National Repository of Grey Literature 5 records found  Search took 0.00 seconds. 
Molecular bases of sensitivity to electron transport chain inhibition-induced cell death
Blecha, Jan ; Rohlena, Jakub (advisor) ; Brábek, Jan (referee) ; Pecinová, Alena (referee)
1 Abstract in English Mitochondrial electron transport chain (ETC) targeting shows a great promise in cancer therapy. However, why modern ETC-targeted compounds are tolerated on the organismal level and what are the molecular reasons for this tolerance remains unclear. Most somatic cells are in a non-proliferative state, and features associated with the ETC in quiescence might therefore contribute to specificity. Thus, we investigated the ETC status and the role of two major consequences of ETC blockade, reactive oxygen species (ROS) generation and inhibition of ATP production, in cell death induction in breast cancer cells and in proliferating and quiescent non-transformed cells. First, we characterised the effect of a newly developed ETC inhibitor mitochondria- targeted tamoxifen (MitoTam) in in vitro and in vivo tumour models of breast cancer with varying status of the Her2 oncogene. We document that Her2high cells and tumours have increased assembly of respiratory supercomplexes (SCs) and increased complex I-driven respiration in vitro and in vivo. They are also highly sensitive to MitoTam. Unlike the parental compound tamoxifen, MitoTam efficiently suppressed experimental Her2high tumours without systemic toxicity. Mechanistically, MitoTam inhibits complex I- driven respiration and disrupts respiratory...
L1CAM and its role in cellular senescence
Mrázková, Blanka ; Hodný, Zdeněk (advisor) ; Hubálek Kalbáčová, Marie (referee) ; Rohlena, Jakub (referee)
Cellular senescence, originally defined as irreversible cell cycle arrest, was shown to act in organism as a double-edged sword. On the one hand, cellular senescence is considered an anti-cancer barrier and it beneficially contributes to processes such as wound healing and tissue regeneration. On the other hand, its longer persistence in the organism, usually when not eliminated by the immune system in elder age, cellular senescence contributes to age-related diseases and ageing itself. Moreover, senescent cells emerge as a result of radio- and chemo- therapy and can lead to detrimental effects when not eliminated. There is also accumulated evidence that senescent cells can overcome the proliferation barrier and become malignant (often after a cancer therapy) rendering senescence original definition invalid. In effort to improve the quality of health and life and to minimize the cancer risk after therapies, senescent cells have become one of the most interesting subjects for a targeted therapy. There is a promising potential in developing effective tools, namely drugs specifically killing senescent cells or reducing their detrimental effect (senolytics) that focus on senescent cells elimination in order to rejuvenate the organism, to extend a life span, and to prevent ageing-associated diseases and...
The role of mitochondrial dynamics in cell death
Novotná, Eliška ; Rohlena, Jakub (advisor) ; Alán, Lukáš (referee)
Mitochondria form a dynamic reticulum, which fragments in apoptosis. It is assumed that proteins of mitochondrial dynamics participate in the intrinsic pathway of apoptosis and remodel mitochondrial membranes to release cytochrome c to the cytosol. The most important role in this process is played by Opa1, a protein involved in mitochondrial fusion, and by Drp1, which induces mitochondrial fission. During apoptosis, Opa1 remodels cristae in the inner mitochondrial membrane, which is crucial for effective release of cytochrome c to the cytosol. The role of Drp1 is less clear and is a subject of intense debate. Upon initiation of apoptosis Drp1 is recruited to mitochondria where it facilitates apoptotic pore formation and triggers fission. However, it appears that recruitment of Drp1 is not absolutely required for successful execution of apoptosis. In addition, mitochondrial dynamics is influenced by Bcl-2 family proteins. Recruitment of proapoptotic Bcl-2 proteins to mitochondrial outer membrane leads to inhibition of mitochondrial fusion, which enhances fragmented morphology of mitochondria. Although mitochondrial fragmentation in apoptosis is known for decades, its precise purpose remains to be elucidated.
The role of mitochondrial metabolism in initiation and adaptation to hypoxic conditions.
Rohlenová, Terezie ; Novák, Petr (advisor) ; Rohlena, Jakub (referee)
We can meet pathological hypoxia in the cases of hearth attack, ischemic stroke, but also during tumor invasion, thanks to insufficient angiogenesis. The activation of HIF- 1 factor during hypoxic conditions is crucial for the cell survival. This factor modulates energetic metabolism in favor of fast progressing glycolysis (with the contribution of glutaminolysis) which provides to cell enough ATP and "building blocks", while suppressing Krebs cycle and respiration because of shortage of oxygen. The thesis studies energetic metabolism of HepG2 cells (derived from liver carcinoma) which are cultivated in the media with various energetic substrates, i. e. glucose or galactose (always together with glutamine and pyruvate) under the hypoxic conditions (5% O2). HepG2 cells use particularly oxidative metabolism for ATP and "building blocks" production under the normoxic conditions while hypoxic environment causes metabolic shift in glycemic condition. Interestingly, cells cultured in galactose (glutamine) didn't switch the energy metabolism from oxidative to aerobic glycolysis such as cells cultivated in glucose, although HIF-1 factor was stabilized. We found that enhanced activity and integrity of mitochondria, enhanced maximal capacity and reserve capacity of respiration chain correlates with...
Charakterizace TRAILem indukované, receptor-specifické signalizace v nádorových buňkách.
Peterka, Martin ; Anděra, Ladislav (advisor) ; Rohlena, Jakub (referee)
TNF-related apoptosis-inducing ligand (TRAIL) is a member of TNF family expressed mainly by hematopoietic cells. TRAIL brought significant attention mainly for its ability to trigger apoptosis in a number of cancer cells. In addition to apoptosis, TRAIL can induce several other signaling pathways such as activation of MAP kinases or canonical NF-B signaling. Human TRAIL can bind to five receptors but only two of them (death receptors TRAIL-R1/DR4 and TRAIL-R2/DR5) can trigger TRAIL-mediated apoptotic and non-apoptotic signaling in target cells. Both receptors are ubiquitously expressed on normal and cancer cells, but the relative contribution of DR4 and DR5 to TRAIL-induced signaling is not well known. Using DR4/DR5-specific variants of TRAIL, we examined how individual receptor contributes to the induction of apoptosis and NF-B, JNK, p38, ERK1/2 and TAK1 signaling pathways in selected colorectal cells. We found that in DLD-1 cells, apoptosis and activation of JNKs are mainly mediated by DR4-selective ligand. In TRAIL-resistant HT-29 cells, we show that though DISC formation and activation of caspase-8 proceeds mainly via DR4-specific signaling, activation of NF-B pathway is mainly triggered by DR5 selective ligand. In other cells and analyzed signaling pathways both receptor-specific ligands triggered very...

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7 Rohlena, Jan
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