Dataset Information

NPM1 promotes nasopharyngeal carcinoma metastasis and stemness by recruiting Mdm2 to induce the ubiquitination-mediated degradation of p53.

ABSTRACT: Nasopharyngeal carcinoma (NPC) is clinically challenging due to the development of distant metastasis following initial therapy. Therefore, it is necessary to elucidate the mechanisms underlying metastases to develop novel therapeutic strategies. Nucleophosmin 1 (NPM1) has been directly linked to the development of human tumors and may have both tumor-suppressing and oncogenic properties. Although NPM1 is often overexpressed in solid tumors of various histopathological origins, its specific function in mediating the development of NPC is still unknown. Here, we investigated the role of NPM1 in NPC and discovered that NPM1 was elevated in clinical NPC samples and served as a predictor of the worst prognosis in NPC patients. Furthermore, the upregulation of NPM1 promoted the migration and the cancer stemness of NPC both in vitro and in vivo. Mechanistic analyses revealed that the E3 ubiquitin ligase Mdm2 was recruited by NPM1 to induce the ubiquitination-mediated proteasomal degradation of p53. Ultimately, knockdown of NPM1 suppressed the stemness and EMT signals. In summation, this study demonstrated the role and the underlying molecular mechanism of NPM1 in NPC, providing the evidence for the clinical application of NPM1 as a therapeutic target for the treatment of patients with NPC.

SUBMITTER: Hu L

PROVIDER: S-EPMC10244087 | biostudies-literature | 2023

REPOSITORIES: biostudies-literature

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NPM1 promotes nasopharyngeal carcinoma metastasis and stemness by recruiting Mdm2 to induce the ubiquitination-mediated degradation of p53.

Hu Liya L Gong Pinggui P Zhou Ni N Wang Shuilian S He Cui C Zhou Yixuan Y Li Qiwen Q Zhao Xueman X Peng Hong H

American journal of cancer research 20230515 5

Nasopharyngeal carcinoma (NPC) is clinically challenging due to the development of distant metastasis following initial therapy. Therefore, it is necessary to elucidate the mechanisms underlying metastases to develop novel therapeutic strategies. Nucleophosmin 1 (NPM1) has been directly linked to the development of human tumors and may have both tumor-suppressing and oncogenic properties. Although NPM1 is often overexpressed in solid tumors of various histopathological origins, its specific func ...[more]

PMID: 37293161

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Project description:MDM2 is the principal antagonist of the tumor suppressor p53. p53 binds to its cognate DNA element within promoters and activates the transcription of adjacent genes. These target genes include MDM2. Upon induction by p53, the MDM2 protein binds and ubiquitinates p53, triggering its proteasomal degradation and providing negative feedback. This raises the question whether MDM2 can also remove p53 from its target promoters, and whether this also involves ubiquitination. In the present paper, we employ the MDM2-targeted small molecule Nutlin-3a (Nutlin) to disrupt the interaction of MDM2 and p53 in three different cancer cell lines: SJSA-1 (osteosarcoma), 93T449 (liposarcoma; both carrying amplified MDM2), and MCF7 (breast adenocarcinoma). Remarkably, removing Nutlin from the culture medium for less than five minutes not only triggered p53 ubiquitination, but also dissociated most p53 from its chromatin binding sites, as revealed by chromatin immunoprecipitation. This also resulted in reduced p53-responsive transcription, and it occurred much earlier than the degradation of p53 by the proteasome, arguing that MDM2 removes p53 from promoters prior to and thus independent of degradation. Accordingly, the short-term pharmacological inhibition of the proteasome did not alter the removal of p53 from promoters by Nutlin washout. However, when the proteasome inhibitor was applied for several hours, depleting non-conjugated ubiquitin prior to eliminating Nutlin, this compromised the removal of DNA-bound p53, as did an E1 ubiquitin ligase inhibitor. This suggests that the ubiquitination of p53 by MDM2 is necessary for its clearance from promoters. Depleting the MDM2 cofactor MDM4 in SJSA cells did not alter the velocity by that p53 was removed from promoters upon Nutlin washout. We conclude that MDM2 antagonizes p53 not only by covering its transactivation domain and by destabilization, but also by the rapid, ubiquitin-dependent termination of p53-chromatin interactions.

Dataset Information

NPM1 promotes nasopharyngeal carcinoma metastasis and stemness by recruiting Mdm2 to induce the ubiquitination-mediated degradation of p53.

Publications

NPM1 promotes nasopharyngeal carcinoma metastasis and stemness by recruiting Mdm2 to induce the ubiquitination-mediated degradation of p53.

Similar Datasets

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