24 results on '"Müller, Stefan"'
Search Results
2. High-throughput proteomics fiber typing (ProFiT) for comprehensive characterization of single skeletal muscle fibers
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Kallabis, Sebastian, Abraham, Lena, Müller, Stefan, Dzialas, Verena, Türk, Clara, Wiederstein, Janica Lea, Bock, Theresa, Nolte, Hendrik, Nogara, Leonardo, Blaauw, Bert, Braun, Thomas, and Krüger, Marcus
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- 2020
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3. A matched-pair analysis on survival and response rates between German and non-German cancer patients treated at a Comprehensive Cancer Center
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Budde, Marie K., Kuhn, Walther, Keyver-Paik, Mignon-Denise, Bootz, Friedrich, Kalff, Jörg C., Müller, Stefan C., Bieber, Thomas, Brossart, Peter, Vatter, Hartmut, Herrlinger, Ulrich, Wirtz, Dieter C., Schild, Hans H., Kristiansen, Glen, Pietsch, Thorsten, Aretz, Stefan, Geiser, Franziska, Radbruch, Lukas, Reich, Rudolf H., Strassburg, Christian P., Skowasch, Dirk, Essler, Markus, Ernstmann, Nicole, Landsberg, Jennifer, Funke, Benjamin, and Schmidt-Wolf, Ingo G. H.
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- 2019
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4. How the introduction of OSCEs has affected the time students spend studying: results of a nationwide study
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Müller, Stefan, Koch, Ines, Settmacher, Utz, and Dahmen, Uta
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- 2019
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5. Fungaemia caused by obstructive renal candida bezoars leads to bilateral chorioretinitis: a case report
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Stein, Johannes, Latz, Stefan, Ellinger, Jörg, Fechner, Guido, Safi, Maher, Krausewitz, Philipp, Müller, Simone, Weyer, Karin, and Müller, Stefan C.
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- 2018
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6. Differential expression of Mediator complex subunit MED15 in testicular germ cell tumors
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Klümper, Niklas, Syring, Isabella, Offermann, Anne, Adler, David, Vogel, Wenzel, Müller, Stefan C., Ellinger, Jörg, Strauß, Arne, Radzun, Heinz Joachim, Ströbel, Philipp, Brägelmann, Johannes, Perner, Sven, and Bremmer, Felix
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- 2015
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7. Serum miR-122-5p and miR-206 expression: non-invasive prognostic biomarkers for renal cell carcinoma.
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Heinemann, Frauke G., Tolkach, Yuri, Deng, Mario, Schmidt, Doris, Perner, Sven, Kristiansen, Glen, Müller, Stefan C., and Ellinger, Jörg
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- 2018
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8. YRNA expression predicts survival in bladder cancer patients.
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Yuri Tolkach, Stahl, Anna Franziska, Niehoff, Eva-Maria, Zhao, Chenming, Kristiansen, Glen, Müller, Stefan Cajetan, Ellinger, Jörg, and Tolkach, Yuri
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BLADDER cancer genetics ,BLADDER cancer patients ,NON-coding RNA ,BLADDER cancer ,CARCINOGENESIS ,METASTASIS ,CANCER prognosis ,ANTIGENS ,BLADDER tumors ,CARRIER proteins ,GENES ,PROGNOSIS ,RNA ,TRANSITIONAL cell carcinoma ,KAPLAN-Meier estimator - Abstract
Background: Non-coding RNAs play an important role in human carcinogenesis. YRNAs (Ro-associated Y), a novel class of non-coding RNAs, have been identified as biomarker in various malignancies, but remain to be studied in urinary bladder cancer (BCA) patients.Methods: The expression of all four YRNAs (RNY1, RNY3, RNY4, RNY5) was determined in archival BCA (urothelial carcinoma, n = 88) and normal urothelial bladder (n = 30) tissues using quantitative real-time PCR. Associations with clinicopathological parameters and prognostic role for overall and cancer-specific survival were analysed.Results: All YRNAs were significantly downregulated in BCA tissue. A low expression of RNY1, RNY3 and RNY4 was associated with muscle-invasive BCA, lymph node metastases and advanced grade. Furthermore, expression of RNY1 and RNY3 was predictive for BCA patients' overall (also RNY4) and cancer-specific survival as estimated using Kaplan-Meier and univariate (but not multivariate) Cox regression analyses. RNY1, RNY3 and RNY4 show good discriminative ability between tumor and normal tissue, as well as between muscle-invasive and non-muscle-invasive urothelial carcinoma.Conclusions: The expression of YRNAs is altered in BCA and associated with poor prognosis. Possible diagnostic role of YRNAs should be investigated in further studies. [ABSTRACT FROM AUTHOR]- Published
- 2017
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9. Regulation of glucose uptake in lymphoma cell lines by c-MYC- and PI3K-dependent signaling pathways and impact of glycolytic pathways on cell viability.
