Botox is best known for its cosmetic applications, but it may be useful in treating stomach cancers, new research in mice suggests.
Researchers found that Botox injections could block certain nerve signals to the stomach, reducing the risk of developing tumors and suppressing tumor growth in mice that already had cancer.
The drug in Botox is a toxin that paralyzes the muscles by affecting the nervous system. In the study, the drug was injected into the stomach wall of the mice to silence the endings of the vagus nerve, the main nerve that connects the stomach to the brain.
"The finding that Botox was highly effective was particularly exciting," study researcher Dr. Duan Chen, a cancer researcher at the Norwegian University of Science and Technology, said in a statement. [11 Surprising Facts About the Digestive System]
The researchers are now planning to test the treatments in patients with stomach cancer in Norway.
Intercepting the signal
Stomach cancer, also called gastric cancer, occurs when tumors develop in the lining of the stomach. It is estimated that there will be 22,220 new cases of stomach cancers in the United States in 2014, and about 10,990 people will die from this cancer, according to the National Cancer Institute. In 2011, there were an estimated 74,035 people living with stomach cancer in the United States.
Researchers think the vagus nerve's signals may contribute to the development of tumors by influencing the stem cells in the gut, and turning them into cancer cells, according to the study published today (Aug. 20) in the journal Science Translational Medicine.
In the study, the researchers showed that the nerve promotes tumor growth by releasing signaling chemicals. To close this line of communication between the vagus nerve and the tumor, the researchers tried Botox, as well as several other methods. In one method they surgically cut the nerve, a procedure called vagotomy, which is sometimes used to treat people with stomach ulcers, and is being investigated as a treatment for obesity.
The researchers also gave mice a drug to block the receptor of the signaling chemicals, and in another method they modified the genes for that receptor. All methods suppressed the tumor growth, but cutting the nerve or using Botox appeared particularly effective, the researchers said.
Botox is most commonly used as a beauty treatment to temporarily paralyze facial muscles and reduce wrinkles. But it is also has other medical uses, for example, treating excessive sweating or impaired muscles.
As a cancer treatment, Botox would be less expensive and less toxic than most standard cancer treatments and has hardly any side effects, the researchers said.
"We believe this treatment is a good treatment because it can be used locally and it targets the cancer stem cells," Chen said. "It only requires the patient to stay in the hospital for a few hours."
The Botox treatment could be used along with conventional cancer therapies, such as chemotherapy, the researchers said. They found that the loss of nerve signals appeared to make the cancer cells more vulnerable to chemotherapy, and enhanced the effects of chemotherapy and prolonged the life of mice in the study.
The nerve-tumor growth connection could occur in other cancers as well, although more research is needed to investigate this, the researchers said. For example, a recent study suggested that nerves contribute to tumor development in prostate cancer. But the precise nerves that are involved may vary depending on the type and site of the cancer, the researchers said.