A Preliminary Study on the Pathogenesis of Colorectal Cancer by Constructing a Hsa-circRNA-0067835-miRNA-mRNA Regulatory Network

Background: Increasing evidence shows that circular RNAs (circRNAs) play a key role in the development of colorectal cancer (CRC). An interesting candidate RNA in this context is hsa-circRNA-0067835 (circIFT80), but its network of actions is still unclear. Methods: Big data mining technology was used to explore the downstream microRNAs (miRNA) and messenger RNAs (mRNA) of the circIFT80 network. A regulatory network, comprising circIFT80 and its corresponding miRNAs and mRNAs, was derived to preliminarily explore the potential mechanism of circIFT80 in CRC. Finally, the proposed regulatory network was experimentally verified at the cellular level. Results: A total of 6 miRNAs were screened, of which hsa-miR-197-3p, hsa-miR-370-3p and hsa-miR-377-5p may be the most potential downstream miRNAs of hsa-circRNA -0067835 in CRC. A total of 74 up-regulated genes with opposite miRNA expression were selected for subsequent verification. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases revealed that the target genes occurred more frequently in cancer-related pathways. In addition, protein-protein interaction (PPI) analysis of the target genes revealed a set of involved genes from which the hubTop 10 genes were selected for further analysis. Moreover, circRNA-miRNA-hubTop 10 mRNA networks were constructed. According to this analysis, circIFT80 simultaneously regulates hsa-miR-197-3p, hsa-miR -370-3p, and hsa-miR-377-5p, among which hsa-miR-370-3p seems to be associated with further genes that may be relevant to CRC development. Therefore, the proposed circIFT80/ hsa-miR-370-3p/WNT7B, SLC1A5, RCBTB1 and COL6A6 signal axes were subjected to experimental verification. It could be shown that circIFT80 was up-regulated in CRC tissues. The circIFT80 was able to inhibit apoptosis and promote proliferation, migration and invasion. Moreover, circIFT80 inhibited the expression of hsa-miR-370-3p and promoted the expression of COL6A6, RCBTB1, SLC1A5 and WNT7B in CRC cell lines. Dual luciferase reporter assays further validated that circIFT80 is able to bind to hsa-miR-3703p which in turn targets WNT7B. Conclusion: The circIFT80 may play a role in carcinogenesis through the new circIFT80/ hsa-miR-370-3p/WNT7B signal axis. These findings may provide potential biomarkers and therapeutic targets for the treatment of CRC.