An N-linked imidazo[1,2-a]pyridine benzoheterobicyclic hybrid inhibits mitosis and cancer cell proliferation by targeting tubulin

Colchicine-site agents have strong potential to be used as tubulin-targeted anticancer agents. In this study, a series of imidazo[1,2-a]pyridine-benzoheterobicyclic hybrids linked by a nitrogen atom as N-heterocyclic imines were designed as colchicine site binding agents. Cell-based assays identified two compounds, 6b (N-(3-(4-chlorophenyl)imidazo[1,2-a](pyridin-2-yl)benzo[d]thiazol-2(3H)-imine) and 6c (N-(6-chloro-3-phenylimidazo[1,2-a]pyridin-2-yl)-1,3-dihydro-2H-benzo[d]imidazol-2-imine), as the most potent antiproliferative compounds against cervical cancer (HeLa) cells. Compound 6c inhibited purified tubulin polymerization in vitro and depolymerized microtubules in HeLa and MCF-7 cells. Additionally, 6c arrested HeLa cells in the mitotic phase, increased the production of reactive oxygen species, and induced cell death. The compound also exhibited a strong binding affinity towards the colchicine binding site on tubulin. Quantum chemical analysis and molecular docking indicated that 6c preferentially binds to tubulin in its iminic tautomeric state. The chemoinformatic analysis further revealed that 6c occupies a unique and therapeutically relevant chemical space with a favorable profile regarding physicochemical properties, ADMET, and pharmacokinetics.