A microarray expression profile and bioinformatic analysis of circular RNA in human esophageal carcinoma.

BACKGROUND

Recent studies indicate that non-coding circular RNAs (circRNAs) are involved in the development of esophageal carcinoma (EC). This study aimed to identify differential expression of circRNAs in EC, which can provide potential biomarkers and therapeutic targets for EC treatment and improve the understanding of tumorigenesis mechanism.

METHODS

First, samples (n=5) of EC tissues and adjacent normal tissue were sent for circRNA microarray detection, Second, further bioinformatic analysis was performed, including circRNA-microRNA (miRNA), co-expression network analysis, Spearman correlation test, and cancer-related circRNA-miRNA axis analysis. Finally, the expression of circRNA that our analysis predicted to be hub genes was verified in samples (n=15) of EC tissues and adjacent normal tissue by real-time polymerase chain reaction (RT-PCR).

RESULTS

Microarray identified 102 upregulated and 67 significantly downregulated circRNAs were in EC patients' tumors relative to adjacent normal tissue. One upregulated circRNA () showed the most connection with MREs, therefore was regarded as the hub gene by the Spearman correlation test. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that four primary pathways (mRNA surveillance, cytoskeleton actin regulation, spliceosome, and the NOD-like receptor signaling pathway) were predicted in the hub circRNA's five connected miRNA response elements (MREs). Furthermore, cancer-related circRNA-miRNA axis analyses showed that and its four connected MREs participated in the cancer-related pathway. RT-PCR showed that and were significantly increased in the tumor tissues of EC patients.

CONCLUSIONS

Abnormal expression of circRNAs was involved in the tumorigenesis of EC. Key circRNAs, namely and , may be as potential biomarkers and therapeutic targets for the treatment of EC.