This thesis represents a comprehensive investigation into the control of cancer stemness and metastatic initiation using a combination of advanced zebrafish xenograft models and in vitro assays.... Show moreThis thesis represents a comprehensive investigation into the control of cancer stemness and metastatic initiation using a combination of advanced zebrafish xenograft models and in vitro assays. The discoveries made and the evaluation of drug efficacy provide valuable insights for the development of novel therapeutic approaches in the fight against metastatic cancer. Show less
Prostate cancer (PCa) is one of the most prevalent cancer in males. Although the majority of the patients can benefit from the present clinical treatments, 20%-30% of the patients who originally... Show moreProstate cancer (PCa) is one of the most prevalent cancer in males. Although the majority of the patients can benefit from the present clinical treatments, 20%-30% of the patients who originally respond to the therapy still develop incurable, castration-resistance bone metastases, which is a main cause of death in PCa . In this thesis, I combined an advanced zebrafish xenograft model with in vitro cellular approaches and mice xenografts to study the early stage of PCa metastasis. Using this comprehensive esearch platform, I identified multiple key signaling pathways that play essential roles in promoting the onset of PCa metastatis. The pathways I discovered include Cripto-associated EMT plasticity, CDC-42-N-Wasp-Cortactin associated mechanosensing and mechanotransduction, microenvironment dependent NF-ĸB-Activin A signaling pathway, and AMPK-Autophagy dependent metabolic stress coping pathway. Show less
Cells receive mechanical cues from the surrounding extracellular matrix (ECM). This has a strong impact on physiology and pathology in a wide range of biological settings. Integrin receptors couple... Show moreCells receive mechanical cues from the surrounding extracellular matrix (ECM). This has a strong impact on physiology and pathology in a wide range of biological settings. Integrin receptors couple the ECM to the intracellular cytoskeleton across the cell membrane through a dynamic multiprotein adhesion complex and mediate bidirectional force transmission. In this research the mechanism of cellular mechanotransduction and its role in aspects of cancer progression are studied, focusing on integrins and other integrin associated proteins. We find that the integrin expression profile of cells regulates the orientation and dynamics of force transmission at cell-matrix adhesions. Additionally, using a novel method to quantify the abundance of a molecule in a cellular complex, we show that substrate rigidity modulates the association between traction forces and molecular composition of cell-matrix adhesions. Using cell microprinting in 3D ECM scaffolds, we determine the relation between tumor-induced remote ECM network orientation and angiogenesis. Lastly, genes that regulate cancer cell migration, force application, and adhesion dynamics are identified. Overall, the work described in this thesis unravels the role of cellular mechanotransduction in different aspects of cancer progression and reveals how the molecular composition of cell-matrix adhesions relates to traction force generation. Show less
Ewing sarcoma (ES) is a special type of bone cancer, first described by Dr. James Ewing in his paper __Diffusive endothelioma of bone__. Today Ewing sarcoma represents the second most common bone... Show moreEwing sarcoma (ES) is a special type of bone cancer, first described by Dr. James Ewing in his paper __Diffusive endothelioma of bone__. Today Ewing sarcoma represents the second most common bone cancer among adolescents and young adults. Contrary to the positive achievement in treatment of localized tumors, the long-term (5-years) survival for Ewing sarcoma patients with metastasis, however, remain below the 30% mark. In this thesis a report on experimental work aiming for a better understanding of the mechanisms underlying Ewing sarcoma metastasis is presented. Two distinct mechanisms are investigated: (1) a biochemical approach in which the initial steps in the CXCR4 signaling cascade are followed, and (2) a biophysical approach in which the guidance of Ewing sarcoma metastasis by the stiffness of their microenvironment is demonstrated. The results presented in this thesis provide deeper insights into the mechanisms controlling signaling of the chemokine receptor CXCR4 and into the role of the micro-environment in Ewing sarcoma cells behavior.Through various experimental approaches it was shown that both biochemical and biophysical guidance control how Ewing sarcoma develops into its distinct metastatic phenotype. Show less
