Cancer immunotherapy has experienced remarkable advances in the last decades. Striking clinical responses have been achieved for several solid cancers, particularly cancer types with a high... Show moreCancer immunotherapy has experienced remarkable advances in the last decades. Striking clinical responses have been achieved for several solid cancers, particularly cancer types with a high mutation burden, which placed tumour-mutated antigens (neoantigens) centre stage as targets of tumour immunity and cancer immunotherapy. Neoantigens can be presented in complex with HLA molecules on the tumour cell surface, where T cells with the correct specificity can recognize the neoantigen as ‘non-self’ which will trigger killing of the tumour cell by the T cell. In theory, cancers with a low/moderate mutation burden that present neoantigens in complex with HLA class molecules could still be eligible for T cell-mediated immunotherapy. This thesis, describes the finding that neoantigen-specific T cells are present in mismatch-repair proficient (MMR-p) colorectal cancer patients, a low mutation burden cancer type. Moreover, CD39 and CD103 were found as cell surface markers that pinpoint the T cell population that contains the neoantigen-specific T cells. In addition, subsequent metastasis of a melanoma patient cohort were studied and revealed that also at advanced, late-stage disease, neoantigen-directed T cell therapy is, in theory, still applicable. Taken together, the studies reveal potential for the development of neoantigen-directed cancer immunotherapy for a broader patient population. Show less
To generate a successful novel therapy, a deep understanding of oncogenesis in combination with mechanistic understanding of anti-cancer compounds are needed. The work described in this thesis aims... Show moreTo generate a successful novel therapy, a deep understanding of oncogenesis in combination with mechanistic understanding of anti-cancer compounds are needed. The work described in this thesis aims to contribute to the knowledge on SUMO regulated oncogenesis, understanding the consequences of abolishment of SUMO signaling and exploiting the potential of SUMO E1 inhibitors. To this end, we describe SUMO as a potential biomarker for cancer aggressiveness and increase our understanding on SUMO’s role in cell cycle progression. We exploited the potential of SUMO E1 inhibition by combining with hypomethylating compound 5-Aza-2’ deoxycytidine, leading to increased cytostatic efficacy. Furthermore, we repurposed the SUMO E1 inhibitor TAK981 and hypomethylating drug 5-Aza-2’ deoxycytidine to improve engineered TCR (eTCR) T cell therapy and broaden our understanding of its immunomodulatory potential. Show less
This thesis aims to improve patient outcomes after major oncological gastrointestinal surgery, by identifying targets for optimizing perioperative care. On the one hand, identifying (adjustable)... Show moreThis thesis aims to improve patient outcomes after major oncological gastrointestinal surgery, by identifying targets for optimizing perioperative care. On the one hand, identifying (adjustable) prognostic factors for postoperative complications and then using them in prediction models, and gaining insight into the quality of life after surgery. Improving preoperative risk assessment and subsequent personalization of postoperative care can reduce the rate of postoperative complications and mortality. In addition, risk prediction can support clinical knowledge in making treatment decisions. Modifiable prognostic factors are particularly important to identify as they may be optimized prior to surgery. Modifiable prognostic factors can then be used in prehabilitation programs to improve a patient's physical condition and thus improve patient outcomes. In addition, information about treatment consequences and treatment-related health problems is important for treatment decision-making for patients and healthcare professionals. Especially, if several treatment options are available, knowledge about (long-term) consequences of the treatment options is important for shared decision-making. This knowledge can also contribute to optimizing postoperative care and rehabilitation programs. In conclusion, the leads described in this thesis for improving postoperative care can be used to improve short- and long-term patient outcomes after complex oncological gastrointestinal surgery. Show less
