@article{BartelPeinPopperetal.2019, author = {Bartel, Karin and Pein, Helmut and Popper, Bastian and Schmitt, Sabine and Janaki-Raman, Sudha and Schulze, Almut and Lengauer, Florian and Koeberle, Andreas and Werz, Oliver and Zischka, Hans and M{\"u}ller, Rolf and Vollmar, Angelika M. and Schwarzenberg, Karin von}, title = {Connecting lysosomes and mitochondria - a novel role for lipid metabolism in cancer cell death}, series = {Cell Communication and Signaling}, volume = {17}, journal = {Cell Communication and Signaling}, doi = {10.1186/s12964-019-0399-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221524}, year = {2019}, abstract = {Background The understanding of lysosomes has been expanded in recent research way beyond their view as cellular trash can. Lysosomes are pivotal in regulating metabolism, endocytosis and autophagy and are implicated in cancer. Recently it was discovered that the lysosomal V-ATPase, which is known to induce apoptosis, interferes with lipid metabolism in cancer, yet the interplay between these organelles is poorly understood. Methods LC-MS/MS analysis was performed to investigate lipid distribution in cells. Cell survival and signaling pathways were analyzed by means of cell biological methods (qPCR, Western Blot, flow cytometry, CellTiter-Blue). Mitochondrial structure was analyzed by confocal imaging and electron microscopy, their function was determined by flow cytometry and seahorse measurements. Results Our data reveal that interfering with lysosomal function changes composition and subcellular localization of triacylglycerids accompanied by an upregulation of PGC1α and PPARα expression, master regulators of energy and lipid metabolism. Furthermore, cardiolipin content is reduced driving mitochondria into fission, accompanied by a loss of membrane potential and reduction in oxidative capacity, which leads to a deregulation in cellular ROS and induction of mitochondria-driven apoptosis. Additionally, cells undergo a metabolic shift to glutamine dependency, correlated with the fission phenotype and sensitivity to lysosomal inhibition, most prominent in Ras mutated cells. Conclusion This study sheds mechanistic light on a largely uninvestigated triangle between lysosomes, lipid metabolism and mitochondrial function. Insight into this organelle crosstalk increases our understanding of mitochondria-driven cell death. Our findings furthermore provide a first hint on a connection of Ras pathway mutations and sensitivity towards lysosomal inhibitors.}, language = {en} } @article{GrebinykPrylutskaGrebinyketal.2019, author = {Grebinyk, Anna and Prylutska, Svitlana and Grebinyk, Sergii and Prylutskyy, Yuriy and Ritter, Uwe and Matyshevska, Olga and Dandekar, Thomas and Frohme, Marcus}, title = {Complexation with C\(_{60}\) fullerene increases doxorubicin efficiency against leukemic cells in vitro}, series = {Nanoscale Research Letters}, volume = {14}, journal = {Nanoscale Research Letters}, number = {61}, doi = {10.1186/s11671-019-2894-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228257}, year = {2019}, abstract = {Conventional anticancer chemotherapy is limited because of severe side effects as well as a quickly evolving multidrug resistance of the tumor cells. To address this problem, we have explored a C\(_{60}\) fullerene-based nanosized system as a carrier for anticancer drugs for an optimized drug delivery to leukemic cells.Here, we studied the physicochemical properties and anticancer activity of C\(_{60}\) fullerene noncovalent complexes with the commonly used anticancer drug doxorubicin. C\(_{60}\)-Doxorubicin complexes in a ratio 1:1 and 2:1 were characterized with UV/Vis spectrometry, dynamic light scattering, and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The obtained analytical data indicated that the 140-nm complexes were stable and could be used for biological applications. In leukemic cell lines (CCRF-CEM, Jurkat, THP1 and Molt-16), the nanocomplexes revealed 3.5 higher cytotoxic potential in comparison with the free drug in a range of nanomolar concentrations. Also, the intracellular drug's level evidenced C\(_{60}\) fullerene considerable nanocarrier function.The results of this study indicated that C\(_{60}\) fullerene-based delivery nanocomplexes had a potential value for optimization of doxorubicin efficiency against leukemic cells.}, language = {en} } @article{HeydarianYangSchweinlinetal.2019, author = {Heydarian, Motaharehsadat and Yang, Tao and Schweinlin, Matthias and Steinke, Maria and Walles, Heike and Rudel, Thomas and Kozjak-Pavlovic, Vera}, title = {Biomimetic human tissue model for long-term study of Neisseria gonorrhoeae infection}, series = {Frontiers in Microbiology}, volume = {10}, journal = {Frontiers in Microbiology}, number = {1740}, issn = {1664-302X}, doi = {10.3389/fmicb.2019.01740}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197912}, year = {2019}, abstract = {Gonorrhea is the second most common sexually transmitted infection in the world and is caused by Gram-negative diplococcus Neisseria gonorrhoeae. Since N. gonorrhoeae is a human-specific pathogen, animal infection models are only of limited use. Therefore, a suitable in vitro cell culture model for studying the complete infection including adhesion, transmigration and transport to deeper tissue layers is required. In the present study, we generated three independent 3D tissue models based on porcine small intestinal submucosa (SIS) scaffold by co-culturing human dermal fibroblasts with human colorectal carcinoma, endometrial epithelial, and male uroepithelial cells. Functional analyses such as transepithelial electrical resistance (TEER) and FITC-dextran assay indicated the high barrier integrity of the created monolayer. The histological, immunohistochemical, and ultra-structural analyses showed that the 3D SIS scaffold-based models closely mimic the main characteristics of the site of gonococcal infection in human host including the epithelial monolayer, the underlying connective tissue, mucus production, tight junction, and microvilli formation. We infected the established 3D tissue models with different N. gonorrhoeae strains and derivatives presenting various phenotypes regarding adhesion and invasion. The results indicated that the disruption of tight junctions and increase in interleukin production in response to the infection is strain and cell type-dependent. In addition, the models supported bacterial survival and proved to be better suitable for studying infection over the course of several days in comparison to commonly used Transwell® models. This was primarily due to increased resilience of the SIS scaffold models to infection in terms of changes in permeability, cell destruction and bacterial transmigration. In summary, the SIS scaffold-based 3D tissue models of human mucosal tissues represent promising tools for investigating N. gonorrhoeae infections under close-to-natural conditions.