We have developed novel fluorescence bio-imaging based automated models to screen for novel candidate targets involved in prostate cancer metastasis. Utilizing these models and adopting a... Show moreWe have developed novel fluorescence bio-imaging based automated models to screen for novel candidate targets involved in prostate cancer metastasis. Utilizing these models and adopting a functional genomics based approach; we identified SYK as a novel regulator of prostate cancer progression. We also identified functional involvement of MST1R in regulating the progression of prostate cancer. For both of these targets, there is supporting human clinical data to validate our results in prostate cancer. Show less
Despite extensive studies to unravel molecular mechanisms underlying breast cancer metastasis, still 3500 women die of the results of this disease in the Netherlands each year. Improving our... Show moreDespite extensive studies to unravel molecular mechanisms underlying breast cancer metastasis, still 3500 women die of the results of this disease in the Netherlands each year. Improving our understanding of metastasis formation remains a challenge for further drug development. The scope of this thesis is the identification of novel candidate metastasis genes, with a main focus on candidate genes affecting tumor cell migration. For that purpose, a live cell imaging-based random cell migration assay that is suitable for screening has been developed. In addition, a mouse breast cancer model that allows to study tumor cell autonomous processes of metastasis formation is described. A RNA-interference tumor cell migration screen has been done and resulted in the identification of novel regulators of tumor cell migration that show clinical relevance in a breast cancer patient cohort. In addition, focused research has been conducted on two previously identified candidate metastasis genes to determine their role in breast cancer metastasis. Show less
The aim of this thesis is to address how integrin-mediated signaling regulates cellular processes that have profound effects on cell morphology, motility, cancer metastasis, and FN fibrillogenesis,... Show moreThe aim of this thesis is to address how integrin-mediated signaling regulates cellular processes that have profound effects on cell morphology, motility, cancer metastasis, and FN fibrillogenesis, and how these findings can be utilized for relevant medical purposes or advancement of drug discovery. Show less
Vertebrates, especially mammals, have long been used as research models in the study of human diseases. During this research we have demonstrated the usefulness of a relatively new animal model,... Show moreVertebrates, especially mammals, have long been used as research models in the study of human diseases. During this research we have demonstrated the usefulness of a relatively new animal model, the zebrafish, in understanding human disease formation, progression and even treatment. We first analysed the impact that exposure to constant chronic hypoxia has in the zebrafish heart, both at the morphological and genetic levels. On chapters three and four we demonstrated the worth of the zebrafish larvae in understanding metastasis formation and progression. Whereas in chapter three we focused on the use of the zebrafish as a model to rapidly test the metastatic behaviour of human pancreatic cancer cell lines and primary human tumours; on chapter four we researched the role of retinoic acid receptor antagonist, and mir10-a, as a potential new anti-cancer therapy for pancreatic adenocarcinoma. Show less
Despite major advances in breast cancer diagnostics and treatment over the years, the disease is still a leading cause of death in women worldwide. Primary breast tumors can be treated relatively... Show moreDespite major advances in breast cancer diagnostics and treatment over the years, the disease is still a leading cause of death in women worldwide. Primary breast tumors can be treated relatively well with radiation, surgery, chemotherapy or a combination of these treatments. The occurrence of distant metastases derived from the primary tumor however, results in a considerable decrease in disease prognosis. Metastasis formation occurs through a series of distinct cell biological steps (outlined above). Understanding the molecular mechanisms that underlie each of these steps will help in the development of more successful anti-metastasis treatments. In this thesis, both in vitro and in vivo studies are described that aim at unraveling some of the processes involved in metastasis formation: signaling by components of the focal adhesions and cell migration. Show less
