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Molecular mechanisms of sensitivity and resistance towards chemotherapeutics in most frequent solid cancers
Čumová, Andrea ; Vodička, Pavel (advisor) ; Černá, Marie (referee) ; Hlaváč, Viktor (referee)
Despite the great effort, the main obstacle to cancer therapy represents low response towards common chemotherapeutics and/or resistance. Chemoresistance causes cancer relapse and formation of metastases, dramatically challenging the prognosis of patients. It is estimated, that about 90% of cancer mortality can be directly or indirectly attributed to chemoresistance. There are several intrinsic or acquired cellular mechanisms of tumor chemoresistance, with DNA repair being one of the key culprits affecting the response towards chemotherapeutics in cancer cells. This is based on the fundamental principle of their action, as the majority of chemotherapeutics are designed to increase DNA damage and to suppress DNA repair or DNA damage response, ultimately triggering the death of malignant cells. Consequently, understanding the complex mechanisms of DNA repair and its regulation is essential for more targeted and effective treatment of cancer patients. In this dissertation Thesis, we attempted to elucidate some of the regulatory mechanisms of DNA repair and their effects on response to common chemotherapeutics. We confirmed that single nucleotide polymorphisms in microRNA binding sites of DNA repair genes may influence the patient's survival and response to cancer therapy. We investigated the role of...
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The effects of chemicals on cell lines viability
Zemanová, Anita ; Obruča, Stanislav (referee) ; Brázda, Václav (advisor)
The subject of this diploma thesis is the influence of selected chemicals on cell lines viability. The theoretical part contains options of cancer treatment by using chemotherapeutics including their mechanism of action and side effects. Additionally, there are described alternative DNA structures with focus on G-quadruplexes and ligands that interact with G-quadruplexes. These compounds are promising drugs in cancer treatment due to their high specificity to G-quadruplexes, which are found in telomeres of chromosomes. G-quadruplex interacting ligands by stabilization of G-quadruplexes can inhibit the enzyme telomerase, which is necessary for telomere lengthening of rapidly dividing cancer cells. Additionally, the possibilities of viability assays are summarized in the theoretical part. The aim of the experimental part was comparing cytotoxic activity between commercially available chemotherapeutics and selected G-quadruplex interacting ligands. Another task was the study of apoptosis and necrosis after the treatment of selected chemicals on cell lines and after the localization of ligands interacting with G-quadruplexes in the cells of the breast cancer cell line. In the experimental part, G-quadruplex interacting ligands have been shown to exhibit similar cytotoxic activity to commercially available chemotherapeutic agents.
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Detection of Pt derivatives using ICP mass spectrometry
Zelinová, Karin ; Hložková, Michaela (referee) ; Vašinová Galiová, Michaela (advisor)
This Bachelor´s thesis deals with the monitoring of chemotherapeutic penetration into tumor cells. Due to the toxicity of drugs, targeting them is absolutely essential from the point of view of minimizing the interference with healthy tissue of the patient. In order to achieve the best possible targeting, it is necessary to monitor the penetration of chemotherapeutics into cells. The subject of study was platinum-based drugs therefore the ICP-MS method was chosen to analyse the drug content in cells, because it is suitable for fast and reliable detection of trace amounts of elements. The theoretical part of the Bachelor´s thesis focuses on the description of ICP-MS, as a method, which was chosen for the detection of platinum derivates. It also summarizes the use of platinum-based drugs in cancer therapy. The practical part of the thesis deals with the analysis of cells exposed to platinum-based chemotherapeutics. Detection and quantification of platinum in the cells were determined by both SN-ICP-MS and LA-ICP-MS. To verify the results, the analysis of the solution was also performed by the AAS method. The results show, that the drug was most readily taken up by A2780 cells. It was also shown that cisplatin was the most accumulated drug.
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Analysis of chemotherapeutics in extracellular vesicles
Kožnarová, Simona ; Hložková, Michaela (referee) ; Vašinová Galiová, Michaela (advisor)
Extracellular vesicles are a newly discovered way of cell-to-cell communication. The issue is still significantly unexplored, especially in the case of cancer. The goal of this pilot study was to attempt to detect platinum contained in extracellular vesicles by ICP-MS. In this study, samples of ovarian cancer cell lines treated with platinum derivatives, a type of chemotherapeutic drug, were used. This method was proved as able to detect platinum, even as able to determine its concentration reliably. The quantity of platinum in vesicles was around 1–2 % of the total platinum added to the system. The results varied according to the used platinum derivative, the cell line and the number of cells releasing the vesicles. Most platinum was determined in vesicles of the SK-OV-3 line, which is naturally resistant to this treatment, for all platinum derivatives. From these results it can be concluded that the use of ICP-MS is also advisable for additional research on this issue.
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Antibiotická rezistence patogenních bakterií u vybraných druhů zájmových zvířat
Kaliská, Tereza
Some strains of pathogenic bacteria are capable of resistance to antibacterial agents. This resistance makes it difficult to treat diseases in both human and veterinary medicine. The most well-known pathogens of domestic animals, mainly dogs and cats, are mentioned in the context of the bachelor thesis. The thesis highlights the importance of understanding the mechanisms of resistance. It describes mobile elements, the principle of efflux pumps and spontaneous chromosomal mutations. Prevention should be the basis for preventing resistance from spreading further in the population. The observance of good hygiene habits, the appropriate use of antibiotics in the correct dosage and legislative adjustments on agricultural farms should be implemented on a global scale. The development of antimicrobial substances, including chemotherapeutics, should continue. At the same time, more empha-sis should be placed on the search for new alternatives. Mainly plant phytobiotics look promising.
