TY - THES A1 - Müller, Nicole T1 - Modellierung klonaler Evolution beim Multiplen Myelom T1 - Modeling Clonal Evolution in Multiple Myeloma N2 - In dieser Arbeit wurde ein modulares Zelllinienmodell zur Visualisierung klonaler Evolutionsmechanismen etabliert. Hierfür wurden unterschiedlich fluoreszierende Proteine (LSSmKate2, EGFP, mTagBFP2) durch Anwendung eines Sleeping Beauty basierten Vektorsystems in unterschiedliche Sublinien der Myelom Zelllinie L363 eingebracht. Diese vier Sublinien beinhalten jeweils eine von drei aus primären Patientenproben gewonnenen Mutationen in IKZF1 (A152T, E170D, R439H) oder den IKZF1 WT. Die Anwendung von immunmodulatorischen Medikamenten (IMiDs) führt zu einer Ubiquitinierung des Transkriptionsfaktors IKZF1 durch die E3-Ubiquitin-Protein-Ligase (CRBN-CUL4). Durch Mutationen in IKZF1 kommt es zu Störungen in diesem Prozess und damit zu einer Überexpression von IKZF1. Dies wirkt sich wachstumsfördert auf die Myelomzellen aus. Die Auswirkungen der einzelnen Mutationen in IKZF1 ist aufgrund dessen ein klinisch relevantes Forschungsthema. In dieser Arbeit wurden jeweils zwei Sublinien mit Zellen des IKZF1 WT und Zellen mit einer IKZF1 Mutation mit jeweils unterschiedlich fluoreszierenden Proteinen markiert. Diese wurden gemeinsam unter Behandlung mit verschiedenen Konzentrationen von Lenalidomid inkubiert. Somit konnte das Selektionsverhalten mittels Durchflusszytometrie-Auswertungen visualisiert werden. Es konnte gezeigt werden, dass die IKZF1 Mutation A152T einen deutlichen Selektionsvorteil für die Myelomzellen darstellt. Bei den IKZF1 Mutationen E170D und R439H konnte kein Selektionsvorteil gegenüber dem IKZF1 WT beobachtet werden. N2 - In this work, a modular cell line model was established to visualize clonal evolutionary mechanisms. Different fluorescent proteins (LSSmKate2, EGFP, mTagBFP2) were introduced into various sublines of the myeloma cell line L363 using a Sleeping Beauty-based vector system. These four sublines each contain one of three mutations in IKZF1 (A152T, E170D, R439H) derived from primary patient samples or the IKZF1 wild type (WT). The application of immunomodulatory drugs (IMiDs) leads to the ubiquitination of the transcription factor IKZF1 by the E3 ubiquitin-protein ligase (CRBN-CUL4). Mutations in IKZF1 disrupt this process, resulting in the overexpression of IKZF1, which promotes the growth of myeloma cells. The effects of individual mutations in IKZF1 are therefore a clinically relevant research topic. In this study, two sublines each with IKZF1 WT cells and cells with an IKZF1 mutation were labeled with different fluorescent proteins. These were incubated together under treatment with various concentrations of lenalidomide. Thus, the selection behavior could be visualized using flow cytometry analyses. It was shown that the IKZF1 mutation A152T provides a clear selective advantage for the myeloma cells. No selective advantage was observed for the IKZF1 E170D and R439H mutations compared to IKZF1 WT. KW - Lenalidomid KW - Plasmozytom KW - IKZF1 KW - klonale Evolution KW - Vektormodell KW - Multiples Myelom Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-370818 ER - TY - THES A1 - Rode, Stefan T1 - Automated resummation of electroweak Sudakov logarithms in diboson production T1 - Automatisierte Resummierung elektroschwacher Sudakov-Logarithmen in Vektorboson-Paarproduktion N2 - The present thesis is concerned with the automated computation of integrated and differential cross sections of diboson production in proton–proton and electron–positron collisions at very high energies, including a resummation of electroweak Sudakov logarithms to all orders in the fine-structure constant using soft–collinear effective theory. The search for new physics at future colliders such as the FCC–hh or the CLIC requires precise predictions for scattering cross sections from the theoretical high-energy physics com- munity. Electroweak Sudakov logarithms, which currently limit the accuracy of predictions in the high-energy tails of differential distributions for LHC-like energies, are known to destroy the convergence behaviour of the fixed-order perturbative series, once sufficiently high energies are considered. To resum these large corrections, soft–collinear effective theory has been applied to simple processes, which permits analytic calculations. Within this work, we present an automated computation