“Our results suggest that a dietary intervention can increase the effectiveness of a targeted cancer therapy,” said the study’s senior author Vincent Cryns, professor of medicine at the University of Wisconsin School of Medicine and Public Health in the US.
Methionine is an essential amino acid abundant in meat, fish, some legumes and nuts, but low in fruits and vegetables.
Patients with triple-negative breast cancer have limited treatment options because their tumor cells lack the three receptors, estrogen, progesterone and human epidermal growth factor receptor 2 (HER-2), commonly targeted in hormone or chemotherapy.
The study was detailed in the journal Clinical Cancer Research.
Scientists knew that methionine deficiency can block the growth of many types of cancer, but the underlying mechanisms have puzzled researchers.
“We have shown that removing methionine can have a specific effect on a molecular pathway that regulates cell death to increase the vulnerability of cancer cells to treatments that target this pathway,” Cryns said.
Specifically, the researchers showed that when triple-negative breast cancer cells were deprived of methionine, the stressed cancer cells responded by increasing the amount of a receptor on the cell’s surface called TRAIL-R2.
This resulted in the breast cancer cells becoming very sensitive to an antibody that binds to TRAIL-R2 on the surface of the cancer cells and triggers them to die.
The study lays the foundation for a clinical trial to see if a low-methionine diet will help improve outcomes in women with “triple-negative” breast cancer.