Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 98-130) Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 117-130).

Thesis (Ph. D.)--University of Texas at Austin, 2009. / Title from PDF title page (University of Texas Digital Repository, viewed on Sept. 17, 2009). Vita. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 228-268).

Accompanying CD-ROM contains image files and software. Bibliography: leaves 259-286. Explores the factors affecting the movement of tumour cells from a primary malignancy across the peritoneal cavity to the port-site following laparoscopic intervention. Filter methods and radio-labelled tumour cells provided the most useful way of following cell movement. Concludes spread of tumour cells to the port-site is more likely in the presence of disseminated disease, as well as with inappropriate surgical technique. Metastasis may be reduced by the use of intraperitoneal lavage and appropriate surgical technique.

Orientador: Edgard Graner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T01:25:31Z (GMT). No. of bitstreams: 1 Bastos_DeboraCampanella_M.pdf: 5817801 bytes, checksum: cdb6cd787fadb415e31229779a0f07d9 (MD5) Previous issue date: 2009 / Resumo: A enzima ácido graxo sintase (FASN) é responsável pela síntese endógena de ácidos graxos, e tem alta expressão em diversas neoplasias malignas, pois sua atividade parece ser necessária para a síntese dos fosfolipídios de membrana das células tumorais. A droga orlistat (Xenical®), usada para tratamento de obesidade, foi recentemente descrita como tendo propriedades anti-neoplásicas em câncer de próstata, mama e melanoma devido à sua capacidade de bloquear especificamente a atividade de FASN. O tratamento de células endoteliais com orlistat bloqueia a síntese de ácidos graxos e inibe a proliferação e a neovascularização em ensaio ex vivo, o que sugere um papel antiangiogênico. O sistema linfático é o componente da circulação responsável pela drenagem do fluido intersticial e é essencial no funcionamento do sistema imunológico além disso os vasos linfáticos são também a via primária de metástase de várias neoplasias malignas, dentre elas o melanoma, neoplasia maligna originada nos melanócitos da pele ou mucosas que apresenta alto índice de metástases e é resistente à quimioterapia. A linfangiogênese (formação de novos vasos linfáticos) é iniciada pela liberação de fatores de crescimento que induzem a proliferação e aumento de permeabilidade das células endoteliais linfáticas. Os fatores de crescimento VEGF-C e VEGF-D e seus receptores VEGFR-2 e VEGFR-3 estão relacionados com a progressão tumoral. Existe uma correlação positiva entre a linfangiogênese e a presença de metástase em linfonodos sentinela e uma correlação inversa com a sobrevida livre de doença, o que indica que vasos linfáticos representam um alvo para avaliação do prognóstico ou terapia contra metástases. Em trabalho recente realizado por nosso grupo, foi demonstrado que o tratamento de camundongos portadores de melanomas intraperitoneais causados pela injeção de células B16-F10 com orlistat reduziu em 50% o número de metástases para linfonodos mediastínicos. Como não há informação na literatura sobre a relação de FASN e linfangiogênese, nosso trabalho teve comoobjetivo principal estudar o efeito da inibição da enzima FASN na neoformação linfática em modelos experimentais, através da injeção de células de melanoma murino B16-F10 nas orelhas de camundongos C57Bl6 e indução de reação inflamatória através de feridas circulares nas orelhas de camundongos Balb-C. Por meio de microlinfangiografia fluorescente, técnica que permite a visualização de vasos linfáticos através da injeção intradérmica de uma solução de dextrano a 1% marcado com FITC e avaliação da rede linfática no programa Scion Image, foi observado que a densidade de vasos linfáticos nas orelhas dos camundongos Balb-C e C57Bl6 tratados com orlistat aumentou em relação ao grupo controle. Em resumo nossos resultados mostram que a inibição de FASN com orlistat aumenta a extensão, ramificação e/ou permeabilidade dos linfáticos em região peritumoral (ou ao redor de feridas cirúrgicas). / Abstract: Fatty acid synthase (FASN) is the metabolic enzyme responsible for the endogenous biosynthesis of fatty acids. FASN is overexpressed in several malignant neoplasms and its activity seems to be necessary for the synthesis of membrane phospholipids in the tumor cells. The drug orlistat (Xenical ®), which is clinically used for the treatment of obesity, have shown anti-cancer properties in prostate and breast cancer and melanoma due to its ability to specifically block FASN activity. It was recently demonstrated that treatment of endothelial cells with orlistat blocks the synthesis of fatty acids and inhibits the proliferation and neovascularization. The lymphatic system is the component of the blood circulation responsible for the drainage of interstitial fluid, what is essential to the function of the immune system. Lymphatic vessels are also the primary route of metastasis in several malignancies such as melanoma, wich is originated in the skin or mucous membranes and shows high rates of metastasis and resistency to chemotherapy. Lymphangiogenesis is initiated by the release of growth factors that induce the proliferation and increased permeability of lymphatic endothelial cells. The growth factors VEGF-C and VEGF-D and their receptors VEGFR-2 and VEGFR-3 have been related with tumor progression. There is a positive correlation between lymphangiogenesis and the presence of metastasis in sentinel lymph nodes. An inverse correlation between lymphangiogenesis and disease-free survival has also been described, suggesting that lymphatic vessels could be a target against metastasis. We have shown, in a recent study done by our group, that the orlistat treatment was able to reduced by 50% the number of experimental melanoma metastasis to mediastinal lymph nodes. Since there is no information in the literature about the effect of FASN inhibition on lymphangiogenesis, the purpose of this work was to study the consequences of the orlistat treatment in lymphatic neoformation by using two experimental models. In the first, B16-F10 murine melanoma cells were injected in the ears of C57Bl6 mice in order to inducelynphangiogenesis around the tumors. In the second model, circular wounds were done in the ears of Balb-C mice to induce a local inflammatory reaction and lymphangiogenesis. Lymphatics vessels were observed with the aid of fluorescent microlymphangiography, that allows the observation of the lymphatic vessels by intradermal injection of a solution of 1% of FITC- conjugated dextran. The extension of the lymphatic network was determined by using the Scion Image software. The density of lymphatic vessels significantly increased in both Balb-C and C57Bl6 mice treated with orlistat in comparison to the controls. Moreover, the size of the primary tumors and metastastic lymph nodes were measured and their volumes calculated. In summary, our results show that the inhibition of FASN with orlistat increases the extension, branching and/or permeability of the lymphatics vessels in the peritumoral region and around surgical wounds. / Mestrado / Patologia / Mestre em Estomatopatologia

