Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths in the western world and an improved understanding of the molecular pathways involved in CRC could potentially allow... Show moreColorectal cancer (CRC) is one of the leading causes of cancer-related deaths in the western world and an improved understanding of the molecular pathways involved in CRC could potentially allow improved prediction and personalized therapy. The BMP pathway is known to be crucial for the maintenance of intestinal homeostasis and deregulation of this pathway is known to contribute to colorectal cancer formation. The studies presented in this thesis provide evidence that the BMP pathway is an important homeostatic pathway and that, both in normal tissue and in cancer, BMP signaling is influenced by (cancer-associated) fibroblasts. The outcome of BMP signaling on the epithelial cells appears to be dependent on the bioavailability of BMPs and, importantly, on the presence of a functional intracellular BMP pathway. Show less
Integrins play an essential role in multicellular life by connecting cells to the extracellular matrix. This thesis provides an overview of the distinct types of integrin-containing cell adhesion... Show moreIntegrins play an essential role in multicellular life by connecting cells to the extracellular matrix. This thesis provides an overview of the distinct types of integrin-containing cell adhesion complexes present in epithelial cells. By employing BioID we succesfully characterized the composition of focal adhesions, flat clathrin lattices, and hemidesmosomes. In addition, we investigated the role of different adhesion complexes in (cancer) cell adhesion, migration, polarity, and proliferation and in mechanotransduction. Show less
Immunotherapy is a highly promising treatment option for cancer. At present, only a small proportion of cancer patients benefits from immunotherapeutic interventions. There is an unmet need to... Show moreImmunotherapy is a highly promising treatment option for cancer. At present, only a small proportion of cancer patients benefits from immunotherapeutic interventions. There is an unmet need to understand which factors determine a patient’s response to immunotherapy as well as to develop novel immunotherapeutic approaches that address shortcomings of current immunotherapies.In this thesis, we have performed an unprecedented characterization of immune cell subsets participating in anti-tumor responses in colorectal cancer and pancreatic ductal adenocarcinoma with different single-cell technologies. Most cancer immunology research studied the role of cytotoxic T cells in both cancer types, while a comprehensive analysis of both innate and adaptive components of cancer immunity was largely lacking. With such an approach, we demonstrated an important involvement of understudied unconventional (γδ T cells) and innate (innate lymphoid cells (ILCs)) immune effector cells in anti-tumor immunity. These immune subsets displayed cytotoxic activity and showed potential for therapeutic exploitation. Further studies will focus on their functional characterization and potential reconversion into a therapeutic agent.This thesis resulted from the collaboration between research groups led by Noel de Miranda (Pathology, LUMC) and Frits Koning (Immunology, LUMC), and underscores the relevance of applying single-cell technologies for the study of complex biological systems. Show less
This thesis focused on risk factors and outcomes based on colorectal cancer auditing and aimed to provide new insights into outcome indicators, treatment modalities, and outcomes in high-risk... Show moreThis thesis focused on risk factors and outcomes based on colorectal cancer auditing and aimed to provide new insights into outcome indicators, treatment modalities, and outcomes in high-risk patients, and to monitor outcomes after implementation of minimally invasive surgery. Nationwide population-based studies with data of the Dutch ColoRectal Audit (DCRA) were used to provide information regarding colorectal cancer care on different levels (hospital, national, and international level) and in specific high-risk subpopulations. Show less
This thesis highlights, firstly, the importance of early CRC detection by presenting results of a CRC diagnostic proteomic biomarker signature with high discriminative power. Secondly, a strong... Show moreThis thesis highlights, firstly, the importance of early CRC detection by presenting results of a CRC diagnostic proteomic biomarker signature with high discriminative power. Secondly, a strong robust, independent prognostic tumor stroma ratio (TSR) biomarker, which confirms to be of important clinical value. The TSR has the ability to stratify colon cancer patients according to their prognostic outcome in a highly reproducible and low-cost manner. It has shown to link patients with a high intra tumor stromal content and a worse prognosis. Literature shows a wealth of evidence that supports this prognostic value in CRC as well as in other cancers. This PhD research therefore concludes that it should be implemented in the official guidelines of the TNM classification to improve stratification for CRC patients in daily routine pathological evaluation. The prospective, international, multicentre UNITED study will hopefully overcome the last hurdle for this clinical implementation. Lastly, this thesis offers more insight in the elusiveness of the tumor microenvironment and stromatogenesis that contributes to the aggressiveness of some CRC tumors. The biological differences, interconnections and changes in the microenvironment presented give multiple leads for further research and new personalized treatment possibilities. Show less
The surface of eukaryotic cells contains a very dense layer of oligosaccharides called glycans that are linked to protein and lipid carriers and play an important role in cell-cell and cell... Show moreThe surface of eukaryotic cells contains a very dense layer of oligosaccharides called glycans that are linked to protein and lipid carriers and play an important role in cell-cell and cell-extracellular matrix interactions. Cancer-induced changes in glycosylation have an impact on the function of major glycoproteins in the human colon, therefore studies focused on colorectal cancer (CRC)-specific glycosylation signatures can provide novel insights into onset and progression of this disease. The major focus of this thesis was to investigate mucin type O-glycosylation signatures of CRC. For this purpose, a protocol for in-depth analysis of N- and O-glycans obtained from cell lines was developed (Chapter 2) using nanoscale porous graphitized carbon liquid chromatography coupled to mass spectrometry (PGC-nano-LC-MS). In Chapter 3 additional conditions were optimized in the MS methodology by using polar protic dopant (methanol and isopropanol) enriched nitrogen gas to increase sensitivity on the MS and tandem MS level. In Chapter 4 we applied the methodology developed in Chapter 2 to the analysis of O-glycosylation signatures of 26 different CRC cell lines. This analysis resulted in the characterization of more than 150 O-glycan structures and increased our understanding of glycan expression in the analyzed cell lines. To gain further understanding in the mechanisms underlying glycomic changes with colon cell differentiation, we explored changes in the cell line glycome and proteome upon spontaneous and butyrate-stimulated differentiation in in vitro cell culture (Chapter 5). By performing an integrative approach, we generated hypotheses about glycosylation signatures of specific cell adhesion proteins, which may play an important role in cancer progression. The localization of glycans on the cell surface and their role in biological processes are important in cancer pathogenesis, making them potential candidates for glycan targeting immunotherapy. Therefore, we further optimized the methodology to enable comprehensive analysis of N- and O-glycans from specific regions of formalin-fixed, paraffin-embedded tissues using laser capture microdissections and applied it for the analysis of selected regions of CRC tissues and their patient-matched colon mucosa controls (Chapter 6). We identified specific tumor-associated carbohydrate antigens (TACAs) that show expression only in the tumor samples, with no or limited expression in the normal colon mucosa. Since TACAs are present in high abundance on the surface of cancer cells which are linked to many different proteins, these are very promising targets for the development of tumor-specific immunotherapy. Show less
