Evidence for involvement of NF-kappa B in the transcriptional control of COX-2 gene expression by IL-1 beta

The cycloxygenase (COX) isoforms COX-1 and COX-2 convert arachidonic acid to prostaglandin (PG) precursors and are a limiting step in PG production, Interleukin-1 beta (IL-1 beta) treatment of type II A549 cells increases PGE(2) synthesis via transcription-and translation-dependent induction of COX-2. IL-1 beta produces a 10-fold induction of COX-2 mRNA and an 8-fold increase in COX-2 transcription that was temporally preceded by activation of the transcription factor nuclear facter-kappa B (NF-kappa B). The protein-tyrosine phosphatase inhibitor phenylarsine oxide (PAO) prevented both NF-kappa B activation and induction of COX-2 mRNA. We show that two putative NF-kappa B motifs, kappa Bu (-447/-438) and kappa Bd (-224/-214), from the COX-2 promoter bind p50/p65 NF-kappa B heterodimers in an IL-1 beta-dependent manner and that the upstream element has the greater affinity. Finally, we demonstrate that the two NF-kappa B subunits, p50 and p65, synergistically activate a -917/+49 COX-2 promoter construct, We conclude that IL-1 beta stimulates PG production via transcriptional activation of COX-2 and provide evidence that this may involve NF-kappa B. (C) 1997 Academic Press.