REGULATION OF PITUITARY TUMORS PROLIFERATION INDUCED FOR THE FGF2/FGFR1 PATHWAY

VILLAFAÑE E.; PETITI J.P.; TORRES A.I.; SOSA L.

Congreso; Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2021

SAIC

The growth factors and their receptors dysregulation could lead to abnormal growth and progression of pituitary tumors. Previously, we demonstrated that the expression of Fibroblast Growth Factor 2 (FGF2) increased in experimental prolactinomas development, suggesting its participation in tumor progression. However, the molecular mechanisms that generate this effect still now unknown. The aim was to determine the role of FGF2, FGF receptor 1 (FGFR1) and MEK-ERK1/2 pathway in the pituitary tumor cells proliferation. Somatolactotroph (GH3) and corticotroph (ATt20) pituitary tumor cell lines were stimulated with FGF2 (10 and 100 ng/mL). The expression of FGFR1 was evaluated by western blot. Cell viability was determined by MTT assay after FGF2 stimulation for 24-48h in medium with or without 10% serum. Proliferative response was analyzed by BrdU uptake for 24h and ERK1/2 phosphorylation by western blot after FGF2 stimulus for 30min. Additionally, the MEK inhibitor PD 98059 (50uM) was used. Statistics: ANOVA-Post-test: Tukey. The FGFR1 expression was higher in GH3 than in ATt20. FGF2 induced a significant increase in cell viability in GH3 at 24 and 48h in both doses, while in ATt20 cells, the cell viability increase (p> 0.05) was only observed after FGF2 (100 ng/mL) stimulation for 48h. Considering that FGF2 effect in GH3 was higher, we continue working on this cell line. The expression levels of ERK1/2 phosphorylated increased after FGF2 (10 and 100 ng/mL) stimulus for 30min (p˂0.05 vs control). Cell viability and BrdU uptake was significantly higher in the cultures treated with FGF2 to both doses in presence of 10% serum, effect that was reverted with PD98059 co-incubation. These findings show that FGF2/FGFR1/ERK1/2 pathway participates in the increase of proliferation in GH3 lactosomatotroph tumor cells, which present greater expression of FGFR1, effect that was enhanced in serum medium which would be represent part tumor microenvironment in the tissue.