Figure 6.

NF-κB and HIF-1 contribute to PGE₂ and hypoxia-induced IL-8 mRNA expression. A: Infection of endometrial epithelial cells (EP2S cells) with a dominant-negative inhibitor of NF-κB (Ad–Iκ-Bα) or control adenovirus (Ad-d1703) had no significant effect on basal IL-8 levels. B: Cells infected with Ad–Iκ-Bα demonstrated significant attenuation of PGE₂-induced IL-8 mRNA expression compared with uninfected cells or cells infected with Ad-d1703. C: Infection of cells with Ad–Iκ-Bα had no significant effect on the hypoxic induction of IL-8 expression. D: Treatment of cells with echinomycin alone for 8 hours did not significantly alter IL-8 mRNA expression. E: Concomitant treatment of cells with 100 nmol/L of PGE₂ and 5 nmol/L of echinomycin (EC), an inhibitor of HIF-1 binding, showed a significant reduction in IL-8 mRNA expression. F: Echinomycin treatment under hypoxic conditions abolished hypoxia-induced IL-8 mRNA up-regulation. G: PGE₂-induced IL-8 mRNA expression in EP2S cells was not significantly decreased by silencing of HIF-1α by shRNA. Transfection of a scrambled shRNA sequence (SCR) had no significant effect on IL-8 expression when compared with untransfected cells (n = 3). H: Hypoxic induction of IL-8 expression was significantly decreased when HIF-1α was silenced in cells before hypoxic incubation (n = 3–5). Hypoxia, 0.5% O₂; normoxia, 21% O₂; V, vehicle. *P < 0.05. **P < 0.01. ***P < 0.001).