By Chuck Seegert, Ph.D.
Illness has often been tied to bacterial disturbances in the human body. Recently, a new bacterial imaging technique has been applied by Johns Hopkins researchers in the study of colon cancer. The researchers discovered a correlation between colon cancer and the presence of dense clumps of bacteria in the ascending colon.
Normal tissue of the colon has a mucus layer that protects the underlying cells from exposure to certain pathogens. For example, the interior skin of the colon, or epithelium, isn’t usually exposed to pathogens, like bacteria, due to this protective layer. Breaches in the mucus layer can potentially allow these cells to be exposed to disease, causing stresses that can ultimately develop into cancer.
A newly developed combinatorial imaging technique from the Marine Biological Laboratory (MBL) at Woods Hole Massachusetts has cast light on how bacteria may be causing colon cancer, according to a recent press release. Combinatorial imaging was able to show that “biofilms,” or rugged clumps of bacteria that are encased in a protective, self-produced matrix, are often present in certain types of colon cancer.
“This is the first time that biofilms have been shown to be associated with colon cancer, to our knowledge,” said co-author Jessica Mark Welch, a scientist at the MBL, in the press release.
The technique uses many different colors of fluorescent probes to light up different species of bacteria, according to the press release. Once fluoresced, the bacterial community can be visualized in 3D and studied in relationship to the colon tissue in which it resides. A key finding the team discovered is that bacteria are strongly associated with tumors on the right side of the colon, but not on the left side. Additionally, the bacteria that invade the mucosa are not of a single strain, but are represented by the majority of strains found in the biofilm away from the invasion site. This precludes the notion that a single malignant strain is responsible for the disease.
Bacteria in the biofilm seemed to contact epithelial cells after passing through the mucosa, according to a recent study published by the team in the Proceedings of the National Academy of Sciences. Bacteria invaded the tissue and appeared to change tissue biology by enhancing cellular proliferation, a feature commonly seen in the transformation of normal tissue into cancerous tissue.
“This suggests that either the tumor allows the biofilm to form, or the biofilm is helping to cause the tumor,” said Mark Welch, in the press release. “The breaching of the mucus layer could allow bacteria to come into contact with the host epithelial cells, and that is one thing that could lead to cancer.”
Given the strong relationship between biofilm presence and colon cancer, the research team believes the imaging method may hold promise as a new diagnostic method for the disease, according to the study.
Developing new diagnostics for colon cancer is a high priority in the medical device field. To help enhance the provision of medical care in areas that don’t have an established medical infrastructure, researchers have developed biomarker test strips for colon cancer.
Image Credit: Jessica Mark Welch, Blair Rossetti, and Christine Dejea