| Objective:Due to high stability and tissue disease specificity,circ RNAs has become a research focus in the field of breast cancer molecular biology currently.In this study,the circ RNA expression microarray dataset of breast cancer was downloaded from the Gene Expression Omnibus(GEO)database,and R software was used to analyze differential circ RNAs expression profile of breast cancer,and then circ RNAs/mi RNAs/m RNAs and protein-protein interaction(PPI)networks were constructed.Subsequently,we studied the expression level and biological function of differentially expressed circ RNAs in breast cancer,and further revealed the molecular mechanism that circ RNAs may act as a competing endogenous RNAs(ce RNAs),to provide a research basis for circ RNAs as targets for clinical molecular diagnosis and treatment of breast cancer.Methods:(1)The circ RNAs expression microarray dataset of breast cancer GSE101123 was downloaded from GEO database,and the differentially expressed circ RNAs in breast cancer were analyzed by the limma package in R software.The regulation relationships of differentially expressed circ RNAs/mi RNAs/m RNAs were predicted by bioinformatics.Then,the PPI network was constructed and the hub genes were identified.(2)Real-time fluorescence quantitative PCR(q RT-PCR)was used to detect the expression level of differentially expressed circ RNAs in breast cancer cells,and hsa＿circ＿0000515 was selected as the object of our subsequent study.The expression of hsa＿circ＿0000515 in breast cancer tissues and adjacent tissues was detected by q RT-PCR.The si RNAs were transfected into breast cancer cells to knock down the expression of hsa＿circ＿0000515.The effects of hsa＿circ＿0000515 on the proliferation and migration of breast cancer cells were investigated by CCK-8,scratch healing assay and Transwell migration assay.(3)Bioinformatics was used to predict circ RNAs/mi RNAs/m RNAs axis,and dual-luciferase reporter assay was used to verify the targeting relationship.The protein expression level of target gene was detected by Western blot.Results:(1)By differentially expressed analysis of GSE101123 dataset,9 differentially expressed circ RNAs were obtained,of which 5 circ RNAs were up-regulated and 4circ RNAs were down-regulated.(2)The expression of hsa＿circ＿0000515 in breast cancer was significantly upregulated.CCK-8 cell proliferation assay,wound-healing assay and Transwell migration assay showed that,knocking down the expression of hsa＿circ＿0000515could significantly reduce the proliferation and migration of breast cancer cells.(3)Through bioinformatics analysis,we found the regulatory relationship of hsa＿circ＿0000515/mi R-1296-5p/CDK2 axis.The dual-luciferase reporter assay showed that luciferase activity was significantly decreased after upregulation of mi R-1296-5p expression.Western blot analysis showed that knocking down the expression of hsa＿circ＿0000515 could regulate the protein expression of cyclindependent kinase-2(CDK2).Conclusions:(1)Hsa＿circ＿0000515 was upregulated in breast cancer cells and tissues,suggesting that hsa＿circ＿0000515 may play an important role in the development of breast cancer and is expected to be a new diagnostic marker.(2)Knocking down the expression of hsa＿circ＿0000515 could inhibit the proliferation and migration of human breast cancer cells.(3)Hsa＿circ＿0000515 could act as a sponge of mi R-1296-5p to promote breast cancer progression through regulating CDK2 expression. |
