USP21-mediated NLRP3 deubiquitination enhances radiosensitivity in nasopharyngeal carcinoma by inducing pyroptosis

SHI Xin; CHEN Jinwei; JIANG Yuan

doi:10.3969/j.issn.1002-7386.2025.06.004

Abstract：Objective To explore the influence of ubiquitin-specific protease 21(USP21)-mediated nucleotide-binding domain(NOD)-like receptor(NLR)family member pyrin domain-containing protein 3(NLRP3)deubiquitination on nasopharyngeal carcinoma(NPC)radiosensitivity and its potential mechanism.Methods Pyroptosis was assessed by phase-contrast imaging.The regulatory effects of USP21 and NLRP3 on the proliferation of NPC cells were assessed by colony formation assay.Quantitative reverse-transcription polymerase chain reaction(qRT-PCR)was used to measure the mRNA expression NLRP3.Western blot was performed to analyze protein expressions.Coimmunoprecipitation assay was used to evaluate deubiquitination.A xenograft model was created to investigate the effect of NLRP3 on pyroptosis and radiosensitivity of NPC in vivo.Results Irradiation(IR)induced pyroptosis of NPC cells,and the expressions of NLRP3,ASC,Cl-caspase-1,IL-1β,IL-18,cl-caspase-3,cl-PARP and Cyto C were significantly upregulated(P＜0.05).knockdown of NLRP3 relieved IR-induced morphological changes in pyroptosis of NPC cells.Overexpression of NLRP3 promoted the generation of more pyrogens and inhibited colony formation.In vivo experiments showed that NLRP3 overexpression had no significant effect on tumor fluorescence signal intensity,tumor size,and tumor volume without IR irradiation(P＞0.05).However,overexpression of NLRP3 in IR-induced xenografts significantly inhibited the tumor fluorescence signal,growth rate,and tumor volume,but upregulated ASC,Cl-caspase-1,IL-1β and IL-18 in the tumor tissue(P＜0.05).Overexpression of USP21 significantly upregulated NLRP3 and decreased NLRP3 ubiquitination,while USP21 knockdown downregulated NLRP3 and reduced NLRP3 ubiquitination(P＜0.05).Knockdown of NLRP3 reduced the increase in pyrogens and reduction of colony formation induced by USP21 overexpression(P＜0.05).Conclusion USP21-mediated NLRP3 deubiquitination enhances radiosensitivity in NPC by inducing pyroptosis.