Phosphatidylinositol 3-kinase (PI3K) catalyzes the phosphorylation of the 3' hydroxyl position of PIs to produce PtdIns-(3,4)-P2 and PtdIns-(3,4,5)-P3, important second messengers that modulate the activity of downstream targets Akt and mTOR. Aberrant PI3K/Akt is associated with many human cancers. CAY10626 is a potent, dual PI3Kα/mTOR inhibitor with IC50 values of 0.9 and 0.6 nM for the two respective kinases. In a tumor cell growth inhibition assay, CAY10626 demonstrates IC50 values of <3 and 13 nM for MDA361 (breast) and PC3 (prostate) cancer cell lines, respectively. When administered at 25-50 mg/k to MD361 xenograft mice, phosphorylation of the downstream targets of PI3Kα and mTOR (Akt T308, Akt S473, and S6K) was suppressed, and significant tumor regression was observed.
