Effect of curcumin on NF-κB–regulated gene products.
First, 2 × 106 U266 cells were treated with curcumin (50 μM) for the indicated times, and cytoplasmic extracts were prepared. (A-D) Then, 60 μg cytoplasmic extracts were resolved on 10% SDS-PAGE gel, electrotransferred on a nitrocellulose membrane, and probed for the following: IκBα (panel A); Bcl-2 (panel B); Bcl-xL (panel C); and cyclin D1 (panel D). The same blots were stripped and reprobed with anti–β-actin antibody to show equal protein loading (lower panels). (E) Curcumin down-regulates IL-6 production. U266, MM.1, or RPMI 8226 cells (2 × 106/mL) were treated with curcumin (10 μM); supernatants were harvested after 24 hours, and levels of IL-6 were assayed by IL-6 ELISA kit as described in “Materials and methods.” Values are mean IL-6 levels (error bars indicate standard deviations SDs) obtained from 3 independent treatments of cell with curcumin.
