Estudo das alterações de proteoglicanos e glicosaminoglicanos em linhagens celulares de câncer colorretal humano

• Ano de defesa: 2009
• Autor(a) principal: Ricci, Ritchelli [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Câncer colorretal; Estroma; Potencial metastático; Proteoglicanos; Glicosaminoglicanos
• Link de acesso: https://repositorio.unifesp.br/handle/11600/9541

Proteoglycans (PG) are complex macromolecules composed of linear polysaccharide chains, the glycosaminoglycans (GAGs), covalently attached to a core protein. These GAG chains contain sulphate groups at various positions, giving rise to specific domains, which allows them to interact with extracellular matrix molecules, including various growth factors. In this study, we have used a transwell coculture system to analyse the interaction between human fibroblasts stromal cells and human colonic carcinoma cell line (Caco-2) and investigate the effects of this interaction on cell proliferation and glycosaminoglycans synthesis. Soluble components exchanged between the cell lines in Transwell system caused a marked increase of Caco-2 cell proliferation, not observed on fibroblasts. An increase of GAGs biosynthesis was observed in both cell lines, whereas a prominent increase of CS was observed mainly in stromal cells, as determined by incorporation of 35SNa2SO4. Confocal microscopy showed significant increase of versican production by fibroblasts cells. TGF-â was also tested exhibiting a significant increase on GAG synthesis mainly in fibroblasts cells, producing a strong CS-stimulating response. These results suggest that this growth factor may be responsible for the CS increase observed in stromal cells. Caco-2 cells previously analyzed in this work were used to compare with a cell line with increased metastatic potential, HCT116. A normal rat intestinal epithelium cell line, IEC-6 was used as control. Labeling of cells with 35S-Na2SO4 and investigation of GAGs with specific enzymes showed an increased 6-O-sulfation of HS and CS. GAGs structural data were confirmed by Real Time PCR with elevation of specific heparan-6-O-sulfotransferase mRNA expression on Caco-2 and HCT116 cells, compared to IEC-6. The most extensively studied aspect of relationship between HS fine structure and growth factor signaling to date is the possible involvement of 6-Osulfation in the activation of FGF signaling. High levels of chondroitin-4,6-O-sulfotransferase expression was found only in HCT116 cells, whose CS structure contained GalNAc,4,6-sulfate, present on tetrasaccharides and disulfated disaccharides. The participation of the oversulfated structure on CS has been shown to promote tumoral cell motility. Whether these structural data obtained in this work correlate to the mentioned biological functions, remains to be elucidated.