Abstract LB280: Enhancing glioblastoma radiotherapy by COMT inhibition

Abstract There is an urgent unmet medical need to discover novel therapeutics to enhance the efficacy of glioma radiotherapy. Here we assessed the roles of catechol - o - methyltransferase COMT, a key enzyme in dopamine metabolism and a drug target for Parkinson's disease, in glioma treatment. Analysis of TCGA data showed significantly higher COMT expression levels in glioma versus normal brain tissues. Inhibition of COMT by genetic knockout or FDA - approved COMT inhibitors significantly sensitized glioma cells to radiotherapy in vitro and murine glioma in vivo. Mechanistically, COMT inhibition in glioblastoma cells led to mitochondria dysfunction and increased mitochondrial RNA release into the cytoplasm, activating the cellular antiviral dsRNA sensing pathway and type I IFN response. Elevated type I IFNs stimulated microglial cells′ phagocytic capacity, enhancing radiotherapy efficacy. Because of the long - established safety record of the COMT inhibitors, our findings provide a solid rationale to evaluate them in combination with radiotherapy in glioma patients. Citation Format: Meng Jiao, Christopher J. Pirozzi, Chen Yu, Xuhui Bao, Mengjie Hu, Dong Pan, Sejiro Littleton, Nathan Reynolds, Daniel R. Saban, Fang Li, Chuan-yuan Li. Enhancing glioblastoma radiotherapy by COMT inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB280.