80 research outputs found

    Origin Effect A Case Study of a Swedish Multinational Company

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    Nota: Las reglas de escritura de las referencias bibliográficas pueden variar según los diferentes dominios del conocimiento. Este documento está protegido por la ley de derechos de autor. La utilización de los servicios de Érudit (comprendida la reproducción) se rige por su política de utilización que se puede consultar en el UR

    The role of relaxin in the regulation of human liver and kidney fibrosis

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    Liver fibrosis has a range of aetiologies and is a global cause of mortality. Acritical effect of liver fibrosis which also increases mortality is portalhypertension. The hepatic stellate cell is accepted as a major progenitor of livermyofibroblasts, which have been shown to be a major source of collagen andextracellular matrix proteins that disrupt liver architecture and function. Relaxinis a hormone involved in remodelling of extracellular matrix in the uterus andcervix and is known to increase renal blood flow in pregnancy. It has beenimplicated in the regulation of fibrosis in animal models and to modify the cellbiology of hepatic stellate cells in vitro. I have demonstrated the profile ofexpression of relaxin receptors in primary human stellate cells (HSC), showingthem to express RXFP-1, 3 and 4. Using a cAMP assay I confirm these receptorsto be functional, with RXFP-1 positively and RXFP-3 and 4 negatively couplingto cAMP. The expression of RXFP-1 is coupled with the level of activation,demonstrating a possible role for H2-relaxin in the regulation of HSC. I haveestablished a dynamic regulation of fibrotic mediators and HSC activationmarkers, including a reduction in ?-SMA, TIMP-1 and TGF-? with increases inMMP-1 and MMP-2, consistent with H2-relaxin having potentially therapeuticantifibrotic effects by increasing the fibrolytic phenotype. In addition throughthe use of gel contraction assays I demonstrate that H2-relaxin reduces serum orendothelin-1 induced HSC contraction. Through the use of siRNA I haveconfirmed that H2-relaxin mediates its regulation of fibrotic mediators and HSCactivation markers as well as the inhibition of gel contraction through the relaxinreceptor RXFP-1. I have evidence to suggest that the inhibition of contractionmay in part be via nitric oxide release in HSC. In conclusion I propose thatRXFP-1 is a potential therapeutic target in end stage human liver disease,targeting fibrosis and portal blood hypertension via both resolution of thephenotypic collagen deposition and vascular constriction associated with thehuman hepatic stellate cell

    Novel roles for adenomatous polyposis coli family members and wingless signaling in cell adhesion and axon outgrowth during Drosophila brain development

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    Mutation in the tumor suppressor gene, adenomatous polyposis coli (APC), leads to the initiation of colon cancer. Both Drosophila and mammals have two APC family members, APC1 and APC2. Our lab and others have characterized both Drosophila family members in the developing embryonic epidermis. In addition, we characterized the expression of both in the developing larval brain. Construction of the brain is one of the most complex developmental challenges. Wnt signals shape all tissues, including the brain, and the APC is a key negative regulator of Wnt/Wingless (Wg) signaling. We carried out the first assessment of the role of APC proteins in brain development, simultaneously inactivating both APC1 and APC2 in clones of cells in the Drosophila larval optic lobe. Loss of both APCs triggers dramatic defects in optic lobe development. Double mutant cells segregate from wild-type neighbors to form epithelial "loops", while double mutant neurons form tangled axonal "knots", suggesting changes in cell adhesion. Activation of Wg signaling downstream of APC mimics these phenotypes, a dominant-negative TCF construct blocks them, and a known Wg target, Decapentaplegic, is activated in double mutant clones. These results strongly suggest that the phenotypes result from activated Wg signaling. We also explored the roles of classic cadherins in differential adhesion. Finally, we propose a model suggesting that Wg signaling regulates fine scale cell fates along the anterior-posterior axis in the developing larval brain, in part by creating an adhesion gradient

    Fibroblasts derived from oesophageal adenocarcinoma differ in DNA methylation profile from normal oesophageal fibroblasts

