Australian researchers have made a breakthrough in the fight
against cancer and are working to find a way to get the
body's natural killer cells to eliminate cancerous cells.
Researchers at Melbourne's Peter MacCallum Cancer Centre have
discovered a new molecule that a cancer cell can produce on
its surface to convince the body's natural killer cells it
poses no danger.
The research team, led by Dr Dan Andrews and Professor Mark
Smyth from the Cellular Immunology Laboratory at the centre,
says the cancer cells fool the body's natural immune defences
into ignoring their threat.
Dr Andrews said the discovery would open the door to the
development of new treatments to interrupt this deception.
The findings were published overnight in the prestigious
scientific journal Nature Immunology.
Dr Andrews says each natural killer cell is part of a roving
biological security team, performing sweeping scans by
temporarily binding one of its receptors to a corresponding
molecule on every cell's surface, like a key into a lock.
"When a cell becomes infected or damaged, it loses these
surface molecules; when a natural killer cell cannot find a
lock to bind to, it recognises that cell as a threat and
destroys it," he says.
Researchers from around the world have been hunting for each
lock to correspond to the 10 identified natural killer cell
surface keys, but only investigating the MHC-I class of
molecule, or classical MHC-I.
The lock Dr Andrews and his team have discovered, called
H2-M3, is a non-classical MHC-I molecule.
"Now we have identified the role H2-M3 plays in cancer
growth, we can learn more about how it binds to natural
killer cell receptors and plan new therapies to specifically
target these types of interactions," Dr Andrews said.
"Blocking this exchange could prevent natural killer cells
from binding to cancerous cells and accepting them as
harmless, instead prompting the natural killer cells to
recognise and destroy them efficiently, as they would any
other disease, invading virus or bacteria."
Dr Andrews said that understanding how natural killer cells
recognise the H2-M3 lock is a huge step forward in the
journey toward new immunotherapies for patients.
"Although these are early days, it is very exciting to make
discoveries that may very well result in new ways to help a
patient's immune system fight cancer," he said.
"Right now, we have one more molecule to work on, and the
possibility of many more tomorrow."