Chrysin-Enhanced Cytotoxicity of 5-Fluorouracil-Based Chemotherapy for Colorectal Cancer in Mice: Investigating its Effects on Cyclooxygenase-2 Expression

Abstract 5-fluorouracil (5-FU) has been recognized as an effective medication used to treat colorectal cancer (CRC); however, its administration is facing limitations due to some complications reported. It is also generally accepted that combination therapy is among strategies to improve chemotherapy efficiency. Therefore, chrysin, with its anticancer effects, in combination with 5-FU was investigated in the present study. Azoxymethane (AOM) as a carcinogenic substance along with dextran sodium sulfate (DSS) was additionally utilized to induce CRC in mice. The anticancer effects of chrysin were then evaluated using aberrant crypt foci (ACF) counting and percentage of pathologic lesions in epithelial tissues from distal colon. In this study, cyclooxygenase (COX-2) protein expression was correspondingly explored through immunohistochemistry (IHC). The results revealed that chrysin alone or in combination with 5-FU could decrease ACF counting and percentage of pathologic lesions in comparison with AOM (p<0.05). Moreover, the combination of chrysin (at a dose of 50 mg/kg) with 5-FU reduced COX-2 expression compared with 5-FU alone (p<0.001) or 5-FU in combination with chrysin at a dose of 100 mg/kg (p<0.05). Furthermore, the combined chrysin boosted 5-FU efficiency, so it was suggested as an auxiliary therapy for CRC.