RESUMO
Objective: To investigate the effect of inhibitor of differentiation 1 (Id 1) gene on apoptosis of human osteosarcoma MG63 cells, and to explore its possible molecular mechanism. Methods: The specific siRNA targeting Id 1 gene (Id1-siRNA) was infected into MG63 cells using recombinant adenovirus Ad-siRNA-Id1 as the AdsiId1 group, while the negative control group (infection with the empty vector adenovirus AdRFP) and the blank control group (non-infection) were set up, respectively. The expression levels of Id1 mRNA and protein were detected by semi-quantitative RT-PCR and Western blotting, respectively. The apoptosis of MG63 cells was detected by Annexin V-FITC staining and DAPI staining. The cell cycle distribution of MG63 cells was detected by FCM method. The expression levels of apoptosis-related proteins (Bcl-2 and survivin) and Wnt pathway-related proteins [β-catenin, receptor tyrosine kinase-like orphan receptor 2 (ROR2) and CCAAT/enhancer-binding protein homologous protein (CHOP)] were detected by Western blotting. Results: After infection with recombinant adenovirus Ad-siRNA-Id1, the expression levels of Id1 mRNA and protein in MG63 cells were significantly decreased (both P < 0.05). The apoptotic rate in AdsiId1 group was higher than those in AdRFP and the blank control groups (both P < 0.05). The expression levels of Bcl-2 and survivin mRNAs and proteins were significantly decreased (all P < 0.05). The expressions of β-catenin, ROR2 and CHOP proteins were also significantly decreased (all P < 0.05). Conclusion: The silencing of Id 1 gene expression can promote the apoptosis of osteosarcoma cells, which may be related to regulating Wnt signaling pathway.