Oxygen can help strengthen our own immune cells and awaken their abilities to fight off cancerous tumour cells, scientists in America have reported.
With new statistics suggesting one in two people will be diagnosed with cancer in their lifetime, the search for new forms of treatment is as important as ever.
Research into cancer immunotherapies has brought promising results. Based on the idea of using our bodies’ natural immune defences to fight off tumours, treatments involve increasing the number, or boosting the cancer tackling abilities, of immune cells.
Cancerous tumours have their own strategies, however, to combat the natural defences of our bodies. Tumours grow very quickly and blood supply to them is often not robust and reliable, creating a hypoxic micro-environment (one that is very low in oxygen) within the tumour.
In low oxygen conditions cancer cells produce a chemical called adenosine which can bind to receptors on a group of immune cells called T cells - and effectively puts them to sleep. This stops them from doing their job of killing the tumour cells.
Writing in Science Translational Medicine a team lead by Dr Michail Sitkovsky, from the New England Inflammation and Tissue Protection Institute have discovered increasing oxygen intake can reverse hypoxia, reducing the amount of adenosine and awakening the T cells. Active T cells can soldier on and reduce the size of cancerous tumours.
“We have simply combated the hypoxia by increasing the amount of oxygen being delivered to the tumours” explains author Dr Stephen Hatfield. Using 60% oxygen, rather than the 21% that is in the normal air we breathe, Hatfield was able to reduce the size of tumours and improve survival in mice with lung cancer.
Increasing oxygen availability could also greatly improve the effect of other cancer treatments. Cancer vaccines work by increasing the number of immune cells available to fight the tumour; however without the reversal of the low oxygen environment of the tumour the extra immune cells may be ineffective, as they will be inhibited by adenosine.
Clinical trials are currently being set up and Hatfield is optimistic about the results due to the safe and inexpensive nature of using supplimental oxygen.
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