}, language = {en} } @article{GrebinykPrylutskaChepurnaetal.2019, author = {Grebinyk, Anna and Prylutska, Svitlana and Chepurna, Oksana and Grebinyk, Sergii and Prylutskyy, Yuriy and Ritter, Uwe and Ohulchanskyy, Tymish Y. and Matyshevska, Olga and Dandekar, Thomas and Frohme, Marcus}, title = {Synergy of chemo- and photodynamic therapies with C\(_{60}\) Fullerene-Doxorubicin nanocomplex}, series = {Nanomaterials}, volume = {9}, journal = {Nanomaterials}, number = {11}, issn = {2079-4991}, doi = {10.3390/nano9111540}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193140}, year = {2019}, abstract = {A nanosized drug complex was explored to improve the efficiency of cancer chemotherapy, complementing it with nanodelivery and photodynamic therapy. For this, nanomolar amounts of a non-covalent nanocomplex of Doxorubicin (Dox) with carbon nanoparticle C\(_{60}\) fullerene (C\(_{60}\)) were applied in 1:1 and 2:1 molar ratio, exploiting C\(_{60}\) both as a drug-carrier and as a photosensitizer. The fluorescence microscopy analysis of human leukemic CCRF-CEM cells, in vitro cancer model, treated with nanocomplexes showed Dox's nuclear and C\(_{60}\)'s extranuclear localization. It gave an opportunity to realize a double hit strategy against cancer cells based on Dox's antiproliferative activity and C\(_{60}\)'s photoinduced pro-oxidant activity. When cells were treated with 2:1 C\(_{60}\)-Dox and irradiated at 405 nm the high cytotoxicity of photo-irradiated C\(_{60}\)-Dox enabled a nanomolar concentration of Dox and C\(_{60}\) to efficiently kill cancer cells in vitro. The high pro-oxidant and pro-apoptotic efficiency decreased IC\(_{50}\) 16, 9 and 7 × 10\(^3\)-fold, if compared with the action of Dox, non-irradiated nanocomplex, and C\(_{60}\)'s photodynamic effect, correspondingly. Hereafter, a strong synergy of therapy arising from the combination of C\(_{60}\)-mediated Dox delivery and C\(_{60}\) photoexcitation was revealed. Our data indicate that a combination of chemo- and photodynamic therapies with C\(_{60}\)-Dox nanoformulation provides a promising synergetic approach for cancer treatment.}, language = {en} } @article{VillalobosWieseImhoffetal.2019, author = {Villalobos, Alvaro S. and Wiese, Jutta and Imhoff, Johannes F. and Dorador, Cristina and Keller, Alexander and Hentschel, Ute}, title = {Systematic affiliation and genome analysis of Subtercola vilae DB165T with particular emphasis on cold adaptation of an isolate from a high-altitude cold volcano lake}, series = {Microorganisms}, volume = {7}, journal = {Microorganisms}, number = {4}, issn = {2076-2607}, doi = {10.3390/microorganisms7040107}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197394}, year = {2019}, abstract = {Among the Microbacteriaceae the species of Subtercola and Agreia form closely associated clusters. Phylogenetic analysis demonstrated three major phylogenetic branches of these species. One of these branches contains the two psychrophilic species Subtercola frigoramans and Subtercola vilae, together with a larger number of isolates from various cold environments. Genomic evidence supports the separation of Agreia and Subtercola species. In order to gain insight into the ability of S. vilae to adapt to life in this extreme environment, we analyzed the genome with a particular focus on properties related to possible adaptation to a cold environment. General properties of the genome are presented, including carbon and energy metabolism, as well as secondary metabolite production. The repertoire of genes in the genome of S. vilae DB165\(^T\) linked to adaptations to the harsh conditions found in Llullaillaco Volcano Lake includes several mechanisms to transcribe proteins under low temperatures, such as a high number of tRNAs and cold shock proteins. In addition, S. vilae DB165\(^T\) is capable of producing a number of proteins to cope with oxidative stress, which is of particular relevance at low temperature environments, in which reactive oxygen species are more abundant. Most important, it obtains capacities to produce cryo-protectants, and to combat against ice crystal formation, it produces ice-binding proteins. Two new ice-binding proteins were identified which are unique to S. vilae DB165\(^T\). These results indicate that S. vilae has the capacity to employ different mechanisms to live under the extreme and cold conditions prevalent in Llullaillaco Volcano Lake.}, language = {en} } @article{LiuKinoshitaAdolfietal.2019, author = {Liu, Ruiqi and Kinoshita, Masato and Adolfi, Mateus C. and Schartl, Manfred}, title = {Analysis of the role of the Mc4r system in development, growth, and puberty of medaka}, series = {Frontiers in Endocrinology}, volume = {10}, journal = {Frontiers in Endocrinology}, doi = {10.3389/fendo.2019.00213}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201472}, pages = {213}, year = {2019}, abstract = {In mammals the melanocortin 4 receptor (Mc4r) signaling system has been mainly associated with the regulation of appetite and energy homeostasis. In fish of the genus Xiphophorus (platyfish and swordtails) puberty onset is genetically determined by a single locus, which encodes the mc4r. Wild populations of Xiphophorus are polymorphic for early and late-maturing individuals. Copy number variation of different mc4r alleles is responsible for the difference in puberty onset. To answer whether this is a special adaptation of the Mc4r signaling system in the lineage of Xiphophorus or a more widely conserved mechanism in teleosts, we studied the role of Mc4r in reproductive biology of medaka (Oryzias latipes), a close relative to Xiphophorus and a well-established model to study gonadal development. To understand the potential role of Mc4r in medaka, we characterized the major features of the Mc4r signaling system (mc4r, mrap2, pomc, agrp1). In medaka, all these genes are expressed before hatching. In adults, they are mainly expressed in the brain. The transcript of the receptor accessory protein mrap2 co-localizes with mc4r in the hypothalamus in adult brains indicating a conserved function of modulating Mc4r signaling. Comparing growth and puberty between wild-type and mc4r knockout medaka revealed that absence of Mc4r does not change puberty timing but significantly delays hatching. Embryonic development of knockout animals is retarded compared to wild-types. In conclusion, the Mc4r system in medaka is involved in regulation of growth rather than puberty.