Nanoparticles Engineered to Boost Immune System’s Tumor Response

Specially coated nanoparticles may help boost the immune system’s defenses against tumors, according to a new study.

The technique boosts what is known as the abscopal effect, which is a response occasionally seen in cancer patients receiving localized radiation. In rare cases, a person with metastatic cancer will see a shrinking or disappearance of their cancer body-wide after radiation treatment on a single tumor. This occurs because irradiated tumor cells release a cascade of pro-inflammatory molecules and cancer-specific proteins that can trigger the immune system to hunt down the same types of proteins elsewhere.

Radiation therapy is already often coupled with immunotherapy meant to block molecules that would otherwise shut down the body’s immune response. Immunotherapy boosts the abscopal effect, says Andrew Wang, associate professor of radiation oncology and adjunct associate professor of biomedical engineering at the Univ. of North Carolina at Chapel Hill. Still, Wang says, the abscopal effect remains unusual.

“We want people to have an immune response against their cancer, and to keep that cancer down for many, many years,” he says.

To trigger an immune attack, specific immune cells called dendritic cells must detect the cancer-specific proteins and present them to T cells, which use them as a template for the kind of cells they must hunt down and destroy. But dendritic cells are not naturally attuned to free-floating proteins, Wang says — after all, the body is full of them under normal (noncancer) conditions.

So Wang and his team decided to try to boost the dendritic cell response to the proteins...