20.500.12556/DiRROS-25288 Human papillomavirus-related oropharyngeal squamous cell carcinoma exhibits enhanced radiosensitivity despite limited activation of cytosolic DNA sensing pathways and innate immune responses Pharyngeal squamous cell carcinoma (PSCC) is a significant health concern, with human papillomavirus 16 (HPV16) playing a key role in the etiology of oropharyngeal squamous cell carcinoma (OPSCC). HPV16-related OPSCC exhibits enhanced radiosensitivity compared to HPV16-unrelated PSCC, yet the underlying mechanisms remain poorly understood. As HPV16 oncoproteins E6 and E7 are known to interfere with innate immune signaling, we investigated how modulation of cytosolic DNA sensing pathways and innate immune responses changes after irradiation (IR) and whether this contributes to enhanced radiosensitivity in HPV16-related OPSCC. Materials and methods Using HPV16-related and -unrelated PSCC models, we examined baseline expression levels of DNA sensors and cytokines and assessed the effects of IR on double-stranded DNA (dsDNA) accumulation, activation of cytosolic DNA sensors, cytokines, and immune cell infiltration both in vitro and in vivo. Analyses were performed using real-time quantitative polymerase chain reaction (RT-qPCR) and immunofluorescent staining. Results HPV16-related OPSCC exhibited a distinct baseline expression profile of DNA sensors and cytokines, consistent with suppression of the stimulator of interferon genes (STING) pathway. While IR-induced activation of DNA sensors was dose- and time-dependent across models, HPV16-related OPSCC showed selective activation of cyclic GMP-AMP synthase (cGAS) and STING without significant cytokine upregulation or immune activation. In contrast, HPV16-related and unrelated PSCCs displayed activation of multiple DNA sensors, increased cytokine expression, and enhanced immune cell infiltration following IR. Conclusions The key finding was that the involvement of cytosolic DNA sensing pathways and innate immune system do not increase radiosensitivity of HPV16-related OPSCC. In PSCC models, DNA sensor and cytokine expression varied depending on IR dose and fractionation. human papillomavirus oropharyngeal squamous cell carcinoma radiosensitivity humani papilomavirus ploščatocelični rak grla radiosenzitivnost true false true Association of Radiology and Oncology Ljubljana Angleški jezik Slovenski jezik by Authors Neznano 2026-01-15 03:48:21 2026-01-16 14:50:21 2026-01-17 04:06:03 0000-00-00 00:00:00 2025 0 Ljubljana 0 str. 566-578 no. 4 Vol. 59 Dec. 2025 0000-00-00 Zaloznikova Objavljeno apc 2025-08-27 2025-09-05 2025-12-01 616-006 1318-2099 10.2478/raon-2025-0057 262920963 RAZ_Levpuscek_Kristina_2025.pdf RAZ_Levpuscek_Kristina_2025.pdf 1 A7FDDD0865322CAC7A86EB4DD924AA73 75fdebe8db6216e6e8b3b3e0d352ede417f32128dffd167f98cbaac93d51b074 8c5dd6de-f2e2-11f0-a15d-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=38364 Onkološki inštitut Ljubljana 0 0 0