A new form of treatment using microneedle technology has the potential to kill melanoma skin cancer more effectively, a new study reports.
For this study, biomedical engineering scientists at North Carolina State University and the University of North Carolina at Chapel Hill set out to find whether or not they can deliver cancer immunotherapy treatment directly to the site of the cancer, which would make treatment more effective.
In current immunotherapy research, researchers have been focused on using anti-PD-1 antibodies to stop cancer cells from binding a receptor onto T cells, which are cells from the immune system that are responsible for targeting and killing cancer. Once cancer cells bind to these T cells, however, they can no longer recognize the difference between cancerous and healthy cells, making it hard for the body to beat the cancer.
Although researchers know that using anti-PD-1 antibodies can help prevent cancer cells from tricking T cells, how these antibodies are administered can affect their effectiveness.
"First, the anti-PD-1 antibodies are usually injected into the bloodstream, so they cannot target the tumor site effectively. Second, the overdose of antibodies can cause side effects such as an autoimmune disorder," said Chao Wang, co-lead author of the study and a postdoctoral researcher in the joint biomedical engineering program at NC State and UNC-Chapel Hill.
To fix these problems, the researchers created a patch that contained microneedles made from hyaluronic acid. The researchers explained that ideally, once the patch was placed on top of the tumor site, the microneedles would help directly deliver the antibodies to the melanoma.
"This technique creates a steady, sustained release of antibodies directly into the tumor site; it is an efficient approach with enhanced retention of anti-PD-1 antibodies in the tumor microenvironment," said Zhen Gu, an assistant professor in the biomedical engineering program.
The researchers had tested the patch on animal models and found that 40 percent of the mice that were treated using this method survived and did not have any signs of the cancer after 40 days. The survival rate for the control group was at zero percent. After finding success with this method, the researchers tested out a patch with microneedles that contained the anti-PD-1 antibodies and another antibody called anti-CTLA-4.
"Using a combination of anti-PD-1 and anti-CTLA-4 in the microneedle patch, 70 percent of the mice survived and had no detectable melanoma after 40 days," Wang said.
"Because of the sustained and localized release manner, mediated by microneedles, we are able to achieve desirable therapeutic effects with a relatively low dosage, which reduces the risk of auto-immune disorders," Gu added. "We're excited about this technique, and are seeking funding to pursue further studies and potential clinical translation."
The study was published in the journal Nano Letters.