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Bockisch, Andreas, Müller, Stefan, Broecker-Preuss, Martina, Becher-Boveleth, Nina, and Dührsen, Ulrich
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WARBURG Effect (Oncology) , *GLUCOSE metabolism , *LYMPHOMAS , *GLUCOSE oxidase , *POSITRON emission tomography , *RAPAMYCIN , *PROTEIN metabolism , *CELL lines , *CELL physiology , *DEOXY sugars , *GLYCOLYSIS , *HETEROCYCLIC compounds , *PHOSPHOTRANSFERASES , *RADIOPHARMACEUTICALS , *TIME , *CHROMONES , *PHARMACODYNAMICS - Abstract
Background: Changes in glucose and energy metabolism contribute to the altered phenotype of cancer cells and are the basis for positron emission tomography with 18F-fluoro-2-deoxy-D-glucose (FDG) to visualize tumors in vivo. The molecular background of the enhanced glucose uptake and its regulation in lymphoma cells is not fully clarified and may provide new possibilities to reverse the altered metabolism. Thus in this study we investigated regulation of glucose uptake by different signaling pathways. Furthermore, the effect of the glucose analog 2-deoxy-D-glucose (2-DG) alone and in combination with other inhibitors on cell survival was studied.Methods: An FDG uptake assay was established and uptake of FDG by lymphoma cells was determined after incubation with inhibitors of the c-MYC and the PI3K signalling pathways that are known to be activated in lymphoma cells and able to regulate glucose metabolism. Inhibitors of MAPK signalling pathways whose role in altered metabolism is still unclear were also investigated. Expression of mRNAs of the glucose transporter 1 (GLUT1), hexokinase 2 (HK2), glucose-6-phosphatase (G6Pase) and lactate dehydrogenase A (LDHA) and of the glucose metabolism-regulating micro RNAs (miRNA) miR21, -23a, -133a, -133b, -138-1 and -143 was determined by RT-PCR. Cell viability was analysed by MTT assay.Results: Treatment with the c-MYC inhibitor 10058-F4 and inhibitors of the PI3K/mTOR pathway diminished uptake of FDG in all three cell lines, while inhibition of MAPK pathways had no effect on glucose uptake. Expression of glycolysis-related genes and miRNAs were diminished, although to a variable degree in the three cell lines. The c-MYC inhibitor, the PI3K inhibitor LY294002, the mTOR inhibitor Rapamycin and 2-DG all diminished the number of viable cells. Interestingly, in combination with 2-DG, the c-MYC inhibitor, LY294002 and the p38 MAPK inhibitor SB203580 had synergistic effects on cell viability in all three cell lines.Conclusions: c-MYC- and PI3K/mTOR-inhibitors decreased viability of the lymphoma cells and led to decreased glucose uptake, expression of glycolysis-associated genes, and glucose metabolism-regulating miRNAs. Inhibition of HK by 2-DG reduced cell numbers as a single agent and synergistically with inhibitors of other intracellular pathways. Thus, targeted inhibition of the pathways investigated here could be a strategy to suppress the glycolytic phenotype of lymphoma cells and reduce proliferation. [ABSTRACT FROM AUTHOR]- Published
- 2017
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10. Flightless-I governs cell fate by recruiting the SUMO isopeptidase SENP3 to distinct HOX genes.
