An international team of researchers used wrinkle-removing Botox to slow the growth of stomach cancer in mice by blocking nerve signals to cancer stem cells. While this study was done in mice, it paves the way for potential new treatments in people.
Researchers from Columbia University, the Norwegian University of Science and Technology, and other institutions investigated the role that nerves play in the growth of stomach cancer in the study, published Aug. 20 in Science Translational Medicine.
"Scientists have long observed that human and mouse cancers contain a lot of nerves in and around the tumor cells," said Dr. Timothy Wang, a professor of medicine at Columbia University’s Herbert Irving Comprehensive Cancer Center, in a press statement. "We wanted to understand more about the role of nerves in the initiation and growth of cancer, by focusing on stomach cancer."
Injection Boosts Chemotherapy in Mice
The tumors grew more slowly when researchers disrupted the signals from the vagus nerve to the stomach cancer. One method they used to accomplish this was to surgically cut the nerve, a procedure called a vagotomy.
The researchers were also able to sever that link by injecting Botox — the commercial name for botulinum toxin, commonly used as a cosmetic drug — into the area around the nerve. This blocked the release of the neurotransmitter acetylcholine from the vagus nerve. The procedure was essentially a chemical vagotomy.
"We found that blocking the nerve signals makes the cancer cells more vulnerable — it removes one of the key factors that regulate their growth," Wang said.
Cutting the cancer off from the nerve also enhanced the effectiveness of chemotherapy. Mice who had either botulinum toxin injections or vagotomy alongside the traditional cancer treatment had better survival rates.
“For most patients, we are suggesting that denervation works best in combination with traditional chemotherapy,” Wang said, “since loss of nervous input appears to make cancer cells more vulnerable to chemotherapy, which makes the chemotherapy more efficient as well.”
According to the National Cancer Institute, stomach cancer will affect more than 22,000 people in 2014, with almost 11,000 people dying from the disease.
Botox Could Provide Additional Option
The study has led to a clinical trial for patients with stomach cancer in Norway, which will start soon. Even though scientists have not yet tested the technique in people, using botulinum toxin could provide a safe and effective method of treating stomach cancer.
“Botox injection to create a chemical vagotomy for patients with gastric [stomach] cancer offers a minimally invasive option for patients who may not be candidates for surgical vagotomy,” said Dr. James J. Lee, a gastroenterology specialist with St. Joseph Hospital in Orange, California, in an email to Healthline. “Also, the Botox injection is not permanent and the result is usually reversible in six months to one year, so that there would be less concern for the long-term and permanent effect of vagotomy.”
Technique Focused on Early Stage Tumors
One drawback of the study is that the researchers focused mainly on the early stages of stomach cancer.
“Since gastric cancers are mostly diagnosed in the later stage,” Lee said, “how would the Botox or vagotomy affect tumor behavior outside of the stomach or in the lymph nodes?”
Treatment is easier and survival rates are better when the cancer is localized and has not yet spread. Unfortunately, at the time of diagnosis, only 10 to 20 percent of all cases are at an early stage.
Once the stomach cancer has spread to other parts of the body, the five-year survival rate for stomach cancer drops to less than 5 percent, from a 50 percent survival rate in earlier stages.
The researchers plan on addressing this in additional studies, along with developing other drugs that block the neurotransmitter receptors.
"In the future,” Wang said, “we’d really like to look at how we can use this method of targeting nerves to stop the growth of more advanced tumors.”