Ispinesib (SB-715992)

517, 06

Nude (nu/nu) mice models of MCF7, KPL4, and HCC1954 cells, severe combined immunodeficient (SCID) mice model of MDA-MB-468 cells,

Investigations of Ispinesib in multiple Phase II clinical trials for several cancers, including kidney, prostate, colorectal, liver, ovarian, and breast cancers, have been completed.

10 mg/kg for nude mice or 8 mg/kg for SCID mice

1.7 nM (Ki app), [1], 1.7 nM (Ki app), [1], 1.7 nM (Ki app), [1], 1.7 nM (Ki app), [1], 1.7 nM (Ki app), [1], 1.7 nM (Ki app), [1]

Ispinesib (4.5 mg/kg–15 mg/kg) exhibits inhibitory effects against Colo205, Colo201, HT-29, but not MX-1 cells, in mouse xenograft models. SB-715992 (6 mg/kg–10 mg/kg ) also inhibits murine solid tumors, including Madison 109 lung carcinoma, M5076 sarcoma, as well as L1210 and P388 leukemias. [2] In mice xenograft models of breast cancer cells MCF-7, HCC1954, MDA-MB-468, and KPL4, Ispinesib (8 mg/kg–10 mg/kg) inhibits tumor growth. [4]

Steady-State Kinetic Analysis of Human KSP ATPase Activity and Inhibition by Ispinesib, Kinesin specificity analysis is carried out using a pyruvate kinase-lactate dehydrogenase detection system that couples the production of ADP to oxidation of NADH. Absorbance changes are monitored at 340 nm. Steady-state studies using nanomolar concentrations of KSP are performed using a sensitive fluorescence-based assay utilizing a pyruvate kinase, pyruvate oxidase, and horseradish peroxidase (HRP) coupled detection system that couples the generation of ADP to oxidation of Amplex Red to fluorescent resorufin. Generation of resorufin is monitored by fluorescence (lambdaexcitation = 520 nm and lambdaemission = 580 nm). Steady-state biochemical experiments are performed in PEM25 buffer [25 mM Pipes-K+ (pH 6.8), 2 mM MgCl2, 1 mM EGTA] supplemented with 10 uM paclitaxel for experiments involving microtubules. The IC50 for steady-state inhibition is determined at 500 uM ATP, 5 uM Microtubules, and 1 nM KSP in PEM25 buffer. Ki app (apparent inhibitor dissociation constant) values of Ispinesib are extracted from the dose-response curves, with explicit correction for enzyme concentration by using the Morrison equation. Inhibitor modality (e.g., competitive, noncompetitive, uncompetitive, or mixed) under steady-state conditions is determined by measuring the effect of inhibitor concentration on initial velocity as a function of substrate concentrations. Data are fit using equations in GraFit to velocity equations for the various modes of inhibition.

DMSO 103 mg/mL, Water <1 mg/mL, Ethanol 103 mg/mL

(R)-N-(3-aminopropyl)-N-(1-(3-benzyl-7-chloro-4-oxo-3, 4-dihydroquinazolin-2-yl)-2-methylpropyl)-4-methylbenzamide