FIG. 7.

Effect of ATF-2 silencing on VacA-induced COX-2 mRNA expression in AZ-521 cells. AZ-521 cells were grown overnight, and silencing of the ATF-2 gene was performed with ATF-2-siRNA or NC-siRNA as described in Materials and Methods. After a 24-h transfection, cells were suspended in EMEM without serum and treated with VacA for 2 h. (A) Reduction of the ATF-2 protein level was confirmed by Western blotting with anti-ATF-2 antibodies (upper panel), and relative densities determined by densitometry scan analysis (bottom panel) were compared to densities obtained by NC-siRNA transfection. The data are representative of at least two experiments. *, P < 0.002 compared with the control siRNA. (B) The relative levels of COX-2 mRNA expression were compared with GAPDH mRNA as measured by real-time quantitative PCR. The data are representative of at least three experiments. *, P < 0.02.