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The role of cell polarity signaling in the plasticity of cancer cell invasiveness
Gandalovičová, Aneta ; Brábek, Jan (advisor) ; Cvrčková, Fatima (referee)
Throughout the last few years cancer research has focused on studying the origin of secondary tumors, i.e. metastases, which are a direct outcome of the ability of cancer cells to disseminate from the primary tumor and invade the adjacent tissue. Generally, cancer cells migrate by two distinct mechanisms- amoeboid or mesenchymal. Whereas the mesenchymal migration mode can be described as "path generating", the amoeboid mode resembles a "path finding" way of migration. Both types of invasion are regulated by divergent signaling pathways that are closely related to cell polarity and cytoskeleton reorganization. Responsible for cell polarization are not only the polarity complexes Par, Scribble and Crumbs, but also phosphoinositides and Rho GTPases Rac, Rho and Cdc42, which, additionally, regulate the dynamics of the cytoskeleton. By a mutual interplay they regulate cell motility. It cannot come as a surprise that their deregulation commonly results in tumorigenesis. A more thorough comprehension of the signaling pathways leading to cancer cell invasiveness is a necessary step towards understanding the complex problem of metastasis. Key words: invasiveness, amoeboid, mesenchymal, cell polarity, motility, Rho GTPases, polarity complexes
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The analysis of cancer invasion plasticity in a 3D environment
Škarková, Aneta ; Brábek, Jan (advisor) ; Anděra, Ladislav (referee) ; Bryja, Vítězslav (referee)
iii Abstract Cells have evolved multiple mechanisms of cellular motility ranging from the migration of large cell cohorts to specialized migration of individual cells. The wide range of invasion modes has been exploited by cancer cells to their advantage, which has rendered the metastatic process so difficult to defeat. To allow for a better understanding of cancer invasion plasticity, we have employed studies on cancer cells that adopt the proteolytically active, adhesion-dependent, elongated mesenchymal invasion mode, the protease-independent, low adhesion, rounded amoeboid invasion mode, or combination of both. To study invasion plasticity directly, we have established two model systems of the mesenchymal- amoeboid transition (MAT) that allow for regulated induction of MAT in 3D in vitro environments. Using these systems, MAT was induced in HT1080 fibrosarcoma cells and the acquisition of a motile, invasive amoeboid phenotype was confirmed. We then observed the mesenchymal and amoeboid invasion strategies within 3D collagen in more detail using a digital holographic microscope. Further, HT1080 cells before and after MAT were subject to high throughput proteomic and transcriptomic studies. Comparison of gene expression and protein levels of mesenchymal and amoeboid cells disclosed an inflammatory-like...
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The plasticity of melanoma cell invasiveness
Gandalovičová, Aneta ; Brábek, Jan (advisor) ; Truksa, Jaroslav (referee)
and keywords: During metastasis, cancer cells can invade the extracellular matrix using various strategies. When invading individually, they employ either the amoeboid invasion mode, during which the cell body dynamically deforms by enhanced contractility to squeeze through pores within the matrix, or protease dependent mesenchymal migration that takes advantage of the possibility to digest the surrounding matrix. Cells migrating in one mode can actively switch to the other by mesenchymal-amoeboid (MAT) or amoeboid-mesenchymal transitions (AMT). This enables escape mechanisms and considerably complicates anti-metastatic treatment. It is well known that Rho GTPases are master regulators of cytoskeleton re-arrangements and thus, unsurprisingly, play a major role in both invasion modes and can directly drive the transitions. However, upstream activation of these pathways is still largely unclear. This thesis aimed to optimize 3D conditions suitable for studying plasticity of cell invasion in vitro, establish AMT and MAT in melanoma cells based on manipulation of Rho GTPases and verify novel candidates regulating cell invasion plasticity based on previous RNA sequencing of cells before and after MAT. Last, by synthesis of published data, results from sequencing and new findings presented in this...
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The role of cell polarity signaling in the plasticity of cancer cell invasiveness
Gandalovičová, Aneta ; Brábek, Jan (advisor) ; Cvrčková, Fatima (referee)
Throughout the last few years cancer research has focused on studying the origin of secondary tumors, i.e. metastases, which are a direct outcome of the ability of cancer cells to disseminate from the primary tumor and invade the adjacent tissue. Generally, cancer cells migrate by two distinct mechanisms- amoeboid or mesenchymal. Whereas the mesenchymal migration mode can be described as "path generating", the amoeboid mode resembles a "path finding" way of migration. Both types of invasion are regulated by divergent signaling pathways that are closely related to cell polarity and cytoskeleton reorganization. Responsible for cell polarization are not only the polarity complexes Par, Scribble and Crumbs, but also phosphoinositides and Rho GTPases Rac, Rho and Cdc42, which, additionally, regulate the dynamics of the cytoskeleton. By a mutual interplay they regulate cell motility. It cannot come as a surprise that their deregulation commonly results in tumorigenesis. A more thorough comprehension of the signaling pathways leading to cancer cell invasiveness is a necessary step towards understanding the complex problem of metastasis. Key words: invasiveness, amoeboid, mesenchymal, cell polarity, motility, Rho GTPases, polarity complexes
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The role of NG2 glycoprotein in the regulation of Rho/ROCK signaling.
Kratochvílová, Magdalena ; Rösel, Daniel (advisor) ; Libusová, Lenka (referee)
NG2 is a transmembrane glycoprotein mainly expressed in developing tissue, and often re-expressed in tumor cells. NG2 glycoprotein is an important regulator of cell migration and adhesion. Increased expression of NG2 enhances the metastatic potential of cancer cells. However, the molecular mechanisms of these processes are still not fully understood. An increasing number of evidences, in recent years, have shown that NG2 can be responsible for Rho/ROCK activation, which is essential for effective amoeboid invasiveness. In this thesis, we analysed the role of NG2 glycoprotein, especially the role of its PDZ- binding motif on amoeboid phenotype induction, and activation of Rho/ROCK signaling. Our results demonstrate the importance of the NG2 PDZ-binding motif on mesenchymal- amoeboid transition of cells in a 3D environment. Surprisingly, they show that the expression of both the NG2 cytoplasmatic domain and the truncated version, lacking the PDZ-binding motif, do not change the amount of Rho-GTP or the activation of the Rho/ROCK signaling pathway in 2D.
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