Figure 7.

Carcinogen-induced IκB phosphorylation is inhibited by fisetin, luteolin, and apigenin. A) HBMEC were serum-starved for 30 minutes then treated with 1 μM PMA for the indicated time. Lysates were isolated, electrophoresed via SDS-PAGE and immunodetection of phosphorylated IκB (P-IκB) and IκB proteins was performed as described in the Materials and Methods section. B) HBMEC were serum-starved for 30 minutes in the presence of either vehicle or 30 μM fisetin, luteolin, and apigenin. Cells were then incubated for 15 minutes with 1 μM PMA. Lysates were isolated, electrophoresed via SDS-PAGE and immunodetection of phosphorylated IκB (P-IκB), IκB, and of GAPDH proteins was performed as described in the Materials and Methods section. C) Quantification was performed by scanning densitometry of the autoradiograms. Data were expressed as the percent of basal P-IκB/IκB ratios in vehicle pretreated cells. Densitometric data of a representative blot out of three is shown.

Abbreviations: HBMEC, human brain microvascular endothelial cells; PMA, phorbol 12-myristate 13-acetate; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis.