J Clin Invest. 2026 Feb 16. pii: e198843. [Epub ahead of print]136(4):
Shashwat Tripathi,
Hinda Najem,
Lisa Hurley,
Ruochen Du,
Crismita Dmello,
Heba Ali,
Kathleen McCortney,
Karl J Habashy,
Peng Zhang,
Craig M Horbinski,
Lara Leoni,
Ryan J Avery,
Rimas V Lukas,
Timothy L Sita,
David R Raleigh,
Sean Sachdev,
Roger Stupp,
Maciej S Lesniak,
David M Ashley,
Daniele Procissi,
Michael A Curran,
Irina Balyasnikova,
Amy B Heimberger.
Radiation therapy (RT) is the standard of care for glioblastoma but is not curative. Triggering the cGAS/stimulator of interferon genes (STING) pathway with potent agonists, such as 8803, exerts activity across high-grade glioma preclinical models. To determine if the combination of 8803 with RT warrants consideration in the up-front treatment setting and to clarify the underlying mechanisms of therapeutic activity, C57BL/6J mice harboring intracerebral CT-2A or QPP8v gliomas were treated with RT, intratumoral 8803, or both. The treatment with the combination resulted in 80% long-term survival in the CT-2A model but not in the radiation-resistant QPP8v model. This therapeutic effect was maintained in Sting-/- CT-2A cells, highlighting the direct role of the immune system in mediating the survival benefit. Single-cell RNA-Seq identified increased nitric oxide synthase 2 (Nos2) in inflammatory tumor-associated macrophages; however, the therapeutic effect was maintained in Nos2-/- mice. Additionally, 8803 reprogrammed the blood-brain barrier (BBB) by altering the Pecam and Cd147 pathways in endothelial cells; intracranial injection of 8803 induced bihemispheric BBB opening for up to 24 hours. Sting activation was visualized longitudinally using 3'-deoxy-3'-[18F]-fluorothymidine ([18F]-FLT) PET, which peaked 72-96 hours after 8803 administration. In summary, 8803 combined with RT triggers distinctive antiglioma immune reactivity, facilitates BBB opening, and warrants consideration for up-front clinical trials in glioblastoma, where treatment effects can be monitored using [18F]-FLT PET imaging.
Keywords: Brain cancer; Cancer immunotherapy; Immunology; Oncology; Therapeutics; Vascular biology