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Renal carcinoma bological therapy and the role of cell signaling checkpoints
Černá, Kristýna ; Otavová, Katarína (advisor) ; Tolde, Ondřej (referee)
Principles of targeted biological treatment of metastatic renal cell carcinoma include mainly inhibitors of the tyrosine kinase receptors VEGFR and inhibitors of intracellular mTOR kinase. Across the new healing regimes there are the blockades of immune checkpoints of the immune system cell. Detailed molecular characterization of tumor is necessary not for only aplication of medicaments, but also for the development of drugs that target specific molecular pathway of cell signalization of the carcinoma cells. The work is focused on the description of the signaling pathway mTOR and VEGF in metastatic renal cell carcinoma. It summarizes all validated clinical biomarkers which are used to diagnose and stratify patients for the treatment of mRCC. It also offers insight into the present experiments that are finding new specific molecular markers. That may be the future solution for customized approach in the treatment of renal carcinoma an tumors in general.
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Mechanism of anti-cancer activity induced by sesquiterpene lactones.
Filandr, František ; Novák, Petr (advisor) ; Grobárová, Valéria (referee)
One way to stop tumor growth in organism is to induce differentiation, apoptosis or necrosis of tumor cells. A class of chemicals known to induce apoptosis and inhibit proliferation in leukemia cells are sesquiterpene lactones. One of these lactones is cnicin, a bitter tonic used in liqueurs, found in the plant Cnicus benedictus. The mechanism of this inhibition, is not fully understood but certain signaling pathways are suspected, mainly the recently discovered Hippo signaling pathway which controls the organ size and apoptosis in mammalian cells. The core kinase of this signaling pathway is MST1/2 protein and its activation by sesquiterpene lactone cnicin resulting in cleavage of its active N-terminal domain is observed in this work. Also, the effect of cnicin on down-regulating main oncoprotein deregulated in leukemia cells C-MYC is studied. In addition the results of q-PCR also show significant down-regulation of anti-apoptotic BCL2 and MCL1 genes and cMYC oncogene. (In Czech)
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Adenosine metabolism and its role in cell physiology
Neumannová, Kateřina ; Novotný, Jiří (advisor) ; Hansíková, Jana (referee)
Adenosine is not just a major component of important molecules such as ATP, RNA or cAMP, but also has its own signaling function. Therefore, its extracellular level is strictly maintained by balance in its formation, degradation and transport. Both inside and outside the cell adenosine is formed mainly through degradation of ATP and is eliminated by two enzymes, adenosine kinase and adenosine deaminase. Transport of adenosine through the cell membrane is provided by nucleoside transporters, which are either equilibrative or concentrative according to the mechanism of transfer. All three processes described above contribute to maintaining adenosine level under normal conditions and its increase in pathological situations. Extracellular adenosine as a signal molecule binds to adenosine receptors (subtypes A1, A2A, A2B, A3) that affect many cellular signaling pathways via G-proteins. By these pathways adenosine regulates energy homeostasis, controls the function of various organs and also modulates the nervous and immune system and thus it may participate in a number of pathological processes. Pharmacological affecting of specific adenosine receptors or enzymes involved in its metabolism can serve as an effective therapy. Some drugs based on this system are already in use, others are being tested, and many...
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Role of oxidative stress in cardioprotection induced by exercise.
Kyclerová, Eva ; Nováková, Olga (advisor) ; Kašparová, Dita (referee)
Cardiovascular diseases are the major cause of death in developed countries. It is known that heart muscle can activates endogenous protective pathways in response to stress, thereby increasing resistance against ischemia/reperfusion (I/R) injury. Protective pathways involve many signaling molecules and reactive oxygen species (ROS) play an important role among them. ROS are applied in cardioprotection induced by various stimuli, such as chronic hypoxia, preconditioning and also physical exercise. It has been demonstrated that regular physical exercise naturally leads to the positive adaptation to protect heart against injury. The balance between production of ROS and their removal by antioxidant protection system is important for the right functioning of the heart. The overproduction of ROS occurs in pathological conditions such as an I/R leading to oxidative stress contributing to subsequent damage of heart. ROS may contribute not only to the injury but in the mild concentrations, resulting for example from physical exercise, ROS are important signaling molecules involved in series of events leading to cardioprotection. Slightly increased oxidative stress protects the heart by increasing the capacity of antioxidant system, stimulates angiogenesis, activates mitochondrial biogenesis and physiological...
