Abstract
Objective: To investigate the effects of SPAG6 silencing and decitabine on apoptosis and phosphatase and tensin homolog (PTEN) methylation in SKM-1 cells in vitro and in vivo. Methods: SKM-1 cells were transfected with a lentiviral vector to silence the expression of SPAG6. Cell survival rate was detected by CCK8 after treatment with decitabine, and cell apoptosis was detected by flow cytometry. Protein expression and methylation of PTEN were detected using Western blot and merozoite surface protein (MSP) . An non-obese diabetic/severe combined inmunodeficiency disease (NOD/SCID) mice xenograft tumor model was established, and the apoptosis and PTEN expression of tumor tissue were observed through terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and immunohistochemistry (IHC) , respectively. Results: After lentivirus transfection, SPAG6 in the interference group was silenced successfully. CCK8 results indicated that the cell survival rate of SKM-1 cells treated with decitabine decreased. Flow cytometry showed that the apoptosis rate of cells treated with decitabine [ (17.35±3.37) %] was higher than that of the untreated group (5.09%±2.06%) and the apoptosis rate of the SPAG6 silencing combined with the decitabine treatment group was the highest [ (36.34±4.00) %]. After treatment with decitabine, the expression of DNMT1 decreased, while the expression of PTEN increased, and the promoter methylation degree of PTEN also decreased. Moreover, the increased protein level caused by PTEN demethylation was the most obvious in the SPAG6 in the interference shRNA group treated with decitabine. In NOD/SCID mice, the tumor volume of the decitabine group was significantly smaller than that of the placebo group, and the tumor volume of the SPAG6 silencing combined with the decitabine treatment group was the smallest. Additionally, the apoptosis rate was the highest (the positive ratio was 3.57±0.48) . Conclusion: SPAG6 silencing may enhance the apoptosis level and the effect of PTEN demethylation in SKM-1 cells and enhance the antitumor effect of decitabine in the NOD/SCID xenograft mouse model.