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Induction and course of programmed cell death in cancer cells after taxane application."
Kábelová, Adéla ; Jelínek, Michael (advisor) ; Gemperle, Jakub (referee)
The taxanes are a class of commonly used anticancer agents, which are very effective in treatment of breast, ovarian, prostate or lung cancer. Taxanes bind to the β-tubulin subunit of microtubules and lead to their stabilization and inhibition of depolymerization. Such microtubules lose their function to form mitotic spindle, thus arresting cells in G2/M phase and resulting in apoptosis. Unfortunately some cells are able to escape from taxanes-induced apoptosis by developing various mechanisms of resistance including alteration in taxanes target microtubules or upregulation of specific transporters that pump the drug out of cells. Other types of resistance are connected with process of programmed cell death (PCD), especially with proteins that after taxane application participate in its successful progress. Taxanes can directly or indirectly modify the activity of Bcl-2-family proteins that control mitochondrial and endoplasmic reticulum integrity, thus regulating the initiation of PCD. Caspases are executioners of PCD and caspase-2 activated by cytoskeletal disruption seems to be especially important in taxanes- induced apoptosis. In some cases can taxane treatment also result in caspase-independent cell death. Special role has protein p53 that seems to be involved only in apoptosis caused by low taxanes...
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Cytochrome c and its role in apoptosis
Rajsiglová, Lenka ; Kalous, Martin (advisor) ; Švadlenka, Jan (referee)
Cell energetic metabolism and cell survival are strictly controlled by pathways in which cytochrome molecules play a central role, in particular cytochrome c. It is localized in the mitochondrial intermembrane space with other molecules cooperating in keeping energetic metabolism. Permeabilization of outer mitochondrial membrane by proteins from Bcl-2 family or changes in Ca2+ levels causes cytochrome c release into cytosol. In cytosol cytochrome c interacts with other pro-apoptotic proteins (Apaf-1, procaspase-9) cooperating to form apoptosome and phosphatidylserine. As a result of these interactions, the cell is going to apoptosis. This bachelor thesis summarizes the current state of knowledge of these processes. In the first part it focuses on the biosynthesis of cytochrome c, further on the mechanisms of its releasing from mitochondria and its interactions with other proteins within apoptosis including options of regulation of these processes.
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The role of fatty acids in apoptosis induction in pancreatic beta cells
Žigová, Ivana ; Němcová, Vlasta (advisor) ; Libusová, Lenka (referee)
Type 2 diabetes belongs to lifestyle diseases. To its development contributes also the decrease in functional cell mass caused particularly by long-term action of increased blood levels of fatty acids and glucose. Experiments from recent years demonstrated that apoptosis of pancreatic cells is induced especially by saturated fatty acids, in contrast to unsaturated fatty acids which do not exert significant cytotoxic effect and they are even able to inhibit the proapoptotic effect of saturated fatty acids. Despite intensive research, the mechanisms of fatty acid-induced apoptosis of pancreatic cells are not convincingly explained. Understanding of the processes that lead to destruction of functional cells could enable development of new therapies for type 2 diabetes treatment that would be targeted directly at one of the causes of this disease. The aim of this work is to summarize the recent knowledge about mechanisms by which fatty acids induce and regulate apoptosis of pancreatic cells.
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The role of autophagy in apoptosis induction by fatty acids in pancreatic beta cells.
