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Effects of natural compounds on viability of tumor cell lines
Boleslavská, Barbora ; Poljaková, Jitka (advisor) ; Bořek Dohalská, Lucie (referee)
Cancer is considered to be one of the most serious issues of medicine nowadays. Moreover, its incidence is still rising. Despite the huge progress in modern treatment methods, cancer therapy is still limited by many difficulties. This work focuses on the natural substances such as epigallocatechin gallate, caffeine, Cannabis sativa ethanol extract, Origanum acutidens water extract, Mentha piperita water extract and its effects on the human neuroblastoma cell line UKF-NB-4. The first part of the bachelor thesis deals with determining the viability of human neuroblastoma cell line UKF-NB-4 exposed to tested substances as well as it studies the effects of those substances on the cell cycle and caspase activity. Finally, it was tested, whether those substances are able to induce apoptosis in neuroblastoma cell lines. Tests were undertaken on the MUSETM cell analyzer and on the flow cytometer. The second part of the bachelor thesis focuses on the expression of protein p53 and retinoblastoma protein in neuroblastoma cell lines exposed to tested substances. Detection was carried out by Western blot analysis. Epigallocatechin gallate exhibited the most significant effect on human neuroblastoma cell line. It lowers the expression of retinoblastoma protein as well as it arrests cells between G0/G1 and S...
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The comparison of properties of cell lines resistant to ellipticine, doxorubicin, and cisplatin
Černá, Tereza ; Poljaková, Jitka (advisor) ; Eckschlager, Tomáš (referee)
7 Abstract Neuroblastoma is the most common extracranial solid tumor of childhood. Despite advances in cancer diagnosis and therapy, the treatment of some forms of neuroblastoma is still complicated. One of the major complications of the chemotherapy is a developed drug resistance. This master thesis deals with the effect of cytostatics on protein and gene expression of selected proteins, which may contribute to chemoresistance of the human neuroblastoma cell line UKF-NB-4. The sensitive line UKF-NB-4 and the resistant line UKF-NB-4CDDP , UKF-NB-4DOXO and UKF-NB-4ELLI were exposed to cisplatin, doxorubicin, ellipticine for 24, 48 and 72 hours. The Western blot analysis showed that cytostatic agents cisplatin, doxorubicin or ellipticine added to the sensitive neuroblastoma cell line UKF-NB-4 in amounts which are added to resistant neuroblastoma cell lines in order to maintain resistance induced expression of p53 and reduced expression of retinoblastoma protein pRb after 72 hours of cultivation. Differences in the expression of RAS protein, cytochrome P450 1A1, 3A4 and cytochrome b5 has not been shown. Changes in the expression of the studied proteins in resistant lines UKF-NB-4CDDP , UKF-NB-4DOXO and UKF-NB-4ELLI cultured with and without cytostatic agents were not detected by the Western blot analysis....
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Effects of valproic acid and its combinations with cytostatic agents on tumor cells in vitro
Hinďoš Hřebačková, Jana ; Dyr, Jan (advisor) ; Vávrová, Jiřina (referee) ; Entlicher, Gustav (referee)
Cancer is one of the most challenging problems the modern medicine is facing today. An increasing incidence and a great variability of tumor cells are the main reasons those drive the research to develop better diagnostics and therapeutic protocols. Histone deacetylase inhibitors, a group of epigenetic chemotherapeutics, are able to improve the performance of currently used anticancer agents. Vaplroic acid that is commonly used as antiepileptic drug exhibits a remarkable anticancer activity by itself as well as it is capable of therapy potentiation based on other therapeutic agents. Its effect to inhibit growth of tumor cells and induce apoptotic cell death seems to be even greater under hypoxic conditions (<1% O2). This study is focused on effect of valproic acid on neuroblastoma cell lines in vitro under normoxic and hypoxic conditions. We observed significantly greater efficacy of valproic acid in hypoxia compared to normoxia. The mechanism of induction of apoptotic cell death is based on disruption of the balance between pro- and antiapoptoic proteins. Intrinsic apoptotic pathway is probably initiated by the action of 19 kDa variant of proapoptotic protein Bax on mitochondrial membrane. Moreover, we examined the efficiency of a combined treatment of neuroblastoma cells with valproic acid and...
