BACKGROUND: Peroxynitrite has been proposed to activate Nuclear Factor κappa beta (NF-κB) in a non-canonical or aberrant pathway and to contribute to pathology of many diseases. METHODS: The activation of NF-κB by peroxynitrite was assessed by Western blot, immunoprecipitation, RT-PCR, and image stream analysis. RESULTS: Our work showed that in HT-29 cancer cells, peroxynitrite can cause nitration of Inhibitory protein kappa B alpha (IκBα) at the expense of its phosphorylation. This led to a decrease in the degradation and re-synthesis of IκBα. Similar findings were observed for mRNA levels assessed by RT-PCR. Exposure of HT-29 cells to p38 inhibitor SB202190, prior to stimulation, resulted in a dramatic decrease of IκBα kinase and IκBα phosphorylation and caused an increase of peroxynitrite-mediated nitration of IκBα, indicating that peroxynitrite may activate NF-κB via dual mechanism of IκBα phosphorylation which is p38 dependent, as well as IκBα nitration. CONCLUSION: Our findings demonstrate a possible interaction of the p38 pathway with the NF-κB pathway under peroxynitrite stimulation.
BACKGROUND:Peroxynitrite has been proposed to activate Nuclear Factor κappa beta (NF-κB) in a non-canonical or aberrant pathway and to contribute to pathology of many diseases. METHODS: The activation of NF-κB by peroxynitrite was assessed by Western blot, immunoprecipitation, RT-PCR, and image stream analysis. RESULTS: Our work showed that in HT-29 cancer cells, peroxynitrite can cause nitration of Inhibitory protein kappa B alpha (IκBα) at the expense of its phosphorylation. This led to a decrease in the degradation and re-synthesis of IκBα. Similar findings were observed for mRNA levels assessed by RT-PCR. Exposure of HT-29 cells to p38 inhibitor SB202190, prior to stimulation, resulted in a dramatic decrease of IκBα kinase and IκBα phosphorylation and caused an increase of peroxynitrite-mediated nitration of IκBα, indicating that peroxynitrite may activate NF-κB via dual mechanism of IκBα phosphorylation which is p38 dependent, as well as IκBα nitration. CONCLUSION: Our findings demonstrate a possible interaction of the p38 pathway with the NF-κB pathway under peroxynitrite stimulation.
Authors: Nieves González; Isabel Prieto; Laura Del Puerto-Nevado; Sergio Portal-Nuñez; Juan Antonio Ardura; Marta Corton; Beatriz Fernández-Fernández; Oscar Aguilera; Carmen Gomez-Guerrero; Sebastián Mas; Juan Antonio Moreno; Marta Ruiz-Ortega; Ana Belen Sanz; Maria Dolores Sanchez-Niño; Federico Rojo; Fernando Vivanco; Pedro Esbrit; Carmen Ayuso; Gloria Alvarez-Llamas; Jesús Egido; Jesús García-Foncillas; Alberto Ortiz Journal: Oncotarget Date: 2017-03-14