}, language = {en} } @article{YangRajeeveRudeletal.2019, author = {Yang, Manli and Rajeeve, Karthika and Rudel, Thomas and Dandekar, Thomas}, title = {Comprehensive Flux Modeling of Chlamydia trachomatis Proteome and qRT-PCR Data Indicate Biphasic Metabolic Differences Between Elementary Bodies and Reticulate Bodies During Infection}, series = {Frontiers in Microbiology}, volume = {10}, journal = {Frontiers in Microbiology}, number = {2350}, issn = {1664-302X}, doi = {10.3389/fmicb.2019.02350}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189434}, year = {2019}, abstract = {Metabolic adaptation to the host cell is important for obligate intracellular pathogens such as Chlamydia trachomatis (Ct). Here we infer the flux differences for Ct from proteome and qRT-PCR data by comprehensive pathway modeling. We compare the comparatively inert infectious elementary body (EB) and the active replicative reticulate body (RB) systematically using a genome-scale metabolic model with 321 metabolites and 277 reactions. This did yield 84 extreme pathways based on a published proteomics dataset at three different time points of infection. Validation of predictions was done by quantitative RT-PCR of enzyme mRNA expression at three time points. Ct's major active pathways are glycolysis, gluconeogenesis, glycerol-phospholipid (GPL) biosynthesis (support from host acetyl-CoA) and pentose phosphate pathway (PPP), while its incomplete TCA and fatty acid biosynthesis are less active. The modeled metabolic pathways are much more active in RB than in EB. Our in silico model suggests that EB and RB utilize folate to generate NAD(P)H using independent pathways. The only low metabolic flux inferred for EB involves mainly carbohydrate metabolism. RB utilizes energy -rich compounds to generate ATP in nucleic acid metabolism. Validation data for the modeling include proteomics experiments (model basis) as well as qRT-PCR confirmation of selected metabolic enzyme mRNA expression differences. The metabolic modeling is made fully available here. Its detailed insights and models on Ct metabolic adaptations during infection are a useful modeling basis for future studies.}, language = {en} } @article{DoerkPeterlongoMannermaaetal.2019, author = {D{\"o}rk, Thilo and Peterlongo, Peter and Mannermaa, Arto and Bolla, Manjeet K. and Wang, Qin and Dennis, Joe and Ahearn, Thomas and Andrulis, Irene L. and Anton-Culver, Hoda and Arndt, Volker and Aronson, Kristan J. and Augustinsson, Annelie and Beane Freeman, Laura E. and Beckmann, Matthias W. and Beeghly-Fadiel, Alicia and Behrens, Sabine and Bermisheva, Marina and Blomqvist, Carl and Bogdanova, Natalia V. and Bojesen, Stig E. and Brauch, Hiltrud and Brenner, Hermann and Burwinkel, Barbara and Canzian, Federico and Chan, Tsun L. and Chang-Claude, Jenny and Chanock, Stephen J. and Choi, Ji-Yeob and Christiansen, Hans and Clarke, Christine L. and Couch, Fergus J. and Czene, Kamila and Daly, Mary B. and dos-Santos-Silva, Isabel and Dwek, Miriam and Eccles, Diana M. and Ekici, Arif B. and Eriksson, Mikael and Evans, D. Gareth and Fasching, Peter A. and Figueroa, Jonine and Flyger, Henrik and Fritschi, Lin and Gabrielson, Marike and Gago-Dominguez, Manuela and Gao, Chi and Gapstur, Susan M. and Garc{\´i}a-Closas, Montserrat and Garc{\´i}a-S{\´a}enz, Jos{\´e} A. and Gaudet, Mia M. and Giles, Graham G. and Goldberg, Mark S. and Goldgar, David E. and Guen{\´e}l, Pascal and Haeberle, Lothar and Haimann, Christopher A. and H{\aa}kansson, Niclas and Hall, Per and Hamann, Ute and Hartman, Mikael and Hauke, Jan and Hein, Alexander and Hillemanns, Peter and Hogervorst, Frans B. L. and Hooning, Maartje J. and Hopper, John L. and Howell, Tony and Huo, Dezheng and Ito, Hidemi and Iwasaki, Motoki and Jakubowska, Anna and Janni, Wolfgang and John, Esther M. and Jung, Audrey and Kaaks, Rudolf and Kang, Daehee and Kapoor, Pooja Middha and Khusnutdinova, Elza and Kim, Sung-Won and Kitahara, Cari M. and Koutros, Stella and Kraft, Peter and Kristensen, Vessela N. and Kwong, Ava and Lambrechts, Diether and Le Marchand, Loic and Li, Jingmei and Lindstr{\"o}m, Sara and Linet, Martha and Lo, Wing-Yee and Long, Jirong and Lophatananon, Artitaya and Lubiński, Jan and Manoochehri, Mehdi and Manoukian, Siranoush and Margolin, Sara and Martinez, Elena and Matsuo, Keitaro and Mavroudis, Dimitris and Meindl, Alfons and Menon, Usha and Milne, Roger L. and Mohd Taib, Nur Aishah and Muir, Kenneth and Mulligan, Anna Marie and Neuhausen, Susan L. and Nevanlinna, Heli and Neven, Patrick and Newman, William G. and Offit, Kenneth and Olopade, Olufunmilayo I. and Olshan, Andrew F. and Olson, Janet E. and Olsson, H{\aa}kan and Park, Sue K. and Park-Simon, Tjoung-Won and Peto, Julian and Plaseska-Karanfilska, Dijana and Pohl-Rescigno, Esther and Presneau, Nadege and Rack, Brigitte and Radice, Paolo and Rashid, Muhammad U. and Rennert, Gad and Rennert, Hedy S. and Romero, Atocha and Ruebner, Matthias and Saloustros, Emmanouil and Schmidt, Marjanka K. and Schmutzler, Rita K. and Schneider, Michael O. and Schoemaker, Minouk J. and Scott, Christopher and Shen, Chen-Yang and Shu, Xiao-Ou and Simard, Jaques and Slager, Susan and Smichkoska, Snezhana and Southey, Melissa C. and Spinelli, John J. and Stone, Jennifer and Surowy, Harald and Swerdlow, Anthony J. and Tamimi, Rulla M. and Tapper, William J. and Teo, Soo H. and Terry, Mary Beth and Toland, Amanda E. and Tollenaar, Rob A. E. M. and Torres, Diana and Torres-Mej{\´i}a, Gabriela and Troester, Melissa A. and Truong, Th{\´e}r{\`e}se and Tsugane, Shoichiro and Untch, Michael and Vachon, Celine M. and van den Ouweland, Ans M. W. and van Veen, Elke M. and Vijai, Joseph and Wendt, Camilla and Wolk, Alicja and Yu, Jyh-Cherng and Zheng, Wei and Ziogas, Argyrios and Ziv, Elad and Dunnig, Alison and Pharaoh, Paul D. P. and Schindler, Detlev and Devilee, Peter and Easton, Douglas F.