(September 6, 2015) Giving
cancer patients aspirin at the same time as immunotherapy could dramatically
boost the effectiveness of the treatment, according to new research published
in the journal Cell today (Thursday).
Francis Crick Institute researchers, funded by Cancer
Research UK, have shown that skin, breast and bowel cancer cells often produce
large amounts of prostaglandin E2 (PGE2). This molecule dampens down the immune
system's normal response to attack faulty cells, which helps cancer to hide. It
is a trick that allows the tumour to thrive and may explain why some
immunotherapy treatments have not been as effective as hoped.
Aspirin is part of a group of molecules called COX inhibitors,
which stop the production of PGE2 and help reawaken the immune system.
Combining immunotherapy with aspirin or other COX inhibitors substantially
slowed bowel and melanoma skin cancer growth in mice, compared to immunotherapy
alone*.
Study author Professor Caetano Reis e Sousa, senior group
leader at the Francis Crick Institute, said: "We've added to the growing
evidence that some cancers produce PGE2 as a way of escaping the immune system.
If you can take away cancer cells' ability to make PGE2 you effectively lift
this protective barrier and unleash the full power of the immune system.