Design, synthesis and biological evaluation of novel acridine and quinoline derivatives as tubulin polymerization inhibitors with anticancer activities

A series of acridine and quinoline derivatives were designed and synthesized based on our previous work as novel tubulin inhibitors targeting the colchicine binding site. Among them, compound 3b exhibited the highest antiproliferative activity with an IC₅₀ of 261 nM against HepG-2 cells (the most sensitive cell line). In addition, compound 3b was able to suppress the formation of HepG-2 colonies. Mechanism studies revealed that compound 3b effectively inhibited tubulin polymerization in vitro and disrupted microtubule dynamics in HepG-2 cells. Furthermore, compound 3b inhibited the migration of Cancer cells in a dose dependent manner. Moreover, compound 3b induced cell cycle arrest in G2/M phase and led to cell Apoptosis. Finally, docking studies demonstrated that compound 3b fitted nicely in the colchicine binding site of tubulin and overlapped well with CA-4. Collectively, these results suggested that compound 3b represents a novel tubulin inhibitor deserving further investigation.