Identification of functional circRNA/miRNA/mRNA regulatory network for exploring prospective therapy strategy of colorectal cancer.

Circular RNA (circRNA) has been reported to have great scientific significance and clinical value in multiple cancers including colorectal cancer (CRC). However, the biological function of most circRNAs in CRC is still in its infancy. Herein, we discovered the differential expressed circRNAs (DECs) between CRC tissues and matched adjacent using deep RNA sequencing and further confirmed the DECs expression by combining with another Gene Expression Omnibus dataset. Furthermore, we validated the expression of the top four upregulated circRNAs (hsa_circ_0030632, hsa_circ_0004887, hsa_circ_0001550, and hsa_circ_0001681) in both of paired CRC tissues and CRC cell lines. Then, a circRNA/microRNA/messenger RNA regulatory network was established and the Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed these four circRNAs participated in various biological processed including apoptotic process and multiple metabolic processes. Moreover, based on the regulatory network, three bioactive compounds (pergolide, pivampicillin, and methylergometrine) for the treatment of CRC were also found. In conclusion, this study improved our understanding of circRNAs and may also facilitate the finding of promising targets and biomarkers in CRC.