Ispinesib (mesylate)

Ispinesib (SB-715992) mesylate is a specific inhibitor of kinesin spindle protein (KSP), with a K_{i app} of 1.7 nM. IC50 & Target:Ki app: 1.7 nM (KSP)^[1] In Vitro:Ispinesib (150 nM) mesylate inhibits BT-474 and MDA-MB-468 cell lines, with GI₅₀s of 45 and 19 nM, respectively^[2].
Ispinesib (SB715992, 15 and 30 nM) mesylate suppresses the proliferation of PC-3 prostate cancer cell by 48.65% and 52.16%, and induces apoptosis of prostate cancer cell by 1094.88% and 1516.70%, respectively. Ispinesib mesylate up regulates genes responsible for apoptosis and cell cycle arrest, and down regulates genes responsible for cell proliferation and survival. The anti-proliferation and pro-apoptotic activities of Ispinesib mesylate can be enhanced by genistein^[3]. In Vivo:Ispinesib (SCID, 8 mg/kg; nude, 10 mg/kg, q4d × 3) mesylate reduces tumor volume in mice bearing tumor xenografts of ER-positive (MCF7), HER2-positive (KPL4, HCC1954, and BT-474), and triple-negative (MDA-MB-468) breast cancer cells via i.p. one dose every 4 days repeated three times^[2].