Figure 2.

Levels of IL-8 production and expression of immunoreactive IκBα protein in cultured CF and non-CF HBG cells after their exposure to genistein. ELISA assays (A) of the spontaneous (control) production of IL-8 in supernatants after 6 hours shows that the level of IL-8 release is significantly higher (a 13-fold increase) in CF HBG cells compared with non-CF HBG cells. IL-8 release was reduced as indicated in a dose- and time-dependent manner with increasing doses of genistein. Values in ELISA assays represent means ± SD of 8 ΔF508 homozygous CF HBG and 4 non-CF HBG cell cultures, respectively, with each assayed in triplicate. In CF HBG cells (B and C), treatment of cells with genistein (20 μmol/L, 16 hours) was accompanied by the de novo presence of cytosolic IκBα, as demonstrated by immunofluoresence (C), compared to untreated CF HBG cells (B). D: Equal amounts of cytoplasmic protein from non-CF gland cells (lane 1) , CF gland cells (lane 2), and genistein-treated CF gland cells (lane 3) were analyzed for levels of IκBα by Western blotting with anti-IκBα antibodies. Relative positions of size markers are shown at the left in kilodaltons. E shows densitometric analyses of the data represented in D, combined with three similar studies, expressed in arbitrary units (a.u.). Note the presence of high endogenous IκBα protein levels in (control) non-CF gland cells compared to CF gland cells. Treatment of CF gland cells with genistein (20 μmol/L, 16 hours) resulted in a significant increase of cytosolic IκBα protein, up to 80% of IκBα protein levels when compared to (control) non-CF gland cells. *, significant difference from nontreated CF gland cells (P < 0.05).