Researchers have discovered how CD8+ T cells use the amino acid cysteine to balance two competing tasks: multiplying and killing cancer cells. The study, published in Cell, found that cysteine is split inside T cells between two pathways.
One pathway helps T cells grow by using cysteine to make iron-sulfur (FeS) clusters through the enzyme NFS1. This is critical for their long-term survival and ability to fight tumors. The other pathway makes glutathione, an antioxidant that protects cells but can limit their cancer-killing power. Blocking this pathway makes T cells more aggressive killers, though they stop dividing.
The findings suggest ways to fine-tune T cells for better cancer therapy. Boosting the FeS pathway while controlling glutathione production could create “super” T cells that both multiply and attack tumors effectively. Targeting these cysteine pathways offers a new approach for immunotherapy, helping T cells stay active longer and improving cancer treatment outcomes.