TAIPEI (Taiwan News) — A study by Chang Gung Memorial Hospital has discovered that removing the amino acid asparagine from immune cells can significantly enhance their cancer-fighting ability, improving the effectiveness of immunotherapy.
The research, published in the journal Nature Metabolism, in March, is among the first to apply immunometabolism in clinical treatment, the hospital stated. Immunotherapy works by extracting a patient’s immune cells, cultivating them in large numbers, and reinfusing them into the body to combat cancer, according to Taipei Medical University Hospital.
The killer T cell is a key immune cell. Originating from the thymus, it plays a crucial role in eliminating infected or cancerous cells, according to the US NIH.
The CGMH study found that depriving immune cells of asparagine, an essential nutrient that cancer cells aggressively compete for, can make these immune cells stronger and more efficient in attacking cancer cells. The team found that removing asparagine from killer T cells led to a tenfold increase in the release of anti-tumor proteins, enhancing the body’s ability to fight tumors, per CNA.
Since it is challenging to remove specific amino acids such as asparagine from a patient’s diet, the researchers turned to an alternative approach. They used L-asparaginase, a drug that creates an asparagine-deficient environment, to boost immune cell strength.
This method was combined with an immune checkpoint inhibitor, PD-1. PD-1 is a popular cancer immunotherapy drug that helps overcome tumor cells' ability to evade the immune system, according to the Development Center for Biotechnology.
In animal trials, this combination resulted in a significant reduction in tumor size. The team then tested this therapy on six advanced nasopharyngeal cancer patients who had previously undergone chemotherapy and immunotherapy with limited success.
Four out of the six patients showed a dramatic reduction in tumor size, and one was maintained in stable condition. Furthermore, a 57-year-old patient with metastatic cancer in the liver and lung saw rapid tumor shrinkage with the tumors ultimately vanishing entirely.
The study was focused on nasopharyngeal cancer since advanced cases typically have poor responses to immunotherapy. This promising result has raised hopes for a new treatment strategy for cancers resistant to traditional therapies.
CGMH Linkou Clinical Trial Center Director Lin Yung-chang (林永昌) said the research is still in its clinical trial phase. Though L-asparaginase is an approved drug, it can cause side effects such as fatigue, pain, and in rare cases, anaphylactic shock.
The team plans to expand the trials and further investigate whether the strategy can be applied to other tumors like lung cancer and breast cancer.