Is E. Coli the Next Cancer Therapy?

Image courtesy of Vik Muniz and Tal Danino.

E. coli is most commonly associated with extremely unpleasant illnesses. But researchers at MIT and the University of California at San Diego may have found a new use for the bacteria.

The researchers are reprogramming harmless strains of E. coli to destroy tumor cells. This “super microbe,” which can be ingested or injected, could offer a new way to stave off liver cancer.

Since bacteria is naturally attracted to disease sites, tumors offer very friendly environments for bacteria to grow, explains lead scientist Sangeeta Bhatia in a recent release, making bacteria like E. coli uniquely helpful in breaking them down. The re-engineered bacteria can be programmed to attack tumors in three different ways.

First, it can produce a molecule called hemolysin, which damages the tumor cells’ essential membranes. Another method induces the tumor cells to undergo “programmed suicide.” Finally, the E. coli can release a protein that stimulates the body’s immune system.

To guard against unplanned side effects, the E. coli bacteria is also engineered to self-destruct when too many other bacterial cells are present. This lets the “army” take a short break before beginning the cycle again, and keeps the patient’s total bacterial levels low.

The tactic may seem crazy, but it’s so crazy it just might work. Researchers have tested the E. coli method in mice, using it to battle a very aggressive form of colon cancer that had spread to the liver. The bacteria was shown to reduce tumor size slightly on its own, but, perhaps more importantly, it induced a dramatic reduction when combined with chemotherapy drug 5-fluorouracil.

Bhatia notes in the release that this particular combination therapy—using orally ingested bacterial drugs with 5-fluorouracil or other traditional treatments—could one day be highly effective against liver cancer in humans.