A group of researchers from UCLA have developed a spray gel that contains immune-stimulating drugs. The gel was effective about 50 percent of the time in stimulating laboratory animals’ immune systems to stop cancer from recurring and inhibiting its metastases.
Despite the best efforts of oncologists and surgeons, cancer sometimes comes back after surgery. And surgery is a common treatment for some types of cancer. For example, about 95 percent of early-diagnosed breast cancer requires surgery. It is also often the first line of treatment for brain tumors.
A group of researchers with University of California, Los Angeles (UCLA) have developed a spray gel that contains immune-stimulating drugs. In a study published in the journal Nature Nanotechnology, the gel was effective about 50 percent of the time in stimulating laboratory animals’ immune systems to stop cancer from recurring and inhibiting its metastases.
“This sprayable gel shows promise against one of the greatest obstacles in curing cancer,” stated lead researcher Zhen Gu, professor of bioengineering at the UCLA Samueli School of Engineering and member of the Jonsson Comprehensive Cancer Center. “One of the trademarks of cancer is that it spreads. In fact, around 90 percent of people with cancerous tumors end up dying because of tumor recurrence or metastasis. Being able to develop something that helps lower this risk for this to occur and has low toxicity is especially gratifying.”
Zhen Gu tested the gel in mice that had advanced melanoma tumors surgically removed. The gel cut the growth of the tumors that remained post-surgery, which led to lower recurrences. After treatment, 50 percent of the mice survived for at least 60 days without tumor regrowth.
The spray gel inhibited recurrence in the area of the body where the tumor was removed, but also in other parts of the body.
The gel isn’t yet ready for human testing. The active ingredient used was an antibody designed to block CD47. In other words, the gel used a checkpoint inhibitor loaded into nanoparticles. The nanoparticles were constructed of calcium carbonate, the primary component of egg shells and in rocks. Calcium carbonate gradually dissolves in surgical wound sites, which are slightly acidic. Calcium carbonate also stimulates the activity of a macrophage that helps remove foreign invaders from the body.
Qian Chen, lead author of the study and a postdoctoral researcher in Zhen Gu’s laboratory, stated, “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.”
The researchers will continue to test the gel in animals to determine optimal dosing, appropriate treatment frequency, and the best combination of nanoparticles before it can be tested on human patients.
Other researchers participated from the University of North Carolina, Chapel Hill; National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou; and the School of Pharmacy, Fudan University, Shanghai.
Earlier this year, researchers at the Dana-Farber Cancer Institute, working on mice, implanted a tiny disc of gel during surgery that slowly released an immune-stimulating drug. This too appeared to prevent cancer from recurring.
The research was conducted on more than a hundred mice with breast cancer, lung cancer or melanoma. After removing the cancers surgically, they inserted the disc, about the size of a dime.
In an interview with WBUR Public Radio, senior author Michael Goldberg, said, “Cancer immunotherapy can confer durable survival benefit, but the percentage of patients who respond to this approach remains modest. We optimized the formulation of a biodegradable hydrogel that can concentrate drugs that boost immune cells at a site of interest and release these drugs over an extended period of time.”
In the mice with breast cancer, they found a durable survival benefit among 65 percent of treated mice. In the mice without the disc but only surgery, the durable survival benefit was about 10 percent.
