Researchers from Case Western Reserve University School of Dental Medicine have discovered how a common oral bacterium can contribute to colorectal cancer (Cell Host & Microbe, August 14, 2013, Vol. 14:2, pp. 195-206).
"We found this cancer is linked to an infection from [the bacterium]," said lead study investigator Yiping Han, PhD, a professor of periodontics at the dental school. "This discovery creates the potential for new diagnostic tools and therapies to treat and prevent the cancer."
The results of the research were published in conjunction with a second study from a different research group that highlights how the bacteria can speed the accumulation of cancerous cells.
The researchers also learned how to prevent the microorganism, called Fusobacterium nucleatum (Fn), from attaching to colon cells and potentially triggering a cascade of changes that can lead to cancer.
The latest findings advance research from 2011, in which Han and her team identified an adhesive molecule on Fn's surface, called FadA, which can attach to VE-cadherin, a cell receptor from the cadherin group on blood vessels.
As Han completed the work on FadA and VE-cadherin, researchers from Harvard University and the University of British Columbia discovered the presence of Fn was higher in malignant tumors compared with the surrounding tissue.
Han said she immediately suspected Fn interacted with cells in the colon similarly to those in blood vessels and shifted her lab's work to focus on colorectal cancer.
Subsequently, FadA's attachment to E-cadherin set in motion a protein called β-catenin, which, among its many functions, produces two important actions in the cancer process: an inflammatory response that alters the immune system, and another that spurs cancer cell growth.
Han's lab designed a novel synthetic peptide that prevents FadA from attaching to E-cadherin and inciting actions that lead to cancer development.
They also found that the FadA gene levels are 10 to 100 times higher than normal in precancerous and malignant colon polyps.
A patent application has been filed on work associated with this research.