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    Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Oesophageal adenocarcinoma (OAC) is increasing in incidence and has a poor prognosis. Tumour derived fibroblasts (TDFs) differ functionally from normal fibroblasts (NDFs), and play a pivotal role in cancer. Many of the differences persist through subculture. We measured the DNA methylation profiles of 10 TDFs from OAC with 12 NDF from normal oesophageal mucosa using Infinium HumanMethylation450 Beadchips and found they differed in multidimensional scaling analysis. We identified 4,856 differentially methylated CpGs (DMCs, adjusted p  0.15), of which 3,243 (66.8%) were hypomethylated in TDFs compared to NDFs. Hypermethylated DMCs were enriched at transcription start sites (TSSs) and in CpG islands, and depleted in transcriptional enhancers. Gene ontology analysis of genes with DMCs at TSSs revealed an enrichment of genes involved in development, morphogenesis, migration, adhesion, regulation of processes and response to stimuli. Alpha-smooth muscle actin (α-SMA) is a marker of activated fibroblasts and a poor prognostic indicator in OAC. Hypomethylated DMCs were observed at the TSS of transcript variant 2 of α-SMA, which correlated with an increase in α-SMA protein expression. These data suggest that DNA methylation may contribute to the maintenance of the TDF phenotype

    Veteran adherence to oral versus injectable AUD medication treatment

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    Introduction: AUD medication treatment has been shown to improve outcomes compared with placebo when confined to per-protocol analysis. The same outcomes, however, have not always been maintained in intent-to-treat analysis, thus suggesting adherence may have a significant impact on efficacy outcomes. There is conflicting evidence present in the literature comparing adherence to oral versus injectable AUD pharmacotherapy and a paucity of information in the veteran population on risk factors for low adherence. Methods: The primary end point of this retrospective chart review was to determine whether adherence rates differ between oral and injectable AUD treatments in veterans during the first year of treatment (at 3, 6, 9, and 12 months) using the portion of days covered model. Secondary end points were to determine differing characteristics between patients with high versus low adherence and compare alcohol-related readmission rates and discontinuation rates between groups. Results: Adherence to injectable extended-release (XR) naltrexone was significantly higher than oral naltrexone at all time points and was significantly higher than disulfiram at 3, 6, and 9 months, but it was not significantly different from acamprosate at any time point. At months 9 and 12, acamprosate had significantly higher adherence compared with oral naltrexone. Patients with higher adherence were seen more frequently in the mental health clinic and had previously tried more AUD medications. The discontinuation rates and alcohol-related admission rates were not significantly different between groups at 1 year. Discussion: XR naltrexone may improve adherence rates compared with oral naltrexone or disulfiram, but not acamprosate based on these outcomes. Patients may have increased adherence if they are seen more often in clinic and have trialed more AUD medications

    Cancer associated fibroblasts predict for poor outcome and promote periostin-dependent invasion in oesophageal adenocarcinoma

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    Interactions between cancer cells and cancer-associated fibroblasts (CAF) play an important role in tumour development and progression. In this study we investigated the functional role of CAF in oesophageal adenocarcinoma (EAC). We used immunochemistry to analyse a cohort of EAC patients (183 patients) for CAF markers related to disease mortality. We characterized CAF and normal oesophageal fibroblasts (NOF) using western blotting, immunofluorescence and gel contraction. Transwell assays, 3-D organotypic culture and xenograft models were used to examine effects on EAC cell function, and dissect molecular mechanisms regulating invasion. Most EAC (93%) contained CAF with a myofibroblastic (?-SMA-positive) phenotype, which correlated significantly with poor survival (p?=?0.016; HR 7. 1 (1.7-29.4). Primary CAF, isolated from EAC, have a contractile, myofibroblastic phenotype, and promote EAC cell invasion in vitro (Transwell assays, p?=?<0.05; organotypic culture, p?<?0.001) and in vivo (p?=?<0.05). In vitro, this pro-invasive effect is modulated through the matricellular protein periostin. Periostin is secreted by CAF, and acts as a ligand for EAC cell integrins ?v?3 and ?v?5, promoting activation of the PI3kinase/Akt pathway. In patient samples, periostin expression at the tumour cell/stromal interface correlates with poor overall and disease-free survival. Our study highlights the importance of the tumour stroma in EAC progression. Paracrine interaction between CAF-secreted periostin and EAC-expressed integrins results in PI3 kinase/Akt activation and increased tumour cell invasion. Most EAC contain a myofibroblastic CAF-rich stroma; this may explain the aggressive, highly infiltrative nature of the disease, and suggests that stromal targeting may produce therapeutic benefit in EAC patient