}, title = {Two truncating variants in FANCC and breast cancer risk}, series = {Scientific Reports}, volume = {9}, journal = {Scientific Reports}, organization = {ABCTB Investigators, NBCS Collaborators}, doi = {10.1038/s41598-019-48804-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222838}, year = {2019}, abstract = {Fanconi anemia (FA) is a genetically heterogeneous disorder with 22 disease-causing genes reported to date. In some FA genes, monoallelic mutations have been found to be associated with breast cancer risk, while the risk associations of others remain unknown. The gene for FA type C, FANCC, has been proposed as a breast cancer susceptibility gene based on epidemiological and sequencing studies. We used the Oncoarray project to genotype two truncating FANCC variants (p.R185X and p.R548X) in 64,760 breast cancer cases and 49,793 controls of European descent. FANCC mutations were observed in 25 cases (14 with p.R185X, 11 with p.R548X) and 26 controls (18 with p.R185X, 8 with p.R548X). There was no evidence of an association with the risk of breast cancer, neither overall (odds ratio 0.77, 95\%CI 0.44-1.33, p = 0.4) nor by histology, hormone receptor status, age or family history. We conclude that the breast cancer risk association of these two FANCC variants, if any, is much smaller than for BRCA1, BRCA2 or PALB2 mutations. If this applies to all truncating variants in FANCC it would suggest there are differences between FA genes in their roles on breast cancer risk and demonstrates the merit of large consortia for clarifying risk associations of rare variants.}, language = {en} } @article{KrebsBehrmannKalogirouetal.2019, author = {Krebs, Markus and Behrmann, Christoph and Kalogirou, Charis and Sokolakis, Ioannis and Kneitz, Susanne and Kruithof-de Julio, Marianna and Zoni, Eugenio and Rech, Anne and Schilling, Bastian and K{\"u}bler, Hubert and Spahn, Martin and Kneitz, Burkhard}, title = {miR-221 Augments TRAIL-mediated apoptosis in prostate cancer cells by inducing endogenous TRAIL expression and targeting the functional repressors SOCS3 and PIK3R1}, series = {BioMed Research International}, volume = {2019}, journal = {BioMed Research International}, doi = {10.1155/2019/6392748}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202480}, pages = {6392748}, year = {2019}, abstract = {miR-221 is regarded as an oncogene in many malignancies, and miR-221-mediated resistance towards TRAIL was one of the first oncogenic roles shown for this small noncoding RNA. In contrast, miR-221 is downregulated in prostate cancer (PCa), thereby implying a tumour suppressive function. By using proliferation and apoptosis assays, we show a novel feature of miR-221 in PCa cells: instead of inducing TRAIL resistance, miR-221 sensitized cells towards TRAIL-induced proliferation inhibition and apoptosis induction. Partially responsible for this effect was the interferon-mediated gene signature, which among other things contained an endogenous overexpression of the TRAIL encoding gene TNFSF10. This TRAIL-friendly environment was provoked by downregulation of the established miR-221 target gene SOCS3. Moreover, we introduced PIK3R1 as a target gene of miR-221 in PCa cells. Proliferation assays showed that siRNA-mediated downregulation of SOCS3 and PIK3R1 mimicked the effect of miR-221 on TRAIL sensitivity. Finally, Western blotting experiments confirmed lower amounts of phospho-Akt after siRNA-mediated downregulation of PIK3R1 in PC3 cells. Our results further support the tumour suppressing role of miR-221 in PCa, since it sensitises PCa cells towards TRAIL by regulating the expression of the oncogenes SOCS3 and PIK3R1. Given the TRAIL-inhibiting effect of miR-221 in various cancer entities, our results suggest that the influence of miR-221 on TRAIL-mediated apoptosis is highly context- and entity-dependent.}, language = {en} } @article{MolinasGonzalezCastroGonzalezMegiasetal.2019, author = {Molinas-Gonz{\´a}lez, Carlos R. and Castro, Jorge and Gonz{\´a}lez-Meg{\´i}as, Adela and Leverkus, Alexandro B.}, title = {Effects of post-fire deadwood management on soil macroarthropod communities}, series = {Forests}, volume = {10}, journal = {Forests}, number = {11}, issn = {1999-4907}, doi = {10.3390/f10111046}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193079}, year = {2019}, abstract = {Dead wood comprises a vast amount of biological legacies that set the scene for ecological regeneration after wildfires, yet its removal is the most frequent management strategy worldwide. Soil-dwelling organisms are conspicuous, and they provide essential ecosystem functions, but their possible affection by different post-fire management strategies has so far been neglected. We analyzed the abundance, richness, and composition of belowground macroarthropod communities under two contrasting dead-wood management regimes after a large wildfire in the Sierra Nevada Natural and National Park (Southeast Spain). Two plots at different elevation were established, each containing three replicates of two experimental treatments: partial cut, where trees were cut and their branches lopped off and left over the ground, and salvage logging, where all the trees were cut, logs were piled, branches were mechanically masticated, and slash was spread on the ground. Ten years after the application of the treatments, soil cores were extracted from two types of microhabitat created by these treatments: bare-soil (in both treatments) and under-logs (in the partial cut treatment only). Soil macroarthropod assemblages were dominated by Hemiptera and Hymenoptera (mostly ants) and were more abundant and richer in the lowest plot. The differences between dead-wood treatments were most evident at the scale of management interventions: abundance and richness were lowest after salvage logging, even under similar microhabitats (bare-soil). However, there were no significant differences between microhabitat types on abundance and richness within the partial cut treatment. Higher abundance and richness in the partial cut treatment likely resulted from higher resource availability and higher plant diversity after natural regeneration. Our results suggest that belowground macroarthropod communities are sensitive to the manipulation of dead-wood legacies and that management through salvage logging could reduce soil macroarthropod recuperation compared to other treatments with less intense management even a decade after application.}, language = {en} } @article{WagnerEikenHaubitzetal.2019, author = {Wagner, Johanna and Eiken, Barbara and Haubitz, Imme and Lichthardt, Sven and Matthes, Niels and L{\"o}b, Stefan and Klein, Ingo and Germer, Christoph-Thomas and Wiegering, Armin}, title = {Suprapubic bladder drainage and epidural catheters following abdominal surgery—a risk for urinary tract infections?