Studies On Function And Molecular Mechanisms Of Ceramide Synthase 6 In Serous Ovarian Cancer

ObjectiveOvarian cancer is the most common malignant tumor in gynecologic tumors worldwide.Serous ovarian cancer is the most common type of epithelial ovarian cancer.Its pathogenesis remains unclear.Epidemiological and genetic analysis found that the occurrence of ovarian cancer is related to gene mutations,accompanied by changes in PI3K/AKT/mTOR,RAS/RAF/MEK pathways.In recent years,the study of the Ceramide Synthases in the field of oncology has received increasing attention.Ceramide Synthase 6(CerS6)mainly synthesizes C16:0-ceramide and is involved in the tumorigenesis and progression of various tumors.We found that CerS6 was highly expressed in serous ovarian cancer tissues through database analysis,and the expression of CerS6 was negatively correlated with the prognosis of serous ovarian cancer.The purpose of this study was to investigate the expression of CerS6 in ovarian tissue and its function in serous ovarian cancer cells and to explore its corresponding mechanism.Methods1.Database analysis and immunohistochemistry were used to detect the expression of CerS6 in serous ovarian cancer tissues and the relationship between high expression of CerS6 and clinicopathological characteristics,so as to evaluate the clinical significance of CerS6.2.In vitro and in vivo,the function of CerS6 on proliferation,invasion,migration,apoptosis and cell cycle of serous ovarian cancer cells was detected by CCK-8,subcutaneous xenograft experiments,transwell assay,scratch assay,flow cytometry and Western Blot assay.3.Gene Set Enrichment Analysis and R software were used to enrichment analysis,RNA-seq was used to compare the transcriptome changes of serous ovarian cancer cell OVCAR8 after silencing CerS6,and the differentially expressed genes were analyzed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis.4.Western Blot was used to compare the activation of related molecules in the AKT/mTOR/4EBP1 signaling pathway in serous ovarian cancer cells OVCAR3 and OVCAR8 after silencing CerS6.Results1.The results of database analysis showed that CerS6 expression was significantly higher in epithelial ovarian cancer than in benign ovarian tissue,and the expression of CerS6 was negatively correlated with the prognosis of ovarian cancer.The results of immunohistochemistry showed that CerS6 was highly expressed in serous ovarian cancer and was closely related to the pathological grade and clinical stage of serous ovarian cancer.2.In vitro,silencing CerS6 significantly inhibited the proliferation,migration and invasion of serous ovarian cancer cells,and promoted the ability of cells to apoptosis.In vivo,silencing CerS6 can significantly inhibited the size and growth of subcutaneous tumors in nude mice.Overexpression of CerS6 significantly promoted the proliferation and migration of serous ovarian cancer cells.3.The results of GSEA analysis and R analysis showed that the differential gene was most involved in DNA replication process and cell cycle after silencing CerS6.The RNA-seq results showed that silencing CerS6 could significantly affect the cell cycle of serous ovarian cancer.The proportion of cells in the G2/M phase of serous ovarian cancer cells OVCAR3 and OVCAR8 increased after silencing CerS6,but had no significant effect on G1 phase,and the expression levels of cell cycle G2/M phase related proteins(CDK1 and CCNB1)were found significantly reduced.4.Western Blot results showed that the expression of p-AKT,p-mTOR and p-4EBP1 was significantly decreased after silencing CerS6,while the expression levels of AKT,mTOR and 4EBP1 were not significantly changed.Conclusions1.CerS6 is highly expressed in epithelial ovarian cancer tissues,and the high expression of CerS6 is closely related to the pathological grade and clinical stage of serous ovarian cancer.Therefore,CerS6 is expected to be a new prognostic marker for serous ovarian cancer.2.High expression of CerS6 can promote the proliferation,migration and invasion of serous ovarian cancer cells,inhibit their apoptosis and affect the G2/M phase of the cell cycle.3.CerS6 may promote the proliferation,invasion and metastasis of ovarian cancer cells by activating the AKT/mTOR/4EBP1 pathway.CerS6 is expected to be a new therapeutic target for serous ovarian cancer.