within a Monte Carlo integration framework, thus facilitating the computation of fully differential cross section to complicated processes. This requires the use of the Catani– Seymour subtraction algorithm to treat the occurring infrared divergences. The machinery is applied to all diboson processes with intermediate weak gauge bosons, including the photon- induced W+ W− -production channel. To this end we carefully study the validity of the necessary assumptions such as the double- pole approximation and estimate the order of magnitude of neglected effects. Especially the non-doubly-resonant contributions turn out to be sizeable in several interesting phase-space regions. For lepton collisions at 3 TeV we obtain the integrated cross sections of W-pair and Z-pair production to be shifted by more than 20% with respect to the Born value, owing to the resum- mation of the leading-logarithmic corrections These effects are partly cancelled by subleading effects. For proton–proton collisions at √ s = 100 TeV we observe sizeable resummation effects in the high-energy tails, while the integrated cross sections are dominated by interactions, for which soft–collinear effective theory is not applicable. N2 - Das Thema ist der vorliegenen Arbeit ist die automatisierte Berechnung differenzieller und integrierter Wirkungsquerschnitte der Paarerzeugung schwerer Eichbosonen bei sehr hohen Streuenergien mit Resummierung der auftretenden elektroschwachen Sudakov-Logarithmen zu allen Ordnungen in der Feinstrukturkonstanten mittels Soft-Collinear Effective Theory. Die Suche nach Physik jenseits des Standardmodells an zukunftigen Teilchenbeschleunigern wie dem FCC oder dem CLIC erfordert hochpräzise Voraussagen fur Streuquerschnitte seitens der theoretischen Physik. Es ist seit langem bekannt, dass elektroschwache Sudakov-Logarithmen, die bereits gegenwärtig die Genauigkeit der Voraussagen in den Hochenergieschwänzen von Verteilungen limitieren, die Konvergenz der konventionellen Störungsreihen vollkommen zunichte machen, wenn hinreichend hohe Energien erreicht werden. Mittels Soft-Collinear Effective Theory wurden diese Logarithmen bereits in der Vergangenheit in einfachen Prozessen, die eine analytische Behandlung erlauben, resummiert. Im Rahmen dieser Arbeit wurden diese Methoden in ein Monte-Carlo-Integrationsprogramm implementiert, um somit vollständig differenzielle Vorhersagen präsentieren zu können. Dies erfordert die Behandlung von Infrarotdivergenzen mit Hilfe des Catani-Seymour-Algorithmus. Mit diesen Werkzeugen wurden resummierte Streuquerschnitte fur verschiedene Vektorboson-Paarproduktionsprozesse berechnet, u.a. fur den Photon-Photon-induzierten Produktionskanal zur W-Boson-Paarproduktion. Auf dem Weg dorthin sind verschiedene vereinfachende Annahmen notwendig, deren Gultigkeit im Rahmen dieser Arbeit ebenfalls getestet wurde, so z.B. die Qualität der Doppelpolnäherung. Des weiteren wurden Größenordnungen vernachlässigter Effekte abgeschätzt. Dabei haben sich vor allem nicht doppelt resonante Beiträge in bestimmten Phasenraumregionen als beträchtlich herausgestellt. Der Resummationseffekt der fuhrend logarithmischen Korrekturen verschiebt die integrierten Paarproduktionsstreuquerschnitte um mehr als 20% bezogen auf den Bornstreuquerschnitt im Falle von Leptonkollisionen bei einer Schwerpunktsenergie von 3 TeV. Diese Effekte werden allerdings teilweise von nicht-führenden Beiträgen kompensiert. Fur Proton-Proton-Kollisionen bei √ s = 100 TeV finden wir deutliche Resummationseffekte in allen Hochenergieschwänzen, während die integrierten Wirkungsquerschnitte von Phasenraumregionen dominiert werden, in denen Soft-Collinear Effective Theory nicht anwendbar ist. KW - High-energy physics Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-371060 ER - TY - THES A1 - Aljasem, Anwar T1 - Der Einfluss des Hepatocyte growth factors auf die PD-L1-Expression in Kopf-Hals-Karzinomen: Die Bedeutung des MAPK-, AKT- und STAT3-Signalwegs T1 - The impact of Hepatocyte growth factor (HGF) on PD-L1 expression in HNSCC: The meaning of MAPK, AKT, and STAT3 signaling pathways N2 - Die zielgerichtete Therapie und die Immuncheckpoint-Inhibitoren haben die Tumortherapie revolutioniert. Während erstere die Tumorzellen gezielt angreift, verhindern letztere die Hemmung des Immunsystems durch Immuncheckpoints, um eine robuste Immunantwort zu erreichen. Zusätzlich ist das