}, series = {PLoS ONE}, volume = {14}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0209825}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177731}, pages = {e0209825}, year = {2019}, abstract = {Background Epidural catheters are state of the art for postoperative analgesic in abdominal surgery. Due to neurolysis it can lead to postoperative urinary tract retention (POUR), which leads to prolonged bladder catheterization, which has an increased risk for urinary tract infections (UTI). Our aim was to identify the current perioperative management of urinary catheters and, second, to identify the optimal time of suprapubic bladder catheter removal in regard to the removal of the epidural catheter. Methods We sent a questionnaire to 102 German hospitals and analyzed the 83 received answers to evaluate the current handling of bladder drainage and epidural catheters. Then, we conducted a retrospective study including 501 patients, who received an epidural and suprapubic catheter after abdominal surgery at the University Hospital W{\"u}rzburg. We divided the patients into three groups according to the point in time of suprapubic bladder drainage removal in regard to the removal of the epidural catheter and analyzed the onset of a UTI. Results Our survey showed that in almost all hospitals (98.8\%), patients received an epidural catheter and a bladder drainage after abdominal surgery. The point in time of urinary catheter removal was equally distributed between before, simultaneously and after the removal of the epidural catheter (respectively: ~28-29\%). The retrospective study showed a catheter-associated UTI in 6.7\%. Women were affected significantly more often than men (10,7\% versus 2,5\%, p<0.001). There was a non-significant trend to more UTIs when the suprapubic catheter was removed after the epidural catheter (before: 5.7\%, after: 8.4\%). Conclusion The point in time of suprapubic bladder drainage removal in relation to the removal of the epidural catheter does not seem to correlate with the rate of UTIs. The current handling in Germany is inhomogeneous, so further studies to standardize treatment are recommended.}, language = {en} } @article{HovestadtThomasMitesseretal.2019, author = {Hovestadt, Thomas and Thomas, Jeremy A. and Mitesser, Oliver and Sch{\"o}nrogge, Karsten}, title = {Multiple host use and the dynamics of host-switching in host-parasite systems}, series = {Insect Conservation and Diversity}, volume = {12}, journal = {Insect Conservation and Diversity}, number = {6}, doi = {10.1111/icad.12374}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204747}, pages = {511-522}, year = {2019}, abstract = {The link between multi-host use and host switching in host-parasite interactions is a continuing area of debate. Lycaenid butterflies in the genus Maculinea, for example, exploit societies of different Myrmica ant species across their ranges, but there is only rare evidence that they simultaneously utilise multiple hosts at a local site, even where alternative hosts are present. We present a simple population-genetic model accounting for the proportion of two alternative hosts and the fitness of parasite genotypes on each host. In agreement with standard models, we conclude that simultaneous host use is possible whenever fitness of heterozygotes on alternative hosts is not too low. We specifically focus on host-shifting dynamics when the frequency of hosts changes. We find that (i) host shifting may proceed so rapidly that multiple host use is unlikely to be observed, (ii) back and forth transition in host use can exhibit a hysteresis loop, (iii) the parasites' host use may not be proportional to local host frequencies and be restricted to the rarer host under some conditions, and (iv) that a substantial decline in parasite abundance may typically precede a shift in host use. We conclude that focusing not just on possible equilibrium conditions but also considering the dynamics of host shifting in non-equilibrium situations may provide added insights into host-parasite systems.}, language = {en} } @phdthesis{Wilde2019, author = {Wilde, Sabrina}, title = {Einsatz von mechanistischen Biomarkern zur Charakterisierung und Bewertung von \(in\) \(vitro\) Genotoxinen}, doi = {10.25972/OPUS-18278}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-182782}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Die verf{\"u}gbaren in vitro Genotoxizit{\"a}tstests weisen hinsichtlich ihrer Spezifit{\"a}t und ihres Informationsgehalts zum vorliegenden Wirkmechanismus (Mode of Action, MoA) Einschr{\"a}nkungen auf. Um diese M{\"a}ngel zu {\"u}berwinden, wurden in dieser Arbeit zwei Ziele verfolgt, die zu der Entwicklung und Etablierung neuer in vitro Methoden zur Pr{\"u}fung auf Genotoxizit{\"a}t in der Arzneimittelentwicklung beitragen. 1. Etablierung und Bewertung einer neuen in vitro Genotoxizit{\"a}tsmethode (MultiFlow Methode) Die MultiFlow Methode basiert auf DNA-schadensassoziierten Proteinantworten von γH2AX (DNA-Doppelstrangbr{\"u}che), phosphorylierten H3 (S10) (mitotische Zellen), nukle{\"a}ren Protein p53 (Genotoxizit{\"a}t) und cleaved PARP1 (Apoptose) in TK6-Zellen. Insgesamt wurden 31 Modellsubstanzen mit dem MultiFlow Assay und erg{\"a}nzend mit dem etablierten Mikrokerntest (MicroFlow MNT), auf ihre F{\"a}higkeit verschiedene MoA-Gruppen (Aneugene/Klastogene/Nicht-Genotoxine) zu differenzieren, untersucht. Die Performance der „neuen" gegen{\"u}ber der „alten" Methode f{\"u}hrte zu einer verbesserten Sensitivit{\"a}t von 95\% gegen{\"u}ber 90\%, Spezifit{\"a}t von 90\% gegen{\"u}ber 72\% und einer MoA-Klassifizierungsrate von 85\% gegen{\"u}ber 45\% (Aneugen vs. Klastogen). 2. Identifizierung mechanistischer Biomarker zur Klassifizierung genotoxischer Substanzen Die Analyse 67 ausgew{\"a}hlter DNA-schadensassoziierter Gene in der QuantiGene Plex Methode zeigte, dass mehrere Gene gleichzeitig zur MoA-Klassifizierung beitragen k{\"o}nnen. Die Kombination der h{\"o}chstrangierten Marker BIK, KIF20A, TP53I3, DDB2 und OGG1 erm{\"o}glichte die beste Identifizierungsrate der Modellsubstanzen. Das synergetische Modell kategorisierte 16 von 16 Substanzen korrekt in Aneugene, Klastogene und Nicht-Genotoxine. Unter Verwendung der Leave-One-Out-Kreuzvalidierung wurde das Modell evaluiert und erreichte eine Sensitivit{\"a}t, Spezifit{\"a}t und Pr{\"a}diktivit{\"a}t von 86\%, 83\% und 85\%. Ergebnisse der traditionellen qPCR Methode zeigten, dass Genotoxizit{\"a}t mit TP53I3, Klastogenit{\"a}t mit ATR und RAD17 und oxidativer Stress mit NFE2L2 detektiert werden kann. Durch die Untersuchungen von posttranslationalen Modifikationen unter Verwendung der High-Content-Imaging-Technologie wurden mechanistische Assoziationen f{\"u}r BubR1 (S670) und pH3 (S28) mit Aneugenit{\"a}t, 53BP1 (S1778) und FANCD2 (S1404) mit Klastogenit{\"a}t, p53 (K373) mit Genotoxizit{\"a}t und Nrf2 (S40) mit oxidativem Stress identifiziert. Diese Arbeit zeigt, dass (Geno)toxine unterschiedliche Gen- und Proteinver{\"a}nderungen in TK6-Zellen induzieren, die zur Erfassung mechanistischer Aktivit{\"a}ten und Einteilung (geno)toxischer MoA-Gruppen (Aneugen/Klastogen/ Reaktive Sauerstoffspezies) eingesetzt werden k{\"o}nnen und daher eine bessere Risikobewertung von Wirkstoffkandidaten erm{\"o}glichen.