Down-Regulation of miR-126 Is Associated with Colorectal Cancer Cells Proliferation, Migration and Invasion by Targeting IRS-1 via the AKT and ERK1/2 Signaling Pathways.

Zhou, Yu; Feng, Xiao; Liu, Ya-ling; Ye, Shi-cai; Wang, Hao; Tan, Wen-kai; Tian, Ting; Qiu, Yu-mei; Luo, He-sheng

Background: Colorectal carcinoma (CRC) is one of the leading causes of cancer-related mortality worldwide. MicroRNAs (miRNAs, miRs) play important roles in carcinogenesis. MiR-126 has been shown to be down-regulated in CRC. In this study, we identified the potential effects of miR-126 on some important biological properties of CRC cells and clarified the regulation of insulin receptor substrate 1 (IRS-1) and its possible signaling pathway by miR-126. Methods: The effect of miR-126 on IRS-1, AKT, and ERK1/2 expression was assessed in the CRC cell lines HT-29 and HCT-116 with a miR-126 mimic or inhibitor to increase or decrease miR-126 expression. Furthermore, the roles of miR-126 in regulation of the biological properties of CRC cells were analyzed with miR-126 mimic or inhibitor-transfected cells. The 3′-untranslated region (3′-UTR) of IRS-1 regulated by miR-126 was analyzed by using a dual-luciferase reporter assay. Results: We found that IRS-1 is the functional downstream target of miR-126 by directly targeting the 3′-UTR of IRS-1. Endogenous miR-126 and exogenous miR-126 mimic inhibited IRS-1 expression. Furthermore, gain-of-function or loss-of-function studies showed that over-expression of miR-126 down-regulated IRS-1, suppressed AKT and ERK1/2 activation, CRC cells proliferation, migration, invasion, and caused cell cycle arrest, but had no effect on cell apoptosis. Knockdown of miR-126 promoted these processes in HCT-116 cells and promoted AKT and ERK1/2 activation by up-regulating the expression of the IRS-1 protein. Conclusions: MiR-126 may play roles in regulation of the biological behavior of CRC cells, at least in part, by targeting IRS-1 via AKT and ERK1/2 signaling pathways.

GENETIC regulation; COLON cancer; CANCER cells; CELL proliferation; CELLULAR signal transduction; MICRORNA

PLoS ONE, 2013, Vol 8, Issue 11, p1

1932-6203

Academic Journal

10.1371/journal.pone.0081203