Binding Assay: The efficacy of compounds of the invention in inhibiting the PI3K induced-lipid phosphorylation may be tested in the following binding assay. The assay combines the scintillation proximity assay technology (SPA, Amersham) with the capacity of neomycin (a polycationic antibiotic) to bind phospholipids with high affinity and specificity. The Scintillation Proximity Assay is based on the properties of weakly emitting isotopes (such as 3H, 125I, 33P). Coating SPA beads with neomycin allows the detection of phosphorylated lipid substrates after incubation with recombinant PI3K and radioactive ATP in the same well, by capturing the radioactive phospholipids to the SPA beads through their specific binding to neomycin. To a 384 wells MTP containing 5 ul of the test compound of Formula (I) (solubilized in 2% DMSO; to yield a final concentration of 20, 5, 1.25, 0.3125, 0.0781, 0.0195, 0.0049, 0.0012, 0.0003 and 0.00075 uM of the test compound).
Inhibition of PI3K in human PBMC assessed as decrease in anti-CD3-stimulated Akt phosphorylation at S473 preincubated for 15 mins followed by anti-CD3 stimulation measured after 5 to 15 mins by phosflow method