Phosphatidylinositol 3-kinase (PI3K) catalyzes the phosphorylation of phosphatidylinositol at the 3 position to produce the second messengers phosphatidylinositol-3,4-bisphosphate (PtdIns-(3,4)-P2 and PtdIns-(3,4,5)-P3). Class 1 PI3Ks are composed of a p110 catalytic subunit, of which there are four isoforms (p110α, p110β, p110δ, and p100γ), and a p85 regulatory subunit. GSK2636771 is an orally bioavailable inhibitor of PI3K p110β. At 1-10 μM, it decreases cell viability and Akt phosphorylation in p100β-dependent PTEN-deficient PC-3 prostate and BT549 and HCC70 breast cancer cell lines.
