Tubulin polymerization-IN-64 (Compound 8a) is a microtubule polymerization inhibitor that functions by occupying the colchicine binding site on tubulin, with an IC50 of 6.9 μM. This compound suppresses the proliferation of cancer cell lines A549, HeLa, HCT116, and HT-29, with IC50 values of 2.42, 10.33, 6.28, and 5.33 μM, respectively. Tubulin polymerization-IN-64 induces cell cycle arrest at the G2/M phase and triggers apoptosis in A549 cells.