Cancer cells steal power from the immune cells sent to kill them

A team at Brigham and Women's Hospital and Harvard Medical School found that cancer cells grow thin physical tubes into nearby T cells and pull their mitochondria through, siphoning the very power supply the immune cells need to fight back.

Under the microscope, the researchers watched fluorescently labeled mitochondria move from T cells into cancer cells through these tunneling nanotubes, mostly in one direction. The transfer left the T cells depleted of energy while the cancer cells grew better fueled, and partly blocking tube formation cut the transfer and protected the T cells.

In mice with breast cancer, combining that nanotube blocker with an existing immune checkpoint drug slowed tumor growth more than either treatment alone. The result reframes some tumors as active parasites on the immune system rather than passive targets of it, though the work was mostly in cells and mice, with a small test on three human tumor samples.

The tumor runs on a stolen battery.