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Organoids - the phenomenon of complex organ-like structures cultivation in vitro
Vilímková, Veronika ; Janečková, Lucie (advisor) ; Rothová, Olga (referee)
Pluripotent embryonal stem cells (ESCs) are unique for their ability to proliferate and differentiate into almost all cell types. In the presence of appropriate stimuli, they are able to initiate morphogenesis in vitro. Stem cells are able to differentiate into specific cell lines of a given tissue and to arrange three- dimensional (3D) structures. These so-called organoids are formed in a self-organizing process that mimics normal ESCs development. Organ development is a complex process that requires temporally and spatially ordered regulatory signals. 3D organization of these structures allows important cell-cell interactions. Organoid cultures are thus the area of a huge potential. Organoids are accessible to all standard experimental manipulations. They are therefore an ideal tool for the research of stem cells, signaling pathways, organogenesis and disease modeling. Finally, they may open up new avenues for regenerative medicine and gene therapy. Powered by TCPDF (www.tcpdf.org)
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Characterization of tumor suppressor gene Hypermethylated in cancer 1 (Hic1) and its novel target genes in the intestinal epithelium and colorectal cancer
Baloghová, Nikol ; Janečková, Lucie (advisor) ; Doubravská, Lenka (referee)
Colorectal cancer is one of the most common cancer types worldwide. Both genetic and epigenetic alterations play a critical role in its initiation and progression. One of the genes frequently epigenetically silenced or lost in many types of human cancer is tumor suppressor gene Hypermethylated in Cancer 1 (HIC1). It encodes for transcriptional repressor regulating its target genes directly or indirectly. Twelve genes whose expression is repressed by HIC1 have been identified to date. These genes encode for transcription factors, cell cycle and apoptosis regulators or proteins involved in angiogenesis as well as cell migration and invasiveness. Employing mouse embryonic fibroblasts upon Hic1-conditional knockout we have revealed six novel genes potentially repressed by Hic1 including Toll-like receptor 2 (Tlr2). Here we show that Tlr2 is one of the Hic1 target genes and that Hic1 inactivation in the intestine leads to increased Tlr2 production. Moreover, enhanced inflammatory response upon chemical-induced colitis as well as increased tumor formation in ApcMin mice was observed in Hic1-deficient mice. Expression profiling in human fibroblast upon HIC1 knockdown revealed increased expression of another potential target gene, transcription factor E2F7. Our study describes a new relationship between HIC1 and...
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Molecular mechanisms of physiological renewal and cancer transformation of mammalian gastrointestinal tissues
Stančíková, Jitka ; Kořínek, Vladimír (advisor) ; Macůrková, Marie (referee) ; Machoň, Ondřej (referee)
The plot of this PhD thesis is dedicated to investigation of the molecular pathways and events and their disruptions in the gastrointestinal tract (further abbreviated as GIT). The major role in this part plays the Wnt signaling pathway. This marvelous multipurpose machinery is responsible for epithelia renewal from stem cells (SCs) in the stomach and intestine, and for correct zonation and function of hepatic units. Of note, the Wnt pathway directs also development of embryo as well as homeostasis of many tissues apart from GIT in all metazoans, thus its flawless function is indispensable from one's origin to death. The main part of the thesis follows canonical Wnt signaling in its physiological condition and, in contrast, with pathological disturbances. This issue can be taken by variety of means as it is described in attached publications. The first publication deals with searching for new participants of Wnt signaling and their functions and describing unique markers of SCs in the intestine. Troy, the member of tumor necrosis factor receptor (TNFR) superfamily, was identified as a novel marker of intestinal SCs by probing microarray data from chromatin immunoprecipitation obtained in cultured colorectal cancer cell lines. Moreover, we found that Troy is a Wnt target gene inhibiting the...