}, subject = {Genotoxizit{\"a}t}, language = {de} } @article{ThiemHesbacherKneitzetal.2019, author = {Thiem, Alexander and Hesbacher, Sonja and Kneitz, Hermann and di Primio, Teresa and Heppt, Markus V. and Hermanns, Heike M. and Goebeler, Matthias and Meierjohann, Svenja and Houben, Roland and Schrama, David}, title = {IFN-gamma-induced PD-L1 expression in melanoma depends on p53 expression}, series = {Journal of Experimental \& Clinical Cancer Research}, volume = {38}, journal = {Journal of Experimental \& Clinical Cancer Research}, doi = {10.1186/s13046-019-1403-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201016}, pages = {397}, year = {2019}, abstract = {Background Immune checkpoint inhibition and in particular anti-PD-1 immunotherapy have revolutionized the treatment of advanced melanoma. In this regard, higher tumoral PD-L1 protein (gene name: CD274) expression is associated with better clinical response and increased survival to anti-PD-1 therapy. Moreover, there is increasing evidence that tumor suppressor proteins are involved in immune regulation and are capable of modulating the expression of immune checkpoint proteins. Here, we determined the role of p53 protein (gene name: TP53) in the regulation of PD-L1 expression in melanoma. Methods We analyzed publicly available mRNA and protein expression data from the cancer genome/proteome atlas and performed immunohistochemistry on tumors with known TP53 status. Constitutive and IFN-ɣ-induced PD-L1 expression upon p53 knockdown in wildtype, TP53-mutated or JAK2-overexpressing melanoma cells or in cells, in which p53 was rendered transcriptionally inactive by CRISPR/Cas9, was determined by immunoblot or flow cytometry. Similarly, PD-L1 expression was investigated after overexpression of a transcriptionally-impaired p53 (L22Q, W23S) in TP53-wt or a TP53-knockout melanoma cell line. Immunoblot was applied to analyze the IFN-ɣ signaling pathway. Results For TP53-mutated tumors, an increased CD274 mRNA expression and a higher frequency of PD-L1 positivity was observed. Interestingly, positive correlations of IFNG mRNA and PD-L1 protein in both TP53-wt and -mutated samples and of p53 and PD-L1 protein suggest a non-transcriptional mode of action of p53. Indeed, cell line experiments revealed a diminished IFN-ɣ-induced PD-L1 expression upon p53 knockdown in both wildtype and TP53-mutated melanoma cells, which was not the case when p53 wildtype protein was rendered transcriptionally inactive or by ectopic expression of p53\(^{L22Q,W23S}\), a transcriptionally-impaired variant, in TP53-wt cells. Accordingly, expression of p53\(^{L22Q,W23S}\) in a TP53-knockout melanoma cell line boosted IFN-ɣ-induced PD-L1 expression. The impaired PD-L1-inducibility after p53 knockdown was associated with a reduced JAK2 expression in the cells and was almost abrogated by JAK2 overexpression. Conclusions While having only a small impact on basal PD-L1 expression, both wildtype and mutated p53 play an important positive role for IFN-ɣ-induced PD-L1 expression in melanoma cells by supporting JAK2 expression. Future studies should address, whether p53 expression levels might influence response to anti-PD-1 immunotherapy.}, language = {en} } @article{VeyKapsnerFuchsetal.2019, author = {Vey, Johannes and Kapsner, Lorenz A. and Fuchs, Maximilian and Unberath, Philipp and Veronesi, Giulia and Kunz, Meik}, title = {A toolbox for functional analysis and the systematic identification of diagnostic and prognostic gene expression signatures combining meta-analysis and machine learning}, series = {Cancers}, volume = {11}, journal = {Cancers}, number = {10}, issn = {2072-6694}, doi = {10.3390/cancers11101606}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193240}, year = {2019}, abstract = {The identification of biomarker signatures is important for cancer diagnosis and prognosis. However, the detection of clinical reliable signatures is influenced by limited data availability, which may restrict statistical power. Moreover, methods for integration of large sample cohorts and signature identification are limited. We present a step-by-step computational protocol for functional gene expression analysis and the identification of diagnostic and prognostic signatures by combining meta-analysis with machine learning and survival analysis. The novelty of the toolbox lies in its all-in-one functionality, generic design, and modularity. It is exemplified for lung cancer, including a comprehensive evaluation using different validation strategies. However, the protocol is not restricted to specific disease types and can therefore be used by a broad community. The accompanying R package vignette runs in ~1 h and describes the workflow in detail for use by researchers with limited bioinformatics training.}, language = {en} } @article{LyutovaSelchoPfeufferetal.2019, author = {Lyutova, Radostina and Selcho, Mareike and Pfeuffer, Maximilian and Segebarth, Dennis and Habenstein, Jens and Rohwedder, Astrid and Frantzmann, Felix and Wegener, Christian and Thum, Andreas S. and Pauls, Dennis}, title = {Reward signaling in a recurrent circuit of dopaminergic neurons and peptidergic Kenyon cells}, series = {Nature Communications}, volume = {10}, journal = {Nature Communications}, doi = {10.1038/s41467-019-11092-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202161}, pages = {3097}, year = {2019}, abstract = {Dopaminergic neurons in the brain of the Drosophila larva play a key role in mediating reward information to the mushroom bodies during appetitive olfactory learning and memory. Using optogenetic activation of Kenyon cells we provide evidence that recurrent signaling exists between Kenyon cells and dopaminergic neurons of the primary protocerebral anterior (pPAM) cluster. Optogenetic activation of Kenyon cells paired with odor stimulation is sufficient to induce appetitive memory. Simultaneous impairment of the dopaminergic pPAM neurons abolishes appetitive memory expression. Thus, we argue that dopaminergic pPAM neurons mediate reward information to the Kenyon cells, and in turn receive feedback from Kenyon cells. We further show that this feedback signaling is dependent on short neuropeptide F, but not on acetylcholine known to be important for odor-shock memories in adult flies. Our data suggest that recurrent signaling routes within the larval mushroom body circuitry may represent a mechanism subserving memory stabilization.