biostudies-literatureWinters BSNIGMS NIH HHS3386-96https://www.ebi.ac.uk/biostudies/studies/S-EPMC1525224biostudies-literatureUnknown17(8)Oncogenic transformation has been associated with decreased fibronectin (FN) matrix assembly. For example, both the HT-1080 fibrosarcoma and MAT-LyLu cell lines fail to assemble a FN matrix when grown in monolayer culture (2-dimensional [2D] system). In this study, we show that these cells regain the ability to assemble a FN matrix when they are grown as aggregates (3-dimensional [3D] system). FN matrix assembly in 3D correlates with decreased Raf-1 protein expression compared with cells grown in monolayer culture. This effect is associated with reduced Raf-1 mRNA levels as determined by quantitative RT-PCR and not proteasome-mediated degradation of endogenous Raf-1. Interestingly, transient expression of a Raf-1 promoter-reporter construct demonstrates increased Raf-1 promoter activity inMolecular biology of the cellThree-dimensional culture regulates Raf-1 expression to modulate fibronectin matrix assembly.PMC1525224GM-061487Robinson EEFoty RARaj BKCorbett SAWinters BSfalseThree-dimensional culture regulates Raf-1 expression to modulate fibronectin matrix assembly.Oncogenic transformation has been associated with decreased fibronectin (FN) matrix assembly. For example, both the HT-1080 fibrosarcoma and MAT-LyLu cell lines fail to assemble a FN matrix when grown in monolayer culture (2-dimensional [2D] system). In this study, we show that these cells regain the ability to assemble a FN matrix when they are grown as aggregates (3-dimensional [3D] system). FN matrix assembly in 3D correlates with decreased Raf-1 protein expression compared with cells grown in monolayer culture. This effect is associated with reduced Raf-1 mRNA levels as determined by quantitative RT-PCR and not proteasome-mediated degradation of endogenous Raf-1. Interestingly, transient expression of a Raf-1 promoter-reporter construct demonstrates increased Raf-1 promoter activity in2006-01-01T00:00:00Z2006 Aug2025-04-21T18:14:26.237Z2019-03-27T01:45:41ZS-EPMC15252241670757210.1091/mbc.e05-09-0849