Cancer Biology
Supercharged Immune Cells Keep Cancer in its Place
Using nanotechnology, scientists armed the body’s own natural killer cells to prevent cancer metastasis in mice. Read more…
Normal, unenhanced natural killer (NK) cells wait for cancer cells in lymph nodes, one of the first sites the migrants land. They use a surface protein called TRAIL to grab onto receptors on the cancer cells’ surface and induce apoptosis. But cancer fights back with secreted molecules that keep NK cells weak, so they often don’t have enough TRAIL to go in for the kill. Scientists have tried injecting people with TRAIL alone, but it quickly clears from the bloodstream and has little effect.To overcome this, King’s team turned to liposomes, which last longer in the bloodstream than individual proteins and are safe and easily degraded. The researchers attached TRAIL and an antibody that recognizes NK cells to a lipid balloon 100–150 nanometers wide. To test these would-be assassins, King and colleagues injected mice under the skin with human colon cancer cells carrying the luciferase gene so that they could track progression of the glowing, growing tumor. Two weeks later, the authors started a month-long TRAIL balloon treatment test. In control mice, the cancer cells infiltrated nearby lymph nodes, but in treated mice, the nodes stayed clear.
“We’re very excited that we can prevent the spread of this tumor to the lymph nodes,” King said. As a bonus, the original tumors in the treated mice shrank a bit. “It was a nice surprise to see just how effective it was even treating the primary tumor.”
King envisions TRAIL liposomes as a treatment in concert with medications that target solid tumors, which would be a significant advance since no such anti-metastasis treatment exists today.
Reference
Chandrasekaran S et al. Super natural killer cells that target metastases in the tumor draining lymph nodes. Biomaterials. 2 Nov 2015; 77: 66-76.