Filamin A alters secretion, proliferation, and cell morphology of pituitary tumour cells

JONATHAN TOLEDO; PABLO A. PÉREZ; ANA L. DE PAUL; ALICIA I. TORRES; SILVINA GUTIÉRREZ

online

Congreso; Reunión Anual de las Sociedades de Biociencia, Sociedad Argentina de Investigación Clínica (SAIC).; 2021

SAIC

Filamin A (FLNA) is a promiscuous protein, with a multiplicity of functions, being its canonical role an acting binding protein which is related to cytoskeleton rearrangement, but also having non canonical roles as a scaffold protein related to signal transduction or exerting gene expression regulation. The role of FLNA expression and function in tumours is described as dual, having found to promote or inhibited tumour progression in a tissue and subcellular localization dependent manner. Despite the progress being made in the past years, FLNA impact in prolactin-secreting pituitary tumours remains elusive, possibly due to the variety of factors that modulate its final action. This work aims to determine the impact of FLNA expression levels in global cellular processes in the tumoral somatolactotropic cell line GH3. Transfected GH3 cells for FLNA overexpression (GH3F+) were used. FLNA expression and prolactin secretion levels was analysedby Western blot, FLNA subcellular localization by indirect immunofluorescence (IFI), viability by clonogenic assay, cell cycle progression by flow cytometry, Ki67 index by Immunocitochemistry (ICC), and cellular morphology was performed by flow cytometry analysis and optical microscopy. The statistical analysis used was ANOVA-Tukey. FLNA localization was found in the nucleus and cytoplasm in GH3 and GH3F+. FLNA overexpression significantly decreased cellular viability (23% less colonies formed) and proliferation capacity (25% less Ki67-labelled cells). Morphological analysis showed double number of pleomorphic cells, longer cellular protrusions and a decrease in granularity and size in GH3F+. Furthermore, PRL secretion was decreased in GH3F+. These results show that FLNA has a significant global impact in the survival and function of tumoral PRL secreting cells, inhibiting proliferation and secretion, placing this protein as a potential therapeutictarget to prolactinomas resistant to conventional treatment.