Is the stem cell population contributing to the development of the experimental pituitary adenoma?

CAROLINA B GUIDO, LILIANA V SOSA, NATACHA ZLOCOWSKI, PABLO A PEREZ, FLORENCIA PICECH, GABRIELA D MOYANO, SILVINA GUTIÉRREZ, JUAN P PETITI, JORGE H MUKDSI, ALICIA I TORRES

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedad Argentina de Investigación Clínica

Our previous results confirmed the presence of stem cell (SC) inadult pituitary gland and provided early evidences of cells expressingcancer stem cells (CSC) markers in experimental pituitary adenomas.The aim of this study was to evaluate possible changes inthe expression of CS: GFRa2, Oct-4, Sox2, Nestin, Progenitor (P):Sox9, and CSC: CD133 and CD44 markers, during experimentalpituitary tumor development, and later characterization of the SCin culture. The experimental model was performed in female Fischerrats, treated with 30mg of estradiol benzoate during 5 (5D), 10(10D), 20 (20D) and 30 (30D) days. Control group (C) included ratsin diestrous. SC/P and CSC markers were detected by immunofluorescence(IF) and Western Blot (WB). In vitro studies were doneusing C, 5D and 30D pituitary cell suspensions. The spheres werecharacterized by IF of SC/P and CSC markers and further estrogenstimulation the proliferation of C, 5D and 30D spheres was quantified.SC/P and CSC markers expression was detected in C, 5Dand 30D. Oct4, Sox2, GFRa2, Nestin and CD133 showed variationsin their distribution within the gland during treatment. We observedpositive cells for these markers in the marginal zone (MZ), and lowimmunostaining in adenohypophysis (AH) of C and 5D. In contrast,their expression was remarkable in AH of 30D, indicating a reorganizationof SC from the MZ to AH. The expression levels of GFRa2,Nestin, CD133 and CD44 increased significantly in 5D comparedto C and other periods of treatment. Sox2 didn´t show variationson its expression levels and Sox9 (P), decrease in 5D. This allowsto propose the participation of CS at early stage of tumor development.The pituispheres in culture were positive for SC/P and CSCmarkers. A significant increase of proliferation was shown in spheresobtained from 5D and 30D vs. C (p