13 Dec UW researchers find previously unknown links between microbial bile acids and the risk of colon cancer
From left, Ting Fu, assistant professor in the UW–Madison School of Pharmacy, postdoctoral researcher Xingchen Dong, and graduate student Fei Sun prepare samples for examination. Image by Sally Griffith-Oh / UW–Madison
Microbes living in our guts help us digest food by reshaping the bile acids that our livers produce for breaking down fats. It turns out that two of these microbially-modified bile acids may affect our risk — in opposite directions — for developing colon cancer.
The link between these bile acids and colon cancer risk was recently uncovered as University of Wisconsin–Madison scientists sought to better understand the relationship between gut microbes and our bodies.
In many ways, that relationship revolves around a specific protein called the farnesoid X receptor, or FXR, which helps maintain a healthy gut through its intimate relationship with bile acids. FXR controls the production of bile acids in the liver, but it also responds in different ways to the presence of various bile acids that microbes have modified.
“Some microbial bile acids support FXR’s function, while others antagonize it,” says Ting Fu, an assistant professor in the UW–Madison School of Pharmacy. Fu and her colleagues previously identified the protein as a promising drug target for treating inflammatory bowel disease and colitis, a debilitating gastrointestinal condition that raises the risk for colon cancer.
Now, a team led by Fu, pharmacy professor Jiaoyang Jiang and Dustin Deming, an associate professor in the UW School of Medicine and Public Health, have identified two microbial bile acids that have opposing effects on FXR during the development of tumors in the intestines, with one supporting its function and the other inhibiting it.