Abstract
Phenethyl isothiocyanate (PEITC) is an isothiocyanate which is a major constituent of watercress and other cruciferous vegetables. Its chemopreventive potential has been previously shown in various rodent models of cancer. In this study, we investigated the chemopreventive efficacy of PEITC in the Apc^Min/+^ mouse model. Apc^Min/+^ mice were fed with diet supplemented with 0.05% of PEITC for 3‐wk. Our results clearly demonstrated that Apc^Min/+^ mice fed with PEITC supplemented diet developed significantly less (31.7% reduction) and smaller polyps in comparison to mice fed with the standard AIN‐76A diet. Subsequent mechanistic study using Western blotting shows that inhibition of growth of adenomas by PEITC is associated with increase of apoptosis (cleaved‐caspase‐3, ‐caspase‐7, and PARP). Treatments also led to the inhibition of cell cycle‐related biomarkers such as the cyclins (D1, A, and E) and activation of p21. However, PEITC has no effect on the expression of p‐Erk, p‐JNK or p‐p38. In conclusion, our results demonstrate that PEITC is a potent natural dietary compound for chemoprevention of gastrointestinal cancers. Its mechanism of actions may include induction of apoptosis and cell cycle arrest. © 2007 Wiley‐Liss, Inc.