P7170: A Novel Molecule with Unique Profile of mTORC1/C2 and Activin Receptor-like Kinase 1 Inhibition Leading to Antitumor and Antiangiogenic Activity.

The mTOR pathway is often upregulated in cancer and thus intensively pursued as a target to design novel anticancer therapies. Approved and emerging drugs targeting the mTOR pathway have positively affected the clinical landscape. Recently, activin receptor-like kinase 1 (ALK1), belonging to the TGFß receptor family, has been reported as an emerging target for antiangiogenic cancer therapy. Here, we describe a novel orally efficacious compound, P7170, that inhibits mTORC1/mTORC2/ALK1 activity with a potent cell growth inhibition. In cell-based assays, P7170 strongly inhibited (IC50 < 10 nmol/L) the phosphorylation of p70S6K (T389) and pAKT (S473). In many cancer cell lines, such as prostate, ovarian, colon, and renal, P7170 treatment resulted in marked cell growth inhibition. Furthermore, it induced G1-S cell-cycle arrest and autophagy. In vitro HUVEC tube formation, in vivo Matrigel plug, and rat aorta ring assays demonstrated that P7170 exhibited significant antiangiogenic activity. In addition, ALK1 knockdown studies in HUVEC confirmed that the antiangiogenic activity of P7170 was primarily due to ALK1 inhibition. Strong inhibition of ALK1 in addition to mTORC1/mTORC2 differentiates P7170 in its mechanism of action in comparison with existing inhibitors. In vivo mouse xenograft studies revealed P7170 to exhibit a significant dose-dependent tumor growth inhibition in a broad range of human tumor types when administered orally at 10 to 20 mg/kg doses. The distinctive pharmacological profile with favorable pharmacokinetic parameters and in vivo efficacy makes P7170 an attractive candidate for clinical development. It is currently being tested in phase I clinical studies.

Discovery of P3971 an orally efficacious novel anticancer agent targeting HIF-1α and STAT3 pathways.

Hypoxia-inducible factor-1α (HIF-1α) and signal transducer and activator of transcription 3 (STAT3) are transcription factors and are activated in response to hypoxia. Both HIF-1α and STAT3 regulate various aspects of cancer biology such as cell survival, proliferation, angiogenesis etc. and are constitutively expressed in a wide range of human cancers. In the last decade, over expression of HIF-1α and STAT3 has been demonstrated in many common human cancers, thereby emerging as highly compelling anticancer targets for drug discovery. We herein report the design and synthesis of new imidazopyridine based potent dual inhibitors of HIF-1α and STAT3 pathways. The lead compound of this series P3971 has been identified as a potent inhibitor of HIF-1α (200 nM) and STAT3 (350 nM) with significant antiproliferative activity against various cancer cell lines. Moreover, P3971 was also found to be orally efficacious in HCT116 (colon cancer) and H460 (lung cancer) xenograft mice models.

Development of novel inhibitors targeting HIF-1α towards anticancer drug discovery.

Hypoxia-inducible factor-1α (HIF-1α) is a critical regulatory protein of cellular response to hypoxia, and regulates the transcription of many genes involved in key aspects of cancer biology, including immortalization, maintenance of stem cell pools, cellular dedifferentiation, vascularization, and invasion/metastasis. HIF-1α has been implicated in the regulation of genes involved in angiogenesis, for example, VEGF and is associated with tumor progression. In the last decade, over expression of HIF-1α has been demonstrated in many common human cancers and emerging as a validated target for anticancer drug discovery. Here we report the discovery of newly designed and synthesized pyridylpyrimidine based potent and selective inhibitors of HIF-1α. P2630 has been found as potent antiproliferative, antiangiogenic and orally efficacious compound in PC-3 xenograft mice model.

Synthesis and therapeutic evaluation of pyridyl based novel mTOR inhibitors.

A series of novel cyanopyridyl based molecules (1-14) were designed, synthesized and probed for inhibition of mammalian target of rapamycin (mTOR) activity. Compound 14 was found to be a potent inhibitor of mTOR activity as assessed by enzyme-linked immunoassays and Western blot analysis. Most importantly, systemic application (intraperitoneal; ip) of compound 14 significantly suppressed macroscopic and histological abnormalities associated with chemically-induced murine colitis.

A novel mTOR inhibitor is efficacious in a murine model of colitis.

Ulcerative colitis is an autoimmune-inflammatory disease characterized by increased proliferation of colonic epithelial cells, dysregulation of signal transduction pathways, elevated mucosal T cell activation, increased production of proinflammatory cytokines, and enhanced leukocyte infiltration into colonic interstitium. Several compounds that possess antiproliferative properties and/or inhibit cytokine production exhibit a therapeutic effect in murine models of colitis. Mammalian target of rapamycin (mTOR), a protein kinase regulating cell proliferation, is implicated in colon carcinogenesis. In this study, we report that a novel haloacyl aminopyridine-based molecule (P2281) is a mTOR inhibitor and is efficacious in a murine model of human colitis. In vitro studies using Western blot analysis and cell-based ELISA assays showed that P2281 inhibits mTOR activity in colon cancer cells. In vitro and in vivo assays of proinflammatory cytokine production revealed that P2281 diminishes induced IFN-gamma production but not TNF-alpha production, indicating preferential inhibitory effects of P2281 on T cell function. In the dextran sulfate sodium (DSS) model of colitis, 1) macroscopic colon observations demonstrated that P2281 significantly inhibited DSS-induced weight loss, improved rectal bleeding index, decreased disease activity index, and reversed DSS-induced shortening of the colon; 2) histological analyses of colonic tissues revealed that P2281 distinctly attenuated DSS-induced edema, prominently diminished the leukocyte infiltration in the colonic mucosa, and resulted in protection against DSS-induced crypt damage; and 3) Western blot analysis showed that P2281 blocks DSS-induced activation of mTOR. Collectively, these results provide direct evidence that P2281, a novel mTOR inhibitor, suppresses DSS-induced colitis by inhibiting T cell function and is a potential therapeutic for colitis. Given that compounds with anticancer activity show promising anti-inflammatory efficacy, our findings reinforce the cross-therapeutic functionality of potential drugs.

Design and synthesis of novel furoquinoline based inhibitors of multiple targets in the PI3K/Akt-mTOR pathway.

We herein report the design and synthesis of furoquinoline based novel molecules (16-36) and their in vitro multiple targeted inhibitory potency against PI3K/Akt phosphorylation and mTOR using cell based and cell-free kinase assay. In particular, compound 23 in addition to PI3K-mTOR inhibitory potency, it has shown potent inhibition of hypoxia-induced accumulation of HIF-1alpha protein in U251-HRE cell line. The inhibitory activities of compound 23 were confirmed by Western blot analysis, using human non-small cell lung carcinoma H-460 cell line and glioblastoma U251 cell lines.