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Host-microbe interactions and its consequences for intestinal inflammation and carcinogenesis
Kejzlarová, Leona ; Kverka, Miloslav (advisor) ; Smrž, Daniel (referee)
A number of physiological and pathological processes, including the transition from chronic inflammation to cancer, are affected by commensal microbes. However, abundance of microbes and ability to produce active metabolites in the intestine depend on environmental factors, particularly diet. Microbes can influence this process in two ways, by producing genotoxic substances that directly damage the epithelium or by stimulating the inflammatory response. The aim of my thesis was to study the interaction among gut microbiota, diet and the immune system with the subsequent influence on the development of colorectal cancer (CRC) in an experimental mouse model. Animals were fed synthetic diets containing either normal amounts of animal protein (17%; KD) or elevated amounts of animal protein (51%; HPD) throughout the experiments. Two weeks after the diets were introduced, intestinal tumors were induced by administering azoxymethane (AOM) and inducing acute inflammation with 2% sodium dextran sulfate one week after AOM injection. At the end of the experiment I evaluated the number of tumors in the colon and the status of the immune response in the intestine, mesenteric lymph nodes and spleen. To study the effect of macrophages, a similar experiment was performed in animals with depleted macrophages using...
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The study of tumour DNA virus integrations
Frčková, Tereza ; Saláková, Martina (advisor) ; Šroller, Vojtěch (referee)
Most people perceive viruses primarily as a cause of diseases such as cold, flu or COVID-19. But there are also viruses with oncogenic potential. There are several ways in which viruses contribute to the development of tumors. In the case of human papillomavirus and Merkel cell virus, it is the expression of oncogenes encoded in viral genomes. The virus may be integrated into the host genome, which can also promote the development of carcinogenesis. In this work, the method of detection of integrated papillomavirus sequence by polymerase chain reaction (DIPS PCR) was used to detect the integration breakpoints in human papillomavirus (HPV) in positive cell lines originated from cervical cancer, clinical head and neck cancer samples associated with HPV, and clinical samples of Merkel cell carcinoma. In the case of Merkel cell carcinoma, DIPS PCR method was performed on samples isolated from fresh frozen tissues and from formalin fixed paraffin embedded (FFPE) sections of tumor samples. In the case of tonsillar tumors associated with HPV, only fresh frozen tissues were used. Integration breakpoints were detected in samples from both fresh frozen and FFPE tissues using DIPS PCR method. For the detection of HPV genome integration breakpoints, a new set of primers was tested and optimized on the SiHa...
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Terapeutické monoklonální protilátky v nádorovém léčbě
Danišová, Terezie
In recent years, therapy with monoclonal antibodies has been increasingly used in clinical practice. Treatment based on these antibodies has a wide range of advantages over classical therapeutic procedures such as chemotherapy, including reduced side effects. Their greatest advantage is their specificity towards cancer cells, which does not damage surrounding healthy cells. The aim of this compilation work is to summarize and present the molecular basis of tu-mour development and the processes that monoclonal antibodies suppress, stimulate, and contribute to stopping tumour progression. This compilation work provides a basic literary over-view of carcinogenesis at the molecular level, which is necessary for understanding the princi-ples on which monoclonal antibodies function. This work later focuses on monoclonal antibodies, their mechanism of action, and production techniques.
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Knockout isoforem metalothioneinu pomocí metody CRISPR-Cas9 u adherentních tkáňových kultur
Duda, Jakub
It is not too long ago, that genome modifications were very complex, or, in some cases, almost impossible to achieve, but with the discovery and description of the CRISPR system in prokaryotes, a lot of breakthroughs came to the human knowledge, and thanks to some of these breakthroughs the CRISPR system has been modified to be used as a genome editing tool in eukaryotic organisms. Genetic modifications could in theory be the key to cancer therapy in modern pharmacy, and this thesis focuses on Metalmetallothionein (MT) proteins, which are commonly found in organisms and are beneficial to the organism (as inhibotors of oxidative stress, or as antioxidants binding heavy metals, for example), but can also be dangerous. Because, according to the isoform, and also the type of tissue, MTs can cause the development of cancer tissue and tumour growth, sometimes because of their presence, in other cases because of their absence. This thesis was focusing on the possible knock-out of all isoforms of MT at once, using CRISPR/Cas9 method, and thereby infucencing one of the very important factors in carcinogenesis. The result of this thesis is the achievement of knock-out of the MT3 isoform.
