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Effect of mitochondrially targeted senolytic agents on the development of respiratory diseases
Rennerová, Michaela ; Štemberková-Hubáčková, Soňa (advisor) ; Neckář, Jan (referee)
Aging is a complex biological process characterized by gradual decline in the physiological functions of cells and tissues, leading to the activation of a process known as cellular senescence. This results in the development of structural and functional changes in the organism accompanied by an increased risk of various diseases. Respiratory diseases are among the most common chronic conditions associated with the accumulation of senescent cells in the body. Current treatment for chronic respiratory diseases primarily focuses on symptom relief rather than addressing the primary cause of these conditions. Given that senescent cells play a significant role in the pathogenesis of respiratory diseases, the future of therapies lies in their elimination using senolytic agents. Despite promising results from some studies, current research is limited by the heterogeneity of senescent cells, which is reflected in their sensitivity to senolytic agents and the variability of therapeutic responses. Mitochondria play a central role in the development and maintenance of the senescent cell phenotype by regulating key processes such as energy metabolism and cellular signaling, regardless of the type of senescent cell. Thus, targeting mitochondria in senescent cells may represent a promising therapeutic strategy...
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STAT3 signalling pathway modulation and its impacts on cell phenotype, senescence and secretome.
Novotný, Ondřej ; Reiniš, Milan (advisor) ; Šmahel, Michal (referee)
Cellular senescence represents an effective barrier to tumour growth on the one hand, on the other hand, senescent cells secrete substances that create a protumourigenic environment. Understanding and influencing these processes will bring new approaches in the fight against tumours and other serious diseases. The IL-6/JAK2/STAT3 signalling pathway is crucial both in oncogenesis and in the induction of cellular senescence and it also has a major influence on the composition of the secretome of senescent cells. Targeted blockade of this pathway could therefore change the tumour microenvironment, either by directly affecting the induction of senescence itself, or by adjusting secretion and thereby by attenuation of the immunosuppressive environment induced by produced cytokines. The aim of this thesis is to find out whether and how inhibitors of the STAT3 signalling pathway can change the secretome of senescent and proliferating tumour cells. Based on the comparison of the toxicity and effectiveness of the STAT3 signalling pathway inhibition by Stattic analogues on proliferating TC-1 tumour cells, I selected two suitable inhibitor molecules for further experiments. I found out that these selected inhibitors significantly reduce the secretion of important pro-tumour signalling molecules by TC-1 tumour...
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Late effects of oncolocigal treatment for childhood cancers
Zichová, Andrea ; Eckschlager, Tomáš (advisor) ; Kolenová, Alexandra (referee) ; Tesařová, Petra (referee)
Late effects of oncological treatment for childhood cancers Abstract The study aimed to describe the occurence of subsequent neoplasms and their risk factors at the Departement of Pediatric Haematology and Oncology, Motol University Hospital, Prague. Moreover, we focused on sporadic renal angiomyolipomas as the most frequent benign subsequent neoplasms. Out of 4,059 survivors treated between 1975 - 2018 for a solid tumor on Departement of Pediatric Haematology and Oncology, 170 (4.2 % of all survivors) had at least one subsequent malingant neoplasm, 21 of them (0.5 of all survivors) developed more subsequent malignant neoplasms, and 34 (0.8 of all survivors) developed one subsequent malignant neoplasm and at least one subsequent benign neoplasm. Mortality among patients with subsequent malignant neoplasm was 38 %, i.e. 1.6 % of all survivors. The most common subsequent malignant neoplasms was thyroid carcinoma (37; 19.2 %), central nervous system tumors (25; 13 %), and soft tissue sarcomas (23; 11.9 %). 119 (2.9 %) survivors developed only subsequent benign neoplasm. Out of 1,098 survivors who underwent ultrasound examination between 2014 - 2019, 48 (4.4 %) had sporadic renal angiomyolipoma; moreover, 20 of them also had another subsequent neoplasm. The median age at diagnosis was 27.9 years, and the median...
