MicroRNA-766 targeting regulation of SOX6 expression promoted cell proliferation of human colorectal cancer

Yong-chao Li,1 Chang-feng Li,2 Li-bo Chen,2 Dan-dan Li,2 Lei Yang,2 Jing-peng Jin,2 Bin Zhang21Department of Gastrointestinal Surgery, 2Department of Endoscopy Center, China–Japan Union Hospital of Jilin University, Changchun, People’s Republic of China Abstract: MicroRNAs (miRNAs) have emerged as important regulators of cancer-cell biological processes. Previous studies have shown that miR-766 plays an important role in a variety of biological processes in various human cancers. However, the underlying mechanism of miR-766 in colorectal cancer (CRC) cells remains unclear. In this study, we investigated miR-766’s role in CRC cell proliferation. Polymerase chain reaction results showed that miR-766 expression was significantly upregulated in CRC tissues and cells. Ectopic expression of miR-766 promoted cell growth and anchorage-independent growth in CRC cells. Bioinformatic analysis predicted SOX6, a potential target of miR-766, acting as a tumor suppressor. Luciferase reporter assay results demonstrated that miR-766 directly bound to the 3'-untranslated region of SOX6. Overexpression of miR-766 suppressed SOX6 expression, resulting in the downregulation of p21 and upregulation of cyclin D1. In a further experiment, SOX6-silenced SW480 cells transfected with miR-766 promoted cell growth, suggesting that downregulation of SOX6 was required for miR-766-induced CRC cell proliferation. Taken together, these results suggested that miR-766 represents an onco-miRNA and participates in the development of CRC by modulating SOX6 expression. Keywords: miR-766, colorectal cancer, SOX6, cell proliferation