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
One of the challenges of nanotechnology is to improve the efficacy of treatments for diseases, in order to reduce morbidity and mortality rates. Following this line of study, we made a nanoparticle... Show moreOne of the challenges of nanotechnology is to improve the efficacy of treatments for diseases, in order to reduce morbidity and mortality rates. Following this line of study, we made a nanoparticle formulation with a small size, uniform surfaces, and a satisfactory encapsulation coefficient as a target for colorectal cancer cells. The results of binding and uptake prove that using the target system with folic acid works: Using this system, cytotoxicity and cell death are increased when compared to using free oxaliplatin. The data show that the system maximized the efficiency of oxaliplatin in modulating tumor progression, increasing apoptosis and decreasing resistance to the drug. Thus, for the first time, our findings suggest that PLGA-PEG-FA increases the antitumor effectiveness of oxaliplatin by functioning as a facilitator of drug delivery in colorectal cancer. Show less
Chondrosarcoma is the second most common primary bone malignancy, representing one fourth of all primary bone sarcomas. It is typically resistant to radiation and chemotherapy treatments. However,... Show moreChondrosarcoma is the second most common primary bone malignancy, representing one fourth of all primary bone sarcomas. It is typically resistant to radiation and chemotherapy treatments. However, the molecular mechanisms that contribute to cancer aggressiveness in chondrosarcomas remain poorly characterized. Here, we studied the role of mitochondrial transporters in chondrosarcoma aggressiveness including chemotherapy resistance. Histological grade along with stage are the most important prognostic biomarkers in chondrosarcoma. We found that high-grade human chondrosarcoma tumors have higher expression of the mitochondrial protein, translocase of the outer mitochondrial membrane complex subunit 20 (TOMM20), compared to low-grade tumors. TOMM20 overexpression in human chondrosarcoma cells induces chondrosarcoma tumor growth in vivo. TOMM20 drives proliferation, resistance to apoptosis and chemotherapy resistance. Also, TOMM20 induces markers of epithelial to mesenchymal transition (EMT) and metabolic reprogramming in these mesenchymal tumors. In conclusion, TOMM20 drives chondrosarcoma aggressiveness and resistance to chemotherapy. Show less
Y Cutaneous T-cell lymphomas and leukemias (CTCLs) are a heterogeneous group of extranodal non-Hodgkin's lymphomas. These are characterized by an accumulation of malignant CD4(+) T-lymphocytes in... Show moreY Cutaneous T-cell lymphomas and leukemias (CTCLs) are a heterogeneous group of extranodal non-Hodgkin's lymphomas. These are characterized by an accumulation of malignant CD4(+) T-lymphocytes in the skin, lymph nodes, and peripheral blood. Novel treatment options are needed for patients who progress to advanced stage disease. Cucurbitacin I has previously shown promising results in Sezary syndrome (Sz). A plethora of cucurbitacins, however, have not yet been tested in CTCL. Herein, we investigated the effect of cucurbitacin E and I in two CTCL cell lines. We show that both cucurbitacins decrease viability and cause apoptosis in these cell lines, although HuT-78 was more affected than SeAx (IC50 of 17.38 versus 22.01 mu M for cucurbitacin E and 13.36 versus 24.47 mu M for cucurbitacin I). Moreover, both cucurbitacins decrease viability of primary cells of a Sz patient (56.46% for cucurbitacin E and 59.07% for cucurbitacin I). Furthermore, while JAK2 inhibition leads to decreased viability in SeAx cells (IC50 of 9.98 and 29.15 mu M for AZD1480 and ruxolitinib respectively), both JAK1 and JAK3 do not. This suggests that JAK2 has a preferential role in promoting survival. Western blotting in SeAx cells revealed that both cucurbitacins inhibit STAT3 activation (P < 0.0001), while only cucurbitacin I inhibits STAT5 activation (P = 0.05). This suggests that STAT3 plays a preferential role in the mechanism of action of these cucurbitacins. Nevertheless, a role of STAT5 and JAK2 cannot be excluded and should be explored further. This knowledge could contribute to the development of effective therapies for CTCL and other malignancies involving dysfunction of the JAK/STAT pathway. Show less
Yang, J.X.; Snijders, M.L.H.; Haasnoot, G.W.; Kooten, C. van; Mallat, M.; Fijter, J.W. de; ... ; Eikmans, M. 2018
Many of the recognition molecules and mechanisms involved in immune responses have no bias towards external stimuli, but also sense and respond to pathological and physiological changes of non... Show moreMany of the recognition molecules and mechanisms involved in immune responses have no bias towards external stimuli, but also sense and respond to pathological and physiological changes of non infectious origin taking place within the body. Aiming at defining potential immuno-therapeutic strategies to treat human atherosclerosis, the focus of this work was the modulation of immune processes determinant of atherosclerosis lesion progression or cessation in mice, such as hematopoiesis, diapedesis and intravasation, leukocyte differentiation, cholesterol uptake apoptosis and cell survival. Modulation of these processes, by using bone marrow transplantation of hematopoietic stem cells with genetic deficiencies or over-expressing human or mouse engineered genes, demonstrated to alter the fate of atherosclerotic lesions at the balance between macrophage accumulation and lesion vulnerability versus resolution of inflammation and wound healing. This thesis demonstrates that processes responsible for the development and progression of atherosclerosis are dynamic and can be modulated to induce lesion stabilization and disease resolution. These results are promising for the development of novel therapeutics and challenge the current notion that atherosclerosis has a predetermined fate towards lesion vulnerability to rupture, which in humans results in thrombosis and clinical manifestations such myocardial infarction or stroke and sudden death. Show less
