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The role of iron in the regulation of proteins connected with tamoxifen-resistance
Potomová, Petra ; Truksa, Jaroslav (advisor) ; Balušíková, Kamila (referee)
Cancer cells are highly dependent on nutrient uptake to sustain their increased proliferation, one of these nutrients being iron. In recent years, a heightened dependency on iron was observed in cancer cells, allowing for the proper function of numerous enzymes, DNA synthesis and mitochondrial respiration. Here, we further delve into the iron metabolism of malignant cells, attempting to understand the differences between tamoxifen-sensitive and resistant (Tam5R) ones using two breast cancer cell lines of luminal A origin, MCF7 and T47D. These cells show numerous changes in iron homeostasis and iron-dependent mechanisms. Based on alterations in proteomes of Tam5R cell lines, we focused on iron regulation of proteins that are deregulated in tamoxifen resistance - assessing their regulation on transcriptional (mRNA) and post-transcriptional level (protein) as well as comparing their responsiveness to their sensitive parental cell line. We assessed two main types of regulation - iron-responsive element interaction with iron-regulatory proteins (IRE-IRP pathway) and tristetraprolin (TTP) driven mRNA degradation via AU-rich elements (ARE). Using iron loading and chelation, we challenged the cells - confirming the known IRE-IRP regulation of ferritin heavy chain (FTH), transferrin receptor 1 (TfR1),...
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Cell death as a result of iron-induced cellular damage
Běhounek, Matěj ; Balušíková, Kamila (advisor) ; Truksa, Jaroslav (referee)
Iron is an essential trace element for almost all living organisms. Iron overload in cells and tissues, however, leads to their disruption. Most oftenly damaged are parenchymatic organs such as the liver, pancreas and heart. The aim of this thesis was to create cellular in vitro models for the investigation of effects of excess iron on hepatocytes and pancreatic beta cells and on these models to investigate cellular processes which lead to cellular damage during iron overload. We focused on examining the presence of oxidative and endoplasmic reticulum stress and the activation of apoptotic cell death. For our experiments, we used HEP-G2 cell line which represents human hepatocytes and NES2Y cell line which represents human pancreatic beta cells. To study the mechanisms of cellular damage during iron overload, we used two approaches by which we observed both acute and long-term effects of high levels of iron on damage of the tested cell lines. When studying the acute effect of excess iron on the cells, we applied high doses of iron (using 15 mM ferric citrate in medium) that led to the activation of cell death in hours. Long-term effects of iron overload were tested on cells regularly cultivated in the presence of 50 μM and 100 μM ferric citrate over a period of several months. Iron concentrations...
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Extracellular microRNAs and their role in pathologies especially in the field of gynecology and obstetrics.
Štěrbová, Monika ; Hromadníková, Ilona (advisor) ; Balušíková, Kamila (referee)
microRNAs (miRNAs) represent a relatively newly discovered group of RNA molecules and they serve to regulate gene expression. In spite of processes of differentiation, proliferation and apoptosis, miRNAs influence the whole biological systems, such as embryogenesis, oncogenesis, and immunity. There have been a number of experiments in recent years concerning diagnoses and predictions of complications during pregnancy, and tumour growth. Extracellular miRNA molecules participating in circulation of patients are used in the non-invasive diagnostics. RNA molecules usually get into the extracellular fluid during the apoptosis process. I chose four diseases, which extracellular miRNA have diagnostic potential - preeclampsia, intrauterine growth retardation, gestational diabetes mellitus and breast cancer - for my work. An aberrant expression of different levels of various extracellular miRNAs has been reported in these diseases but the clinical use of microRNAs in the diagnosis and prediction of those still requires further research and optimization. Keywords: breast cancer, extracellular nucleic acids, fetal growth retardation, gestational diabetes mellitus, microRNA, PCR, preeclampsia
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Molecular mechanisms of iron transport across plasma membrane in mammalian cells
Balušíková, Kamila ; Kovář, Jan (advisor) ; Ehrmann, Jiří (referee) ; Krijt, Jan (referee)
Iron belongs among the trace elements and its role in humans is irreplaceable. Up to 5 g of iron can be found in adult body distributed among different compounds. Iron ions are therefore essential to all cells of our body and its homeostasis is thoroughly controlled. Iron uptake into the organism is mediated by enterocyte cells in the small intestine, where heme as well as non-heme forms of iron are absorbed. Non-heme iron is absorbed via Dcytb (duodenal cytochrome b), DMT1 (divalent metal transporter 1), ferroportin, hephaestin, and ceruloplasmin molecules. Although these molecules can also participate in non-transferrin- bound iron transport across plasma membranes within the whole organism, mechanisms of this transport are not yet fully elucidated. The aim of the present work was to contribute to our understanding of molecular mechanisms that are involved in non-transferrin-bound iron transport across the plasma membrane of mammalian cells. Our project was focused on the description of non-transferrin- bound iron transport in human cells in vitro and in vivo under conditions of iron deficiency or iron overload. Transformed cell lines, that represent the three main types of cells involved in iron homeostasis, and tissue samples of duodenal biopsies were used as experimental models. The expression...
