Diet Lacking 2 Amino Acids Slows Tumor Growth, Prolongs Survival

Cutting supply of essential nutrients restrains tumors.

Cutting 2 non-essential amino acids from the diet of mice slowed tumor growth and prolonged survival, according to a study published in Nature.

Normally, healthy cells can make sufficient serine and glycine amino acids—–the building blocks of proteins. But cancer cells rely more on getting vital amino acids from the diet.

“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 the future, helping to make other treatments more effective,” said investigator Dr Oliver Maddocks.

The investigators also found that the special diet that removed serine and glycine made some cancer cells more susceptible to reactive oxygen species.

Since both chemotherapy and radiotherapy boost these chemical levels in the cells, the findings suggest a specially formulated diet could improve the efficacy of conventional cancer treatments.

“This kind of restricted diet would be a short-term measure and must be carefully controlled and monitored by doctors for safety,” said co-author Karen Vousden. “Our diet is complex and protein—–the main source of all amino acids––is vital for our health and wellbeing. This means that patients cannot safely cut out these specific amino acids simply by following some form of home-made diet.”

Additionally, the investigators found that the diet had a lower efficacy in tumors with an activated Kras gene, such as pancreatic cancer. This is because the faulty gene boosted the cancer cells’ ability to produce their own serine and glycine. The authors noted that this could help identify which tumors would benefit most by diet therapy.

“This is a really interesting look at how cutting off the supply of nutrients essential to cancer cell growth and division could help restrain tumors,” Said Dr Emma Smith, science communication manager, Cancer Research UK. “The next steps are clinical trials in people to see if giving a specialized diet that lacks these amino acids is safe and helps slow tumor 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.”