External ID: TargetID_659_CEMA

Protocol: Black, standard capacity streptavidin-coated 384-well plates (Pierce 15407) were first washed with 50 L of phosphate buffer (100 mM, pH 7.0; PB7) three times using a Biotek 405 ELX plate washer. Subsequently, 5 L of biotinylated pre-miRNA substrate (500 nM final) was dispensed into the plate using a Multidrop Combi Reagent Dispenser (Thermo Scientific). Plates were then centrifuged for 1 min at 1,000 RPM (223 g), sealed with plate tape, and incubated overnight at 4 C. The following morning, plates were washed three times with 50 L of PB7, followed by the addition of 5 L of Dicer digest buffer (20 mM Tris, 12 mM NaCl, 2.5 mM MgCl2, 1 mM fresh DTT, and 4.5% DMSO) and centrifugation. Compounds (50 nL of 5 mM DMSO stock, 25 M final) were then added into the sample wells using a Sciclone (Caliper) liquid handler with V&P pintool; the same volume of DMSO was added to the control wells. The plates were incubated at 25 C for 15 min before addition of 5 L of digest buffer containing 217 g/nL Dicer (108 g/mL Dicer, 5% glycerol and 0.01% Triton X-100 final, excess with respect to pre-miRNA). For the positive control wells, digest buffer without Dicer was added. The plates were centrifuged again and resealed before being placed in a 37 C incubator for 5 h. After Dicer cleavage, plates were washed three times with 50 L of PB7. mTet-HRP in PB7 (10 L, 750 nM final) was then dispensed into each well. The plates were subsequently centrifuged, sealed, and incubated at 25 C for 2 h. Plates were then washed three times with 50 L of wash buffer (2 mM imidazole, 260 mM NaCl, 0.5 mM EDTA, 0.1% Tween-20, pH 7.0), followed by washing three additional times with 50 L of PB7. Finally, SuperSignal West Pico (25 L; Pierce) was added, the plates were incubated at 25 C for 5 min, and chemiluminescence signal was detected using a PHERAstar plate reader using LUM plus module (BMG Labtech).

Comment: The activity outcome is based on a Z-score (number of standard deviations from the negative control mean) of 3 or higher on at least 50% times that the sample was screened.

For instance, if the sample was screened in n=4 runs, it would be considered active only if it had a Z-score of 3 or above in at least 2 runs.

External ID: MScreen:TargetID_600

Protocol: C-terminally 6xHis tagged CDK2/Cyclin A complex and N-terminally Flag tagged CDC25B C473S (372-566) were expressed and purified. Proteins were incubated together at a final concentration of 125 nM each for 1 hr prior to incubation with compound for 1 hr, followed by addition of anti-6xHis europium cryptate donor beads (Cisbio) and anti-Flag XL-665 acceptor beads (Cisbio) at a final dilution of 1:350 for 1 hr. 20mM potassium fluoride was added 10 minute prior to plate reading. Assay reagents were dispensed using a multidrop liquid dispenser (Thermo Scientific) onto uncoated, black, low-volume, 384-well plates (Corning). Assay plates were quantified using an Envision plate reader (Perkin-Elmer) with excitation of the europium crytate donor at 337 nm wavelength and emission of the donor at 620 nm and emission of the XL-665 acceptor at 665 nm in 18 uL volumes. Assays were performed in a buffer containing 50 mM Tris (pH 7.5), 50 mM NaCl, 10mM MgCl2, 1mM TCEP, with addition of and 1mM ATP, 0.05% BSA, and 0.05% Tween-20 immediately prior to the start of the assay.

Comment: The activity outcome is based on a Z-score (number of standard deviations from the negative control mean) of 3 or higher on at least 50% times that the sample was screened.
For instance, if the sample was screened in n=4 runs, it would be considered active only if it had a Z-score of 3 or above in at least 2 runs.

This screen was funded by NIH grant number: R01CA181185