A crucial cause of the decreased bioactivity of nitric oxide (NO) in cardiovascular diseases is the uncoupling of the endothelial NO synthase (eNOS) caused by the oxidative stress-mediated deficiency of the NOS cofactor tetrahydrobiopterin (BH 4 ). The reversal of eNOS uncoupling might represent a novel therapeutic approach. The treatment of apolipoprotein E knockout (ApoE-KO) mice with resveratrol resulted in the up-regulation of superoxide dismutase (SOD) isoforms (SOD1-SOD3), glutathione peroxidase 1 (GPx1), and catalase and the down-regulation of NADPH oxidases NOX2 and NOX4 in the hearts of ApoE-KO mice. This was associated with reductions in superoxide, 3-nitrotyrosine, and malondialdehyde levels. In parallel, the cardiac expression of GTP cyclohydrolase 1 (GCH1), the rate-limiting enzyme in BH 4 biosynthesis, was enhanced by resveratrol. This enhancement was accompanied by an elevation in BH 4 levels. Superoxide production from ApoE-KO mice hearts was reduced by the NOS inhibitor L-N G -nitro-arginine methyl ester, indicating eNOS uncoupling in this pathological model. Resveratrol treatment resulted in a reversal of eNOS uncoupling. Treatment of human endothelial cells with resveratrol led to an up-regulation of SOD1, SOD2, SOD3, GPx1, catalase, and GCH1. Some of these effects were preventable with sirtinol, an inhibitor of the protein deacetylase sirtuin 1. In summary, resveratrol decreased superoxide production and enhanced the inactivation of reactive oxygen species. The resulting reduction in BH 4 oxidation, together with the enhanced biosynthesis of BH 4 by GCH1, probably was responsible for the reversal of eNOS uncoupling. This novel mechanism (reversal of eNOS uncoupling) might contribute to the protective effects of resveratrol.

Meaningful, reliable and valid mRNA expression analyses by real-time quantitative PCR (RT-qPCR) can only be achieved, if suitable reference genes are chosen for normalization and if appropriate RT-qPCRquality standards are met. Human periodontal ligament (hPDL) fibroblasts play a major mediating role in orthodontic tooth movement and periodontitis. Despite corresponding in-vitro gene expression studies being a focus of interest for many years, no information is available for hPDL fibroblasts on suitable reference genes, which are generally used in RT-qPCR experiments to normalize variability between samples. The aim of this study was to identify and validate suitable reference genes for normalization in untreated hPDL fibroblasts as well as experiments on orthodontic tooth movement or periodontitis (Aggregatibacter actinomycetemcomitans). We investigated the suitability of 13 candidate reference genes using four different algorithms (geNorm, NormFinder, comparative ΔC q and BestKeeper) and ranked them according to their expression stability. Overall PPIB (peptidylprolyl isomerase A), TBP (TATA-box-binding protein) and RPL22 (ribosomal protein 22) were found to be most stably expressed with two genes in conjunction sufficient for reliable normalization. This study provides an accurate tool for quantitative gene expression analysis in hPDL fibroblasts according to the MIQE guidelines and shows that reference gene reliability is treatment-specific.Orthodontics and periodontology are specialties of dentistry tending to the treatment of misaligned teeth/jaws and bacterially induced inflammation of the periodontal tissues (periodontitis), respectively, with several interactive associations existing 1 . In orthodontics mechanical forces applied to the teeth result in tensile and pressure zones within the periodontal ligament (PDL) 2 . PDL fibroblasts react to this mechanical strain with an increased synthesis of proinflammatory enzymes, cytokines and chemokines 2-4 , triggering osteoclastogenesis. Bacterial toxins from periodontal pathogens in periodontitis, such as the gram-negative Aggregatibacter actinomycetemcomitans (Agac), the key pathogen in aggressive periodontitis 5 , can in a similar way stimulate PDL fibroblasts, which are thus essential both for mediating orthodontic tooth movement and bacterial periodontitis.Real-time quantitative PCR (RT-qPCR) and DNA microarray analysis are the methods of choice to analyse transcription of cellular genes 6,7 . In contrast to microarray analysis, which allows expression profiling of a high number of genes, RT-qPCR enables a precise quantification of gene expression differences in physiological, pathological and various experimental states [8][9][10] . However, a reliable RT-qPCR setup is necessary to achieve valid results. To improve quality and reproducibility of RT-qPCR experiments, Bustin et al. published the MIQE guidelines 11 in 2009, detailing the minimum information for publication of quantitative real-time PCR experiments. A view in current literature shows that m...

