Ispinesib (SB-715992) is a selective inhibitor of KSP with IC50 value of 0.5 nM [1].
Kinesin spindle protein (KSP) is a kinesin motor protein and plays an important role in the formation of a bipolar mitotic spindle and cell cycle progression through mitosis. It has been shown that abnormal expression of KSP is correlated with a variety of human cancers and its inhibitors may be a promising anticancer agent [2] [3].
Ispinesib (SB-715992) is a potent KSP inhibitor and often combines with chemotherapy drugs to tumor treatment. When tested with a panel of 23 tumor cell lines, Ispinesib (SB-715992) treatment showed high activity to inhibit KSP in most of the cell lines while only Rh18 having an IC50 value greater than 1 μM (median IC50=4.1 nM, maximum IC50=0.5 nM) by using PPTP method [1]. In a panel of 53 breast cell lines, Ispinesib (SB-715992) exhibits broad antiproliferative activity and up-regulated the expression of both mitotic and apoptotic markers in MDA-MB-468 cell line [2]. When tested with PC-3 cells, Ispinesib (SB-715992) treatment inhibits cell proliferation, inducs cell apoptosis and up-regulated the expressions of genes that related to the control of cell proliferation, cell cycle, cell signaling pathways and apoptosis [3].
In mouse model with 26 tumor cells subcutaneous xenograft, administration of Ispinesib (SB-715992) inducs markedly tumor growth delay with the percent of 88% (23/26) and maintained completed response (CR) in the rhaboid tumor, Wilms tumor and Ewing sarcoma xenograft mouse model [1].
References:
[1]. Carol, H., et al., Initial testing (stage 1) of the kinesin spindle protein inhibitor ispinesib by the pediatric preclinical testing program. Pediatr Blood Cancer, 2009. 53(7): p. 1255-63.
[2]. Purcell, J.W., et al., Activity of the kinesin spindle protein inhibitor ispinesib (SB-715992) in models of breast cancer. Clin Cancer Res, 2010. 16(2): p. 566-76.
[3]. Davis, D.A., et al., Increased therapeutic potential of an experimental anti-mitotic inhibitor SB715992 by genistein in PC-3 human prostate cancer cell line. BMC Cancer, 2006. 6: p. 22.