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Nayak, Arnab, Reck, Anja, Morsczeck, Christian, and Müller, Stefan
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CELL determination ,SMALL ubiquitin-related modifier proteins ,PEPTIDASE ,CHROMATIN ,HISTONE methyltransferases - Abstract
Background: Despite recent studies on the role of ubiquitin-related SUMO modifier in cell fate decisions, our understanding on precise molecular mechanisms of these processes is limited. Previously, we established that the SUMO isopeptidase SENP3 regulates chromatin assembly of the MLL1/2 histone methyltransferase complex at distinct HOX genes, including the osteogenic master regulator DLX3. A comprehensive mechanism that regulates SENP3 transcriptional function was not understood. Results: Here, we identified flightless-I homolog (FLII), a member of the gelsolin family of actin-remodeling proteins, as a novel regulator of SENP3. We demonstrate that FLII is associated with SENP3 and the MLL1/2 complex. We further show that FLII determines SENP3 recruitment and MLL1/2 complex assembly on the DLX3 gene. Consequently, FLII is indispensible for H3K4 methylation and proper loading of active RNA polymerase II at this gene locus. Most importantly, FLII-mediated SENP3 regulation governs osteogenic differentiation of human mesenchymal stem cells. Conclusion: Altogether, these data reveal a crucial functional interconnection of FLII with the sumoylation machinery that converges on epigenetic regulation and cell fate determination. [ABSTRACT FROM AUTHOR]
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- 2017
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11. The BH3 mimetic drug ABT-737 induces apoptosis and acts synergistically with chemotherapeutic drugs in thyroid carcinoma cells.
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Broecker-Preuss, Martina, Becher-Boveleth, Nina, Müller, Stefan, and Mann, Klaus
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APOPTOSIS ,IODINE isotopes ,CANCER chemotherapy ,ANAPLASTIC thyroid cancer ,THYROID cancer ,COLORIMETRIC analysis - Abstract
Background: Patients with dedifferentiated and anaplastic thyroid carcinomas that do not take up radioiodine are resistant to chemotherapeutic treatment and external irradiation and thus are difficult to treat. Direct induction of apoptosis is a promising approach in these apoptosis-resistant tumor cells. The BH3 mimetic ABT-737 belongs to a new class of drugs that target anti-apoptotic proteins of the BCL-2 family and facilitate cell death. The purpose of this study was to investigate the effect of ABT-737 alone or in combination with chemotherapeutic drugs on thyroid carcinoma cell lines. Methods: A total of 16 cell lines derived from follicular, papillary, and anaplastic thyroid carcinomas were treated with ABT-737. Cell viability was measured with MTT assay. Cell death was determined by cell cycle phase distribution and subG1 peak analyses, determination of caspase 3/7 activity and caspase cleavage products, lactate dehydrogenase (LDH) liberation assays and LC3 analysis by western blot. Results: The number of viable cells was decreased in all cell lines examined after ABT-737 treatment, with IC50 values ranging from 0.73 to 15.6 μM. Biochemical markers of apoptosis like caspase activities, caspase cleavage products and DNA fragmentation determined as SubG1 peak were elevated after ABT-737 treatment, but no LC3 cleavage was induced by ABT-737 indicating no autophagic processes. In combination with doxorubicin and gemcitabine, ABT-737 showed synergistic effects on cell viability. Conclusions: With these experiments we demonstrated the efficacy of the BH3 mimetic drug ABT-737 against dedifferentiated thyroid carcinoma cells of various histological origins and showed synergistic effects with chemotherapeutic drugs. ABT-737-treated cells underwent an apoptotic cell death. ABT-737 and related BH3 mimetic drugs, alone or in combination, may thus be of value as a new therapeutic option for dedifferentiated thyroid carcinomas. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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12. Identification of the dopamine transporter SLC6A3 as a biomarker for patients with renal cell carcinoma.
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Schrödter, Sarah, Braun, Martin, Syring, Isabella, Klümper, Niklas, Deng, Mario, Schmidt, Doris, Perner, Sven, Müller, Stefan C., and Ellinger, Jörg
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RENAL cell carcinoma ,DOPAMINE receptors ,CARRIER proteins ,MOLECULAR oncology ,MOLECULAR biology ,BIOMARKERS - Abstract
Background: Clear cell renal cell carcinoma (ccRCC) is among the most common human malignancies. Methods: In order to provide better understanding of the molecular biology of ccRCC and to identify potential diagnostic/prognostic biomarker and therapeutic targets, we utilized a microarray to profile mRNA expression of corresponding normal and malignant renal tissues. Real-time PCR, Western Blot and immunohistochemistry were applied to study the expression of candidate biomarkers. ccRCC cell lines were treated with sertraline to inhibit the dopamine transporter SLC6A3. Results: Differential expression of fourteen mRNAs, yet not studied in ccRCC in depth, was confirmed using qPCR (upregulation: SLC6A3, NPTX2, TNFAIP6, NDUFA4L2, ENPP3, FABP6, SPINK13; downregulation: FXYD4, SLC12A1, KNG1, NPHS2, SLC13A3, GCGR, PLG). Up-/downregulation was also confirmed for FXYD4, KNG1, NPTX2 and SLC12A1 by Western Blot on the protein level. In contrast to the mRNA expression, protein expression of the dopamine transporter SLC6A3 was lower in ccRCC compared to normal renal tissue. Immunohistochemistry indicated that this decrease was due to higher concentrations of SLC6A3 in the proximal tubules. Immunohistochemical analyses further demonstrated that high SLC6A3 expression in ccRCC tissue was correlated with a shorter period of recurrence-free survival following surgery. Treatment of ccRCC cells with the SLC6A3 inhibitor sertraline induced dose-dependent cell-death. Conclusion: Our study identified several novel biomarkers with diagnostic potential and further investigations on sertraline as therapeutic agent in ccRCC patients are warranted. [ABSTRACT FROM AUTHOR]
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- 2016
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13. Sorafenib inhibits intracellular signaling pathways and induces cell cycle arrest and cell death in thyroid carcinoma cells irrespective of histological origin or BRAF mutational status.
