Bacillus coagulans (species of lactic acid-forming Bacillus bacteria) ameliorates azoxymethane and dextran sodium sulfate-induced colon cancer in mice

Lactic acid bacteria exhibit antitumor effects in mouse models of cancer. However, the effects of lactic acid bacteria on cancer remain unknown. This study investigated its effect in a mouse model of chronic inflammation-associated colon cancer induced by azoxymethane (AOM) and dextran sodium sulfate (DSS). Administration of Bacillus coagulans ameliorated AOM+DSS-induced colon cancer in mice. B. coagulans increased the expression of transforming growth factor (TGF)-β, mothers against decapentaplegic homolog (Smad) 2/3, and p21, a cyclin-dependent kinase inhibitor (CDKI); and decreased that of the c-myelocytomatosis oncogene product (c-Myc). Furthermore, reductions in phosphatidylinositol-3 kinase (PI3K), phospho-protein kinase B (pAKT), and mechanistic target of rapamycin (mTOR) levels were observed after B. coagulans administration. Additionally, increased I kappa B (IκB) and decreased interleukin (IL)-6 and interferon (IFN)-γ levels were detected. The ameliorating effect of B. coagulans on colon cancer may be induced by the combined actions of TGF-β/Smad2/3/p21・C-Myc, PI3K/AKT/mTOR, and IκB/IL-6・IFN-γ.