Volume 49, Issue 1 p. 36-45
Research Article
Free Access

Modulation of gene methylation by genistein or lycopene in breast cancer cells

Audrey King-Batoon

Audrey King-Batoon

The Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, New York

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Joanna M. Leszczynska

Joanna M. Leszczynska

The Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, New York

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Catherine B. Klein

Corresponding Author

Catherine B. Klein

The Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, New York

The Nelson Institute of Environmental Medicine, New York University School of Medicine, 57 Old Forge Road, Tuxedo, New York 10987, USASearch for more papers by this author
First published: 07 January 2008
Citations: 179

Abstract

Dietary agents with chemopreventive potential, including soy-derived genistein and tomato-derived lycopene, have been shown to alter gene expression in ways that can either promote or potentially inhibit the carcinogenic processes. To begin to explore the mechanisms by which these agents may be acting we have examined the DNA methylation modulating capacity of genistein or lycopene for several genes relevant to breast cancer in the breast cancer cell lines MCF-7 and MDA-MB-468, as well as in immortalized but noncancer fibrocystic MCF10A breast cells. We find using methylation specific PCR (MSP) that a low, nontoxic concentration of genistein (3.125 μM, resupplemented every 48 hr for 1 week) or a single dose of lycopene (2 μM) partially demethylates the promoter of the GSTP1 tumor suppressor gene in MDA-MB-468 cells. RT-PCR studies confirm a lack of GSTP1 expression in untreated MDA-MB-468, with restoration of GSTP1 expression after genistein or lycopene treatment. The RARβ2 gene however, was not demethylated by genistein or lycopene in either of these breast cancer cell lines. But, lycopene (2 μM, once per week for 2 weeks) did induce demethylation of RARβ2 and the HIN-1 genes in the noncancer MCF10A fibrocystic breast cells. These data show for the first time that the tomato carotenoid lycopene has direct DNA demethylating activity. In summary, both genistein and lycopene, at very low, dietarily relevant concentrations can potentially mitigate tumorigenic processes via promoter methylation modulation of gene expression. Environ. Mol. Mutagen., 2008. © 2008 Wiley-Liss, Inc.

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