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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 4.

Figure 4

Kinetic effect of curcumin on HCT-116 cells. A, HCT-116 cells were treated with 20 µM curcumin for 0.5 to 48 h, followed by the proteasomal chymotrypsin-like activity assay using Z-GGL-AMC. B, HCT-116 cells treated with 20 µM curcumin for 6 to 48 hours were used for whole cell extract preparation. Columns, mean of representative independent triplicate experiments; bars, SD. Cell extract analyzed by Western blot confirmed proteasomal inhibition by accumulation of ubiquitinated proteins, and proteasome target proteins IκB-α, p27, and p21/Bax. Apoptosis induced by curcumin treatment was confirmed by PARP cleavage (B), caspase-3/7 activation (C), and apoptotic morphological changes (D). Actin was used as a loading control. Columns, mean of independent triplicate experiments; bars, SD. Change in the level of IκB-α, p27, p21/Bax, p36/Bax and Cyclin D1 proteins was analyzed by densitometry and quantified using AlphaEase FC software.