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Study of Genotoxicity of Organic Compounds Using DNA Biosensors
Augustín, Michal ; Vyskočil, Vlastimil (advisor) ; Trnková, Libuše (referee) ; Labuda, Ján (referee)
Proposed dissertation thesis presents novel hybrid electrochemical DNA biosensors based on distinct forms of pyrolytic graphite ("edge-plane" and "basal-plane") and their potential in terms of applicability in the field of DNA electrochemistry. Testing of the applicability of the presented bioanalytical tools was preceded by thorough optimization process involving selection of the optimal values for the most crucial operational parameters of the electrochemical DNA biosensors fabricated by means of electrostatic adsorption - deposition potential (Edep), deposition time (tdep), optimal DNA concentration for electrostatic adsorption (cg(DNA)), and possible involvement of convection during the adsorption procedure. Initially, applicability of presented bioanalytical tools was investigated in relation to monitoring DNA damage by utilization of triplet of external DNA damaging sources - UV light irradiation, one- electron oxidants, and hydroxy radicals. Outcome of the damaging processes was monitored directly (via monitoring changes in the redox signals of DNA) or indirectly (via monitoring changes in the redox signals of redox indicator) by the use of voltammetric methods - square- wave voltammetry (SWV), cyclic voltammetry (CV), linear-sweep voltammetry (LSV), and electrochemical impedance...
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Detection of Pt derivatives using ICP mass spectrometry
Zelinová, Karin ; Hložková, Michaela (referee) ; Vašinová Galiová, Michaela (advisor)
This Bachelor´s thesis deals with the monitoring of chemotherapeutic penetration into tumor cells. Due to the toxicity of drugs, targeting them is absolutely essential from the point of view of minimizing the interference with healthy tissue of the patient. In order to achieve the best possible targeting, it is necessary to monitor the penetration of chemotherapeutics into cells. The subject of study was platinum-based drugs therefore the ICP-MS method was chosen to analyse the drug content in cells, because it is suitable for fast and reliable detection of trace amounts of elements. The theoretical part of the Bachelor´s thesis focuses on the description of ICP-MS, as a method, which was chosen for the detection of platinum derivates. It also summarizes the use of platinum-based drugs in cancer therapy. The practical part of the thesis deals with the analysis of cells exposed to platinum-based chemotherapeutics. Detection and quantification of platinum in the cells were determined by both SN-ICP-MS and LA-ICP-MS. To verify the results, the analysis of the solution was also performed by the AAS method. The results show, that the drug was most readily taken up by A2780 cells. It was also shown that cisplatin was the most accumulated drug.
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Analysis of chemotherapeutics in extracellular vesicles
Kožnarová, Simona ; Hložková, Michaela (referee) ; Vašinová Galiová, Michaela (advisor)
Extracellular vesicles are a newly discovered way of cell-to-cell communication. The issue is still significantly unexplored, especially in the case of cancer. The goal of this pilot study was to attempt to detect platinum contained in extracellular vesicles by ICP-MS. In this study, samples of ovarian cancer cell lines treated with platinum derivatives, a type of chemotherapeutic drug, were used. This method was proved as able to detect platinum, even as able to determine its concentration reliably. The quantity of platinum in vesicles was around 1–2 % of the total platinum added to the system. The results varied according to the used platinum derivative, the cell line and the number of cells releasing the vesicles. Most platinum was determined in vesicles of the SK-OV-3 line, which is naturally resistant to this treatment, for all platinum derivatives. From these results it can be concluded that the use of ICP-MS is also advisable for additional research on this issue.
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Immunogenic cell death
Šímová, Michaela ; Drbal, Karel (advisor) ; Javorková, Eliška (referee)
According to the danger model, the immune system is activated by endogenous molecules known as danger-associated molecular patterns (DAMP) that are externalized from the interior of a dying cell to the cell surface or released into the extracellular space. Due to the loss of plasma membrane integrity a necrotic cell death as well as several types of proinflammatory programmed cell death are considered to be immunogenic, whereas apoptosis, on contrary, has been initially defined as a tolerogenic type of cell death. However, under certain circumstances, the immune response can be initiated by an apoptotic cell after exnternalization of DAMP molecules by newly described secretory pathways. This phenomenon was observed on tumor cells as a result of some widely used therapeutic modalities and is known as immunogenic cell death (ICD). Nomenclature of selected types of cell death is part of this thesis. The aim of this bachelor thesis is to provide an evidence of the experimental support for ICD theory during in vivo initiation of the immune response. I will evaluate the correlation between ICD and the induced exposure of DAMP molecules on the surface of tumor cells or their secretion to the extracellular space.
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Iron homeostasis in malaria
Wernerová, Klára ; Šuťák, Róbert (advisor) ; Voleman, Luboš (referee)
Although malaria is a well-studied infectious disease, we are still unable to fight it effectively, as evidenced by a large number of infected people. Many drugs are available against malaria. However, because of incessantly emerging resistances, new, more effective antimalarials need to be developed. One possibility is to target the parasite's iron metabolism, the essential element of all organisms. Iron participates in DNA synthesis, respiration, energy production. It acts as a cofactor of ribonucleotide reductase, and metalloproteins with FeS clusters or heme. During the infection, the parasite must compete with the host for nutrients, including iron. The mechanism of iron uptake or excretion in malaria parasite is not completely clear. Only two iron transporters are known, but it is already evident, that there must be more of them. The Plasmodium parasite digests a large amount of hemoglobin, which is degraded into free heme and denatured globin. Free heme is toxic to the cell though. Plasmodium defends itself from the toxicity of free heme by forming chemically inert hemozoin. This unique mechanism of protection against the free heme toxicity is very useful for Plasmodium and other blood parasites, but it also becomes an advantageous target for drugs because the mechanism is present only in...
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