The Function And Mechanism Of Novel Estrogen Receptor GPER In Liver Tumorigenesis And Progression

Primary liver cancer is characterized by high degree of malignancy,difficult treatment,easy recurrence and metastasis,and poor prognosis.Thus,it is of great significance to study the molecular mechanism of liver cancer and find potential therapeutic targets.This study explored the role of a novel estrogen receptor GPER in liver cancer and its related mechanisms.Our findings suggested the potential use of GPER-related signaling pathway in molecular therapeutic targets and prognosis prediction of liver cancer.The expression of GPER in hepatocellular carcinoma and its clinical significanceObjectives: To investigate the expression of GPER in liver cancer and its clinical significanceMethods: Immunohistochemistry was performed to detected the GPER expression and localization in 141 archival paraffin-embedded,formalin-fixed human hepatocellular carcinoma tissues,paired 30 normal liver tissues.And GPER distribution of HCC was correlated to clinicopathologic variables of tumors.Western blotting was used to determine the GPER expression in 6 postoperative hepatocellular carcinoma tissues,paired 6 normal liver tissues.Kaplan-meier method was used for survival analysis of different groups.Results:(1)There was a significant difference between the positive expression rate of GPER in normal liver tissues(90%,27/30)and that in liver cancer tissues(70.9%,100/141)(P<0.01).(2)Statistical analysis of clinicopathological variables suggested that positive GPER expression was correlated with some clinical parameters,such as: female(P=0.043),HBs Ag negative(P=0.036),small tumor(<5cm)(P=0.002)and low AFP level(<400ng/ml)(P=0.014).(3)western blots suggested that the expression abundance of GPER in normal liver tissues was higher than that in liver cancer tissues.(4)the survival time of HCC patients with GPER positive was significantly longer than that of those with GPER negative(P=0.004).Conclusion: GPER may be a protective factor in patients with HCC.Biological effects and regulatory mechanisms of GPER activation in hepatocellular carcinoma cellsObjectives: To investigate the role and mechanism of GPER in liver cancer cells.Methods: The expression of GPER in liver cancer cell lines was detected by real-time quantitative fluorescence PCR,western blot and immunofluorescence.Western blotting was used to detect the activation of GPER downstream pathway by gper-specific agonist G1.Cell cycle,cell apoptosis and cell proliferation were detected by flow cytometry and CCK8.RNA interference,gene cloning and pathway small molecule specific inhibitors have clarified the role and mechanism of GPER in HCC.Results: The expression of GPER was higher in HCCLM3 and SMMC-7721 and was lower in Hep G2.G1/GPER can sustainably activate the EGFR/ERK signal and temporarily activate the EGFR/AKT signal in HCC cells.The G1/GPER-induced EGFR/ERK signal can inhibit the activity of liver cancer cells,while the EGFR/AKT signal has no similar biological effect.Conclusion: G1 inhibits HCC cell growth by activating the GPER/EGFR/ERK pathway.Clinical significance and in vivo biological effects of GPER/ERK signaling in hepatocellular carcinomaObjectives: To investigate the clinical significance and in vivo biological effects of GPER/ERK signaling in liver cancer.Methods: Immunohistochemistry was used to detect the expression and localization of p-ERK in 141 cases of primary hepatocellular carcinoma,and the correlation between its expression and GPER expression was clarified.Western blotting was used to detect the expression consistency of GPER and p-ERK in liver cancer tissues of 6 patients after operation.Kaplan-meier method was used for survival analysis of different groups of GPER/ERK expression.The inhibitory effect of GPER/ERK signal on hepatocellular carcinoma cells was verified in vivo using nude mouse hepatocellular carcinoma implantation model.Results:(1)significant differences in the expression of p-ERK in GPER expression positive(72/100,72.0%)and expression negative liver cancer tissues(12/41,29.3%)(p <0.0001).(2)The expression level of p-ERK in 6 cases of liver cancer was highly consistent with that of GPER.(3)Patients with GPER/ERK signal activation had a longer overall survival time than other types of patients(P<0.0001).(4)In the experiment of transplanted tumor of liver cancer in nude mice,the average volume of G1 group on 56 days decreased to 0.20 times that of the control group(P<0.01).(5)treatment with small molecule specific inhibitors of the GPER/EGFR/ERK pathway can significantly reduce the inhibitory effect of G1 on the growth of transplanted tumors.Conclusion: GPER-mediated ERK signal has a protective effect on liver cancer patients.GPER activation inhibits the growth of transplanted HCC tumors through EGFR/ERK signaling.