OBJECTIVETo explore the expression of hsa-mir-186 in colorectal cancer and study its role in regulating the biological behaviors of human colorectal cancer SW620 cells in vitro.

METHODSThe expression of hsa-miR-186 in colon cancer tissue and the adjacent tissues as well as 5 colon carcinoma cells were analyzed using real-time quantitative RT-PCR. The precursor sequence of miR-186 gene was amplified from the genomic DNA by PCR and cloned into the lentiviral vector PLVTHM labeled with GFP. The colorectal cancer cell line SW620 was transfected with PLVTHM-miR186 vector and the lentivirus-infected cells were sorted with flow cytometry. Cell counting kit-8 (CCK-8) assay was used to detect the proliferation of the cells. The migration and invasion of SW620 cells were investigated using Transwell assay and scratch test. Western blotting was used to detect the expression of YY1 protein in SW620 cell lines.

RESULTSThe relative expression of miR-186 in the cancer tissues was 0.0024∓0.0027, significantly lower than that in the adjacent tissues (0.066∓0.068, P=0.008); the relative expression level of hsa-miR-186 in SW620 and LoVo cells with a high metastatic potential was 0.118∓0.138 and 0.157∓0.001, respectively, significantly lower than that in HT-29 cells with a low metastatic potential (1.000∓0.00, P<0.05). The recombinant lentiviral vector PLVTHM-miR186, verified by enzyme digestion, sequencing and qPCR, caused significant inhibition of cell proliferation, migration and invasion and suppressed the expression of YY1 protein in SW620 cells.

CONCLUSIONAs a tumor suppressor gene, Hsa-miR-186 is down-regulated in colon carcinoma tissues and in highly metastatic SW620 and LoVo cells. Has-miR-186 can inhibit the cell proliferation, migration and invasion of colon carcinoma cells in vitro possibly by suppressing YY1 expression.