Global ETD Search

11	Avaliação da terapia fotodinâmica em um modelo tumoral em membrana corioalantóica / Evaluation of Photodynamic Therapy in a tumor model on the chorioallantoic membrane Hilde Harb Buzzá 02 March 2016 (has links) A Terapia Fotodinâmica (TFD) é um tratamento alternativo de câncer que vem tendo grandes avanços ao longo dos anos e consiste na interação entre luz e uma substância fotossensibilizadora, levando à transformação do oxigênio molecular em oxigênio singleto, altamente reativo e tóxico para a célula. Nesse contexto, o uso do modelo de Membrana Corioalantóica (CAM, do inglês Chorioallantoic Membrane) fornece acesso direto aos vasos sanguíneos, possibilitando o estudo dos efeitos vasculares envolvidos nessa terapia. O desenvolvimento de um tumor nesse ambiente previamente vascularizado permite o estudo e o entendimento dos mecanismos que envolvem o crescimento e destruição do tumor, levando ao aperfeiçoamento de diferentes modalidades terapêuticas. As células tumorais empregadas para o desenvolvimento do tumor podem ser de diversas linhagens e formas de aplicação, desde culturas celulares a biópsias tumorais. O objetivo principal foi investigar a terapia fotodinâmica nos vasos e nas células neoplásicas em um modelo de tumor em CAM. Com esse modelo estudado para células tumorais de melanoma e Ehrlich, foi escolhido trabalhar com tumor de Erlich pela facilidade de manuseio laboratorial. Por meio da microscopia confocal de fluorescência, foi observada a interação entre os vasos sanguíneos e as células tumorais. Com imagens por fluorescência, foi possível entender e quantificar o efeito individualizado dos fotossensibilizadores, incluindo a farmacodinâmica do Photogem® e da formação da protoporfirina IX a partir do ALA, tanto com aplicação tópica como intravenosa. A partir disso, o tumor foi irradiado e os efeitos da terapia fotodinâmica foram analisados tanto no tumor quanto nos vasos sanguíneos que o alimentam. Usando ainda a curcumina, um fotossensibilizador derivado do açafrão, que sozinho possui um efeito vascular, foi aplicada a Terapia Fotodinâmica para análise na membrana corioalantóica e efeito nos vasos sanguíneos. O entendimento desse efeito da curcumina permite a ampliação de seu uso como fotossensibilizador no tratamento de câncer e doenças vasculares. Portanto, com o modelo estabelecido foi possível acompanhar os fotossensibilizadores estudados tanto nos vasos sanguíneos e sua ação, como a diferente atuação no ambiente tumoral, causando dano às células do tumor e aos vasos sanguíneos do mesmo ambiente. / Photodynamic Therapy (PDT) is a cancer treatment that has had great advances over the years and consists in the interaction between light and a photosensitizer compound, transforming the molecular oxygen in singlet oxygen, highly reactive and toxic to the cell. In this context, the use of Chorioallantoic Membrane (CAM) enables direct access to blood vessels, making possible to study the vascular effects involved in this therapy. The development of a tumor in this environment previously vascularized allows the study and the understanding of mechanisms that involves the growing and the destruction of tumor, improving different therapeutic modalities. The tumor cells used to develop the tumor in this model can be from several lines and ways of application, since cell culture to biopsy of some tumor. The main objective was investigating PDT in blood vessels and neoplasic cells in the tumor model in CAM. With this model studied for melanoma cells and Ehrlich, it was chosen to work with Ehrlich tumor because its facility of laboratory manipulation. After the observation the interaction between blood vessels and tumor cells, with confocal microscopy analysis, it was possible to understand and quantify the individualized effect of photosensitizers, including the pharmacodynamic of Photogem® and the Protoporphyrin IX from Aminolevulinic acid, both topic and intravenous application. From this, the tumor was illuminated and the Photdynamic Therapy effects was analyzed both tumor and blood vessels that feeds it. Still using the curcumin, photosensitizer derivated of saffron which has alone a vascular effect, was applied PDT to analysis on the Chorioallantoic Membrane and the blood vessels effect. The understanding of this effect of curcumin enables the extension of its useful as photosensitizer in the cancer treatment and vascular diseases. Therefore, with the model established, it was possible to follow all PS studying both their action in blood vessels and in the tumor region, causing damage. Efeito vascular Membrana corioalantóica Modelo tumoral PDT Terapia fotodinâmica Chorioallantoic membrane PDT Photodynamic therapy Tumor model Vascular effect
