316 research outputs found

    Multi-Objective Big Data Optimization with jMetal and Spark

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    Big Data Optimization is the term used to refer to optimization problems which have to manage very large amounts of data. In this paper, we focus on the parallelization of metaheuristics with the Apache Spark cluster computing system for solving multi-objective Big Data Optimization problems. Our purpose is to study the influence of accessing data stored in the Hadoop File System (HDFS) in each evaluation step of a metaheuristic and to provide a software tool to solve these kinds of problems. This tool combines the jMetal multi-objective optimization framework with Apache Spark. We have carried out experiments to measure the performance of the proposed parallel infrastructure in an environment based on virtual machines in a local cluster comprising up to 100 cores. We obtained interesting results for computational e ort and propose guidelines to face multi-objective Big Data Optimization problems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    G-quadruplex DNA structures in human stem cells and differentiation.

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    Funder: Herchel Smith FundsThe establishment of cell identity during embryonic development involves the activation of specific gene expression programmes and is underpinned by epigenetic factors including DNA methylation and histone post-translational modifications. G-quadruplexes are four-stranded DNA secondary structures (G4s) that have been implicated in transcriptional regulation and cancer. Here, we show that G4s are key genomic structural features linked to cellular differentiation. We find that G4s are highly abundant in human embryonic stem cells and are lost during lineage specification. G4s are prevalent in enhancers and promoters. G4s that are found in common between embryonic and downstream lineages are tightly linked to transcriptional stabilisation of genes involved in essential cellular functions as well as transitions in the histone post-translational modification landscape. Furthermore, the application of small molecules that stabilise G4s causes a delay in stem cell differentiation, keeping cells in a more pluripotent-like state. Collectively, our data highlight G4s as important epigenetic features that are coupled to stem cell pluripotency and differentiation

    Distinct Mechanisms for Induction and Tolerance Regulate the Immediate Early Genes Encoding Interleukin 1β and Tumor Necrosis Factor α

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    Interleukin-1β and Tumor Necrosis Factor α play related, but distinct, roles in immunity and disease. Our study revealed major mechanistic distinctions in the Toll-like receptor (TLR) signaling-dependent induction for the rapidly expressed genes (IL1B and TNF) coding for these two cytokines. Prior to induction, TNF exhibited pre-bound TATA Binding Protein (TBP) and paused RNA Polymerase II (Pol II), hallmarks of poised immediate-early (IE) genes. In contrast, unstimulated IL1B displayed very low levels of both TBP and paused Pol II, requiring the lineage-specific Spi-1/PU.1 (Spi1) transcription factor as an anchor for induction-dependent interaction with two TLR-activated transcription factors, C/EBPβ and NF-κB. Activation and DNA binding of these two pre-expressed factors resulted in de novo recruitment of TBP and Pol II to IL1B in concert with a permissive state for elongation mediated by the recruitment of elongation factor P-TEFb. This Spi1-dependent mechanism for IL1B transcription, which is unique for a rapidly-induced/poised IE gene, was more dependent upon P-TEFb than was the case for the TNF gene. Furthermore, the dependence on phosphoinositide 3-kinase for P-TEFb recruitment to IL1B paralleled a greater sensitivity to the metabolic state of the cell and a lower sensitivity to the phenomenon of endotoxin tolerance than was evident for TNF. Such differences in induction mechanisms argue against the prevailing paradigm that all IE genes possess paused Pol II and may further delineate the specific roles played by each of these rapidly expressed immune modulators. © 2013 Adamik et al

    Androgen receptor phosphorylation at serine 515 by Cdk1 predicts biochemical relapse in prostate cancer patients

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    <br>Background:Prostate cancer cell growth is dependent upon androgen receptor (AR) activation, which is regulated by specific kinases. The aim of the current study is to establish if AR phosphorylation by Cdk1 or ERK1/2 is of prognostic significance.</br> <br>Methods: Scansite 2.0 was utilised to predict which AR sites are phosphorylated by Cdk1 and ERK1/2. Immunohistochemistry for these sites was then performed on 90 hormone-naive prostate cancer specimens. The interaction between Cdk1/ERK1/2 and AR phosphorylation was investigated in vitro using LNCaP cells.</br><br>Results:Phosphorylation of AR at serine 515 (pAR(S515)) and PSA at diagnosis were independently associated with decreased time to biochemical relapse. Cdk1 and pCdk1(161), but not ERK1/2, correlated with pAR(S515). High expression of pAR(S515) in patients with a PSA at diagnosis of ≤20 ng ml(-1) was associated with shorter time to biochemical relapse (P=0.019). This translated into a reduction in disease-specific survival (10-year survival, 38.1% vs 100%, P<0.001). In vitro studies demonstrated that treatment with Roscovitine (a Cdk inhibitor) caused a reduction in pCdk1(161) expression, pAR(S515)expression and cellular proliferation.</br> <br>Conclusion: In prostate cancer patients with PSA at diagnosis of ≤20 ng ml(-1), phosphorylation of AR at serine 515 by Cdk1 may be an independent prognostic marker.</br&gt

    Short communication: Glutamine modulates inflammatory responses to lipopolysaccharide in ex vivo bovine endometrium