- Author
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Broecker-Preuss, Martina, Müller, Stefan, Britten, Martin, Worm, Karl, Schmid, Kurt Werner, Mann, Klaus, and Fuhrer, Dagmar
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THYROID cancer treatment , *THYROID cancer patients , *NICOTINAMIDE , *CELLULAR signal transduction , *CELL cycle , *CELL death , *GENETIC mutation , *THERAPEUTICS - Abstract
Background: Patients with dedifferentiated or anaplastic thyroid carcinomas currently lack appropriate treatment options. Kinase inhibitors are among the most promising new agents as alternative strategies. The BRAF- and multi-kinase inhibitor, sorafenib, has already shown antitumor effects in thyroid carcinoma patients in a phase III clinical trial. In this study we aim to better characterize molecular effects and efficacy of sorafenib against thyroid carcinoma cells with various histological origins and different BRAF mutational status. Analysis of different signaling pathways affected by sorafenib may contribute to assist a more specific therapy choice with fewer side effects. Twelve thyroid carcinoma cell lines derived from anaplastic, follicular and papillary thyroid carcinomas with wildtype or mutationally activated BRAF were treated with sorafenib. Growth inhibition, cell cycle arrest, cell death induction and inhibition of intracellular signaling pathways were then comprehensively analyzed. Methods: Cell viability was analyzed by MTT assay, and the cell cycle was assessed by flow cytometry after propidium iodide staining. Cell death was assessed by lactate dehydrogenase liberation assays, caspase activity assays and subG1 peak determinations. Inhibition of intracellular pathways was analyzed in dot blot and western blot analyses. Results: Sorafenib inhibited proliferation of all thyroid carcinoma cell lines tested with IC50 values ranging between 1.85 and 4.2 µM. Cells derived from papillary carcinoma harboring the mutant BRAFV600E allele were slightly more sensitive to sorafenib than those harboring wildtype BRAF. Cell cycle analyses and caspase assays showed a sorafenib-dependent induction of apoptosis in all cell lines, whereas increased lactate dehydrogenase release suggested cell membrane disruption. Sorafenib treatment caused a rapid inhibition of various MAP kinases in addition to inhibiting AKT and receptor tyrosine kinases. Conclusions: Sorafenib inhibited multiple intracellular signaling pathways in thyroid carcinoma cells, which resulted in cell cycle arrest and the initiation of apoptosis. Sorafenib was effective against all thyroid carcinoma cell lines regardless of their tumor subtype origin or BRAF status, confirming that sorafenib is therapeutically beneficial for patients with any subtype of dedifferentiated thyroid cancer. Inhibition of single intracellular targets of sorafenib in thyroid carcinoma cells may allow the development of more specific therapeutic intervention with less side effects. [ABSTRACT FROM AUTHOR]
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- 2015
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14. Identification of novel long non-coding RNAs in clear cell renal cell carcinoma.
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Blondeau, Jasmine J. C., Deng, Mario, Syring, Isabella, Schrödter, Sarah, Schmidt, Doris, Perner, Sven, Müller, Stefan C., and Ellinger, Jörg
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- 2015
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15. SUMO-specific proteases/isopeptidases: SENPs and beyond
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Nayak, Arnab and Müller, Stefan
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- 2014
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16. Distinct nuclear orientation patterns for mouse chromosome 11 in normal B lymphocytes.
