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Development of nanochemical tools targeting receptors in the tumor microenvironment
Blažková, Kristýna ; Konvalinka, Jan (advisor) ; Abramson, Jakub (referee) ; Bušek, Petr (referee)
Development of nanochemical tools targeting receptors in the tumor microenvironment Targeting the receptors in the tumor microenvironment is crucial for the future development of targeted therapies, precision medicine and immunotherapy of cancer. The options available now are, however, limited by the availability of specific ligands. The advances in the field strongly rely on the use of antibodies and genetic modifications of immune cells. Availability of small molecules targeting the receptors of interest would allow further development of alternative strategies as well as deepen our understanding of the underlying mechanisms of cancer development, progression and clearance. In the search for new small-molecule ligands and their use for receptor targeting, the prostate-specific membrane antigen (PSMA) and the immune receptors CD3 and CD64 were selected as model targets. The selected method - the phage display of bicyclic peptides - utilizes chemical modification of the displayed three-cysteine peptides to achieve their cyclization and formation of bicycles. The panning of a peptide library displayed on the phages and probed with PSMA revealed a reproducibly-selected amino acid sequence. Interestingly, the phage clone carrying this sequence was a specific binder of PSMA, but the synthesized peptide alone...
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Design, preparation and characterisation of polymer conjugates for protein recognition using peptide ligands
Kryštůfek, Robin ; Konvalinka, Jan (advisor) ; Hořejší, Václav (referee)
Antibodies stand as a cornerstone of many laboratory assays and are used as indispensable tools in biomedicine. iBodies polymer conjugates have been proposed as a possible alternative to antibodies in several traditionally immunological methods. iBodies are based on methacrylamide copolymers decorated with affinity anchors, reporters and targeting ligands which mediate conjugate specificity. The necessity to design ligands and their linkage is a significant obstacle to the generalization of this technology. One way of overcoming this obstacle is the development of secondary antibody mimetics which will use antibodies to obtain specificity for target identification and/or visualization. Based on the literature, several cyclic peptide Fc-binding ligands were designed with linker moieties for attachment to the polymer conjugate. Free and conjugated ligands were compared based on their interaction constants with human IgG. Conjugation with polymer carrier in all cases led to an increase in affinity. Human isotype specificity is dependent on the cyclization method, with single disulfide bridge cyclization exhibiting selectivity for IgG1-4 and IgM, and N→C cyclization leading to abolition of IgM binding. The polymer conjugates have been compared in terms of sensitivity and selectivity using dot blot with...
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Design, preparation and characterisation of polymer conjugates for protein recognition using peptide ligands
Kryštůfek, Robin ; Konvalinka, Jan (advisor) ; Hořejší, Václav (referee)
Antibodies stand as a cornerstone of many laboratory assays and are used as indispensable tools in biomedicine. iBodies polymer conjugates have been proposed as a possible alternative to antibodies in several traditionally immunological methods. iBodies are based on methacrylamide copolymers decorated with affinity anchors, reporters and targeting ligands which mediate conjugate specificity. The necessity to design ligands and their linkage is a significant obstacle to the generalization of this technology. One way of overcoming this obstacle is the development of secondary antibody mimetics which will use antibodies to obtain specificity for target identification and/or visualization. Based on the literature, several cyclic peptide Fc-binding ligands were designed with linker moieties for attachment to the polymer conjugate. Free and conjugated ligands were compared based on their interaction constants with human IgG. Conjugation with polymer carrier in all cases led to an increase in affinity. Human isotype specificity is dependent on the cyclization method, with single disulfide bridge cyclization exhibiting selectivity for IgG1-4 and IgM, and N→C cyclization leading to abolition of IgM binding. The polymer conjugates have been compared in terms of sensitivity and selectivity using dot blot with...
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Evaluation of the properties of polymer conjugates which specifically bind proteins and can be used in molecular biology
Parolek, Jan ; Konvalinka, Jan (advisor) ; Liberda, Jiří (referee)
During last three decades, a great effort was invested to the development of polymer conjugates of low molecular drugs with the aim to improve the specific targeting of drugs to diseased tissues, cells and organs. The main reason for this effort was the fact that high molecular weight copolymers have a favourite distribution profile in tissues and organisms. A linker between a polymer backbone and drug has very important role: it is possible to synthesize a biodegradable linker, which can be enzymatically hydrolyzed. Conversely, there is a possibility to synthesize an inert linker, resistant to the hydrolysis. Proper choice of the suitable precursor- polymer is also essential, hence it has to accomplish all of the stringent demands for biocompatibility. Macromolecular polymer-drug conjugates tend to accumulate in solid tumors because of the so called enhanced permeability and retention (EPR) effect. There is a whole range of possible applications of high molecular polymer-drug conjugates. In the introduction part of this thesis, I summarize potential use of drugs based on poly(N-(2-hydroxypropyl)methacrylamide) (HPMA) copolymers. Moreover, I introduce some therapeutically important proteins used in experimental drug discovery. In our laboratory, we have developed a concept of HPMA copolymers...
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