In Chapel Hill, North Carolina, a protein best known for sensing stray DNA is turning out to have another job: helping cells keep cholesterol in check. Researchers at the University of North Carolina Lineberger Comprehensive Cancer Center found that cGAS can influence how genes work inside the cell nucleus—and that role may affect how tumors grow and respond to treatment.
The finding, published Nov. 2, 2026, in the Journal of Clinical Investigation, adds a new piece to the puzzle of how cancer cells change their metabolism. cGAS normally acts as part of the body’s innate immune system, its built-in defense against germs. It detects harmful DNA in the cell’s cytoplasm, the space between the cell’s outer membrane and nucleus, and helps trigger an immune response. The UNC team found that cGAS also works in the nucleus, where it can help control which genes are active.
The researchers mapped where cGAS attaches across the genome and identified genes it helps regulate. They found that other proteins involved in cell growth and stress responses bring cGAS to particular regions of DNA. There, cGAS boosts production of LGALS3, a protein that helps regulate cholesterol and affects cell behavior.
This chain of events lowers the cell’s supply of acetyl-CoA, a molecule used to make cholesterol. When cGAS is absent, cells build up more cholesterol. That excess changes the makeup of cell membranes and switches on a growth-related signaling pathway, which can help cells grow larger, fuel tumors and make cancer harder to treat.
In laboratory studies and mouse tumor models, tumors without cGAS grew significantly faster and showed stronger activity in that pathway. Restoring cGAS slowed tumor growth and reduced cholesterol buildup. Restoring LGALS3 alone also had these effects, pointing to a possible role for the protein in the process.
The team also found that cancer cells lacking cGAS resisted chemotherapy drugs such as doxorubicin, as well as cholesterol-lowering medicines. Adding cGAS or LGALS3 back reversed that resistance in the tested cells. Senior author Pengda Liu, an associate professor of biochemistry and biophysics at UNC, said the results do not yet show whether this cholesterol-related effect applies broadly to all chemotherapy or targeted treatments. The team did find the signaling role in some immune-fighting white blood cells and normal epithelial cells, which line body surfaces and organs, as well as in cancer cells.
The work suggests that changing cGAS activity or targeting the LGALS3 pathway could one day help slow tumors or improve existing treatments. Those ideas still need testing; the study does not establish a treatment for patients. Liu and colleagues say they next want to learn how cGAS’s regulatory role changes as tumors develop and become resistant to treatment. Since cholesterol metabolism matters in many diseases, the findings may also prove useful beyond cancer.