Nebenwirkungsprofil bei direktem Vergleich mit der konventionellen Chemotherapie günstiger. Beim HNSCC werden beide Ansätze angewendet. Cetuximab ist ein monoklonaler Antikörper, der sich gegen EGFR, welcher bei HNSCC überexprimiert ist, richtet. Nivolumab und Pembrolizumab richten sich gegen das Immuncheckpoint-Protein PD-1. Nach wie vor sind die Resistenzen, sowohl die initialen als auch die erworbenen, die größte zu überwindende Herausforderung. Aufbauend auf dem Ergebnis vorangegangener Arbeiten, die zeigen konnten, dass HGF über c-MET die Expression des Immuncheckpointliganden PD-L1 steigert, setzt sich diese Arbeit weiter mit den intrazellulären nachgeschalteten Signalwegen nach c-MET Aktivierung auseinander. Dies ist von besonderem Interesse, weil diese Signalwege ebenfalls für die Resistenzentwicklung verantwortlich sein können, zeitgleich können diese im Rahmen der zielgerichteten Therapie gezielt inhibiert werden. Um den HGF-Einfluss auf die intrazellulären Signalwege zu prüfen, wurden vier etablierte HNSCC-Zelllinien herangezogen. Im ersten Teil der Arbeit wurden die 4 HNSCC-abgeleitete Zelllinien mit HGF stimuliert und mittels Western Blot der PD-L1-Anstieg und die Phosphorylierungsänderung der Schlüsselproteine der einzelnen Signalwege nachgewiesen. Daraus ergab sich, dass HGF die MAPK- und PIK3/AKT-Signalwege aktiviert. Während eine kombinierte Blockade des MAPK-Signalwegs den PD-L1-Anstieg vollständig verhindern konnte, hemmte die PIK3/AKT-Blockade den PD-L1-Anstieg nur partiell. Im zweiten Teil wurde mit siRNA der hauptsächlich für den PD-L1-Anstieg zuständige MAPK-Signalweg unterbunden, was mittels quantitativer PCR auf der mRNA-Ebene nachgewiesen werden konnte. Mittels Western Blot konnte entsprechend gezeigt werden, dass der PD-L1-Anstieg trotz HGF-Stimulation bei nicht funktionsfähigem MAPK-Signalweg eingeschränkt war. Weiter wurde der Effekt mit dem Medikament Trametinib, das im Rahmen der zielgerichteten Therapie bei malignem Melanom und NSCLC für die MAPK-Signalweg-Hemmung zugelassen ist, evaluiert. Sowohl im Western Blot als auch in der Durchflusszytometrie konnte bestätigt werden, dass Trametinib den HGF-induzierten Anstieg von PD-L1 signifikant blockiert. Darüber hinaus konnte im Rahmen der Western Blot-Versuche gezeigt werden, dass die Signalwege und die PD-L1-Expression in den Zelllinien unterschiedlich aktiv bzw. hoch waren. Unter den vier Zelllinien zeigte die FaDu-Zelllinie eine erhöhte PI3K/AKT-Aktivität, Detroit562 und SCC9 eine erhöhte MAPK-Aktivität. Die PD-L1- Expression war in der SCC9-Zelllinie am höchsten. Die Arbeit zeigt eine einheitliche Reaktion der HNSCC-Zelllinien auf den Wachstumsfaktor HGF, welcher im Tumormilieu von HNSCC oft in hoher Konzentration vorhanden ist. Neben dem EGFR-Antikörper (Cetuximab) kann eine kombinierte Hemmung entweder von c-MET oder von den nachgeschalteten Signalwegen MAPK und PI3K/AKT bei Resistenzen, Progression oder Unverträglichkeiten eine Möglichkeit für eine wirksamere Therapie von HNSCC darstellen. Ein Screening der Signalwege und deren Aktivierungsmechanismen könnte bei Resistenzen oder bei einem Rezidiv/Progress dazu beitragen, gezielt die alternative Aktivierung zu hemmen und möglicherweise die Wirksamkeit einer Immuncheckpointblockade zu verbessern. N2 - Targeted therapy and immune checkpoint inhibitors have revolutionized tumor therapy. While the former specifically targets tumor cells, the latter prevents inhibitory immune responses via immune checkpoints to achieve a robust immune response. Additionally, the side effect profile is more favorable when directly compared to conventional chemotherapy. Both approaches are approved for the treatment of Head and Neck Squamous Cell Carcinoma (HNSCC). Cetuximab is a monoclonal antibody that targets EGFR, which is overexpressed in HNSCC. Nivolumab and Pembrolizumab target the immune checkpoint protein PD-1. Resistances, both initial and acquired, however, remain significant challenges to overcome. Building on a previous report that HGF upregulates the immune checkpoint ligand PD-L1 expression via the c-MET pathway, this study investigates the intracellular downstream signaling pathways activated by HGF. This is of particular interest because these signaling pathways contribute to resistance development, while at the same time, they can be specifically inhibited in the context of targeted therapy. To examine the influence of HGF