}, language = {en} } @phdthesis{Breitenbach2019, author = {Breitenbach, Tim}, title = {A mathematical optimal control based approach to pharmacological modulation with regulatory networks and external stimuli}, doi = {10.25972/OPUS-17436}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174368}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In this work models for molecular networks consisting of ordinary differential equations are extended by terms that include the interaction of the corresponding molecular network with the environment that the molecular network is embedded in. These terms model the effects of the external stimuli on the molecular network. The usability of this extension is demonstrated with a model of a circadian clock that is extended with certain terms and reproduces data from several experiments at the same time. Once the model including external stimuli is set up, a framework is developed in order to calculate external stimuli that have a predefined desired effect on the molecular network. For this purpose the task of finding appropriate external stimuli is formulated as a mathematical optimal control problem for which in order to solve it a lot of mathematical methods are available. Several methods are discussed and worked out in order to calculate a solution for the corresponding optimal control problem. The application of the framework to find pharmacological intervention points or effective drug combinations is pointed out and discussed. Furthermore the framework is related to existing network analysis tools and their combination for network analysis in order to find dedicated external stimuli is discussed. The total framework is verified with biological examples by comparing the calculated results with data from literature. For this purpose platelet aggregation is investigated based on a corresponding gene regulatory network and associated receptors are detected. Furthermore a transition from one to another type of T-helper cell is analyzed in a tumor setting where missing agents are calculated to induce the corresponding switch in vitro. Next a gene regulatory network of a myocardiocyte is investigated where it is shown how the presented framework can be used to compare different treatment strategies with respect to their beneficial effects and side effects quantitatively. Moreover a constitutively activated signaling pathway, which thus causes maleficent effects, is modeled and intervention points with corresponding treatment strategies are determined that steer the gene regulatory network from a pathological expression pattern to physiological one again.}, subject = {Bioinformatik}, language = {en} } @article{MatosMachadoSchartletal.2019, author = {Matos, Isa and Machado, Miguel P. and Schartl, Manfred and Coelho, Maria Manuela}, title = {Allele-specific expression variation at different ploidy levels in Squalius alburnoides}, series = {Scientific Reports}, volume = {9}, journal = {Scientific Reports}, doi = {10.1038/s41598-019-40210-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200910}, pages = {3688}, year = {2019}, abstract = {Allopolyploid plants are long known to be subject to a homoeolog expression bias of varying degree. The same phenomenon was only much later suspected to occur also in animals based on studies of single selected genes in an allopolyploid vertebrate, the Iberian fish Squalius alburnoides. Consequently, this species became a good model for understanding the evolution of gene expression regulation in polyploid vertebrates. Here, we analyzed for the first time genome-wide allele-specific expression data from diploid and triploid hybrids of S. alburnoides and compared homoeolog expression profiles of adult livers and of juveniles. Co-expression of alleles from both parental genomic types was observed for the majority of genes, but with marked homoeolog expression bias, suggesting homoeolog specific reshaping of expression level patterns in hybrids. Complete silencing of one allele was also observed irrespective of ploidy level, but not transcriptome wide as previously speculated. Instead, it was found only in a restricted number of genes, particularly ones with functions related to mitochondria and ribosomes. This leads us to hypothesize that allelic silencing may be a way to overcome intergenomic gene expression interaction conflicts, and that homoeolog expression bias may be an important mechanism in the achievement of sustainable genomic interactions, mandatory to the success of allopolyploid systems, as in S. alburnoides.}, language = {en} } @phdthesis{Memmel2019, author = {Memmel, Simon}, title = {Automatisierte Algorithmen zur Analyse der Migration und der strahleninduzierten DNA-Sch{\"a}den humaner Glioblastomzellen nach kombinierter PI3K/mTOR/Hsp90-Inhibierung}, doi = {10.25972/OPUS-18571}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-185710}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Das hohe invasive Potential und die starke Resistenz gegen Radio-/Chemotherapie von Glioblastoma multiforme (GBM) Zellen machen sie zu dem t{\"o}dlichsten Tumor ihrer Art. Es ist deshalb von großem Interesse die Grundlagen, welche der Migrationsf{\"a}higkeit und DNA Reparatur zu Grunde liegen, besser zu verstehen. Im ersten Teil dieser Arbeit wurden zwei Algorithmen zur automatischen Analyse der Migration in der Einzelzellverfolgung und im Wundheilungsassay modifiziert. Die Auswertung der Daten konnte automatisch und somit schnell, effektiv und mit geringerem Arbeitsaufwand durchgef{\"u}hrt werden. Mit Hilfe dieser automatischen Algorithmen wurde die Migrationsf{\"a}higkeit von zwei GBM-Zelllinien (DK-MG und SNB19) untersucht. Zus{\"a}tzlich wurde die konfokale Laserscanning- sowie die hochaufl{\"o}sende dSTORM-Fluoreszenzmikroskopie verwendet um die, der Zellbewegung zu Grunde liegende, Struktur