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
Immunotherapy and chemotherapy are major strategies in current cancer treatments. In the first half of this thesis, a new way of antigen cross-presentation from apoptotic cells to APCs, mediated by... Show moreImmunotherapy and chemotherapy are major strategies in current cancer treatments. In the first half of this thesis, a new way of antigen cross-presentation from apoptotic cells to APCs, mediated by gap junctions, is described. And potential anti-tumor applications of gap junction mediated antigen cross-presentation are discussed in the context of the current knowledge. In the second half of this thesis, an unexpected novel mechanism of action__selective induction of histone eviction__is described, which could explain the long standing clinical observation that anthracycline members, like doxorubicin, daunorubicin and aclarubicin, are efficient but with long term side-effects such as cardiotoxicity Show less
There is an urgent need for a better and more effective therapy for neuroblastoma, a pediatric tumor of the sympathetic nervous system. Despite intensive treatment, less than 50 % of the patients... Show moreThere is an urgent need for a better and more effective therapy for neuroblastoma, a pediatric tumor of the sympathetic nervous system. Despite intensive treatment, less than 50 % of the patients with high-risk neuroblastoma survive. Therefore we have investigated if doublecortin-like kinase is a potential therapeutic target for neuroblastoma. Doublecortin-like kinase (DCLK1) gene encodes doublecortin-like (DCL) and DCLK-long that are crucial for correct proliferation and differentiation of neuroblasts. We found that these proteins are overexpressed in human neuroblastomas and gliomas but not in other tumors or normal tissue. DCL/DCLK-long knockdown in mouse and human neuroblastoma cells resulted in apoptotic cell death. We also found that DCL is involved in the control of mitochondrial activity, energy production and neuroblastoma cell proliferation. In vivo, we observed delayed tumor growth in neuroblastoma tumor xenografts with inducible DCL knockdown. Moreover, we showed that combining DCL/DCLK-long knockdown with low doses of vinca alkaloids results in a synergistic apoptotic effect, confirming that this is a potential approach to consider for neuroblastoma therapy. In conclusion, the data presented in this thesis provide new insights in the biological function of the DCLK1 gene and indicate that DCL and DCLK-long are potential therapeutic targets for neuroblastoma. Show less
With the ever-increasing life expectancies of people, the prevalence of aging-related diseases is also increasing. We studied a unique cohort of people; offspring of nonagenarian siblings with the... Show moreWith the ever-increasing life expectancies of people, the prevalence of aging-related diseases is also increasing. We studied a unique cohort of people; offspring of nonagenarian siblings with the propensity for longevity were also recruited and compared to their partners, representing the general population. The offspring (~60 year old) already show lower prevalence of cardiovascular disease and diabetes. In the thesis __Cellular stress in vitro and longevity on vivo__ it is reported how cells (dermal fibroblasts) derived from these offspring were compared with cells from their partners. It was shown that they react differenly in vitro under both non stressed and under conditions of oxidative stress. Future research is warranted to further elucidate the genes involved in these differences. Show less
Cells in the human body have to deal with DNA damage daily, either caused by external or internal sources. The DDR is particularly strong in stem cells. Since these cells have a long life span and... Show moreCells in the human body have to deal with DNA damage daily, either caused by external or internal sources. The DDR is particularly strong in stem cells. Since these cells have a long life span and are essential for tissue homeostasis, tolerance to damaged DNA would lead to accumulation of mutations and malignant transformation. In addition, accumulation of damaged DNA would lead to loss of the stem cell pool and contribute to aging. In this thesis I investigated the role of the DNA damage response in the context of stem cells as well as cancer cells, from the response to different DNA damaging agents, to the importance of the interaction with the extracellular matrix in combination with the presence of oncogenes. In order to acquire a complete picture of the DNA damage response in mES cells, and therefore elucidate novel pathways involved in this particular response, we combined OMICS techniques such as Functional Genomics, Transcriptomics and Phosphoprotoemics, that once overlapped, allowed us to find novel pathways that where not previously described to be involved in the DNA damage response. Show less
Hoogerwerf, J.J.; Zoelen, M.A. van; Wiersinga, W.J.; Veer, C. van 't; Vos, A.F. de; Boer, A. de; ... ; Poll, T. van der 2010