The use of existing medications for diseases they were not originally developed for is called drug repositioning. A popular drug repositioning method to find new drugs against specific cancer types... Show moreThe use of existing medications for diseases they were not originally developed for is called drug repositioning. A popular drug repositioning method to find new drugs against specific cancer types is to search for drugs which are expected to bring back the gene expression activity of cancer cells to that of healthy cells (‘normalization’). One of the main research goals of this thesis was to investigate of this method could also be used on the gene expression profiles of individual tumors, enabling personalization of drug repositioning candidates for each patient. We initially had some success with this approach but this eventually lead to a systematic validation of the underlying principle using almost 10,000 tumor samples across 18 different tumor types. Unfortunately, the predictive power of the method was found to be much lower than previously reported and the part that remained could be nullified by correcting the gene expression profiles of the drugs for the downstream effects of reduced cell division. These results indicate that the current use of the method does not result in drug repositioning candidates specific for a tumor type but is only able to select generally cell-toxic drugs. Show less
Type I interferons (IFN-I) are pleiotropic cytokines that were originally identified for their antiviral properties and are now recognized for playing key roles in the defense against a range of... Show moreType I interferons (IFN-I) are pleiotropic cytokines that were originally identified for their antiviral properties and are now recognized for playing key roles in the defense against a range of other microorganisms as well as cancer. Their production should be well-controlled to be of benefit to the host, as excessive or chronic IFN-I expression leads to adverse effects such as immunosuppression or the induction of severe immunopathology.The studies presented in this thesis are aimed at uncovering mechanisms that regulate the production of IFN-I. The obtained knowledge on the involved molecular processes, may aid the development of targeted therapies that enhance or intercept IFN-I responses for maximum host protection while minimizing damage. Show less
Immune checkpoint therapies that aim to (re)activate the immune response against cancer cells have shown promising results in a variety of tumor types. Yet, a large fraction of cancer patients does... Show moreImmune checkpoint therapies that aim to (re)activate the immune response against cancer cells have shown promising results in a variety of tumor types. Yet, a large fraction of cancer patients does not benefit from these therapies. While the presence of a substantial number of immune cells, and in particular T cells, in the tumor is generally related with a better clinical response to checkpoint therapies, the T cells in the tumor are diverse in their capacity to eliminate the tumor. In order to improve treatment outcome of cancer patients, we require a better understanding of the roles of different T cells in the response (and resistance) to immune checkpoint therapy. The development of single cell profiling technologies has provided us with a powerful tool to analyze the state and functionality of individual cells. In this thesis, I have used single cell profiling methods in combination with innovative experimental technologies to unravel the diversity of T cells in human tumors and define the changes in the profiles of T cells that occur in response to treatment with immune checkpoint therapy to dissect which T cells are important for therapy response. Show less
All cellular organisms contain genomic DNA which provides the instructions for their correct development and functioning. Damage to this DNA may interfere with critical cellular processes such as... Show moreAll cellular organisms contain genomic DNA which provides the instructions for their correct development and functioning. Damage to this DNA may interfere with critical cellular processes such as transcription and replication and has the potential to drive mutagenesis. In turn, this may underlie inherited disorders and accelerate progression of diseases such as cancer and neurodegenerative disorders. The protection of cells and organisms against these devastating effects of DNA damage relies on the DNA damage response (DDR), which comprises a complex network of signaling and repair pathways that coordinate the sensing, signaling and repair of DNA lesions while accommodating suitable adjustments in for instance chromatin structure and cell cycle progression. Not only does the DDR dictate the appropriate repair pathway for several types of DNA damage, including DNA double-strand breaks (DSB), it also modulates replication fork surveillance mechanisms in response to DNA replication stress (RS). While many core proteins have been studied in detail, the full repertoire of factors involved in these pathways remains unknown. Clearly, extending our knowledge on regulators of the DDR will contribute to our understanding of the development, and possibly the treatment, of the numerous disorders that are associated with defects in the DDR. The research described in this thesis has successfully identified and characterized novel factors in DSB repair and the RS response. Show less
