Search

Introduction: Glioblastoma is a highly malignant brain tumor with a high-invasive phenotype, so the prognosis is unfavorable, even in response to multidisciplinary treatment strategies. Obviously, therefore, a better therapeutic strategy is needed. Resveratrol has been reported to be one of the most potent chemopreventive agents inhibiting the cellular processes associated with tumor development, including initiation, promotion, and progression., Materials and Methods: In this study we used RT-PCR, western blot and SDS-zymography to investigate the effect of resveratrol on the expression of genes and proteins involved in the extracellular matrix remodeling associated with tumor invasion in human cultured glioblastoma cells treated for 24, 48 and 72 h. We analyzed the expression of matrix metalloproteinase-2 (MMP-2), the main mediator of glioblastoma invasiveness, and the Secreted Protein Acidic and Rich in Cysteine (SPARC), involved in the regulation of cell-matrix interactions., Results: Our results show a dose-related decrease of MMP-2 mRNA and protein levels 72 h after resveratrol treatment, and lower SPARC gene and protein expression 72 h after resveratrol treatment. This indicates that resveratrol may influence the two major factors in the ECM remodeling occurring with tumor invasion, suggesting it may have uses as a therapeutic agent for brain tumors.

Background: Secreted protein acidic and rich in cysteine (SPARC) is a glycoprotein that mediates cell-matrix interactions. In adults, its expression is mostly limited to tissue undergoing remodeling. During the development of Cyclosporin A (CsA)-induced gingival overgrowth (GO) a remodeling of the connective compartment occurs. By contrast, clinical trials showed that FK506 is not related to GO. SPARC expression and its involvement in GO is unknown. Our aim was, therefore, to analyze the effect of CsA and FK506 on SPARC gene expression., Methods: Cultured human gingival fibroblasts were incubated with CsA, FK506 or with their vehicle (VH) for 24, 48 and 72 h. SPARC gene expression was determined by RT-PCR., Results: SPARC mRNA levels tended to increase 72 h after CsA treatment, whilst they are undetectable in FK506-treated fibroblasts, compared to VH., Conclusion: This gene expression profile is consistent with the involvement of SPARC in the mechanisms leading to the development of CsA-induced GO. By contrast, the undetectable SPARC mRNA levels in FK506-treated fibroblasts suggest that FK506 may be associated with a role of ECM stabilization, that does not induce GO.

In a significant number of cases (25-81%) immunosuppressant treatment with cyclosporin A (CsA) is associated with gingival overgrowth, seriously interfering with the functions of mastication and speech. In CsA-induced gingival enlargement, quantitative modifications of the extracellular matrix components occur, and collagen (COL) metabolism and matrix metalloproteinases (MMPs) have been suggested as being the main targets. Since the mechanisms at the basis of CsA-induced gingival overgrowth are not yet completely understood, our aim was to analyze the effect of CsA on COL turnover in cultured human gingival fibroblasts. Cultured human gingival fibroblasts from four healthy volunteers were incubated with CsA (800 ng/ml) or with its vehicle (VH) for variable intervals of time (24, 48, 72 h). Fibroblast morphology was studied by light and electron microscope. Collagen type I (COL-I), MMP-1, MMP-2, TIMP-1 and TGF-beta1 mRNA were determined by RT-PCR; COL-I and MMP-1 by dot blot, and MMP-2 by zymography. Our results evidenced an up-regulation of COL-I and TGF-beta1 gene expression 72 h after CsA treatment. MMP-1, MMP-2 and TIMP-1 mRNA levels are affected but not significantly. Protein analysis revealed COL-I increase at all the considered times and, 72 h after CsA treatment, reduced collagenolytic levels. Our data suggest that COL accumulation during CsA-induced gingival overgrowth may be mainly sustained by an altered COL-I degradation due to decreased MMP-1 activity. However, interindividual differences of collagenase levels after CsA treatment suggest that a genetic predisposition to develop gingival overgrowth may be relevant.