NUTRITION AND CANCER, 59(1), 62–69 Copyright C  2007, Lawrence Erlbaum Associates, Inc. Inhibition of Intestinal Tumorigenesis in Apc Min/+ Mice by Green Tea Polyphenols (Polyphenon E) and Individual Catechins Xingpei Hao, Mousumi Bose, Joshua D. Lambert, Jihyeung Ju, Gang Lu, Mao-Jung Lee, Sunny Park, Ali Husain, Steven Wang, Yuhai Sun, and Chung S. Yang Abstract: In this work, we compared the cancer preven- tive activities of Polyphenon E (PPE), a standardized green tea polyphenol preparation given in diet versus drinking fluid as well as the activities of PPE versus individual cat- echins. We treated Apc Min/+ mice for 9 wk with 0.08% (-)- epigallocatechin-3-gallate (EGCG), 0.08% (-)-epicatechin- 3-gallate, or 0.12% PPE in drinking fluid or diet. Only 0.12% dietary PPE and 0.08% EGCG in drinking fluid significantly decreased tumor multiplicity (70% and 51%, respectively). Compared to PPE in drinking fluid, dietary PPE delivered twofold more EGCG to the small intestine. Immunohisto- chemistry showed that adenomas in groups treated with PPE and EGCG had decreased cell proliferation, β -catenin nu- clear expression, and phospho-Akt levels; higher cleaved caspase-3 levels, and partially restored retinoid X receptor α expression. The results suggest that these molecular events contribute to the cancer prevention activity of EGCG and PPE. Furthermore, diet appears to be a better route of ad- ministration for PPE than drinking fluid. Introduction Green tea, made from the dried leaves of the plant Camel- lia sinensis, has been studied extensively for possible cancer preventive effects. The most abundant and biologically ac- tive tea polyphenol is (-)-epigallocatechin-3-gallate (EGCG). Other catechins such as (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC), and (-)-epicatechin (EC) may also contribute to the biological activities of green tea. The possible inhibitory effects of green tea extracts and related polyphenols have been studied in different rat models using colon tumor or aberrant crypt foci (ACF) formation as endpoints, but the results are not conclusive; inhibitory effects (1,2), marginal inhibitory effects (3,4), and lack of an inhibitory effect (5–8) have been reported. On the other hand, the inhibitory activities of green tea and tea polyphenols have All authors are affiliated with the Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854. been consistently demonstrated in mouse models [reviewed in (9,10)]. Green tea extracts, alone and in combination with sulindac, have been shown to decrease intestinal tumor for- mation in the Apc Min/+ mouse model (11,12). We have sys- tematically investigated the effect of EGCG on intestinal tumorigenesis in Apc Min/+ mice and found that oral admin- istration of EGCG (0.08–0.32% in drinking fluid) inhibited tumorigenesis (13). Oral administration of green tea extracts or EGCG has also been shown to inhibit the formation of azoxymethane (AOM)-induced ACF and colon tumor for- mation in mice [(14) and unpublished results]. In theory, the intestine is a promising site for chemopre- vention with polyphenols that have low systemic bioavail- ability. EGCG, the major polyphenol in green tea, has only limited systemic bioavailability after oral ingestion; even the absorbed EGCG is excreted mostly into the intestine through the bile (9). Therefore, the intestine may actually be exposed to high levels of EGCG after ingestion. The reasons for the inconsistency among the different studies are complex and may be related to several factors: 1) the animal species used, 2) the diet used, 3) the protocol of tumor initiation and tu- mor yield, and 4) the type and dose of tea polyphenols or extracts used, when they were given, and whether they were administered through drinking fluid or through the diet. Polyphenon E (PPE) is a standardized green tea polyphe- nol preparation containing about 65% EGCG and 25% other catechins. It has high potential for use in human cancer pre- vention trial; extensive studies on toxicology and pharma- cokinetics have been conducted (14,15). This work was ini- tiated to compare the inhibitory activities of PPE when given in the drinking fluid versus in the diet as well as the activi- ties of PPE versus individual catechins, EGCG and ECG, in the Apc Min/+ mice. ECG was included in the study because of the proposal that ECG may be a more active preven- tive agent than EGCG due to its higher activity in inducing nonsteroidal anti-inflammatory drug (NSAID) activated gene (NAG-1) (16).