Monthly Archives: September 2019

How A Common Oral Bacteria Makes Colon Cancer More Deadly

Researchers at the Columbia University College of Dental Medicine have determined how F. nucleatum — a common oral bacteria often implicated in tooth decay — accelerates the growth of colon cancer. The study was published online in the journal EMBO Reports. The findings could make it easier to identify and treat more aggressive colon cancers. It also helps explain why some cases advance far more quickly than others, thanks to the same bacteria found in dental plaque.

Colon cancer is the second leading cause of cancer death in the U.S. Researchers have long known that the disease is caused by genetic mutations that typically accumulate over the course of a decade.

Images of noncancerous (far left) versus cancerous colorectal tissue (middle and right) from the same patient who was infected with F. nucleatum. Red indicates the FadA adhesin, a protein that is produced by the bacterium and accelerates cancerous tumor growth. Green indicates Annexin A1, a protein released in increasing amounts by cancerous tissue when infected with F. nucleatum.

Mutations are just part of the story,” says study leader Yiping W. Han, PhD, professor of microbial sciences at Columbia University’s College of Dental Medicine and Vagelos College of Physicians & Surgeons. “Other factors, including microbes, can also play a role.”

Scientists have also demonstrated that about a third of colorectal cancers are associated with a common oral bacterium called F. nucleatum. Those cases are often the most aggressive, but nobody knew why. In a prior study, Han’s research team discovered that the bacterium makes a molecule called FadA adhesin, triggering a signaling pathway in colon cells that has been implicated in several cancers. They also found that FadA adhesin only stimulates the growth of cancerous cells, not healthy cells.  “We needed to find out why F. nucleatum only seemed to interact with the cancerous cells,” says Han.


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