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Cell response to genotoxic stress-based anti-cancer therapies
Imrichová, Terezie ; Hodný, Zdeněk (advisor) ; Rossmeislová, Lenka (referee) ; Rotrekl, Vladimír (referee)
The dissertation deals with a cell response to genotoxic stress, specifically to anti-cancer treatments with a genotoxic mechanism of action. In principle, cells can respond to these perturbing stimuli in several ways: in case of severe DNA damage, they usually undergo apoptosis or enter senescence. In case of minor DNA damage, or upon defective checkpoint mechanisms, they may continue the cell cycle, either with successfully repaired DNA or with mutations of various kind. Thanks to selection pressure, the mutations that provide cells with a certain growth advantage under conditions of continuing genotoxic stress, gradually accumulate and render the tumor treatment-resistant. In my thesis, I focus on several aspects of this whole process. First, I participated in a characterization of a radioresistant and anoikis-resistant population of prostate cancer cells. This population was generated by irradiating cells 35 times by 2 Gy, a regime used in clinics. After this treatment, a population of low-adherent cells emerged that demonstrated increased expression of EMT- and stem cell markers. The low-adherent state of these cells was maintained by Snail signaling and their anoikis resistance by ERK1/2 signaling. Interestingly, after a protracted period of time, these cells were able to re-adhere and...
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Cellular senescence escape mechanisms - anti-cancer barrier
Davidová, Eliška ; Hodný, Zdeněk (advisor) ; Horníková, Daniela (referee)
Cancer is one of the most dangerous diseases of the modern world. Therefore, many world laboratories engaged in research into the causes leading to the outbreak of this insidious disease. In this context, it has already been found that the normal animal cells do not divide indefinitely, but have a finite replicative life span. After this period, cells undergo either apoptotic processes or enter into so-called senescence, typical for proliferation arrest, but preserved metabolic processes. Further research has revealed that senescence serves as an effective anticancer program and currently is shed light on its significance in relation to various physiological or pathological processes associated with aging. In this work, the focus is on the role of senescence as a barrier for cancer development, and effectiveness. It can be assumed, that if the senescent cycle arrest functioned perfectly, the incidence of cancer among people would be recorded in much lower extent. The aim of this thesis is the current knowledge about the physiological and pathological roles of senescence and possible causes of overcoming this barrier, the result may be the uncontrolled cell division and tumorigenicity.
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Changes in oxidative phosphorylation during development of cellular senescence
Zima, Michal ; Hodný, Zdeněk (advisor) ; Kašparová, Dita (referee)
Cellular senescence represents a state of permanent cell cycle arrest. It is considered to be an active response of the cell to various extrinsic and intrinsic types of stress, which are damaged and/or uncapped telomeres, activation of certain oncogenes, DNA damage and effects of several cytokines. This thesis describes current mechanisms which may result in establishment of senescence phenotype, putting those facts in association with changes in oxidative phosphorylation. In thesis are also mentioned features of senescence cells and their impact on the neighborhood. Special attention is focused on the role of reactive oxygen species in promotion of cellular senescence, mechanisms of their elevation, the role of NADPH oxidases and the inhibition of mitochondrial oxidative phosphorylation complexes by activity of cytokine signaling pathways STAT3 and TGFbeta. Key words: cellular senescence, reactive oxygen species, cytokines, mitochondria, oxidative phosphorylation chain, NADPH oxidases, Signal Transducer and Activator of Transcription 3 (STAT3), TGF-β, DNA damage response (DDR)
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Mechanisms of phenotypic plasticity induced by genotoxic stress
Přibyl, Miroslav ; Hodný, Zdeněk (advisor) ; Remešová, Hana (referee) ; Vomastek, Tomáš (referee)
Therapy resistance of malignant cells represents the main reason responsible for the failure of cancer therapy. The growth of malignant cells at primary tumour sites but most importantly the dissemination of tumour cells and their growth at secondary sites, are the main reasons why patients eventually succumb to the disease. Even novel immune-based therapies find their limitation in most tumour types. The therapy resistance is mediated by the tumour cells but also by other cellular components of the tumour microenvironment. Understanding the tumour cells mechanisms and the tumour microenvironment features responsible for therapy resistance enables the development of novel therapeutic strategies. Here, we show that ionizing irradiation, 5-azacytidine, and IFNγ treatments induced expression of suprabasin (SBSN) and therapy-resistant low-adherent phenotype in cancer cells. Knockdown of SBSN resulted in suppression of the phenotype. Next, we identified aberrantly elevated SBSN in the bone marrow of a subgroup of myelodysplastic syndromes (MDS) patients. SBSN was expressed by myeloid-derived suppressor cells (MDSCs) and showed significant anti-correlation with T cell abundance and CCL2 levels, hence promises a prognostic value in clinical use. We compiled the most of the relevant knowledge of SBSN...