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Effect of the availability of iron compounds on the expression of molecules involved in the transport of non-transferrin iron ions: In vitro study concerning human cell lines K562 and Caco-2
Balušíková, Kamila
Iron absorption, transport, and storage in the body is very strictly regulated mechanism by the reason of absence of a controlled pathway provided its excretion. Hence we are interested in transport mechanism of non-haem iron which is mediated by molecules DMT1 (divalent metal transporter 1, membrane iron importer), Dcytb (duodenal cytochrom b, membrane ferrireductase), ferroportin 1 (membrane iron exporter), hephaestin (membrane ferroxidase) and ceruloplasmin (cytoplasmatic ferroxidase) and enable iron uptake from food up to its binding to plasma transferrin. Our project monitors the effect of iron availability to the expression of the molecules potentially involved in non-transferrin iron transport across cell membranes. We studied the influence of iron deficiency and iron overload to the regulation of iron uptake by these molecules in various functional types of human cells. Cells were maintained in RPMI 1640 medium and supplemented with other additives. The expression was tested on mRNA level by quantitative real-time PCR with reverse transcription in in vitro study using human cell lines K562 and Caco-2. K562 cells (human erythroleukemia) represent cells with high utilization of no-transferrin iron and Caco-2 cells (human colorectal carcinoma) is a model of cells with different apical and...
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Molecular mechanisms of iron transport across plasma membrane in mammalian cells
Balušíková, Kamila ; Kovář, Jan (advisor) ; Ehrmann, Jiří (referee) ; Krijt, Jan (referee)
Iron belongs among the trace elements and its role in humans is irreplaceable. Up to 5 g of iron can be found in adult body distributed among different compounds. Iron ions are therefore essential to all cells of our body and its homeostasis is thoroughly controlled. Iron uptake into the organism is mediated by enterocyte cells in the small intestine, where heme as well as non-heme forms of iron are absorbed. Non-heme iron is absorbed via Dcytb (duodenal cytochrome b), DMT1 (divalent metal transporter 1), ferroportin, hephaestin, and ceruloplasmin molecules. Although these molecules can also participate in non-transferrin- bound iron transport across plasma membranes within the whole organism, mechanisms of this transport are not yet fully elucidated. The aim of the present work was to contribute to our understanding of molecular mechanisms that are involved in non-transferrin-bound iron transport across the plasma membrane of mammalian cells. Our project was focused on the description of non-transferrin- bound iron transport in human cells in vitro and in vivo under conditions of iron deficiency or iron overload. Transformed cell lines, that represent the three main types of cells involved in iron homeostasis, and tissue samples of duodenal biopsies were used as experimental models. The expression...
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Cell death as a result of iron-induced cellular damage
Běhounek, Matěj ; Balušíková, Kamila (advisor) ; Truksa, Jaroslav (referee)
Iron is an essential trace element for almost all living organisms. Iron overload in cells and tissues, however, leads to their disruption. Most oftenly damaged are parenchymatic organs such as the liver, pancreas and heart. The aim of this thesis was to create cellular in vitro models for the investigation of effects of excess iron on hepatocytes and pancreatic beta cells and on these models to investigate cellular processes which lead to cellular damage during iron overload. We focused on examining the presence of oxidative and endoplasmic reticulum stress and the activation of apoptotic cell death. For our experiments, we used HEP-G2 cell line which represents human hepatocytes and NES2Y cell line which represents human pancreatic beta cells. To study the mechanisms of cellular damage during iron overload, we used two approaches by which we observed both acute and long-term effects of high levels of iron on damage of the tested cell lines. When studying the acute effect of excess iron on the cells, we applied high doses of iron (using 15 mM ferric citrate in medium) that led to the activation of cell death in hours. Long-term effects of iron overload were tested on cells regularly cultivated in the presence of 50 μM and 100 μM ferric citrate over a period of several months. Iron concentrations...
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