Stanford researchers change cancer cells into immune cells

An almost accidental discovery at a laboratory in Stanford University, California, has raised hopes of finding alternative therapies to cure a type of blood cancer by turning the dangerous cells into white blood cells, the "good guys."

These immune cells are also able to detect and destroy other cancer cells, therefore providing a fighting chance against one of the most aggressive blood cancers, B-cell acute lymphoblastic leukemia with a mutation called the Philadelphia chromosome.

The Stanford researchers are particularly excited about the prospects of the discovery since this kind of leukemia often has a grim outcome for most patients.

Professor Ravi Majeti and his team, whose findings are described in a paper in the latest issue of Proceedings of the National Academy of Sciences published on Monday, claimed the discovery was done almost by chance after they collected the type of leukemia cells from a patient.

"We were trying to keep these cells alive by providing them with different kinds of nutrients and growth factors," Majeti told Xinhua. "And we saw that sometimes, they shifted to white blood cells, also known as macrophages. Instead of ignoring this fact, we decided to investigate what was making them change."

Majeti and his team were at odds to find the reason for the change until one researcher remembered an earlier study which showed that early B-cell mouse progenitor cells could be forced to become macrophages when exposed to certain transcription factors.

This meant that the main cause of the metamorphosis was a cocktail of proteins that bind to certain DNA sequences, turning the dangerous cells into macrophages that worked like "hound dogs" to track and kill cancer cells.

These leukemia cells not only turned into white blood cells, which are used by the immune system to fight all kinds of pathogens. They actually found the cancer cells and eliminated them by following their chemical trace.

Other treatments like chemotherapy also stimulate the immune system to track and destroy cancer cells, Majeti said, "but we have managed to find a way to actually turn the bad guys into good guys."

Reprogramming cancer cells to turn into immune cells can be a new strategy to treat leukemia, but Majeti warned that it can take years to develop a specific drug.

"So far we have done these trials in-vitro, we still have to try it on an animal model, on mice. Then, after that, we would start with clinical trials on humans," he said, adding that the team's current work is preliminary.

A similar treatment for another kind of blood cancer is being used nowadays with retinoic acid, to turn acute promyelocytic leukemia cells into mature cells known as granulocytes.

It is the only well-established therapy that matures -- or "differentiates" -- cancer cells, but researchers around the world are hopeful of finding many more.

"There's big-time interest in differentiation therapies for cancer," Majeti said. Endit