Žigová, Ivana ; Němcová, Vlasta (advisor) ; Truksa, Jaroslav (referee)
Type 2 diabetes mellitus represents a metabolic disease reaching epidemic dimensions in the 21st century. Fatty acid-induced apoptosis of pancreatic β-cells significantly contributes to its pathogenesis. Saturated fatty acids (FAs) are strongly cytotoxic for β-cells, whereas unsaturated FAs are well tolerable by β-cells, they are even able to inhibit proapoptotic effects of saturated FAs when co-incubated. According to recent studies, FAs-induced apoptosis in pancreatic β-cells is partly regulated by autophagy, a catabolic process involved in the degradation and recyclation of cell components in lysosomes. The aim of this diploma thesis was to contribute to the clarification of the role of autophagy in FAs-induced apoptosis regulation. We induced apoptosis in human pancreatic β- cell line NES2Y by 1 mM stearic acid (SA) and inhibited it with 0.2 mM oleic acid (OA) co- incubated with SA. We revealed, that the saturated SA used in apoptosis-inducing concentration simultaneously inhibits the autophagic flux in pancreatic NES2Y cell line. When SA is co- incubated with unsaturated OA in concentration sufficient for inhibition of proapoptotic effect of SA, OA is also able to inhibit the block of autophagy induced by the effect of SA. Application of unsaturated OA alone in this concentration did not...
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Caspase-8 - a multifunctional protease at the intersection of apoptosis and necrosis
Davídková, Daniela ; Anděra, Ladislav (advisor) ; Doubravská, Lenka (referee)
Caspase-8 is classified as an initiator caspase especially of death receptors-induced apoptosis. It is expressed in all tissues and depending on its regulatory circuits it plays an important role not only in the signalization of apoptosis but also in necroptosis, cell survival and other cellular processes. Its proper function is irreplaceable in general proliferation, differentiation and development, in the function of immune responses and thus maintenance of homeostasis. Its malfunction or absence is manifested by defects in both cells and organisms and it is connected with serious diseases such as cancer. This thesis summarizes the knowledge of ways of regulation and function of caspase-8 in these processes. Key words: caspases, apoptosis, necrosis, necroptosis, DISC, activation complex
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Molecular mechanism of MST1 kinase activation in cancer cells
Smetanová, Jitka ; Vališ, Karel (advisor) ; Grobárová, Valéria (referee)
MST1 kinase is an internal part of the Hippo signal pathway. The Hippo pathway is an evolutionary conserved regulator of tissue and organ growth and affects proliferation and apoptosis. Active MST1 kinase phosphorylates YAP and TAZ oncoproteins, which regulate the activity of transcription factors in their unphosphorylated state, including TEAD and SMAD. Furthermore active MST1 kinase phosphorylates FOXO transcription factors and induces their translocation into the cell nucleus. Finally the activation of MST1 kinase leads to cell apoptosis or halt cell cycle in G1 phase. Activation of MST1 protein depends on its auto-phosphorylation and cleavage. Recently, there are several articles which take interest in the issue of activation of MST1. Some of them describe the activation of MST1 by the effector caspase-3 and -7, on the other hand the latest articles argue that MST1 kinase itself is responsible for the activation of caspases. The molecular mechanism of MST1 kinase activation was studied in this bachelor thesis. We used the biologically active compounds GDC-0941 for the activation of MST1 protein. The activity of caspase was inhibited by specific inhibitor Z-DEVD. Using electrophoresis and Western blot it was demonstrated that MST1 is active in the case when caspases are inhibited. This fact...
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Activation of the initiation caspases and regulation of their activity
Votavová, Barbora ; Anděra, Ladislav (advisor) ; Černý, Jan (referee)
Caspases are the key proteins participating in both activation and execution of apoptosis. Extrinsic or intrinsic apoptotic signaling leads to sequential activation of the initiation and execution caspases. Activation of initiator caspases is mediated by their processing in multiprotein complexes and activated initiator caspases then specifically cleave and thus activate the effector caspases. These then cleave a number of structural and functional proteins, which consequently leads to cellular selfdestruction and its breakdown to apoptotic bodies. Considering the fundamental significance of the initiation of apoptosis, the activation as well as the activity of initiator (but also effector) caspases is strictly regulated at several levels. Primary the intensity and character of the recieved signal is crucial for the effective formation of the caspase activation complex. Then the concentration of intracellular ionts, nucleotides and various proteins (proteins from the Bcl-2 family, inhibitors of apoptosis (IAPs), heat shock proteins,…) can also highly influence individual steps of caspase activation. Caspases themself can be posttranslationally modified (phosphorylated, ubiquitylated,…) and their activity can be either suppressed or also enhanced. All these processes form complex regulatory network serving...
