A spray-on immune booster may one day improve survival after mesothelioma surgery.
UCLA scientists tested the biodegradable spray gel in mice with advanced melanoma. They found that it stopped cancer recurrence after surgery in about half of the lab animals tested.
“Around 90 percent of people with cancerous tumors end up dying because of tumor recurrence or metastasis,” says lead investigator Zhen Gu. “Being able to develop something that helps lower this risk for this to occur and has low toxicity is especially gratifying.”
Gu is a professor of bioengineering and a member of the UCLA Jonsson Comprehensive Cancer Center where the spray was developed.
Survival After Mesothelioma Surgery
Survival after mesothelioma surgery or any other kind of cancer operation often depends on keeping new tumors from growing. But Dr. Gu says one of the hallmarks of cancer is that it comes back over and over.
When malignant mesothelioma cells begin to grow back after surgery, they have another chance to spread to other parts of the body. Dr. Gu calls this “one of the greatest obstacles in curing cancer.”
For people with peritoneal mesothelioma, surgeons often try to kill leftover cancer cells with a rinse of heated chemotherapy drugs. But this technique is not yet perfected for people with pleural mesothelioma.
Because it can be sprayed in a very specific area, the new spray-on gel may offer a way to improve survival after mesothelioma surgery for people with the pleural form.
Spray-On Immune-Boosting Drugs
The sprayable gel contains tiny pieces of calcium carbonate. Calcium carbonate is the primary component in egg shells. It is also used in antacids.
The UCLA scientists loaded the calcium carbonate particles with an immunotherapy drug. The drug keeps cancer cells from releasing a protein called CD47. CD47 is a protein these cells need to protect themselves from the immune system.
When cancer cells can no longer hide, their chances of survival after mesothelioma surgery go down. Dead or dying cancer cells are not able to seed new tumors.
Spray Produces Impressive Survival Results
Half of the lab mice that had the spray treatment lived for at least 60 days after surgery with no cancer regrowth. Not only did tumors not grow back in their original spot, but they did not grow in other spots either.
“We also learned that the gel could activate T cells in the immune system to get them to work together as another line of attack against lingering cancer cells,” says study author Qian Chen, a researcher in Gu’s lab.
The scientists say the immunotherapy gel even helps with wound healing.
More animal testing will have to happen to determine the right dose of the gel before human tests can start.
Survival after mesothelioma surgery is highest in younger patients and in those who were healthy to start with. Most surgeons now prefer the lung-sparing mesothelioma surgery over the more radical EPP surgery.
Chen, Q, et al, “In situ sprayed bioresponsive immunotherapeutic gel for post-surgical cancer treatment”, December 10, 2018, Nature Nanotechnology, https://www.nature.com/articles/s41565-018-0319-4
Gu, Zhen, “Sprayable gel could help the body fight off cancer after surgery”, December 10, 2018, https://cancer.ucla.edu/Home/Components/News/News/1230/1631