Researchers turn deadly leukemia cells into immune cells

A team of researchers at Stanford's School of Medicine has uncovered a potent new treatment method for combating a deadly form of leukemia.

While survival rates for B-cell acute lymphoblastic leukemia, a particularly nasty form of white blood cell cancer, had increased to around 85 per cent over the past decade thanks to the advent of stem cell therapies, the prognosis for this disease in the presence of a Philadelphia chromosome mutation continued to be poor.

However, thanks to a chance observation by Dr Scott McClellan, the Stanford team believes it had figured out way to neutralise the disease using its own cancerous cells against it.

The research effort started when, McClellan noticed that a number of leukemic cells had transformed from cancerous cells into "mature" harmless immune cells known as macrophages.

These immune cells, in addition to directly consuming cellular debris, pathogens and cancers also recruit other immune cells for the fight. "B-cell leukemia cells are in many ways progenitor cells that are forced to stay in an immature state," Dr Ravi Majeti, an assistant professor of medicine at Stanford, said in a statement.

However, with the addition of various transcription factors -- proteins capable of latching onto and activating specific DNA sequences -- Majeti and McClellan, in a way, forced these deadly cancer cells to "grow up" into fully formed macrophages.

Further, the researchers discovered that the process not only neutralised that specific cancer cell, but also instigated the newly-made macrophage to start digesting the cancerous plague and call in the rest of the immune system to actively fight the mutation.

While trying to keep alive leukaemia cells from a patient in a culture plate, McClellan observed that some of the cancer cells in culture were changing shape and size into what looked like harmless immune cells or macrophages.

Majeti agreed with the observation, but the change was baffling. Majeti then recalled an old research paper, which showed that early B-cell mouse progenitor cells could be forced to become macrophages when exposed to certain transcription factors - proteins that bind to certain DNA sequences.

Majeti, McClellan and Christopher Dove, an MD / PhD student, conducted more experiments and confirmed that methods shown to have altered the fate of the mouse progenitor cells years ago could be used to transform these human cancer cells into macrophages, which could engulf and digest cancer cells and pathogens.

The journal Proceedings of the National Academy of Sciences has published the study.