965 research outputs found

    The promoter of human p22/PACAP response gene 1 (PRG1) contains functional binding sites for the p53 tumor suppressor and for NFκB

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    AbstractWe describe functional binding sites for the tumor suppressor p53 and for NFκB residing in the promoter of the novel human early response gene p22/PRG1 (IEX-1/DIF-2). Gel shift and supershift assays demonstrate binding of p53 and NFκB to their corresponding sites in vitro. CAT-reporter gene assays show transactivation of the human p22/PRG1 promoter by p53 in Hep3B cells stably transfected with a temperature-sensitive mutant p53, but not in p53-deficient Hep3B cells. TNFα induced NFκB dependent transactivation was shown in HepG2 cells or in 818-4 pancreatic cancer cells. These data imply that human p22/PRG1 is a target gene for p53 and NFκB involved in growth regulation and stress response

    Arrow R-CNN for handwritten diagram recognition

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    L1CAM expression in endometrial carcinomas is regulated by usage of two different promoter regions

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    <p>Abstract</p> <p>Background</p> <p>The L1 cell adhesion molecule (L1CAM) was originally identified as a neural adhesion molecule involved in axon guidance. In many human epithelial carcinomas L1CAM is overexpressed and thereby augments cell motility, invasion and metastasis formation. L1CAM positive carcinomas are associated with bad prognosis. Recent data point out that L1CAM is regulated in a fashion similar to epithelial-mesenchymal transition (EMT). Previous studies have implied the transcription factors Slug and/or β-catenin in <it>L1CAM </it>transcriptional regulation. However, the regulation of human L1CAM expression at the transcriptional level is not well understood.</p> <p>Results</p> <p>To better understand the molecular basis of <it>L1CAM </it>transcriptional regulation, we carried out a detailed characterization of the human <it>L1CAM </it>promoter. We identified two transcription start sites, the first in front of a non-translated exon 0 (promoter 1) and the other next to the first protein-coding exon 1 (promoter 2). Both sites could be verified in endometrial carcinoma (EC) cell lines and appear to be used in a cell-type specific manner. The two identified promoter regions showed activity in luciferase reporter assays. Chromatin-IP analyses confirmed the <it>in silico </it>predicted E-boxes, binding sites for transcription factors Snail and Slug, as well as Lef-1 sites, which are related to β-catenin-mediated transcriptional regulation, in both promoters. Overexpression of β-catenin exclusively augmented activity of promoter 1 whereas Slug enhanced promoter 1 and 2 activity suggesting that both promoters can be active. Overexpression of β-catenin or Slug could upregulate L1CAM expression in a cell-type specific manner.</p> <p>Conclusions</p> <p>Our results, for the first time, provide evidence that the L1CAM gene has two functionally active promoter sites that are used in a cell-type specific manner. Slug and β-catenin are involved <it>L1CAM </it>transcriptional regulation. Nevertheless, Slug rather than β-catenin levels are correlated with L1CAM expression in EC cell lines. Our findings suggest that the <it>L1CAM </it>transcriptional regulation is more complex than anticipated and this study provides the basis for a better understanding of L1CAM regulation in non-neuronal/tumor cells.</p

    Fidelity and level correlations in the transition from regularity to chaos

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    Mean fidelity amplitude and parametric energy--energy correlations are calculated exactly for a regular system, which is subject to a chaotic random perturbation. It turns out that in this particular case under the average both quantities are identical. The result is compared with the susceptibility of chaotic systems against random perturbations. Regular systems are more susceptible against random perturbations than chaotic ones.Comment: 7 pages, 1 figur

    Identification of binding proteins for cholesterol absorption inhibitors as components of the intestinal cholesterol transporter

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    AbstractTo identify protein components of the intestinal cholesterol transporter, rabbit small intestinal brush border membrane vesicles were submitted to photoaffinity labeling using photoreactive derivatives of 2-azetidinone cholesterol absorption inhibitors. An integral membrane protein of Mr 145.3±7.5 kDa was specifically labeled in brush border membrane vesicles from rabbit jejunum and ileum. Its labeling was concentration-dependently inhibited by the presence of cholesterol absorption inhibitors whereas bile acids, D-glucose, fatty acids or cephalexin had no effect. The inhibitory potency of 2-azetidinones to inhibit photolabeling of the 145 kDa protein correlated with their in vivo activity to inhibit intestinal cholesterol absorption. These results suggest that an integral membrane protein of Mr 145 kDa is (a component of) the cholesterol absorption system in the brush border membrane of small intestinal enterocytes

    Initiation of Pancreatic Cancer: The Interplay of Hyperglycemia and Macrophages Promotes the Acquisition of Malignancy-Associated Properties in Pancreatic Ductal Epithelial Cells

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    Pancreatic ductal adenocarcinoma (PDAC) is still one of the most aggressive solid malignancies with a poor prognosis. Obesity and type 2 diabetes mellitus (T2DM) are two major risk factors linked to the development and progression of PDAC, both often characterized by high blood glucose levels. Macrophages represent the main immune cell population in PDAC contributing to PDAC development. It has already been shown that pancreatic ductal epithelial cells (PDEC) undergo epithelial-mesenchymal transition (EMT) when exposed to hyperglycemia or macrophages. Thus, this study aimed to investigate whether concomitant exposure to hyperglycemia and macrophages aggravates EMT-associated alterations in PDEC. Exposure to macrophages and elevated glucose levels (25 mM glucose) impacted gene expression of EMT inducers such as IL-6 and TNF-α as well as EMT transcription factors in benign (H6c7-pBp) and premalignant (H6c7-kras) PDEC. Most strikingly, exposure to hyperglycemic coculture with macrophages promoted downregulation of the epithelial marker E-cadherin, which was associated with an elevated migratory potential of PDEC. While blocking IL-6 activity by tocilizumab only partially reverted the EMT phenotype in H6c7-kras cells, neutralization of TNF-α by etanercept was able to clearly impair EMT-associated properties in premalignant PDEC. Altogether, the current study attributes a role to a T2DM-related hyperglycemic, inflammatory micromilieu in the acquisition of malignancy-associated alterations in premalignant PDEC, thus providing new insights on how metabolic diseases might promote PDAC initiation

    Insulin Receptor in Pancreatic Cancer-Crown Witness in Cross Examination

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    Background The proximity of pancreatic cancer (PDAC) to the physiological source of the growth promoting hormone insulin might be exploited by this highly malignant cancer entity. We investigated if (I) PDACs express the insulin receptor (IR) in cancer cells and cancer vasculature, (II) if IR correlates with clinicopathological patient characteristics, including survival, and hence is involved in PDAC biology, (III) if IR is already expressed in precursor lesions, if (IV) the IGF1 receptor (IGF1R) is associated with clinicopathological patient characteristics and survival and (V) is linked to IR expression. Methods 160 PDAC samples were examined for IR and IGF1R expression by immunohistochemistry. A modified HistoScore was correlated with clinicopathological characteristics and survival. Results IR overexpression was already observed in pancreatic intraepithelial neoplasia. Furthermore, it was more frequently observed in advanced disease and associated with distant metastasis, UICC stage, lymphatic invasion and an increased lymph node ratio, but without impacting survival in the end. IGF1R expression was not associated with clinicopathological parameters or survival, in contrast to former paradigms. Conclusions We hypothesize that the close proximity to the pancreatic islets might be advantageous for cancer growth at first, but it experiences self-limitation due to surgical removal or local destruction following accelerated cancer growth
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