Plant phenolics decrease intestinal tumors in an animal model of familial adenomatous polyposis

Epidemiological studies consistently indicate that consumption of fruits an d vegetables lowers cancer risk in humans and suggest that certain dietary constituents may be effective in preventing colon cancer. Plant-derived phe nolic compounds manifest many beneficial effects and can potentially inhibi t several stages of carcinogenesis in vivo. In this study, we investigated the efficacy of several plant-derived phenolics, including caffeic acid phe nethyl ester (CAPE), curcumin, quercetin and rutin, for the prevention of t umors in C57BL/6J-Min/+ (Min/+) mice. These animals bear a germline mutatio n in the Apc gene and spontaneously develop numerous intestinal adenomas by 15 weeks of age. At a dietary level of 0.15%, CAFE decreased tumor formati on in Min/+ mice by 63%. Curcumin induced a similar tumor inhibition. Querc etin and rutin, however, both failed to alter tumor formation at dietary le vels of 2%. Examination of intestinal tissue from the treated animals showe d that tumor prevention by CAFE and curcumin was associated with increased enterocyte apoptosis and proliferation. CAFE and curcumin also decreased ex pression of the oncoprotein beta-catenin in the enterocytes of the Min/+ mo use, an observation previously associated with an antitumor effect, These d ata place the plant phenolics CAFE and curcumin among a growing list of ant i-inflammatory agents that suppress Ape-associated intestinal carcinogenesi s.