MIT researchers developed a new cancer immunotherapy that makes tumors help destroy themselves. They used lipid nanoparticles (LNPs) to deliver mRNA encoding the enzyme cGAS into cancer cells. This enzyme triggers production of cGAMP, a natural molecule that activates the STING pathway in nearby immune cells, stimulating a powerful antitumor immune response.
In mouse models of melanoma, the treatment slowed tumor growth on its own and worked even better when combined with immune checkpoint blockade (anti–PD-1), completely eradicating tumors in 30% of mice. The approach mimics natural immune signaling, reducing the toxicity and side effects seen with direct delivery of synthetic STING agonists, which often require high doses that cause inflammation and tissue damage.
By making cancer cells generate and release their own immune activators, the method turns the tumor microenvironment into a localized immune-stimulating system. This allows strong immune activation with minimal systemic effects. The researchers now aim to adapt the therapy for systemic delivery and test combinations with chemotherapy or radiotherapy, which increase DNA damage and could further enhance cGAMP production.
In summary, the study shows that reprogramming cancer cells to produce their own immune-stimulating molecules can transform them from immune evaders into immune activators, offering a promising and safer path toward more effective cancer immunotherapies.
Credit: GEN