Fig. 6.

The effect of curcumin on proliferation and cell cycle protein expression in sh-CDK2-transfected HCT116 colon cancer cells. (A) Proliferation was relatively lower in sh-CDK2-transfected HCT116 cells compared to sh-Mock-transfected HCT116 cells. HCT116 cells (1×10³ cells) were seeded in 96-well plates and after 72 h, proliferation was measured using the MTS assay as described in "Materials and Methods". (B) The effects of curcumin on cell proliferation were less in sh-CDK2-transfected HCT116 cells compared to sh-Mock-transfected cells. sh-Mock- and sh-CDK2-transfected HCT116 cells were treated with curcumin (0, 10, 20, or 40 µM) and growth was determined at 3 days using the MTS assay as described in "Materials and Methods". Data are represented as means ± S.D. as determined from 3 independent experiments. For A and B, the asterisk (*) indicates a significant difference (p < 0.001) compared to sh-Mock-transfected HCT116 cells. (C) Curcumin had no effect on cell cycle proteins in sh-CDK2-transfected HCT116 colon cancer cells. sh-Mock- and sh-CDK2-transfected HCT116 cells were treated with the indicated concentrations of curcumin for 30 min. Cell cycle protein expression was determined using specific antibodies. Data are representative of 3 independent experiments that gave similar results.