Molecular Weight(MW): 553.52
SB743921 is a kinesin spindle protein (KSP) inhibitor with Ki of 0.1 nM, almost no affinity to MKLP1, Kin2, Kif1A, Kif15, KHC, Kif4 and CENP-E. Phase 1/2.
Cited by 7 Publications
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HeLa cells expressing iRFP were seeded onto 96-well plates and incubated with buffer or different concentrations of SB743921.During the next ﬁve days, the plate was scanned with an infrared imaging system (upper panel) to quantify the infrared signals (lower panel).
Mol Oncol 2014 8(8):1404-18. SB743921 purchased from Selleck.
SB743921 inhibits MEK/ERK and AKT signaling in CML cells. Western blot analysis was performed on lysates from KCL22 cells treated with SB743921 (0.5 nM, 1 nM, 3 nM) to examine levels of ERK phosphorylation in comparison to levels of total ERK, and AKT phosphorylation in comparison to levels of total AKT. GAPDH was used as a control to ensure equivalent protein loading.
Leuk Lymphoma 2014 1-8. SB743921 purchased from Selleck.
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|Description||SB743921 is a kinesin spindle protein (KSP) inhibitor with Ki of 0.1 nM, almost no affinity to MKLP1, Kin2, Kif1A, Kif15, KHC, Kif4 and CENP-E. Phase 1/2.|
The Ki of SB 743921 for human and mouse KSP is 0.1 nM and 0.12 nM, respectively, while the Ki of SB 743921 for other kinesins including MKLP1, Kin2 is more than 70 μM. SB 743921 blocks assembly of a functional mitotic spindle, thereby causing cell cycle arrest in mitosis and subsequent cell death. SB-743921 has improved potency over ispinesib in both biochemical and cellular assays. 
|In vivo||SB-743921 is greater efficacy in vivo against P388 leukemia. SB-743921 has significant efficacy in a broad spectrum of tumor models differing from that of taxanes. SB-743921 is shown to have activity against advanced human tumor xenografts Colo205 (complete regressions), MCF-7, SK-MES, H69, OVCAR-3 (complete and partial regressions), and HT-29, MX-1, MDA-MB-231, A2780 (tumor growth delay). SB-743921 doesn't cause the neuropathy often associated with the tubulin agents. |
Biochemistry assay:The motor domains of KSP (amino acids 1–360) is expressed as in Escherichia coli BL21(DE3) as COOH-terminal 6-his fusion proteins. Bacterial pellets are lysed in a microfluidizer with a lysis buffer [50 mM Tris-HCl; 50 mM KCl, 10 mM imidazole, 2 mM MgCl2, 8 mM β-mercaptoethanol, 0.1 mM ATP (pH 7.4)], and proteins are purified using Ni-NTA agarose affinity chromatography, with an elution buffer consisting of 50 mM PIPES, 10% sucrose, 300 mM imidazole, 50 mM KCl, 2 mM MgCl2, mM β-mercaptoethanol, and 0.1 mM ATP (pH 6.8). Steady-state measurements of ATPase activity are performed with a pyruvate kinase–lactate dehydrogenase detection system that coupled the appearance of ADP with oxidation of NADH. Absorbance changes are monitored at 340 nm. All biochemical experiments are performed in PEM25 buffer [25 mM Pipes/KOH (pH 6.8), 2 mM MgCl2, 1 mM EGTA] supplemented with 10 μM SB 743921 for experiments involving microtubules. Rates of ADP release are measured in a stopped-flow apparatus; the decrease in fluorescence of MANT-ATP is monitored. Rates of Pi release are measured in a stopped-flow apparatus, using bacterial phosphate binding protein modified with 7-diethylamino-3-((((2 maleimidyl)ethyl)amino)carbonyl)coumarin (MDCC) dye. Ki estimates of KSP inhibitors are extracted from the dose–response curves, with explicit correction for enzyme concentration. Tubulin polymerization by measuring changes in absorbance at 340 nm is monitored. The assay is performed in 100-μL volumes in 96-well half-area microtiter plates, using a microplate reader with the incubation temperature set at 37 °C.
|In vitro||DMSO||111 mg/mL (200.53 mM)|
|Ethanol||111 mg/mL (200.53 mM)|
|Water||22 mg/mL (39.74 mM)|
|In vivo||Saline pH5.0||30 mg/mL|
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