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Nonsteroidal anti-inflammatory drug-activated gene (NAG-1) is induced by genistein through the expression of p53 in colorectal cancer cells.
Authors: Wilson LC, Baek SJ, Call A, Eling TE.
Source: Int J Cancer. 2003 Jul 20;105(6):747-753.
Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
Genistein is an isoflavenoid found in soy that has anti-tumorigenic activities. Treatment of colorectal carcinoma HCT-116 cells with 50 &mgr;M genistein results in a 50% reduction in cell proliferation and a 6-fold increase in apoptosis. Genistein induces nonsteroidal anti-inflammatory drug-activated gene 1 (NAG-1), a protein with antitumorigenic activities, in a time- and concentration-dependent manner in HCT-116 cells. In addition, p53 and p21 are induced in HCT-116 cells. The induction of p53 (3 hr) precedes the induction of NAG-1 (12 hr), suggesting that genistein-induced NAG-1 expression is mediated by p53. In contrast, NAG-1 is not induced by genistein in the p53-negative colorectal carcinoma cell line HCT-15. Luciferase reporter constructs of the NAG-1 promoter containing 2 p53 sites showed that the p53 sites within the NAG-1 promoter are critical to genistein-induced NAG-1 expression in p53-positive U2OS cells. The expression of p53 was critical for NAG-1 promoter activity since no promoter activity was observed with genistein treatment in HCT-15 cells. However, genistein-induced promoter activity was restored in HCT-15 cells by transfection with wild-type p53. Together our data suggest a relationship between genistein, p53 and NAG-1 forming a novel pathway responsible for the antitumorigenic activity of genistein. Copyright 2003 Wiley-Liss, Inc.