Modulation of the intestinal microbiota by 15 kDa selenoprotein expression in inflammatory colon cancer

Abstract

The intestinal microbiota is sensitive to inflammation that may induce dysbiosis leading to colon cancer. Selenium, when incorporated into the 15 kDa selenoprotein (Sep15) has a tissue-specific role in carcinogenesis. Sep15-/- mice are protected from preneoplastic colonic lesions, aberrant crypt foci (ACF). These mice were used to investigate relationships among the intestinal microbiota, Sep15, and tumorigenesis in inflammatory colon cancer using azoxymethane (AOM) and dextran sulfate salt (DSS). Sep15-/- and Sep15+/+ mice were given adequate selenium for 20 weeks alongside AOM/DSS or control treatment. Colonic ACF, tumor formation, and pro-inflammatory serum cytokines were analyzed, and murine fecal samples were utilized to categorize the intestinal microbiota. My results demonstrate that in this model, Sep15-/- mice are protected from ACF but not colonic tumorigenesis, and Sep15-/- mice may resist changes in microbiota content. Sep15 has a complex role in colon cancer initiation but may not control cancer promotion or impact microbiota composition.