Effect of lunasin-rich soybean extract upon TNF-α expression on colonic epithelial cells of mice induced by azoxymethane/dextran sodium sulfate

Objective: Colorectal cancer (CRC) contributes to 9.7% of all cancer, and its pathogenesis is related to chronic inflammation. However, current cancer therapy options are lacking, and peptide in food has become popular among researchers because it is cheap, easy to get, has a low toxicity, and is a promising cancer-preventing agent. This research aimed to investigate whether lunasin from soybeans can reduce the expression of pro-inflammatory cytokine TNF-α in colonic epithelial cells. Methods: Thirty Swiss Webster mice were randomly allocated to six groups. One group was normal, and in five groups, carcinogenesis was induced using azoxymethane (AOM) and dextran sodium sulfate (DSS). The mice were then given nothing (negative control), aspirin (positive control), and lunasin-rich soybean extract (LSE) in three different doses (250, 300, and 350 mg/kgBW) for four weeks. Distal colon tissue was immunohistochemically stained and then observed under a light microscope with 400X magnification to count epithelial cells, based on their color. The index was calculated using optical density scores. Results: LSE was shown to decrease the expression of tumor necrosis factor (TNF)-α. This decrease was statistically significant between the negative control and a dose of 300 mg/kgBW (p=0.016) and 350 mg/kgBW (p=0.009), yet it was not significant with a dose of 250 mg/kgBW (p=0.754). Conclusion: A dose of 300 mg/kgBW or higher of LSE can reduce the expression of TNF-α.