12	From Mouse Mammary Tumor Model to New Therapeutic Method ---Mammary Tumor Development in Balb/c-Trp53+/- Mice and Magnetic Nanoparticle Induced Heating for Cancer Treatment Yan, Haoheng 01 May 2010 (has links) Mutation and loss of p53 function are common features among human breast cancers. We use BALB/c-Trp53+/- mice as a model to examine the sequence of events leading to mammary tumors. Mammary epithelium proliferation rates were similar in both BALB/c-Trp53+/- mice and wild type controls. Among the 28 mammary tumors collected from BALB/c-Trp53+/- mice, loss of heterozygosity for Trp53 was detected in more than 90% of invasive mammary tumors. Transplantation of Trp53+/- ductal hyperplasias indicated an association between loss of the wild type allele of Trp53 and progression to invasive carcinomas. Expression of biomarkers such as ERα, PR, Her2/Neu and activated Notch1 varied among the tumors suggesting that multiple oncogenic events collaborate with loss of p53 function. The majority of the tumors expressed both luminal and basal cytokeratins (59%). Gene expression analysis showed ligands and receptors of stem cell related pathways, such as Notch and Wnt, were increased in the tumors. These results indicate that mammary tumors in BALB/c Trp53+/- mice might initiate from bipotent mammary progenitor cells. USING MAGNETIC NANOPARTICLES FOR CANCER THERMOTHERAPY Alternating magnetic field (AMF) heating of magnetic nanomaterials provides a promising method for executing therapeutic thermal treatment for cancer patients. In order to explore the potential of magnetic nanoparticles (MNPs) for hyperthermia treatment, we synthesized iron oxide MNPs with various passivation by citric acid, folate, trimethylamine carboxylic acid, or albumin. The albumin passivated MNP (MNP-A) surpassed other MNPs, showing efficient heating with very low inherent cytotoxicity. Confocal microscopy located MNP-A (FITC tagged) accumulation in both cell nucleus and cytosol after 24hr incubation with HeLa cells. The quantity of cell bound MNP-A (including internalized and cell membrane bound MNP-A) was positively associated with MNP-A concentration and incubation time with cells. The MNP-A bound to cells was sufficient to increase the temperature in the cell pellet Δ7°C after 8min exposure to AMF. No significant temperature increase or cell death was detected in control groups. Our data demonstrate that MNP-A provides a selective tool for AMF-induced thermal treatment, as well as useful dosing information for future preclinical animal studies. Breast cancer Magnetic nanoparticle Mammary gland Mouse tumor model Stem cell Thermotherapy Cell and Developmental Biology Cell Biology
13	Lyz2-Cre-Mediated Genetic Deletion of Septin7 Reveals a Role of Septins in Macrophage Cytokinesis and Kras-Driven Tumorigenesis Menon, Manoj B., Yakovleva, Tatiana, Ronkina, Natalia, Suwandi, Abdulhadi, Odak, Ivan, Dhamija, Sonam, Sandrock, Inga, Hansmann, Florian, Baumgärtner, Wolfgang, Förster, Reinhold, Kotlyarov, Alexej, Gaestel, Matthias 03 April 2023 (has links) By crossing septin7-floxed mice with Lyz2-Cre mice carrying the Cre recombinase inserted in the Lysozyme-M (Lyz2) gene locus we aimed the specific deletion of septin7 in myeloid cells, such as monocytes, macrophages and granulocytes. Septin7flox/flox:Lyz2-Cre mice show no alterations in the myeloid compartment. Septin7-deleted macrophages (BMDMs) were isolated and analyzed. The lack of Septin7 expression was confirmed and a constitutive double-nucleation was detected in Septin7-deficient BMDMs indicating a defect in macrophage cytokinesis. However, phagocytic function of macrophages as judged by uptake of labelled E. coli particles and LPS-stimulated macrophage activation as judged by induction of TNF mRNA expression and TNF secretion were not compromised. In addition to myeloid cells, Lyz2-Cre is also active in type II pneumocytes (AT2 cells). We monitored lung adenocarcinoma formation in these mice by crossing them with the conditional knock-in Kras-LSL-G12D allele. Interestingly, we found that control mice without septin7 depletion die after 3–5 weeks, while the Septin7-deficient animals survived 11 weeks or even longer. Control mice sacrificed in the age of 4 weeks display a bronchiolo-alveolar hyperplasia with multiple adenomas, whereas the Septin7-deficient animals of the same age are normal or show only a weak multifocal brochiolo-alveolar hyperplasia. Our findings indicate an essential role of Septin7 in macrophage cytokinesis but not in macrophage function. Furthermore, septin7 seems absolutely essential for oncogenic Kras-driven lung tumorigenesis making it a potential target for anti-tumor interventions. info:eu-repo/classification/ddc/570 ddc:570
