The aim of the work included in this PhD thesis was to explore the diverse application possibility of using NIR fluorescent probes with specific properties to visualize and characterize cancer and... Show moreThe aim of the work included in this PhD thesis was to explore the diverse application possibility of using NIR fluorescent probes with specific properties to visualize and characterize cancer and cell death. In this thesis, we mainly focus on optical imaging and its application, both at microscopic and macroscopic level. Because we believe optical imaging in particular represents a technology that has unique potential to exploit further our knowledge in preclinical research. First, we imaged breast tumors and their metastases using combinations of four NIR fluorescent probes that possess different optical imaging properties. Then, we studied two different NIR fluorescent probes, PSVue and a heat shock protein-90 alkylator (NIR fluorescent conjugate of GSAO), which can be used to non-invasively imaging cell death with different optical modules in a mouse model of traumatic brain injury. Next, we employed the NIR fluorescently tagged GSAO as a biomarker for monitoring breast cancer cell death after chemotherapy. Moreover, we provides a general discussion about the advantages and the challenging that the state-of-art optical imaging is facing and shares some future prospective. This thesis ends with a summary that outlined the major findings of studies described in different chapters and explored the clinical implications. Show less
Not all hormone receptor positive breast cancer patients benefit from tamoxifen treatment, but may be nonetheless exposed to its side effects (e.g. hot flashes). Tamoxifen needs bioactivation by... Show moreNot all hormone receptor positive breast cancer patients benefit from tamoxifen treatment, but may be nonetheless exposed to its side effects (e.g. hot flashes). Tamoxifen needs bioactivation by formation of the metabolite endoxifen, which is mainly catalyzed by the enzyme CYP2D6. In this thesis, we studied the variation in tamoxifen metabolism in relation to endoxifen serum concentration, tamoxifen efficacy and side effects, focusing on CYP2D6 activity and pharmacogenetics. The importance of good methodology for genotyping and endoxifen measurement was exemplified. In a large trial population, no association between CYP2D6 genotype and disease free survival or the occurence of hot flashes was found, although polymorphisms in the estrogen receptor-1 and UGT2B15 might be related to clinical outcome. Adherence, but not the concomitant use of CYP2D6 inhibiting medication was associated with breast cancer recurrence. CYP2D6 genotype and endoxifen-guided tamoxifen dose escalation led to an increase in endoxifen serum levels and a new 13C-Dextromethorphan breath test was used for phenotyping CYP2D6, which correlated well with CYP2D6 genotype and endoxifen levels. Finally, the CYP2D6 phenotype and endoxifen serum levels are currently prospectively related to breast cancer recurrence. This may lead to therapeutic drug monitoring and selection of patients who benefit most from tamoxifen. Show less
Heijer, M. den; Asperen, C.J. van; Harris, H.; Nippert, I.; Schmidtke, J.; Bouhnik, A.D.; ... ; Tibben, A. 2013
The primary aim of this thesis is to gain insight into which search facilities for spontaneously published stories facilitate breast cancer patients in finding stories by other patients in a... Show moreThe primary aim of this thesis is to gain insight into which search facilities for spontaneously published stories facilitate breast cancer patients in finding stories by other patients in a similar situation. According to the narrative approach, social comparison theory, and social cognitive theory, reading stories about similar others may have the most positive impact. The research followed a user-centred design: users of search facilities (i.e., patients who want to read stories written by others) were involved in every phase of the research so that the search facilities could be tailored to these users__ needs and preferences instead of forcing users to change their search behaviour to conform to search facilities that were developed without their involvement. We examined which breast cancer patients spontaneously publish their story online and which themes they write about in their stories, and how these stories are presented and disclosed on websites. We then examined which topics and writer characteristics patients prefer to search for and translated these preferences into search facilities. Finally, we examined which search facilities show the most positive effects on patient satisfaction and search success, and how patients actually search for stories written by others. The research was conducted from a clinical informatics perspective, using knowledge from the fields of information retrieval, human-computer interaction and psychology. Show less
Hezewijk, M. van; Bastiaannet, E.; Putter, H.; Scholten, A.N.; Liefers, G.J.; Rea, D.; ... ; Velde, C.J.H. van de 2013
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
TGF-beta and BMPs are members of the TGF-beta superfamily of cytokines which play an important role in a multitude of processes. In cancer, TGF-beta is known for its dual role: in early stages it... Show moreTGF-beta and BMPs are members of the TGF-beta superfamily of cytokines which play an important role in a multitude of processes. In cancer, TGF-beta is known for its dual role: in early stages it inhibits cancer cell proliferation, whereas in later stages it promotes invasion and metastasis. In this thesis, a 3 dimenstional model to monitor TGF-beta-induced invasion of breast cancer cells is presented and an important role for MMP2 and MMP9. Furthermore, BMP-7 could inhibit TGF-beta-induced invasion through inhibition of TGF-beta-induced integrin beta3 expression. The property of TGF-beta to induce epithelial to mesenchymal transition (EMT) is thought to contribute to its pro-invasive effect. We found that transcription factors involved in this process induce invasion. Lastly, we identified kinases involved in BMP signaling. These findings help the understanding of breast cancer cell invasion and a way to prevent this process. Show less
