furthermore, both molecular docking and molecular dynamics simulations (for 150 ns) were performed to investigate their mechanism of action as potential CBSIs and give more insights into the behavior of the examined candidates within the beta-tubulin subunit of the CBS. On the other hand, in silico ADMET studies were carried out to assess the pharmacokinetic features, drug/lead likeness, and toxicity parameters of the newly synthesized derivatives. Finally, to anticipate the possible changes in the antimitotic activities upon future structural modifications of the investigated compounds, a structure-activity relationship study (SAR) was accomplished.