Mechanism Of 17β-Estradiol Induced Proliferation And Invasion Of Papillary Thyroid Carcinoma Cells Through GPER1

Objection:To investigate the effects of G protein-coupled estrogen receptor1 (GPER1) on 17β-estradiol (E2) induced proliferation and invasion of papillary thyroid carcinoma (PTC).Methods:The expression levels of GPER1, EGFR and CXCR1 were analyzed in 68 cases of PTC using immunohistochemistry (S-P), and their correlations with the clinicopathological features were examined. Expression of GPER1 in BCPAP and K-1 were tested by Western blot and RT-PCR. K-1 cells were treated with E2, ICI182780 (inhibitor of estrogen receptor), the cell growth rates were tested by MTT assay; changes of cell cycle were analyzed by flow cytometry; the invasion and migration ability were determined by Transwell/Matrigel assay. K-1 cells were treated with E2, G1 (GPER1-selective agonist) and E2+G15 (GPER1-selective antagonist), the levels of phosphorylated ERK1/2, phosphorylated AKT and nuclear translocation of NF-κB were analyzed by Western blot. The levels of IL-8 were tested by ELISA.Results:The positive expression rates of GPER1, EGFR and CXCR1 were 76.5%,66.2% and 64.7% in the PTC tissue specimens, significantly higher than the nodular goiter group (P<0.01). High expression of GPER1, EGFR and CXCR1 was correlated with lymph node metastasis (P<0.05). The expression of GPER1 was positively correlated with EGFR and CXCR1 in PTC and lymph node metastatic carcinoma. The cell growth rates of BCPAP cells were 0, (13.5±1.5)%, (20.6±1.9)%, (11.3 ±1.2)% treated with E2 (0,10-7 mol/L,10-8 mol/L,10-9mol/L). When BCPAP cells were treated with E2 (10-8 mol/L) for 0,12h and 24h, the cell growth rates were 0, (12.0±1.4)%, (20.6±1.9)%(P<0.05). K-1 cells were treated with E2, E2+ICI182780 (10μmol/L) for 24h, the cell growth rates were (19.7± 0.9)%, (18.4±1.6)%(P<0.05). The proportion of S/G2 phase was increased. The potential of invasion and migration was promoted (P<0.05). After exposure to E2 at different time point (0,5min, 10min,15min,30min), the rapid increase of phosphory-lation levels of ERK1/2 and AKT in K-1 cells were observed at 10 and 15min. After exposure to E2 at different time point (0, 1h,2h,4h,8h), the nuclear translocation of NF-κB in K-1 cells were observed at 1h. K-1 cells were treated with E2, G1 (10 nmol/L) and E2+G15 (100 nmol/L) for different-time. The results showed that the E2-induced the activation of ERK1/2 and AKT, nuclear translocation of NF-κB and IL-8 secretion were inhibited by G15.Conclusion:The high expression of GPER1, EGFR and CXCR1 was correlated with lymph node metastasis in PTC patients. Meanwhile, there was a positive relation between them. E2 can promote proliferation and invasion of PTC K-1 cells through GPER1.