Comparison of the effects of the chemopreventive agent resveratrol and its synthetic analog trans 3,4,5,4′‐tetramethoxystilbene (DMU‐212) on adenoma development in the ApcMin+ mouse and cyclooxygenase‐2 in human‐derived colon cancer cells

Abstract

Naturally occurring molecules with putative cancer chemopreventive properties such as the phytoalexin resveratrol (3,5,4′‐trihydroxystilbene) are lead molecules that guide the design of novel agents with improved pharmacologic properties. The synthetic resveratrol analog 3,4,5,4′‐tetramethoxystilbene (DMU‐212) has been shown to possess stronger antiproliferative properties in human colon cancer cells than resveratrol. We tested the hypothesis that DMU‐212 is also a more potent inhibitor of adenoma development in the Apc^Min+ mouse, a model of human intestinal carcinogenesis. Apc^Min+ mice received either stilbene derivative with the diet (0.2%), and adenomas were counted after experiments were terminated. Resveratrol and DMU‐212 decreased adenoma load by 27% and 24%, respectively, compared to untreated controls. Cyclooxygenase (COX) enzymes are important mechanistic targets of resveratrol, and we investigated whether DMU‐212 interferes with the expression and activity of COX in human colon cells. Incubation of HCA‐7 cancer cells for 24–96 hr with either stilbene derivative (1–50 μM) decreased prostaglandin E‐2 (PGE‐2) production, but only resveratrol decreased COX‐2 protein expression. In mice, which received either stilbene derivative (0.2%) for 3 weeks with their diet, PGE‐2 levels in the intestinal mucosa were reduced by between 45% and 62% compared to mice on control diet. While resveratrol inhibited enzyme activity in purified COX preparations, DMU‐212 failed to do so. The PGE‐2 decrease seen with DMU‐212 in cells and in vivo is probably mediated via its metabolites. The results suggest that alteration of the resveratrol molecule to generate DMU‐212 does not abrogate its ability to decrease adenoma number in Apc^Min+ mice or to interfere with PGE‐2 generation in cells.