Illustration showing colorectal cancer
Credit: Mohammed Haneefa Nizamudeen/Getty Images

Researchers at the University of Pittsburgh School of Medicine report in the journal Immunity, that a bacterium common in the mouse gut microbiome may aid the immune system in fighting cancer cells in the colon. These new findings could eventually inform the development of new therapeutics based on the small molecules produced by such beneficial bacteria.

“The composition of the intestinal microbiota is associated with both the development of tumors and the efficacy of anti-tumor immunity,” the researchers wrote. “Here, we examined the impact of microbiota-specific T cells in anti-colorectal cancer (CRC) immunity.”

“Altering the gut microbiome doesn’t have to rely on serendipity to get a therapeutic advantage,” explained Timothy Hand, PhD, assistant professor of immunology at Pitt and corresponding author. “Instead of using fecal transplants and hoping to get the right microbial composition, we now are much better positioned to develop effective drugs designed based on molecules produced by beneficial bacteria.”

The Pitt researchers colonized the guts of mice with colon cancer with Helicobacter hepaticus.

“Introduction of H. hepaticus (Hhep) in a mouse model of CRC did not alter the microbial landscape but increased tumor infiltration by cytotoxic lymphocytes and inhibited tumor growth,” the authors wrote.

The researchers observed increased infiltration of helper T cells, B cells, and natural killer cells to the tumor site.

“Ignoring the influence of gut bacteria on the success of cancer therapies seems like a massive oversight,” said lead author Abigail Overacre-Delgoffe, PhD, a postdoctoral fellow in Pitt’s department of pediatrics and a Damon Runyon Fellow. “We need to think about all the things that patients go through day to day that can cause treatments to succeed or fail. We can’t ignore the bacteria anymore—they influence everything.”

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