Study finds link between liver cancer and gut bacteria in obese mice

June 27, 2013 by Bob Yirka report

(Medical Xpress)—A team of cancer specialists from several Japanese research facilities has found that an acid produced by a type of gut bacteria appears to be involved in causing an increase in the rates of liver cancer in obese mice. In their paper published in the journal Nature, the team reports that increased levels of deoxycholic acid (DCA) found in obese mice leads to higher rates of liver cancer.

Scientists and other health care workers have known for some time that obese people tend to have higher rates of . Until now, however, the link between obesity and such cancers has been a mystery. Suspecting gut microbiome differences between lean and obese people might offer some clues, the researchers performed several tests on mice.

The first test involved causing some mice to become obese by feeding them excess fat, while feeding another group normally. Doing so did not appear to increase the chances of any of the mice getting liver cancer. Suspecting that it was possible that along with another might cause a different outcome, the researchers fed both groups chemicals known to increase liver cancer rates. The chemicals caused all of the to get liver cancer, but only 5 percent of the lean mice. The researchers noted also that the obese mice that got cancer also had higher levels of senescent-associated secretory phenotype (SASP). Senescence is the process by which cell division slows as people grow older. In most cases, higher levels result in fewer tumors developing. In other instances, SASP has been shown to increase the likelihood of developing certain cancers such as those that develop in the liver.

Because increased SASP levels have been linked to changes in the gut microbiome, the researchers fed another group of mice a mixture of that killed most of the in their guts, then repeated their first exercise. They found that in the absence of , liver cancer rates for the obese mice plummeted. The next challenge was to figure out why gut bacteria was causing the change.

After an exhaustive process of elimination, the researchers found obese mice had elevated levels of deoxycholic acid (DCA)—a by-product of the metabolism of bile by some gut bacteria—in their bloodstreams. Further tests found that artificially raising or lowering DCA levels caused associated raising or lowering of liver cancer rates.

The net result of the all the testing by the team showed that obese mice tended to have more of the DCA producing microbes in their guts than lean mice, which in turn led to more liver cancers—a finding that will need to be tested to see if it applies to humans as well. If so, drugs that lower such rates may be developed to help prevent liver cancer in people.

Explore further: In obesity, a micro-RNA causes metabolic problems

More information: Nature (2013) doi:10.1038/nature12347

Related Stories

In obesity, a micro-RNA causes metabolic problems

September 20, 2012

Scientists have identified a key molecular player in a chain of events in the body that can lead to fatty liver disease, Type II diabetes and other metabolic abnormalities associated with obesity. By blocking this molecule, ...

Cardio could hold key to cancer cure

April 26, 2013

Regular exercise has been proven to reduce the chance of developing liver cancer in a world-first mice study that carries hope for patients at risk from hepatocellular carcinoma (HCC).

Gut microbe battles obesity

May 14, 2013

(Medical Xpress)—Akkermansia muciniphila is one of the many microbes that live in our intestines. This bacterium, which feeds on the intestine's mucus lining, comprises between 3 and 5 percent of the gut microbes of healthy ...

Cocoa may help fight obesity-related inflammation

June 12, 2013

(Medical Xpress)—A few cups of hot cocoa may not only fight off the chill of a winter's day, but they could also help obese people better control inflammation-related diseases, such as diabetes, according to Penn State ...

Recommended for you

An accessible approach to making a mini-brain

October 1, 2015

If you need a working miniature brain—say for drug testing, to test neural tissue transplants, or to experiment with how stem cells work—a new paper describes how to build one with what the Brown University authors say ...

Tension helps heart cells develop normally in the lab

October 1, 2015

The heart is never quite at rest, and it turns out that even in a lab heart cells need a little of that tension. Without something to pull against, heart cells grown from stem cells in a lab dish fail to develop normally.

Dormant viral genes may awaken to cause ALS

September 30, 2015

Scientists at the National Institutes of Health discovered that reactivation of ancient viral genes embedded in the human genome may cause the destruction of neurons in some forms of amyotrophic lateral sclerosis (ALS). The ...


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.