Some More Good News
Dr Coffelt and his team at the Beatson Institute for Cancer Research in Glasgow in another project funded by Secondary1st’s fundraisers and donors are working to understand why existing immunotherapies are less effective in treating breast cancer than other cancer types. They recently published a report on a significant discovery that breast cancer immunotherapy could be more effective if an immune cell that prevents it from working is targeted at the same time. This discovery, published in the Journal of Experimental Medicine, may be the first step in uncovering new ways to stop the disease spreading to the lung. When breast cancer spreads to other parts of the body it’s known as secondary (metastatic) breast cancer which can’t be cured. Researchers at the University of Glasgow, led by Dr Seth Coffelt, built on previous findings to understand how an immune cell called a gamma delta T cell can weaken the impact of immunotherapy.
Immunotherapy is a cancer treatment which turns on the immune system to fight the disease. It works by helping the immune system recognise and attack cancer cells. The team found that removing gamma delta T cells stopped breast cancer spreading to the lung in mice treated with a type of immunotherapy called checkpoint inhibitors. They also uncovered a sequence of events that reduced the effectiveness of this immunotherapy treatment and a potential way to counteract it. Breast cancer cells can trick nearby immune cells to release molecules which trigger gamma delta T cells to multiply and make their own molecule called IL-17A. This molecule is already known to benefit cancer cells and can make the immunotherapy less effective.
When mice with and without gamma delta T cells were treated with immunotherapy, the drugs successfully prevented breast cancer from spreading to the lung in those where the cells were absent.
This suggests that targeting gamma delta T cells and the molecule IL-17A has the potential to help immunotherapy drugs like pembrolizumab (Keytruda) be more effective at stopping secondary (metastatic) breast cancer in some patients.
