MicroRNA-30a Inhibits Colorectal Cancer Metastasis Through Down-Regulation of Type I Insulin-Like Growth Factor Receptor

Background: miR-30a expression is down-regulated and regulates tumor suppressors in various cancers. Aim: We investigated the mechanisms underlying the biological role of miR-30a in CRC. Methods: MicroRNA, mRNA, and protein expression were analyzed by quantitative real-time PCR and Western blot. The migration and invasion abilities of CRC were determined by wound healing assay, and trans-well migration and invasion. A luciferase reporter assay was used to confirm the targets of miR-30a. Results: miR-30a expression was significantly down-regulated in CRC tissues and in CRC tissue with lymph node metastasis compared to CRC tissue without metastasis. Overexpression of miR-30a suppressed migration and invasion through insulin-like growth factor 1 receptor (IGF1R) in CRC cells. miR-30a suppresses IGF1R protein expression and inhibits β-catenin or p-AKT and increases E-cadherin expression. The IGF1R expression level is also up-regulated in CRC tumors and inversely correlated with miR-30a in CRC specimens. Conclusions: miR-30a functions as a tumor-suppressive miRNA, which may provide a therapeutic strategy for metastasis of CRC.