Our data indicate that ECP stimulates the conversion of ATP to adenosine by the ectonucleotiodase CD39, which acts as a novel soluble immunosuppressive reagent mediating immunosuppression of Treg.

No abstract

Stability of many tumor-relevant proteins is partly mediated by E3 ligases, which determine substrate specificity within the ubiquitin system. Recent data demonstrated that increased nuclear expression of the E3 ligase seven in absentia homologue (SIAH)-1 in human hepatocarcinogenesis supports tumor cell proliferation and migration. To define whether closely related SIAH-2 synergizes with protumorigenic SIAH-1, we systematically analyzed expression, localization and functional relevance of SIAH-2 in human hepatocellular carcinoma (HCC). Nuclear accumulation of SIAH-2 is detectable in more than 60% of all HCCs and correlates with tumor progression, cell proliferation and distant metastasis. An inverse correlation between nuclear SIAH-1 and SIAH-2 was detected, suggesting independent mechanisms for nuclear enrichment. Inhibition of nuclear SIAH-2 by RNAi in HCC cell lines reduced proliferation as well as lateral tumor cell motility and transmigration; however, combined knock down of both SIAH-1 and SIAH-2 did not further amplify biological effects compared to single gene inhibition. Reduction of SIAH-2 expression sensitizes HCC cells to the treatment with different cytostatic drugs, demonstrating that SIAH-2-targeting approaches may increase the response of HCC cells to conventional chemotherapy. Together, these data show that SIAH-2-as described for SIAH-1-accumulates in nuclei of HCC cells where it supports tumor growth and tumor cell dissemination. Because the nuclear pattern of SIAH-2 differs in HCC tissues from the SIAH-1 pattern and because the inactivation of SIAH-2 is not compensated by SIAH-1, the specific inhibition of SIAH-2 (especially in combination with other drugs) represents a promising therapeutic strategy for HCC.The ubiquitin-proteasome system controls bioactivity, localization and protein turnover based on the sequential impact of E1 ubiquitin-activating enzymes, E2 ubiquitin-conjugating enzymes and E3 ubiquitin-protein ligases.1 Substrate proteins are subjected to ubiquitination associated with different fates of the targeted protein; in case of polyubiquitination, targets are mostly degraded, while in the case of monoubiquitination, substrate activity or subcellular localization is affected.2 Consequently, the ubiquitin-conjugating system regulates different cellular processes such as mitosis, apoptosis and genomic integrity under physiological and pathophysiological conditions.In human carcinogenesis, accumulation of oncogenes (e.g., c-MYC) and ablation of tumor suppressors (e.g., p53) are frequently influenced by the bioactivity of E3 ligases. This family of more than 600 members contains specific ligase proteins (e.g., BRCA1) as well as multisubunit ligases (e.g., SCF-Skp2), which, together with respective E2 conjugating factors, define substrate specificity. 3 In addition, recent data demonstrated that the proteasome system improves cell vitality in the presence of aneuploidy, which is a key characteristic of many solid tumors. 4 Because dysfunction of the ubiquitin-proteasome system affe...

Cutaneous regeneration utilizes paracrine feedback mechanisms to fine-tune the regulation of epidermal keratinocyte proliferation and migration. However, it is unknown how fibroblast-derived hepatocyte growth factor (HGF) affects these mutually exclusive processes in distinct cell populations. We here show that HGF stimulates the expression and phosphorylation of the microtubule-destabilizing factor stathmin in primary human keratinocytes. Quantitative single cell- and cell population-based analyses revealed that basal stathmin levels are important for the migratory ability of keratinocytes in vitro; however, its expression is moderately induced in the migration tongue of mouse skin or organotypic multi-layered keratinocyte 3D cultures after full-thickness wounding. In contrast, clearly elevated stathmin expression is detectable in hyperproliferative epidermal areas. In vitro, stathmin silencing significantly reduced keratinocyte proliferation. Automated quantitative and time-resolved analyses in organotypic cocultures demonstrated a high correlation between Stathmin/phospho-Stathmin and Ki67 positivity in epidermal regions with proliferative activity. Thus, activation of stathmin may stimulate keratinocyte proliferation, while basal stathmin levels are sufficient for keratinocyte migration during cutaneous regeneration.