hPDL fibroblasts seem to play a major mediating role in the early phase of OTM with a differentiated, time-dependent regulation and expression pattern of cytokines and other mediators.

An HPV infection is involved in the etiology of about 25 % of head and neck squamous cell carcinomas (HNSCC). It has been postulated that a strong antitumoral immune response in HPV-positive tumors represents an important underlying mechanism for their good response to therapy. Recently, the Warburg phenomenon has returned to the center of attention because it affects antitumoral immune response and response to therapy. Accumulation of tumor cell-derived lactate inhibits cytotoxic T cells, as these, analogous to cancer cells, depend on glycolysis and lactate secretion for fulfillment of energy needs. Sparse information exists on the Warburg effect in HNSCC. This study aimed to characterize the metabolic and immunological features of HPV-negative and HPV-positive HNSCC. An immunohistochemical analysis of oropharyngeal carcinomas showed an enhanced antitumoral immune response (CD8/CD4 ratio) together with increased levels of proteins involved in transmembranous metabolite transportation (GLUT1 and CD147) and respiratory metabolism (COX5B) in HPV-positive tumors as compared to HPV-negative tumors. mRNA and Western blot analyses of an HPV-positive and HPV-negative HNSCC cell line revealed metabolic characteristics similar to the in vivo situation. Additionally, the HPV-negative cell line showed stronger extracellular lactate accumulation. In contrast, the HPV-positive cell line presented with better adaption to lactic acidosis suggesting an ability to metabolize lactate. Our results indicate that HPV-positive and HPV-negative carcinomas do not only differ in terms of tumor immune microenvironment, but also in terms of tumor metabolism, characterized by an increased glucose and respiratory metabolism together with decreased lactate accumulation in HPV-positive HNSCC. Therefore, targeting metabolic pathways could represent a promising adjunct in the therapy of HPV-positive HNSCC.

The glucose transporter isoform 1 (GLUT1; SLC2A1) is a key rate-limiting factor in the transport of glucose into cancer cells. Enhanced GLUT1 expression and accelerated glycolysis have been found to promote aggressive growth in a range of tumor entities. However, it was unknown whether GLUT1 directly impacts metastasis. Here, we aimed at analyzing the expression and function of GLUT1 in malignant melanoma. Immunohistochemical analysis of 78 primary human melanomas on a tissue micro array showed that GLUT1 expression significantly correlated with the mitotic activity and a poor survival. To determine the functional role of GLUT1 in melanoma, we stably suppressed GLUT1 in the murine melanoma cell line B16 with shRNA. GLUT1 suppressed melanoma cells revealed significantly reduced proliferation, apoptosis resistance, migratory activity and matrix metalloproteinase 2 (MMP2) expression. In a syngeneic murine model of hepatic metastasis, GLUT1-suppressed cells formed significantly less metastases and showed increased apoptosis compared to metastases formed by control cells. Treatment of four different human melanoma cell lines with a pharmacological GLUT1 inhibitor caused a dose-dependent reduction of proliferation, apoptosis resistance, migratory activity and MMP2 expression. Analysis of MAPK signal pathways showed that GLUT1 inhibition significantly decreased JNK activation, which regulates a wide range of targets in the metastatic cascade. In summary, our study provides functional evidence that enhanced GLUT1 expression in melanoma cells favors their metastatic behavior. These findings specify GLUT1 as an attractive therapeutic target and prognostic marker for this highly aggressive tumor.