14	Identification de cibles diagnostiques et thérapeutiques potentielles pour l’adénocarcinome canalaire pancréatique dans un nouveau modèle chez l’embryon de poulet Dumartin, Laurent 15 December 2008 (has links) L’Adénocarcinome Canalaire Pancréatique (ACP), la forme majeure de cancer du pancréas, est un des cancers les plus mortels du fait de son agressivité d’invasion locale et de dissémination vasculaire et de l’absence de méthode de détection précoce de la maladie. Nous avons développé un nouveau modèle d’invasion in vivo, sur la membrane chorio-allantoïdienne de l’embryon de poulet, permettant d’analyser les mécanismes d’interactions entre les cellules tumorales pancréatiques et leur microenvironnement. Nous avons montré que dans ce modèle les gènes codant pour les protéines sécrétées nétrine-1 et CXCL4L1/PF4v1 sont surexprimés dans les cellules tumorales au cours du processus d’invasion et que cette surexpression est également retrouvée dans les échantillons de patients humains. Nos études fonctionnelles ont indiqué que la nétrine-1 et CXCL4L1 pourrait jouer le rôle de régulateurs de la progression tumorale selon le modèle suivant : a) la chimiokine CXCL4L1 exercerait de façon paracrine une activité angiostatique sur les cellules endothéliales de l’ACP alors que b) la nétrine-1 aurait une activité pro-tumorale en agissant à la fois sur les cellules tumorales et sur les cellules endothéliales. Ces résultats ont permis d’une part de valider notre modèle en confirmant que les gènes surexprimés sélectionnés peuvent être impliqués dans la progression tumorale chez les patients. D’autre part, notre étude a permis de démontrer que les protéines CXCL4L1 et nétrine-1 constituent de nouvelles cibles thérapeutiques et/ou diagnostiques potentielles pour le cancer du pancréas. / Pancreatic Ductal Adenocarcinoma (PDAC), the major form of pancreatic cancer, is one of the deadliest cancers because of its propensity for local invasion and vascular dissemination and the lack of early diagnostic strategy. We have developed a new in vivo invasion model, on the chick embryo chorioallantoic membrane, allowing the analyze of mechanisms governing interactions between pancreatic tumor cells and their host microenvironment. We showed in its model that the genes encoding netrin-1 and CXCL4L1/PF4v1 secreted proteins are up-regulated in tumor cells in the course of the invasion process and we confirmed these up-regulation was also observed in human patients. Our functional studies indicated that netrin-1 and CXCL4L1 may play regulator roles in tumor progression according to the following model: a) CXCL4L1 chimiokine may have an angiostatic activity on endothelial cells by a paracrine mechanism of action whereas b) netrin-1 may have a pro-tumoral activity by acting on both endothelial and tumor cells. These results allowed in one hand to validate our model by showing that selected up-regulated genes may be involved in PDAC progression in human patients. On the other hand, our work provided evidence that CXCL4L1 and netrin-1 constitute new potential therapeutic and/or diagnostic targets for pancreatic cancer. Cancer du pancréas Marqueurs diagnostiques Invasion CXCL4L1 / PF4v1 Transcriptome Interactions tumeur - stroma Nétrine-1 Apoptose Membrane chorio-allantoïdienne Cibles thérapeutiques Angiogenèse Modèle tumoral Diagnostic markers CXCL4L1 / PF4v1 Netrin-1 Therapeutic targets Pancreatic cancer Tumor model Chorioallantoic membrane Tumor - stroma interactions Invasion Angiogenesis Apoptosis Transcriptome
