Esophageal squamous cell carcinoma (ESCC) is one of the most common and deadly cancers in the world. Currently, clinical therapy of ESCC remains limited and the five-year survival rate is poor. The function of miR-425 has been reported in multiple human cancers. However, the tumorigenic role and clinical significance of miR-425 in ESCC remains unclear. We found that enhanced expression of miR-425 in ESCC cell lines not only promoted cell proliferation and colony formation, but also increased cellular metastasis. Furthermore, we revealed the mechanism that miR-425 inhibited the expression of SMAD2 by targeting the second binding site in the 3'-untranslated region (3'-UTR) in ESCC. This mode of action influenced not only SMAD2 mRNA expression but also protein expression. In addition, we detected the expression of miR-425 in ESCC tissues and plasma. Moreover, we analyzed the relationship between miR-425 expression and SMAD2 mRNA expression. We found that miR-425 was overexpressed in ESCC tissues and the plasma relative to adjacent normal tissues and plasma of healthy individuals. Furthermore, there was a negative correlation between miR-425 expression and SMAD2. Taken together, our results show that miR-425 functions as an oncogene by targeting the 3'-UTR of SMAD2 and indicate the potential utility of plasma miR-425 as a novel biomarker for ESCC diagnosis.
Keywords: Esophageal squamous cell carcinoma; Plasma miRNA; SMAD2; miR-425.
Copyright © 2015 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.