Abstract:

Objective To investigate the effects of microRNA-325-3p （miR-325-3p） over-expression on the invasion and migration of colon cancer cells， and to clarify their mechanisms. Methods The tumor tissue and the corresponding adjacent normal tissue of 25 patients clearly diagnosed with colon cancer were collected. The expression levels of miR-325-3p and relevant evolutionary and lymphoid interest domain containing protein 1（PRELID1） mRNA were detected by real-time fluorescence quantitative PCR （RT-qPCR） method. The expression levels of miR-325-3p and PRELID1 mRNA and the expression levels of PRELID1 protein in human normal colon cells NCM460 and colon cancer cells SW480， HCT116 and HT-29 were detected by RT-qPCR and Western blotting methods. The SW480 cells were divided into control group， NC-mimics group， miR-325-3p mimics group， miR-325-3p mimics+oe-NC group and miR-325-3p mimics+oe-PRELID1 group. The invasion and migration abilities of cells in various groups were detected by Transwell chamber assay and scratch healing assay， respectively. The expression levels of E-Cadherin， N-Cadherin and Vimentin in the epithelial-mesenchymal transition （EMT） of cells in various groups were detected by Western blotting method.The downstream target genes of miR-325-3p were predicted using the Targetscan bioinformatics website， and the targeted regulatory relationship between miR-325-3p and PRELID1 was verified by the dual-luciferase assay. Results Compared with adjacent normal tissue， the expression level of miR-325-3p in cancer tissue was significantly decreased （P<0.05）， while the expression level of PRELID1 mRNA was significantly increased （P<0.05）. The expression levels of miR-325-3p and PRELID1 mRNA was negatively correlated in colon cancer tissue （r<0， R²=0.392， P<0.001）. Compared with NCM460 cells， the expression levels of miR-325-3p in SW480， HCT116 and HT-29 cells were significantly decreased （P<0.05）， and the expression levels of PRELID1 mRNA were significantly increased （P<0.05）. Compared with control group and NC-mimics group， the number of invasive SW480 cells in miR-325-3p mimics group was significantly reduced （P<0.05）， the rate of scratch healing was decreased （P<0.05）， and the expression level of E-Cadherin protein was increased， while the expression levels of N-Cadherin and Vimentin proteins were decreased （P<0.05）. The dual-luciferase assay confirmed that PRELID1 was the direct target of miR-325-3p. Compared with miR-325-3p mimics+oe-NC group， the number of invasive SW480 cells in miR-325-3p mimics+oe-PRELID1 group was significantly increased （P<0.05）， the rate of scratch healing was increased （P<0.05）， the expression level of E-Cadherin protein was decreased， and the expression levels of N-Cadherin and Vimentin proteins were increased （P<0.05）. Conclusion Over-expression of miR-325-3p can inhibit EMT process by down-regulating PRELID1 expression， thereby inhibiting SW480 cell invasion and migration.

Key words: MicroRNA-325-3p, Relevant evolutionary and lymphoid interest domain containing protein 1, Colon neoplasm, Cell invasion, Cell migration, Epithelial-mesenchymal transition