on intracellular signaling pathways, four established HNSCC cell lines were utilized. In the first part of the study, the four HNSCC-derived cell lines were stimulated with HGF, and the increase in PD-L1 expression and changes in phosphorylation levels of key proteins in the individual signaling pathways were analyzed using Western Blots. It was found that HGF activates the MAPK and PI3K/AKT pathways. While MAPK inhibition completely blocked the PD-L1 increase, PI3K/AKT inhibition only partially did so after HGF stimulation. In the second part, the MAPK pathway, mainly responsible for the increase in PD-L1, was inhibited using siRNA. Quantitative PCR validated corresponding mRNA levels. Western Blots further showed that the increase in PD-L1 was reduced despite HGF stimulation when the MAPK pathway was non-functional. In line with previous results, inhibiting MAPKs with the drug Trametinib, which is approved as a targeted therapy for malignant melanoma and NSCLC, significantly blocks HGF-induced PD-L1 expression based on Western Blot and flow cytometry analysis. Notably, the activity of the different signaling pathways and the expression levels of PD-L1 vary among the different cell lines, as Western Blot analyses reveal. For instance, while the FaDu cell line manifested high activity in the PI3K/AKT pathway, Detroit562 and SCC9 showed increased MAPK activity. Nonetheless, the SCC9 cell line showed the highest PD-L1 expression level. This study demonstrated that HNSCC cell lines similarly respond to the growth factor HGF, which is frequently present in high concentrations in the tumor microenvironment of HNSCC. Additionally, the inhibition of c-MET and its downstream MAPK or PI3K/AKT pathways in combination with EGFR blockade by Cetuximab may offer a more effective treatment strategy for HNSCC patients in cases of therapeutic resistance, disease progression, or drug intolerance. Screening of the signaling pathways and their activation mechanisms could, in cases of resistance, recurrence, or progression, contribute to the specific inhibition of alternative activation and potentially improve the efficacy of immune checkpoint blockade. KW - Hepatozyten-Wachstumsfaktor KW - MAP-Kinase KW - Plattenepithelcarcinom KW - PD-L1 Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-370358 ER - TY - THES A1 - Lechermeier, Carina T1 - Neuroanatomical and functional evaluation of ADHD candidate genes in the model organism zebrafish (\(Danio\) \(rerio\)) T1 - Neuroanatomische und funktionelle Auswertung von ADHS Kandidatengenen im Modellorganismus Zebrafisch (\(Danio\) \(rerio\)) N2 - Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent developmental disorders, affecting 5.9% children and adolescents and 2.5% adults worldwide. The core characteristics are age-inappropriate levels of hyperactivity, impulsivity and inattention, often accompanied by co-morbidities such as mood and conduct disorders as wells as learning deficits. In the majority of cases, ADHD is caused by an interplay of accumulated genetic and environmental risk factors. Twin studies report a very high heritability of 70–80%, however, common genetic variants in the population only explain a third of the heritability. The rest of the genetic predisposition is composed of rare copy number variations (CNVs) and gene x environment interactions including epigenetic alterations. Through genome wide association (GWAS) and linkage studies a number of likely candidate genes were identified. A handful of them play a role in dopamine or noradrenaline neurotransmitter systems, simultaneously those systems are the main targets of common drug treatment approaches. However, for the majority of candidates the biological function in relation to ADHD is unknown. It is crucial to identify those functions in order to gain a deeper understanding of the pathomechanism and genetic networks potentially responsible for the disorder. This work focuses on the three candidate genes GFOD1, SLC2A3 and LBX1 and their role in the healthy organism as well as in case of ADHD. The neuroanatomy was regarded through expression analysis and various behavioural assays of activity were performed to link alterations on the transcript level to phenotypes associated with the neurodevelopmental disorder. Zebrafish orthologues of the human risk genes were identified and extensive temporal and spacial expression characterisation performed