Effect of selenium-enriched broccoli diet on differential gene expression in min mouse liver 1,2

Abstract

Multiple intestinal neoplasia (Min) mice are a good model for investigating the effects of dietary alterations in a genetic model for intestinal cancer. Previous studies have shown that selenium-enriched broccoli effectively reduces colon cancer susceptibility. Although colon cancer cells mainly metastasize to the liver, little is known about the effects of selenium-enriched broccoli on gene expression in mouse liver. To better understand the protective role for selenium-enriched broccoli in tumorigenesis, a gene profile of the mouse liver was analyzed. Mice were fed either 0.11 mg selenium/kg control diet or 2.1 mg selenium/kg selenobroccoli diets for 10 weeks. Use of mouse pathway finder-1 GEArrays revealed that selenium-enriched broccoli moderately increased ikBακB, hsp86, gadd45 gene transcripts. In addition, analysis of the binding of liver nuclear proteins to 32P-labeled probes demonstrated that selenium-enriched broccoli enhanced the binding of transcription factor p53, NFκB, AP-1 to their cis-acting elements. Collectively, these results suggest for the first time that selenium-enriched broccoli activates certain pro-apoptotic genes linked to p53, NFκB and stress signal pathways in response to “danger signals” such as tumorigenesis.