Discovery of Selective, Orally Bioavailable Pyrazolopyridine Inhibitors of Protein Kinase Cθ (PKCθ) That Ameliorate Symptoms of Experimental Autoimmune Encephalomyelitis.

PKCθ plays an important role in T cell biology and is a validated target for a number of disease states. A series of potent and selective PKCθ inhibitors were designed and synthesized starting from a HTS hit compound. Cell activity, while initially a challenge to achieve, was built into the series by transforming the nitrile unit of the scaffold into a primary amine, the latter predicted to form a new hydrogen bond to Asp508 near the entrance of the ATP binding site of PKCθ.

Rational Design of 5-(4-(Isopropylsulfonyl)phenyl)-3-(3-(4-((methylamino)methyl)phenyl)isoxazol-5-yl)pyrazin-2-amine (VX-970, M6620): Optimization of Intra- and Intermolecular Polar Interactions of a New Ataxia Telangiectasia Mutated and Rad3-Related (ATR) Kinase Inhibitor.

The DNA damage response (DDR) is a DNA damage surveillance and repair mechanism that can limit the effectiveness of radiotherapy and DNA-damaging chemotherapy, commonly used treatment modalities in cancer. Two related kinases, ataxia telangiectasia mutated (ATM) and ATM and Rad3-related kinase (ATR), work together as apical proteins in the DDR to maintain genome stability and cell survival in the face of potentially lethal forms of DNA damage. However, compromised ATM signaling is a common characteristic of tumor cells, which places greater reliance on ATR to mediate the DDR.

Comparison of the accuracy of experimental and predicted pKa values of basic and acidic compounds.

Purpose: Assessment of the accuracy of experimental and theoretical methods of pKa determination for acids and bases as separate classes.

Methods: Four literature pKa datasets were checked for errors and pKa values assigned unambiguously to a single acidic and/or basic ionisation centre. A new chemically diverse and drug-like dataset was compiled from high-throughput UV-vis spectrophotometry pKa data.

Kinetic and mechanistic characterisation of Choline Kinase-α.

Choline Kinase is a key component of the Kennedy pathway that converts choline into a number of structural and signalling lipids that are essential for cell growth and survival. One member of the family, Choline Kinase-α (ChoKα) is frequently up-regulated in human cancers, and expression of ChoKα is sufficient to transform cells. Consequently ChoKα has been studied as a potential target for therapeutic agents in cancer research.

Advances in the design of ITK inhibitors.

Introduction: ITK is a member of the Tec family of nonreceptor protein tyrosine kinases that plays a central role in T-cell signaling. Its inhibition is seen as an attractive approach to the treatment of immune-mediated disorders. Insight into the function of ITK has emerged from studies on ITK-deficient mice, which exhibit defects in T-cell receptor (TCR) signaling and immune responses to pathogens.

Structure-based optimization of aminopyridines as PKCθ inhibitors.

The identification of a novel series of PKCθ inhibitors and subsequent optimization using docking based on a crystal structure of PKCθ is described. SAR was rapidly generated around an amino pyridine-ketone hit; (6-aminopyridin-2-yl)(2-aminopyridin-3-yl)methanone 2 leading to compound 21 which significantly inhibits production of IL-2 in a mouse SEB-IL2 model.

A Role for Hydration in Interleukin-2 Inducible T Cell Kinase (Itk) Selectivity.

The selectivity profile of kinase inhibitors is commonly explained in terms of favourable or unfavourable interactions between the inhibitor and active site residues. In practice residue sequence differences have not always been sufficient to explain observed selectivity profiles. A series of interleukin-2 inducible T cell kinase (Itk, EC 2.

Discovery of potent and selective inhibitors of ataxia telangiectasia mutated and Rad3 related (ATR) protein kinase as potential anticancer agents.

DNA-damaging agents are among the most frequently used anticancer drugs. However, they provide only modest benefit in most cancers. This may be attributed to a genome maintenance network, the DNA damage response (DDR), that recognizes and repairs damaged DNA.