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Mechanisms of anticancer drug action in neuroblastomas
Groh, Tomáš ; Stiborová, Marie (advisor) ; Levová, Kateřina (referee) ; Vališ, Karel (referee)
Cancer cells are able to adapt to different stress factors such as hypoxia, which is caused by insufficient tumor vascularization. An increased acetylation status of histones H3 and H4 in UKF-NB-3 and UKF-NB-4 neuroblastoma cell lines was found to be a mechanism of adaptation of these cells to hypoxia. An increase in acetylation of histones H3 and H4 is suggested to cause changes in the structure of chromatin that lead to activation of gene transcription. In addition, cultivation of tested neuroblastoma cells under hypoxic conditions changes expression of proteins of a transcription factor N-myc, which is essential for development of neuroblastomas. This transcription factor is also responsible for a metabolic adaptation of neuroblastoma cells, increases their aggressiveness and its expression leads to a worse prognosis of the disease. Inhibitors of histone deacetylases (HDAC) are suggested to be the promising agents exhibiting various anticancer effects. They can induce cell cycle arrest, differentiation or programmed cell death in sensitive tumors. In this study, the effect of one of inhibitors of HDACs, valproate, on expression of proteins of transcription factors N-myc and hypoxia inducible factor 1α (HIF-1α) was investigated. Valproate decreases protein levels of both transcription factors in...
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Epigenetic modification of DNA of tumor cell lines in normoxia and hypoxia
Omaňa Gudiňo, Žaneta ; Poljaková, Jitka (advisor) ; Hinďoš Hřebačková, Jana (referee)
5 Abstract Neuroblastoma is one of the most common cancer diseases diagnosed in children. This rapidly growing solid tumor is usually formed by hypoxic areas which arise as a consequence of inefficient and disorganized neovascularization. The cells stressed by hypoxia triggers transcription of many genes necessary for their survival, and conversely stop the production of proteins which are not necessarily needed for the survival in these severe conditions. The adaptation of cells to hypoxic conditions may appear due to the epigenetic regulation of metabolism associated with chromatin remodeling which involves the DNA methylation and also the posttranslational modifications of histones. Among the most important of these, there is the acetylation of lysine residues of histones associated with the DNA strands loosening, facilitated binding of transcription factors and the activation of gene expression. Thus, the first part of this study is concerned with changes in the acetylation of histones H3 and H4 of human neuroblastoma cell lines UKF-NB-3, UKF-NB-4, SH-SY5Y and SK-N-AS, cultured in parallel under standard culture conditions and in the absence of oxygen (hypoxia, 1% O2) for 24 hours, which are studied by Western blot analysis. Thereupon, the activity of histone deacetylases and histonacetyltransferases,...
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Genetic changes in neuroectodermal tumors detected by molecular biological methods.
Vosecká, Tatiana ; Vícha, Aleš (advisor) ; Eckschlager, Tomáš (referee)
9 ABSTRACT Tatiana Labudová: Genetic changes in neuroectodermal tumours detected by molecular biological methods. Charles University in Prague, Faculty of Science, Department of Anthropology and Human Genetics Thesis, 75 pages,8 supplements, 2012 This thesis is concerned to neuroectodermal tumours that make a major group of infant tumour diseases. Genetic material gained from patients with neuroectodermal tumours was examined using comparative genomic hybridization (CGH) and interphasic fluorescence in situ hybridization (I-FISH). The aim of this Thesis is to prove chromosomal changes and to create the whole genetic profile. According to these profiles can be determined tumourgenetic cascade or specific genetic changes that lead to malignant tumours. In some cases (f.e. neuroblastoms) the genetic profile helps us to determine a subtype of disease and it's biological behaviour. Keywords: tumour diseases, neuroblastoma, CNS tumours, pheochromocytoma, Ewing's sarcoma, neuroectodermal tumour, comparative genomic hybridization, interphase fluorescence in situ hybridization
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Study of gene expression profile of ellipticine - resistant neuroblastoma cell line UKF-NB-4