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The role of Src-family kinases in the immunological synapse of antigen presenting cells.
Kotlabová, Klára ; Brdička, Tomáš (advisor) ; Brábek, Jan (referee)
Antigen presentation during which antigen fragments in complex with MHC glycoproteins are recognized by T cell antigen-specific receptors is necessary for the initiation of adaptive immune response. During this process, immunological synapse is assembled at the site of contact between the T cell and the antigen-presenting cell (APC). This leads to the activation of receptors on the surface of both cells followed by triggering of multiple signaling pathways. However, our knowledge about the signaling occurring at the APC-side of the IS is limited in comparison to the T cell side. Here, we analyze role of Src family kinases in the APC signaling pathways. For this purpose, constructs targeting Csk kinase to the plasma membrane of APCs were prepared to inhibit SFKs there. We show that expression of these constructs inhibits activation of SFKs, calcium mobilization and cell activation of K46 B cell line. Further, expression of these constructs in hematopoietic progenitors attenuates their differentiation into dendritic cells which then results in their decreased ability to stimulate T cells.
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Mechanizmy regulace signální transdukce povrchovými proteiny leukocytu*.
Štěpánek, Ondřej ; Brdička, Tomáš (advisor) ; Brábek, Jan (referee) ; Vomastek, Tomáš (referee)
The core of the doctoral thesis "Regulation of signal transduction by leukocyte surface proteins" consists of three publications in international peer-reviewed journals dealing with leukocyte signaling both at the level of individual signaling pathways and in the context of a multicellular organism. Most attention is paid to signaling via the T cell receptor (TCR), which plays a central role in the development and function of T cells and represents a key signaling pathway for proper function of the adaptive component of the immune system. Transmembrane protein tyrosine phosphatase CD148 was considered a negative regulator of TCR signaling through dephosphorylation of LAT and PLCγ1 proteins. This study brings evidence that CD148 is able to modulate signaling also at the level of Lck, both positively and negatively. The net effect of CD148 activity on the TCR signaling is determined by the intracellular biochemical context, notably, the presence of another tyrosine phosphatase CD45. The second project dealt with the characterization of a transmembrane adaptor protein PRR7. This adapter inhibits TCR signaling via down-regulation of the intracellular Lck and cell surface TCR levels. The research concerning the signaling in the environment of a multicellular organism is represented by the analysis of...
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Mechanisms of MHCII signaling in B lymphocytes
Kotlabová, Klára ; Brdička, Tomáš (advisor) ; Černý, Jan (referee)
During the initiation of an antigen-specific immune response, peptide fragments originating from the antigen are presented in complex with MHC class II glycoproteins (MHCgpII) on the surface of the antigen presenting cells (APC). Antigen recognition by T lymphocyte is accompanied by the formation of the molecular structure at the interface with APC called immunological synapse (IS). During this contact, signal transduction is initiated at both, T lymphocyte and APC, sides of the IS. For a long time it was thought that the only function of MHCgpII is presentation of antigen. However, later it was found that stimulation of MHCgpII led to triggering of signals contributing to decision about the further fate of APC. MHCgpII do not have any signaling motifs in their cytoplasmatic domains, and so associated molecules are necessary for the transduction of the signals. This work focuses on B lymphocytes in which the associated molecules are Ig alfa/beta, MPYS, CD19 and CD20. After the stimulation of MHCgpII these proteins mediate signaling events including activation of several families of protein kinases, phospholipase C, mobilization of calcium and activation of transcriptional factors NFAT and AP-1. In B lymphocytes, activities of these pathways may result in proliferation and differentiation but also in the...
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