|
|
Impact of new FLT3 inhibitors on daunorubicin accumulation in ABCB1-expressing leukemic cells
Králová, Adéla ; Čečková, Martina (advisor) ; Jirkovský, Eduard (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Adéla Králová Supervisor: doc. PharmDr. Martina Čečková, Ph.D. Consultant: Mgr. Simona Suchá Title of Diploma thesis: Impact of new FLT3 inhibitors on daunorubicin accumulation in ABCB1-expressing leukemic cells Fms-like tyrosine kinase 3 (FLT3) inhibitors represent a new generation of drugs in the treatment of acute myeloid leukemia (AML). Standard therapeutic regimen of AML is initiated with induction therapy consisting of cytarabine and anthracyclines. The disadvantage of this combination is emerging resistance often caused by the ABCB1-mediated efflux. Therefore, simultaneous inhibition of FLT3 and ABCB1, which is inhibited by FLT3 inhibitors used in clinical practice, appears to be a beneficial approach to therapy. However, their effectiveness is declining hence the effort to develop new FLT3-inhibiting molecules. The aim of our work was to evaluate whether our two promising new FLT3-inhibiting compounds would inhibit ABCB1 as well. Promyelocyte cells overexpressing ABCB1 (HL60-ABCB1) and parent HL60-par were used in this study alongside AML-derived cell lines (MOLM-13, THP-1, Kasumi-1). Employing accumulation studies on HL60-ABCB1, strong inhibitory effect towards ABCB1 was demonstrated...
|
|
|
Molecular events associated with resistance to tyrosine kinase inhibitors in leukemia cells.
Hrdinová, Tereza
Chronic myeloid leukemia (CML) is a myeloproliferative stem cell disease characterized by the expression of BCR-ABL oncoprotein with constitutive tyrosine kinase activity. Although the development of tyrosine kinase inhibitors (TKI) such as imatinib dramatically improved the treatment of CML, a certain subset of patients develops resistance to TKI drugs. The most common cause of TKI resistance are point mutations in the BCR-ABL1 gene, followed by other mutation-independent mechanisms. Survival and proliferation of CML cells in the presence of TKI drugs are accompanied by adaptive changes in their metabolism. Drug resistance can be maintained by extrinsic signals, among which exosomes, small vesicles released by (drug-resistant) cells, have been shown to play an important role. The aim of this thesis was to characterize two CML cell lines sensitive and resistant to imatinib, as well as the exosomes derived from imatinib-resistant CML cells by proteomic approaches. Identification of metabolic vulnerabilities in drug-resistant cells enables their targeting by clinically available drugs, thus offering potential therapeutic targets for their selective elimination. Analysis of exosomes derived from imatinib-resistant cells can identify specific membrane surface proteins exploitable as clinically relevant...
|
|
|
Heat-shock proteins and plant tolerance against high temperature stress
Ott, Kristián ; Hála, Michal (advisor) ; Konrádová, Hana (referee)
In context with ongoing climate change, the average temperature is still rising. This is a problem mainly for agriculture and production of groceries, because plants generally have difficulties when coping with ambient temperature higher than 40 řC. If there would be continuing trend in decrease of global food production, it could cause problems with feeding still growing world population. Organisms in general developed many mechanisms of stress adaptation. One of these evolutionary adaptions to high temperature stress is production of heat shock proteins (HSPs). HSPs are very conserved family of proteins present in both prokaryotes and eukaryotes. This thesis summarizes present knowledge about the HSPs and their function (not only) during the high temperature stress in plants, but some of the information presented in this thesis were obtained also from other organisms. The thesis starts with general introduction to the high temperature stress and how plants can sense the ambient temperature. Next is general mechanism of induction of HSPs and their classification, structure, and mechanism of action. The possibility of future use of HSPs in agriculture and medicine is opened in last chapter.
