Funded by us, researchers have discovered a new type of immunotherapy that could stop breast cancer from growing and spreading. They found that targeting a protein called endosialin using a specific type of immunotherapy disrupts the tumour's blood supply. This can hinder its growth and spread. The researchers are developing this treatment further so that it can be tested in clinical trials.
Immunotherapy and breast cancer
Immunotherapy is a type of cancer treatment that helps the body’s immune system recognise and kill cancer cells.
Professor Clare Isacke and Dr Frances Turrell, from our research centre at The Institute of Cancer Research (ICR), London, studied a type of immunotherapy called CAR-T therapy. CAR-T therapy is a treatment that involves taking a sample of healthy immune cells from a person and then modifying them so they can attack specific targets.
CAR-T therapies are already being used to treat some blood cancers. And scientists are trying to find ways to make them effective for other types of cancer, including breast cancer.
Targeting cancer-supporting cells
CAR-T therapy doesn’t always work on breast tumours because cells around the tumour suppress the immune response. And it can be hard to find specific features on the breast cancer cells to target.
So, Clare and her team directed the CAR T-cells to a protein called endosialin. Endosialin is found in large amounts in cells that surround the blood vessels of solid tumours.
Instead of targeting the cancer cells directly, this treatment focuses on the cells that play a crucial role in supporting the disease.
Testing this new approach
The researchers tested this approach in mice and found that targeting endosialin reduced the breast cancer’s growth and spread successfully.
The team then tested the treatment on lung cancer tumours in mice and saw similarly successful results. This suggests that people with other types of cancer might benefit from this new treatment too.
In addition, they found that the CAR-T therapy didn’t affect cells without endosialin. This indicates that the new treatment could be cancer-specific, with potentially fewer side effects.
This is the very first study that demonstrates the effectiveness of using endosialin-directed CAR-T cells to reduce breast cancer tumour growth and spread. Immunotherapy has had limited success in treating breast cancer but by targeting the cells that support the tumour and help it to survive, rather than the cancer cells directly, we’ve found a promising way to overcome the challenges posed by the tumour environment and develop a more effective and targeted treatment for breast cancer.
Dr Frances Turrell
Study co-leader and postdoctoral training fellow, Division of Breast Cancer Research at the ICR
Looking ahead
The researchers are now developing this treatment further, so it can be tested in clinical trials. They hope that this discovery could lead to better treatments for people with breast cancer in the future.
This exciting research could lead to much-needed targeted treatments for people with breast cancer, and with 1 person dying from breast cancer every 45 minutes in the UK, new treatments like these are urgently needed. Now we know that the treatment works in principle in mice, Breast Cancer Now researchers can continue to develop this immunotherapy to make it suitable for people, as well as to understand the full effect it could have and who it may benefit the most.
Dr Simon Vincent
Director of research, support and influencing at Breast Cancer Now
This study was published in the Journal for ImmunoTherapy and funded by Breast Cancer Now and Cancer Research UK.