To grow and spread, cancer cells must evade the immune system. Investigators from Brigham and Women’s Hospital and MIT used the power of nanotechnology to discover a new way that cancer can disarm its would-be cellular attackers by extending out nanoscale tentacles that can reach into an immune cell and pull out its powerpack. Slurping out the immune cell’s mitochondria powers up the cancer cell and depletes the immune cell. The new findings, published in Nature Nanotechnology, could lead to new targets for developing the next generation of immunotherapy against cancer.
“Cancer kills when the immune system is suppressed and cancer cells are able to metastasize, and it appears that nanotubes can help them do both,” said corresponding author Shiladitya Sengupta, PhD, co-director of the Brigham’s Center for Engineered Therapeutics. “This is a completely new mechanism by which cancer cells evade the immune system and it gives us a new target to go after.”
To investigate how cancer cells and immune cells interact at the nanoscale level, Sengupta and colleagues set up experiments in which they co-cultured breast cancer cells and immune cells, such as T cells. Using field-emission scanning electron microscopy, they caught a glimpse of something unusual: Cancer cells and immune cells appeared to be physically connected by tiny tendrils, with widths mostly in the 100-1000 nanometer range. (For comparison, a human hair is approximately 80,000 to 100,000 nanometers). In some cases, the nanotubes came together to form thicker tubes. The team then stained mitochondria — which provide energy for cells — from the T cells with a fluorescent dye and watched as bright green mitochondria were pulled out of the immune cells, through the nanotubes, and into the cancer cells.