Pinkas, Michael ; Poljaková, Jitka (advisor) ; Hinďoš Hřebačková, Jana (referee)
Neuroblastoma (NB) is a malignant embryonal tumor of the peripheral sympathetic nervous system derived from neural crest and is the most common tumor in infants. If the protooncogen MYCN is amplified in the case of high risk neuroblastoma, the current therapy fails. The biggest issue is the development of resistance. Ellipticine (ELLI) is a potential antineoplastic drug, whose cytotoxic effect is mainly based on the inhibition of topoisomerase II, its intercalation into the double helix structure of DNA and formation of adducts with DNA after enzymatic activation by cytochromes P450, peroxidases, sulfotransferases and N,O-acetyltransferases. Long-term cultivation of NB cell line UKF-NB-4 with ELLI leads to resistance, which is multifactorial. (i) It appears that ELLI is not effluxed from cells of the line UKF-NB-4ELLI as in the case of doxorubicin resistance in UKF-NB-4, but is transported from the nucleus and sequestrated in intracellular compartments. Cytotoxicity of ELLI is reduced also by (ii) low intracellular pH and (iii) decreased expression of topoisomerase II. (iv) Expression of enzymes activating ELLI is unchanged on the mRNA level detected by DNA microarray. However, enhanced expression of enzymes activating ELLI (cytochrome P450 3A4 and cyclooxygenase-1) is detected by qRT-PCR. Moreover...
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Differences in histone acetylation in normoxia and hypoxia
Čepek, Pavel ; Poljaková, Jitka (advisor) ; Eckschlager, Tomáš (referee)
Histones and their N and C terminal tails undergo different covalent modifications that regulate gene transcription. Among these histone modifications are methylation, ubiquitinilation, SUMOylation, ADP- ribosylation, phosphorylation, proline izomerization, deimination and acetylation. Histone acetylation is regulated by histonacetyltransferases (HATs) and histondeacetylases (HDACs). The balance between acetylation/deacetylation influences chromatin condensation and thus regulates gene transcription. Acetylation balance is disrupted in many human cancers and this fact can contribute to the development of malignant diseases. Histondeacetylase inhibitors (HDACi) can restore this acetylation imbalance. One of these HDACi is valproic acid (VPA) which has been used in treatment of epilepsy for decades. VPA shows antitumour effect in many studies. Decreased expression of n-myc oncoprotein, inhibition of tumour growth and angiogenesis are one of these anticancer effects observed in neuroblastoma cell lines after treatment with VPA. Despite the fact that exact mechanism of antitumour effect of VPA remains unclear, one of the most important mechanisms is hyperacetylation of histone H3 and H4. It is shown in this work that VPA increases acetylation of histones H3 and H4 in human neuroblastoma cell lines...
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The effect of histone deacetylase inhibitor vaplroate on activity and expression of cytochromes P450 and peroxidases oxidizing ellipticine
Göttlicherová, Markéta ; Souček, Pavel (referee) ; Stiborová, Marie (advisor)
Ellipticine is a potent antineoplastic agent, whose mode of action is considered to be based mainly on DNA intercalation and inhibition of topoisomerase II. Ellipticine was also found to form covalent DNA adducts mediated by its enzymatic activation with cytochromes P450 (CYP) and peroxidases. The next study demonstrated increasing formation of these ellipticine-DNA adducts by histone deacetylase inhibitor valproate (VPA) in neuroblastoma cells. This phenomenon correlates with increasing cytotoxicity of ellipticine induced by this histone deacetylase inhibitor. This observation can be explained by several mechanisms. One of them can be loosening the structure of chromatine, which leads to accessing DNA for modification. Another one is the effect of VPA on activities and expression of enzymes metabolizing ellipticine. This study was aimed to test the second hypothesis. Since VPA has been shown to be metabolized by similar enzymes as ellipticine is, we have studied the effect of VPA (i) on oxidation of ellipticine by cytochromes P450 and peroxidases, (ii) on activities of the CYP enzymes, which significantly participate in oxidation of ellipticine (CYP1A, CYP3A) and (iii) on expression of enzymes oxidizing ellipticine (CYP1A1, CYP3A4, lactoperoxidase). Oxidation of ellipticine in vitro by model...
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