Abstract:
Objective To investigate the eeffect of miR-122-5p on the expression of pancreatic duodenal homeobox-1 (PDX1) on epithelial-mesenchymal transition (EMT) of colorectal cancer cells.
Methods Colorectal cancer tissue and adjacent tissue samples from 43 patients with colorectal cancer were collected. Human normal colon epithelial cell lines NCM460 and colorectal cancer cell lines HCT116, SW620 and SW480 were cultured in vitro. The expressions of miR-122-5p and PDX1 protein were detected by realtime-PCR and Western blotting. Dual-luciferase reporter gene assay was performed to measure the targeting relationship between miR-122-5p and PDX1 in SW480 cells. SW480 cells were separated into the ccontrol group, mimic NC group, miR-122-5p mimic group, miR-122-5p mimic + pcDNA3.1 group, and miR-122-5p mimic + pcDNA3.1-PDX1 group. Realtime-PCR method was performed to detect the expressions of miR-122-5p and PDX1 mRNA in SW480 cells in each group. Transwell assay and scratch assay were performed to measure the invasion and migration abilities of SW480 cells, respectively. Western blotting was performed to measure the expressionsof PDX1, matrix metalloproteinase (MMP)2, MMP9, E-cadherin and Vimentin proteins in SW480 cells.
Results The expression of miR-122-5p was lower in colorectal cancer tissues and cells, and the expression of PDX1 protein was higher (P < 0.01). The expressions of miR-122-5p and PDX1 in colorectal cancer were significantly correlated with the degree of tumor differentiation, TNM stage and lymph node metastasis (P < 0.01). There may be targeting regulatory relationship between miR-122-5p and PDX1 in SW480 cell (P < 0.01). Compared with control group, the number of invasive cells, migration rate, the expression of PDX1 mRNA and protein,MMP9, MMP2 and Vimentin protein of SW480 cells in miR-122-5p mimic group were greatly decreased (P < 0.01), while the expressions of miR-122-5p and E-cadherin protein were greatly increased (P < 0.01). Compared with miR-122-5p mimic group, the number of invasive cells, migration rate, the expression of PDX1 mRNA and protein,MMP9, MMP2 and vimentin protein of SW480 cells in miR-122-5p mimic + pcDNA3.1-PDX1 group were greatly increased (P < 0.01), while the expression of E-cadherin protein was greatly decreased (P < 0.01).
Conclusion miR-122-5p can inhibit EMT of colorectal cancer cells by targeting and inhibiting PDX1 expression, which reduces the cell invasion and migration ability.