Figure 9. ROS-sensitized cells lack NF-κB activation.

(A) HeLa cells were pre-treated with 500 nM H₂O₂ (lower panels) or left untreated (upper panels). After 8 h, cells were washed and culture medium was replaced. Cells then were treated with the indicated concentrations of H₂O₂ for 16 h, and photographed (phase-contrast, 10×). (B) HeLa cells were pre-treated with 500 nM H₂O₂ or left untreated (control). After 8 h, cells were washed and treated with the indicated concentrations of H₂O₂ for 10 min. IKKγ was immunoprecipitated, and an IKK assay was performed using GST–IκBα as substrate (upper panel). Expression of IKK was determined by immunoblotting with anti-IKKα/β antibody (lower panel).