Effect of COX-2 gene silencing by siRNA on apoptosis and autophagy of osteosarcoma MG-63 cells

Objective: To investigate the effect of cyclooxygenase-2(COX-2) gene silencing by small interfering RNA(siRNA) on apoptosis and autophagy of osteosarcoma MG-63 cells and explore its possible mechanism. Methods: After COX-2 siRNA which targeting COX-2 gene was transfected into osteosarcoma MG-63 cells, the apoptosis was detected by fl ow cytometry(FCM), the expression levels of COX-2, Bcl-2, microtubule-associated protein 1 light chain 3(LC3) and Beclin 1 mRNAs were measured by real-time fluorogenic quantitative-PCR, and the expression levels of COX-2, Bcl-2 and Beclin 1 proteins were determined by Western blotting. Results: The expression levels of COX-2 mRNA and protein in MG-63 cells after transfection with COX-2 siRNA were lower than those in the negative control cells(MG-63 cells transfected with a control siRNA) and the blank control cells(MG-63 cells without any transfection)(P 0.05). The apoptosis rate of MG-63 cells after transfection with COX-2 siRNA was higher than that of the negative control cells and the blank control cells(P 0.05). The expression levels of anti-apoptosis factor Bcl-2 mRNA and protein in MG-63 cells after transfection with COX-2 siRNA were down-regulated(P 0.05). The expression levels of autophagy-related LC3 and Beclin 1 mRNAs and the Beclin 1 protein in MG-63 cells after transfection with COX-2 siRNA were up-regulated(P 0.05). Conclusion: Silencing of COX-2 gene may promote the apoptosis and autophagy of osteosarcoma MG-63 cells.