Susan M. Turci

Discovery of Novel, Induced-Pocket Binding Oxazolidinones as Potent, Selective, and Orally Bioavailable Tankyrase Inhibitors

Tankyrase (TNKS) is a poly-ADP-ribosylating protein (PARP) whose activity suppresses cellular axin protein levels and elevates β-catenin concentrations, resulting in increased oncogene expression. The inhibition of tankyrase (TNKS1 and 2) may reduce the levels of β-catenin-mediated transcription and inhibit tumorigenesis. Compound 1 is a previously described moderately potent tankyrase inhibitor that suffers from poor pharmacokinetic properties. Herein, we describe the utilization of structure-based design and molecular modeling toward novel, potent, and selective tankyrase inhibitors with improved pharmacokinetic properties (39, 40).

Structure-Guided Design of Aminopyrimidine Amides as Potent, Selective Inhibitors of Lymphocyte Specific Kinase: Synthesis, Structure–Activity Relationships, and Inhibition of in Vivo T Cell Activation

The lymphocyte-specific kinase (Lck), a member of the Src family of cytoplasmic tyrosine kinases, is expressed in T cells and natural killer (NK) cells. Genetic evidence, including knockout mice and human mutations, demonstrates that Lck kinase activity is critical for normal T cell development, activation, and signaling. Selective inhibition of Lck is expected to offer a new therapy for the treatment of T-cell-mediated autoimmune and inflammatory disease. With the aid of X-ray structure-based analysis, aminopyrimidine amides 2 and 3 were designed from aminoquinazolines 1, which had previously been demonstrated to exhibit potent inhibition of Lck and T cell proliferation. In this report, we describe the synthesis and structure-activity relationships of a series of novel aminopyrimidine amides 3 possessing improved cellular potency and selectivity profiles relative to their aminoquinazoline predecessors 1. Orally bioavailable compound 13b inhibited the anti-CD3-induced production of interleukin-2 (IL-2) in mice in a dose-dependent manner (ED 50 = 9.4 mg/kg).

Development of Novel Dual Binders as Potent, Selective, and Orally Bioavailable Tankyrase Inhibitors

Tankyrases (TNKS1 and TNKS2) are proteins in the poly ADP-ribose polymerase (PARP) family. They have been shown to directly bind to axin proteins, which negatively regulate the Wnt pathway by promoting β-catenin degradation. Inhibition of tankyrases may offer a novel approach to the treatment of APC-mutant colorectal cancer. Hit compound 8 was identified as an inhibitor of tankyrases through a combination of substructure searching of the Amgen compound collection based on a minimal binding pharmacophore hypothesis and high-throughput screening. Herein we report the structure- and property-based optimization of compound 8 leading to the identification of more potent and selective tankyrase inhibitors 22 and 49 with improved pharmacokinetic properties in rodents, which are well suited as tool compounds for further in vivo validation studies.

Discovery of 2,4-bis-arylamino-1,3-pyrimidines as insulin-like growth factor-1 receptor (IGF-1R) inhibitors

The insulin-like growth factor-1 receptor (IGF-1R) plays an important role in the regulation of cell growth and differentiation, and in protection from apoptosis. IGF-1R has been shown to be an appealing target for the treatment of human cancer. Herein, we report the synthesis, structure-activity relationships (SAR), X-ray cocrystal structure and in vivo tumor study results for a series of 2,4-bis-arylamino-1,3-pyrimidines.

2-Phenylamino-6-cyano-1H-benzimidazole-based isoform selective casein kinase 1 gamma (CK1γ) inhibitors

Screening of the Amgen compound library led to the identification of 2-phenylamino-6-cyano-1H-benzimidazole 1a as a potent CK1 gamma inhibitor with excellent kinase selectivity and unprecedented CK1 isoform selectivity. Further structure-based optimization of this series resulted in the discovery of 1h which possessed good enzymatic and cellular potency, excellent CK1 isoform and kinase selectivity, and acceptable pharmacokinetic properties.

Structure-Based Design of Potent and Selective CK1γ Inhibitors.

Aberrant activation of the Wnt pathway is believed to drive the development and growth of some cancers. The central role of CK1γ in Wnt signal transduction makes it an attractive target for the treatment of Wnt-pathway dependent cancers. We describe a structure-based approach that led to the discovery of a series of pyridyl pyrrolopyridinones as potent and selective CK1γ inhibitors. These compounds exhibited good enzyme and cell potency, as well as selectivity against other CK1 isoforms. A single oral dose of compound 13 resulted in significant inhibition of LRP6 phosphorylation in a mouse tumor PD model.

Abstract B45: Epigenetic signature of human breast cancer subtypes

Gene expression profiling has been used to extend classification of human breast cancers into five main sub‐types having distinct clinical outcomes. The established prognostic markers ER, PR and HER‐2 remain prominent components of this refined scheme that delineates luminal (luminal A, luminal B and HER‐2) from non‐luminal (basal/BRCA1 mutant and normal‐like) breast cancers. Gene expression combined with immunohistochemical localization of various tumor markers in the normal mammary gland support the hypothesis that luminal and non‐luminal breast tumors originate from different cell types. In the current study we explore epigenetic determinants of the different breast cancer sub‐types using the genome‐wide DNA methylation patterns (Illumina Infinium) of fifty human breast cancer cell lines. Principal component analysis of baseline gene expression profiles (Agilent) showed a clear separation between the luminal and non‐luminal sub‐types in agreement with previously published studies using a largely overlapping panel of breast cell lines. Comparative marker selection analysis using the GenePattern analysis package was then performed independently on the DNA methylation and gene expression datasets. When the results of these two analyses were compared, a statistically significant reciprocal overlap of the selected markers was observed. These results strongly suggest that a large fraction of the most robust luminal gene expression classifiers are silenced by promoter methylation in non‐luminal cells, and conversely that many of the best non‐luminal classifiers are silenced in luminal cells. The classifier genes indentified in the breast cancer cell line panel include the most highly referenced luminal (KRT8, ESR1, AR, TFF1, TFF3, TOB1 and XBP‐1) and non‐luminal markers (DSC3, VIM, SFRP1, KRT5, KRT16, KRT17, and RUNX3 that have been used to classify primary breast cancers. These striking differences in DNA methylation patterns strengthen the hypotheses that luminal and non‐luminal sub‐types arise from different precursor cells and that their transcriptional programs may be largely established during the process of cell specification in the mammary epithelial bi‐layer. Since CpG island methylation is stable and robustly preserved in archival tissues, it is likely that a methylation signature comprised of a few key genes could be used to, for example, identify poor‐prognosis, basal‐type breast cancers. It is also possible that such a test would be more quantitative, accurate and reproducible than the “triple‐negative” diagnosis currently based on the absence of immumohistochemical staining for ER, PR and HER‐2. Citation Information: Cancer Res 2009;69(23 Suppl):B45.