Kinase reactions are performed in a final assay volume of 10 μL using the Z'-Lyte Assay kit (Ser/Thr peptide 16). Briefly, reactions contained 50 mM HEPES (pH 7.5), 10 mM MgCl₂, 1 mM EGTA, 1 mM DTT, 0.01% Brij 35, 0.01 mg/mL casein, 200 μM ATP, 200 μM Polo Box peptide (NH2-MAGPMQS[pT]PLNGAKK-OH), and 6 nM recombinant Plk1 (H6-tev-PLK 1-603). Plk1 is preincubated for 60 min in the presence or absence of 0 to 1,000 nM GSK461364. Reactions are then initiated by the addition of 2 μM peptide. After 15 min at 23°C, reactions are quenched and processed according the Z'-Lyte protocol and read on an plate reader. Raw fluorescence values are converted to concentration of product formed using substrate and product standards. IC₅₀ values are determined using a two-parameter fit (Hill coefficient and IC₅₀) using GraFit software. Because the potency of inhibition for GSK461364 is observed to vary as a function of the ATP concentration in a manner consistent with an ATP-competitive mode of inhibition, an upper limit for the K_i^*app for GSK461364 is determined by applying the Cheng-Prusoff relationship for a competitive inhibitor (ATP K_m^*app=16 μM) to the IC₅₀ value obtained with 60 min preincubation of GSK461364.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Cell lines grow in the recommended media at 37°C, 5% CO₂ in a humidified incubator. Cells are plated in triplicate 96-well microtiter plates at 1,000 cells per well in culture media. GSK461364 (GSK461364A) dissolved in DMSO or negative control (0.1% DMSO) are added the following day, and one plate is harvested with 50 μL of CellTiter-Glo for a time 0 (T=0) measurement.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Cells are implanted in Nude mice and grown as tumor xenografts. Dosing began when tumors achieve appr 100 mm³. GSK461364 (GSK461364A) or the vehicle [4% DMA/Cremaphore (50:50), pH 5.6] is given i.p. to mice every 2 d (q2d×6, q2d×12) or every 4 d (q4d×3) at nominal dose levels of 25, 50, and 100 mg/kg/dose. Results are reported as median tumor volume for n=7 to 8 mice. Paclitaxel (30 mg/kg i.v.; q4d×3) is used as a positive control for comparison. Tumors are measured thrice a week with Vernier calipers, and tumor volume is calculated from two-dimensional measurements using an equation approximating the volume of a prolate ellipsoid [tumor volume mm³=(length × width²) × 0.5]. The maximum tolerated dose is defined as the highest dose that produces >20% mortality or >20% weight loss (appr 4 g). Antitumor activity is defined as tumor growth delay (TGD), partial regression (PR), or complete regression (CR). TGD represents the time differential between the treated and control tumors to reach a predetermined tumor volume of 1,000 mm³. PR is defined as a decrease in an individual tumor volume to one-half the initial starting volume for at least 1 wk (three consecutive measurements). CR is defined as a decrease in an individual tumor volume to <13 mm³ for at least 1 wk.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

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