Metabolites of intestinal microflora upregulate miR-192-5p to suppress proliferation of colon cancer cells via RhoA-ROCK-LIMK2 pathway

OBJECTIVE The application of intestinal microflora is involved in various cancers; however, researches reporting the potential of metabolites of intestinal microflora (MIM) on biological activities of colon cancer (CC) cells are unavailable. This study was designed to testify the functions of MIM on CC cells and its mechanism. MATERIALS AND METHODS qRT-PCR/Western blot were applied to test the expression levels of miR-192-5p and BMPR2 in human colonic epithelial cells and CC cells (HCT116, SW480). The effects of MIM, mimics-miR-192-5p or inhibitors-miR-192-5p on mRNA and protein expressions of miR-192-5p and BMPR2 were verified by qRT-PCR and Western blot. MTT assay for CC cell viability, flow cytometry for CC cells apoptosis rate, and cell scratch and cell chamber served for the analysis of invasion and migration ability of CC cells. The relationship between miR-192-5p and BMPR2 was validated employing Luciferase reporter gene assay. RESULTS Compared with human normal colonic epithelial cells, HCT116 and SW480 cells had lower expression of miR-192-5p and higher expression of BMPR2 (p < 0.01). MIM and mimics-miR-192-5p could enhance cell apoptosis and suppress the migration and proliferation of CC cells. MIM were also found to up-regulate miR-192-5p and down-regulate the expression levels of BMPR2 and p-LIMK2 (p < 0.01). Transfection of inhibitors-miR-192-5p reversed the inhibitory effect of MIM on CC cells. CONCLUSIONS MIM could up-regulate miR-192-5p to inhibit CC cell growth via down-regulating BMPR2 and inhibiting the activity of RhoA-ROCK-LIMK2 pathway.