Our bodies have the natural ability to target and kill infected or malignant cells, and people have long sought to use our own immune system to treat difficult diseases, such as cancer. Such treatments are known as “immunotherapy” and have become one of the most promising advances in the field of modern cancer treatment. Specifically, our immune system uses a type of white blood cell, cytotoxic CD8+ T cells, to “seek and destroy” cells that have been tagged as abnormal, such as cancerous cells. However, some cancer cells can avoid being tagged, and thus avoid being attacked by CD8+ T cells.
Recently, Snyder et al. have discovered a novel way to activate CD8+ T cells in order to target un-tagged cancer cells. First, they engineered tumor cells to produce a protein called RIPK3 that sends a signal to CD8+ T cells to destroy the engineered tumor cells themselves. This process is known as necroptosis, or “cellular suicide”. Next, the authors injected these engineered tumor cells into malignant tumors in mice. The cells produced RIPK3 in the tumor environment, thus activating CD8+ T cells to attack both the engineered cells as well as the surrounding tumor cells. The scientists tested this method in a mouse model, and they were able to significantly reduce tumor growth by about 70% and promote complete tumor clearance in 69.2% of mice.
These results are promising and point towards a possible new strategy for exploiting CD8+ T cells for cancer treatment. The authors also showed that this necroptotic pathway can be combined effectively with current immunotherapies to improve tumor elimination in mice, further highlighting the potential of this pathway to be used clinically in conjunction with other therapies. However, this study is mainly validated in mouse models, and more work needs to be done to show that this can be useful in patients.
Managing Correspondent: Wei Li
Original Article: Intratumoral activation of the necroptotic pathway components RIPK1 and RIPK3 potentiates antitumor immunity. Science immunology.
Media coverage: Injecting dying cells to trigger tumor destruction. Technology networks.
Could an injection of dead cells help fight cancer? Live Science.
Image Credit: Wikimedia Commons