Suppression of β-catenin and Cyclooxygenase-2 Expression and Cell Proliferation in Azoxymethane-Induced Colonic Cancer in Rats by Rice Bran Phytic Acid (PA)


Background: Phytic acid (PA) is a polyphosphorylated carbohydrate that can be found in high amounts inmost cereals, legumes, nut oil, seeds and soy beans. It has been suggested to play a significant role in inhibition ofcolorectal cancer. This study was conducted to investigate expression changes of β-catenin and cyclooxygenase-2(COX-2) and cell proliferation in the adenoma-carcinoma sequence after treatment with rice bran PA byimmunocytochemistry. Materials and
Methods: Seventy-two male Sprague-Dawley rats were divided into 6equal groups with 12 rats in each group. For cancer induction two intraperitoneal injections of azoxymethane(AOM) were given at 15 mg/kg bodyweight over a 2-weeks period. During the post initiation phase, two differentconcentrations of PA, 0.2% (w/v) and 0.5% (w/v) were administered in the diet.
Results: Results of ß-catenin,COX-2 expressions and cell proliferation of Ki-67 showed a significant contribution in colonic cancer progression.For ß-catenin and COX-2 expression, there was a significant difference between groups at p<0.05. With Ki-67,there was a statistically significant lowering the proliferating index as compared to AOM alone (p<0.05). Asignificant positive correlation (p=0.01) was noted between COX-2 expression and proliferation. Total ß-cateninalso demonstrated a significant positive linear relationship with total COX-2 (p=0.044).
Conclusions: This studyindicated potential value of PA extracted from rice bran in reducing colonic cancer risk in rats.