Design, synthesis, and antitumor evaluation of quinazoline-4-tetrahydroquinoline chemotypes as novel tubulin polymerization inhibitors targeting the colchicine site

We designed, synthesized, and evaluated the antitumor activity of a series of novel quinazoline-4-(6-methoxytetrahydroquinoline) analogues. Among the tested compounds, 4a4 exhibited the most potent antiproliferative activities across four human cancer cell lines with half-maximal inhibitory concentration (IC50) values ranging from 0.4 to 2.7 nM, more potent than the lead compound. The 2.71 Å resolution co-crystal structure of 4a4 with tubulin (PDB code: 8YER) confirmed its critical binding at the colchicine site. Moreover, 4a4 inhibited the polymerization of tubulin, colony formation, and tumor cell migration, while inducing G2/M phase arrest and apoptosis. In vivo, 4a4 significantly delayed primary tumor growth in the SKOV3 xenograft model without obvious side effect. Our research enhances the structure-activity relationships (SARs) understanding of the quinazoline-4-tetrahydroquinoline scaffold and provides new insights for potential structural optimization and the development of novel colchicine binding site inhibitors (CBSIs). [Display omitted] •Quinazoline-4-tetrahydroquinoline analogues were designed for antitumor evaluation.•4a4 stood out for further study after structure-activity relationship investigation.•4a4 targets colchicine binding site proved by co-crystal structure with tubulin.•4a4 inhibits tubulin polymerization, resulting in G2/M phase arrest and apoptosis.•4a4 inhibits colony formation, cell migration, and tumor growth in xenograft model.