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Schmälter, Ann-Kristin, Kuzyk, Alexandra, Righolt, Christiaan H., Neusser, Michaela, Steinlein, Ortrud K., Müller, Stefan, and Mai, Sabine
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CHROMOSOMES ,CELL nuclei ,FLUORESCENCE in situ hybridization ,B cells ,ANIMAL models in research - Abstract
Background Characterizing the nuclear orientation of chromosomes in the three-dimensional (3D) nucleus by multicolor banding (mBANDing) is a new approach towards understanding nuclear organization of chromosome territories. An mBANDing paint is composed of multiple overlapping subchromosomal probes that represent different regions of a single chromosome. In this study, we used it for the analysis of chromosome orientation in 3D interphase nuclei. We determined whether the nuclear orientation of the two chromosome 11 homologs was random or preferential, and if it was conserved between diploid mouse Pre B lymphocytes of BALB/c origin and primary B lymphocytes of congenic [T38HxBALB/c]N wild-type mice. The chromosome orientation was assessed visually and through a semi-automated quantitative analysis of the radial and angular orientation patterns observed in both B cell types. Results Our data indicate that there are different preferential patterns of chromosome 11 orientation, which are shared between both mouse cell types (p > 0.05). In the most common case for both cell types, both copies of chromosome 11 were oriented in parallel with the nuclear border. The second most common pattern in both types of B lymphocytes was with one homolog of chromosome 11 positioned with its telomeric end towards the nuclear center and with its centromeric end towards the periphery, while the other chromosome 11 was found parallel with the nuclear border. In addition to these two most common orientations present in approximately 50% of nuclei from each cell type, other orientations were observed at lower frequencies. Conclusions We conclude that there are probabilistic, non-random orientation patterns for mouse chromosome 11 in the mouse B lymphocytes we investigated (p < 0.0001). [ABSTRACT FROM AUTHOR]
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- 2014
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17. Evolutionary genomic remodelling of the human 4q subtelomere (4q35.2).
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Bodega, Beatrice, Cardone, Maria Francesca, Müller, Stefan, Neusser, Michaela, Orzan, Francesca, Rossi, Elena, Battaglioli, Elena, Marozzi, Anna, Riva, Paola, Rocchi, Mariano, Meneveri, Raffaella, and Ginelli, Enrico
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TELOMERES ,GENOMICS ,BIOLOGICAL evolution ,CHROMATIN ,GENETIC regulation - Abstract
Background: In order to obtain insights into the functionality of the human 4q35.2 domain harbouring the facioscapulohumeral muscular dystrophy (FSHD) locus, we investigated in African apes genomic and chromatin organisations, and the nuclear topology of orthologous regions. Results: A basic block consisting of short D4Z4 arrays (10-15 repeats), 4q35.2 specific sequences, and approximately 35 kb of interspersed repeats from different LINE subfamilies was repeated at least twice in the gorilla 4qter. This genomic organisation has undergone evolutionary remodelling, leading to the single representation of both the D4Z4 array and LINE block in chimpanzee, and the loss of the LINE block in humans. The genomic remodelling has had an impact on 4qter chromatin organisation, but not its interphase nuclear topology. In comparison with humans, African apes show very low or undetectable levels of FRG1 and FRG2 histone 4 acetylation and gene transcription, although histone deacetylase inhibition restores gene transcription to levels comparable with those of human cells, thus indicating that the 4qter region is capable of acquiring a more open chromatin structure. Conversely, as in humans, the 4qter region in African apes has a very peripheral nuclear localisation. Conclusion: The 4q subtelomere has undergone substantial genomic changes during evolution that have had an impact on chromatin condensation and the region's transcriptional regulation. Consequently, the 4qter genes in African apes and humans seem to be subjected to a different strategy of regulation in which LINE and D4Z4 sequences may play a pivotal role. However, the effect of peripheral nuclear anchoring of 4qter on these regulation mechanisms is still unclear. The observed differences in the regulation of 4qter gene expression between African apes and humans suggest that the human 4q35.2 locus has acquired a novel functional relevance. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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18. The influence of blood on the efficacy of intraperitoneally applied phospholipids for prevention of adhesions.
