The immune system often can spot and destroy abnormal cells before they grow into cancer. Normally cancer tumour cells put up defences in order to block our immune system from attacking them. One way they do this is because tumours can grow so rapidly that they outpace their blood supply, creating a low-oxygen environment.
By maintaining low oxygen levels inside the tumour, this can increase the production of a molecule that blocks the tumour fighters that our immune system produces, called T cells. Lots of research is under way to develop drugs that could block the production of this molecule adenosine, but researchers at North Eastern University wondered whether adding oxygen to tumours could strip away that defence. So they put mice with lung tumours into chambers that let them breathe oxygen doses mimicking supplemental oxygen therapy doses.
The results showed that tumours shrank more in the high-oxygen group, and even more so when researchers also injected the mice with doses of extra T cells. With the extra oxygen, “you remove the brake pedal” that cancer can put on tumour-fighting immune cells, said Michail Sitkovsky, director of the New England Inflammation and Tissue Protection Institute at North Eastern University, who led the work. The extra oxygen changed the tumour’s environment so that immune cells could get inside and do their jobs.
The study has exciting potential but obviously it must be tested in people first. If it works then this supplemental oxygen approach could be utilised to work in conjunction with other cancer therapies to aid in the battle against cancer.