Although health experts have long been aware that obese individuals have a 50 percent higher chance of developing colorectal cancer compared to lean people, the link between the metabolic condition and the increased cancer risk has not been clearly understood. Now, a new study has shown the biological connection between the two.
In the process, the researchers identified an FDA-approved drug that can potentially prevent the development of the cancer.
For the new study published in Cancer Research, author Scott Waldman from Thomas Jefferson University, along with his colleagues, placed genetically engineered mice on different diets. They found that giving mice a high-caloric diet resulted in the loss of guanylin, a key hormone in the intestine.
The guanylin hormone receptor serves as a tumor suppressor and, in the absence of the hormone, this receptor is silenced, setting off conditions that could lead to cancer development.
Through genetic replacement of this hormone, however, the tumor suppressor can be reversed. In the study, this prevented the development of cancer even if the animals continued to consume excess calories.
The results suggest that the pill linaclotide (Linzess) can be potentially used to prevent colorectal cancer in obese patients as it is structurally related to the lost hormone.
The drug is already approved by the FDA in 2012. It was green-lighted as treatment for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC).
Waldman said that their findings suggest the possibility of preventing colorectal cancer in obese individuals.
This can also be done through hormone replacement therapy in other diseases linked with hormone deficiency, such as in the case of insulin loss among diabetics.
"While we know the hormone is lost in the obese mice, its receptors are just sitting there waiting to be switched on," Walden said. "If you can prevent hormone loss, you can also prevent tumor development. These findings suggest that a drug like linaclotide, which acts like guanylin, can activate GUCY2C tumor-suppressing receptors to prevent cancer in obese patients."
Colorectal cancer is the second leading cancer killer in the U.S. Besides obesity, age is also a risk factor for the disease, with more than 90 percent of the cases occurring in people aged 50 or older.
Family history of colorectal cancer and unhealthy lifestyle practices, such as lack of physical activity, tobacco use and alcohol consumption, also up the risk for the disease.
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