- Author
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Butz, Nick, Müller, Stefan A., Treutner, Karl-Heinz, Anurov, Michail, Titkova, Svetlana, Oettinger, Alexander P., and Schumpelick, Volker
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TISSUE adhesions ,PHOSPHOLIPIDS ,SURGICAL complications ,MEDICAL research ,LABORATORY rabbits ,PREVENTION - Abstract
Background: The formation of adhesions following abdominal surgery is a well known problem. In previous studies we demonstrated the efficacy and safety of intraperitoneally applied phospholipids in order to prevent adhesion formation. This study evaluates the influence of blood on the efficacy of intraperitoneally applied phospholipids for prevention of adhesions. Methods: In 40 Chinchilla rabbits adhesions were induced by median laparotomy, standardized abrasion of the visceral and parietal peritoneum in defined areas of the ventral abdominal wall and the caecum. The animals were randomly divided into four groups. They received either phospholipids 3.0% or normal saline (NaCl 0,9%) (5 ml/kg body weight). In 50% of the rabbits we simulated intraperitoneal bleeding by administration of blood (1,5 ml/kg body weight). The other half served as control group. Ten days following the operation the animals were sacrificed and adhesion formation was assessed by computer aided planimetry and histopathologic examination. Results: The median adhesion surface area in the NaCl-group (n = 9) amounted to 68,72 mm2, in the NaCl+Blood-group (n = 10) 147,68 mm2. In the Phospholipid (PhL)-group (n = 9) the median adhesion surface area measured 9,35 mm2, in the PhL+Blood-group (n = 9) 11,95 mm2. The phospholipid groups had a significantly smaller adhesion surface area (p < 0.05). Conclusion: Again these results confirm the efficacy of phospholipids in the prevention of adhesions in comparison to NaCl (p = 0,04). We also demonstrated the adhesion preventing effect of phospholipids in the presence of intraperitoneal blood. [ABSTRACT FROM AUTHOR]
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- 2007
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19. Identification of prostaglandin receptors in human ureters.
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Oll, Matthias, Baumann, Claudia, Behbahani, Turang E, Ruecker, Alexander von, Müller, Stefan C, Ellinger, Jörg, and von Ruecker, Alexander
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Background: Prostaglandins play an important role in ureteral obstruction, but the detailed expression profiles of the prostaglandin receptors (PTGER1, PTGER2, PTGER3, PTGER4, PTGFR) remain unknown in the different parts of the human ureter.Methods: The expression pattern of PTGER1, PTGER2, PTGER3, PTGER4 and PTGFR was determined in human distal, mid and proximal ureter and renal pelvis samples using immunohistochemistry (protein levels) and quantitative real-time PCR (mRNA).Results: PTGER1 was highly expressed in most samples irrespective of the ureteral localization; however, urothelial cells had higher levels of PTGER1 than smooth muscle cells. PTGFR was also moderately to strongly expressed in urothelial and smooth muscle cells. In comparison, PTGER2-4 expression was mostly unexpressed or weakly expressed in urothelial and smooth cells in all regions.Conclusions: Our data indicate high levels of PTGER1 in ureters. [ABSTRACT FROM AUTHOR]- Published
- 2012
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20. What makes a reaction network "chemical"?
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Müller S, Flamm C, and Stadler PF
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Background: Reaction networks (RNs) comprise a set X of species and a set [Formula: see text] of reactions [Formula: see text], each converting a multiset of educts [Formula: see text] into a multiset [Formula: see text] of products. RNs are equivalent to directed hypergraphs. However, not all RNs necessarily admit a chemical interpretation. Instead, they might contradict fundamental principles of physics such as the conservation of energy and mass or the reversibility of chemical reactions. The consequences of these necessary conditions for the stoichiometric matrix [Formula: see text] have been discussed extensively in the chemical literature. Here, we provide sufficient conditions for [Formula: see text] that guarantee the interpretation of RNs in terms of balanced sum formulas and structural formulas, respectively., Results: Chemically plausible RNs allow neither a perpetuum mobile, i.e., a "futile cycle" of reactions with non-vanishing energy production, nor the creation or annihilation of mass. Such RNs are said to be thermodynamically sound and conservative. For finite RNs, both conditions can be expressed equivalently as properties of the stoichiometric matrix [Formula: see text]. The first condition is vacuous for reversible networks, but it excludes irreversible futile cycles and-in a stricter sense-futile cycles that even contain an irreversible reaction. The second condition is equivalent to the existence of a strictly positive reaction invariant. It is also sufficient for the existence of a realization in terms of sum formulas, obeying conservation of "atoms". In particular, these realizations can be chosen such that any two species have distinct sum formulas, unless [Formula: see text] implies that they are "obligatory isomers". In terms of structural formulas, every compound is a labeled multigraph, in essence a Lewis formula, and reactions comprise only a rearrangement of bonds such that the total bond order is preserved. In particular, for every conservative RN, there exists a Lewis realization, in which any two compounds are realized by pairwisely distinct multigraphs. Finally, we show that, in general, there are infinitely many realizations for a given conservative RN., Conclusions: "Chemical" RNs are directed hypergraphs with a stoichiometric matrix [Formula: see text] whose left kernel contains a strictly positive vector and whose right kernel does not contain a futile cycle involving an irreversible reaction. This simple characterization also provides a concise specification of random models for chemical RNs that additionally constrain [Formula: see text] by rank, sparsity, or distribution of the non-zero entries. Furthermore, it suggests several interesting avenues for future research, in particular, concerning alternative representations of reaction networks and infinite chemical universes., (© 2022. The Author(s).)
