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. Author manuscript; available in PMC: 2009 Sep 15.
Published in final edited form as: Cancer Res. 2008 Sep 15;68(18):7283–7292. doi: 10.1158/0008-5472.CAN-07-6246

Figure 2.

Figure 2

Inhibition of proteasomal chymotrypsin-like activity in human HCT-116 and SW480 colon cancer cells by curcumin. A, inhibition of proteasomal chymotrypsin-like activity by curcumin in intact HCT-116 and SW480 cells. HCT-116 and SW480 cells were treated with different curcumin concentrations (10, 20, and 30 µM) for 24 h, followed by measurement of proteasomal CT-like activity. Proteasome inhibitor MG132 was used as comparison with curcumin and the solvent, ethanol (E), was used as a control. B, Western blot analysis. HCT-116 and SW480 cells were treated with different curcumin concentrations (10, 20, and 30 µM) for 24 h, and used for whole cell extract preparation. Cell extract was analyzed by Western blot for accumulation of ubiquitinated proteins, IκB-α, and Bax (right and left panels). Proteasome inhibitor MG132 was used as comparison to curcumin (middle panel) and the solvent, ethanol (E), was used as a control. Actin was used as a loading control. Change in the levels of ubiquitinated IκB-α and p36/Bax proteins in the cells treated with curcumin, and the levels of ubiquitinated IκB-α and p21/Bax proteins in the cells treated with MG132 was analyzed by densitometry and quantified using AlphaEase FC software.