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Organoids - the phenomenon of complex organ-like structures cultivation in vitro
Vilímková, Veronika ; Janečková, Lucie (advisor) ; Rothová, Olga (referee)
Pluripotent embryonal stem cells (ESCs) are unique for their ability to proliferate and differentiate into almost all cell types. In the presence of appropriate stimuli, they are able to initiate morphogenesis in vitro. Stem cells are able to differentiate into specific cell lines of a given tissue and to arrange three- dimensional (3D) structures. These so-called organoids are formed in a self-organizing process that mimics normal ESCs development. Organ development is a complex process that requires temporally and spatially ordered regulatory signals. 3D organization of these structures allows important cell-cell interactions. Organoid cultures are thus the area of a huge potential. Organoids are accessible to all standard experimental manipulations. They are therefore an ideal tool for the research of stem cells, signaling pathways, organogenesis and disease modeling. Finally, they may open up new avenues for regenerative medicine and gene therapy. Powered by TCPDF (www.tcpdf.org)
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Function and regulation of ETV4 and MSX1 transcription factors in colon cancer progression
Hrčkulák, Dušan ; Kříž, Vítězslav (advisor) ; Libusová, Lenka (referee)
Colon cancer causes approximately seven percent of all cancer-related deaths in the world and presumably due to modern lifestyle, it is also one of the most frequently diagnosed cancers. The inefficiency of standard treatment indicates the need for intensive research of molecular mechanisms of cancer development. The canonical Wnt signaling pathway is essential for maintenance of the progenitor phenotype of stem cells in crypts of the intestine and controls repopulation of the epithelia, in physiological conditions. However, aberrant activation leads to tumor formation. Although Wnt signaling in cancer has been subjected to thorough investigation, there is still a lot of questions concerning further branching of the pathway. As a model of Wnt/β-catenin triggered colorectal cancer, we use mice with mutated APC, which is the tumor suppressor involved in this pathway. Previous expression profiling of the intestinal tumors from relevant mice revealed two transcription factors: ETV4 and MSX1 which are significantly overexpressed in cancer cells. In this project we elucidate whether the overexpression is really tumor restricted and Wnt dependent or there is a crosstalk with another signal transduction pathway. We investigate the function and regulation of these transcription factors by synthetic reporter assays,...
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Intestinal cancer and mouse models of the disease
Baloghová, Nikol ; Janečková, Lucie (advisor) ; Gemperle, Jakub (referee)
Intestinal cancer is a serious and common disease. To understand the mechanisms of its development, it is important to know the structure of the intestinal epithelium, as well as the signalling pathways that maintain the homeostasis and regulate cell proliferation and differentiation. Development of the intestinal cancer is a multistep process in which many molecular events underlie initiation and progression of the disease. Transgenic mice produced by genetic engineering are essential tools in both research of the intestinal cancer initiation and progression and possible treatment strategies. The aim of this work is to describe the intestinal anatomy and the renewal of the intestinal epithelium including the role of multiple signalling pathways, to summarize the most common mutations conditioning human colorectal carcinoma development and to define the existing mouse models of the disease.
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Stem cells in somatic tissues of mammals - past and present view
Hlavatá, Adéla ; Kořínek, Vladimír (advisor) ; Krylov, Vladimír (referee)
The homeostatic self-renewal of tissues in the adult mammal organism is maintained by stem- cell activity. The majority of tissue-specific stem cells are dispersed in a tissue in a low number. The small intestinal epithelium is a suitable model tissue for study of the stem cells because of its regular structure and rapid self-renewal. One of the first knowledge about the intestinal stem cell characteristics was obtained from the experiments with the mice embryonal aggregation chimeras and the transgenic chimeras. There were obtained a crucial role of the Wnt signalization pathway in the control of dynamics of the stem cells and contextual coherent finding of the unique molecular marker protein of the intestinal stem cells Lgr5. Subsequently, the genetically modified mice with "reporter" genes produced from the Lgr5 locus became the main tool in the intestinal epithelial stem cell research. The views on dividing organization and particular identity of the intestinal stem cells are still controversial. keywords: stem cells, crypt base cells, intestinal epithelium, chimera, the Wnt signaling pathway, Lgr5, reporter mouse strains
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