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The study of tumour DNA virus intergrations
Frčková, Tereza ; Saláková, Martina (advisor) ; Šroller, Vojtěch (referee)
Most people perceive viruses primarily as the cause of diseases such as cold, flu or COVID-19. But there are also viruses with oncogenic potencial. There are several ways in which viruses provide to the development of tumors. In the case of human papillomavirus and Merkel cell virus, this is the expression of oncogens encoded in viral genomes. The virus may be integrated into the host genome, which can also promote to the development of carcinogenesis. In this work, the method of detection of integrated papillomavirus sequence by polymerase chain reaction (DIPS PCR) was used to detect the integration breakpoints in human papillomavirus (HPV) of positive cell lines originated from cervix cancer, clinical head and neck cancer samples associated with HPV, and clinical samples of cancer from Merkel cells. In the case of Merkel cell carcinoma, the DIPS PCR method was performed on samples isolated from freshly frozen tissue and from cuts of tumor samples stored in paraffin. In the case of tonsil tumors associated with HPV, it was only freshly frozen tissue. Using the DIPS PCR method, integration breakpoints were detected in samples from both freshly frozen tissue and tissue stored in paraffin. For the detection of HPV genome integration breakpoints, a new set of primers was tested, which was optimized on...
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The importance of cell-free HPV DNA detection
Milt, Petr ; Saláková, Martina (advisor) ; Horníková, Lenka (referee)
Human papillomaviruses (HPV) are small, nonenveloped DNA viruses that are abundant in the population. They are sexually transmitted or spread by close contact with mucosa and skin. Papillomaviruses can cause lesions and warts on the skin and mucosa. In addition, high-risk HPV types, especially HPV 16 and 18, are associated with squamous cell carcinomas such as cervical cancer, oropharyngeal cancer and carcinomas of the vulva, anus, penis and vagina. Early detection and the right evaluation of the risk of recurrence are crucial for effective treatment. Cell-free DNA released from cells into body fluids has potential in cancer diagnosis. Cell-free circulating HPV DNA, in the blood of patients with HPV-associated cancers is a promising and highly sensitive biomarker, useful for monitoring treatment efficiency, early detection of the disease and estimation of recurrence risk. Key words: HPV, carcinogenesis, cfDNA, cfHPV DNA, significance of detection, cervical cancer, oropharyngeal cancer
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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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The role of APOBEC proteins in HPV-induced carcinogenesis
Frolíková, Daniela ; Šmahelová, Jana (advisor) ; Šroller, Vojtěch (referee)
Apolipoprotein B mRNA editing enzyme, catalytic polypeptide (APOBEC) are a family of evolutionarily conserved cytidine deaminases with the ability to bind and modify RNA and/or ssDNA. APOBEC1-4 have a number of functions in cells. Members of the APOBEC3 subfamily cause restriction of foreign nucleic acids, retrotransposons and viruses, including human papillomaviruses (HPV), and may contribute to the clearance of infection. Certain HPVs are referred to as oncogenic viruses because of their ability to induce immortalization and transformation of epithelial cells via E5, E6 and E7 oncoproteins. E6 and E7 can also induce transcription or inhibit degradation of some APOBEC3. This results in an increase in their levels in cells. APOBEC3 also act as cellular mutators, as they can catalyze deaminations on transiently produced ssDNA during replication or transcription. Deregulation of APOBEC3 caused by oncoproteins may contribute to mutagenesis. This bachelor thesis focuses on APOBEC proteins, their activation and function during HPV-induced carcinogenesis, and in particular the extent and consequences of APOBEC3 mutations. Keywords: APOBEC, mutagenesis, papillomavirus, oncoproteins, carcinogenesis
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Role of benzo[a]pyrene in cancer development
Vaňátková, Petra ; Moserová, Michaela (advisor) ; Kubíčková, Božena (referee)
4 ABSTRACT Cancer is nowadays one of the most serious diseases. Tumor development is a multistage process in which the effect of internal and external factors lead to failure of regulatory and defense mechanisms of the organism and to the accumulation of mutations which are generated by these organisms. Chemical carcinogens and also biological and physical factors can be regarded as the main external factors. Polycyclic aromatic hydrocarbons are large group of chemical carcinogens. One of them, benzo[a]pyren is the most studied polycyclic aromatic hydrocarbon. Carcinogenic, mutagenic and teratogenic effects of benzo[a]pyrene had been shown on laboratory animals. Benzo[a]pyrene is considered as the main carcinogen in tobacco smoke and is connected with lung cancer development among smokers. Benzo[a]pyrene is metabolized in activation or detoxication pathways by enzymes of mixed function monooxygenase systeme of cytochromes P450. The most important enzymes involved in the activation of these compounds are CYP1A1 and CYP1B1 with cooperation of epoxide hydrolase. The reactive species generated in its activation pathway are able to form covalent adducts with DNA. The most important carcinogenic product of benzo[a]pyrene is benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide, which can caused irreversible ganges in...
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