|
|
Apoptosis of tumor cells : role of TRAIL and caspase 10
Truxová, Iva ; Živný, Jan (advisor) ; Anděra, Ladislav (referee)
One of the key features of cancer cells is the ability to escape programmed cell death (apoptosis). As a mechanism of apoptosis inactivation in cancer cells, somatic mutations of pro-apoptotic genes have been reported in many cancers. Caspase 10 is an initiator caspase whose physiological function remains poorly understood. Also the ability of caspase 10 to substitute for caspase 8 in the death receptors apoptotic pathway is still controversial. However, the fact that some of the mutations found in CASP10 gene was associated with apoptosis defects (79, 81) suggest that caspase 10 could be also important in apoptosis initiation. In our lab, there was found a heterozygous mutation in CASP10 gene of Jurkat (human T-acute lymphoblastic leukemia) clone resistant to TRAIL (J-TR1). This mutation influence the amino acid composition close to the active site of the enzyme. The aim of this thesis was to confirm the mutation by ARMS-PCR and to determine if an overexpression of normal (unmutated) or mutated caspase 10 D in TRAIL sensitive and/or TRAIL resistant Jurkat cells (J-WT and/or J-TR1) will influence TRAIL induced apoptosis. Mutation was confirmed. We created J-WT and J-TR1 stable clones transfected by vector with unmutated or mutated CASP10 D (CASP10 D WT or CASP10 D MUT). CASP10 D MUT overexpression in J-WT...
|
|
|
Analysis of embryotoxic effect of hydrocortisone using chick embryotoxicity screening test (CHEST).
Janíková, Michaela ; Peterka, Miroslav (advisor) ; Hovořáková, Mária (referee)
Cleft lip is one of the most common human birth deffects. Its etiopathogenesis is multifactorial and many aspects of its occurrence remain unknown in the fields of both genetics and teratology. One of the set of known negative external factors causing cleft lip is chemical hydrocortisone. Its effect on cell proliferation is highly heterogeneous and depends on attributes of a specific cell population. In this work we studied the cleft beak origin after the hydrocortisone treatment on the basis of Chick Embryotoxicity Screening Test (CHEST). Our main aim was to detect cell cycle changes in the chick frontonasal process after hydrocortisone injection via flow cytometry analysis. Hydrocortisone caused S phase arrest within a minor subpopulation of highly granular cells with specific cell cycle. This sensitive subpopulation was localized in the areas of previously defined proliferative centers within the frontonasal process using immunohistochemistry of frozen sections. Quantitative analysis of cells in these areas revealed significant decrease of M phase portion in the hydrocortisone treated samples in comparison with the control samples. The TUNEL staining of histological sections was used to determine the apoptotic rate in the frontonasal process. The comparison between the control and the...
|
|
|
Wnt signaling inside out
Doubravská, Lenka ; Kořínek, Vladimír (advisor) ; Stopka, Tomáš (referee) ; Krylov, Vladimír (referee)
Signaling pathways function as molecular instruments mediating cellular response to intrinsic and extrinsic inputs, which can consequently lead to cell division or differentiation on one side and cell death on the other. Molecular network of different pathways enables the intercellular communication and hence the whole organism can exist and function coordinately. The Wnt signaling pathway belongs among evolutionarily old and conserved molecular pathways and acts in many different processes during development. Moreover, it is necessary for maintenance of adult tissues as it participates in regeneration. Diverse malignancies, where repressive components of the Wnt pathway are non-functional, represent seamy side of the scope. This thesis is based on 4 publications covering Wnt signaling on very multifarious levels. Firstly, I focus on processing of Wnt protein which stands at the beginning of the cascade as extracellular morphogen. Secondly, survival effect of Wnt producing fibroblasts on leukemia cells after induction of apoptosis by ligand TRAIL is discussed. The third issue shows novel components of the Wnt signaling pathway and introduces us into nucleus - "bottom" level of the pathway. 1. Fatty acid modification of Wnt1 and Wnt3a at serine is prerequisite for lipidation at cysteine and is...
