Structure-based approaches for the design of 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d][1,2,3]triazoles as tubulin polymerization inhibitors.

The colchicine binding site on tubulin has been widely acknowledged as an attractive target for anticancer drug exploitation. Here, we reported the structural optimization of the lead compound 4, which was proved in our previous work as a colchicine binding site inhibitor (CBSI). Based on docking researches for the active binding conformation of compound 4, a series of novel 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d][1,2,3]triazole derivatives (9a-9x) were developed by replacing a CH group in the 1H-benzo[d]imidazole skeleton of compound 4 with a nitrogen atom as a hydrogen bond acceptor. Among them, compound 9a showed the strongest antiproliferative activity with IC50 values ranging from 14 to 45 nM against three human cancer cell lines (MCF-7, SGC-7901 and A549), lower than that of compound 4. Mechanistic studies indicated that compound 9a could inhibit tubulin polymerization, destroy the microtubule skeleton, block the cell cycle in G2/M phase, induce cancer cell apoptosis, prevent cancer cell migration and colony formation. Moreover, compound 9a significantly inhibited tumor growth in vivo without observable toxicity in the mice 4T1 xenograft tumor model. In conclusion, this report shows a successful case of the structure-based design approach of a potent tubulin polymerization inhibitor for cancer treatment.

Design, synthesis and biological evaluation of colchicine glycoconjugates as tubulin polymerization inhibitors.

A series of new colchicine glycoconjugates as tubulin polymerization inhibitors were designed by targeting strategy based on Warburg effect. All of the colchicine glycoconjugates were synthesized and then evaluated for their antiproliferative activities against three human cancer lines HT-29, MCF-7 and Hep-3B. Among them, 1e exhibited greater than 10 times selectivity between GLUT1 highly expressed cells (HT-29 and MCF-7) and GLUT1 lowly expressed cells (Hep-3B), and also showed lower cytotoxicity against HUVECs compared with colchicine. Moreover, 1e significantly inhibited tubulin polymerization and disrupted microtubule networks. GLUT1 inhibitor-dependent cytotoxicity assay demonstrated that the uptake of 1e was regulated via GLUT1. Molecular docking studies showed that 1e could be a substrate of GLUT1 and bind to the colchicine site of tubulin.

Design, synthesis and bioevaluation of 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d]imidazoles as tubulin polymerization inhibitors.

A series of new 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d]imidazoles as tubulin polymerization inhibitors targeting the colchicine-binding site were designed to restrict bioactive configuration of (Z,E)-vinylogous CA-4. All of the target compounds were synthesized and then evaluated for their in vitro antiproliferative activities. Among them, 2a exhibited the most potent activities against three cancer cell lines with IC50 values in the range of 0.037-0.20 µM. Further mechanism studies revealed that 2a inhibited tubulin polymerization, disrupted cell microtubule networks, arrested the cell cycle at G2/M phase, induced apoptosis and hindered cancer cell migration. Moreover, 2a displayed significant in vivo antitumor efficacy in 4T1-xenograft mice model with tumor growth inhibition rate of 52% at the dose of 2.5 mg/kg. Colchicine competition assay and the docking model of 2a in complex with tubulin showed that 2a acted at the colchicine-binding site.

Design, synthesis and bioevaluation of 2,7-diaryl-pyrazolo[1,5-a]pyrimidines as tubulin polymerization inhibitors.

Two series of 2,7-diaryl-pyrazolo[1,5-a]pyrimidines as tubulin polymerization inhibitors were designed to restrict bioactive configuration of (E,Z)-vinylogous CA-4. All of the target compounds were synthesized and then evaluated for their in vitro antiproliferative activities against three cancer cell lines (MCF-7, SGC-7901 and A549). Among them, 6d exhibited the most potent antiproliferative activity against the MCF-7 with IC50 value of 0.047 µM. Moreover, 6d significantly inhibited tubulin polymerization, disrupted microtubule networks, arrested cell cycle at G2/M phase, induced apoptosis and hindered cancer cell migration. Colchicine competition assay and molecular docking studies suggested that 6d could interact with tubulin by binding to the colchicine site.