Evidence that de novo protein synthesis is dispensable for anti-apoptotic effects of NF-kappa B

The transcription factor NF-kappa B is a positive transcription factor for a number of genes and has been recognized as an anti-apoptotic regulator. H owever, the mechanism by which NF-kappa B blocks apoptosis is still controv ersial. Here, we demonstrate the evidence that NF-kappa B could attenuate t he TNF-alpha-induced apoptosis without de novo protein synthesis using huma n pancreatic cancer cell lines, MIA PaCa-2 and Capan-2, The TNF-alpha-induc ed apoptosis was blocked by IL-1 beta, a potent inducer of NF-kappa B activ ation. This inhibitory effect of IL-1 beta was evident when cells were trea ted with protein synthesis inhibitors such as cycloheximide (CHS). Moreover , NF-kappa B decoy oligonucleotides could not block the anti-apoptotic effe ct of IL-1 beta at doses sufficient to block the NF-kappa B-dependent trans cription induced by IL-1 beta, To confirm the role of NF-kappa B in blockin g apoptosis we generated stable cell Lines expressing I kappa B Delta N, a highly stable form of I kappa B alpha, a cytoplasmic inhibitor of NF-kappa B. In these stable transfectants, the antiapoptotic effect of IL-1 beta was totally abolished, indicating that the anti-apoptotic action of IL-1 beta could be ascribed to the NF-kappa B action. These findings show that ne nov o protein synthesis is dispensable for anti-apoptotic effects of NF-kappa B and support the possibility that NF-kappa B could exert its anti-apoptotic action through protein-protein interaction.