Study suggests colon cancer cells carry bacteria with them when they metastasize

November 24, 2017 by Bob Yirka, Medical Xpress report
Credit: Baylor College of Medicine

(Medical Xpress)—A team of researchers working at Harvard University has found evidence that suggests a certain type of bacteria found in colon cancer tumors makes its way to tumors in other body parts by traveling with the metastasizing cells. In their paper published in the journal Science, the group describes their study of the bacteria and its possible link to being a cause of colon cancer.

Prior research has shown that bacteria exist alongside for various types of cancers, causing some in the medical field to wonder if they are actually the cause of . One such type of bacteria, Fusobacterium nucleatum, has been found to exist alongside colon cancer tumor cells. In this new effort, the researchers wondered if the same bacteria might exist alongside colon cancer tumor cells that have migrated to another part of the body, specifically, the liver.

To find out, the researchers collected tissue samples from actual patients. In so doing, they found that in many cases the same strain of bacteria was present in tumors in both the colon and liver in patients where the cancer had metastasized. They also found that patients who had colon cancer but had no evidence of the bacteria in their tumors, also did not have the bacteria in their .

Intrigued by the findings, the researchers implanted tumors from human patients into healthy rats. In so doing they found that those tumors which also had the bacteria took hold and began growing. Those tumors that did not have the bacteria, on the other hand, failed to take hold. The team next tested the possibility of treating the in mice by treating them with an antibiotic known to kill F. nucleatum. They found that doing so did indeed slow the growth of the tumor.

In looking at all of their findings, the suggest that it appears that the bacteria do travel with the tumor cells to a new site and remain with new tumors that develop in those sites. They suggest further that it might be possible that the bacteria aides in colonization at the new site. More research will be done, of course, to determine if the actually play a role in the development of tumors.

Explore further: Bacteria protect intestinal tumor model from being killed by immune cells

More information: Susan Bullman et al. Analysis ofFusobacteriumpersistence and antibiotic response in colorectal cancer, Science (2017). DOI: 10.1126/science.aal5240

Abstract
Colorectal cancers comprise a complex mixture of malignant cells, non-transformed cells and microorganisms. Fusobacterium nucleatum is among the most prevalent bacterial species in colorectal cancer tissues. Here we show that colonization of human colorectal cancers with Fusobacterium and its associated microbiome, including Bacteroides, Selenomonas and Prevotella species, is maintained in distal metastases, demonstrating microbiome stability between paired primary-metastatic tumors. In situ hybridization analysis revealed that Fusobacterium is predominantly associated with cancer cells in the metastatic lesions. Mouse xenografts of human primary colorectal adenocarcinomas were found to retain viable Fusobacterium and its associated microbiome through successive passages. Treatment of mice bearing a colon cancer xenograft with the antibiotic metronidazole reduced Fusobacterium load, cancer cell proliferation and overall tumor growth. These observations argue for further investigation of antimicrobial interventions as a potential treatment for patients with Fusobacterium-associated colorectal cancer.

Related Stories

Bacteria protect intestinal tumor model from being killed by immune cells

February 11, 2015
Bacteria that are commonly found in the mouth are often abundant in patients with colon cancer, but the potential role these microbes play in tumor development has not been clear. A study published by Cell Press February ...

Genetically altered bacteria help destroy cancerous tumors in mice

February 9, 2017
(Medical Xpress)—A team of researchers affiliated with multiple institutions in Korea has found that genetically altering a type of bacteria and injecting it into cancerous mice resulted in the disappearance of tumors in ...

Scientists find bacteria in pancreatic tumors that metabolize a common drug

September 15, 2017
To the reasons that chemotherapy sometimes does not work, we can now add one more: bacteria. In a study published today in Science, researchers describe findings that certain bacteria can be found inside human pancreatic ...

Rat study shows gut microbes play a role in colon cancer susceptibility

July 13, 2016
The microscopic organisms that live in our gut do more than help us digest food. A new study in rats bolsters a growing body of evidence that the complex mix of microorganisms found in the gut, known as gut microbiota, could ...

AZD6738 found to slow some types of children's tumor growth in mouse models

November 2, 2017
(Medical Xpress)—A team of researchers from the U.S., Germany and Japan has found that the chemical AZD6738 was able to slow some childhood type tumor growths in mouse models. In their paper published in the journal Science ...

How mouth microbes may worsen colorectal cancer

August 10, 2016
Bacteria commonly found in the mouth have been recently shown to worsen colorectal cancer in animals, but it has not been clear how these microbes make their way to the gut in the first place. A study published August 10 ...

Recommended for you

Single-cell study in a childhood brain tumor affirms the importance of context

April 20, 2018
In defining the cellular context of diffuse midline gliomas, researchers find the cells fueling their growth and suggest a potential approach to treating them: forcing their cells to be more mature.

Aggressive breast cancer already has resistant tumour cells prior to chemotherapy

April 20, 2018
Difficult to treat and aggressive "triple-negative" breast cancer is chemoresistant even before chemotherapy begins, a new study by researchers from Karolinska Institutet and the University of Texas MD Anderson Cancer Center ...

Mechanism that drives development of liver cancer brought on by non-alcoholic fatty liver disease discovered

April 19, 2018
A team of researchers from several institutions in China has found a mechanism that appears to drive the development of a type of liver cancer not caused by alcohol consumption. In their paper published in the journal Science ...

Discovery adds to evidence that some children are predisposed to develop leukemia

April 19, 2018
St. Jude Children's Research Hospital researchers have made a discovery that expands the list of genes to include when screening individuals for possible increased susceptibility to childhood leukemia. The finding is reported ...

Scientists identify 170 potential lung cancer drug targets using unique cellular library

April 19, 2018
After testing more than 200,000 chemical compounds, UT Southwestern's Simmons Cancer Center researchers have identified 170 chemicals that are potential candidates for development into drug therapies for lung cancer.

Chip-based blood test for multiple myeloma could make bone biopsies a relic of the past

April 19, 2018
The diagnosis and treatment of multiple myeloma, a cancer affecting plasma cells, traditionally forces patients to suffer through a painful bone biopsy. During that procedure, doctors insert a bone-biopsy needle through an ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

LaPortaMA
not rated yet Nov 25, 2017
Strep D/Strep faecalis known for decades.
Chris_Reeve
Nov 26, 2017
This comment has been removed by a moderator.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.