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DNA damage and signalling pathways in cellular senescence
Hubáčková, Soňa
Organisms such as mammals need tissue renewal as an important process for maintenance of their viability. Because proliferation is essential also for tumourigenesis, cells need tumour-suppressor mechanisms to protect organism against cancer. Cellular senescence, the permanent state of cell-cycle arrest, features one of these intrinsic barriers against tumourigenesis after DNA damage and understanding of this process may lead to finding of novel therapeutic targets and to optimization of chemotherapy for patients with cancer. In the first part of the PhD thesis, we investigated activation of JAK/STAT signalling pathway in drug-induced senescence. We used genotoxic drugs like aphidicolin, camptothecine, 5-bromo- 2'-doexyuridin, etoposide or thymidine to induce premature senescence in normal and cancer cells. All this chemicals were able to persistently activate JAK/STAT signalling in monitored cells. Activation of STATs was accompanied with up-regulation of expression of interferon-stimulated genes (ISGs), such as MX1, IRF1, IRF7 and PML. Since IRF1 and IRF7 can be directly involved in stimulation of the IFN genes, we show activated expression as well as secretion of IFNbeta and IFNgamma, but not IFNalpha in drug-induced senescent cells. Furthermore, an inhibition of JAK1 as a major kinase of STAT...
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Mechanisms of phenotypic plasticity induced by genotoxic stress
Přibyl, Miroslav ; Hodný, Zdeněk (advisor) ; Remešová, Hana (referee) ; Vomastek, Tomáš (referee)
Therapy resistance of malignant cells represents the main reason responsible for the failure of cancer therapy. The growth of malignant cells at primary tumour sites but most importantly the dissemination of tumour cells and their growth at secondary sites, are the main reasons why patients eventually succumb to the disease. Even novel immune-based therapies find their limitation in most tumour types. The therapy resistance is mediated by the tumour cells but also by other cellular components of the tumour microenvironment. Understanding the tumour cells mechanisms and the tumour microenvironment features responsible for therapy resistance enables the development of novel therapeutic strategies. Here, we show that ionizing irradiation, 5-azacytidine, and IFNγ treatments induced expression of suprabasin (SBSN) and therapy-resistant low-adherent phenotype in cancer cells. Knockdown of SBSN resulted in suppression of the phenotype. Next, we identified aberrantly elevated SBSN in the bone marrow of a subgroup of myelodysplastic syndromes (MDS) patients. SBSN was expressed by myeloid-derived suppressor cells (MDSCs) and showed significant anti-correlation with T cell abundance and CCL2 levels, hence promises a prognostic value in clinical use. We compiled the most of the relevant knowledge of SBSN...
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Genotoxic stress and senescence in tumour cells: impact on the tumour growth and anti-tumour immunity.
Sapega, Olena ; Reiniš, Milan (advisor) ; Brábek, Jan (referee) ; Šmahel, Michal (referee)
Premature cellular senescence is the process of permanent cell cycle arrest in response to various inducers, such as DNA damage, oxidative stress, chemotherapy agents, and irradiation. Senescent cells produce and secrete numbers of cytokines, chemokines, growth factors, which compose specific senescence-associated secretory phenotype (SASP). Senescence is considered to be an important barrier against tumor progression. On the other hand, senescent cells can also exert protumorigenic effects in their microenvironment. Based on this concept, the major aim of this thesis was to determine tumor cells senescence in terms of different inducers, namely chemotherapeutic agent docetaxel (DTX) and cytokines IFNγ and TNFα, and to demonstrate the role of immunotherapy in senescent cells elimination. Our results show that DTX-induced senescent cells can exert a tumor-promoting effect when co-injected with proliferating cells in mice. Importantly, we demonstrate that IL-12-based immunotherapy suppresses senescence-accelerated tumor growth. These results suggest that IL-12-based immunotherapy can be effectively used in anti-tumor therapy mainly in a case when the microenvironment is altered by the presence of tumor senescent cells. On the other hand, the data we obtained in vitro show that bystander or...
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