Figure 4.

Effect of Sp1 RNA interference on gliostatin (GLS) expression. Western blotting analysis shows that Sp1 small interfering RNA (siRNA) (20 nM) transfection for 48 hours strikingly blocked Sp1 expression compared with negative control (NC) siRNA (20 nM) transfection (A). After Sp1 or NC siRNA transfection for 24 hours, cells were treated with tumor necrosis factor-alpha (TNF-α) (1 ng/mL) for 24 hours. GLS mRNA expression levels are presented as mean ± standard error of the mean of five determinations (B). GLS mRNA levels are represented relative to β-actin. Statistical significance was calculated by using the Mann-Whitney U test: compared with NC siRNA samples *P < 0.01; compared with NC siRNA samples with TNF-α ^†P < 0.01.