Comprehensive ceRNA network analysis and experimental studies identify an IGF2-AS/miR-150/IGF2 regulatory axis in colorectal cancer

Recently, a growing body of studies has demonstrated that long non-coding RNA (lncRNA) can act as microRNA (miRNA) sponges to regulate protein-coding gene expression and play essential roles in tumor initiation and progression. In the present study, we constructed a competitive endogenous RNA (ceRNA) network and identified potential regulatory axes in colorectal cancer (CRC) through both bioinformation and experimental validation. Firstly, we obtained differentially expressed (DE) lncRNAs, miRNAs, and mRNAs by analyzing the RNA expression profiles of CRC retrieved from The Cancer Genome Atlas (TCGA) database and CRC patients' data from affiliated Hospital of Jiangnan University, respectively. Then, we established a ceRNA regulatory network of CRC that includes 23 lncRNAs, 7 miRNAs and 244 mRNAs. To further identify these lncRNA-miRNA-mRNA regulatory axes which might play vital roles in CRC tumorigenesis and prognosis, we performed additional analyses using comprehensive bioinformatic methods. Several ceRNA regulatory axes, which consist of 2 lncRNAs, 2 miRNAs and 5 mRNAs, were obtained from the network. Finally, the interactions and correlations among these ceRNA networks were validated by experiments on CRC cell lines and clinical tumor tissues, and a potential IGF2-AS/miR-150/IGF2 axis that perfectly conform to the ceRNA theory was determined. According to the qRT-PCR results, miR-150 overexpression remarkably decreased IGF2-AS and IGF2 expression. Meanwhile, IGF2-AS expression was positively correlated with IGF2 expression in tumor tissue of CRC patients. Besides, dual luciferase reporter assays indicated that miR-150 could bound to IGF2-AS and the 3'UTR of and IGF2. In general, the constructed novel IGF2-AS/miR-150/IGF2 network might provide potential mechanisms of CRC development, and could act as a promising target for CRC treatment.