The Role Of CircRNA-miRNA Axis In Epithelial-mesenchymal Transformation Of Prostate Cancer

Background and objective:Epithelial-mesenchymal transition（EMT）plays an important role in the progression and metastasis of prostate cancer.circRNA-miRNA axis is closely related to the occurrence,development and metastasis of prostate cancer.The purpose of this study was to screen and identify the differentially expressed circRNA and miRNA in prostate cancer cells before and after EMT,to explore the molecular mechanism of circRNA-miRNA axis in the process of prostate cancer cell EMT,and to further understand its role and significance.Methods:In this study,EMT,was induced by interferon-γ（IFN--γ）in PC-3MIE8 cells and verified at cellular and molecular level by Transwell test and Western blot analysis,respectively.High-throughput sequencing technique was used to screen the differentially expressed circular RNA（circRNA）and micro RNA（miRNA）before and after IFN-γ treatment.CircRNA and miRNA related to EMT were further identified by real-time quantitative PCR（qPCR）.In addition,the relationship among circRNA,miRNA and mRNA is predicted by software and database.Results:After the cells were treated with IFN-γ Western blot analysis was performed to detect the expression level of EMT markers,the expression of E-cadherin was down-regulated and the expression of Twist was up-regulated.The results of Transwell assay showed that IFN-γ promoted the migration and invasion of PC-3M IE8 cells,suggesting that IFN-γ could induce epithelial-mesenchymal transformation of PC-3M IE8 cells.In addition,the results of high-throughput sequencing showed that there were 827 up-regulated and 1279 down-regulated circRNA,39 and 2076 downregulated miRNA in IFN-γ group compared with the control group.KEGG analysis showed that both differentially expressed circRNA and differentially expressed miRNA were enriched in the MAPK signal pathway related to EMT.The results of qPCR showed that the expression of hsa_circ₀001085,hsa_circ₀004916,hsa_circ₀001165,hsa-miR-196b-5p and hsa-miR-301b-3p in IFN-γ group was consistent with that of sequencing.hsa_circ₀001165 and hsa_-circ₀001085 were used to construct the network of circRNA-miRNA-mRNA.Conclusion:hsa_circ₀001165 may regulate the expression of tumor necrosis factor（TNF）through hsa-miR-187-3p to induce EMT in prostate cancer cells.In addition,hsa_circ₀001085 may indirectly regulate PI3K-Akt signal pathway and TGF_β signal pathway through has-miR-196b-5p and has_miR₄51a to induce EMT.