www.chiropractic-lane.com 07105
Mouth Bacteria May Be Linked to Colorectal Cancer
A kind of bacteria, Fusobacterium nucleatum, commonly found in the mouth (which is often the culprit in gum disease) also spurs the formation of tumors in colon cancer, researchers report today. Over the last two years, a series of genetic studies on human colon biopsies revealed that one family of microbes — Fusobacteria — is present in healthy tissue adjacent to colorectal cancer.
Scientists had previously found that the level of Fusobacterium nucleatum in the gut was higher among people with colon cancer. That was noteworthy because fusobacteria aren’t one of the usual strains found in the healthy gut.
However up to now it hasn’t been clear whether the foreign bacteria caused tissue to turn cancerous or whether the bacteria was a result of the cancer. Now, researchers report that the bacteria in fact stimulates tumors, and they identify the molecule responsible for the bug’s harmful effects.
A Common Cancer
Colon cancer is the second-leading cause of cancer death in the United States, and more than 1 million new cases are diagnosed worldwide each year. By figuring out how fusobacteria spur cancerous tumors, scientists can work toward therapies that may inhibit the bacterium’s activity and possibly eradicate it altogether from colon tissue.
Previous studies have focused on a subset of colon cancer that is caused by inflammatory bowel disease, or conditions linked to inflammation of the colon and small intestines.
Colon Cancer and Bacteria
A team from Harvard and the Dana-Farber Cancer Institute report that fusobacteria are prevalent in colon adenomas, essentially early-stage benign tumors that over time can turn malignant. Working with mice that were known to develop intestinal tumors, the team was able to accelerate early tumor formation by feeding them fusobacteria.
Researchers also fed them three other bacteria strains, such as Streptococcus, that are known to be associated with colon cancer. Tumors formed at a higher rate in mice fed with fusobacteria versus those who got Streptococcus.
Fusobacteria were stealthy and worked at the micro-inflammation level—the Harvard team saw no large-scale intestinal inflammation.
Molecular Culprit
A second research team from Case Western Reserve University found the specific molecule that allows such stealthy invasion: a molecule called FadA. Gene expression levels of FadA were 10 to 100 times higher in colon tissues from patients with adenomas and cancerous tumors when compared with healthy participants.
Researchers also determined how FadA worked its dangerous magic: by blocking the expression of a gene that inhibits tumor growth. Both studies are published today in Cell Host & Microbe.
“We showed that FadA is a marker that can be used for the early diagnosis of colon cancer and identified potential therapeutic targets to treat or prevent this common and debilitating disease,” says Yiping Han of Case Western Reserve University School of Dental Medicine.
Gum Disease-Linked Mouth Bacteria May Cause Colorectal Cancer
New research connects gum disease-causing mouth bacteria to tumor growth in the colon and reveals a possible drug candidate that may prevent some types of colorectal cancer.
Colorectal cancer is the second most common form of cancer in the world, with rates being about 30 percent higher in developed countries. Nearly 50,000 people in the U.S. will die from colorectal cancer this year.
Although Fusobacteria start off in the mouth and are frequently associated with gum disease, they can migrate through blood vessels to the far reaches of the intestinal tract, including the colon. However, none of these earlier investigations had observed the bacteria within the actual tumors.
“Fusobacteria may provide not only a new way to group or describe colon cancers but also, more importantly, a new perspective on how to target pathways to halt tumor growth and spread,” said senior study author Dr. Wendy Garrett of the Harvard School of Public Health and the Dana-Farber Cancer Institute.
Fusobacteria’s Growing ‘Fad’
The second investigation examined how Fusobacteria are able to set up shop in the intestines. In 2011, a research team led by Dr. Yiping Han, a professor of periodontics at Case Western, found that Fusobacteria produce an adhesion molecule called “FadA” that allows the microbe to attach to blood vessels.
In their latest study, they found that FadA levels were between 10 and 100 times higher in patients with adenomas and adenocarcinomas, the cancerous cousin of the former.
In addition, her team designed a novel synthetic peptide that could block FadA and prevent Fusobacteria from invading cells growing in a Petri dish. They are now filing for a patent and believe this work will lead to possible treatments for colon cancer as well as oral disease.
“FadA can be used as a diagnostic marker for early detection of colon cancer,” concluded Han. “It can also be used to determine if treatment works effectively at reducing Fn load in the colon and the mouth.”
Sources:
Sources: Roxana Rubinstein MR, Wang X, Liu W, Hao Y, Cai G, Han YW.Fusobacterium nucleatum Promotes Colorectal Carcinogenesis by Modulating E-Cadherin/b-Catenin Signaling via its FadA Adhesin. Cell Host & Microbe. 2013.
Kostic AD, Chun E, Robertson L, et al. Fusobacterium nucleatum Potentiates Intestinal Tumorigenesis and Modulates the Tumor-Immune Microenvironment. Cell Host & Microbe. 2013.
via Blogger http://chiropractic-lane.blogspot.com/2013/08/mouth-bacteria-may-be-linked-to-colorn.html
Recent Comments