Study On The Roles And Mechanisms Of PRKCE In Ovarian Cancer

Objective: Ovarian cancer is one of the most common malignancies in gynecology,and it is also one of the most lethal gynecological cancers.Ovarian cancer is highly heterogeneous,metastasic,and susceptible to drug resistance and recurrence with high mortality.Till now,initiation and progression of ovarian cancer has not been well defined yet.Treatment regimens for different subtypes of ovarian cancer are relatively simple,so there is urgent needs to improve treatment for ovarian cancer.Identifying and verifying novel druggable targets related initiation and progression of ovarian cancer,screening early diagnosis biomarkers,and developing highly effective molecular-targeted drugs to prevent tumor metastasis,drug resistance,and recurrence have become urgent in the study of ovarian cancers.The protein kinase C epsilon(PKCε,encoded by PRKCE)is a member of the PKC family and plays a key role in progression of many cancers.Overexpression of PRKCE is associated with malignant transformation of tumors and may promote metastasis of a variety of cancers.However,there are few studies on the mechanisms of PRKCE in initiation and progression of ovarian cancers.Therefore,studies on roles and mechanisms of PRKCE in ovarian cancer may define a new therapeutic target for ovarian cancer,and the studies may help build theoretical and experimental foundations for diagnosis,targeted therapy,and drug development for ovarian cancer.Methods: The data of ovarian cancer clinical specimens collected in the TCGA database and 86 clinical specimens of ovarian cancer patients were used to examine the relevance between PRKCE and ovarian cancer.Then,western blotting was used to detect the protein expression of PKCε in different ovarian cancer cell lines and normal ovarian cell lines.Afterwards,PRKCE was knocked down and overexpressed in ovarian cancer cell lines to study the effects of PRKCE on proliferation,migration,and invasion of ovarian cancer cell lines and related signaling pathways.Finally,a series of small hairpin RNAs(shRNA)were constructed and used to knock down PRKCE in ovarian cancer cell line.And they were used to validate the in vivo roles and mechanisms of PRKCE in the mouse lung metastasis model of ovarian cancer.Results: Data analysis of of ovarian cancer specimens in the TCGA database revealed that the DNA copy numbers and mRNA expression levels of PRKCE in serous ovarian cancer were significantly higher than those in normal ovarian tissues.And the DNA copy numbers and mRNA expression levels increased with the increase of stages of serous ovarian cancer significantly.Statistics also showed that more than half of ovarian cancer clinicalspecimens collected by us were serous ovarian cancers.PRKCE was highly expressed in serous,mucinous,and clear cell ovarian cancer in some patients versus normal people using immunohistochemistry assays.Western blotting showed that PKCε was highly expressed in serous ovarian cancer cell lines SKOV3 and A2780.Knockdown of PRKCE in ovarian cancer cell lines SKOV3 and A2780 with siRNAs significantly inhibited migration and invasion of ovarian cancer cells,but had no significant effects on proliferation.Overexpression of PRKCE had no significant effects on proliferation,migration,or invasion of ovarian cancer cell lines.Knockdown of PRKCE in ovarian cancer cell line SKOV3 showed that the protein expression of ZO-1,E-cadherin and Fibronectin were significantly up-regulated and that of slug and vimentin were down-regulated through Western blots.Protein expression of Akt decreased,and the protein levels of p-Akt,Stat3,and p-Stat3 were significantly down-regulated.Finally,the mouse lung metastasis model of ovarian cancer confirmed that shPRKCE can effectively inhibit ovarian cancer metastasis in mice.Conclusion: PRKCE likely has a high correlation with serous ovarian cancer.Knockdown of PRKCE can effectively inhibit migration and invasion of ovarian cancer cell lines.Knockdown of PRKCE likely down-regulate the downstream Akt or Stat3 signaling pathways,resulting in decreased migration and invasion of ovarian cancer cells.In addition,knockdown of PRKCE with shRNAs effectively inhibits metastass of ovarian cancer cells to lungs in vivo.