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Induction and course of programmed cell death in cancer cells after taxane application."
Kábelová, Adéla ; Jelínek, Michael (advisor) ; Gemperle, Jakub (referee)
The taxanes are a class of commonly used anticancer agents, which are very effective in treatment of breast, ovarian, prostate or lung cancer. Taxanes bind to the β-tubulin subunit of microtubules and lead to their stabilization and inhibition of depolymerization. Such microtubules lose their function to form mitotic spindle, thus arresting cells in G2/M phase and resulting in apoptosis. Unfortunately some cells are able to escape from taxanes-induced apoptosis by developing various mechanisms of resistance including alteration in taxanes target microtubules or upregulation of specific transporters that pump the drug out of cells. Other types of resistance are connected with process of programmed cell death (PCD), especially with proteins that after taxane application participate in its successful progress. Taxanes can directly or indirectly modify the activity of Bcl-2-family proteins that control mitochondrial and endoplasmic reticulum integrity, thus regulating the initiation of PCD. Caspases are executioners of PCD and caspase-2 activated by cytoskeletal disruption seems to be especially important in taxanes- induced apoptosis. In some cases can taxane treatment also result in caspase-independent cell death. Special role has protein p53 that seems to be involved only in apoptosis caused by low taxanes...
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The role of autophagy in apoptosis induction by fatty acids in pancreatic beta cells.
Žigová, Ivana ; Němcová, Vlasta (advisor) ; Truksa, Jaroslav (referee)
Type 2 diabetes mellitus represents a metabolic disease reaching epidemic dimensions in the 21st century. Fatty acid-induced apoptosis of pancreatic β-cells significantly contributes to its pathogenesis. Saturated fatty acids (FAs) are strongly cytotoxic for β-cells, whereas unsaturated FAs are well tolerable by β-cells, they are even able to inhibit proapoptotic effects of saturated FAs when co-incubated. According to recent studies, FAs-induced apoptosis in pancreatic β-cells is partly regulated by autophagy, a catabolic process involved in the degradation and recyclation of cell components in lysosomes. The aim of this diploma thesis was to contribute to the clarification of the role of autophagy in FAs-induced apoptosis regulation. We induced apoptosis in human pancreatic β- cell line NES2Y by 1 mM stearic acid (SA) and inhibited it with 0.2 mM oleic acid (OA) co- incubated with SA. We revealed, that the saturated SA used in apoptosis-inducing concentration simultaneously inhibits the autophagic flux in pancreatic NES2Y cell line. When SA is co- incubated with unsaturated OA in concentration sufficient for inhibition of proapoptotic effect of SA, OA is also able to inhibit the block of autophagy induced by the effect of SA. Application of unsaturated OA alone in this concentration did not...
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Cytochrome c and its role in apoptosis
Rajsiglová, Lenka ; Kalous, Martin (advisor) ; Švadlenka, Jan (referee)
Cell energetic metabolism and cell survival are strictly controlled by pathways in which cytochrome molecules play a central role, in particular cytochrome c. It is localized in the mitochondrial intermembrane space with other molecules cooperating in keeping energetic metabolism. Permeabilization of outer mitochondrial membrane by proteins from Bcl-2 family or changes in Ca2+ levels causes cytochrome c release into cytosol. In cytosol cytochrome c interacts with other pro-apoptotic proteins (Apaf-1, procaspase-9) cooperating to form apoptosome and phosphatidylserine. As a result of these interactions, the cell is going to apoptosis. This bachelor thesis summarizes the current state of knowledge of these processes. In the first part it focuses on the biosynthesis of cytochrome c, further on the mechanisms of its releasing from mitochondria and its interactions with other proteins within apoptosis including options of regulation of these processes.
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