When pulling an all-nighter to meet an important deadline, there’s nothing like a cup of coffee for a much-needed boost of energy. Just like us, our immune cells work overtime too. Natural killer (NK) cells, for example, are on round-the-clock surveillance, looking to eliminate cancer or virus-infected cells. But how do these cells fuel themselves for all this hard work?
Deciphering the secrets of NK cell metabolism is a first step towards leveraging their power as cancer immunotherapies, said Kong-Peng Lam, Executive Director of A*STAR’s Singapore Immunology Network (SIgN).
“NK cell-based immunotherapy has several advantages over T cell therapies,” Lam explained. “They are safer and can be developed into off-the-shelf therapeutics to treat cancer patients.”
Work by Lam and Shengli Xu from SIgN aimed to advance previous studies that showed how immune cells process energy is tightly linked to their cancer-killing capabilities. The team focused on an immune-stimulating protein called interleukin (IL)-10, investigating its influence on NK cell metabolism in human cell-based assays.
The researchers discovered that contact with IL-10 turned the dial-up on two distinct metabolic pathways in NK cells—glycolysis and oxidative phosphorylation. Interestingly, this metabolic shift seemed to flip the switch on NK cells, turning them into potent cancer killers.
These results suggest that using IL-10 and other approaches to trigger this metabolic shift in NK cells could one day give patients the upper hand in their battle against cancer. However, scientists first need to figure out how to overcome the technical limitations of using live NK cells as cancer treatments in the clinic.
“Clinical-scale expansion of NK cells ex vivo is difficult,” explained Lam. “NK cells can also lose viability and activity during the freeze-thaw process.” Ongoing work by Lam and others in the field is helping to rise above these barriers, including developing strategies to maintain NK cell potency in the harsh, immune-suppressive tumour microenvironment.
The researchers remain spurred on by exciting results from experimental NK therapies in human trials. “Currently, there are many clinical trials on allogeneic NK or chimeric antigen receptor-transduced (CAR-NK) cells to treat patients with solid tumours, such as neuroblastoma, ovarian cancer, breast cancer and gastric cancer. Some of these have yielded promising results,” concluded Lam.