The G protein-coupled receptor GPR30 mediates the proliferative and invasive effects induced by hydroxytamoxifen in endometrial cancer cells

Abstract

The selective ER modulator tamoxifen (TAM1Abbreviations: GPR30, G protein-coupled receptor 30; E2, 17β-estradiol; MMP, Matrix metal-loproteinase; MAPK, Mitogen-activated protein kinase; TAM, Tamoxifen; OHT, 4-Hydroxytamoxifen; ShGPR30-pGFP-V-RS, Short hairpin RNA (shRNA) constructs against GPR30 in pGFP-V-RS; shiv-pGFP-V-RS vector, HuSH 29-mer noneffective against enhanced GFP vector; EGFR, Epidermal growth factor receptor; ERK, Extracellular-signal-regulated kinase; DMEM, Dulbecco’s modified Eagle’s medium.1) is the most widely used ER antagonist for treatment of women with hormone-dependent breast tumor. However, long-term treatment is associated with an increased risk of endometrial cancer. The aim of the present study was to demonstrate new insight into the role of G-protein coupled receptor 30 (GPR30) in the activity of TAM, which promoted endometrial cancer. In endometrial cancer cell lines ISHIKAWA and KLE, the potential of 4-hydroxytamoxifen (OHT), the active metabolite of TAM, 17β-estradiol (E2) and G1, a non-steroidal GPR30-specific agonist to promote cell proliferation and invasion was evaluated. All agents above induced high proliferative and invasive effects, while the down-regulation of GPR30 or the interruption of MAPK signal pathway partly or completely prevented the action of the regent. Moreover, the RNA and protein expression of GPR30 was up-regulated by G1, E2 or OHT in both cell lines. The present study provided a new insight into the mechanism involved in the agonistic activity exerted by TAM in the uterus.