via RNA in situ hybridisation. Through morpholino derived knock-down and mRNA overexpression zebrafish models with subsequent behavioural analysis, both hyper- and hypoactive phenotypes were discovered. Additional expression analysis through double in situ hybridisation revealed a co-localisation during zebrafish neurodevelopment of each gfod1 and slc2a3a together with gad1b, a marker for GABAergic neurons. Interestingly, both risk genes have previously been associated with glucose homeostasis and energy metabolism, which when disrupted could lead to alterations in signal transduction and neuron survival. Likewise, Lbx1 plays a pivotal role in GABAergic versus glutamatergic neuron specification during spinal cord and hindbrain development in mice and chicken. Preliminary results of this work suggest a similar role in zebrafish. Taken together, those findings on the one hand represent a sturdy basis to con- tinue studies of the function of the genes and on the other hand open up the opportunity to investigate novel aspects of ADHD research by exploring the role of the GABAergic neurotransmitter system or the connection between energy metabolism and psychiatric disorders. N2 - Die Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) ist eine der am weitesten verbreiteten Entwicklungsstörungen, davon sind 5,9% Kinder und Jugendliche und 2,5% Erwachsene weltweit betroffen. Die Kernsymptome sind altersunangemessene Hyperaktivität, Impulsivität und Unaufmerksamkeit, oft begleitet von Begleiterkrankungen wie emotionale Dysregulation oder Verhal- tensauffälligkeiten sowie Lerndefiziten. In den meisten Fällen wird ADHS durch ein Zusammenspiel von angehäuften genetischen und umweltbedingten Risikofaktoren verursacht. Durch Zwillingsstudien gelang man zu einer errechneten Erblichkeit von 70–80%, jedoch erklären häufig auftretende genetische Varianten in der Bevölkerung nur ein Drittel der Erblichkeit. Der Rest der genetischen Veranlagung setzt sich aus seltenen Kopienzahlvariationen (CNV) und Interaktionen von Gen x Umwelt, einschließlich epigenetischer Veränderungen, zusammen. Durch genomweite Assoziationsstudien (GWAS) und Kopplungsanalysen wurden eine Reihe von wahrscheinlichen Kandidatengenen identifiziert. Eine Handvoll von ihnen spielen eine Rolle in den Dopamin oder Noradrenalin Neurotransmittersystemen. Diese Systeme sind gleichzeitig die Hauptangriffspunkte der gängigsten Medikamente, die zur Behandlung von ADHS eingesetzt werden. Allerdings ist für die Mehrheit der Kandidatengene die biologische Funktion in Bezug auf ADHS unbekannt. Es ist essentiell diese Funktionen zu identifizieren um ein tieferes Verständnis der Ätiopathogenese und der genetische Netzwerke, die möglicherweise für die Störung verantwortlich sind, zu erlangen. Diese Arbeit konzentriert sich auf die drei Kandidatengene GFOD1, SLC2A3 und LBX1 und ihre Rolle im gesunden Organismus sowie während ADHS. Die Neuroanatomie wurde durch Expressionsanalyse betrachtet und verschiedene aktivitätsbasierte Verhaltensessays wurden durchgeführt, um Veränderungen auf Transkriptebene mit den zugehörigen Phänotypen der neurologischen Entwick- lungsstörung in Verbindung zu bringen. Zebrafischorthologe der menschlichen Kandidatengene wurden identifiziert und umfangreiche zeitliche und räumli- che Expressionsanalysen via RNA in situ Hybridisierung durchgeführt. Durch Morpholino-Knockdown und mRNA-Überexpressions Zebrafischmodelle mit anschließender Verhaltensanalyse wurden sowohl hyper- als auch hypoaktive Phänotypen entdeckt. Eine zusätzliche Expressionsanalyse durch doppelte in situ Hybridisierung ergab eine Kolokalisierung während der Zebrafischneuroentwicklung von jeweils gfod1 und slc2a3a zusammen mit gad1b, einem Marker für GABAerge Neuronen. Interessanterweise wurden beide Risikogene zuvor mit der Glukosehomöostase und dem Energiestoffwechsel in Verbindung gebracht, die, wenn sie gestört werden, zu Veränderungen der Signalübertragung und der Lebensdauer von Neuronen führen können. Desgleichen spielt Lbx1 eine entscheidende Rolle bei der Spezifikation von GABAergen versus glutamatergenen Neuronen während der Entwicklung des Rückenmarks in der Wirbelsäule und im Hinterhirn von Mäusen und Hühnern. Vorläufige Ergebnisse dieser Arbeit deuten auf eine ähnliche Rolle beim Zebrafisch hin. Zusammengenommen stellen diese Erkenntnisse einerseits eine solide Grundlage für weitere Untersuchungen zur Funktion