Made available in DSpace on 2015-07-22T20:50:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-27 / A progressão do câncer e metástase invariavelmente envolve a interação com fibroblastos e com o ambiente circundante. Os fibroblastos estromais auxiliam a proliferação de células tumorais, invasão e matástase pela produção de fatores de crescimento e citocinas e pela modificação do ambiente circundante do tumor, pela modulação da matriz extracelular (MEC). Os proteoglicanos pequenos ricos em leucina (SRLPs) são componentes ativos da MEC, podendo estar alterados no estroma circundante a tumores. O efeito das células estromais em células de câncer é bem descrito; entretanto, pouco é sabido sobre o efeito das células de câncer na biologia e comportamento dos fibroblastos, incluindo a expressão de proteoglicanos, colágenos e MMPs. Nossos resultados revelam uma redução significativa na expressão dos componentes da MEC como colágenos I, II, III e IV, e os SLRPs decorim, biglicam, lumicam e fibromodulina em co-cultura de fibroblastos e duas linhagens de células de câncer de próstata; PC3 (derivada de metástase óssea) e DU145 (derivada de metástase cerebral). Interessantemente, foi observada uma diminuição da expressão global de TGFβ quando co-cultivados com as células de câncer de próstata, bem como despolimerização dos filamentos de actina e aumento da expressão de vimentina e integrina 51. A distribuição da vimentina se alterou de padrão alterado para fibrilar, característico de células invasivas. A expressão de MT1-MMP foi aumentada, sendo localizada em protusões de invadopodia estendidas pela MEC. Nossos dados demonstram como células de câncer de próstata alteram drasticamente o fenótipo dos fibroblastos, possuindo provavelmente papel importante na migração dessas células pelo estroma. / During cancer cell growth many tumors exhibit various grades of desmoplasia, unorganized production of fibrous or connective tissue, composed mainly of collagen fibers and myofibroblasts. The accumulation of extracellular matrix (ECM) surrounding tumors directly affects cancer cell proliferation, migration and spread, therefore the study of desmoplasia is of vital importance. Myofibroblasts synthesize an amalgam of products including collagens and other ECM proteins, such as proteoglycans and are activated during a desmoplastic reaction. Small leucine rich proteoglycans have been characterized surrounding breast and pancreatic tumors and have the ability to suppress cell proliferation. In this study we have analyzed desmoplasia co-cultivating colorectal cancer cells (Caco-2 and HCT116) and myofibroblasts using various co-culture systems. Our findings demonstrate that direct cell-cell contact between myofibroblasts and colorectal cancer cells evokes an upregulation of the expression of ECM components (collagen I, collagen III, collagen IV, collagen V, biglycan and fibromodulin) by myofibroblasts. The ECM accumulation produced when myofibroblasts are co-cultivated with colorectal cancer cells appears unorganized and in bundles. This ECM accumulation slowed the migration and invasion of the colorectal tumor cells in both monolayer and 3-D co-culture systems. The participation of the ECM components analyzed in this study in desmoplasia is also demonstrated in vivo in human colorectal carcinoma tissue, validating our in vitro system. / TEDE / BV UNIFESP: Teses e dissertações

La périostine est une protéine matricellulaire préférentiellement exprimée aux sites de contraintes mécaniques, notamment le périoste, et dans le stroma associé à de nombreux types de cancers. En premier lieu, nous nous sommes attachés à évaluer la pertinence de cette protéine en tant que biomarqueur du métabolisme osseux et de la réaction stromale dans les métastases osseuses. Nous avons développé le premier dosage ELISA de la périostine circulante chez la souris présentant des caractéristiques analytiques (spécificité, précision) conformes aux exigences réglementaires. Ce dosage nous a permis de préciser l’implication de la périostine dans le métabolisme osseux et les métastases osseuses de cancer du sein. Nos données in vitro et in vivo suggèrent que la périostine n’est pas un indice direct du remodelage osseux, contrairement aux marqueurs biologiques conventionnels, mais une composante de l’ossification primaire. Nous avons aussi montré dans les métastases osseuses d’origine mammaire que la périostine est surexprimée par les cellules stromales de la métastase, comme cela a pu être observé au niveau des tumeurs primaires. Enfin, nous avons confirmé par une approche bioinformatique la relation étroite entre périostine et réaction stromale dans la plupart des tumeurs chez l’Homme. La périostine et d’autres protéines conjointement exprimées pourraient donc constituer un panel de marqueurs biologiques de la progression tumorale, certains pouvant se révéler comme nouvelles cibles thérapeutiques en oncologie. / Periostin is a matricellular protein preferentially expressed at sites subjected to mechanical constraints, including the periosteum, and in the stroma associated to several tumor types. We first aimed to evaluate the relevance of periostin as a biomarker of bone metabolism or stromal reaction in bone metastases. We developed the first ELISA for serum periostin in mouse with analytical characteristics (specificity, precision) that are in accordance with regulatory standards. This ELISA allowed us to specify further the involvement of periostin in bone metabolism and breast cancer bone metastases. Our in vitro and in vivo data suggested that periostin is a component of primary ossification rather than a direct index of bone remodeling, unlike conventional bone markers. In breast cancer bone metastases, we also showed that periostin is overexpressed by stromal cells associated with bone metastasis, in agreement with its localization in the stroma of primary tumors. Finally, using bioinformatics analyses of large datasets from various tumors in human, we confirmed the close relationship between periostin and the stromal reaction. Periostin and other co-expressed proteins could therefore constitute a set of biological markers of cancer progression, and/or appear as potential therapeutic targets.