224 research outputs found

    New Perspectives in Sinographic Language Processing Through the Use of Character Structure

    Full text link
    Chinese characters have a complex and hierarchical graphical structure carrying both semantic and phonetic information. We use this structure to enhance the text model and obtain better results in standard NLP operations. First of all, to tackle the problem of graphical variation we define allographic classes of characters. Next, the relation of inclusion of a subcharacter in a characters, provides us with a directed graph of allographic classes. We provide this graph with two weights: semanticity (semantic relation between subcharacter and character) and phoneticity (phonetic relation) and calculate "most semantic subcharacter paths" for each character. Finally, adding the information contained in these paths to unigrams we claim to increase the efficiency of text mining methods. We evaluate our method on a text classification task on two corpora (Chinese and Japanese) of a total of 18 million characters and get an improvement of 3% on an already high baseline of 89.6% precision, obtained by a linear SVM classifier. Other possible applications and perspectives of the system are discussed.Comment: 17 pages, 5 figures, presented at CICLing 201

    Ultrafast glutamate sensors resolve high-frequency release at Schaffer collateral synapses

    Get PDF
    Glutamatergic synapses display a rich repertoire of plasticity mechanisms on many different time scales, involving dynamic changes in the efficacy of transmitter release as well as changes in the number and function of postsynaptic glutamate receptors. The genetically encoded glutamate sensor iGluSnFR enables visualization of glutamate release from presynaptic terminals at frequencies up to ∼10 Hz. However, to resolve glutamate dynamics during high-frequency bursts, faster indicators are required. Here, we report the development of fast (iGluf) and ultrafast (iGluu) variants with comparable brightness but increased Kd for glutamate (137 μM and 600 μM, respectively). Compared with iGluSnFR, iGluu has a sixfold faster dissociation rate in vitro and fivefold faster kinetics in synapses. Fitting a three-state model to kinetic data, we identify the large conformational change after glutamate binding as the rate-limiting step. In rat hippocampal slice culture stimulated at 100 Hz, we find that iGluu is sufficiently fast to resolve individual glutamate release events, revealing that glutamate is rapidly cleared from the synaptic cleft. Depression of iGluu responses during 100-Hz trains correlates with depression of postsynaptic EPSPs, indicating that depression during high-frequency stimulation is purely presynaptic in origin. At individual boutons, the recovery from depression could be predicted from the amount of glutamate released on the second pulse (paired pulse facilitation/depression), demonstrating differential frequency-dependent filtering of spike trains at Schaffer collateral boutons

    RUNX3 transcript variants have distinct roles in ovarian carcinoma and differently influence platinum sensitivity and angiogenesis

    Get PDF
    The prognosis of late-stage epithelial ovarian cancer (EOC) patients is affected by chemotherapy response and the malignant potential of the tumor cells. In earlier work, we identified hypermethylation of the runt-related transcription factor 3 gene (RUNX3) as a prognostic biomarker and contrary functions of transcript variants (TV1 and TV2) in A2780 and SKOV3 cells. The aim of the study was to further validate these results and to increase the knowledge about RUNX3 function in EOC. New RUNX3 overexpression models of high-grade serous ovarian cancer (HGSOC) were established and analyzed for phenotypic (IC50 determination, migration, proliferation and angiogenesis assay, DNA damage analysis) and transcriptomic consequences (NGS) of RUNX3 TV1 and TV2 overexpression. Platinum sensitivity was affected by a specific transcript variant depending on BRCA background. RUNX3 TV2 induced an increased sensitivity in BRCA1wt cells (OVCAR3), whereas TV1 increased the sensitivity and induced a G2/M arrest under treatment in BRCA1mut cells (A13-2-12). These different phenotypes relate to differences in DNA repair: homologous recombination deficient A13-2-12 cells show less γH2AX foci despite higher levels of Pt-DNA adducts. RNA-Seq analyses prove transcript variant and cell-line-specific RUNX3 effects. Pathway analyses revealed another clinically important function of RUNX3—regulation of angiogenesis. This was confirmed by thrombospondin1 analyses, HUVEC spheroid sprouting assays and proteomic profiling. Importantly, conditioned media (CM) from RUNX3 TV1 overexpressing A13-2-12 cells induced an increased HUVEC sprouting. Altogether, the presented data support the hypothesis of different functions of RUNX3 transcript variants related to the clinically relevant processes—platinum resistance and angiogenesis

    Antibody-induced erythrophagocyte reprogramming of Kupffer cells prevents anti-CD40 cancer immunotherapy-associated liver toxicity

