Changes in prolactin receptor location in prostate tumors

LÓPEZ-FONTANA, G.; REY, L.A.; SANTIANO, F.E.; LÓPEZ-FONTANA, R.; LÓPEZ-LAUR, J. D.; ZYLA, L.E.; VALDEMOROS, P.; GUERRERO-GIMÉNEZ, M.E.; FERNANDEZ-MUÑOZ, J.M.; GÓMEZ, S.E.; BRUNA, F. A.; GUGLIELMI, J.M.; CARÓN, R.W.; LÓPEZ-FONTANA, C.M.

ARCHIVOS ESPANOLES DE UROLOGIA.

Iniestares S.A.

Año: 2021 vol. 74 p. 419 - 426

0004-0614

Introduction: Prolactin (PRL) binds its receptor (PRLR) and stimulates cell proliferation, differentiation and survival in prostate cancer (PCa) cell lines via STAT5a, MAPK and AKT.Objective: To evaluate the expression of PRL and PRLR in normal and tumor prostate tissueswith different Gleason patterns.Methods: Samples of normal, benign prostatic hyperplasia and PCa with different Gleasonpatterns were selected from radical prostatectomy. The intensity, location and percentage ofstained cells for PRL and PRLR were evaluated by Immunohistochemistry. Co-localizationwas observed by confocal microscopy.Results: PRL was expressed diffusely and with a mild intensity in the cytoplasm of normaland tumor prostate luminal cells. Its expression only augmented in the Gleason 3 pattern (p0.0001). The immunostaining intensity and the percentage of positive cells for PRLR did notvary between normal and tumor tissues. However, the location of the PRLR was modified bythe tumorigenic process. In non-tumor tissues, PRLR expression was mostly in plasmamembrane in the apical zone of epithelial cells. In tumor tissues, it was expressed inintracellular vesicles. The co-localization of PRL and PRLR was demonstrated in normal andtumor tissues suggesting that PRL could be acting in an autocrine and paracrine manner.Conclusion: PRL and its receptor were present in the cytoplasm of the epithelial cells of thenormal and tumor prostate gland. In tumor tissues, the change in the location and appearanceof cryptic PRLRs that store PRL may keep active the different signaling pathways related tocell proliferation and survival.