Background/aim: DNA methylation is a common epigenetic change in cancer. However, microRNA (miRNA) regulation by epigenetic alteration, especially CpG island hypermethylation, remains poorly understood in esophageal squamous cell carcinoma (ESCC).
Materials and methods: miRNAs which were up-regulated after de-methylation with 5-aza-2'-deoxycytidine (5-AZA) were analyzed using the Human miFinder 384HC miScript miRNA PCR Array. The DNA methylation level was evaluated by bisulfite-pyrosequencing assay.
Results: In two of the cell lines, 20 miRNAs, including miR-145-5p, were found to be up-regulated by more than three-fold after 5-AZA treatment. The miRNA-145 promoter was significantly more hypermethylated in the cancer tissues than in matched normal adjacent esophageal epithelial mucosa (p=0.0042; paired t-test). Moreover, the miRNA-145-5p expression levels were significantly lower in cancerous tissues (p=0.0024).
Conclusion: miRNA-145 expression in ESCC seems to be regulated by hypermethylation of the miRNA-145 promoter region.
Keywords: Cancer epigenetics; DNA methylation; esophageal squamous cell carcinoma; microRNA.
Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.