|
|
Study on impact of selected protein kinase inhibitors on drug resistance mediated by cytochromes P450
Janoušková, Adéla ; Hofman, Jakub (advisor) ; Novotná, Eva (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Adéla Janoušková Supervisor: RNDr. Jakub Hofman, Ph.D. Title of diploma thesis: Study on impact of selected protein kinase inhibitors on drug resistance mediated by cytochromes P450 Pharmacokinetic drug resistance often leads to failure of an anticancer therapy. One of the mechanisms is increased efflux of drugs from tumour cells, whereas some studies suggest that increased drug conversion to an inactive metabolite might be another contributing mechanism. The aim of this work was to define the possible role of CYP3A4 and CYP2C8 enzymes in the phenomenon of pharmacokinetic resistance and to investigate the possibility of its modulation by new targeted drugs. In the first part, we used the MTT proliferation method together with HepG2 cells stably transduced with particular human enzymes and demonstrated significant involvement of CYP3A4 in docetaxel resistance. In the following part, we examined the inhibitory effects of four selected tyrosine kinase inhibitors on the CYP3A4 activity in intact cells using a commercial kit. Cobimetinib and dabrafenib showed significant inhibitory activity, while osimertinib and brivanib did not. In the final part, we demonstrated the ability of the first two...
|
|
|
Study on the role of selected cytochrome P450 isoforms in cytostatic resistance at apoptosis level
Moriová, Magdalena ; Hofman, Jakub (advisor) ; Novotná, Eva (referee)
Charles University Faculty of Pharmacy in Hradci Králové Departement of Pharmacology & Toxicology Student: Magdalena Moriová Supervisor: RNDr. Jakub Hofman, Ph.D. Title of diploma thesis: Study on the role of selected cytochrome P450 isoforms in cytostatic resistance at apoptosis level Cytostatic resistance is one of the most problematic obstacles in oncological treatment. Beside pharmacodynamic mechanisms, pharmacokinetic factors play an important role in drug resistance as well. Enzymatic transformation of active substance to inactive metabolite in tumor cells probably belongs to these mechanisms, however, evidences concerning the relevance of this phenomenon are predominantly either indirect and/or affected by interference elements. Using comparative experiments with HepG2 cell lines with/without CYP3A4 overexpression, we focused on the evaluation of the role of this clinically important enzyme in the resistance against docetaxel. Methodologically, it was the assessment of apoptosis induction (activation of caspases 3/7, 8 and 9) using commercial luminescent kits. Our results suggest significant participation of CYP3A4 enzyme on the reduction of docetaxel anticancer efficacy after 48 h from treatment, whereas this effect was not recorded in earlier intervals. These findings perfectly correlate...
|
|
|
Study on impact of selected protein kinase inhibitors on drug resistance mediated by cytochromes P450
Janoušková, Adéla ; Hofman, Jakub (advisor) ; Novotná, Eva (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Adéla Janoušková Supervisor: RNDr. Jakub Hofman, Ph.D. Title of diploma thesis: Study on impact of selected protein kinase inhibitors on drug resistance mediated by cytochromes P450 Pharmacokinetic drug resistance often leads to failure of an anticancer therapy. One of the mechanisms is increased efflux of drugs from tumour cells, whereas some studies suggest that increased drug conversion to an inactive metabolite might be another contributing mechanism. The aim of this work was to define the possible role of CYP3A4 and CYP2C8 enzymes in the phenomenon of pharmacokinetic resistance and to investigate the possibility of its modulation by new targeted drugs. In the first part, we used the MTT proliferation method together with HepG2 cells stably transduced with particular human enzymes and demonstrated significant involvement of CYP3A4 in docetaxel resistance. In the following part, we examined the inhibitory effects of four selected tyrosine kinase inhibitors on the CYP3A4 activity in intact cells using a commercial kit. Cobimetinib and dabrafenib showed significant inhibitory activity, while osimertinib and brivanib did not. In the final part, we demonstrated the ability of the first two...
