Scientists claim to have found that inhaling supplemental oxygen could awaken 'sleepy' tumour-fighting cells, a breakthrough that may dramatically improve cancer treatment.
Breathing in 40 to 60 per cent oxygen as opposed to the 21 per cent oxygen in air can weaken immunosuppression and awaken anti-tumour cells, researchers said.
The new approach, some 30 years in the making, could dramatically increase the survival rate of patients with cancer, which kills some 8 million people each year, they said.
Michail Sitkovsky, an immunophysiology researcher at Northeastern University in Boston, and his team found that supplemental oxygenation inhibits the hypoxia driven accumulation of adenosine in the tumour microenvironment and weakens immunosuppression.
This, in turn, could improve cancer immunotherapy and shrink tumours by unleashing anti-tumour T lymphocytes and natural killer cells.
"Breathing supplemental oxygen opens up the gates of the tumour fortress and wakes up 'sleepy' anti-tumour cells, enabling these soldiers to enter the fortress and destroy it," said Sitkovsky.
"However, if anti-tumour immune cells are not present, oxygen will have no impact," said Sitkovsky.
In the early 2000s, Sitkovsky found that a receptor on the surface of immune cells - the A2A adenosine receptor is responsible for preventing T cells from invading tumours and for "putting to sleep" those killer cells that do manage to enter into the tumours.
His latest work shows that supplemental oxygen weakened tumour-protecting signalling through the A2A adenosine receptor and wakes up the T cells that were able to invade lung tumours.
Sitkovsky noted that the effects of supplemental oxygenation might be even stronger in combination with a synthetic agent that he calls "super-caffeine," which is known to block the tumour-protecting effects of the adenosine receptor.
He and Graham Jones, professor and chair of Northeastern's Department of Chemistry and Chemical Biology, are collaborating to design the next generation of this drug, which was originally developed for patients with Parkinson's disease.
"The anti-tumour effects of supplemental oxygen can be further improved by the natural antagonist of the A2A adenosine receptor, which happens to be the caffeine in your coffee," Sitkovsky said.
The findings were published in the journal Science Translational Medicine.