|
|
|
Molecular mechanisms of apoptosis induced by photodynamic activation in cancer cells
Moserová, Irena ; Králová, Jarmila (advisor) ; Kuželová, Kateřina (referee) ; Kovář, Jan (referee)
Photodynamic therapy (PDT) is a treatment modality for cancer. It combines selective accumulation of chemical compounds, called photosensitizers (PS), with light to irreversibly damage cancer cells via oxidative stress. The main goal of this thesis was to study photosensitizers represented by a unique group of newly synthesized porphyrin derivatives with glycol chain substitution. Glycol-functionalized porphyrins containing one to four low molecular weight glycol chains that are linked via ether bonds to the meta-phenyl positions of meso-tetraphenylporphyrin (mTPP(EG)1-4) were compared with fluorinated (pTPPF(EG)4) and nonfluorinated (TPP(EG)4) derivatives having glycol chains in para-phenyl positions. The cellular uptake and photodynamic activity was significantly dependent on terminal groups of the glycol substituent. Hydroxy glycol porphyrins, in contrast with methoxy glycol porphyrins, exhibited efficient intracellular transport and high induction of apoptosis in tumor cell lines in vitro. After initial testing effective prototype hydroxy ethylene glycol derivatives were selected and analyzed in detail. Para derivatives pTPP(EG)4 and pTPPF(EG)4 accumulated mainly in lysosomes whereas meta derivatives mTPP(EG)1-4 in the endoplasmic reticulum (ER). Position of ethylene glycol chain on the...
|
|
|
Role of STAT3 signalling in oncogenesis and cancer therapy
Machalová, Veronika ; Hodný, Zdeněk (advisor) ; Brábek, Jan (referee)
STAT3 (Signal Transducer and Activator of Transcription 3) is considered to be one of the possible targets of cancer treatment. The ability of STAT3 constitutive activation to form tumors is a foundation of such theories. Additionally, constitutively activated STAT3 is present in many types of cancer with high occurrence, such as breast and prostate carcinoma. This protein is required in normal body cells as well. STAT3 is a transcription factor targeting many genes that are essential for the cell. STAT3 is activated by phosphorylation of its tyrosine residue and homodimerization. Proteins transcribed with help of STAT3 function in cell cycle progression, cell growth, replication, negative regulation of apoptosis, and other roles, typical for cancer. Moreover, STAT3 is modulating mitochondrial function and maintaining ROS production in mitochondria, but in form of transcriptionally inactive monomers. The purpose of this Thesis is to review known data about STAT3 in oncogenesis and by that, to show STAT3 has great potential to become the target of cancer treatment. This Thesis contains a short overview of known STAT3 inhibitors as well. Key words: Signal Transducer and Activator of Transcription 3 (STAT3), JAK/STAT3 pathway, constitutive activation, cancer, tumor, inhibitor, mitochondria, apoptosis
|
|
|
Cytochrome c and its role in apoptosis
Rajsiglová, Lenka ; Kalous, Martin (advisor) ; Švadlenka, Jan (referee)
Cell energetic metabolism and cell survival are strictly controlled by pathways in which cytochrome molecules play a central role, in particular cytochrome c. It is localized in the mitochondrial intermembrane space with other molecules cooperating in keeping energetic metabolism. Permeabilization of outer mitochondrial membrane by proteins from Bcl-2 family or changes in Ca2+ levels causes cytochrome c release into cytosol. In cytosol cytochrome c interacts with other pro-apoptotic proteins (Apaf-1, procaspase-9) cooperating to form apoptosome and phosphatidylserine. As a result of these interactions, the cell is going to apoptosis. This bachelor thesis summarizes the current state of knowledge of these processes. In the first part it focuses on the biosynthesis of cytochrome c, further on the mechanisms of its releasing from mitochondria and its interactions with other proteins within apoptosis including options of regulation of these processes.
