Selenium: a key element that controls NF-kappa B activation and I kappa B alpha half life.

Treatment of mammalian cells with hydrogen peroxide induces the nuclear translocation of the transcription factor NF-kappa B and its binding to kappa B DNA sequences present in the promoter region of numerous genes. The role of selenium in NF-kappa B activation was analyzed in human T47D cells overexpressing the seleno-dependent detoxifiant enzyme glutathione peroxidase. Following exposure to H(2)O(2), these cells showed a seleno-dependent decreased accumulation of intracellular ROS and NF-kappa B activation. This phenomenon was correlated with an inhibition of the nuclear translocation of NF-kappa B (p50 subunit) and with an absence of I kappa B alpha degradation. We also report that the half-life of I kappa B alpha in untreated cells was increased two-fold by the overexpression of active glutathione peroxidase. These results suggest that selenium is a key element that through its modulation of glutathione peroxidase activity can inhibit NF-kappa B activation and can up-regulate I kappa B alpha normal half life.