der Gene dar, andererseits eröffnet sich daraus die Möglichkeit neue Aspekte der ADHS-Forschung zu untersuchen, bei denen der Fokus auf der Rolle des GABAergen Neurotransmittersystems oder der Beziehung zwischen Energiestoffwechsel und psychiatrischen Erkrankungen liegt. KW - Aufmerksamkeitsdefizit-Syndrom KW - Zebrabärbling KW - ADHD KW - zebrafish KW - genes KW - behaviour KW - ADHS Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-371084 ER - TY - JOUR A1 - Zhang, Zishuai A1 - Ye, Siyu A1 - Gbureck, Uwe A1 - Barralet, Jake E. A1 - Merle, Géraldine T1 - Cavitation Mediated 3D Microstructured Architectures from Nanocarbon JF - Advanced Functional Materials N2 - Here, the formation of high surface area microscale assemblies of nanocarbon through phosphate and ultrasound cavitation treatment is reported. Despite high conductivity and large surface area, potential health and safety concerns limit the use of nanocarbon and add challenges to handling. Previously, it is shown that phosphate ultrasonic bonding is ineffective for organic materials but in this study, it is found that by a preliminary oxidizing treatment, several carbons can be readily assembled from xerogels. Assembling nanocarbon into microparticles can usually require a binder or surfactants, which can reduce surface area or conductivity and generate a low microsphere yield. Carbon nanotube microspheres are nitrogen-doped and flower-like nanostructured Pt deposited on their surface, and finally showcased as efficient cathode electrocatalysts for the oxygen reduction reaction (half-wave potential 0.78 V vs reversible hydrogen electrode) and methanol oxidation (417 mA mg−1). In particular, no significant degradation of the catalysts is detected after 12 000 cycles (26.6 h). These results indicate the potential of this multimaterial assembly method and open a new way to improve handling of nanoscale materials. KW - carbon nanotube microspheres KW - cavitation KW - oxygen reduction reaction KW - platinum nanostructures Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233926 VL - 28 ER - TY - JOUR A1 - McMaster, Rebecca A1 - Hoefner, Christiane A1 - Hrynevich, Andrei A1 - Blum, Carina A1 - Wiesner, Miriam A1 - Wittmann, Katharina A1 - Dargaville, Tim R. A1 - Bauer-Kreisel, Petra A1 - Groll, Jürgen A1 - Dalton, Paul D. A1 - Blunk, Torsten T1 - Tailored Melt Electrowritten Scaffolds for the Generation of Sheet-Like Tissue Constructs from Multicellular Spheroids JF - Advanced Healthcare Materials N2 - Melt electrowriting (MEW) is an additive manufacturing technology that is recently used to fabricate voluminous scaffolds for biomedical applications. In this study, MEW is adapted for the seeding of multicellular spheroids, which permits the easy handling as a single sheet-like tissue-scaffold construct. Spheroids are made from adipose-derived stromal cells (ASCs). Poly(ε-caprolactone) is processed via MEW into scaffolds with box-structured pores, readily tailorable to spheroid size, using 13–15 µm diameter fibers. Two 7–8 µm diameter “catching fibers” near the bottom of the scaffold are threaded through each pore (360 and 380 µm) to prevent loss of spheroids during seeding. Cell viability remains high during the two week culture period, while the differentiation of ASCs into the adipogenic lineage is induced. Subsequent sectioning and staining of the spheroid-scaffold construct can be readily performed and accumulated lipid droplets are observed, while upregulation of molecular markers associated with successful differentiation is demonstrated. Tailoring MEW scaffolds with pores allows the simultaneous seeding of high numbers of spheroids at a time into a construct that can be handled in culture and may be readily transferred to other sites for use as implants or tissue models. KW - 3D printing KW - additive manufacturing KW - adipose tissue engineering Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223921 VL - 8 ER - TY - JOUR A1 - Selcuk, Nalan Alan A1 - Toklu, Turkay A1 - Beykan, Seval A1 - Karaaslan, Serife Ipek T1 - Evaluation of the dosimetry approaches in ablation treatment of thyroid cancer JF - Journal of Applied Clinical Medical Physics N2 - In this study, we aimed to evaluate dosimetric approaches in ablation treatment of Differentiated Thyroid Carcinoma (DTC) without interrupting the clinical routine. Prior to therapy, 10.7 MBq 131I in average was orally given to 24 patients