OTS964 是一种有效的TOPK抑制剂，对TOPK具有高的亲和力和选择性，IC50为28 nM。OTS964 也是 cyclin-dependent kinase CDK11 的有效抑制剂，Kd为40 nM。OTS964 处理可激活胶质瘤细胞中的自噬，并诱导小鼠异种移植物中人肺癌细胞的凋亡。 Information OTS964 OTS964 is a potent TOPK inhibitor with high affinity and selectivity and IC50 value is 28 nM. OTS964 is also a potent inhibitor of the cyclin-dependent kinase CDK11 with Kd of 40 nM. OTS964 treatment activates autophagy in glioma cells and induces apoptosis of human lung cancer cells in mouse xenografts. Targets TOPK (Cell-free assay); CDK11B (Cell-free assay) 28 nM; 40 nM(Kd) In vitro OTS964 inhibits the growth of TOPK-positive cells with low IC50 values [A549 (31 nM), LU-99 (7.6 nM), DU4475 (53 nM), MDAMB- 231 (73 nM), T47D (72 nM), Daudi (25 nM), UM-UC-3 (32 nM), HCT-116 (33 nM),MKN1 (38 nM), MKN45 (39 nM), HepG2 (19 nM), MIAPaca-2 (30 nM), and 22Rv1 (50 nM)], whereas its growth inhibitory effect against TOPK-negative HT29 cancer cells is significantly weaker, with IC50 of 290nM. Although OTS964 reveals some suppressive effect on Src family kinases, the response to OTS964 in these cancer cells is not correlated with the expression of Src family kinases c-Src, Fyn, and Lyn, supporting the TOPK-dependent growth inhibitory effects of OTS964. Time lapse imaging in T47D cells shows that treatment with OTS964 induces cytokinesis defects followed by apoptosis. In vivo Although administration of the free compound induces hematopoietic adverse reactions (leukocytopenia associated with thrombocytosis), the drug delivered in a liposomal formulation effectively causes complete regression of transplanted tumors without showing any adverse reactions in mice. Inhibition of TOPK activity with the liposomal OTS964 suppresses tumor growth through induction of cytokinesis defects and subsequent apoptosis. Although oral administration of OTS964 causes some hematopoietic toxicity, this is a transient effect. The spontaneous recovery from leukocytopenia is occured and the anticancer effectiveness of the oral drug is similar to that of the liposomal formulation, oral administration of the drug may prove to be more practical. Cell Research(from reference) Cell lines：A549 cells, LU-99 cells, DU4475 cells, MDA-MB-231 cells, T47D cells, Daudi cells, UM-UC-3 cells, HCT-116 cells, MKN1 cells, MKN45 cells, HepG2 cells, MIAPaca-2 cells, 22Rv1 cells and HT29 cells Incubation Time：72 h