Açaí berries inhibit colon tumorigenesis in azoxymethane/dextran sulfate sodium-treated mice

Abstract

Background/Aims: The aim of this study was to investigate the protective effect of acai against azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colorectal cancer development. Methods: The effect of agar on tumorigenesis was assessed by evaluating tumor incidence, multiplicity and invasiveness in the mouse colon. The levels of myeloperoxidase (MPO) and proinflammatory cytokines (tumor necrosis factor alpha[TNF-alpha], interleukin [IL]-1 beta, and IL-6) were measured via enzyme-linked immunosorbent assay. Protein levels of cyclooxygenase 2 (COX-2), proliferating cell nuclear antigen (PCNA), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated death promoter (Bad) and cleaved-caspase-3 were assessed by immunoblotting. Results: Administration of pellets containing 5% acai powder reduced the incidences of both colonic adenoma and cancer (adenoma, 23.1% vs 76.9%, respectively, p=0.006; cancer, 15.4% vs 76.9%, respectively, p=0.002). In the acai-treated mice, the MPO, TNF-alpha, IL-1 beta and IL-6 levels in the colon were significantly down-regulated. Acai inhibited PCNA and Bcl-2 expression and increased Bad and cleaved-caspase-3 expression. In vitro studies demonstrated that acai treatment reduced lipopolysaccharide-induced expression of TNF-alpha, IL-6 and COX-2 in murine macrophage RAW 264.7 cells. Conclusions: Agar demonstrated protective effects against AOM/DSS-induced colon carcinogenesis, which suggests that the intake of agar may be beneficial for the prevention of human colon cancer.