des F Aktin und der fokalen Adh{\"a}sionskinase (FAK) aufzul{\"o}sen und darzustellen. Unter Anwendung dieser genannten Methoden sind die Effekte des dualen PI3K/mTOR Inhibitors PI-103 alleine und in Kombination mit dem Hsp90 Inhibitor NVP AUY922 mit und ohne Bestrahlung auf die Bewegung untersucht worden. Es konnte festgestellt werden, dass sich beide Zelllinien deutlich in ihrem migratorischem Potential in vitro unterscheiden und zudem auch markante Unterschiede in ihrer Morphologie aufweisen. Die weniger invasiven DK MG-Zellen besitzen eine polarisierte Zellstruktur, wohingegen SNB19-Zellen sich durch multipolare ungerichtete Bewegung auszeichneten. Zudem wurde die Migration, durch PI3K/mTOR Inhibition mit PI-103 bei den DK-MG-Zellen (p53 wt, PTEN wt), sehr effektiv unterdr{\"u}ckt. Wohingegen sich die SNB19-Zellen (p53 mut, PTEN mut) resistent gegen diesen Inhibitor zeigten. Hsp90 Inhibition offenbarte in beiden Zelllinien einen starken inhibitorischen Effekt auf die Migration der Zellen sowie die Reorganisierung des F Aktinskelettes. In der zweiten H{\"a}lfte dieser Arbeit wurde ein Augenmerk auf die DNA-DSB-Reparatur der GBM Zellen nach ionisierender Strahlung gelegt. Zun{\"a}chst wurde eine automatische Analysesoftware „FocAn-3D" entwickelt, mit dessen Hilfe die DNA Doppelstrangbruchreparaturkinetik untersucht werden sollte. Diese Software erm{\"o}glicht es die gesamten Zellkerne mit ihren γH2AX-Foci in 3D-cLSM-Aufnahmen zu untersuchen. Es konnte somit eine Verbesserung der Genauigkeit in der Ausz{\"a}hlung der γH2AX-Foci erreicht werden, welche 2D beschr{\"a}nkter Software verwehrt bleibt. Mit FocAn-3D konnte der gesamte Verlauf der Induktions- und Abbauphase der γH2AX-Foci in DK MG- und SNB19-Zellen mit einem mathematischen Modell ausgewertet und dargestellt werden. Des Weiteren wurde die Nanometerstruktur von γH2AX- und pDNA-PKcs-Foci mittels hochaufl{\"o}sender dSTORM-Mikroskopie untersucht. Konventionelle Mikroskopiemethoden, begrenzt durch das Beugungslimit und einer Aufl{\"o}sung von ~200 nm, konnten die Nanometerstruktur (<100 nm) der Reparaturfoci bisher nicht darstellen. Mit Hilfe der beugungsunbegrenzten dSTORM-Mikroskopie war es m{\"o}glich in DK MG- und SNB19-Zellen die Nanometerstruktur genannten Reparaturproteine in den Foci mit einer Aufl{\"o}sung von bis zu ~20 nm darzustellen. γH2AX-Foci zeigten sich als eine Verteilung aus einzelnen Untereinheiten („Nanofoci") mit einem Durchmesser von ~45 nm. Dies l{\"a}sst die Vermutung zu, dass es sich hier um die elementare Substruktur der Foci und somit der γH2AX enthaltenen Nukleosome handelt. DNA-PK-Foci wiesen hingegen eine diffusere Verteilung auf. Die in dieser Arbeit ermittelten Unterschiede im Migrationsverhalten der Zellen rechtfertigen eine weitere pr{\"a}klinische Untersuchung der verwendeten Inhibitoren als potentielle Zelltherapeutika f{\"u}r die Behandlung von GBM. Zudem konnte sich dSTORM als machtvolles Hilfsmittel, sowohl zur Analyse der Migration zugrundeliegenden Zytoskelettstruktur und der Effekte der Hsp90 Inhibierung, als auch, der Nanostruktur der DNA-DSB-Reparaturfoci herausstellen. Es ist anzunehmen, dass beugungsunbegrenzte Mikroskopiemethoden sich als bedeutende Werkzeuge in der medizinischen und biologischen Erforschung der DNA-Reparaturmechanismen herausstellen werden. Das in dieser Arbeit entwickelte ImageJ Plugin „FocAn-3D" bewies sich ebenfalls als ein vielversprechendes Werkzeug f{\"u}r die Analyse der Reparaturkinetik. Mit Hilfe von „FocAn-3D" sollte es somit m{\"o}glich sein u.a. den Einfluss gezielter Inhibition auf den zeitlichen Verlauf der Induktion und des Abbaus der DNA-Reparaturmaschinerie genauer zu studieren.}, subject = {Glioblastom}, language = {de} } @phdthesis{Kaymak2019, author = {Kaymak, Irem}, title = {Identification of metabolic liabilities in 3D models of cancer}, doi = {10.25972/OPUS-18154}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181544}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Inefficient vascularisation of solid tumours leads to the formation of oxygen and nutrient gradients. In order to mimic this specific feature of the tumour microenvironment, a multicellular tumour spheroid (SPH) culture system was used. These experiments were implemented in p53 isogenic colon cancer cell lines (HCT116 p53 +/+ and HCT116 p53-/-) since Tp53 has important regulatory functions in tumour metabolism. First, the characteristics of the cells cultured as monolayers and as spheroids were investigated by using RNA sequencing and metabolomics to compare gene expression and metabolic features of cells grown in different conditions. This analysis showed that certain features of gene expression found in tumours are also present in spheroids but not in monolayer cultures, including reduced proliferation and induction of hypoxia related genes. Moreover, comparison between the different genotypes revealed that the expression of genes involved in cholesterol homeostasis is induced in p53 deficient cells compared to p53 wild type cells and this difference was only detected in spheroids and tumour samples but not in monolayer cultures. In addition, it was established that loss of p53 leads to the induction of enzymes of the mevalonate pathway via activation of the transcription factor SREBP2, resulting in a metabolic rewiring that supports the generation of ubiquinone (coenzyme Q10). An adequate supply of ubiquinone was essential to support mitochondrial electron transport and pyrimidine biosynthesis in p53 deficient cancer cells under conditions of metabolic stress. Moreover, inhibition of the mevalonate pathway using statins selectively induced oxidative stress and apoptosis in p53 deficient colon cancer cells exposed to oxygen and nutrient deprivation. This was caused by ubiquinone being required for electron transfer by dihydroorotate dehydrogenase, an essential enzyme of the pyrimidine nucleotide biosynthesis pathway. Supplementation with exogenous nucleosides relieved the demand for electron transfer and restored viability of p53 deficient cancer cells under metabolic stress. Moreover, the mevalonate pathway was also essential for the synthesis of ubiquinone for nucleotide biosynthesis to support growth of intestinal tumour organoids. Together, these findings highlight the importance of the mevalonate pathway in cancer cells and provide molecular evidence for an enhanced sensitivity towards the inhibition of mitochondrial electron transfer in tumour-like metabolic environments.}, subject = {Tumor}, language = {en} }