Novel shift of Jak/Stat signalling characterizes the protective effect of aurintricarboxylic acid (ATA) from tumor necrosis factor-α toxicity in human B lymphocytes

Previous results demonstrated that the occurrence of death in human peripheral B lymphocytes by TNF-a was paralleled by the activation of the cytoplasmic Jak1 and Tyk2 protein kinases, along with the recruitment of transcription factors Stat3 and Stat5b. In this study we demonstrate that the balance of survival signals in the presence of TNF-alpha was altered by the addition of a salicylate compound, the endonuclease inhibitor aurintricarboxylic acid (ATA). Apoptosis effected by TNF-alpha alone was suppressed by ATA and this event was paralleled by phosphorylation and nuclear translocation of Jak2, Stat2, Stat4 and NF-kB, along with inhibition of caspase activation. These results confirm that among the different cellular responses evoked by TNF-alpha in human B cells, recruitment of Jak/Stat proteins and possible related gene modulation represent contributing factors and address the issue of the development of potential therapeutic strategies aimed at the control of systemic or local effects produced by TNF-alpha.