According to the American Cancer Society, ovarian cancer has become the fifth leading type of cancer death among women, with the majority of ovarian cancers classified as high-grade serous ovarian cancer (HGSOC)
This type of cancer is often deadly, and a key reason is that it can easily develop resistance to chemotherapy
Some scientists are considering using immunotherapy to overcome drug resistance
Immunotherapies typically target proteins associated with immune checkpoints, which release the "brakes" of the immune system and allow immune cells to start attacking cancer cells
But at present, the progress of immunotherapy in HGSOC is still slow, and finding the problem has become the premise of saving more HGSOC patients
According to new research in the Proceedings of the National Academy of Sciences (PNAS), for immunotherapy to really work, it is necessary to address the protective environment that cancer cells create for themselves
The study found that tumors make a signaling protein called focal adhesion kinase (FAK), which regulates the expression of the CD155 protein
It happens that CD155 itself can bind to the checkpoint receptor TIGIT on immune cells, and tumors indirectly control the activation state of immune cells through CD155
This is one way that tumors create a safe environment and evade detection by the immune system: The higher they raise CD155 levels, the less active the immune cells, and the safer they are
▲ Inhibiting FAK and reducing the level of CD155 are the prerequisites for improving the efficiency of immunotherapy (Image source: Reference , credit: UC San Diego Health Sciences)
In animal models, the researchers tried administering anti-FAK drugs to mice with ovarian cancer, and the mice started to drop levels of the protein CD155
At this time, after adding the TIGIT inhibitor, the combination of the two drugs can significantly improve the immune activity against ovarian cancer cells in mice
Compared with controls, mice given both drugs had significantly smaller tumors and better survival rates
Note: The original text has been deleted
 Tumor FAK orchestrates immunosuppression in ovarian cancer via the CD155/TIGIT axis, Proceedings of the National Academy of Sciences (2022).
 How ovarian cancer defies immunotherapy.
Retrieved Apr 12th, 2022 from https://medicalxpress.