- Published
- 2022
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21. YRNA expression predicts survival in bladder cancer patients.
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Tolkach Y, Stahl AF, Niehoff EM, Zhao C, Kristiansen G, Müller SC, and Ellinger J
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- Adult, Aged, Aged, 80 and over, Carcinoma, Transitional Cell, Female, Gene Expression Regulation, Neoplastic, Humans, Kaplan-Meier Estimate, Lymphatic Metastasis pathology, Male, Middle Aged, Prognosis, Urinary Bladder Neoplasms pathology, Autoantigens genetics, Biomarkers, Tumor genetics, Lymphatic Metastasis genetics, RNA, Small Cytoplasmic genetics, Ribonucleoproteins genetics, Urinary Bladder Neoplasms genetics
- Abstract
Background: Non-coding RNAs play an important role in human carcinogenesis. YRNAs (Ro-associated Y), a novel class of non-coding RNAs, have been identified as biomarker in various malignancies, but remain to be studied in urinary bladder cancer (BCA) patients., Methods: The expression of all four YRNAs (RNY1, RNY3, RNY4, RNY5) was determined in archival BCA (urothelial carcinoma, n = 88) and normal urothelial bladder (n = 30) tissues using quantitative real-time PCR. Associations with clinicopathological parameters and prognostic role for overall and cancer-specific survival were analysed., Results: All YRNAs were significantly downregulated in BCA tissue. A low expression of RNY1, RNY3 and RNY4 was associated with muscle-invasive BCA, lymph node metastases and advanced grade. Furthermore, expression of RNY1 and RNY3 was predictive for BCA patients' overall (also RNY4) and cancer-specific survival as estimated using Kaplan-Meier and univariate (but not multivariate) Cox regression analyses. RNY1, RNY3 and RNY4 show good discriminative ability between tumor and normal tissue, as well as between muscle-invasive and non-muscle-invasive urothelial carcinoma., Conclusions: The expression of YRNAs is altered in BCA and associated with poor prognosis. Possible diagnostic role of YRNAs should be investigated in further studies.
- Published
- 2017
- Full Text
- View/download PDF
22. Regulation of glucose uptake in lymphoma cell lines by c-MYC- and PI3K-dependent signaling pathways and impact of glycolytic pathways on cell viability.
- Author
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Broecker-Preuss M, Becher-Boveleth N, Bockisch A, Dührsen U, and Müller S
- Subjects
- Cell Line, Tumor, Cell Survival drug effects, Chromones pharmacology, Fluorodeoxyglucose F18 metabolism, Humans, Inhibitory Concentration 50, Morpholines pharmacology, Sirolimus pharmacology, Time Factors, Glucose metabolism, Glycolysis drug effects, Lymphoma metabolism, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins c-myc metabolism
- Abstract
Background: Changes in glucose and energy metabolism contribute to the altered phenotype of cancer cells and are the basis for positron emission tomography with
18 F-fluoro-2-deoxy-D-glucose (FDG) to visualize tumors in vivo. The molecular background of the enhanced glucose uptake and its regulation in lymphoma cells is not fully clarified and may provide new possibilities to reverse the altered metabolism. Thus in this study we investigated regulation of glucose uptake by different signaling pathways. Furthermore, the effect of the glucose analog 2-deoxy-D-glucose (2-DG) alone and in combination with other inhibitors on cell survival was studied., Methods: An FDG uptake assay was established and uptake of FDG by lymphoma cells was determined after incubation with inhibitors of the c-MYC and the PI3K signalling pathways that are known to be activated in lymphoma cells and able to regulate glucose metabolism. Inhibitors of MAPK signalling pathways whose role in altered metabolism is still unclear were also investigated. Expression of mRNAs of the glucose transporter 1 (GLUT1), hexokinase 2 (HK2), glucose-6-phosphatase (G6Pase) and lactate dehydrogenase A (LDHA) and of the glucose metabolism-regulating micro RNAs (miRNA) miR21, -23a, -133a, -133b, -138-1 and -143 was determined by RT-PCR. Cell viability was analysed by MTT assay., Results: Treatment with the c-MYC inhibitor 10058-F4 and inhibitors of the PI3K/mTOR pathway diminished uptake of FDG in all three cell lines, while inhibition of MAPK pathways had no effect on glucose uptake. Expression of glycolysis-related genes and miRNAs