T cell exhaustion is a state of T cell hypofunction arising during persistent viral infections and cancer. Recent advances in the field of immunology uncover the roles of cytokines in regulating T... Show moreT cell exhaustion is a state of T cell hypofunction arising during persistent viral infections and cancer. Recent advances in the field of immunology uncover the roles of cytokines in regulating T cell responses. Using LCMV Clone-13 as a model of persistent viral infection, this thesis investigates the roles of IL-27 and IFN-I in regulating T cells during infection. In addition, the thesis explores the potential of JAK inhibitor in rescuing T cell exhaustion during persistent viral infection and cancer. Show less
Het onderzoek beschreven in dit proefschrift is gericht op de identificatie en karakterisering van regulatoren en/of effectoren van TGF-β-signalering en TGF-β-geïnduceerde EMT in pancreas-, long-... Show moreHet onderzoek beschreven in dit proefschrift is gericht op de identificatie en karakterisering van regulatoren en/of effectoren van TGF-β-signalering en TGF-β-geïnduceerde EMT in pancreas-, long- en borstkankertypes. Deze nieuw geïdentificeerde componenten en mechanismen kunnen worden onderzocht voor de ontwikkeling van geneesmiddelen voor kankertherapie. Show less
Despite the interest and success in immunotherapy, our current understanding of how the immune activation balance – on the macro level – and the expression of receptors and their ligands – on the... Show moreDespite the interest and success in immunotherapy, our current understanding of how the immune activation balance – on the macro level – and the expression of receptors and their ligands – on the micro level – shape health and disease is still limited. By identifying novel regulatory networks that dictate immune cell activity in physiologically relevant settings, well-designed pooled genetic screens could offer a relevant approach to address this knowledge gap. Genetic screens have become a powerful tool to identifygenes that affect the response and phenotype of a cell in an unbiased manner.In this thesis, I aimed to identify regulators of immune cell activation in the context of cancer through a combination of in vitro and in vivo genetic screens and genetically modified mouse models. Specifically, this was achieved by both 1) using genetic screening technologies to identify novel cancer cell-expressed inhibitory ligands or regulatorsof immune-modulating ligands in an unbiased manner, and 2) investigating the effect of these regulators on the cellular components and signaling pathways that constitute the local tumor microenvironment and potentially dictate anti-tumor efficacy. Show less
Being confronted with cancer is a life-changing event, with major impact to well-being, quality of life and relationships. Cancer treatments and outcomes have improved, but possess the potential to... Show moreBeing confronted with cancer is a life-changing event, with major impact to well-being, quality of life and relationships. Cancer treatments and outcomes have improved, but possess the potential to impair reproductive and sexual function. International guidelines highlight the importance of timely discussion of sexual function and fertility deterioration resulting from treatments. In spite of these developments, practice behaviour and attitudes of health professionals have been reported to vary.The first part of this thesis demonstrates barriers among oncology professionals in the Netherlands in discussing sexual function during daily practice. In general, consensus exists regarding responsibility for addressing sexual dysfunction. Despite, the implementation of discussing sexual function as a standard of care is not carried out structural.Part two describes practice routines concerning the counselling on impaired fertility and fertility preservation for cancer patients of reproductive age. Medical oncologists and oncology nurses both reported discussing the impact of treatment on fertility. However, it was not performed in all cases and depending on factors like educational level, experience, type of hospital, prognosis and chances of fertility recovery.Furthermore, testicular cancer patients were evaluated on specific items concerning the discussion, referral and process of semen cryopreservation. Long term reproductive concerns were identified among survivors. Show less
This thesis aims to gain a better understanding of NER, to elucidate new molecular mechanisms and proteins that orchestrate how DNA repair is carried out on genomic DNA that is tightly packed in... Show moreThis thesis aims to gain a better understanding of NER, to elucidate new molecular mechanisms and proteins that orchestrate how DNA repair is carried out on genomic DNA that is tightly packed in chromatin inside the living cell. It is important to obtain a better clinical picture of how inherited defects in DNA repair genes shapes phenotypes in patients with DNA repair-deficiency disorders. Show less