|
|
|
Impact of new FLT3 inhibitors on daunorubicin accumulation in ABCB1-expressing leukemic cells
Králová, Adéla ; Čečková, Martina (advisor) ; Jirkovský, Eduard (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Adéla Králová Supervisor: doc. PharmDr. Martina Čečková, Ph.D. Consultant: Mgr. Simona Suchá Title of Diploma thesis: Impact of new FLT3 inhibitors on daunorubicin accumulation in ABCB1-expressing leukemic cells Fms-like tyrosine kinase 3 (FLT3) inhibitors represent a new generation of drugs in the treatment of acute myeloid leukemia (AML). Standard therapeutic regimen of AML is initiated with induction therapy consisting of cytarabine and anthracyclines. The disadvantage of this combination is emerging resistance often caused by the ABCB1-mediated efflux. Therefore, simultaneous inhibition of FLT3 and ABCB1, which is inhibited by FLT3 inhibitors used in clinical practice, appears to be a beneficial approach to therapy. However, their effectiveness is declining hence the effort to develop new FLT3-inhibiting molecules. The aim of our work was to evaluate whether our two promising new FLT3-inhibiting compounds would inhibit ABCB1 as well. Promyelocyte cells overexpressing ABCB1 (HL60-ABCB1) and parent HL60-par were used in this study alongside AML-derived cell lines (MOLM-13, THP-1, Kasumi-1). Employing accumulation studies on HL60-ABCB1, strong inhibitory effect towards ABCB1 was demonstrated...
|
|
|
The role of exosomes in chronic myeloid leukemia
Březinová, Lenka ; Krijt, Matyáš (advisor) ; Holada, Karel (referee)
Exosomes are extracellular vesicles of a size range 30-150 nm whose function has been explored in chronic myeloid leukemia (CML) due to their role in proliferation of CML cells, remodelling the bone marrow niche, angiogenesis and resistance to treatment with tyrosin- kinase inhibitors (TKIs). Although BCR-ABL kinase is effectively targeted by TKIs, 20-30 % of patients remain resistant to treatment. Resistance of CML cells to TKIs treatment is supported by exosomes. Exosomes transport proteins, nucleic acids, chemokines and small molecules that stimulate anti-apoptotic or suppress pro-apoptotic processes in leukemic cells. Anti-apoptotic processes are especially enhanced by upregulated protein levels: TGF- β1, USP6 and FGF2 and various types of RNA: miR-365, miR-21, Hsa_circ_0058493 and mRNA for BCR-ABL. In contrast leukemic cells tend to reduce the number of pro-apoptotic molecules, including miR-320, miR-328 and miR-146a-5p. Leukemic cells modify the bone marrow microenvironment through exosomes in the way to support their survival and also in order to adjust expression of adhesion and pro- angiogenic molecules. An important role in those processes play miR-126, miR-210 and miR- 92a. Neither the number of processes affected by CML exosomes nor their potential use in the treatment of CML is...
|
|
|
Molecular events associated with resistance to tyrosine kinase inhibitors in leukemia cells.
Hrdinová, Tereza ; Vyoral, Daniel (advisor) ; Klener, Pavel (referee) ; Holoubek, Aleš (referee)
Chronic myeloid leukemia (CML) is a myeloproliferative stem cell disease characterized by the expression of BCR-ABL oncoprotein with constitutive tyrosine kinase activity. Although the development of tyrosine kinase inhibitors (TKI) such as imatinib dramatically improved the treatment of CML, a certain subset of patients develops resistance to TKI drugs. The most common cause of TKI resistance are point mutations in the BCR-ABL1 gene, followed by other mutation-independent mechanisms. Survival and proliferation of CML cells in the presence of TKI drugs are accompanied by adaptive changes in their metabolism. Drug resistance can be maintained by extrinsic signals, among which exosomes, small vesicles released by (drug-resistant) cells, have been shown to play an important role. The aim of this thesis was to characterize two CML cell lines sensitive and resistant to imatinib, as well as the exosomes derived from imatinib-resistant CML cells by proteomic approaches. Identification of metabolic vulnerabilities in drug-resistant cells enables their targeting by clinically available drugs, thus offering potential therapeutic targets for their selective elimination. Analysis of exosomes derived from imatinib-resistant cells can identify specific membrane surface proteins exploitable as clinically relevant...