    Full text link
    BackgroundAgonistic anti-CD40 monoclonal antibodies (mAbs) have emerged as promising immunotherapeutic compounds with impressive antitumor effects in mouse models. However, preclinical and clinical studies faced dose-limiting toxicities mediated by necroinflammatory liver disease. An effective prophylactic treatment for liver immune-related adverse events that does not suppress specific antitumor immunity remains to be found.MethodsWe used different mouse models and time-resolved single-cell RNA-sequencing to characterize the pathogenesis of anti-CD40 mAb induced liver toxicity. Subsequently, we developed an antibody-based treatment protocol to selectively target red blood cells (RBCs) for erythrophagocytosis in the liver, inducing an anti-inflammatory liver macrophage reprogramming.ResultsWe discovered that CD40 signaling in Clec4f+^{+}Kupffer cells is the non-redundant trigger of anti-CD40 mAb-induced liver toxicity. Taking advantage of the highly specific functionality of liver macrophages to clear antibody-tagged RBCs from the blood, we hypothesized that controlled erythrophagocytosis and the linked anti-inflammatory signaling by the endogenous metabolite heme could be exploited to reprogram liver macrophages selectively. Repeated low-dose administration of a recombinant murine Ter119 antibody directed RBCs for selective phagocytosis in the liver and skewed the phenotype of liver macrophages into a Hmoxhigh^{high}/Marcohigh^{high}/MHCIIlow^{low}anti-inflammatory phenotype. This unique mode of action prevented necroinflammatory liver disease following high-dose administration of anti-CD40 mAbs. In contrast, extrahepatic inflammation, antigen-specific immunity, and antitumor activity remained unaffected in Ter119 treated animals.ConclusionsOur study offers a targeted approach to uncouple CD40-augmented antitumor immunity in peripheral tissues from harmful inflammatoxicity in the liver

    Repression of human papillomavirus oncogene expression under hypoxia is mediated by PI3K/mTORC2/AKT signaling

    Get PDF
    Oncogenic HPV types are major human carcinogens. Under hypoxia, HPV-positive cancer cells can repress the viral E6/E7 oncogenes and induce a reversible growth arrest. This response could contribute to therapy resistance, immune evasion, and tumor recurrence upon reoxygenation. Here, we uncover evidence that HPV oncogene repression is mediated by hypoxia-induced activation of canonical PI3K/mTORC2/AKT signaling. AKT-dependent downregulation of E6/E7 is only observed under hypoxia and occurs, at least in part, at the transcriptional level. Quantitative proteome analyses identify additional factors as candidates to be involved in AKT-dependent E6/E7 repression and/or hypoxic PI3K/mTORC2/AKT activation. These results connect PI3K/mTORC2/AKT signaling with HPV oncogene regulation, providing new mechanistic insights into the cross talk between oncogenic HPVs and their host cells.Hypoxia is linked to therapeutic resistance and poor clinical prognosis for many tumor entities, including human papillomavirus (HPV)-positive cancers. Notably, HPV-positive cancer cells can induce a dormant state under hypoxia, characterized by a reversible growth arrest and strong repression of viral E6/E7 oncogene expression, which could contribute to therapy resistance, immune evasion and tumor recurrence. The present work aimed to gain mechanistic insights into the pathway(s) underlying HPV oncogene repression under hypoxia. We show that E6/E7 downregulation is mediated by hypoxia-induced stimulation of AKT signaling. Ablating AKT function in hypoxic HPV-positive cancer cells by using chemical inhibitors efficiently counteracts E6/E7 repression. Isoform-specific activation or downregulation of AKT1 and AKT2 reveals that both AKT isoforms contribute to hypoxic E6/E7 repression and act in a functionally redundant manner. Hypoxic AKT activation and consecutive E6/E7 repression is dependent on the activities of the canonical upstream AKT regulators phosphoinositide 3-kinase (PI3K) and mechanistic target of rapamycin (mTOR) complex 2 (mTORC2). Hypoxic downregulation of E6/E7 occurs, at least in part, at the transcriptional level. Modulation of E6/E7 expression by the PI3K/mTORC2/AKT cascade is hypoxia specific and not observed in normoxic HPV-positive cancer cells. Quantitative proteome analyses identify additional factors as candidates to be involved in hypoxia-induced activation of the PI3K/mTORC2/AKT signaling cascade and in the AKT-dependent repression of the E6/E7 oncogenes under hypoxia. Collectively, these data uncover a functional key role of the PI3K/mTORC2/AKT signaling cascade for viral oncogene repression in hypoxic HPV-positive cancer cells and provide new insights into the poorly understood cross talk between oncogenic HPVs and their host cells under hypoxia

    Fine-mapping of the HNF1B multicancer locus identifies candidate variants that mediate endometrial cancer risk.

