Joshua Ryan Clayton

Discovery of LY2457546: a multi-targeted anti-angiogenic kinase inhibitor with a novel spectrum of activity and exquisite potency in the acute myelogenous leukemia-Flt-3-internal tandem duplication mutant human tumor xenograft model

SummaryLY2457546 is a potent and orally bioavailable inhibitor of multiple receptor tyrosine kinases involved in angiogenic and tumorigenic signalling. In biochemical and cellular assays, LY2457546 demonstrates potent activity against targets that include VEGFR2 (KDR), PDGFRβ, FLT-3, Tie-2 and members of the Eph family of receptors. With activities against both Tie2 and Eph receptors, LY2457546 possesses an activity profile that distinguishes it from multikinase inhibitors. When compared head to head with sunitinib, LY2457546 was more potent for inhibition of endothelial tube formation in an in vitro angiogenesis co-culture model with an intermittent treatment design. In vivo, LY2457546 inhibited VEGF-driven autophosphorylation of lung KDR in the mouse and rat in a dose and concentration dependent manner. LY2457546 was well tolerated and exhibited efficacy in a 13762 syngeneic rat mammary tumor model in both once and twice daily continuous dosing schedules and in mouse human tumor xenograft models of lung, colon, and prostate origin. Additionally, LY2457546 caused complete regression of well-established tumors in an acute myelogenous leukemia (AML) FLT3-ITD mutant xenograft tumor model. The observed efficacy that was displayed by LY2457546 in the AML FLT3-ITD mutant tumor model was superior to sunitinib when both were evaluated using equivalent doses normalized to in vivo inhibition of pKDR in mouse lung. LY2457546 was well tolerated in non-clinical toxicology studies conducted in rats and dogs. The majority of the toxicities observed were similar to those observed with other multi-targeted anti-angiogenic kinase inhibitors (MAKs) and included bone marrow hypocellularity, hair and skin depigmentation, cartilage dysplasia and lymphoid organ degeneration and necrosis. Thus, the unique spectrum of target activity, potent in vivo anti-tumor efficacy in a variety of rodent and human solid tumor models, exquisite potency against a clinically relevant model of AML, and non-clinical safety profile justify the advancement of LY2457546 into clinical testing.

An improved method for direct conversion of heteroaryl-aldehydes to heteroaryl-acetonitriles

Abstract Treatment of heteroaryl-aldehydes with diethyl cyanophosphonate in the presence of a catalytic amount of LiCN affords phosphorylated cyanohydrins which are reduced in situ with SmI 2 to give heteroaryl-acetonitriles in generally good overall yields (50–100%). The generality of the process is demonstrated.

Design and synthesis of a novel series of [1-(4-hydroxy-benzyl)-1H-indol-5-yloxy]-acetic acid compounds as potent, selective, thyroid hormone receptor β agonists

The design, synthesis, and structure activity relationships for a novel series of indoles as potent, selective, thyroid hormone receptor β (TRβ) agonists is described. Compounds with >50× binding selectivity for TRβ over TRα were generated and evaluation of compound 1c from this series in a model of dyslipidemia demonstrated positive effects on plasma lipid endpoints in vivo.

Abstract 2820: LY2784544, a small molecule JAK2 inhibitor, induces apoptosis in inflammatory breast cancer spheres through targeting IL-6-JAK-STAT3 pathway

Inflammatory breast cancer (IBC) is more aggressive and deadly than other breast cancers (K Rowan. JNCI. 2009;101(19):1302-1304). IBC cells secrete angiogenic and vasculogenic growth factors, such as VEGF, bFGF, IL-6 and IL-8, resulting in a cluster of tumor cells, termed anembolus. Through maintaining cell-cell interactions, the IBC emboli can become resistant to “anoikis”, a cell death process following the loss of contact from their neighboring cells. It is hypothesized that this resistance may allow IBC cells to survive the migration through lymphatic vessels and facilitate development of skin and lymph node metastasis. With current therapy, the disease-free survival for IBC patients is only about 35% (SD Merajver et al. J Clin Oncol. 1997;15(8):2873-81). Clearly better therapy is needed for patients with IBC and insights may be gained from exploration of and subsequent interventions in the roles these growth factors play in the biology of IBC. In this study, we investigated the role of IL-6 in activating the signal transducer and activator of transcription 3 (STAT3), conferring resistance to anoikis, and promoting cell proliferation in IBC SUM-149 tumor spheres. Moreover, we targeted JAK2, a transducer of IL-6 signaling to STAT3, by a small molecule JAK2 inhibitor, LY2784544, to inhibit the IL-6-Stat3 pathway and induce apoptosis in SUM-149 tumor spheres. In brief, SUM-149 cells were grown to form tumor spheres under low adherence culture conditions. IL-6 mediated-Stat3 activation and the induction of the cleavage of PARP were evaluated by Western Blotting. Anoikis and cell viability were measured by calcein-AM accumulation and the expression of IL-6 was examined by RT-PCR. We found that exogenous IL-6 activated STAT3, conferred resistance to anoikis and promoted the cell proliferation in SUM-149 cells under the low adherent culture condition. Furthermore, the expression of IL-6 was increased by 50-fold in IBC tumor spheres as measured by RT-PCR. The autocrine production of IL-6 activated STAT3 and inhibited anoikis- induced apoptosis in SUM-149 tumor spheres. Very importantly, we showed that targeting JAK2 by LY2784544 potently inhibited the phosphorylation of STAT3 in a dose dependent manner with an IC50 of 0.25 µM. Blockage of this signal pathway by LY2784544 resulted in potent induction of apoptosis (EC50=0.49 µM). Taken together, these studies suggest the IL-6-JAK-STAT3 pathway may serve as a molecular signature of IBC and as a potential therapeutic target. LY2784544 is currently in clinical studies for the treatment of myeloid proliferative neoplasm indications and the results reported here support clinical investigation for the treatment of IBC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2820. doi:10.1158/1538-7445.AM2011-2820