Antiproliferative benzothiazoles incorporating a trimethoxyphenyl scaffold as novel colchicine site tubulin polymerisation inhibitors.

Tubulin polymerisation inhibitors exhibited an important role in the treatment of patients with prostate cancer. Herein, we reported the medicinal chemistry efforts leading to a new series of benzothiazoles by a bioisosterism approach. Biological testing revealed that compound could significantly inhibit tubulin polymerisation of a concentration dependent manner, with an IC value of 2.87 μM. Immunofluorescence and EBI competition assay investigated that compound effectively inhibited tubulin polymerisation and directly bound to the colchicine-binding site of β-tubulin in PC3 cells. Docking analysis showed that formed hydrogen bonds with residues Tyr357, Ala247 and Val353 of tubulin. Importantly, it displayed the promising antiproliferative ability against C42B, LNCAP, 22RV1 and PC3 cells with IC values of 2.81 μM, 4.31 μM, 2.13 μM and 2.04 μM, respectively. In summary, compound was a novel colchicine site tubulin polymerisation inhibitor with potential to treat prostate cancer.