Publications by authors named "Amanda J Emmons"

6 Publications

  • Page 1 of 1

Fragment-Based Discovery of Low-Micromolar ATAD2 Bromodomain Inhibitors.

J Med Chem 2015 Jul 9;58(14):5649-73. Epub 2015 Jul 9.

∥Drug Metabolism and Pharmacokinetics (DMPK), GlaxoSmithKline, Park Road, Ware, Hertfordshire SG12 0DP, United Kingdom.

Overexpression of ATAD2 (ATPase family, AAA domain containing 2) has been linked to disease severity and progression in a wide range of cancers, and is implicated in the regulation of several drivers of cancer growth. Little is known of the dependence of these effects upon the ATAD2 bromodomain, which has been categorized as among the least tractable of its class. The absence of any potent, selective inhibitors limits clear understanding of the therapeutic potential of the bromodomain. Here, we describe the discovery of a hit from a fragment-based targeted array. Optimization of this produced the first known micromolar inhibitors of the ATAD2 bromodomain.
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http://dx.doi.org/10.1021/acs.jmedchem.5b00772DOI Listing
July 2015

In vitro pharmacological characterization of vilanterol, a novel long-acting β2-adrenoceptor agonist with 24-hour duration of action.

J Pharmacol Exp Ther 2013 Jan 6;344(1):218-30. Epub 2012 Nov 6.

Respiratory TAU, GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK.

Vilanterol trifenatate (vilanterol) is a novel, long-acting β(2)-adrenoceptor (β(2)-AR) agonist with 24 h activity. In this study, we describe the preclinical pharmacological profile of vilanterol using radioligand binding and cAMP studies in recombinant assays as well as human and guinea pig tissue systems to characterize β(2)-AR binding and functional properties. Vilanterol displayed a subnanomolar affinity for the β(2)-AR that was comparable with that of salmeterol but higher than olodaterol, formoterol, and indacaterol. In cAMP functional activity studies, vilanterol demonstrated similar selectivity as salmeterol for β(2)- over β(1)-AR and β(3)-AR, but a significantly improved selectivity profile than formoterol and indacaterol. Vilanterol also showed a level of intrinsic efficacy that was comparable to indacaterol but significantly greater than that of salmeterol. In cellular cAMP production and tissue-based studies measuring persistence and reassertion, vilanterol had a persistence of action comparable with indacaterol and longer than formoterol. In addition, vilanterol demonstrated reassertion activity in both cell and tissue systems that was comparable with salmeterol and indacaterol but longer than formoterol. In human airways, vilanterol was shown to have a faster onset and longer duration of action than salmeterol, exhibiting a significant level of bronchodilation 22 h after treatment. From these investigations, the data for vilanterol are consistent, showing that it is a novel, potent, and selective β(2)-AR receptor agonist with a long duration of action. This pharmacological profile combined with clinical data is consistent with once a day dosing of vilanterol in the treatment of both asthma and chronic obstructive pulmonary disease (COPD).
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http://dx.doi.org/10.1124/jpet.112.198481DOI Listing
January 2013

Metabolism and disposition of vilanterol, a long-acting β(2)-adrenoceptor agonist for inhalation use in humans.

Drug Metab Dispos 2013 Jan 4;41(1):89-100. Epub 2012 Oct 4.

Division of Drug Metabolism and Pharmacokinetics, GlaxoSmithKline R&D, Park Road, Ware, Hertfordshire, SG12 0DP, United Kingdom.

