Abstract 1113: USP18 impairs the sensitivity of radiotherapy for nasopharyngeal carcinoma by promoting the ubiquitination and nuclear translocation of TRIM29

Abstract

Abstract Radiotherapy is the main and preferred treatment for nasopharyngeal carcinoma (NPC), owing to its high sensitivity to radiation. However, there are ~20% patients suffering from tumor recurrence. Accumulating evidences show that protein ubiquitination plays a vital role in radiation caused DNA damage response. Here, we identified that the deubiquitinase USP18 is highly expressed in NPC tissues, and inversely associated with radiosensitivity of NPC cells. USP18 interacts with TRIM29 and promotes its K27-linked ubiquitination independent of its deubiquitinase activity. Further investigation reveals that USP18 acts as a scaffold to recruit the E3 ubiquitin ligase TRIM21 to directly ubiquitinate TRIM29 at Lys307, thus promoting its oligomerization and nuclear translocation, and thereby facilitates the DNA damage repair of NPC cells after irradiation. Clinically, higher expression of USP18 indicates poor response to radiotherapy and worse prognosis in NPC patients. Our findings reveal the critical role of USP18 in regulating radiosensitivity, and targeting USP18-TRIM21-TRIM29 axis maybe a novel strategy to synergize with radiotherapy for NPC patients. Citation Format: Jia-Yi Lin, Wei-Wei Zhang, Qing-Jie Li, Xue-Liang Fang, Jun-Yan Li, Shi-Wei He, Ying-Qin Li, Jun Ma, Na Liu, Yin Zhao, Rui Guo. USP18 impairs the sensitivity of radiotherapy for nasopharyngeal carcinoma by promoting the ubiquitination and nuclear translocation of TRIM29 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1113.