Investigating the expression of hsa_circ_0036722/hsa-miR-503-5p/PDCD4 axis in esophageal cancer

Esophageal cancer (EC) is the ninth most common cancer globally. Circular RNAs (circRNAs), including hsa_circ_0036722, are important in various cancers, but their specific role in EC remains unclear. Therefore, this study investigates the roles of hsa_circ_0036722 in EC.

We analyzed circRNAs sequencing from Gene Expression Omnibus (GEO). On the other hand, analyzed miRNAs and mRNAs sequencing related to EC from The Cancer Genome Atlas (TCGA). Then, the hsa_circ_0036722/hsa-mir-503-5p/PDCD4 axis was identified using online tools for detecting circRNA-associated miRNAs and target mRNAs. Gene expression levels in 20 EC tissue pairs were assessed using RT-qPCR, while PDCD4 protein expression was evaluated by Western blot. A receiver operating characteristic (ROC) analysis was performed to evaluate their diagnostic potential.

RT-qPCR results demonstrated decreased expression of hsa_circ_0036722 and PDCD4, alongside increased hsa-miR-503-5p expression in EC tissues. A reduction in PDCD4 protein expression was also noted. Correlations showed that hsa_circ_0036722 and PDCD4 expressions were positively correlated, while hsa_circ_0036722 and hsa-miR-503-5p were negatively correlated. In addition, a significant negative correlation was observed between hsa-miR-503-5p and PDCD4 expression. Elevated levels of hsa-miR-503-5p were detected in early stages of EC. The ROC curve reflected a significant area under the curve for the axis genes.

This study identified a novel regulatory axis, hsa_circ_0036722/hsa-mir-503-5p/PDCD4, for regulating EC, which may be a potential target for treating patients with this cancer.