Abstract: Objective To 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. Methods The 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. Results The 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. Conclusion As 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.