Leukemia, a group of cancers affecting the bone marrow and blood, is notoriously difficult to treat, often relapsing and becoming resistant to treatment. But a new study, published in the Proceedings of the National Academy of Sciences, could offer hope, revealing that it's possible to make leukemia cells kill each other.
More accurately, the researchers from The Scripps Research Institute (TSRI) have construed a technique that convinces the leukemia cells to transform into leukemia-killing immune cells, rewriting their biological programming. The key, so to speak, is an extremely rare human antibody. But where did the researchers find it, and how does it work?
Antibodies are proteins produced naturally by the human body’s immune system. They act as the “handcuffs” to the white blood cells’ “police,” sticking to foreign invaders like microbes and either directly neutralizing them or tagging them for destruction.
Recently, the scientists were attempting to find antibody therapies to treat people with immune cell deficiencies in which the bone marrow doesn't produce enough white blood cells. They hoped that they could find antibodies that would activate receptors on immature bone marrow cells that would cause them to change into mature cells. Over the last few years, they have succeeded in doing this. What they didn’t expect to see, however, was that a handful of these growth-induced antibodies turn immature bone marrow cells into completely different types, such as cells normally found in the nervous system.
Acute Myeloid Leukemia (AML) is a particularly aggressive type of leukemia that attacks myeloid cells in the body; these cells deal with bacterial infections, parasites and prevent the spread of tissue damage. Sufferers of AML produce far too many white blood cells in their bone marrow, which interferes with the normal production of other blood cell types.
The researchers flooded a human blood sample rich in dangerous AML cells with these growth-activating antibodies, and what they found was remarkable: the antibodies transformed the AML cells into dendritic cells, key support cells within the immune system. With longer exposure to the antibodies, these cells were matured even further into cells that resemble, and behave similarly to, cells that hunt down and kill threats in the body, including viruses, bacteria and cancer cells.
These “natural killer” (NK) cells showed the ability to extend their tendrils into their cancerous brethren, destroying 15% of them in one sample within a single day. Incredibly, these NK cells only seem to engage in fratricide, targeting only their former AML cell type, not other types of cancer cell.
The researchers hope that this technique – which they’ve called “fratricidin therapy” – can be used to transform a range of cancer cells into specific NK cells in order to actually cure a patient of their cancer altogether.