Breast cancer has a high propensity to metastasize to bone. While the genetic and epigenetic changes associated with metastatic breast cancer progression are being identified, the changes that drive metastatic progression are poorly understood. Proteases, and in particular matrix metalloproteinases (MMPs), have been shown to play a pivotal role in certain aspects of tumor metastasis by modifying the affected microenvironment. Bone matrix-depositing mouse MC3T3 osteoblasts were co-cultured with metastatic human MDA-MB-23 1 (MDA23 1) cells or the bone-homing MDA-MB 231-1 833/TR (1 833/TR) variant in an effort to identify novel, osteoclast-independent, changes to the tumor/bone microenvironment. Co-culture-induced changes in the complete “protease and inhibitor” expression profile in the osteoblasts and the tumor cells were then determined using targeted murine and human specific microarray chips (CLIP-CHIP TM ). This analysis revealed an increase in the RNA expression of collagenase-3 (MMP 13) in the co-cultured osteoblasts that was confirmed by qPCR. Further, Western blotting indicated increased MIvIP13 protein secretion into the bone matrixltumor microenvironment by the co-cultured MC3T3 cells. The elevation in osteoblast-produced MMP13 was observed when the co- cultured tumor cells were in direct contact or separated by filters. Additionally, the elevation was also induced by conditioned medium derived from separate MDA23 1 or 1 833/TR cultures, which indicates that a soluble factor produced by the tumor cells is capable of inducing MMP 13. One soluble factor that appears to be produced by 1 833iTR cultures is oncostatin M. Oncostatin M is an interleukin-6 family cytokine that is known to upregulate MMP13 synthesis and secretion during chondrogenesis. Genome-wide Affymetrix® analysis revealed, and qPCR analysis confirmed, that oncostatin M receptor-specific subunit RNA was also significantly upregulated in co-cultured osteoblasts. Therefore, breast tumor cells may be capable of initiating protein degradative changes in the bone microenvironment that are independent of the much studied osteolytic degradation initiated by osteoclast activation. / Medicine, Faculty of / Graduate