were diminished, although to a variable degree in the three cell lines. The c-MYC inhibitor, the PI3K inhibitor LY294002, the mTOR inhibitor Rapamycin and 2-DG all diminished the number of viable cells. Interestingly, in combination with 2-DG, the c-MYC inhibitor, LY294002 and the p38 MAPK inhibitor SB203580 had synergistic effects on cell viability in all three cell lines., Conclusions: c-MYC- and PI3K/mTOR-inhibitors decreased viability of the lymphoma cells and led to decreased glucose uptake, expression of glycolysis-associated genes, and glucose metabolism-regulating miRNAs. Inhibition of HK by 2-DG reduced cell numbers as a single agent and synergistically with inhibitors of other intracellular pathways. Thus, targeted inhibition of the pathways investigated here could be a strategy to suppress the glycolytic phenotype of lymphoma cells and reduce proliferation.- Published
- 2017
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- View/download PDF
23. Alterations of global histone H4K20 methylation during prostate carcinogenesis.
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Behbahani TE, Kahl P, von der Gathen J, Heukamp LC, Baumann C, Gütgemann I, Walter B, Hofstädter F, Bastian PJ, von Ruecker A, Müller SC, Rogenhofer S, and Ellinger J
- Subjects
- DNA Methylation, Humans, Male, Mutation genetics, Cell Transformation, Neoplastic genetics, Gene Expression Regulation, Neoplastic, Histones genetics, Prostatic Neoplasms genetics
- Abstract
Background: Global histone modifications have been implicated in the progression of various tumour entities. Our study was designed to assess global methylation levels of histone 4 lysine 20 (H4K20me1-3) at different stages of prostate cancer (PCA) carcinogenesis., Methods: Global H4K20 methylation levels were evaluated using a tissue microarray in patients with clinically localized PCA (n = 113), non-malignant prostate disease (n = 27), metastatic hormone-naive PCA (mPCA, n = 30) and castration-resistant PCA (CRPC, n = 34). Immunohistochemistry was performed to assess global levels of H4K20 methylation levels., Results: Similar proportions of the normal, PCA, and mPCA prostate tissues showed strong H4K20me3 staining. CRPC tissue analysis showed the weakest immunostaining levels of H4K20me1 and H4K20me2, compared to other prostate tissues. H4K20me2 methylation levels indicated significant differences in examined tissues except for normal prostate versus PCA tissue. H4K20me1 differentiates CRPC from other prostate tissues. H4K20me1 was significantly correlated with lymph node metastases, and H4K20me2 showed a significant correlation with the Gleason score. However, H4K20 methylation levels failed to predict PSA recurrence after radical prostatectomy., Conclusions: H4K20 methylation levels constitute valuable markers for the dynamic process of prostate cancer carcinogenesis.
- Published
- 2012
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24. Reconstruction of cellular variability from spatiotemporal patterns of Dictyostelium discoideum.
- Author
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Hilgardt C, Müller SC, and Hütt MT
- Abstract
Variability in cell properties can be an important driving mechanism behind spatiotemporal patterns in biological systems, as the degree of cell-to-cell differences determines the capacity of cells to locally synchronize and, consequently, form patterns on a larger spatial scale. In principle, certain features of spatial patterns emerging with time may be regulated by variability or, more specifically, by certain constellations of cell-to-cell differences. Similarly, measuring variability in a system (i.e. the spatial distribution of cell-cell differences) may help predict properties of later-stage patterns.Here we apply and compare different statistical methods of extracting such systematic cell-to-cell differences in the case of patterns generated with a simple model system of an excitable medium and of experimental data by the slime mold Dictyostelium discoideum. We demonstrate with the help of a correlation analysis that these methods produce systematic (i.e. stationary) results for cell properties. Furthermore, we discuss possible applications of our method, in particular how these cell properties may serve as predictors of certain later-stage patterns.
- Published
- 2007
- Full Text
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