suffering from DTC. MIRD formalism was used for dosimetric calculations. For blood and bone marrow dosimetry, blood samples and whole-body counts were collected at 2, 24, 72, and 120 h after I-131 administration. For remnant tissue dosimetry, uptake measurements were performed at the same time intervals. To estimate the remnant volume, anterior and lateral planar gamma camera images were acquired with a reference source within the field of view at 24 h after I-131 administration. Ultrasound imaging was also performed. Treatment activities determined with the fixed activity method were administered to the patients. Secondary cancer risk relative to applied therapy was evaluated for dosimetric approaches. The average dose to blood and bone marrow were determined as 0.15 ± 0.04 and 0.11 ± 0.04 Gy/GBq, respectively. The average remnant tissue dose was 0.58 ± 0.52 Gy/MBq and the corresponding required activity to ablate the remnant was approximately 1.3 GBq of 131I. A strong correlation between 24th-hour uptake and time-integrated activity coefficient values was obtained. Compared to fixed activity method, approximately five times higher secondary cancer risk was determined in bone marrow dosimetry, while the risk was about three times lower in lesion-based dosimetry. KW - bone marrow dosimetry KW - remnant tissue dosimetry KW - thyroid ablation treatment Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235882 VL - 19 ER - TY - JOUR A1 - Göttlich, Claudia A1 - Kunz, Meik A1 - Zapp, Cornelia A1 - Nietzer, Sarah L. A1 - Walles, Heike A1 - Dandekar, Thomas A1 - Dandekar, Gudrun T1 - A combined tissue-engineered/in silico signature tool patient stratification in lung cancer JF - Molecular Oncology N2 - Patient-tailored therapy based on tumor drivers is promising for lung cancer treatment. For this, we combined in vitro tissue models with in silico analyses. Using individual cell lines with specific mutations, we demonstrate a generic and rapid stratification pipeline for targeted tumor therapy. We improve in vitro models of tissue conditions by a biological matrix-based three-dimensional (3D) tissue culture that allows in vitro drug testing: It correctly shows a strong drug response upon gefitinib (Gef) treatment in a cell line harboring an EGFR-activating mutation (HCC827), but no clear drug response upon treatment with the HSP90 inhibitor 17AAG in two cell lines with KRAS mutations (H441, A549). In contrast, 2D testing implies wrongly KRAS as a biomarker for HSP90 inhibitor treatment, although this fails in clinical studies. Signaling analysis by phospho-arrays showed similar effects of EGFR inhibition by Gef in HCC827 cells, under both 2D and 3D conditions. Western blot analysis confirmed that for 3D conditions, HSP90 inhibitor treatment implies different p53 regulation and decreased MET inhibition in HCC827 and H441 cells. Using in vitro data (western, phospho-kinase array, proliferation, and apoptosis), we generated cell line-specific in silico topologies and condition-specific (2D, 3D) simulations of signaling correctly mirroring in vitro treatment responses. Networks predict drug targets considering key interactions and individual cell line mutations using the Human Protein Reference Database and the COSMIC database. A signature of potential biomarkers and matching drugs improve stratification and treatment in KRAS-mutated tumors. In silico screening and dynamic simulation of drug actions resulted in individual therapeutic suggestions, that is, targeting HIF1A in H441 and LKB1 in A549 cells. In conclusion, our in vitro tumor tissue model combined with an in silico tool improves drug effect prediction and patient stratification. Our tool is used in our comprehensive cancer center and is made now publicly available for targeted therapy decisions. KW - 3D lung tumor model KW - Boolean signaling network KW - chemoresistance KW - HSP90 inhibitor KW - insilico drug screening too KW - KRAS mutation signature Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233137 VL - 12 ER - TY - JOUR A1 - Stromecki, Margaret A1 - Tatari, Nazanin A1 - Coudière Morrison, Ludivine A1 - Kaur, Ravinder A1 - Zagozewski, Jamie A1 - Palidwor, Gareth A1 - Ramaswamy, Vijay A1 - Skowron, Patryk A1 - Wölfl, Matthias A1 - Milde, Till A1 - Del Bigio, Marc R. A1 - Taylor, Michael D. A1 - Werbowetski-Ogilvie, Tamra E. T1 - Characterization of a novel OTX2-driven stem cell