By removing certain amino acids from the diets fed to rodents suffering from a deadly form of brain cancer known as glioblastoma, researchers found that destructive cells began dying through a process called ferroptosis. What's more, the mice that were put on the restrictive diets were also more receptive to drugs that triggered the same type of cancer cell death, making the findings a potential source of inquiry for fighting the disease in humans.
Cell death inside our bodies is a normal part of how we function. Typically, through a process known as apoptosis, cells that are abnormal or simply no longer needed are dismantled and reabsorbed. However, this process can be blocked in cancer cells, so the body has a harder time getting rid of them, which allows them to multiply and cause serious threats to our health. Ferroptosis is another type of cell death that was discovered relatively recently in which iron plays a key role. Its activation has previously been linked to a possible way to fight cancer.
In a new study, a research team from the University of North Carolina School of Medicine (UNC) and Columbia University discovered that the cells involved in forming glioblastoma are particularly subject to death by ferroptosis. The finding is significant because glioblastoma has a 100% fatality rate with no known cures. It is also a fast-moving cancer with a median survival period of just 16 months.
In their study, the team fed mice a diet that restricted the intake of cysteine and methionine, two sulfur amino acids whose restriction has previously been linked to ferroptosis and cancer cell death in lung and pancreatic cancer as well as sarcomas. Not only did they find that the diet made glioblastoma cells more likely to die from ferroptosis, but they also noted that the cells become more subject to chemotherapy drugs, meaning that they could be delivered in lower doses. All of the mice on the special diet had improved survival periods than those on a control diet, and the mice that were on a combined diet and chemotherapy regimen fared the best.
Cysteine is prominent in whole grains, beef, eggs, and poultry, while foods high in methionine include brazil nuts, fish, and pork as well as beef, eggs, and poultry. It's unclear whether human glioblastoma patients on a diet that restricts these amino acids would fare as well as the mice did in the study, but UNC lead researcher Dominique Higgins plans to find out.
"Now, we need to find a way to eliminate those components (cysteine and methionine) through dietary needs, while still maintaining energetic requirements that a patient may have, especially a cancer patient, who has different requirements than the average patient,” said Higgins.
He is working with colleagues to design a human study in which glioblastoma patients are put on the restricted diet prior to tumor-removal surgery. After the surgery, the researchers will analyze the tumors to see what effect the diet had.
The research has been published in the journal, Nature Communications.
Source: UNC Health