|
|
|
Proteomic analysis of soluble and transmembrane proteins in human lymphoma cells
Vít, Ondřej
In the works presented here, we studied molecular changes associated with drug resistance in human mantle cell lymphoma (MCL) cells using proteomics. Our analyses allowed us to identify causal and/or secondary changes in protein expression associated with the development of resistance to the experimental drug TRAIL and the clinically used antimetabolites cytarabine and fludarabine. Resistance of MCL cells to the recombinant proapoptotic cytokine TRAIL was associated with downregulation of key enzymes of purine metabolism. This pathway potentially represents a molecular weakness , which could be used as a therapeutic target for selective elimination of such resistant cells. Resistance to the pyrimidine analog drug cytarabine was associated with cross-resistance to other antinucleosides. Proteomic and transcriptomic analyses showed pronounced downregulation of deoxycytidine kinase (dCK), which activates both purine and pyrimidine antinucleosides. This change explains the cross-resistance and is the causal mechanism of resistance to cytarabine. Our observations suggest that MCL patients, who do not respond to cytarabine-based therapy, should be treated with non-nucleoside drugs. MCL cells resistant to purine-derived antinucleoside fludarabine were cross-resistant to all tested antinucleosides and also...
|
|
|
Proteomic analysis of soluble and transmembrane proteins in human lymphoma cells
Vít, Ondřej ; Petrák, Jiří (advisor) ; Šulc, Miroslav (referee) ; Lenčo, Juraj (referee)
In the works presented here, we studied molecular changes associated with drug resistance in human mantle cell lymphoma (MCL) cells using proteomics. Our analyses allowed us to identify causal and/or secondary changes in protein expression associated with the development of resistance to the experimental drug TRAIL and the clinically used antimetabolites cytarabine and fludarabine. Resistance of MCL cells to the recombinant proapoptotic cytokine TRAIL was associated with downregulation of key enzymes of purine metabolism. This pathway potentially represents a molecular "weakness", which could be used as a therapeutic target for selective elimination of such resistant cells. Resistance to the pyrimidine analog drug cytarabine was associated with cross-resistance to other antinucleosides. Proteomic and transcriptomic analyses showed pronounced downregulation of deoxycytidine kinase (dCK), which activates both purine and pyrimidine antinucleosides. This change explains the cross-resistance and is the causal mechanism of resistance to cytarabine. Our observations suggest that MCL patients, who do not respond to cytarabine-based therapy, should be treated with non-nucleoside drugs. MCL cells resistant to purine-derived antinucleoside fludarabine were cross-resistant to all tested antinucleosides and...
|
|
|
Natural compounds and their effect on 5-fluorouracil in colorectal cancer cell lines
Čumová, Andrea ; Opattová, Alena ; Vodenková, Soňa ; Horák, Josef ; Slíva, D. ; Vodička, Pavel
Colorectal cancer (CRC) is the second most common type of cancer and the second most common cause of cancer related deaths in Europe. 5-Fluorouracil (5-FU) is widely used in treatment of various cancers including CRC, but apart from the cytotoxic effect on cancer cells may also cause adverse toxic side effects. 5-FU is an anti-metabolite with chemical structure similar to that of the pyrimidine molecules of DNA and RNA. However, response to chemotherapy is often limited by drug resistance. The p53 protein is one of the most widely studied tumour suppressors and mutations in TP53 gene are frequently detected in different types of tumours. \nGanoderma Lucidum (GLC) is a mushroom used in Traditional Eastern Medicine which exhibits anti-cancer and anti-proliferative effects in vitro\nThe aim of our study is to define the role of p53 in the interaction between 5-FU and GLC extract and their simultaneous effect on survival in CRC cell lines.\nOur results suggest that GLC extract significantly increases cytotoxicity and genotoxicity of 5-FU in CRC lines with different p53 status and may potentially modulate the response of p53 knock-out cells which are less sensitive to 5-FU treatment. Interaction of conventional chemotherapeutics with natural compounds introduces a novel aspect in cancer research and therapy.\n\n
|
|
|
Proteomics as a tool for understanding molecular mechanisms of human diseases
Pospíšilová, Jana ; Petrák, Jiří (advisor) ; Šulc, Miroslav (referee) ; Kovářová, Hana (referee)
Proteomics is a set of analytical methods which enable qualitative and quantitative characterization of the proteome. Expression proteomics quantitatively compares proteomes of cells, tissues, body fluids or other biological materials to find differencies in protein expression and, based on these differencies, to describe the biological processes occuring in investigated organisms. An initial material for expression proteomic studies are complex mixtures containing thousands of proteins, which are analyzed using separation (electrophoretic and chromatographic) methods, and identified, possibly quantified using mass spectrometry. The aim of this Thesis is to demonstrate the application of the tools of expression proteomics in solving diverse challenges in biomedicine. We employed various proteomic approaches and tools for studying molecular mechanisms of human diseases using pacient biological samples, or a model organism and a cell culture. We were conducting three different research projects, namely: A quest for potencial molecular targets for selective elimination of TRAIL-resistant mantle cell lymphoma cells; Investigation of molecular mechanisms of heart failure using a rat model of the disease induced by volume overload; and Searching for diagnostically usable serum biomarkers of ovarian...
