Chemoprevention of intestinal adenomatous polyposis by acetyl-11-keto-beta-boswellic acid in APC(Min/+) mice.

Acetyl-11-keto-beta-boswellic acid (AKBA) is a derivative of boswellic acid, which is an active component of the gum resin of Boswellia serrata. AKBA has been used as an adjuvant medication for treatment of inflammatory diseases. In this study, we aimed to evaluate the efficacy of AKBA as a chemopreventive agent against intestinal adenomatous polyposis in the adenomatous polyposis coli multiple intestinal neoplasia (APC(Min/+) ) mouse model. APC(Min/+) mice were administered AKBA by p.o. gavage for 8 consecutive weeks. The mice were sacrificed and the number, size and histopathology of intestinal polyps were examined by light microscopy. AKBA decreased polyp numbers by 48.9% in the small intestine and 60.4% in the colon. An even greater AKBA effect was observed in preventing the malignant progression of these polyps. The number of large (>3 cm) colonic polyposis was reduced by 77.8%. Histopathologic analysis demonstrated a significant reduction in the number of dysplastic cells and in the degree of dysplasia in each polyp after AKBA treatment. There was no evidence of high grade dysplasia or intramucosal carcinoma in any of the polyps examined within the treated group. More interestingly, interdigitated normal appearing intestinal villi were observed in the polyps of the treated group. During the course of the study, AKBA was well tolerated by the mice with no obvious signs of toxicity. Results from immunohistochemical staining, Western blotting and enzyme-linked immunosorbent assay indicated that the chemopreventive effect of AKBA was attributed to a collection of activities including antiproliferation, apoptosis induction, antiangiogenesis and anti-inflammation. AKBA was found to exert its chemopreventive action through the inhibition of the Wnt/β-catenin and NF-κB/cyclooxygenase-2 signaling pathways. Our findings suggest that AKBA could be a promising regimen in chemoprevention against intestinal tumorigenesis.