Effect of 4-trifluoromethyl derivatives of salicylate on nuclear factor kappa B-dependent transcription in human astrocytoma cells

1 The effect of two derivatives of salicylate. 2-hydroxy-4-trfluoromethylbe nzoic acid (HTB) and 2-acetoxy-4-trifluoromethylbenzoic acid (triflusal), o n the expression of several proteins displaying proinflammatory activities the regulation of which is associated to the transcription factor NF-kappaB , was assayed in the human astrocytoma cell line 1321N1. 2 Tumour necrosis factor-alpha (TNF-alpha) activated NF-kappaB as judged fr om both the appearance of kappaB-binding activity in the nuclear extracts, the degradation of I kappa -B proteins in the cell lysates, and the activat ion of I kappa -B kinases using an immunocomplex kinase assay with glutathi one S-transferase (GST)-I kappaB proteins as substrates. 3 HTB up to 3 mM did not inhibit the nuclear translocation of NK-kappaB/Rel proteins as judged from electrophoretic mobility-shift assays; however, HT B inhibited the degradation of I kappa -B beta without significantly affect ing the degradation of both I kappaB alpha and I kappaB epsilon. 4 In keeping with their inhibitory effect on Th-BP degradation in the cell lysates, both HTB and triflusal inhibited the phosphorylation of GST-I kapp aB beta elicited by TNF-alpha, without affecting the phosphorylation of GST -Ih-Ba. 5 The effect of both HTB and triflusal on kappaB-dependent trans-activation was studied by assaying the expression of both cyclo-oxygenase-2 (COX-2) a nd vascular cell adhesion molecule-1 (VCAM-1). HTB and triflusal inhibited in a dose-dependent manner the expression of COX-2 and VCAM-1 mRNA and the induction of COX-2 protein at therapeutically relevant concentrations. 6 These findings show the complexity of the biochemical mechanisms underlyi ng the activation of NF-kappaB in the different cell types acid extend the anti-inflammatory effects of HTB and triflusal to neural cells.