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Role of genetic factors in the prognosis and prediction of efficacy of chemotherapy in breast carcinoma patients
Brynychová, Veronika ; Souček, Pavel (advisor) ; Macůrek, Libor (referee) ; Stružinská, Ivana (referee)
Changes in the regulation of apoptosis and cell cycle are involved in tumor development, progression, and resistance to antitumor therapy. The aim of this work was to evaluate the importance of apoptotic caspases and regulators of cytokineses as possible prognostic and predictive markers in breast carcinoma patients. In addition to determining the transcript levels of selected genes in tumor and control tissues obtained from breast carcinoma patients, we have also focused on the importance of alternative splice variants of caspases and their potential genetially determined regulation. We analysed the obtained data in relation to the clinical-pathological characteristics of the tumors, the progression-free survival of patients and to the response of the patients to the neoadjuvant chemotherapeutic treatment. Part of the work was determination of protein expression levels and verification of the importance of selected candidates for the effect of chemotherapy by functional study. The transcript levels of caspase 2, 3, 7, 8, 9, 10, the specifically detected splice variants caspase 2S, 2L, 3A and B, 3S, 9A, 9B, 8L, and the transcript levels of KIF14 and CIT in breast carcinomas were unrelated to the progression-free survival of patients, or to the response of patients to neoadjuvant treatment. The...
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IL 57 - Sporadic colorectal cancer: From genetic make-up to complex phenotypic measurement, from risk determination to prognostic markers
Vodička, Pavel ; Slyšková, Jana ; Pardini, B. ; Naccarati, A. ; Souček, P. ; Vodičková, Ludmila ; Vymetálková, Veronika ; Svoboda, Miroslav ; Foersti, A. ; Hemminki, K.
Colorectal carcinogenesis (CRC), is a complex process, resulting in both genomic and chromosomal instabilities. The valid theories of carcinogenesis accent either the role of somatic mutation or the surrounding microenvironment, however neither of them explains all features of cancer. Uncontrolled proliferation and genomic instability point to the DNA damage response and repair as to the key players. In the present study, we will overview several biomarkers in mapping heterogeneous complex CRC disease and providing prognostic information.\nVariants in genes involved in important pathways, such as DNA repair, cell cycle control, folate metabolism and methylation, insulin resistance and obesity, ABC transporters, selenoprotein genes, genes involved in inflammatory/immune response have shown various degree of association with CRC risk. We present also the data on mutations in high risk genes involved in colorectal carcinogenesis. Gene expression levels were determined in relevant pathways and complemented with other important parameters (epigenetic regulators of transcription by methylation). Additionally, the role of post-transcriptional regulation via miRNA or lncRNA was investigated in relation to the risk of CRC and the efficacy of chemotherapy. We have discovered several genetic and epigenetic markers affecting independently the prognosis of CRC. Functional DNA repair tests (complex phenotype) have been implemented as markers of individual susceptibility to sporadic CRC and its prognosis.\nAn application of the whole set of various biomarkers is inevitable to define the phenotypic landscape of the disease and to delineate the individual response to the therapy.\n
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The study of signaling pathways that modulate multidrug resistance
Dvořák, Pavel ; Souček, Pavel (advisor) ; Daum, Ondřej (referee) ; Benson, Veronika (referee)
The study of signaling pathways that modulate multidrug resistance The theme of cancer cell resistance to anti-cancer drugs including the common mechanisms of resistance development and the theory of cancer stem cells was introduced in the Introduction to the doctoral thesis. The theoretical part was focused more deeply on the two topics - the role of ATP-binding cassette (ABC) transport proteins and chromosomal abnormalities in the development of cancer chemoresistance. The possible therapeutic potential for the treatment of cancer was stressed for both topics. The Results were composed of the commentaries on the five published works, which the author of the thesis conducted as the main author. The first work brought the evidence supporting the hypothesis of the existence of ABC gene expression profiles (signatures), which are common to multiple types of tumors and are associated with significant clinical consequences. These general ABC gene expression profiles could possibly form a new hallmark of cancer. The second work studied more closely a group of acute myeloid leukemia patients, who did not achieve complete cytogenetic remission after two attempts to maintain remission of the malignant disease. The new entity, consisting of patients with the translocation t(2;11)(p21;q23) without the...
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Potenciální využití WIP1 fosfatasy v terapii nádorového onemocnění prsu
Pecháčková, Soňa ; Macůrek, Libor (advisor) ; Souček, Pavel (referee) ; Krejčí, Lumír (referee)
Cells in our body respond to genotoxic stress by activation of a conserved DNA damage response pathway (DDR). Depending on the level DNA damage, DDR signaling promotes temporary cell cycle arrest (checkpoint), permanent growth arrest (senescence) or programmed cell death (apoptosis). Checkpoints prevent progression through the cell cycle and facilitate repair of damaged DNA. DDR represents an intrinsic barrier preventing genome instability to protect cells against cancer development. WIP1 (encoded by PPM1D) phosphatase is a major negative regulator of DDR pathway and is essential for checkpoint recovery. This thesis contributed to the understanding of molecular mechanisms of WIP1 function and revealed how WIP1 can be involved in tumorigenesis. Firstly, we described that WIP1 protein levels decline during mitosis by APC-Cdc20 dependent proteasomal degradation. WIP1 is phosphorylated at multiple residues which inhibit its enzymatic activity. We propose that inhibition of WIP1 in mitosis allows sensing of low levels of DNA damage that appear during unperturbed mitosis. Further, we identified novel gain-of-function mutations of PPM1D which result in expression of C-terminally truncated WIP1. These truncated WIP1 variants are enzymatically active and exhibit increased protein stability. As result, cells...
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Site-directed mutagenesis of human cytochromes P450 family 1 and their interacting partners
Milichovský, Jan ; Martínek, Václav (advisor) ; Befekadu, Asfaw (referee) ; Souček, Pavel (referee)
Cytochromes P450 represent a large group of proteins metabolizing variety of substrates. Many of them are responsible for metabolism of xenobiotics including drugs and chemical carcinogens. Heme-protein cytochrome b5 is a single-electron donor cooperating with a NADPH:cytochrome P450 reductase and NADH:cytochrome b5 reductase 3 enzyme. Cytochrome b5 can affect the xenobiotic metabolism via modulation of the cytochromes P450 activity. One of the goals of the Ph.D. thesis was to utilize site directed mutagenesis of cytochromes P450 family 1 to elucidate the mechanism of their nitroreductase activity. Another aim was to study the interaction between cytochrome b5 and cytochromes P450 of the 1A subfamily using site directed mutagenesis on presumed protein-protein contact interface. Another goal was to utilize the combination of theoretical and experimental approaches to explain variance in the reduction state of several human cytochromes P450 heterologously expressed in intact bacterial cells. The results found in the thesis show that nitroreductase activity of CYP1A1, CYP1A2 and CYP1B1 is mediated by the presence of a particular hydroxyl group in their active centre. Single mutation introducing a hydroxyl group to the specific part of CYP1B1 active site to the active site turned on its artificial...
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