program in Group 3 and Group 4 medulloblastoma JF - Molecular Oncology N2 - Medulloblastoma (MB) is the most common malignant primary pediatric brain cancer. Among the most aggressive subtypes, Group 3 and Group 4 originate from stem/progenitor cells, frequently metastasize, and often display the worst prognosis, yet we know the least about the molecular mechanisms driving their progression. Here, we show that the transcription factor orthodenticle homeobox 2 (OTX2) promotes self-renewal while inhibiting differentiation in vitro and increases tumor initiation from MB stem/progenitor cells in vivo. To determine how OTX2 contributes to these processes, we employed complementary bioinformatic approaches to characterize the OTX2 regulatory network and identified novel relationships between OTX2 and genes associated with neuronal differentiation and axon guidance signaling in Group 3 and Group 4 MB stem/progenitor cells. In particular, OTX2 levels were negatively correlated with semaphorin (SEMA) signaling, as expression of 9 SEMA pathway genes is upregulated following OTX2 knockdown with some being potential direct OTX2 targets. Importantly, this negative correlation was also observed in patient samples, with lower expression of SEMA4D associated with poor outcome specifically in Group 4 tumors. Functional proof-of-principle studies demonstrated that increased levels of select SEMA pathway genes are associated with decreased self-renewal and growth in vitro and in vivo and that RHO signaling, known to mediate the effects of SEMA genes, is contributing to the OTX2 KD phenotype. Our study provides mechanistic insight into the networks controlled by OTX2 in MB stem/progenitor cells and reveals novel roles for axon guidance genes and their downstream effectors as putative tumor suppressors in MB. KW - axon guidance genes KW - medulloblastoma KW - orthodenticle homeobox 2 KW - RHO KW - semaphorin KW - stem cells Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240089 VL - 12 ER - TY - JOUR A1 - Storey, Benjamin C. A1 - Staplin, Natalie A1 - Haynes, Richard A1 - Reith, Christina A1 - Emberson, Jonathan A1 - Herrington, William G. A1 - Wheeler, David C. A1 - Walker, Robert A1 - Fellström, Bengt A1 - Wanner, Christoph A1 - Landray, Martin J. A1 - Baigent, Colin T1 - Lowering LDL cholesterol reduces cardiovascular risk independently of presence of inflammation JF - Kidney International N2 - Markers of inflammation, including plasma C-reactive protein (CRP), are associated with an increased risk of cardiovascular disease, and it has been suggested that this association is causal. However, the relationship between inflammation and cardiovascular disease has not been extensively studied in patients with chronic kidney disease. To evaluate this, we used data from the Study of Heart and Renal Protection (SHARP) to assess associations between circulating CRP and LDL cholesterol levels and the risk of vascular and non-vascular outcomes. Major vascular events were defined as nonfatal myocardial infarction, cardiac death, stroke or arterial revascularization, with an expanded outcome of vascular events of any type. Higher baseline CRP was associated with an increased risk of major vascular events (hazard ratio per 3x increase 1.28; 95% confidence interval 1.19-1.38). Higher baseline LDL cholesterol was also associated with an increased risk of major vascular events (hazard ratio per 0.6 mmol/L higher LDL cholesterol; 1.14, 1.06-1.22). Higher baseline CRP was associated with an increased risk of a range of non-vascular events (1.16, 1.12-1.21), but there was a weak inverse association between baseline LDL cholesterol and non-vascular events (0.96, 0.92-0.99). The efficacy of lowering LDL cholesterol with simvastatin/ezetimibe on major vascular events, in the randomized comparison, was similar irrespective of CRP concentration at baseline. Thus, decisions to offer statin-based therapy to patients with chronic kidney disease should continue to be guided by their absolute risk of atherosclerotic events. Estimation of such risk may include plasma biomarkers of inflammation, but there is no evidence that the relative beneficial effects of reducing LDL cholesterol depends on plasma CRP concentration. KW - C-reactive protein KW - inflammation KW - LDL cholesterol KW - randomized trials KW - vascular disease Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240067 VL - 93 ER -