15	Cell type-dependent differential activation of ERK by oncogenic KRAS or BRAF in the mouse intestinal epithelium Brandt, Raphael 10 March 2023 (has links) Kolorektale Karzinome (CRC) zeigen eine heterogene Ätiologie. Die Progression prämaligner Vorläufer zu CRC unterscheidet (U) sich in Morphologie, molekularen Veränderungen und Interaktion mit der Tumorumgebung. CRC weisen oft onkogene Mutationen in KRAS und BRAF auf. Diese steigern die MAPK Signalwegaktivität (Mpa). Obwohl sie im selben Signalweg wirken, sind KRAS und BRAF auf die CRC-Entitäten U verteilt. Dabei ist KRAS häufiger im sogenannten konventionellen und BRAF im serratierten Weg zu CRC mutiert. In dieser Studie nutzte ich murine intestinale Organoide (iO), die induzierbare (Ind) KRAS oder BRAF Onkogene exprimieren. Große U zwischen KRAS und BRAF zeigten sich sowohl in Signaltransduktion (ST) als auch im Phänotyp. Phosphoprotein-, ERK-Reporter-, scRNA-Seq und EM-Analysen ergaben eine starke Mpa durch BRAF, die zu hoher Expression von MAPK-Zielgenen und Verlust der epithelialen Integrität führte. iO nach KRAS-Ind blieben intakt, korrelierend mit moderater, zelltypspezifischer (ZS) Mpa in sekretorischen und undifferenzierten Zellen. Die meisten Enterozyten waren Mpa-negativ. ERK-Reporter zeigten: Das ZS Muster der Mpa ist nicht nur gegenüber KRAS, sondern auch dem Entzug von Wachstumsfaktoren stabil. Dies spricht für eine intrinsische, robuste Regulierung der Mpa. BRAF-Ind Mpa setzte die ZS Regulierung der MAPK außer Kraft und schädigte das Gewebe, im Einklang mit einer oberen Grenze tolerabler Mpa. Die ZS Mpa wurde in CRC-Zelllinien bestätigt, deren Mpa durch KRAS aber nicht BRAF U ausfiel. Ferner, nutzte ich iO mit bCatenin+KRAS-Ind, um den konventionellen Weg zu CRC zu modellieren. Die Kombination führte zu synergistischen Effekten, die sich in EGFR-unabhängigem Wachstum und der Aufhebung der ZS Mpa-Blockade äußerten, die durch eine Verschiebung der Differenzierung zu mehr Progenitorzellen bewirkt wurde. Zusammenfassend konnte ich U in der Mpa durch KRAS oder BRAF im Darmepithel feststellen, was dazu beiträgt, deren Rollen in der CRC-Genese zu bestimmen. / Colorectal cancer (CRC) is a disease with heterogeneous etiology. Premalignant lesions follow distinct routes of progression to carcinoma reflected by differences in morphology, molecular alterations and the tumor environment. Mutant KRAS and BRAF are frequent, leading to MAPK pathway activation (Mpa), which is relevant for CRC therapy. Despite acting in the same pathway, mutant KRAS and BRAF segregate to different entities, as KRAS is more frequent in the conventional- and BRAF being specific for the serrated route to CRC. I used murine intestinal organoids (iO) expressing inducible oncogenic KRAS or BRAF to study the impact of oncogenes in primary cells. I found marked differences in signal transduction and phenotype. Phospho-protein, ERK-reporter, scRNA-seq and EM data showed strong Mpa upon BRAF induction followed by ERK-target gene expression leading to tissue disruption. In contrast, KRAS left the tissue intact resulting in less and cell type-dependent Mpa limited to secretory cells, a subset of late-stage enterocytes and undifferentiated crypt cells. Most enterocytes were irresponsive to KRAS. The pattern of Mpa was robust towards KRAS or growth factor depletion arguing in favor of intrinsic, resilient MAPK regulation. In iO, BRAF-induced Mpa could break this cell type-specific regulation, indicating an upper limit of tolerable Mpa. I validated these findings in CRC cell lines that differed in Mpa in response to oncogenic KRAS but not BRAF. Finally, I used iO expressing an inducible form of stabilized bCatenin in combination with KRAS to mimic events frequently found in the conventional pathway to CRC. Expression of KRAS and bCatenin synergized in driving EGFR independent growth and breaking the villus-specific block of Mpa by altering differentiation towards progenitor cell types. In summary, this study emphasizes differences between Mpa induced by oncogenic KRAS or BRAF which helps clarifying their nature in different etiological routes to CRC genesis. KRAS KRASG12V BRAF BRAFV600E EGFR EGF MAPK ERK FIRE Reporter MEK MAPKK MAPKKK beta-Catenin intestinale Organoidkultur intestinale Organoide Mausmodelle von Tumoren kolorektales Karzinom kolorektale Karzionome CRC Primärzellen Tumormodelle Onkogene oncogenes KRAS oncogenes BRAF onkogene Signaltransduktion 3D Modell matrigel R-spondin RSPO Noggin KRAS KRASG12V BRAF BRAFV600E EGFR EGF MAPK ERK FIRE reporter MEK MAPKK MAPKKK beta-Catenin intestinal organoid intestinal organoids intestinal organoid culture murine model of cancer colorectal carcinoma CRC primary tumor model oncogenes oncogenic KRAS oncogenic BRAF 3D model matrigel R-spondin RSPO Noggin 610 Medizin und Gesundheit ddc:610

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