Deoxycholic acid (DCA), a secondary bile acid that is increased by high dietary fat intake – a western diet – has been linked to intestinal carcinogenesis.

In a previous study, Fang Yan, MD, PhD, and colleagues showed that DCA accelerated the progression of adenoma to adenocarcinoma in mice that spontaneously develop intestinal adenomas. Now, the researchers have studied the effect of DCA on the gut microbiota – the microbial species living in the gut.

They report in the International Journal of Cancer that DCA treatment alters the composition of the intestinal microbiota (induces dysbiosis) in the mouse model of intestinal cancer. This dysbiosis disrupted the intestinal barrier and caused inflammation and tumor progression.

Transfer of fecal microbiota from DCA–treated mice to non DCA–treated mice induced inflammation, recruited tumor–associated macrophage cells and activated the tumor–associated Wnt signaling pathway. Depletion of the gut microbiota with antibiotics reduced inflammation and tumor growth.

The findings demonstrate that DCA–induced alteration of the gut microbiota promotes intestinal carcinogenesis.