Assay Method Information | |
| Inhibition of PI3K alpha |
Description: | Quantification of ATP to ADP conversion as a measure of PI3Kα activity. Active PI3Kα (Life Technologies), in the presence or absence of PI3Kα inhibitor, was reacted with PIP2:PS (Life Technologies), a substrate specifically optimized for use with Class I PI3 kinases, and ultrapure ATP (Promega). The conversion of ATP to ADP by PI3Kα was measured as luminescence signal via Promega ADP-Glo kinase activity assay. Assay was validated using published PI3Kα inhibitors LY294002, PI-103, BYL719, GDC0198 and also DMSO vehicle control.Compounds were prepared at 100× final concentration as a 12-point, 1:3 serial-dilution in DMSO series, with DMSO control as 12th point. Compound was then diluted in (25 mM HEPES pH 7.5, 1 mM EGTA, 0.3% CHAPS) prior to addition to PI3Kα. Active PI3Kα diluted to 0.24 ng/μL (1.1 nM) in (50 mM HEPES pH 7.5, 6 mM MgCl2, 1 mM EGTA, 200 mM NaCl, 0.03% CHAPS, 8 mM DTT) was incubated with compound for 0 hr and 3 hr prior to the start of the reaction. 25 μM PIP2:PS and 60 μM ATP were diluted from stock in (25 mM HEPES pH 7.5, 1 mM EGTA, 0.3% CHAPS) and added to initiate the PI3Kα reaction. Reaction time was 30 minutes. ATP to ADP conversion was measured in Luminescence Counts on DTX880 Plate Reader (Beckman Coulter). Compound IC50s were reported using GraphPad Prism software. Analytical method was non-linear regression, 4-parameter curve fit with bottom fit to validated PI3Kα inhibitor reference controls and no top fit (floating top). |
Affinity data for this assay | |
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