Regulation of IL-1β induction of COX-2 protein in human lung fibroblasts by the AhR is at the level of mRNA stability.

(A) HLFs- AhR siRNA: There was significantly more Cox-2 mRNA remaining after induction with IL-1β in AhR knock-down cells. (B) A549-AhR^KO: There was a significant decline in the percentage (%) of Cox-2 mRNA remaining within one hour after addition of ActD in A549-AhR^WT cells (* p < 0.05; ** p< 0.01) but not in A549-AhR^KO cells (ns). Results are expressed as mean ± SEM of 2 independent experiments.