Demethylation-mediated miR-129-5p up-regulation inhibits malignant phenotype of osteogenic osteosarcoma by targeting Homo sapiens valosin-containing protein (VCP).

Previous studies demonstrated that increased Homo sapiens valosin-containing protein (VCP) may be involved in osteosarcoma (OS) metastasis. However, the underlying mechanism of VCP over-expression in OS remains unknown. In the present study, we found a significantly negative correlation between miR-129-5p and VCP protein expression in OS tissues with pulmonary metastasis (Spearman's rho, rs = -0.948). Bioinformatical prediction, Luciferase reporter assay, Western blot, and RT-PCR assays performed on OS cells indicated that VCP is a target of miR-129-5p. In addition, three CPG islands in the region of miR-129-5p promoter were detected by bioinformatical prediction, and significantly higher expression of miR-129-5p and lower methylation level of miR-129-2 gene in OS cells treated with 5-Aza-2'-deoxycytidine (a potent DNA demethylating agent) than in those untreated cells were observed. Furthermore, lower migratory and invasive ability was found in cells with elevated miR-129-5p than in those with decreased miR-129-5p. These findings indicated that increased miR-129-5p may be mediated by demethylation and inhibit OS cell migration and invasion by targeting VCP in OS, and targeting miR-129-5p/VCP signaling pathway may serve as a therapeutic strategy for OS management, although further studies will be necessary.