|
|
|
Role of endocytosis and endosomal acidification in TRAIL-induced apoptosis
Hradilová, Naďa ; Anděra, Ladislav (advisor) ; Kovář, Jan (referee)
TRAIL (TNF-related apoptosis inducing ligand) became known for its ability to selectively eliminate cancer cells. This ligand is a member of the TNF (tumor necrosis factor) ligands family and triggers extrinsic apoptotic pathway by binding of its death receptor 4 or 5 (DR4/5), and subsequent formation of death-inducing signalling complex (DISC). This signalling complex is required for successful transmission of apoptotic signal and activation of proximal caspases. However, regulation of the initial steps leading to activation of caspases is still not fully understood. Endocytosis of a TRAIL- DR4/5-DISC complex can be one of modulators of the initiation of extrinsic apoptotic pathway. Recent studies show controversial data documenting that endocytosis of TRAIL receptosomes can in cell type specific manner either positively or negatively influence TRAIL-induced apoptotic signalling. In this study, we focus on the analysis of a role of endocytosis and acidification of endosomal compartments during TRAIL-induced apoptosis in human colorectal cancer cell lines. Our results support the view that both clathrin-dependent endocytosis of TRAIL receptosome and endosomal acidification positively affect activation of caspases during the early stages of TRAIL-induced apoptosis. Inhibition of endocytosis or endosomal...
|
|
|
Effect of cancer-associated fibroblasts on the survival, proliferation and invasiveness of cancer cells.
Nováková, Gita ; Anděra, Ladislav (advisor) ; Brábek, Jan (referee)
Tumour microenvironment, in addition to cancer cells themselves, represents important structural and functional part of the tumour. Similarly to the normal organs tumour microenvironment comprises several cell types (fibroblasts, immune cells, endothelial cells etc.) and non-cellular components, particularly extracellular matrix. All of them form favourable conditions for the growth, proliferation, protection from the immune system- mediated destruction and nutrition of cancer cells. Cancer associated fibroblasts (CAFs) represent the most abundant cell type of tumour microenvironment. Their origin can be traced to local normal fibroblasts, endothelial cells or epithelial cells and the transition into the CAFs phenotype is influenced with several factors secreted by cancer cells (particularly TGF-β). In contrast to fibroblasts activated during wound healing newly formed cancer associated fibroblasts expressing α-SMA are not subsequently eliminated from the respektive tissue. They persist and produce a number of pro-tumorigenic factors - SDF-1, HGF, IGF-1, IL-6, VEGF, PDGF-C, TGF-β, MMPs etc. CAFs and their secreted factors target several signalling pathways enhancing basic characteristics of the tumour, so called Hallmarks of Cancer. Cancer associated fibroblasts promote proliferation and invasiveness of...
|
|
| |
|
|
Apoptosis of pancreatic β-cells induced by endoplasmic reticulum stress and its mechanisms in type 2 diabetes
Glatzová, Daniela ; Němcová, Vlasta (advisor) ; Libusová, Lenka (referee)
Increasing incidence of type 2 diabetes represents one of the principal threats to human health in the 21st century. Strong evidence indicates that the rise in incidence of type 2 diabetes is correlated with increasing levels of obesity and that important factor playing role in the development of this disease is an elevation in circulating glucose and fatty acids. Chronically increased concentration of these nutrients was shown to induce apoptosis of pancreatic beta-cells that subsequently contributes to diabetes progression. Despite intensive research, molecular mechanisms underlying this beta-cells loss are still unclear. However, there is increasing evidence that one of the key processes involved in glucose and fatty acid-induced beta-cell death is induction of endoplasmic reticulum stress. The aim of this work is to summarize the recent knowledge about induction of apoptosis by endoplasmic reticulum stress in pancreatic beta-cells in relation to type 2 diabetes.
|
guest ::
