Effect of dietary caraway essential oils on expression of β-catenin during 1,2-dimethylhydrazine-induced colonic carcinogenesis.

We have recently reported that the inhibition of colonic premalignant lesions induced by 1,2-dimethylhydrazine (DMH) is mediated by the interference of caraway oil components in the activities of the main hepatic xenobiotic metabolizing enzymes. The present study was carried out to examine the effect of dietary caraway oils on the progression of cancer, with emphasis on β-catenin expression in the colon during DMH-induced colonic carcinogenesis. For this purpose, colon cancer was induced by DMH in rats (20 mg/kg body weight for 5 weeks) and groups of animals were given dietary caraway essential oils at two levels (0.01 and 0.1%) for 16 weeks. After 16 weeks and at the end of the experimental period the colon tissue biopsies were processed for histopathological examination and the expression of β-catenin at mRNA and protein levels was estimated by polymerase chain reaction and enzyme-linked immunosorbent assay. The formation of premalignant lesions based on aberrant crypt foci (ACF) in DMH-treated rats was greatly inhibited (72-87%) in rats given dietary essential oils when compared to respective controls. There was a correlation between the number of colonic ACF formation and the expression levels of β-catenin measured at protein and mRNA levels. These results indicate that the Wnt/β-catenin signaling pathway is activated during colon cancer promotion and that the expression of colonic β-catenin is altered in long-term caraway oil feeding, leading to suppression of DMH-induced premalignant lesions in rat colon.