CHEMBL5731054

ERalpha Degradation (MCF7 Cells): Plate MCF7 cells at 0.3 million cells/mL (100 l/well) in black, clear-bottom 96-well plates (Greiner, catalog number 655090) in DMEM/F12 media (Gibco, catalog number 11330) supplemented with 10% charcoal-stripped serum (Gemini Bio-Products, catalog number 100-119), and incubate them at 37° C., 5% CO2 for 24-36 hours. Next day, make 10× solution of ligands in DMSO and add the solution to the cells to achieve a final concentration of 10 uM. A DMSO control is required for relative calculations, and fulvestrant is used as a positive control for ER degradation. The cells are subjected to the in-cell Western assay after incubating cells with ligand for 18-24 hours.Media is removed from the plates by decanting, and cells are immediately fixed with 100 μl of 3.7% formaldehyde in PBS using a multi-channel pipettor. Add formaldehyde to the sides of the wells to avoid cell disruption. Plates are incubated at room temperature for 20 minutes without shaking. The fix solution is then removed and cells are permeabilized with 100 μL/well of 0.1% Triton X-100 in PBS. The lysate is then blocked by adding 50 uL/well of blocking solution (3% goat serum, 1% BSA, 0.1% cold fish skin gelatin and 0.1% Triton X-100 in PBS, pH 7.4) and allowed to shake at room temperature for 2 hr, or alternatively, at 4° C. overnight.After blocking, 40 μL/well of the primary antibody against ERα (HC-20) (Santa cruz, catalog number 543) diluted at 1:3000 in blocking buffer diluted 1:3 with PBS is added to each well, except the negative control wells (which are used for background subtraction) and the plate is sealed and incubated overnight at 4° C. Next day, the primary antibody solution is removed and the wells are washed three times with 0.1% TWEEN in PBS, with each wash lasting 5 minutes. 40 μL/well of secondary antibody (Biotium CF770 goat anti-rabbit 1:2000, catalog number 20078) and DRAQ5 (DNA stain, 5 mM, Thermo Scientific, catalog number 62251) diluted at 1:10000 in blocking buffer diluted 1:3 with PBS is then added to all the well, including the negative control wells, and the plate is allowed to incubate on shaker at room temperature for 2 hr. The secondary antibody solution is then removed and the plates are washed three times as described above. The plate is then washed one final time with PBS alone to minimize auto-fluorescence. The plate is then cleaned and read on LiCor Odyssey imager.For % response calculations, first divide integrated intensities for 700 channel (ER) by integrated intensities for 800 channel (DNA normalization); 700 (ER)/800 (DNA). This will be referred to as the normalized value. Then subtract average of negative control wells (no primary antibody) from all normalized values. This corresponds to negative subtraction. % response=(Valueunknown/ValueDMSO control)*100.