Injections of drug-loaded sticky nanoparticles could shrink skin cancer

Injections of drug-loaded stic...
Bioadhesive nanoparticles (white) stick to skin cancer cells in a lab dish
Bioadhesive nanoparticles (white) stick to skin cancer cells in a lab dish
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Bioadhesive nanoparticles (white) stick to skin cancer cells in a lab dish
Bioadhesive nanoparticles (white) stick to skin cancer cells in a lab dish

Researchers at Yale University have shown how skin cancer could one day be treated with a simple injection. The team found that they could shrink tumors by injecting them with adhesive nanoparticles loaded with chemotherapy drugs.

Being located on the outside of the body, skin cancer is uniquely positioned for less invasive therapies. Recent research has tried to treat these tumors using magnetic bandages that heat up to kill cancer, or chemotherapy hydrogels that could be rubbed into the skin, with both returning promising results in tests on mice.

In the new study, the Yale team investigated injections as a treatment for skin cancers, specifically squamous cell carcinomas. The active ingredient is a chemotherapy agent called camptothecin, and in order to get it to stick around long enough to be effective, the team encased it inside nanoparticles designed to be “bioadhesive,” meaning they bind to cancer cells.

“When you inject our nanoparticles into a tumor, it turns out that they’re retained within that tumor very well,” says Mark Saltzman, co-author of the study. “They accumulate and bind to the tumor matrix, so one single injection lasts for a very long time – the particles stay there and slowly release the compounds. You need that to get rid of the lesion.”

The team tested the technique in mice with squamous cell carcinomas. They injected the animals with camptothecin – one group receiving the drug by itself, and the other having it delivered in nanoparticles. After 10 days, they found that in the group that received nanoparticle treatment, 50 percent of the drug was retained in the tumor cells. Meanwhile, they were unable to detect the drug at all in the group that received it alone.

Perhaps unsurprisingly, the tumors shrank more significantly in the nanoparticle group – in fact, they disappeared entirely in around 20 percent of the treated mice.

In further experiments, the researchers combined the treatment with another agent that stimulates the body’s immune system to help fight off the remaining cancer cells. Mice treated with this one-two punch survived for longer than the control group.

“I call the phenomenon ‘kill and thrill,'” says Michael Girardi, senior author of the study. “You don't want to just kill the cells and leave them there, you want to stimulate the immune system to clean up the mess and also react against cells that might not have been killed directly. So it’s a two-pronged attack on the cancer.”

The team says that ideally, this technique could reduce the need for surgical removal of skin cancers or system-wide chemotherapy treatments. Instead, patients might only need to go to a dermatologist and receive a single injection.

Of course, there’s still a long way to go before that could ever happen. For now, the team plans to continue development with an eye towards eventual clinical trials.

The research was published in the journal Proceedings of the National Academy of Sciences.

Source: Yale University

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