Inhibition of mouse wild type PI3Kalpha expressed in Sf21 cells co-expressing N-terminal His-tagged human p85a using L-alpha-phosphatidylinositol substrate by TLC based phosphor imaging
Inhibition of mouse PI3K alpha expressed in insect cells coexpressing p85 subunit assessed as PI(3,4,5)P3 formation using PI(4,5)P2 as substrate by measuring displacement of TAMRA-labeled PI(3,4,5)P3 from Grip1 PH domain after 35 mins by ligand displacement fluorescence polarization assay
Cell Based Assay: This assay was used to measure PI3K-alpha inhibition in cells. BT474 cells (human breast ductal carcinoma, ATCC HTB-20) were seeded into black 384 well plates (Costar, #3712) at a density of 5600 cells/well in DMEM containing 10% FBS and 1% glutamine and allowed to adhere overnight.The following morning compounds in 100% DMSO were added to assay plates by acoustic dispensing. After a 2 hour incubation at 37 C. and 5% CO2, the medium was aspirated and the cells were lysed with a buffer containing 25 mM Tris, 3 mM EDTA, 3 mM EGTA, 50 mM sodium fluoride, 2 mM Sodium orthovanadate, 0.27M sucrose, 10 mM beta-glycerophosphate, 5 mM sodium pyrophosphate, 0.5% Triton X-100 and complete protease inhibitor cocktail tablets (Roche #04 693 116 001, used 1 tab per 50 ml lysis buffer).After 20 minutes, the cell lysates were transferred into ELISA plates (Greiner #781077) which had been pre-coated with an anti total-AKT antibody in PBS buffer.
Inhibition of PI3Kalpha in mouse NIH-3T3 cells assessed as reduction in PDGF-BB-induced phosphorylation of AKT at Thr308 residues preincubated for 1 hr followed by PDGF-BB stimulation and measured after 10 mins by PAGE analysis
Inhibition of PI3Kalpha in mouse NIH/3T3 cells assessed as reduction in PDGF-BB stimulated AKT T308 phosphorylation up to 3 uM incubated for 1 hr by Western blot analysis
Inhibition of PI3K p110alpha in mouse embryonic fibroblast cells assessed as reduction in PDGF-induced AKT phosphorylation at S473 residue preincubated for 2 hrs followed by PDGF stimulation and measured after 10 mins