|
|
|
Proteomics as a tool for understanding molecular mechanisms of human diseases
Pospíšilová, Jana
Proteomics is a set of analytical methods which enable qualitative and quantitative characterization of the proteome. Expression proteomics quantitatively compares proteomes of cells, tissues, body fluids or other biological materials to find differencies in protein expression and, based on these differencies, to describe the biological processes occuring in investigated organisms. An initial material for expression proteomic studies are complex mixtures containing thousands of proteins, which are analyzed using separation (electrophoretic and chromatographic) methods, and identified, possibly quantified using mass spectrometry. The aim of this Thesis is to demonstrate the application of the tools of expression proteomics in solving diverse challenges in biomedicine. We employed various proteomic approaches and tools for studying molecular mechanisms of human diseases using pacient biological samples, or a model organism and a cell culture. We were conducting three different research projects, namely: A quest for potencial molecular targets for selective elimination of TRAIL-resistant mantle cell lymphoma cells; Investigation of molecular mechanisms of heart failure using a rat model of the disease induced by volume overload; and Searching for diagnostically usable serum biomarkers of ovarian...
|
|
|
Microtubule-active drugs: mechanism of action and resistance
Dostál, Vojtěch ; Libusová, Lenka (advisor) ; Rösel, Daniel (referee)
Microtubular cytoskeleton represents a target for a myriad of diverse chemical compounds, referred to as microtubule-active drugs. Produced by certain plants, animals or microbes, the substances often effectively elicit cell death - especially in animals and also in plants to a certain extent, but never in species which produce them to defend against their predators. Nowadays, several microtubule-active substances constitute hallmarks of anti-cancer treatment and agricultural weed control. There is an enormous sum of knowledge about the action of paclitaxel (taxol), vinca alkaloids and colchicine, three best-known microtubule active compounds used in medicine, and new research often challenges the previously accepted theories. This work investigates the mechanism of action of microtubule-active drugs from the angle of biochemistry and cell biology, as well as from the physiological standpoint. Effects on microtubule levels and dynamics and the path towards the cell death are reviewed. In the last chapter, attention is given to drug activity in both animal and plant bodies and, finally, to drug-producing plant species which often show substantial resistance.
|
|
|
Study of the cleavage kinetics of Gag polyprotein from HIV-1 virus by the viral proteinase
Krištofičová, Ivica ; Ingr, Marek (advisor) ; Martínek, Václav (referee)
Gag polyprotein is the precursor of HIV-1 structural proteins, required for correct assembly, budding and maturation of viral particle within HIV-1 life cycle. The process of maturation into an infectious virion is dependent on Gag and GagPol cleavage at nine predefined sites by HIV-1 proteinase. Its disruption is one of the main targets of HIV treatment. HIV-1, however, develops resistance to the proteinase inhibitors by creating mutations in both the proteinase and the substrate. The Gag processing by HIV-1 proteinase is a highly sequential process, that happens in specific order and rate. Previous biochemical studies determined the kinetic data of these processes using oligopeptides representing naturally occuring cleavage sites. This thesis describes the cleavage of the Gag polyprotein itself, which is the natural substrate of HIV-1 proteinase. For this purpose, the full-length Gag polyprotein was recombinantly prepared in bacterial expression system. The cleavage was carried out and its products were analyzed via SDS-PAGE and Western blotting. The substrate specificity of the wild-type and mutant HIV-1 proteinase with respect to the full-length wild-type Gag polyprotein was compared. Substantial differences were observed between the rates of individual steps of cleavage by the wild-type and mutant...
|
guest ::
