GAINESVILLE, FLA. -- A mutant form of an unassuming microbe deals a blow to colon cancer, University of Florida scientists have discovered.
The special bacteria halted abnormal inflammation, reduced precancerous growths and reversed progression of severe cancerous lesions in the large intestines of mice.
The findings appeared this month in the Proceedings of the National Academy of Sciences.
For years researchers have understood that uncontrolled inflammation in the large intestine can result in various diseases, including colon cancer and inflammatory bowel diseases.
The new study focused on understanding how to curb immune system processes in the gut that lead to harmful inflammation.
Some inflammation in the gut is a good thing, as it serves to keep the body's immune system in top disease-fighting shape.
Under stress, however, the immune system overreacts with a cascade of inflammation-causing reactions.
That can lead to afflictions in which the immune system attacks instead of protects the body. It can even cause colon cancer.
U-F researchers had previously demonstrated that a genetically modified form of the beneficial bacterium 'Lactobacillus acidophilus' can bring overactive immune responses back to normal.
They have now found that proteins on the surface of the bacteria can act on the immune system to either cause inflammation in the gut or tune it down.
The researchers removed an inflammation-causing gene from the bacterium, and the result was a form of the bacteria that was even better at controlling disease-causing inflammation.
Researchers further discovered that mice with severe cases of polyps and cancerous intestinal lesions that were fed the modified bacteria had significantly reduced numbers of colon polyps compared with untreated mice, and showed no signs of active colon cancer or disease-causing inflammation.
The modified bacteria are easy and cost-effective to produce.
Researchers say that, eventually, a treatment for humans could be a pill that can be taken by mouth.
Patients could receive the beneficial bacterial treatment in combination with surgery or other therapies.