National Repository of Grey Literature 4 records found  Search took 0.00 seconds. 
Mechanisms of resistance and iron metabolism in cancer stem cells
Lettlová, Sandra
(EN) Analogously to normal stem cells within the tissues, cancer stem cells (CSCs) have been proposed to be responsible for maintenance and growth of tumours. CSCs represent a small fraction of cells within the tumour, which is characterised by self-renewal capacity and ability to give rise to a tumour when grafted into immunocompromised mice. Cells with increased stemness properties are believed to be responsible for tumour resistance, metastases formation and relapse after tumour treatment. The first part of this work concentrates on resistance of the tumours, which is often associated with increased expression of ATP-binding cassete (ABC) transporters pumping chemotherapeutics out of the cells. For the purposes of this study, we utilized an in vitro model of CSCs, based on cultivation of cells as 3D "spheres". Expression profiling demonstrates that our model of CSCs derived from breast and prostate cancer cell lines express higher mRNA level of ABC transporters, particularly ABCA1, ABCA3, ABCA5, ABCA12, ABCA13, ABCB7, ABCB9, ABCB10, ABCC1, ABCC2, ABCC3, ABCC5, ABCC8, ABCC10, ABCC11 and ABCG2 among the cell lines tested. The protein level of ABC transporters tested in breast CSCs showed higher expression of ABCB8, ABCC1, ABCC2, ABCC10 and ABCG2 but downregulation of ABCB10 and ABCF2 proteins....
Mechanisms of resistance and iron metabolism in cancer stem cells
Lettlová, Sandra ; Truksa, Jaroslav (advisor) ; Kovář, Jan (referee) ; Brábek, Jan (referee)
(EN) Analogously to normal stem cells within the tissues, cancer stem cells (CSCs) have been proposed to be responsible for maintenance and growth of tumours. CSCs represent a small fraction of cells within the tumour, which is characterised by self-renewal capacity and ability to give rise to a tumour when grafted into immunocompromised mice. Cells with increased stemness properties are believed to be responsible for tumour resistance, metastases formation and relapse after tumour treatment. The first part of this work concentrates on resistance of the tumours, which is often associated with increased expression of ATP-binding cassete (ABC) transporters pumping chemotherapeutics out of the cells. For the purposes of this study, we utilized an in vitro model of CSCs, based on cultivation of cells as 3D "spheres". Expression profiling demonstrates that our model of CSCs derived from breast and prostate cancer cell lines express higher mRNA level of ABC transporters, particularly ABCA1, ABCA3, ABCA5, ABCA12, ABCA13, ABCB7, ABCB9, ABCB10, ABCC1, ABCC2, ABCC3, ABCC5, ABCC8, ABCC10, ABCC11 and ABCG2 among the cell lines tested. The protein level of ABC transporters tested in breast CSCs showed higher expression of ABCB8, ABCC1, ABCC2, ABCC10 and ABCG2 but downregulation of ABCB10 and ABCF2 proteins....
The role of Hippo Signalling pathway in tumor cell metabolism
Lettlová, Sandra ; Stiborová, Marie (advisor) ; Dračínská, Helena (referee)
Vitamine E analogues α-tocopheryl succinate (α-TOS) and mitochondrially targeted vitamine E succinate (MitoVES) are anti-cancer agents from the group of "mitocans", the compounds acting via mitochondria which present a promising invariant target for cancer cell therapy. α-TOS and MitoVES induce apoptosis selectively in various cancer cell types involving generation of reactive oxygen species (ROS). Generated superoxid anion radicals in response to α-TOS and MitoVES are believed to be converted into hydrogen peroxide that is known to activate Mammalian sterile 20-like kinase (Mst1), the central component of Hippo signalling pathway, that presents an universal size control mechanism in all metazoans and its deregulation is linked to tumourigenesis. MitoVES and α-TOS were both reported to activate Mst1 that phosphorylates Forkhead box O1 (FoxO1) transcription factor resulting in its transport to nucleus where induce the expression of pro-apoptotic genes, including NOXA, and thus promote apoptosis. The target of Hippo signalling pathway is transcriptional co- activator Yes-associated protein (Yap) which was found in Drosophila melanogaster to regulate the expression of transcription factor c-Myc which is known as the most prominent human oncogene. This thesis focused on involvement of Hippo signalling...
Úloha Mst1 / FoxO dráhy při indukci apoptosy
Lettlová, Sandra ; Bezouška, Karel (advisor) ; Liberda, Jiří (referee)
Vitamin E analogue -tocopheryl succinate (-TOS) from the group of mitocans, the drugs targeting mitochondria, is a selective inducer of apoptosis in various cancer cell types, which involves the accumulation of reactive oxygen species (ROS). It was found that ROS generation causes p53-independent upregulation of the pro-apoptotic protein Noxa that induces apoptosis by displacement of the BH3-only protein Bak from its inactive complex with the anti-apoptotic protein Mcl-1 to form a pore in outer mitochondrial membrane. Current research has demonstrated that generation of ROS causes activation of Mst1, a component of the Hippo pathway that presents a universal size-control mechanism in all metazoans, whose deregulation is linked to tumorigenesis. Treatment of Jurkat cells with - TOS revealed that activated Mst1 kinase phosphorylates the Forkhead box O1 (FoxO1) transcription factor that then translocates to the nucleus and activates transcription of genes important for apoptosis induction, including NOXA. This explains the p53 independent apoptosis induction and presents Mst1-FoxO1-Noxa as a new pathway involved in the process. Current research has also documented that activated Mst1 kinase controls the expression of the c-MYC oncogene and its target genes, whose products are involved in glucose...

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