The Role Of Gonadotrophin And Its Receptor In Ovarian Cancer Cell Proliferation,Invasion And Migration

Ovarian cancer is the leading cause of death from gynecological tumors and is the fourth most frequent cause of death from cancer in women.Ovarian cancer is highly lethal mainly because of occult metastases within the peritoneal cavity and the advanced stage at detection when curative therapy is ineffective.80-90%of ovarian cancer are thought to arise in ovarian surface epithelium.The etiology of ovarian epithelial cancer(OEC) is likely to be multifactorial with genetic,hormonal,and environmental factors playing a role.Based on numerous epidemiologic studies, there is a clear trend of decreasing risk with increasing numbers of pregnancies,with the extent of protection being related to the length of the pregnancy,and the duration of breast feeding.There is also a clear decrease in risk with length of oral contraceptive(OC) use.OC use for one year approaches the protective effect achieved by a full-term pregnancy.These protective factors are linked to an interruption in ovulation and related cyclic hormonal changes.Causative hypotheses which have been suggested to explain these observations involve 'incessant ovulation', increased exposure to gonadotropins and increased exposure to the high levels of sex-steroid hormones that occur within the ovary during a normal menstrual cycle. The gonadotropin theory of ovarian cancer proposes that elevated serum gonadotropins,follicle-stimulating hormone(FSH) and luteinizing hormone(LH), contribute significantly to the development of ovarian cancer.In this study,the plasmid constructed with FSHR gene was transfected into ovarian cancer cells to investigated the roles of FSHR and its ligand in ovarian cancer development. Moreover,the distribution of gonatrophin receptor in in women's abdominal cavity was determined,and their roles were further illuminated.In previously report,it was noticed not only there was many similar bio-functions between FSH and LH,but also many differences.In our previous work,it was observed that treatment with FSH resulted cell proliferation,while LH had no any effect on cellular growth,the detailed molecular mechanism remain clarified.Since OEC progression involves metastasis and occurs more common in high godatrophin status,understanding the role godatrophin receptor expression and mediation via its ligand in cellular and molecular levels may help to provide a new way of cancer prevention and control. Objective:We previously showed that the expressing level of FSH receptor(FSHR) increased from ovarian epithelial inclusions(OEIs) to benign ovarian epithelial tumors(OETs) and to borderline OETs,whereas FSHR levels decreased with an increase in carcinoma grade.However,the precise role of FSHR in ovarian epithelial carcinogenesis remains unclear.The aim of this study is to investigate the role of FSHR in OET development.Methods:Overexpression FSHR was carded out by transfecting human FSHR into MCV152 cells.Cell growth rate,cell cycle,and the invasive capacity were studied in FSHR-overexpressing OET cells.Multiple gene products related to cellular growth and cancer invasion were analyzed in the above setting to explore the potential molecular mechanisms associated with the observed findings.Result:MCV152 cells with FSHR overexpression showed an increased cellular proliferation with a significant increase of cell numbers in S and G2/M phases and increased invasive capacity.The above effects are associated with reduced level of prohibitin and RⅡ-βexpression and increased level of HER-2/neu,c-Myc,and EGFR expression.Conclusion:Overexpression of FSHR may be associated with an elevated level of OET cell proliferation via an enhanced level of potential oncogenic pathways. Therefore,our findings suggest that overexpression of FSHR may play a role in OET development.PartⅡThe distribution of gonadotrophin receptors in women's abdominal cavityObjective:To investigate the relationship between ovarian cancer development and gonadotrophin and its receptor. Methods:The real-time PCR was used to determine the expression of FSHR and LHR in peritoneum.Result:It showed a decline trend of FSHR expression in peritoneum with the increase distance far from ovary,while similar pattern was not observed in LHR expression.Conclusion:Maybe the high concentration FSH or FSHR play a very important role in ovarian cancer development.PartⅢThe Molecular Mechanism of Gonadotrophin in Ovarian Epithelial CarcinogenesisObjective:Despite evidence that luteinizing hormone(LH),one of the gonadotropins, contributes to ovarian cancer metastasis and invasion via regulation of MMPs (MMP2&9),the detailed molecular mechanism remains clarified.Prohibitin,as a potential tumor suppressor gene,plays an anti-proliferative role in tumorigenesis.A major goal of this study is to elucidate the relationship between prohibitin and MMPs in cells stimulated by LH,and the underlying signal pathways.Methods:The expression of LH receptor(LHR) in ovarian epithelial tumor cells was determined by RT-PCR to guarantee the suitability of cell systems.Western blot was performed to examine the expression of prohibitin and MMPs in cells stimulated by LH at different doses,but also the signal pathways of ERK1/2 and AKT in cells pretreated by their corresponding inhibitors.RNA Interference to knockdown prohibitin followed by MTT was carried out to demonstrate the role of prohibitin in OEC development.Result:A significant increase of OET cell proliferation was observed after prohibitin was silenced.Dose-dependent expressions of prohibitin,MMPs and time-dependent phosphorylation of ERK and AKT by LH were observed.Moreover, with the addition of inhibitors to ERK and AKT,cells showed reduced expressions of prohibitin and MMPs regardless of LH treatment.A same expression trend existed between prohibitin and MMPs.Besides,LH showed no significant effect on proliferation. Conclusion:Downstream factors of prohibitin and MMPs,dependent on the activity of signal pathways of ERK1/2 and AKT are involved in the mediation by LH in OEC development.The balancing roles of prohibitin and MMPs are responsible for the no effect by LH on cell growth.