Cutting out certain amino acids - the building blocks of
proteins - from the diet of mice slows growth of some tumours and
prolongs survival, according to new research published in the
science journal Nature.
The scientists found that removing two non-essential amino acids
- serine and glycine - from the diet of mice slowed the development
of lymphoma and intestinal cancer.
The researchers also found that the special diet made some
cancer cells more susceptible to chemicals in cells called reactive
oxygen species.
Chemotherapy and radiotherapy boost levels of these chemicals in
the cells, so this research suggests a specially formulated diet
could make conventional cancer treatments more effective.
Professor Karen Vousden, who recently moved to the Francis Crick
Institute in London, led the work at the Cancer Research UK Beatson
Institute and the University of Glasgow.
The next stage would be to set up clinical trials with cancer
patients to assess the feasibility and safety of such a
treatment.
Dr Oliver Maddocks, a Cancer Research UK scientist at the
University of Glasgow, said: "Our findings suggest that restricting
specific amino acids through a controlled diet plan could be an
additional part of treatment for some cancer patients in future,
helping to make other treatments more effective.
Professor Vousden, Cancer Research UK's chief scientist, said:
"This kind of restricted diet would be a short term measure and
must be carefully controlled and monitored by doctors for safety.
Our diet is complex and protein - the main source of all amino
acids - is vital for our health and well-being. This means that
patients cannot safely cut out these specific amino acids simply by
following some form of home-made diet."
Amino acids are the building blocks that cells need to make
proteins. While healthy cells are able to make sufficient serine
and glycine, cancer cells are much more dependent on getting these
vital amino acids from the diet.
However, the study also found that the diet was less effective
in tumours with an activated Kras gene, such as most pancreatic
cancer, because the faulty gene boosted the ability of the cancer
cells to make their own serine and glycine. This could help to
select which tumours could be best targeted by diet therapy.
Dr Emma Smith, science communication manager at Cancer Research
UK, said: "This is a really interesting look at how cutting off the
supply of nutrients essential to cancer cell growth and division
could help restrain tumours.
"The next steps are clinical trials in people to see if giving a
specialised diet that lacks these amino acids is safe and helps
slow tumour growth as seen in mice. We'd also need to work out
which patients are most likely to benefit, depending on the
characteristics of their cancer."
The paper, Modulating the therapeutic response of tumours to
serine and glycine starvation, is published inNature.
This research was funded by Cancer Research UK and the European
Research Council.