Medulloblastoma is the most common brain tumor in children and one third of the patients remain incurable. Tumor metastasis is one of the primary reasons for its high mortality rate. Despite evidence of overexpression of PDGFRα and PDGFRβ in metastatic medulloblastoma, their individual roles remain controversial and equivocal. Analysis of their specific signaling pathway in medulloblastoma cells revealed that PDGFRα and PDGFRβ signaling events lead to distinct cellular functions: while PDGFRβ stimulated cell proliferation and invasion, the expression of CD44 to regulate progression via c-Myc and inhibited cell death, PDGFRα displayed the opposite effects. Studies also revealed that c-Myc plays an intermediary role by regulating the downstream molecules in PDGFRβ signal pathway such as CD44 and NFB. NFB activity was found to be down- regulated in the absence of PDGFRβ pathway, with its activity restored by the overexpression of c-Myc. Analysis of medulloblastoma patient tissues without a prior knowledge of their metastatic nature further confirmed that PDGFRβ-CD44 axis regulate medulloblastoma metastasis. Co-inhibition studies performed by simultaneous inhibition of both PDGFRβ and c-Myc either by using siRNAs or by using pharmacological inhibitors demonstrated an enhanced inhibitory effect on medulloblastoma cell proliferation and migration. Using miRNA profiling of Daoy cells lacking either PDGFRβ or c-Myc alone or both, a set of miRNAs regulated by both PDGFRβ and c-Myc in common were identified. Integrative analysis of these miRNAs and their targets revealed that activation of PDGFRβ signaling and overexpression of c-Myc may enhance medulloblastoma progression via modulating the expression of several miRNAs such as miR-1280, -1260 and consequently regulating the expression of oncogenic molecules, such as Jagged 2 and CDC25A, respectively. Specific inhibition of miRNAs, miR-1280 and -1260, and JAG2 demonstrated their vital roles in medulloblastoma cell proliferation and migration. These findings suggest that the PDGFRβ-CD44 is a regulatory axis modulating medulloblastoma progression via c-Myc and targeting PDGFRβ/c-Myc/CD44 may provide a novel therapeutic strategy for the treatment of metastatic medulloblastoma.

During tumor progression and development of distant metastases, a subset of cancer cells undergoes transformation programs, such as epithelial-mesenchymal transition (EMT), to acquire enhanced migratory attributes to commence the metastatic cascade with the intension of achieving an active cell adhesion molecule-mediated organ-specific homing. Similarly, naive T cells reform the assemblage of their surface adhesion molecules during differentiation to activated T cells in order to successfully home to sites of inflammation and other extra-lymphoid organs for surveillance purposes. Sialyl-Lewis X (sLex) is well-known for mediating the homing of epithelial circulating tumor cellss (CTCs) and activated T cells to target sites through the interaction with endothelial selectins. Since glycan structures are not directly encoded by the genome, their expression is dependent on the glycosyltransferase (GT) expression and activity. Yet, the modulation of GTs during breast cancer transformation and in different molecular subtypes is still unknown. In addition, although the regulation of GTs during T cell activation is well-understood, the regulation at the epigenetic level is lacking. O-glycan-type sLex expression and E-selectin binding under static and flow conditions varies among molecular subtypes of breast cancer and upon the induction of EMT which is linked to the expression patterns of GTs. GTs displayed a significant prognostic value of in the association with the patients' survival profiles and in the ability to predict the breast cancer molecular subtypes from the expression data of a random patient sample. Also, GTs were able to differentiate between tumor and their normal counterparts as well as cancer types and glioblastoma subtypes. On the other hand, we studied the regulation of GTs in human CD4+ memory T cells compared to the naive cells at the epigenetic level. Memory T cell subsets demonstrated differential chromatin accessibility and histone marks within the promoters of the GTs genes. Moreover, they showed differential binding of pioneer and nonpioneer transcription factors (TFs). We proposed a model for the regulation of FUT7 during T cell activation that relies on the interplay between chromatin-remodeling and cell-fate-specifying TFs. Furthermore, we developed a fluorescent multiplex cell rolling (FMCR) assay to study the cell adhesion properties under physiological conditions. Compared to the conventional parallel plate flow chamber (PPFC) assay, the novel technique posses a high-throughput capacity which helps eliminate the inter-experimental variation problem by running multiple samples simultaneously and under competitive settings. We also developed a real-time analysis pipeline that enhanced the statistical power of the assay. Overall these modifications to the traditional parallel plate assay improves the reliability and results along with saving time and effort.

No description available.