Effects of oxidants and antioxidants on nuclear factor kappa B activation in three different cell lines: evidence against a universal hypothesis involving oxygen radicals

Abstract

A model for NF kappa B activation involving reactive oxygen intermediates has recently been proposed. We have explored this model in three cell lines, Jurkat T cells, EL4.NOB-1 T cells and KB epidermal cells using hydrogen peroxide and two physiological activators of NF kappa B, interleukin-1 (IL1) and tumor necrosis factor (TNF) as stimuli. In agreement with earlier studies hydrogen peroxide activated NF kappa B in Jurkat, although only at much higher concentrations (10 mM) than those previously reported. However, hydrogen peroxide failed to activate in the two other cell lines under a range of conditions. Similarly, N-acetylcysteine only proved inhibitory in hydrogen peroxide and TNF treated Jurkat and failed to inhibit IL1 and TNF-activated NF kappa B in EL4.NOB-1 and KB cells respectively. N-Acetylcysteine inhibited IL1-induced interleukin-2 in EL4, however, demonstrating that N-acetylcysteine was biologically active. These results suggest that the reactive oxygen model of NF kappa B activation may be cell-type restricted. In contrast to the results with N-acetylcysteine, the antioxidant and metal chelator, pyrolidine dithiocarbamate (PDTC) inhibited NF kappa B activation, although these effects may be unrelated to any antioxidant properties. PDTC also inhibited IL1-induced interleukin-2. Finally, studies with the pro-oxidant diamide showed that this could not activate NF kappa B in any of the cells and in contrast proved inhibitory. The results from this study therefore suggest that the reactive oxygen model of NF kappa B activation may be restricted to certain cell types and that the presence of such a system is not required for the activation of NF kappa B by IL1 and TNF.