    Get PDF
    Common variants in the hepatocyte nuclear factor 1 homeobox B (HNF1B) gene are associated with the risk of Type II diabetes and multiple cancers. Evidence to date indicates that cancer risk may be mediated via genetic or epigenetic effects on HNF1B gene expression. We previously found single-nucleotide polymorphisms (SNPs) at the HNF1B locus to be associated with endometrial cancer, and now report extensive fine-mapping and in silico and laboratory analyses of this locus. Analysis of 1184 genotyped and imputed SNPs in 6608 Caucasian cases and 37 925 controls, and 895 Asian cases and 1968 controls, revealed the best signal of association for SNP rs11263763 (P = 8.4 × 10(-14), odds ratio = 0.86, 95% confidence interval = 0.82-0.89), located within HNF1B intron 1. Haplotype analysis and conditional analyses provide no evidence of further independent endometrial cancer risk variants at this locus. SNP rs11263763 genotype was associated with HNF1B mRNA expression but not with HNF1B methylation in endometrial tumor samples from The Cancer Genome Atlas. Genetic analyses prioritized rs11263763 and four other SNPs in high-to-moderate linkage disequilibrium as the most likely causal SNPs. Three of these SNPs map to the extended HNF1B promoter based on chromatin marks extending from the minimal promoter region. Reporter assays demonstrated that this extended region reduces activity in combination with the minimal HNF1B promoter, and that the minor alleles of rs11263763 or rs8064454 are associated with decreased HNF1B promoter activity. Our findings provide evidence for a single signal associated with endometrial cancer risk at the HNF1B locus, and that risk is likely mediated via altered HNF1B gene expression

    Papillomavirus Capsid Binding and Uptake by Cells From Different Tissues and Species

    Get PDF
    The inability of papillomaviruses (PV) to replicate in tissue culture cells has hampered the study of the PV life cycle. We investigated virus-cell interactions by the following two methods: (i) using purified bovine PV virions or human PV type 11 (HPV type 11) virus-like particles (VLP) to test the binding to eukaryotic cells and (ii) using different VLP-reporter plasmid complexes of HPV6b, HPV11 L1 or HPV11 L1/L2, and HPV16 L1 or HPV16 L1/L2 to study uptake of particles into different cell lines. Our studies showed that PV capsids bind to a broad range of cells in culture in a dose-dependent manner. Binding of PV capsids to cells can be blocked by pretreating the cells with the protease trypsin. Penetration of PV into cells was monitored by using complexes in which the purified PV capsids were physically linked to DNA containing the gene for beta-galactosidase driven by the human cytomegalovirus promoter. Expression of beta-galactosidase occurred in < 1% of the cells, and the efficiency of PV receptor-mediated gene delivery was greatly enhanced (up to 10 to 20% positive cells) by the use of a replication-defective adenovirus which promotes endosomal lysis. The data generated by this approach further confirmed the results obtained from the binding assays, showing that PV enter a wide range of cells and that these cells have all functions required for the uptake of PV. Binding and uptake of PV particles can be blocked by PV-specific antisera, and different PV particles compete for particle uptake. Our results suggest that the PV receptor is a conserved cell surface molecule(s) used by different PV and that the tropism of infection by different PV is controlled by events downstream of the initial binding and uptake

    Prevalence and determinants of human papillomavirus genital infection in men

    Get PDF
    Four-hundred-forty-five husbands of women with invasive cervical carcinoma, 165 of women with in situ cervical cancer, and 717 of control women (age range 19–82 years) were interviewed and a sample of exfoliated cells from the penis obtained in seven case–control studies conducted by the International Agency for Research on Cancer. The characteristics of human papillomavirus-positive and human papillomavirus-negative husbands were compared using odds ratios and 95% confidence intervals. Thirteen per cent of the husbands of control women, 18% of the husbands of women with invasive cervical carcinoma, and 21% of the husbands of in situ cervical carcinoma women were positive for penile human papillomavirus DNA. Human papillomavirus 16 was detected in 45 husbands, human papillomavirus 18, 31 or 33 in 19, and human papillomavirus 6/11 in 6, but the majority of human papillomavirus infection (158) was with other or unspecified human papillomavirus types. The same human papillomavirus type was seldom identified in both husband and wife. The strongest variation in penile human papillomavirus infection was by country, with percentages among the husbands of control women ranging between 3% in Spain and 39% in Brazil. Having had over 50 lifetime sexual partners, compared with only one, was associated with an odds ratio of 2.3
    • …
    corecore