Cranberry extract and quercetin modulate the expression of cyclooxygenase-2 (COX-2) and I kappa B alpha in human colon cancer cells
BACKGROUND: Cranberry (Vaccinium marcocarpon) fruit and quercetin, a major flavonoid found in cranberries, are likely contributors to chemoprevention, and their anti-inflammatory activities may play a potential role in colon cancer prevention. The aim of this study was to examine the effect of cranberry extract and quercetin on basal expression of cyclooxygenase-2 (COX-2) and IκBα as well as the effect on phorbol 12-myristate 13-acetate (PMA)-induced COX-2 expression in colon cancer cells.
RESULTS: HT-29 human colon adenocarcinoma cells were treated with various concentrations of cranberry extract or quercetin and/or PMA, and the protein expression of COX-2 and IκBα was determined. The results indicated that cranberry extract and quercetin decreased COX-2 expression and suppressed degradation of IκBα in unstimulated cells. In PMA-stimulated cells, cranberry extract was also able to decrease COX-2 expression and suppress degradation of IκBα.
CONCLUSION: The results suggest that a possible mechanism involved in the anti-cancer activity of cranberry and quercetin is partly mediated through its anti-inflammatory action. These findings indicate that cranberry and quercetin may reduce the risk of colon cancer possibly by suppressing inflammatory responses.