ST-401, a microtubule-targeting agent (MTA), functions as a brain-penetrant microtubule (MT) assembly inhibitor. It disrupts microtubule (MT) function by gently and reversibly reducing MT assembly, which leads to mitotic delay and interphase cell death. ST-401 demonstrates potent antitumor activity.

ST-401, a hybrid molecule comprising secondary alcohol and quinoline structures, competitively inhibits the binding of [3H]colchicine to microtubule proteins by 89%. In turbidity assays, ST-401 restricts the assembly of microtubule proteins with an IC50 of 1.1 µM. Moreover, in precipitation assays measuring the release of free microtubule proteins, an IC50 of 3.2 µM was observed. This compound demonstrates low nanomolar antitumor activity across a variety of human cancer cell lines, particularly in six glioma lines (SF-268, SF-295, SF-539, SNB-19, SNB-75, and U251) with IC50 values ranging from 23-69 nM. It also exhibits low nanomolar antitumor efficacy in PD-gliomas (IC50: 24-47 nM). After 72 hours, ST-401 significantly reduces overall cell viability in MGG8 and T98G cells, with comparable IC50 values of 14 and 36 nM respectively.

ST-401 demonstrated significant antitumor activity without excessive toxicity in a heterotopic flank tumor model in nude mice when administered at a dosage of 20 mg/kg (intraperitoneal injection; twice daily; 5 days per week for 4 weeks). In this model, nude mice aged 10-14 weeks were injected with COLO205 cells. The compound was administered intraperitoneally twice daily, five days a week for four weeks, resulting in notable antitumor effects.