CONICET | Buscador de Institutos y Recursos Humanos

Filamin A (FLNA) interacts with signaling molecules and membrane receptors to affect cell signal transduction and function. Epidermal Growth Factor Receptor (EGFR) is a major player modulating cell proliferation and hormone secretion in pituitary tumors, however, whether FLNA regulates EGFR expression affecting pituitary tumoral growth remains to be Elucidated. The aim of this study was to evaluate the impact of FLNA on proliferation, viability and hormone secretion in tumoral pituitary cells and establish if these alterations are mediated by EGFR signaling.Lactosomatotrophic GH3 cells were transfected for FLNA overexpression (GH3F+) and stimulated for 5, 10, 30 min and 24h with EGF (10 ng/ml). Protein expresión was analyzed by western blot and immunocitochemistry (ICC) and quantified by flow cytometry, protein subcelular localization was observed by indirect immunofluorescence (IFI), cell cycle progression was determined by cellular DNA content with Flow cytometry and cell viabilitywas analyzed by number of colonies formed in a clonogenic assay. The statistical analysis used was ANOVA-Tukey. FLNA overexpression induced a significant decreased of Ki67-labelled cells, reduced S/G2-M cell percentage, decreased cell viability, and inhibited PRL secretion. In order to elucidate the mechanism through FLNA overexpression impacts on these parameters, we evaluate membrane EGFR expression and EGF-induced signaling pathway activation.Plasmatic membrane EGFR was significantly reduced under FLNA overexpression in GH3 cells, with further decrease with EGF stimulation. Also, a consequent declined in ERK1/2 Phosphorilation in response to EGF was observed in GH3F+ vs. GH3. The results showed thatFLNA overexpression decreased lactosomatotroph cell growth and membrane EGFR Localization and activity, suggesting that FLNA may inhibit EGF-induced cell proliferation in Pituitary tumor cells

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