Publications by authors named "Emilio Alvarez Ruiz"

7 Publications

  • Page 1 of 1

Development of a Novel High-Density [3H]Hypoxanthine Scintillation Proximity Assay To Assess Plasmodium falciparum Growth.

Antimicrob Agents Chemother 2016 10 23;60(10):5949-56. Epub 2016 Sep 23.

Platform Technology and Science, Centro de Investigación Básica, GlaxoSmithKline, Tres Cantos, Spain.

The discovery and development of new antimalarial drugs are becoming imperative because of the spread of resistance to current clinical treatments. The lack of robustly validated antimalarial targets and the difficulties with the building in of whole-cell activity in screening hits are hampering target-based approaches. However, phenotypic screens of structurally diverse molecule libraries are offering new opportunities for the identification of novel antimalarials. Several methodologies can be used to determine the whole-cell in vitro potencies of antimalarial hits. The [(3)H]hypoxanthine incorporation assay is considered the "gold standard" assay for measurement of the activity of antimalarial compounds against intraerythrocytic forms of Plasmodium falciparum However, the method has important limitations, as the assay is not amenable for high-throughput screening since it remains associated with the 96-well plate format. We have overcome this drawback by adapting the [(3)H]hypoxanthine incorporation method to a 384-well high-density format by coupling a homogeneous scintillation proximity assay (SPA) and thus eliminating the limiting filtration step. This SPA has been validated using a diverse set of 1,000 molecules, including both a representative set from the Tres Cantos Antimalarial Set (TCAMS) of compounds and molecules inactive against whole cells. The results were compared with those from the P. falciparum lactate dehydrogenase whole-cell assay, another method that is well established as a surrogate for parasite growth and is amenable for high-throughput screening. The results obtained demonstrate that the SPA-based [(3)H]hypoxanthine incorporation assay is a suitable design that is adaptable to high-throughput antimalarial drug screening and that maintains the features, robustness, and reliability of the standard filtration hypoxanthine incorporation method.
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http://dx.doi.org/10.1128/AAC.00433-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5038259PMC
October 2016

New direct inhibitors of InhA with antimycobacterial activity based on a tetrahydropyran scaffold.

Eur J Med Chem 2016 Apr 8;112:252-257. Epub 2016 Feb 8.

University of Ljubljana, Faculty of Pharmacy, Ljubljana, Slovenia. Electronic address:

Tetrahydropyran derivative 1 was discovered in a high-throughput screening campaign to find new inhibitors of mycobacterial InhA. Following initial in-vitro profiling, a structure-activity relationship study was initiated and a focused library of analogs was synthesized and evaluated. This yielded compound 42 with improved antimycobacterial activity and low cytotoxicity. Additionally, the crystal structure of InhA in complex with inhibitor 1 was resolved, to reveal the binding mode and provide hints for further optimization.
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http://dx.doi.org/10.1016/j.ejmech.2016.02.008DOI Listing
April 2016

Release of 50 new, drug-like compounds and their computational target predictions for open source anti-tubercular drug discovery.

PLoS One 2015 7;10(12):e0142293. Epub 2015 Dec 7.

Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, Madrid, Spain.

As a follow up to the antimycobacterial screening exercise and the release of GSK´s first Tres Cantos Antimycobacterial Set (TCAMS-TB), this paper presents the results of a second antitubercular screening effort of two hundred and fifty thousand compounds recently added to the GSK collection. The compounds were further prioritized based on not only antitubercular potency but also on physicochemical characteristics. The 50 most attractive compounds were then progressed for evaluation in three different predictive computational biology algorithms based on structural similarity or GSK historical biological assay data in order to determine their possible mechanisms of action. This effort has resulted in the identification of novel compounds and their hypothesized targets that will hopefully fuel future TB drug discovery and target validation programs alike.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142293PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671658PMC
June 2016

Mining Natural-Products Screening Data for Target-Class Chemical Motifs.

J Biomol Screen 2014 Jun 11;19(5):749-57. Epub 2014 Feb 11.

Molecular Discovery Research, GlaxoSmithKline R&D Pharmaceuticals, Tres Cantos, Spain.