Discovery and structure-activity relationship of 3-aminopyrid-2-ones as potent and selective interleukin-2 inducible T-cell kinase (Itk) inhibitors.

Interleukin-2 inducible T-cell kinase (Itk) plays a role in T-cell functions, and its inhibition potentially represents an attractive intervention point to treat autoimmune and allergic diseases. Herein we describe the discovery of a series of potent and selective novel inhibitors of Itk. These inhibitors were identified by structure-based design, starting from a fragment generated de novo, the 3-aminopyrid-2-one motif.

The discovery of the potent aurora inhibitor MK-0457 (VX-680).

The identification of a novel series of Aurora kinase inhibitors and exploitation of their SAR is described. Replacement of the initial quinazoline core with a pyrimidine scaffold and modification of substituents led to a series of very potent inhibitors of cellular proliferation. MK-0457 (VX-680) has been assessed in Phase II clinical trials in patients with treatment-refractory chronic myelogenous leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) containing the T315I mutation.

Site-specific fucosylation of sialylated polylactosamines by alpha1,3/4-fucosyltransferases-V and -VI Is defined by amino acids near the N terminus of the catalytic domain.

Fucose transfer from GDP-fucose to GlcNAc residues of the sialylated polylactosamine acceptor NeuAcalpha2-3Galbeta1-4Glc-NAcbeta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glcbeta1-ceramide leads to two isomeric monofucosyl antigens, VIM2 and sialyl-Le(x). Human alpha1,3/4-fucosyltransferase (FucT)-V catalyzes primarily the synthesis of VIM2, whereas human FucT-VI catalyzes primarily the synthesis of sialyl-Le(x). Thus, these two enzymes have distinct "site-specific fucosylation" properties.

Site-directed mutagenesis of glutamate 317 of bovine alpha-1,3Galactosyltransferase and its effect on enzyme activity: implications for reaction mechanism.

Bovine alpha1,3galactosyltransferase (alpha1,3GalT) transfers galactose from UDP-alpha-galactose to terminal beta-linked galactosyl residues with retention of configuration of the incoming galactose residue. The epitope synthesized has been shown to be critical for xenotransplantation. According to a proposed double-displacement reaction mechanism, glutamate-317 (E317) is thought to be the catalytic nucleophile.

Water-soluble molecular capsules: self-assembly and binding properties.

The self-assembly and characterization of water-soluble calix[4]arene-based molecular capsules (12) is reported. The assemblies are the result of ionic interactions between negatively charged calix[4]arenes 1 a and 1 b, functionalized at the upper rim with amino acid moieties, and a positively charged tetraamidiniumcalix[4]arene 2. The formation of the molecular capsules is studied by (1)H NMR spectroscopy, ESI mass spectrometry (ESI-MS), and isothermal titration calorimetry (ITC).

Mutation of amino acids in the alpha 1,3-fucosyltransferase motif affects enzyme activity and Km for donor and acceptor substrates.

Alpha 1,3-fucosyltransferases (FucT) share a conserved amino acid sequence designated the alpha 1,3 FucT motif that has been proposed to be important for nucleotide sugar binding. To evaluate the importance of the amino acids in this motif, each of the alpha 1,3 FucT motif amino acids was replaced with alanine (alanine scanning mutagenesis) in human FucT VI, and the resulting mutant proteins were analyzed for enzyme activity and kinetically characterized in those cases in which the mutant protein had sufficient activity. Two of the mutant proteins were inactive, six had less than 1% of wild-type activity, and four had approximately 10-50% of wild-type enzyme activity.

Crystal structure of aurora-2, an oncogenic serine/threonine kinase.

Aurora-2 is a key member of a closely related subgroup of serine/threonine kinases that plays important roles in the completion of essential mitotic events. Aurora-2 is oncogenic and amplified in various human cancers and could be an important therapeutic target for inhibitory molecules that would disrupt the cell cycle and block proliferation. We report the first crystal structure of Aurora-2 kinase in complex with adenosine.