In het proefschrift van Martine van Miltenburg wordt het onderzoek naar de rol van FAK en annexine A1 in borstkankerontwikkeling en uitzaaiing (metastasering) beschreven. E__n van de... Show moreIn het proefschrift van Martine van Miltenburg wordt het onderzoek naar de rol van FAK en annexine A1 in borstkankerontwikkeling en uitzaaiing (metastasering) beschreven. E__n van de sleutelprocessen bij de metastasering is de verandering van het rustige fenotype van kankercellen naar het beweeglijke fenotype. Een belangrijke ontdekking is dat het eiwit annexine A1 een belangrijke rol speelt in metastasering van basale borstkanker. Verhoogde expressie van annexine A1 draagt bij aan beweeglijkheid en daarmee agressief gedrag van tumorcellen. Hoe hoger de expressie van annexine A1, hoe meer uitzaaiingen, simpel gezegd. Wanneer annexine A1 wordt uitgeschakeld in deze cellen verandert de cel van het agressieve gedrag naar een ___rustige___ tumorcel, en ontstaan er beduidend minder uitzaaiingen. Ondanks de veelbelovende resultaten is het geen optie om remming van annexine A1 als anti-kanker therapie te gebruiken omdat annexine A1 ook in gezonde lichaamscellen een belangrijke functie heeft. Maar de onderzoekers denken wel dat annexine A1 een ___marker___ voor basale borstkanker kan worden. Doordat annexine A1 specifiek in basale borstkanker verhoogd tot expressie komt zou het als marker wellicht goed gebruikt kunnen worden om dit relatief agressieve type borstkanker type te bepalen bij pati__nten. Show less
Tumor cell migration and invasion are essential steps in cancer metastasis. Better understanding of the molecular mechanisms and function of the individual proteins affecting this behaviour is... Show moreTumor cell migration and invasion are essential steps in cancer metastasis. Better understanding of the molecular mechanisms and function of the individual proteins affecting this behaviour is essential to define potential novel drug targets to combat cancer. In general, cells in a normal tissue environment are attached to the extra-cellular matrix (ECM) and to each others. The interactions with the ECM are mediated through integrin adhesion receptors. Matrix adhesions are the physical link between the ECM and the actin cytoskeleton and are important for survival, proliferation, differentiation and migration. These cytoplasmic structures are composed of various signaling (phosphatases and kinases) and structural proteins that form the so-called __integrin-adhesome__. The spatial and temporal regulations of these components determine the type of matrix adhesion, their behaviour and finally the fate of the cell. For instance, resting cells such as renal epithelial cells show enlarged and stable focal adhesions as well as tight cell-cell contacts. In contrast, tumor cells which are able to invade and metastasize, lose their interactions with adjacent cells and show fast, small and highly dynamic matrix adhesions. In this thesis, we set up technologies and investigated the molecular mechanisms of the matrix adhesions dynamics in relation to tumor cell behaviour both in vitro and in vivo situation. Show less
Cutaneous and uveal melanoma are malignant tumours with no treatment available once the metastases occur. Despite both melanomas are highly immunogenic, and often despite the presence of potent... Show moreCutaneous and uveal melanoma are malignant tumours with no treatment available once the metastases occur. Despite both melanomas are highly immunogenic, and often despite the presence of potent anti-tumour immune cells in patients__ blood, in more than 95% of patients, tumour growth remains unaffected. Hereby we investigate the mechanisms that help melanomas to escape from the spontaneous or activated by vaccination cytotoxicity of T lymphocytes and discuss the impact of local microenvironment created by melanoma, focusing on the role of immunomodulatory dendritic cells. Show less
In order to form a distant metastasis, a cancer cell has to migrate out of the primary tumor, intravasate into a blood or a lymphatic vessel, subsequently survive in the absence of cell-cell and... Show moreIn order to form a distant metastasis, a cancer cell has to migrate out of the primary tumor, intravasate into a blood or a lymphatic vessel, subsequently survive in the absence of cell-cell and cell-matrix interactions, extravasate the blood or lymphatic vessel, migrate through the target organ and finally proliferate to grow out into a full metastasis. During all of these processes, specific kinases are involved in the concerted activation of distinct signaling pathways. We hypothesised that the protein tyrosine kinase FAK plays a crucial role in one or multiple of the processes involved in the formation of metastases. Therefore, the overall aim of the studies described in this thesis was to investigate the role of the non-receptor protein tyrosine kinase FAK in the distinct processes involved in tumorigenesis and metastasis and to unravel the involved downstream signaling pathways. Moreover, the potential of a combined therapy of the inhibition of FAK and exposure to the cytostatic doxorubicin was tested, as well as dissection of the intracellular events downstream of FAK. Show less