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    Bacteria infect the endometrium lining the uterus of cattle after parturition, and clearance of these microbes depends on a robust innate immune response to bacterial molecules, such as the endotoxin lipopolysaccharide (LPS). Endometrial inflammation is characterized by secretion of the cytokines IL-1β and IL-6 and the chemokine IL-8. However, animals often fail to clear invading bacteria and develop uterine disease if they are in negative energy balance, with reduced abundance of glucose and glutamine, which are substrates for energy in tissues. Depletion of glucose blunts inflammatory responses in the endometrium, but the role of glutamine is not clear. The present study tested the hypothesis that depletion of glutamine compromises inflammatory responses to LPS in endometrial tissue. Ex vivo organ cultures of endometrium were challenged with LPS, and culture supernatants accumulated IL-1β, IL-6, and IL-8, as expected. However, reducing the availability of glutamine in culture medium containing glucose reduced the accumulation of IL-1β, IL-6, and IL-8 by >50%. Surprisingly, in the absence of glucose, supplying increasing amounts of glutamine was not sufficient to augment inflammatory responses to LPS, whereas, in the absence of glutamine, supplying more glucose increased inflammation. Furthermore, inhibiting glycolysis reduced the accumulation of IL-1β, IL-6, and IL-8 by >50%, even when glutamine and glucose were abundant. In conclusion, depletion of glutamine reduces inflammatory responses to LPS in the endometrium, and the activity of glutamine depends on glucose and glycolysis. These data provide mechanistic insights into how negative energy balance may be linked to postpartum uterine disease

    Landscape of G-quadruplex DNA structural regions in breast cancer.

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    Response and resistance to anticancer therapies vary due to intertumor and intratumor heterogeneity1. Here, we map differentially enriched G-quadruplex (G4) DNA structure-forming regions (∆G4Rs) in 22 breast cancer patient-derived tumor xenograft (PDTX) models. ∆G4Rs are associated with the promoters of highly amplified genes showing high expression, and with somatic single-nucleotide variants. Differences in ΔG4R landscapes reveal seven transcription factor programs across PDTXs. ∆G4R abundance and locations stratify PDTXs into at least three G4-based subtypes. ∆G4Rs in most PDTXs (14 of 22) were found to associate with more than one breast cancer subtype, which we also call an integrative cluster (IC)2. This suggests the frequent coexistence of multiple breast cancer states within a PDTX model, the majority of which display aggressive triple-negative IC10 gene activity. Short-term cultures of PDTX models with increased ∆G4R levels are more sensitive to small molecules targeting G4 DNA. Thus, G4 landscapes reveal additional IC-related intratumor heterogeneity in PDTX biopsies, improving breast cancer stratification and potentially identifying new treatment strategies.The Caldas and Balasubramanian laboratories are supported by core funding from Cancer Research UK (C14303/A17197). The Balasubramanian laboratory is supported by Program grant funding from Cancer Research UK (C9681/A18618 and C9681/A29214) and a Wellcome Trust Investigator Award (209441/z/17/z). Prior to the revision of this study work by Dr. Robert Hänsel-Hertsch was supported by the Balasubramanian group, afterwards additionally supported by core funding of the Center for Molecular Medicine Cologne (CMMC)

    TIGIT can inhibit T cell activation via ligation-induced nanoclusters, independent of CD226 co-stimulation

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    TIGIT is an inhibitory receptor expressed on lymphocytes and can inhibit T cells by preventing CD226 co-stimulation through interactions in cis or through competition of shared ligands. Whether TIGIT directly delivers cell-intrinsic inhibitory signals in T cells remains unclear. Here we show, by analysing lymphocytes from matched human tumour and peripheral blood samples, that TIGIT and CD226 co-expression is rare on tumour-infiltrating lymphocytes. Using super-resolution microscopy and other techniques, we demonstrate that ligation with CD155 causes TIGIT to reorganise into dense nanoclusters, which coalesce with T cell receptor (TCR)-rich clusters at immune synapses. Functionally, this reduces cytokine secretion in a manner dependent on TIGIT’s intracellular ITT-like signalling motif. Thus, we provide evidence that TIGIT directly inhibits lymphocyte activation, acting independently of CD226, requiring intracellular signalling that is proximal to the TCR. Within the subset of tumours where TIGIT-expressing cells do not commonly co-express CD226, this will likely be the dominant mechanism of action

    Targeting multiple effector pathways in pancreatic ductal adenocarcinoma with a g-quadruplex-binding small molecule

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    Human pancreatic ductal adenocarcinoma (PDAC) involves the dysregulation of multiple signaling pathways. A novel approach to the treatment of PDAC is described, involving the targeting of cancer genes in PDAC pathways having over-representation of G-quadruplexes, using the trisubstituted naphthalene diimide quadruplex-binding compound 2,7-bis(3-morpholinopropyl)-4-((2-(pyrrolidin-1-yl)ethyl)amino)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (CM03). This compound has been designed by computer modeling, is a potent inhibitor of cell growth in PDAC cell lines, and has anticancer activity in PDAC models, with a superior profile compared to gemcitabine, a commonly used therapy. Whole-transcriptome RNA-seq methodology has been used to analyze the effects of this quadruplex-binding small molecule on global gene expression. This has revealed the down-regulation of a large number of genes, rich in putative quadruplex elements and involved in essential pathways of PDAC survival, metastasis, and drug resistance. The changes produced by CM03 represent a global response to the complexity of human PDAC and may be applicable to other currently hard-to-treat cancers

    Experiences Marketing: A Cultural Philosophy for Contemporary Hospitality Marketing Studies

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    This article explores the landscape of contemporary hospitality marketing. It is argued that the teaching and academic discussions that surround the subject area adopt a predominantly positivistic approach; although important, that does not adequately reflect the nature of the industry or the products offered. Such a metrics-oriented position, although significant in the formulation of marketing strategy, does not reflect the complex experiential, nontangible nature of the hospitality product. This article presents a culturally located philosophy that reflects the multifaceted nature of the industry. The philosophy is underpinned by three precepts that draw from a multidisciplinary theoretical framework to create a more subject-specific approach to marketing, that when woven with traditional approaches can create a more effective and informed contemporary approach
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