Taming leukemia cells

Illustration of an unhappy cell

After a chance observation in the lab, Stanford scientists found a method that can force dangerous leukemia cells to mature into harmless immune cells called macrophages.

Ravi Majeti, MD, PhD, an assistant professor of medicine, and colleagues made the key observation after collecting cells from a patient with a type of B-cell acute lymphoblastic leukemia. The disease is a particularly aggressive form of leukemia, and any new treatment would be an exciting development.

The researchers were trying to keep the cells alive in a culture plate — “We were throwing everything at them to help them survive,” says Majeti — when postdoctoral researcher Scott McClellan, MD, PhD, noticed that some of the cells were changing into what looked like macrophages. Then Majeti remembered an old research paper showing that early B-cell mouse progenitor cells could be forced to become macrophages when exposed to certain proteins.

So the researchers conducted some experiments and saw that the methods also worked for human cells: They transformed the cancer cells into macrophages.

Since macrophages can engulf and digest cancer cells, the hope is that transforming cancer cells will not only neutralize them, but also turn them into cancer-fighting agents. “Because the macrophage cells came from the cancer cells, they will already carry with them the chemical signals that will identify the cancer cells, making an immune attack against the cancer more likely,” says Majeti, lead author of a paper published in the Proceedings of the National Academy of Sciences.