miR-145 suppresses colorectal cancer cell migration and invasion by targeting an ETS-related gene

Abstract MicroRNA-45 (miR-145) has been demonstrated to be downregulated in various cancer types including colorectal cancer (CRC). However, the function of miR‑145 in CRC has not been clearly elucidated. In this study, we examined miR-145 expression by quantitative real‑time PCR (qRT‑PCR) in CRC cell lines as well as tumors and corresponding normal mucosa, and the results were correlated to the clinicopathological parameters. In addition, using computational algorithms we investigated putative miR‑145 targets. The role of miR‑145 was further examined in studies in vitro. In our study miR‑145 was significantly decreased in CRC tissues and cell lines compared with non‑cancerous colorectal mucosa, especially lymph node or distance metastasis cases. Based on computational algorithms, we assumed that ERG was directly modulated by miR‑145 in colorectal cancer cells. For the first time, we demonstrated that ERG was highly expressed in CRC tissues compared with normal ones by qRT‑PCR. The inverse correlation between the expression of miR‑145 and ERG was observed in CRC tissues. Dual‑Luciferase assays demonstrated the direct interaction between miR‑145 and 3'‑UTR of ERG mRNA. Ectopic expression of miR‑145 suppressed the proliferation and invasion ability of colorectal cancer cells, while ERG knockdown partially restored the tumor suppressive effect of miR‑145. These results suggested that miR‑145 might act as a tumor suppressor during the process of CRC malignant transformation by interacting with ERG.