A Single Nucleotide Polymorphism (rs1056629) in 3'-UTR of MMP-9 is Responsible for a Decreased Risk of Metastatic Osteosarcoma by Compromising its Interaction with microRNA-491-5p

Background: This study aimed to explore the roles of microRNA-491-5p (miR-491) and its target MMP9 in the control of metastasis of osteosarcoma (OS) as well as how the rs1056629 polymorphism in the 3' untranslated region (3'UTR) of MMP9 compromises the interaction between miR-491 and MMP9. Methods: We used bioinformatics tools to identify possible binding sites of miR-491 in the 3'UTR of MMP9 and 30 OS tissue samples were collected and divided into two groups based on the rs1056629 genotype (AA, N=20; AC, N=8; and CC N=2). The expression of miR-491 and MMP9 were determined in those samples. Results: We found that the rs1056629 polymorphism potentially compromised the interaction between miRNA and mRNA, which was subsequently confirmed by using the luciferase reporter system. we found that the expression of miR-491 was comparable among the genotype groups, whereas the expression of MMP9 was much higher in the AC/CC groups than in the AA group. Furthermore, 10 OS cell lines (OSA, MG-63, Saos-2, U2OS, SARG, KPD, OHS, HAL, ZK-58, and MHM) were genotyped for the rs1056629 polymorphism, and MG-63 (AA) and OSA (AC) were identified for the scratch test and Transwell assay that followed. In the MG-63 cells, transfection of the miR-491 mimics and MMP9 siRNA similarly and substantially down regulated the expression of MMP9, and miRNA and siRNA clearly suppressed the migratory and invasive ability. In the OSA cells, only MMP9 siRNA notably reduced the expression of MMP9 and decreased the migratory and invasive ability. The introduction of miR-491 mimics left the expression of MMP9 and the migratory and invasive ability intact. Conclusion: We found that the rs1056629 polymorphism interfered with the interaction between MMP9 mRNA and miR-491 and is associated with the metastasis of OS cells.