The Effect Of G Protein-coupled Estrogen Receptor (GPER)on The Activation Of Phosphatidylinositol3-kinase-Akt(PI3K/Akt) Induced By17β-estradiol In Endometrial Carcinoma Cells.

ObjectiveEndometrial cancer is one of the common malignant tumors of the female reproductive tract, a serious threat to the health and lives of women, and its incidence is rising. As we all know, long-term high levels of estrogen effects without progesterone resistance can increase the risk of endometrial cancer. There are two mechanisms, first the classic theory is that estrogen binding to ER through the process of gene transcription, protein production at the genetic level to play a traditional "nuclear effects" role, recent studies also have shown that estrogen can activate endometrial cancer phosphatidylinositol3-kinase(PI3K)/protein kinase B (PKB, also known as Akt) signaling pathway, play the role of " non-gene transcription effect ", then promotion cells growth, What mediates this "non-gene transcription effects"? This "non-gene transcription effects" with estrogen binding membrane protein is most likely a G protein-coupled estrogen receptor(GPER). Because it has all the characteristics of combined estrogen interaction with estrogen in the estrogen-related tumors, activation of second messenger signaling system in tumor cells that promote tumor growth, the role of GPER in activation of PI3K/Akt effect is not clear. In this study, to investigate the expression of G protein-coupled estrogen receptor (GPER) and ER in the activation of phosphatidylinositol3-kinase AKT (PIAK/Akt) induced by17β-estradiol in endometrial carcinoma cells, Ishikawa and HEC-IA. Expression of GPER, ERa and ERβ protein in Ishikawa and HEC-1A cells were detected by immunocytochemistry method. Levels of GPER, ERa and ERβ were examined by western blot in endometrial cancer cell lines Ishikawa and HEC-IA after treated with10-6mol/L17p-estradiol (E2) at different time (0,15,30,60,120minutes).Methods1. First cultured Ishikawa and HEC-1A cells in vitro.2. Expressions of GPER, Akt and P-Akt, ERa and ERβ protein were detected by immunocyto-chemistry in Ishikawa and HEC-1A cells.3. Levels of GPER, Akt and P-Akt, ERa and ERβ were examined by western blotting in Ishikawa and HEC-1A cells after stimulation with10-6mol/1E2at different time (0,15,30,60,120min).Results1. In Ishikawa and HEC-IA cells, GPER was positive stained. ERa and ERβ were both positive stained in Ishikawa.2.1×10-6mol/L17β-E2, processing, Ishikawa and HEC-1A cells GPER protein level for15min was markedly increased (P<0.05), where Ishikawa cells for30min up to highest(0.192±0.004), HEC-IA cells for15min and reached the highest (0.184±0.006); Ishikawa and HEC-1A cells, Akt, activation levels from the treatment for15min markedly increased (P<0.05), which Ishikawa30min, when cells reached the highest (0.666±0.021), HEC-1A cells for15min and reached the highest (0.788±0.035); Ishikawa and HEC-IA cells, ERa and ERβ protein expression did not change significantly (P>0.05). Conclusion1. In endometrial cancer cells HEC-IA and Ishikawa, GPER are positive expression, the ER(3are negative expression in the HEC-1A, in the Ishikawa cells, the ERβ are positive expression.2. With the activation of Akt induced by estrogen in endometrial cancer cells, GPER performance consistent changes, while ERα and ERβ have no significant changes, suggesting GPER most likely mediated the activation of PI3K/Akt signaling pathway, involved in the effect of non-gene transcription in endometrial cancer.