The metabolism and disposition of vilanterol, a novel long-acting β(2)-adrenoceptor agonist (LABA) for inhalation use, was investigated after oral administration in humans. Single oral administrations of up to 500 μg of vilanterol were shown to be safe and well tolerated in two clinical studies in healthy men. In a human radiolabel study, six healthy men received a single oral dose of 200 μg of [(14)C]vilanterol (74 kBq). Plasma, urine, and feces were collected up to 168 hours after the dose and were analyzed for vilanterol, metabolites, and radioactivity. At least 50% of the radioactive dose was orally absorbed. The primary route of excretion of drug-related material was via O-dealkylation to metabolites, which were mainly excreted in urine. Vilanterol represented a very small percentage (<0.5%) of the total drug-related material in plasma, indicative of extensive first-pass metabolism. Circulating metabolites resulted mainly from O-dealkylation and exhibited negligible pharmacologic activity. The therapeutic dose level for vilanterol is 25 μg by the inhalation route. At this low-dose level, the likelihood of pharmacologically inactive metabolites causing unexpected toxicity is negligible. In addition to providing an assessment of the disposition of vilanterol in human, this work highlights a number of complexities associated with determining human absorption, distribution, metabolism, and excretion (ADME) for inhaled molecules--mainly related to the low chemical doses and complications associated with the inhalation route of administration.
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http://dx.doi.org/10.1124/dmd.112.048603DOI Listing
January 2013

Discovery and optimization of highly ligand-efficient oxytocin receptor antagonists using structure-based drug design.

Bioorg Med Chem Lett 2009 Feb 24;19(3):990-4. Epub 2008 Nov 24.

GlaxoSmithKline Pharmaceuticals, New Frontiers Science Park (North), Coldharbour Road, Harlow, Essex CM19 5AD, England, United Kingdom.

A novel oxytocin antagonist was identified by 'scaffold-hopping' using Cresset FieldScreen molecular field similarity searching. A single cycle of optimization driven by an understanding of the key pharmacophoric elements required for activity led to the discovery of a potent, selective and highly ligand-efficient oxytocin receptor antagonist. Selectivity over vasopressin receptors was rationalized based on differences in the structure of the natural ligands.
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http://dx.doi.org/10.1016/j.bmcl.2008.11.064DOI Listing
February 2009

Discovery and optimisation of a potent and selective tertiary sulfonamide oxytocin antagonist.

Bioorg Med Chem Lett 2009 Jan 12;19(2):528-32. Epub 2008 Nov 12.

GlaxoSmithKline Pharmaceuticals, New Frontiers Science Park (North), Coldharbour Road, Harlow, Essex CM19 5AD, England, UK.

The optimisation of a tertiary sulfonamide high-throughput screening hit is described. A combination of high-throughput chemistry, pharmacophore analysis and in silico PK profiling resulted in the discovery of potent sulfonamide oxytocin receptor antagonists with oral exposure and good selectivity over vasopressin receptors.
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http://dx.doi.org/10.1016/j.bmcl.2008.11.018DOI Listing
January 2009

Development of an insect-cell-based assay for detection of kinase inhibition using NF-kappaB-inducing kinase as a paradigm.

Biochem J 2009 Apr;419(1):65-73

Biological Reagents & Assay Development, GlaxoSmithKline R&D, New Frontiers Science Park, Third Avenue, Harlow, Essex, CM19 5AW, UK.

Identification of small-molecule inhibitors by high-throughput screening necessitates the development of robust, reproducible and cost-effective assays. The assay approach adopted may utilize isolated proteins or whole cells containing the target of interest. To enable protein-based assays, the baculovirus expression system is commonly used for generation and isolation of recombinant proteins. We have applied the baculovirus system into a cell-based assay format using NIK [NF-kappaB (nuclear factor kappaB)-inducing kinase] as a paradigm. We illustrate the use of the insect-cell-based assay in monitoring the activity of NIK against its physiological downstream substrate IkappaB (inhibitor of NF-kappaB) kinase-1. The assay was robust, yielding a signal/background ratio of 2:1 and an average Z' value of >0.65 when used to screen a focused compound set. Using secondary assays to validate a selection of the hits, we identified a compound that (i) was non-cytotoxic, (ii) interacted directly with NIK, and (iii) inhibited lymphotoxin-induced NF-kappaB p52 translocation to the nucleus. The insect cell assay represents a novel approach to monitoring kinase inhibition, with major advantages over other cell-based systems including ease of use, amenability to scale-up, protein expression levels and the flexibility to express a number of proteins by infecting with numerous baculoviruses.
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http://dx.doi.org/10.1042/BJ20081646DOI Listing
April 2009