S-72

S-72 is an inhibitor of microtubule polymerization.¹ It inhibits microtubule polymerization in a cell-free assay when used at concentrations 1, 3, and 10 µM. S-72 reduces viability in MCF-7 and paclitaxel-resistant MCF-7/T breast cancer cells (IC₅₀s = 15.64 and 26.32 nM, respectively). It inhibits migration and invasion, as well as the percentage of wound closure in a scratch assay, in MCF-7 and MCF-7/T cells when used at a concentration of 50 nM. S-72 (100 nM) induces cell cycle arrest at the G₂/M phase in MCF-7/T cells, as well as induces apoptosis in those same cells. It also inhibits stimulator of interferon genes (STING) activation in MCF-7/T cells when used at a concentration of 100 nM. S-72 (15 mg/kg per day) inhibits tumor growth in MCF-7/T and MX-1/T mouse xenograft models of paclitaxel-resistant breast cancer.