The PI3K/mTOR pathway plays an important role in regulating cancer cell proliferation, growth, survival and metabolism. Activation of the PI3K/mTOR pathway by multiple mechanisms is one of the most frequently observed defects in human malignancies. The objective of these studies was to identify a small molecule that has anti-angiogenic activity in addition to PI3K and mTOR activity. P7170, a novel small molecule, inhibits PI3Kα and mTOR enzyme activity with IC50 value of 2.2 nM and 4.4 nM respectively. P7170 also inhibits a number of PI3Kα mutants. The Inhibition of PI3K-mTOR pathway in different cancer cell lines was demonstrated by 80 to 100% inhibition of the expression of phosphorylated AKT (pAKT), S6 ribosomal protein (pS6), and 4EBP1 (p4EBP1) upon treatment with P7170 in a western blot assay. P7170 also inhibited ALK1, an important enzyme involved in angiogenesis, and DNA-PK, an enzyme involved in DNA repair with the IC50 values of 47 and 1.5 nM, respectively. P7170 exhibited potent cytotoxic activity with IC50 values ranging from 2 to 22 nM in a number of cancer cell lines eg. ovarian (A2780), prostate (PC3), triple negative breast (MDA-MB-231 and MDA-MB-468), ER positive breast (MCF7), hepatocellular (HuH-7), renal (786-O), pancreatic (Panc1, AsPC1, and BxPC3), and colon (HCT116, HCT115, SW480) cancer cell lines. More interestingly, P7170 inhibited pAKT and pS6 in stem-like cells isolated from tumor samples of colon, breast, and head and neck cancer patients. P7170 also inhibited anchorage independent colony formation of tumor cells isolated from 39 different human tumor xenografts derived from tumors of patients with different cancers. In addition, P7170 inhibited angiogenesis in vitro in a tube formation assay, and in a matrigel plug assay in animals. It also inhibited metastasis of breast cancer cells. P7170 demonstrated significant in vivo efficacy when administered orally in three human xenograft tumor models. Tumor growth inhibition of 79% at 15 mg/kg in prostate (PC3), 78% at 10 mg/kg in ovarian (A2780), and 64% at 10 mg/kg in triple negative breast (MDA-MB-231) xenografts. Conclusion: P7170 has a unique profile of PI3K-mTOR pathway inhibition along with anti-angiogenic and anti- DNA repair activities. Combined with its effect on stem-like cells, P7170 may prove to be an effective anti-cancer drug.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3742. doi:1538-7445.AM2012-3742