Dexamethasone Sodium Phosphate (Dexadreson) , an interleukin receptor modulator, has anti-inflammatory and immunosuppressant effects. It belongs to a potent glucocorticoid class of steroid synthetic drugs.

Biochemical kinase assays: Recombinant His-tagged human Aurora-A protein is expressed in Escherichia coli and is purified with HisTrap HP column. Purified recombinant human Aurora-B and Aurora-C protein are purchased. Experiments are done in quintuplicate in 96-well plates. The Aurora-A assay reaction is conducted in the presence of 20 μM ATP, 25 μM Tetra-Kemptide [RRR(GLRRASLG)4R-NH2], 1.0 μCi per well [γ-33P]-ATP, 0.1 ng per well Aurora-A in 50 mM Tris-HCl (pH 7.4), 15 mM Mg(OAc)2, and 0.2 mM EDTA at 30°C for 40 minutes. To investigate the inhibition mode of MK-5108 for Aurora-A, the IC50 values of MK-5108 are determined in the presence of different concentrations of ATP. Then, the IC50 value is plotted as a function of ATP concentration to analyze the effect of ATP concentration on the IC50 value of MK-5108. The Aurora-B assay reaction is conducted in the presence of 15 μM ATP, 100 μM Kemptide (GLRRASLG-NH2), 1.0 μCi per well [γ-33P]-ATP, 5.0 ng per well Aurora-B in 50 mM Tris-HCl (pH 7.4), 15 mM Mg(OAc)2, and 0.2 mM EDTA at 30 °C for 20 minuts. The Aurora-C assay reaction is conducted in the presence of 40 μM ATP, 100 μM Kemptide, 1.0 μCi per well [γ-33P]-ATP, 15 ng per well Aurora-C in 10 mM MOPS-NaOH (pH 7.4), 5 mM Mg(OAc)2, 1 mM (±) DTT, and 1 mM EGTA at 30 °C for 20 minutes. After kinase reactions are terminated by adding 2.0% phosphoric acid, Tetra-Kemptide or Kemptide is trapped on the MultiScreen-PH plate. Wells are washed five times with 0.64% phosphoric acid and then monitored for radioactivity in a liquid scintillation counter.