|
|
Horizontal transfer of mitochondria and its role in carcinogenesis
Nováková, Anna ; Neužil, Jiří (advisor) ; Rösel, Daniel (referee)
Mitochondria are essential organelles as they produce most ATP to support cellular activities, synthesize critical metabolic factors and are involved in lipid and phospholipid metabolism as well as calcium signalling. The oxidative phosphorylation (OXPHOS) system, present at the inner mitochondrial membrane, plays role in regulation of cellular metabolism and survival of cancer cells. Recent studies show importance of OXPHOS in growth of cancer cells via regulation of the de novo pyrimidine synthesis pathway. Dihydroorotate dehydrogenase (DHODH), a flavoprotein localized in the inner mitochondrial membrane, converts dihydroorotate (DHO) to orotate within the de novo pyrimidine synthesis pathway, generating electrons that are transferred, via redox- cycling of ubiquinone, to complex III (CIII) of respiratory chain. Since DHODH is functionally linked to CIII activity, impairment of respiration results in reduced activity of DHODH and pyrimidine synthesis. Therefore, mitochondrial damage or mutation in mitochondrial DNA (mtDNA) leads to decreased respiration, cancer cell proliferation and delay of tumour growth. As a compensation for damaged mitochondria, horizontal transfer of functional mitochondria from donor somatic cells to the mitochondria-damaged tumour cells was demonstrated. This...
|
|
|
Analyzing the role of the p130Cas SH3 domain in p130Cas-mediated signaling
Gemperle, Jakub ; Rösel, Daniel (advisor) ; Vomastek, Tomáš (referee) ; Truksa, Jaroslav (referee)
The adaptor protein p130Cas (CAS, BCAR1) represents a nodal signaling platform for integrin and growth factor receptor signaling, and influences normal development and tissue homeostasis. Its altered expression drives many pathological conditions including tumor growth, metastasis and drug resistance in many cancer types. How p130Cas contributes to many of these pathologies is still poorly understood. Therefore, the overall aim of my PhD work was to provide new insights to p130Cas signaling and its regulation. The SH3 domain is indispensable for p130Cas signaling, but the ligand binding characteristics of the p130Cas SH3 domain, and the structural determinants of its regulation were not well understood. To be able to study various aspects of p130Cas signaling we identified an atypical binding motif in p130Cas SH3 domain by establishing collaborations with Dr Veverka (Structural biology) and Dr Lepšík (Computational biochemistry; Academy of Sciences, CZ) which gave new insight into this binding interface. Through these collaborations I generated chimeras of p130Cas SH3 domain with its ligands for structural NMR analysis and learned how to visualize and analyze structures. Furthermore, my work expanded our knowledge of p130Cas SH3 ligand binding regulation and led to a novel model of Src-p130Cas- FAK...
|
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
Role of CCH domain in localization and signaling of an adaptor protein CAS
Braniš, Jaroslav ; Rösel, Daniel (advisor) ; Gregor, Martin (referee)
Focal adhesions are cell structures that are formed between cell and the surrounding environment. The cell receives through focal adhesions important information about the chemical composition of the surrounding environment. In addition, focal adhesions are crucial for the transmission of forces that are generated inside the cell and the forces that affect the cell from the outside. CAS is the focal adhesion protein, which has been shown to regulate the actin cytoskeleton and the ability of the cells to generate forces needed for the surrounding environment deformation and cell migration. CAS is additionally molecular mechanosensor which senses mechanical forces and convert them into biochemical information, which is transmitted further into the cell. Localization of CAS in focal adhesions is necessary for its functioning. For this work, we have prepared a set of variants of CAS protein which was mutated in regions where are situated the N-terminal SH3 domain and a C-terminal CCH domain, which play the role of so-called anchoring domains. CAS protein variants were used to elucidate the role of anchoring domains for the localization and dynamics of CAS in focal adhesions and for the ability of the cells to generate traction forces. Keywords: CAS, SH3 domain, CCH domain, FAT domain, focal adhesions,...
|
|
|
The Role of the Tumour Microenvironment on Melanoma Cell Invasiveness
Jobe, Njainday ; Rösel, Daniel (advisor) ; Kořínek, Vladimír (referee) ; Bušek, Petr (referee)
Cancer cell invasion and metastasis are hallmarks of cancer. It is becoming apparent that the interaction between cancer cells and the surrounding microenvironment are involved in their ability to invade and metastasise. In general, cancer cells can either migrate individually, in an amoeboid or mesenchymal manner, or collectively. The first aim of this thesis was to analyse the role of NG2 in amoeboid to mesenchymal transition (AMT) and Rho/ROCK signalling. We found that NG2 promotes an amoeboid morphology, and increased invasiveness, in a Rho-dependent manner. Secondly, we analysed the role of the major tumour microenvironment (TME) component, cancer-associated fibroblasts (CAFs), on melanoma cell invasiveness. We found the CAF interaction with melanoma cells leads to increased levels of interleukin-6 (IL-6) and IL-8, and this leads to increased invasiveness. Simultaneous blocking of IL-6 and IL-8, using neutralising antibodies, inhibits CAF-dependent invasion. Further analysis of another major component in the melanoma TME, keratinocytes, has highlighted the importance of the tumour cell niche in invasion. Our results indicate that cancer cells have the ability to change morphology, and that the TME plays an important role in melanoma cell invasiveness. Metastatic melanoma treatment has proven...
|
|
|
Crosstalk of PKN3 and p130Cas/BCAR1 signaling
Dibus, Michal ; Rösel, Daniel (advisor) ; Voller, Jiří (referee)
Both p130Cas and PKN3 are important regulators of cellular signaling deregulation of which leads to malignant behavior of cancer cells. Recently we have found that SH3 domain of p130Cas mediates interaction with proline rich region of PKN3 suggesting their possible cooperation in regulation of these processes. In this work we have focused on the phosphorylation of p130Cas by PKN3 and identified serine 498 (S498) within the serine rich domain of p130Cas to be phosphorylated by PKN3 in vitro. Given that S498 is localized within the 14-3-3 binding motif and its phosphorylation is required for interaction of p130Cas with 14-3-3 proteins, we propose potential existence of novel PKN3/p130Cas/14-3-3 signaling axis. In the second part of the work we have studied this pathway in response to antiestrogen treatment in estrogen receptor positive breast cancer cell line MCF7. Although we have shown inactivation of PKN3 occurs as an early response to tamoxifen treatment, we do not rule out its possible role in further promotion of resistance to antiestrogens. Furthermore, understanding the signaling triggered by interaction of PKN3 with p130Cas and its possible downstream effects on promoting malignant growth of cancer cells would help in finding novel therapeutic targets.
|
guest ::
