Downregulation of microRNA-132 by DNA hypermethylation is associated with cell invasion in colorectal cancer

Abstract

Jun Qin, Jing Ke, Junfei Xu, Feiran Wang, Youlang Zhou, Yasu Jiang, Zhiwei Wang Department of General Surgery, Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, People’s Republic of China Abstract: microRNAs (miRNAs) are small, noncoding RNAs that are involved in many biological processes, and aberrant regulation of miRNAs is always associated with cancer progression and development. Abnormal expression of miRNA-132 (miR-132) has been found in some types of cancer, but the effects and potential mechanisms of miR-132 in colorectal cancer (CRC) have not been explored to date. In this study, quantitative real-time polymerase chain reaction was used to investigate the level of miR-132 in CRC tissues and their paired adjacent normal tissues. Bioinformatics analysis indicated that the mechanism underlying the tumor suppressor role of miR-132 in CRC cells may play a role in tumor suppression by targeting paxillin. Furthermore, methylation-specific polymerase chain reaction was performed to evaluate the methylation status of the miR-132 regulatory region. A DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine, was used to activate the expression of miR-132 in CRC cells in vitro. Downregulation of miR-132 may occur as a result of hypermethylation and implies a poor prognosis in CRC; therefore, triggering miR-132 reexpression by using DNA methyltransferase inhibitors may be a potential molecular therapeutic target for CRC. Keywords: microRNA-132, colorectal cancer, DNA methylation, invasion

Keywords

• microRNA-132
• colorectal cancer
• DNA methylation
• invasion