An effective means to analyze mRNA expression data is to take advantage of established knowledge from pathway databases, using methods such as pathway-enrichment analyses. However, pathway databases are not casespecific and expression data could be used to infer gene-regulation patterns in the context of specific pathways. In addition, canonical pathways may not always describe the signaling mechanisms properly, because interactions can frequently occur between genes in different pathways. Relatively few methods have been proposed to date for generating and analyzing such networks, preserving the causality between gene interactions and reasoning over the qualitative logic of regulatory effects. We present an algorithm (MCWalk) integrated with a logic programming approach, to discover subgraphs in large-scale signaling networks by random walks in a fully automated pipeline. As an exemplary application, we uncover the signal transduction mechanisms in a gene interaction network describing hepatocyte growth factor-stimulated cell migration and proliferation from geneexpression measured with microarray and RT-qPCR using in-house perturbation experiments in a keratinocyte-fibroblast co-culture. The resulting subgraphs illustrate possible associations of hepatocyte growth factor receptor c-Met nodes, differentially expressed genes and cellular states. Using perturbation experiments and Answer Set programming, we are able to select those which are more consistent with the experimental data. We discover key regulator nodes by measuring the frequency with which they are traversed when connecting signaling between receptors and significantly regulated genes and predict their expression-shift consistently with the measured data. The Java implementation of MCWalk is publicly available under the MIT license at: https://bitbucket.org/akittas/biosubg.

Availability of high-quality human tissue samples and access to associated histopathological and clinical data is essential for basic and translational biomedical research, especially in areas of personalized medicine, drug, and biomarker development and mechanistically oriented biomedical research projects. Therefore, it is pivotal to establish and maintain quality-assured tissue biobanks that provide high-quality biomaterial to research thereby increasing the impact and reliability of scientific results. Quality concerns do not only address the biomaterial specimen itself but include all biobanking-related procedures. Tissue biobanks thus face essential challenges that encompass the implementation of adequate structural components, documentation of tissue sample collection and storage (procedures), as well as data and project management and IT. An integral and indispensable component of tissue biobanks is expert-driven evaluation (entry and exit controls) of tissue specimen to guarantee provision of high-quality assured biomaterials.

A qualified and comprehensive supply of outpatient smoking cessation counselling and treatment is essential to help smokers quit. In order to assess the status quo, structure and regional differences of the smoking cessation services available in Germany, a complete market survey was conducted in 2007. Descriptive results on the structure and characteristics of smoking cessation services show that there are distinct regional differences, especially in the New Laender, where the supply is insufficient. Overall, about a quarter of the providers of smoking cessation services lack specialised additional skills required for smoking cessation counselling, treatment or therapy of addicts. Especially medical practitioners more often lack such additional skills compared to other occupational groups. The smoking cessation services generally used the programs "Rauchfrei in 10 Schritten" and "Das Rauchfrei Programm", and the method of cognitive behavioural therapy. However, more than half of the services still use a method which is not evidence-based. Since February 2008 data on all supplies and suppliers of smoking cessation services, who gave their permission, have been published online and can be accessed at www.anbieter-raucherberatung.de.

The objective of the present investigation was to evaluate potential of nanoemulsions as a coating material for the tablets. The nanoemulsion of size less than 100 nm was prepared using a simple and low-energy spontaneous emulsification method. Conventional tablets containing theophylline as a model hydrophilic drug were prepared. The theophylline tablets were coated with the nanoemulsion using a fluid bed coater. The effect of different levels of the nanoemulsion coating on the theophylline release was evaluated. The theophylline tablets containing different levels of the nanoemulsion coating could be successfully prepared. Interestingly, the coating of tablet with the nanoemulsion resulted in zero-order release of theophylline from the tablets. The noncoated theophylline tablets release the entire drug in less than 2 minutes, whereas nanoemulsion coating delayed the release of theophylline from tablets. This investigation establishes the proof of concept for the potential of nanoemulsions as a coating material for tablets.