A miRNAs panel promotes the proliferation and invasion ofcolorectal cancer cells by targeting GABBR1

MicroRNAs (miRNAs) have been implicated in the regulation of colorectal cancer. Despite the expression of miR-17-92 cluster in cancer has been gradually revealed, the role of each individual miRNAs in colorectal cancer still remains unclear. We studied the impact of miR-106a/b, miR-20a/b, and miR-17 of miR-17-92 cluster on colorectal cancer cells. Real-time quantitative polymerase chain reactions (RT-PCR) were used to test these five miRNAs expression in colorectal cancer cell line HCT116. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assays, Bromodeoxyuridine (BrdU), and Transwell invasion assays were used to explore the effects of these five miRNAs in colorectal cancer cells. Luciferase reporter assay, RT-PCR, and western blotting were performed to validate the interaction of these five miRNAs with the gamma-amino-butyric acid type B receptor 1(GABBR1). We found that these five miRNAs were significantly upregulated in colorectal cancer samples compared with normal tissues. Forced expression of these five miRNAs significantly promoted HCT116 and HT-29 cells proliferation and invasion. We further found that these five miRNAs function as oncogenes in colorectal cancer by specifically binding to the 3-untranslated regions (3UTR) of GABBR1.Furthermore, inhibition of GABBR1 could mimic the function of miRNAs in HCT116 cells, while overexpression of GABBR1 blocked the function of miRNAs-promoted proliferation and invasion. In conclusion, miR-106a/b, miR-20a/b, and miR-17 contribute to the proliferation and invasion of colorectal cancer by targeting their common target gene, GABBR1, and played a critical role in the proliferation and invasion of colorectal cancer.