Discovery and optimization of 3,4,5-trimethoxyphenyl substituted triazolylthioacetamides as potent tubulin polymerization inhibitors

[Display omitted] •Based on our previous work, 29 novel triazolylthioacetamides possessing 3,4,5-trimethoxylphenyl groups were synthesized.•8f and 8j showed potent antiproliferative activities against Hela with IC50 values of 0.04 and 0.05 μM, respectively.•8b exhibited potent antitubulin activity with IC50 values of 5.9 μM, which was proximate to CA-4 (IC50 = 4.2 μM). Based on our previous research, three series of new triazolylthioacetamides possessing 3,4,5-trimethoxyphenyl moiety were synthesized, and evaluated for antiproliferative activities and inhibition of tubulin polymerization. The most promising compounds 8b and 8j demonstrated more significant antiproliferative activities against MCF-7, HeLa, and HT-29 cell lines than our lead compound 6. Moreover, analogues 8f, 8j, and 8o manifested more potent antiproliferative activities against HeLa cell line with IC50 values of 0.04, 0.05 and 0.16 μM, respectively, representing 100-, 82-, and 25-fold improvements of the activity compared to compound 6. Furthermore, the representative compound, 8j, was found to induce significant cell cycle arrest at the G2/M phase in HeLa cell lines via a concentration-dependent manner. Meanwhile, compound 8b exhibited the most potent tubulin polymerization inhibitory activity with an IC50 value of 5.9 μM, which was almost as active as that of CA-4 (IC50 = 4.2 μM). Additionally, molecular docking analysis suggested that 8b formed stable interactions in the colchicine-binding site of tubulin.