An orally bioavailable and ATP-competitive inhibitor of mTOR (IC50 = 9.9 nM); selective for mTOR over a panel of more than 140 kinases, including various PI3Ks (IC50s = >3,000 nM); inhibits mTORC1 and mTORC2 in vitro (IC50s = 8 and 166 nM, respectively); induces cytotoxicity in MG-63, U2OS, and Saos-2 osteosarcoma and 786-0 kidney cancer cells and increases apoptosis in 786-0 and MG-63 cells; induces cell cycle arrest at the G1 phase and increases autophagy in MG-63 cells; reduces tumor growth in an MCF-7 breast cancer mouse xenograft model at 50 and 100 mg/kg; inhibits phosphorylation of mTORC1 and mTORC2 substrates p70S6K, S6, 4E-BP1, and Akt in MCF-7 and PC-3 xenograft tumors at 100 mg/kg; reduces tumor growth in U2OS and 786-0 mouse xenograft models at 20 mg/kg