Tumor heterogeneity favors tumor tissue to survive and resist drugs, leading to the failure of chemotherapeutic agents to induce a therapeutic response. In addition, the absorption mechanisms,... Show moreTumor heterogeneity favors tumor tissue to survive and resist drugs, leading to the failure of chemotherapeutic agents to induce a therapeutic response. In addition, the absorption mechanisms, metabolism and excretion of chemotherapeutic drugs, which are commonly used for cancer patients and the lack of specific targeting of these drugs can cause adverse effects on treated patients. Thus, the general objective of this thesis is to investigate the biological activity of targeted poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) as a drug delivery system (DDS) for carvedilol (CVDL) or oxaliplatin (OXA), in vitro and in vivo, to treat colorectal cancer (CRC). DDSs were formulated to achieve this goal. In chapters 2, 3 and 4, our studies were discussed in detail on the formulations and characterizations of NPs as DDSs with ideal characteristics to increase the therapeutic range of drugs at the tumor site. As well as the biological evaluation of these DDS when its anti-inflammatory activity (Chapter 2) and its antitumor activity in vitro (Chapters 2, 3 and 4) and in vivo (Chapters 3 and 4). Taken together, all the DDSs studied in this thesis were able to improve the chemotherapeutic efficiency of the drugs studied in Chapters 2, 3 and 4. Show less
Upon infection or vaccination, naïve CD8+ T cells clonally expand and differentiate into antigen-specific effector cell populations, which turn into phenotypically diverse memory CD8+ T cell... Show moreUpon infection or vaccination, naïve CD8+ T cells clonally expand and differentiate into antigen-specific effector cell populations, which turn into phenotypically diverse memory CD8+ T cell subsets that differ in their cytokine polyfunctionality, cytolytic capacity and homing properties. The circulating memory CD8+ T cell pool can be largely classified in two major subsets: effector memory T (TEM) and central memory T (TCM) cells. Contrary to the classical view that lymphocytes continuously recirculate, tissue-resident memory T (TRM) cells have been discovered as cells with the unique ability to reside in tissues with limited recirculation through the blood. Antigen-specific CD8+ TRM cells are induced upon antigen encounter and localize to many different tissues, including barrier tissues, where they play a crucial role in protection against infectious and malignant disease. Within these major circulating and resident T cell subsets a variety of phenotypes and functions exists. However, the development of the heterogeneous populations of memory T cells is not fully understood. In this thesis we dissect the development and heterogeneity of antigen-specific circulating and tissue-resident CD8+ T cells upon vaccination and infection, study their protective capacity in infectious and malignant disease and use this information to improve vaccination and immunotherapeutic strategies. Show less
Biomarker molecules are analyzed in clinical tests to diagnose a disease, but often these test lack sensitivity or specificity. Also, for many diseases there is not even a blood based test... Show moreBiomarker molecules are analyzed in clinical tests to diagnose a disease, but often these test lack sensitivity or specificity. Also, for many diseases there is not even a blood based test available, while blood collection is relatively low invasive. For breast- and pancreatic cancer, there are several proteins that could potentially serve as biomarkers in blood, but these are not yet specific enough to use for diagnostic testing. Further research on other types of biomarkers may therefore be a valuable addition to eventually be able to develop a blood test. Methods for glycosylation profiling from serum and dried bloodspots with mass spectrometry were developed and applied to pancreatic- and breast cancer biomarker studies. Differences were found between profiles of healthy and sick persons for pancreatic cancer, but no clear differences were seen for breast cancer. This is probably due to the many different forms of breast cancer which result in different profiles. In the future, combining different types of markers from serum might ensure that differences between healthy and sick, between different diseases and between types of disease can be identified. This could lead to the development of a blood test for the early detection of cancer and other diseases. Show less
As HLA Class I expression is an important target for cytotoxic T cells but an in inhibitor of NKcells, we were interested in the regulation of its expression.We review HLA expression in UM, how it... Show moreAs HLA Class I expression is an important target for cytotoxic T cells but an in inhibitor of NKcells, we were interested in the regulation of its expression.We review HLA expression in UM, how it is involved in the inflammatory phenotype, how it is regulated and how putative treatments might be effective in its expression.We investigate the potential role of the NFkB pathway in the regulation of inflammation in UM and its potential association with HLA Class I expression.In order to increase our understanding for the reason behind the elevated HLA Class I expression in UM tumours, we investigate