CHEMBL5737682

EED-H3K27Me3 Peptide Competition Binding Assay by AlphaScreen: To assess the compounds potency in the EED-H3K27Me3 competition binding assay, compounds were serially diluted 3-fold in DMSO to obtain a total of twelve concentrations. Then compounds at each concentration (75 nL of each) were transferred by Mosquito into a 384-well Perkin Elmer ProxiPlate 384 plus plates. 8 uL of solutions containing 30 nM EED (1-441)-His protein and 15 nM biotin-H3K27Me3 (19-33) peptide in the buffer (25 mM HEPES, pH 8, 0.02% Tween-20, 0.5% BSA) were added to the wells and then incubated with compound for 20 min. AlphaScreen detection beads mix was prepared immediately before use by mixing nickel chelate acceptor beads and streptavidin donor beads in a 1:1 ratio (Perkin Elmer, Product No. 6760619C/M/R) into the buffer described above. Then 4 μL of detection beads mix was added to the plate and incubate in the dark at the rt for 1 h. The final concentration of donor and acceptor beads was 10 μg/mL for each. Plates were read on EnVision (PerkinElmer) using the AlphaScreen setting adapted for optimal signal detection with a 615 nm filter, after sample excitation at 680 nm. The emission signal at 615 nm was used to quantify compounds inhibition. AlphaScreen signals were normalized based on the reading coming from the positive (maximum signal control) and negative controls (minimum signal control) to give percentage of activities left. The data were then fit to a dose response equation using the program Helios (Novartis) to get the IC50 values. Helios is a Novartis in-house assay data analysis software using the methods described by Normolle, D. P., Statistics in Medicine, 12:2025-2042 (1993); Formenko, I. et al, Computer Methods and Programs in Biomedicine, 82, 31-37 (2006); Sebaugh, J. L., Pharmaceutical Statistics, 10:128-134 (2011); Kelly, C. et al., Biometrics, 46(4):1071-1085 (1990); and Kahm, M. et al., Journal of Statistical Software, 33(7): (2010) (grofit: Fitting Biological Growth Curves with R, pages 1-21, available at http://www.jstatsoft.org/).Each compound was counterscreened to determine if it interfered with the AlphaScreen beads. Compounds were diluted as described in the preceding section, and the assay was performed by adding 12 μL of 10 nM biotin-miniPEG-His6 peptide in the above buffer and incubating for 20 min at rt prior to addition of the beads to 10 μg/mL each. The plates were then incubated for 1 h at rt in dark before being read on EnVison.