PO-254 G protein-coupled oestrogen receptor activation decreases prostate cancer cells viability concomitantly with altered proliferation, apoptosis, and metabolic profile

Abstract

IntroductionA panoply of studies have been indicating that estrogens are protective agents in prostate carcinogenesis. However, the physiological effects of estrogens in PCa mainly have been associated with the differential activation of the nuclear estrogens receptors (ER), with much less knowledge existing on the membrane ER. The G protein-coupled ER (GPER), known to be involved in the rapid nongenomic responses, has been linked to antiproliferative and proapoptotic effects and is a likely candidate mediating the ‘anti-carcinogenic’ actions of estrogens. This work aims to characterise the GPER’ role controlling proliferation, apoptosis and metabolism of PCa cells.Material and methodsThe nonneoplastic PNT1A cell line and neoplastic LNCaP, DU145 and PC3 cell lines were maintained in culture in RPMI 1640 medium. GPER expression pattern was characterised by Western blot. Fluorescent immunocytochemistry allowed determining the subcellular localization of GPER by colocalization with wheat germ agglutinin, calnexin, and hoescht. PNT1A, LNCaP, DU145 and PC3 cells were treated with the GPER specific agonist G1 (1 µM) for 24 hour. Cell viability was assessed by the MTT assay. The effect of GPER activation on cell proliferation, apoptosis and metabolism was assessed by analysing the expression of key proteins in each process. Also, the enzymatic activity of caspase-3 and LHD was measured. Glucose consumption and lactate production were determined using commercial kits.Results and discussionsGPER was differentially expressed in PCa cell line models depending on their aggressiveness and disease status. GPER expression was highest in the androgen-sensitive and less aggressive LNCaP cells and decreased in the more aggressive castration-resistant cell line models (DU145 and PC3). GPER was located at the cell membrane, endoplasmic reticulum, and also in the nucleus. The activation of GPER by G1 decreased PCa cells viability, concomitantly with altered expression of key regulators of proliferation and apoptosis. Furthermore, G1-stimulated cells displayed augmented caspase-3 activity comparatively to the control group. G1 treatment also modulated PCa cell metabolism with altered glucose consumption and lactate production.ConclusionGPER activation decreased viability of PCa cells whereas enhancing apoptosis. Also, PCa metabolic profile was altered in response to G1. These findings stimulate further research to ascertain the role of GPER as a therapeutic target.