|
|
|
Determination of antibiotics in the soil ecosystem
Brož, Tomáš ; Zlámalová Gargošová, Helena (referee) ; Mravcová, Ludmila (advisor)
This work deals with a current issue of increasing drug concentrations and thus the growing number of resistant bacteria in the soil. One of the problem helping this issue is the fertilization of agricultural fields with animal faeces, in which antibiotics occur in an unchanged and still active form, as well as the insufficient effectiveness of conventional methods used in wastewater treatment plants. In an effort to improve the monitoring of this problem, a method for the determination of these antibacterial agents in the soil matrix, using solid phase extraction, and also a UPLC/MS method for their evaluation have been developed and optimized. From the group of sulfonamide antibiotics, sulfacetamide, sulfadiazole, sulfamerazine, sulfamethazine, sulfamethoxazole, sulfapyridine, sulfasalazine, sulfathiaosal and trimethoprim were selected. The lowest limit of detection for the method is 0.3 µg/g for sulfathiazole and the highest of 8.1 µg/g for sulfasalazine. The highest average yields were achieved with sulfamethoxazole, namely 63 ±8 %.
|
|
|
Induction and course of programmed cell death in cancer cells after taxane application."
Kábelová, Adéla ; Jelínek, Michael (advisor) ; Gemperle, Jakub (referee)
The taxanes are a class of commonly used anticancer agents, which are very effective in treatment of breast, ovarian, prostate or lung cancer. Taxanes bind to the β-tubulin subunit of microtubules and lead to their stabilization and inhibition of depolymerization. Such microtubules lose their function to form mitotic spindle, thus arresting cells in G2/M phase and resulting in apoptosis. Unfortunately some cells are able to escape from taxanes-induced apoptosis by developing various mechanisms of resistance including alteration in taxanes target microtubules or upregulation of specific transporters that pump the drug out of cells. Other types of resistance are connected with process of programmed cell death (PCD), especially with proteins that after taxane application participate in its successful progress. Taxanes can directly or indirectly modify the activity of Bcl-2-family proteins that control mitochondrial and endoplasmic reticulum integrity, thus regulating the initiation of PCD. Caspases are executioners of PCD and caspase-2 activated by cytoskeletal disruption seems to be especially important in taxanes- induced apoptosis. In some cases can taxane treatment also result in caspase-independent cell death. Special role has protein p53 that seems to be involved only in apoptosis caused by low taxanes...
|
|
|
Testing of the sensitivity of bacteria on selected substances in school environment
Švehlová, Vendula ; Pavlasová, Lenka (advisor) ; Skýbová, Jana (referee)
The aim of this bachelor thesis lies in describing and executing of methods which are determining the resistance of various types of bacteria to antibiotics and selected common household disinfectants and also selected products for oral hygiene. Due to the structure of these methods they can be used f.e. in practical classes in grammar or high schools. Antibiotic discs and other supplies are used when examining resistence of bacteria towards antibiotics which are affordable for aforementioned schools. We can see the efficiency of various antibiotics and disinfectants and we can easily decide which ones are worth of purchase and which ones are not very functional alltogether. Last items tested are samples of mouthwashes and toothpastes. The mechanisms behind the efficiency of all these substances and the sensitivity of bacteries will be described either in practical and theoretical part of this thesis. Key words: Antimicrobials substances, resistance, inhibition, agar soil, bacteria
|
|
|
Transformation of potato with protease inhibitor gene SPI-2
Říhová, Barbora ; Fischer, Lukáš (advisor) ; Vítámvás, Pavel (referee)
The subject of my thesis was to genetically modify a potato for increased resistance against its pathogens and pests. In developing a resistant plant, it is quite common to use the same type of molecules that plants use themselves in their defense reactions. In this work I used the gene SPI-2 originating from a honeycomb moth (Galleria mellonella). The protein SPI-2 is a member of serine protease inhibitors. Since the previous attempts of the team to detect the protein in transformed plants haven't been successful, the basic form of the gene was modified by adding a Kozak sequence near the start codon, which should have increased the translation initiation and hence increase the level of the protein. Two constructs were prepared for the transformation: SPI-2-T a SPI-2-Y. They differ by one amino acid, which slightly changes their inhibitory activity. First, the construct SPI-2-T was used for a transient transformation of tobacco Nicotiana benthamiana by agroinfiltration of its leaves. Then both constructs were used for a stable transformation of Solanum tuberosum cv. Desireé. The detection of the protein has not been successful, although the inserted gene was transcribed and his sequence was verified by sequencing. It is therefore most likely that the protein has a low stability in the cytoplasm....
|
guest ::