the involvement of epigenetics. We focus on a set of epigenetic enzymes called histone deacetylases and report that these regulators are highly expressed in Monosomy 3 UM.We wonder whether HDAC expression is influenced by the presence of infiltrating lymphocytes and macrophages.We focus on miRNA’s as another set of epigenetic regulators of inflammation. We investigate the potential relation of a set of 125 miRNA’s with HLA Class I expression and the presence of an infiltrate in UM and report two patterns of miRNA expression.We study the LAG3 immune checkpoint in UM tumours. As immune checkpoints might be responsible for the T cell exhaustion which is observed in UM, we investigate the involvement of LAG in prognostication and study how LAG3 and its ligands are distributed among different UM tumours. Show less
Immunotherapy approach to cancer is only benefiting to a minority of patients. In this study, we approach cancer solutions by studying the microenvironment and its immunological signature... Show moreImmunotherapy approach to cancer is only benefiting to a minority of patients. In this study, we approach cancer solutions by studying the microenvironment and its immunological signature throughout the body by focusing on the systemic immunity with new technology like mass cytometry. By highlighting specific immunological patterns in cancer, we were able to associate responsive immune cells and positive outcome, therefore paving the way to improve immunotherapy in cancer. Show less
Since cancer survival rates are rising, there is growing attention for longterm side effects of cancer and its treatment. A common side effect is the negative impact of treatment on sexuality of... Show moreSince cancer survival rates are rising, there is growing attention for longterm side effects of cancer and its treatment. A common side effect is the negative impact of treatment on sexuality of patients and their partners. Patient and partners as well as healthcare professionals experience several barriers to discuss this topic, like lack of time and lack of knowlegde. Two-thirds of the cancer patients reported to be in need of information regarding sexual health; especially those who were younger, who reported a negative impact of cancer on sexuality and those who were diagnosed less than two years ago. Patients and partners reported to prefer to discuss sexual health with nurse practitioners throughout the treatment proces. Besides, satisfaction with sexual life after treatment is related to satisfaction before treatment, not only with current sexual function.Widely available information and defining responsibility within the oncology treatment team would be helpful to improve communication around sexual health in cancer care. Additionally, specialized clinics would tackle soms frequently reported barriers of discussing sexuality. More reseach is needed on the implementation of sexual healthcare in oncology practice to deliver continuum of care, which will ultimately improve patient care. Show less
The aim of this thesis was to better understand the underlying biology of tumor-immune interactions, especially in the circulation of CRC patients. The focus was primarily on the innate immune... Show moreThe aim of this thesis was to better understand the underlying biology of tumor-immune interactions, especially in the circulation of CRC patients. The focus was primarily on the innate immune system including NK cells, NKT cells, and macrophages. Show less
MHC class I antigen-presentation plays a pivotal role in anti-tumor immunity. High surface expression of MHC-I molecules is generally correlated with high CD8 T cell infiltrate and improved overall... Show moreMHC class I antigen-presentation plays a pivotal role in anti-tumor immunity. High surface expression of MHC-I molecules is generally correlated with high CD8 T cell infiltrate and improved overall survival in many cancers. In contrast, partial or complete loss of MHC-I surface expression is associated with reduced survival and primary-resistance to immunotherapy in cancers. Expression of additional molecules in the tumor microenvironment (TME), such as PD-L1 and HLA-E, further shape immune responses. The presence of immune cells and the expression of immune-related genes together determine the ‘immune landscape’ of cancers, while the local production of interferons strongly impacts this environment. Although MHC-I and PD-L1 are both regulated by the IFN pathway, an in-depth study on immune escape of NSCLC showed that the expression of co-inhibitory markers and the loss of MHC-I expression are two independent mechanisms of immune evasion. This classifies tumors into different “types” depending on their MHC-I and PD-L1 expression. The differential expression of MHC-I and PD-L1 suggests that immune-escape of cancer cells occurs through a multitude of distinct “hard-wired” and “soft-wired” modifications and knowing which of the mechanisms underlie immune escape determines which immunotherapeutic strategy has the most potential for clinical success. Show less
