Up-regulation of microRNA-187* inhibits proliferation of human colon cancer cell line HCT116

AIM:To investigate the expression of microRNA-187* (miR-187*) in human colon cancer cell lines and normal colon tissues, and to determine the effects of miR-187* up-regulation on the proliferation and cell cycle of human colon cancer cell line HCT116. METHODS:The expression profiling of miRNAs in 3 colorectal adenocarcinoma samples and their matched normal tissue samples was performed using miRNA microarray chip. Total RNA was isolated from 8 colon cancer cell lines and 10 normal colon tissues. The miR-187* level was detected by Taqman real-time RT-PCR. B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1), the possible target of miR-187*, was also detected. Synthetic miR-187* mimics were transfected into HCT116 cell line by LipofectamineTM 2000. The mRNA expression of miR-187* and BMI-1 in HCT116 cell line was measured by real-time RT-PCR. Cell growth and cell cycle were assayed by MTS method and flow cytometry. RESULTS:miR-187* was found to be differentially expressed between colorectal adenocarcinoma and normal tissues. The expression of miR-187* in 8 colon cancer cell lines was down-regulated, while BMI-1 mRNA was up-regulated. Compared with blank control group, miR-187* expression was remarkably increased after transfection with miR-187* mimics, and ectopic expression of miR-187* significantly inhibited the mRNA expression of BMI-1. The cell growth was inhibited in miR-187* mimics group, and proliferating cell nuclear antigen (PCNA) mRNA expression was decreased. The cells at G2/M phase in miR-187* mimics group were significantly increased. CONCLUSION: miR-187* is down-regulated in human colon cancer cell lines. Up-regulation of miR-187* not only inhibits the proliferation but also influence the cell cycle of HCT116 cells, which might act as a tumor suppressor in colorectal cancer by inhibiting the expression of BMI-1.