| Ovarian cancer is the most lethal cause of gynecological cancer deaths in the developing world and typically presents at an advanced stage when optimal debulking and platinum based-chemotherapy remain the cornerstone of management.Unfortunately,despite frequent initial responses to chemotherapy,these tumors almost invariably relapse.Efforts must be made to include comprehensive molecular profiling both at baseline and sequentially throughout the disease course,and studies investigating the usefulness of novel surrogate tumor biomarkers will likely be essential.Molecular-targeted accurate treatment is the trend.Previous studies,including those from our group,have revealed that phenethyl isothiocyanate(PEITC),a constituent of many edible cruciferous vegetables,not only affords significant protection against chemically induced cancer in animal models but also inhibits growth of cancer cells in culture and in vivo by causing cell cycle arrest and apoptosis induction.Few studies also suggest anti-angiogenic and anti-metastatic effects.However,whether PEITC inhibits human ovarian cancer cell metastasis and its underlying mechanisms is still not well elucidated.In the present study,we evaluated the inhibitory effects of PEITC in SKOV3 and HO8910 cells and examined PEITC-induced inhibition of invasion via CRM1 and mTOR-STAT3 signal pathway,the expression of CRM1 and mTOR were analyzed in a cohort of 40 ovarian tumors and 5 ovarian cell lines,To the best of our knowledge,our study for the first time demonstrates the anti-metastatic effects of PEITC in vivo in a novel ovarian tumor metastasis model and provides the rationale for further clinical investigation.Objective: To study the expression of CRM1 and mTOR in ovarian cancer tissue and its clinical relations,and to explore the mechanism of PEITC in regulating ovarian cancer metastasis and invasion.Methods:1.The expression of CRM1 and mTOR were detected by immunohistochemistry(IHC)in 40 cases of epithelial ovarian cancers and 10 cases of benign epithelial ovarian tumors in paraffin embedded tissues,quantitative reverse transcri-ptase PCR(QPCR)and western blot were used to detected the transcription and translation level of CRM1 and mTOR,respectively.The association between CRM1 and mTOR expression and clinicopathologic parameters was assessed by the Fisherexact test.The probability of overall survival was determined by the Kaplan-Meier and multivariate survival analysis was performed by using the Cox model.2.The effects of PEITC on SKOV3 and HO8910 cells metastatic and invasion ability were detected in vitro and in vivo.EOC cells were treated with 5μM or 10μM PEITC,0.1%DMSO for the control group,for 24 h or 48 h,Would healing assay and transwell assay were used to detect the migration and invasion ability.The SKOV3 ovarian cancer cells stably transfected with luciferase were injected into the enterocoelia of BALB/c-nu mice and the migration of cells was monitored using a non-invasive IVIS bio-luminescent imaging system,10μmol PEITC were by oral gavage for 6 weeks.3.QPCR and WB were used to detect the expression of CRM1 and mTOR-STAT3 pathway in SKOV3 and HO8910 cells after treated by PEITC for 24 h or 48 h,immunofluorescence analysis was used to detect the subcellular distribution of mTOR,to explore the mechanism of PEITC suppressing tumor metastasis and invasion in ovarian cancer.Results: Compared with benign ovarian tumors,CRM1 and mTOR expression level was significantly up-regulated in epithelial ovarian cancer,and was related significantly to advanced tumor stage(III,IV),type Ⅱ tumors and poor overall survival.CRM1 was associated significantly with mTOR expression.Treatment of SKOV3 and HO8910 cells with PEITC revealed a significant reduction of cell metastasis and invasion.Oral gavage of 10 μmol PEITC for 6 weeks inhibits the pelvic tumor number in nude mice.PEITC decreases CRM1 and mTOR expression and inhibits the nuclear export of CRM1,accompany down-regulating of mTOR-STAT3 pathway.Conclusions: The current results indicated that CRM1 and mTOR are overexpressed in a subpopulation of epithelial ovarian cancers with aggressive behavior and are related to poor patient outcome.A correlation also was demonstrated between CRM1 and mTOR expression.PEITC suppressed the motility and invasion of ovarian cancer cells in vitro and in vivo by inhibiting the nuclear export of CRM1 and via down-regulation of mTOR-STAT3 pathway. |
