WHI-P154 (Jak3 inhibitor ii) is a potent JAK3 inhibitor.

Kinase assays: WHI-P154 is tested in kinase assays. The panel of kinases is selected to broadly cover the kinome, providing a good approximation of specificity. For all kinases, recombinant rat (IKKβ) or human (all others), full-length or GST-kinase domain fusion proteins, are used. WHI-P154 is inactive (concentration that inhibits response by 50% [IC50] > 30 μM) for the following kinases: AKT, AuroraA, cdk2, cdk6, CHK1, FGFR1, GSK3b, IKKb, IKKi, INSR, MAPK1, MAPKAP-K2, MASK, MET, PAK4, PDK1, PKCb, ROCK1, TaoK3, TrkA.

Cells are seeded into a 96-well plate at a density of 2.5×104 cells/well and incubated for 36 h at 37 ℃ before drug exposure. On the day of treatment, culture medium is carefully aspirated from the wells and replaced with fresh medium containing the quinazoline compounds WHI-P154 at concentrations ranging from 0.1 μM to 250 μM. Triplicate wells are used for each treatment. The cells are incubated with the compound for 24hours to 36hours at 37 ℃ in a humidified 5% CO2 atmosphere. To each well, 10 μL of MTT (final concentration, 0.5 mg/mL) is added, and the plate are incubated at 37 ℃ for 4 h. Than solubilized overnight at 37 ℃ in a solution containing 10% SDS in 0.01 M HCL. The absorbance of each well is measured in a microplate reader at 570 nm.(Only for Reference)