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Co‐treatment with quercetin to enhance the chemopreventive effect of green tea in prostate cancer
Author(s) -
Wang Piwen,
Henning Susanne M.,
Heber David
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.720.9
Subject(s) - lncap , chemistry , quercetin , catechin , bioavailability , pharmacology , apoptosis , prostate cancer , methyltransferase , methylation , in vivo , cancer research , biochemistry , cancer , antioxidant , polyphenol , medicine , biology , microbiology and biotechnology , gene
The low bioavailability and extensive biotransformation in vivo limit the anti‐cancer potential of green tea polyphenols such as (−)‐epigallocatechin‐3‐gallate (EGCG). We found that fifty percent or more of EGCG was present in methylated form (4″‐O‐methyl EGCG) in human prostate tissue after drinking 6 cups of green tea daily and in mouse xenograft prostate tumors after consuming green tea in drinking water. In LNCaP prostate cancer cells, incubated with EGCG, 50% was found in form of 4″‐O‐methyl EGCG. Since EGCG methylation significantly decreased the activity of EGCG to inhibit proliferation and NFkB stimulation, and to induce apoptosis in LNCaP cells, we investigated whether co‐treatment of EGCG with quercetin will decrease EGCG methylation. Co‐treatment of LNCaP cells with quercetin, a natural inhibitor of both multidrug resistance proteins and catechol‐O‐methyltransferase (COMT), increased the absorption of EGCG 10‐fold in a dose‐dependent manner as well as significantly reduced the methylation of intracellular EGCG by 50%. The co‐treatment exhibited a stronger inhibitory effect on mRNA expression of DNA methyltransferase 1 and COMT compared to EGCG treatment alone. These results support our hypothesis that co‐treatment of EGCG with quercetin decreased EGCG methylation which may increase the chemopreventive effect of green tea. This research was supported by RO1 CA116242.