Transcription-based COX-2 inhibition: a therapeutic strategy.

Potent selective cyclooxygenase-2 (COX-2) inhibitors are effective in controlling inflammatory disorders but are associated with cardiovascular complications. Their clinical use has been severely limited. We propose that transcription-based inhibition of COX-2 expression represents a therapeutic strategy that may circumvent the undesired complications of COX-2 inhibitors. Reported data from several laboratories including ours have identified C/EBPbeta as a key transactivator mediating COX-2 transcriptional activation induced by diverse pro-inflammatory mediators. Results from our recent work show that sodium salicylate at pharmacological concentrations inhibits C/EBPbeta binding to COX-2 promoter by direct inhibition of p90 ribosomal S6 kinase (RSK). RSK phosphorylates C/EBPbeta and stimulates its binding to enhancer elements. We propose that RSK1/2 is a potential target for screening drugs with novel anti-inflammatory and anti-neoplastic therapeutic potentials.