oHSV-mediated JAG1 blockade induces glioma senescence-associated secretory phenotype to increase macrophage activation and sensitize to cetuximab-mediated senolysis

Oncolytic HSV-1 (oHSV) treatment induces Notch signaling and myelosuppression in the tumor microenvironment (TME) of preclinical models. In the clinic, upregulation of JAG1 gene expression was observed in recurrent high-grade glioma patients treated with CAN-3110. Since JAG1 is expressed on both glioma cells and tumor-associated macrophages (TAMs), and its expression correlated with a worse prognosis, we engineered a JAG1-antagonizing oHSV (OncoD-0J1) and interrogated its impact on the tumor and myeloid TME. OncoD-0J1 antagonized JAG1-mediated Notch signaling and had a significant therapeutic advantage in vivo, which relied on Notch signature in tumor cells. Kinome profiling revealed that OncoD-0J1 treatment suppressed CDK1, resulting in a G2/M cell cycle checkpoint as seen by cell cycle analysis. Cell cycle arrest led to senescence and correlated with increased reactive oxygen species, p62 accumulation, autophagosome accumulation, and senescence-associated beta-galactosidase activity. This resulted in increased production of inflammatory chemokines and DAMPs such as IL-1ß and extracellular ATP. RNA sequencing of murine macrophages co-cultured with infected human tumor cells showed enrichment of chemotactic and pro-inflammatory pathways as well as increased Fc receptor activation following OncoD-0J1 infection. Single-cell RNA sequencing and flow cytometric analysis of F4/80+ cells isolated from infected tumors showed a shift from tumor-supporting TAMs to inflammatory macrophages upon OncoD-0J1 treatment. Senescent cells showed heightened EGFR activation as a mechanism to escape death, which created a unique vulnerability for cetuximab as a senolytic agent. Combination therapy reduced EGFR signaling and induced macrophage-mediated antibody-dependent cellular cytotoxicity, thereby increasing the anti-tumor therapeutic response of OncoD-0J1 as a monotherapy. Overall design: Primary GBM cells were infected with OncoD or OncoD-0J1 at a multiplicity of infection (MOI) of 0.02 (GBM12) and 0.05 (GBM28) for 1 hour and media was changed to 0.05% FBS DMEM (n=4). Infected tumor cells were overlaid with serum-starved murine RAW 264.7 cells at a 1:1 ratio. 6 hours after co-culture, total RNA was isolated using the Rneasy Plus kit from Qiagen, and samples were submitted for bulk RNA sequencing.