IC50 |
10 nM, 10 nM, 10 nM, 10 nM, 10 nM, 10 nM |
In vitro |
PIK-294 shows distinct patterns of isoform selectivity to inhibit different subsets of class I PI3K isoforms (p110beta, p110delta, and p110gamma) and exhibits low sensitivity to p110alpha with IC50 of 10 uM). The m-phenol moiety of PIK-294 is able to penetrate the deep-affinity pocket of the ATP binding site, and thus increases in vitro inhibitory activity. [1] |
Kinase Assay |
Assay of p110alpha/p85alpha, p110beta/p85alpha, p110delta/p85alpha, and p110gamma, IC50 values are measured using either a standard TLC assay for lipid kinase activity or a high-throughput membrane capture assay. Kinase reactions are performed by preparing a reaction mixture containing kinase, inhibitor (2% DMSO final concentration), buffer (25 mM HEPES, pH 7.4, 10 mM MgCl2), and freshly sonicated phosphatidylinositol (100 ug/mL). Reactions are initiated by the addition of ATP containing 10 uCi of gamma-32P-ATP to a final concentration 10 uM or 100 uM, and allowed to proceed for 20 minutes at room temperature. For TLC analysis, reactions are then terminated by the addition of 105 uL 1N HCl followed by 160 uL CHCl3:MeOH (1:1). The biphasic mixture is vortexed, briefly centrifuged, and the organic phase transferred to a new tube using a gel loading pipette tip precoated with CHCl3. This extract is spotted on TLC plates and developed for 3-4 hours in a 65:35 solution of n-propanol:1M acetic acid. The TLC plates are then dried, exposed to a phosphorimager screen, and quantitated. For each compound, kinase activity is typically measured at 10-12 inhibitor concentrations representing two-fold dilutions from the highest concentration tested (100 uM). For compounds showing significant activity, IC50 determinations are repeated two to four times, and the reported value is the average of these independent measurements. |
Picture Description 1 |
, , Dr. Zhang of Tianjin Medical University, PIK-294purchased from Selleck, After starved in serum-free medium for 24 h, A549 cells incubated with the indicated concentrations of PIK-294 for 3 h, followed by 20-minute stimolation of 100ng/ml EGF. |