Kinase experiment:

Aurora A kinase assays are performed using a 25 μL reaction volume (25 mM β-glycerophosphate, 20 mM Tris/HCl, pH 7.5, 5 mM EGTA, 1 mM DTT, 1 mM Na3VO4, 10 μg of kemptide (peptide substrate)), and recombinant aurora A kinase is diluted in 20 mM Tris/HCl, pH 8, containing 0.5 mg/mL BSA, 2.5% glycerol, and 0.006% Brij-35. Reactions are started by the addition of 5 μL Mg/ATP mix (15 mM MgCl4, 100 μM ATP, with 18.5 kBq γ-32P-ATP per well) and incubated at 30℃ for 30 min before terminating by the addition of 25 μL of 75 mM H3PO4. Aurora B kinase assays are performed as for aurora A except that prior to use, aurora B is activated in a separate reaction at 30℃ for 60 min with inner centromeres protein[1].

Cell experiment:

CYC-116 is prepared in DMSO and diluted in cell medium[1].

Animal experiment:

Mice: Mice implanted intraperitoneally with P388/0 cells are treated with CYC-116, and the antitumor activity is measured as an increase in lifespan of the treated animals versus the vehicle control group[1].

IC50: 44 and 19 nM respectively for Aurora A and B in cancer cells

Ki: 8.0 and 9.2 nM for aurora A and B, respectively

The aurora kinases are a family of serine-threonine kinases that interact with components of the mitotic apparatus and that regulate aspects of centrosome maturation, bipolar spindle assembly, chromosome segregation, and cytokinesis. CYC116 has been discoverd as a novel N-phenyl-4-(thiazol-5-yl) pyrimidin-2-amine aurora kinase inhibitor.

In vitro: The anticancer effects of CYC116 were shown to emanate from cell death following mitotic failure and increased polyploidy as a consequence of cellular inhibition of aurora A and B kinases. Moreover, CYC116 was also assessed against other kinases [1].

In vivo: Preliminary in vivo assessment showed that CYC116 was orally bioavailable and possessed anticancer activity. The mean relative tumor volumes of mice receiving CYC116 at both dose levels were less than those of vehicle-treated mice for the duration of the study period [1].

Clinical trials: CYC116 is currently undergoing evaluation in Phase I clinical trials.

Reference:
[1] Wang S, Midgley CA, Scaerou F, Grabarek JB, Griffiths G, Jackson W, Kontopidis G, McClue SJ, McInnes C, Meades C, Mezna M, Plater A, Stuart I, Thomas MP, Wood G, Clarke RG, Blake DG, Zheleva DI, Lane DP, Jackson RC, Glover DM, Fischer PM.   Discovery of N-phenyl-4-(thiazol-5-yl)pyrimidin-2-amine aurora kinase inhibitors. J Med Chem. 2010;53(11):4367-78.