A polymer implant signals cells to combat cancer.
Source: “Infection-Mimicking Materials to Program Dendritic Cells In Situ”
David Mooney et al.
Nature Materials 8: 151-158
Results: A new implant attracts immune cells and exposes them to molecules that stimulate them to attack cancerous tumors. When tested in mice that normally die of cancer within 25 days, the implants allowed 90 percent of the mice to survive. Similar experimental therapies based on transplanting immune cells are only about 60 percent effective.
Why it matters: The implants could eventually be used to treat human cancers that don’t respond to other therapies, and they could also be used to treat immune disorders such as type 1 diabetes and arthritis. Other approaches that involve stimulating immune cells haven’t proved successful in clinical trials. Those techniques require the cells to be removed from the body and then reimplanted; many are damaged in the process and die, while survivors often fail to trigger attacks on cancerous tumors. The new implant stimulates cells inside the body, without subjecting them to stressful procedures.
Methods: The spongelike implant is made of a biodegradable polymer that releases chemical signals called cytokines. In mice with melanoma, these signals attract immune cells called dendritic cells to the nooks and crannies of the implant. There the cells are exposed to a cancer antigen that stimulates them to attack tumors. When tissues from the mice were analyzed, the researchers found that dendritic cells had migrated to the lymph nodes and activated other immune cells, and the animals’ tumors had shrunk.
Next steps: Before proceeding to clinical trials, the implants must pass safety tests in large animals. Long-term studies will then establish whether the immune system will attack cancer that may recur years after the implant has degraded.