title: Differential proteomic analysis of the anti-proliferative effect of glucocorticoid hormones in ST1 rat glioma cells.
abstract: Glucocorticoid hormones (GCs) exert a potent anti-proliferative activity on several cell types. The classic molecular mechanism of GCs involves modulation of the activity of the glucocorticoids receptor, a transcriptional regulator. However, the anti-proliferative effect of GCs may also involve modulation of processes such as translation, subcellular localization and post-translational modifications, which are not reflected at the mRNA level. To investigate these potential effects of GCs, we employed the proteomic approach (two-dimensional electrophoresis and mass spectrometry) and the ST1 cells, obtained from the C6 rat glioma cell line, as a model. GC treatment leads ST1 cells to a complete transformed-to-normal phenotypic reversion and loss of their tumorigenic potential. By comparing sets of 2D nuclear protein profiles of ST1 cells treated (or not) with hydrocortisone (Hy), 13 polypeptides displaying >or=two-fold difference in abundance upon Hy treatment were found. Five of these polypeptides were identified by peptide mass fingerprinting, including Annexin 2 (ANX2), hnRNP A3 and Ubiquitin. Evidence obtained by Western blot analysis indicates that ANX2 is present in the nucleus and has its subcellular localization modulated by GC-treatment of ST1 cells. Our findings indicate complementary mechanisms contributing to the regulation of gene expression associated with ST1 cells' response to GCs.
authors.affiliation: Instituto de Química, Universidade de São Paulo, 05508-900 SP, São Paulo, Brazil.
authors.forename: Marcos A A
authors.initials: MA
authors.lastname: Demasi
authors.forename: Wagner R
authors.initials: WR
authors.lastname: Montor
authors.forename: Gabriela B
authors.initials: GB
authors.lastname: Ferreira
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Pimenta
authors.forename: Letícia
authors.initials: L
authors.lastname: Labriola
authors.forename: Mari C
authors.initials: MC
authors.lastname: Sogayar
mesh_terms: D000818:Animals; D017306:Annexin A2 / Q000032:analysis / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects*; D005910:Glioma / Q000473:pathology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006854:Hydrocortisone / Q000494:pharmacology; D013058:Mass Spectrometry; D009687:Nuclear Proteins / Q000032:analysis; D010449:Peptide Mapping / Q000379:methods; D040901:Proteomics; D051381:Rats; D014407:Tumor Cells, Cultured
chemical_list: D017306:Annexin A2; D005938:Glucocorticoids; D009687:Nuclear Proteins; D006854:Hydrocortisone