[Effect of Parkinson's disease-relevant protein DJ-1 on cell proliferation, apoptosis, invasion and migration in human osteosarcoma cells].

OBJECTIVE:To investigate the effect of Parkinson's disease related protein DJ-1 on the cell proliferation, apoptosis, invasion and migration in human osteosarcoma cells and the underlying molecular mechanisms. 
 Methods: The protein expression levels of DJ-1 were detected in human osteosarcoma cell lines (MG-63, Saos-2, and U2OS) and human osteoblast cell line hFOB1.19 with or without deficiency in phosphatase and tensin homolog deleted from chromosome 10 (PTEN) were detected by Western blot. Osteosarcoma cells were treated with DJ-1 siRNA, and then the protein expression levels of DJ-1 were detected by Western blot. Cell survival rate of osteosarcoma cells was detected by cell counting kit-8 (CCK-8) assay. Cell apoptosis of osteosarcoma cells was measured by annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining method. Cell invasive and migration ability of osteosarcoma cells were examined by transwell invasion and migration assay. 
 Results: Compared with that of human osteoblast cell line (hFOB1.19), the protein expression level of DJ-1 was significantly upregulated in human osteosarcoma cell lines (MG-63, Saos-2, and U2OS) (all P<0.05), and U2OS had the highest level of DJ-1 when compared with the other three cell lines (P<0.01). DJ-1 siRNA could significantly down-regulate the DJ-1 protein expression in U2OS cells, and also diminish the cell survival rate. Moreover, DJ-1 down-regulation of DJ-1 could promote cell apoptosis, suppress the ability of cell invasion and migration, and increase the PTEN protein expression level (all P<0.05). In addition, the protein expression level of PTEN was markedly up-regulated in human osteosarcoma cell lines when compared with that in the hFOB1.19 cells (P<0.05). 
 Conclusion: DJ-1 can promote the cell proliferation, inhibit cell apoptosis, and decrease the ability of cell invasion and migration, and the potential underlying mechanisms may be associated with the up-regulation of PTEN protein expression.