Death in all types of melanomas is generally caused by metastasis. Uveal melanoma (UM) is the most common intraocular melanoma, there are currently no (patient-derived) animal models that... Show moreDeath in all types of melanomas is generally caused by metastasis. Uveal melanoma (UM) is the most common intraocular melanoma, there are currently no (patient-derived) animal models that faithfully recapitulate metastatic dissemination of UM. Here we generate embryonic zebrafish models for both the primary and disseminated stage of ocular melanoma. In doing so we can recapitulate the etiology of cancer in its totality. Subsequently, we developed a patient-derived zebrafish xenograft (zf-PDX) model, using spheroid cultures generated from metastatic and primary UM tissues. Harnessing this versatile model, we reveal high sensitivity of circulating UM cells to ferroptosis induction in vivo by Erastin and RSL3, implicating ferroptosis as a new potential therapy in metastatic UM.Increased melanin levels in cutaneous melanoma are associated with decreased patient survival. Melanin levels in primary uveal melanoma patient cells positively correlate with their metastatic potential in zebrafish. Modulation of melanin levels of pan-melanoma cells results in enhanced/reduced metastatic potential upon increased or decreased melanin levels, respectively. Melanin depletion sensitizes melanoma cells to ferroptosis inducers in zebrafish leading to a decreased metastatic burden. Collectively, our data identify melanin biosynthetic enzymes as potential future target to treat melanoma and show that melanin protects metastasizing melanoma cells from ferroptosis. Show less
Cells communicate in multicellular organisms; by secreting and sensing signals, in order to adjust their behavior to the environment. Extracellular signals such as cytokines and growth factors bind... Show moreCells communicate in multicellular organisms; by secreting and sensing signals, in order to adjust their behavior to the environment. Extracellular signals such as cytokines and growth factors bind to cell surface receptors and trigger the activation of multiple protein signal transduction cascades that mediate cellular responses such as proliferation, differentiation, apoptosis and motility. The Mitogen-activated protein kinase (MAPK) family is a group of homologous proteins forming several linear signal transduction pathways. The MAPK family is conserved among eukaryotes and most vertebrates contain at least 14 MAPKs. We are interested in the molecular mechanisms of MAPK signalling that facilitate proper development of the zebrafish embryo. The zebrafish is an excellent model to delineate MAPK associated embryonic processes. The bodyplan is completed within 24hours and within a week most organs are formed. With the current available zebrafish tools molecular mechanisms could be identified and linked to cellular processes and morphological observations. We constructed constitutive active zebrafish Erk2 mutants for identification of new signalling events. We completed expression analysis of all P38 isoforms by expression analysis of the P38_ and P38_ isoforms. We also performed a comparative study between P38_ and Erk2 MAPK in gastrulation. Finally, We addressed the role of P38_ in zebrafish angiogenesis. Show less
Analysis of the transcriptome, the total of all expressed RNA transcripts in a cell or an organism, contributes to our understanding of gene regulation during development and disease processes and... Show moreAnalysis of the transcriptome, the total of all expressed RNA transcripts in a cell or an organism, contributes to our understanding of gene regulation during development and disease processes and is therefore of great importance in the field of genomic research. This thesis focuses on the analysis of transcriptome complexity during infectious disease and cancer. The zebrafish was applied as an immunological model organism, due to the remarkable similarities of its immune system to that of human. The studies took advantage of novel opportunities for transcriptome profiling provided by recent developments in microarray and next generation sequencing technology that have made an enormous impact on biology. In addition to studying expression of protein coding genes, the work addressed regulatory functions of microRNAs, small non-coding RNAs playing important roles in the function of the immune system and other processes. The transcriptome data provide a valuable reference set of infection-responsive genes and microRNAs in zebrafish models and have identified microRNAs conserved between human and zebrafish liver cancer. These genomic data sets provide a strong basis for future applications of zebrafish as an infection and cancer model and contribute to the understanding of pathogenesis and the development of novel strategies for disease treatment. Show less
