WYE-687 is a potent ATP-competitive mTOR inhibitor with an IC50 of 7 nM. It is well reported that the mammalian target WYE-687 is a potent ATP-competitive mTOR inhibitor with an IC50 of 7 nM. It is well reported that the mammalian target of rapamycin (mTOR) is centrally involved in cell growth, metabolism, and angiogenesis. Significantly, the pyrazolopyrimidines were selective for mTOR over PI3Kα (>100-fold) and PI3Kγ (>500-fold) and were poorly active in a panel of 24 protein kinases. Unlike the rapalogs, WYE-687 acutely blocked mTORC2-dependent phosphorylation of AKT in vitro and in vivo. In various cancer cells, WYE-687 inhibited the mTORC1 substrate P-S6K(T389) and mTORC2 substrate P-AKT(S473) at submicromolar concentrations without significant inhibition of P-AKT(T308). WYE-687 was identified as an ATP-competitive, and selective inhibitor of mTOR kinase activity.