Intestine Bugs Could Be Key To Obesity-Cancer Link

New research shows that obesity is linked to an increase in the production of DNA-damaging acid that causes liver inflammation and cancer.

AsianScientist (Jul. 1, 2013) – Researchers in Japan report that obese mice carry an altered gut flora, which is linked to an increase in the production of DNA-damaging acid that causes liver inflammation and cancer.

Obesity, which has become more prevalent in most developed countries over the past few decades, is increasingly shown to be a major risk factor for a number of chronic diseases such as diabetes, cardiovascular diseases, and cancer. It is predicted that by 2030, about 58 percent of the world’s adult population might be either overweight or obese, revealing the severity of the epidemic.

While the link between obesity and chronic disease has been suspected, the exact molecular mechanisms that integrate these events have remained largely unclear.

In a new study reported in Nature this week, Eiji Hara and colleagues at the Cancer Institute at the Japanese Foundation for Cancer Research in Tokyo reveal how obesity enhances the development of tumors in a mouse model of liver cancer.

They showed that a high-fat diet alters the composition of intestinal bacteria, leading to an increased production of deoxycholic acid (DCA), a gut bacterial metabolite known to cause DNA damage.

The circulation of DCA induces the secretion of pro-inflammatory cytokines and tumor-promoting factors in the liver, causing DNA damage and inflammation of the liver, which is linked to liver cancer formation.

In addition, the researchers showed that blocking DCA production or reducing gut bacteria by treatment with vancomycin, an antibiotic that targets Gram-positive bacteria, efficiently reduced the development of liver cancer in obese mice.

Hence, the study revealed a link between diet, the microbiota, and cancer in mice, and may open up new possibilities for the control of liver cancer in obese individuals.

The article can be found at: Yoshimoto S et al. (2013) Obesity-induced gut microbial metabolite promotes liver cancer through senescence secretome.

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Copyright: Asian Scientist Magazine; Photo: Eiji Hara/Japanese Foundation for Cancer Research.
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