Effects of Curcumin on Apoptosis in SW480 Human Colon Cancer Cell Line

Curcumin, a natural compound extracted from rhizomes of Curcuma longa, has been shown to possess potent antiinflammatory and anti-tumor activity. The mechanism by which curcumin initiates apoptosis remains poorly understood. In this study, we investigated the effects of curcumin on caspase-3 activity and protein expression of procaspase-3, Bcl-2, Bax, total Akt and phosphorylated Akt in SW480 human colon cancer cell. We cultured SW480 cells in the presence of various concentrations(0, 10, 20 or 30 uM) of curcumin. Curcumin inhibited colon cancer cell growth in a dosedependent manner (p < 0.05). Caspase-3 activity was significantly increased dose-dependently in cells treated with curcumin (p < 0.05), concisely procaspase-3 expression was significantly decreased. Bcl-2 levels were decreased dosedependently in cells treated with curcumin (p < 0.05), but Bax remained unchanged. In addition, phosphorylated Akt levels and total Akt levels were markedly lower in cells treated with 20 uM of curcumin treatment (p < 0.05). In conclusion, we have shown that curcumin inhibits cell growth and induces apoptosis in SW480 human colon cancer cell lines via Akt signal pathway.

Effects of Conjugated Linoleic Acid (CLA) on Matrix Metalloproteinase (MMP) Activity and Cell Motility in Human Colon Cancer Cell Lines

Conjugated linoleic acid (CLA) consists of several geometric isomers of linoleic acid. CLA is found in foods derived from ruminants and exhibits strong anticarcinogenic effects in a variety of animal models. Matrix metalloproteinases (MMPs) play a key role in cancer progression. Specifically, MMP-2 and -9, which hydrolyze the basal membrane type IV collagen, are involved in the initial breakdown of collagen and basement membrane components during tumor growth and invasion. However, the effects of CLA on cancer cell motility and MMP expression and activity are not currently well known. Therefore, the present study examined whether CLA reduces the activity of MMP and cell motility in SW480 and SW620 cells, the human colon cancer cell lines. Gelatin zymography and Western blot analysis revealed that phorbol 12-myristate 13-acetate (PMA) induced the activity and protein expression of Mr 92,000 MMP-9 in both cell lines. To examine whether CLA inhibits the MMP activity, cells were incubated with 100 ngfmL PMA in the presence of various concentrations of CLA. PMA-induced MMP-9 activity was decreased by 20 micrometer CLA in SW480 cells, and by 10 micrometer and 20 micrometer CLA in SW620 cells. Results from the Hoyden chamber assay showed that cell motility was increased by PMA and that PMA-induced cell motility was significantly decreased by 20 micrometer CLA in SW480 cells. These results indicate that CLA may reduce the motility and MMP activity in human colon cancer cells.