I love the name for stem cells in Spanish, células madre, or mother cell. It seems appropriate that the sons and daughters of our stem cells send a warning to mom to protect herself when they are under attack. Specifically, a team at the University of Washington reported Monday in Nature Communications, that when cells die from radiation or chemotherapy, they send a chemical signal that causes the nearby stem cells to flip a genetic switch that prevents them from dying.
This ability helps our bodies recover from cancer treatment, but it could also be one reason so many cancers return. While we want our normal stem cells to retain the ability to replace damaged tissue, that benefit may come with an unwanted corollary. The closely related cancer stem cells that can generate new tumors may have the same ability.
The researchers found that dying cells release a protein that binds to a receptor on the surface of stem cells. That in turn triggers the stem cells to produce a genetic tool that switches off a key gene that would normally tell the stem cells to die because of damage to their DNA caused by the therapy.
Having survived the programmed cell death normally triggered by DNA damage, the stem cells have time to repair their DNA and go on to reproduce healthy tissue. This pathway—the protein released by the dying cell to the genetic switch in the stem cell—could also become a target for cancer therapy. It could provide a way to prevent the cancer-initiating stem cell from surviving the chemotherapy or radiation.
A press release from the university quoted one of the researchers on the therapeutic potential:
“There are very similar genes and proteins in human cancers that are likely playing the same role of protecting the tumor-initiating cells from destruction. As a result, the tumor-initiating cells survive and the cancers return. By targeting these factors, perhaps by blocking [the stem cell surface] receptors, it may be possible to block the protective signal from the daughter cells, and thereby allow programmed cell death to proceed in the [cancer] stem cells and prevent cancer.”