Jianjun Wu, PhD

The human body’s immune system is a powerful weapon against cancer, but cancer can also create a complex environment that weakens immune system effectiveness. This environment, called the tumor microenvironment (TME), is made up of different cell types, including tumor cells and immune cells. Scientists have discovered a protein called STING that can change the TME and activate the immune system to fight cancer. However, STING therapy hasn’t worked well in clinical trials because tumors have become resistant to it. To activate STING, researchers use a small molecule called cGAMP. Treatment of cancer with cGAMP can activate STING in various cell types within the TME. When cGAMP is delivered to most immune cells in the TME, it activates STING and triggers an immune response against cancer. However, we found that cGAMP can also be delivered to T cells, which are important cells in killing cancer cells, it actually causes T cells to die. This weakens the immune system’s ability to fight cancer. Therefore, we think that the entry of cGAMP into T cells leads to their death, allowing tumor cells to escape being killed by T cells. Our goal is to identify the specific molecules responsible for cGAMP entry into T cells and develop new strategies to overcome tumor resistance to STING therapy by blocking the entry of cGAMP into T cells.