In this article, we describe two complementary data-mining approaches used to characterize the GlaxoSmithKline (GSK) natural-products set (NPS) based on information from the high-throughput screening (HTS) databases. Both methods rely on the aggregation and analysis of a large set of single-shot screening data for a number of biological assays, with the goal to reveal natural-product chemical motifs. One of them is an established method based on the data-driven clustering of compounds using a wide range of descriptors,(1)whereas the other method partitions and hierarchically clusters the data to identify chemical cores.(2,3)Both methods successfully find structural scaffolds that significantly hit different groups of discrete drug targets, compared with their relative frequency of demonstrating inhibitory activity in a large number of screens. We describe how these methods can be applied to unveil hidden information in large single-shot HTS data sets. Applied prospectively, this type of information could contribute to the design of new chemical templates for drug-target classes and guide synthetic efforts for lead optimization of tractable hits that are based on natural-product chemical motifs. Relevant findings for 7TM receptors (7TMRs), ion channels, class-7 transferases (protein kinases), hydrolases, and oxidoreductases will be discussed.
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http://dx.doi.org/10.1177/1087057114521463DOI Listing
June 2014

Encoded library technology as a source of hits for the discovery and lead optimization of a potent and selective class of bactericidal direct inhibitors of Mycobacterium tuberculosis InhA.

J Med Chem 2014 Feb 5;57(4):1276-88. Epub 2014 Feb 5.

ELT Boston, Platform Technology & Science, GlaxoSmithKline , Waltham, Massachusetts 02451, United States.

Tuberculosis (TB) is one of the world's oldest and deadliest diseases, killing a person every 20 s. InhA, the enoyl-ACP reductase from Mycobacterium tuberculosis, is the target of the frontline antitubercular drug isoniazid (INH). Compounds that directly target InhA and do not require activation by mycobacterial catalase peroxidase KatG are promising candidates for treating infections caused by INH resistant strains. The application of the encoded library technology (ELT) to the discovery of direct InhA inhibitors yielded compound 7 endowed with good enzymatic potency but with low antitubercular potency. This work reports the hit identification, the selected strategy for potency optimization, the structure-activity relationships of a hundred analogues synthesized, and the results of the in vivo efficacy studies performed with the lead compound 65.
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http://dx.doi.org/10.1021/jm401326jDOI Listing
February 2014

Fueling open-source drug discovery: 177 small-molecule leads against tuberculosis.

ChemMedChem 2013 Feb 10;8(2):313-21. Epub 2013 Jan 10.

Tres Cantos Medicines Development Campus (TCMDC), GlaxoSmithKline (GSK), Severo Ochoa 2, Tres Cantos, Madrid, Spain.

With the aim of fuelling open-source, translational, early-stage drug discovery activities, the results of the recently completed antimycobacterial phenotypic screening campaign against Mycobacterium bovis BCG with hit confirmation in M. tuberculosis H37Rv were made publicly accessible. A set of 177 potent non-cytotoxic H37Rv hits was identified and will be made available to maximize the potential impact of the compounds toward a chemical genetics/proteomics exercise, while at the same time providing a plethora of potential starting points for new synthetic lead-generation activities. Two additional drug-discovery-relevant datasets are included: a) a drug-like property analysis reflecting the latest lead-like guidelines and b) an early lead-generation package of the most promising hits within the clusters identified.
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http://dx.doi.org/10.1002/cmdc.201200428DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3743164PMC
February 2013

Lead discovery for microsomal prostaglandin E synthase using a combination of high-throughput fluorescent-based assays and RapidFire mass spectrometry.

J Biomol Screen 2012 Jun 14;17(5):641-50. Epub 2012 Feb 14.

Department of Screening, GlaxoSmithKline, Stevenage, UK.

Microsomal prostaglandin E synthase-1 (mPGES-1) represents an attractive target for the treatment of rheumatoid arthritis and pain, being upregulated in response to inflammatory stimuli. Biochemical assays for prostaglandin E synthase activity are complicated by the instability of the substrate (PGH(2)) and the challenge of detection of the product (PGE(2)). A coupled fluorescent assay is described for mPGES-1 where PGH(2) is generated in situ using the action of cyclooxygenase 2 (Cox-2) on arachidonic acid. PGE(2) is detected by coupling through 15-prostaglandin dehydrogenase (15-PGDH) and diaphorase. The overall coupled reaction was miniaturized to 1536-well plates and validated for high-throughput screening. For compound progression, a novel high-throughput mass spectrometry assay was developed using the RapidFire platform. The assay employs the same in situ substrate generation step as the fluorescent assay, after which both PGE(2) and a reduced form of the unreacted substrate were detected by mass spectrometry. Pharmacology and assay quality were comparable between both assays, but the mass spectrometry assay was shown to be less susceptible to interference and false positives. Exploiting the throughput of the fluorescent assay and the label-free, direct detection of the RapidFire has proved to be a powerful lead discovery strategy for this challenging target.
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http://dx.doi.org/10.1177/1087057111435700DOI Listing
June 2012