    Modulation of the tumour promoting functions of cancer associated fibroblasts by phosphodiesterase type 5 inhibition increases the efficacy of chemotherapy in human preclinical models of esophageal adenocarcinoma

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    Background and aims: Esophageal adenocarcinoma (EAC) is chemoresistant in the majority of cases. The tumor-promoting biology of cancer associated fibroblasts (CAF) make them a target for novel therapies. Phosphodiesterase type 5 inhibitors (PDE5i) have been shown to regulate the activated fibroblast phenotype in benign disease. We investigated the potential for CAF modulation in EAC using PDE5i to enhance the efficacy of chemotherapy. Methods: EAC fibroblasts were treated with PDE5i and phenotypic effects examined using immunoblotting, immunohistochemistry, gel contraction, transwell invasion, organotypics, single cell RNAseq and shotgun proteomics. The combination of PDE5i with standard-of-care chemotherapy (Epirubicin, 5-Fluorouracil and Cisplatin) was tested for safety and efficacy in validated near-patient model systems (3D tumor growth assays (3D-TGAs) and patient derived xenograft (PDX) mouse models). Results: PDE5i treatment reduced alpha-SMA expression in CAFs by 50% (p<0.05), associated with a significant reduction in the ability of CAFs to contract collagen-1 gels and induce cancer cell invasion, (p<0.05). RNAseq and proteomic analysis of CAF and EAC cell lines revealed PDE5i specific regulation of pathways related to fibroblast activation and tumor promotion. 3D-TGA assays confirmed the importance of stromal cells to chemoresistance in EAC, which could be attenuated by PDE5i. Chemotherapy+PDE5i in PDX-bearing mice was safe and significantly reduced PDX tumor volume (p<0.05). Conclusion: PDE5 is a candidate for clinical trials to alter the fibroblast phenotype in esophageal cancer. We demonstrate the specificity of PDE5i for fibroblasts to prevent transdifferentiation and revert the CAF phenotype. Finally, we confirm the efficacy of PDE5i in combination with chemotherapy in close-to-patient in vitro and in vivo PDX-based model systems

    A subset of myofibroblastic cancer-associated fibroblasts regulate collagen fiber elongation, which is prognostic in multiple cancers

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    Collagen structure has been shown to influence tumor cell invasion, metastasis and clinical outcome in breast cancer. However, it remains unclear how it affects other solid cancers. Here we utilized multi-photon laser scanning microscopy and Second Harmonic Generation to identify alterations to collagen fiber structure within the tumor stroma of head &amp; neck, esophageal and colorectal cancers. Image segmentation algorithms were then applied to quantitatively characterize these morphological changes, showing that elongated collagen fibers significantly correlated with poor clinical outcome (Log Rank p &lt; 0.05). We used TGF-? treatment to model fibroblast conversion to smooth muscle actin SMA-positive cancer associated fibroblasts (CAFs) and found that these cells induce the formation of elongated collagen fibers in vivo. However, proteomic/transcriptomic analysis of SMA-positive CAFs cultured ex-vivo showed significant heterogeneity in the expression of genes with collagen fibril organizing gene ontology. Notably, stratifying patients according to stromal SMA-positivity and collagen fiber elongation was found to provide a highly significant correlation with poor survival in all 3 cancer types (Log Rank p ? 0.003). In summary, we show that increased collagen fiber length correlates with poor patient survival in multiple tumor types and that only a sub-set of SMA-positive CAFs can mediate the formation of this collagen structure

    t4 Workshop Report: Integrated Testing Strategies (ITS) for Safety Assessment

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    Integrated testing strategies (ITS), as opposed to single definitive tests or fixed batteries of tests, are expected to efficiently combine different information sources in a quantifiable fashion to satisfy an information need, in this case for regulatory safety assessments. With increasing awareness of the limitations of each individual tool and the development of highly targeted tests and predictions, the need for combining pieces of evidence increases. The discussions that took place during this workshop, which brought together a group of experts coming from different related areas, illustrate the current state of the art of ITS, as well as promising developments and identifiable challenges. The case of skin sensitization was taken as an example to understand how possible ITS can be constructed, optimized and validated. This will require embracing and developing new concepts such as adverse outcome pathways (AOP), advanced statistical learning algorithms and machine learning, mechanistic validation and “Good ITS Practices”.JRC.I.5-Systems Toxicolog
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