Regulation of eIF2α by RNF4 Promotes Melanoma Tumorigenesis and Therapy Resistance

Emily Avitan-Hersh, Yongmei Feng, Avital Oknin Vaisman, Yamen Abu Ahmad, Yaniv Zohar, Tongwu Zhang, Joo Sang Lee, Ikrame Lazar, Saeed Sheikh Khalil, Yulia Feiler, Harriet Kluger, Chaim Kahana, Kevin Brown, Eytan Ruppin, Ze'ev A. Ronai, Amir Orian

Research output: Contribution to journalArticlepeer-review

Abstract

Among the hallmarks of melanoma are impaired proteostasis and rapid development of resistance to targeted therapy that represent a major clinical challenge. However, the molecular machinery that links these processes is unknown. Here we describe that by stabilizing key melanoma oncoproteins, the ubiquitin ligase RNF4 promotes tumorigenesis and confers resistance to targeted therapy in melanoma cells, xenograft mouse models, and patient samples. In patients, RNF4 protein and mRNA levels correlate with poor prognosis and with resistance to MAPK inhibitors. Remarkably, RNF4 tumorigenic properties, including therapy resistance, require the translation initiation factor initiation elongation factor alpha (eIF2α). RNF4 binds, ubiquitinates, and stabilizes the phosphorylated eIF2α (p-eIF2α) but not activating transcription factor 4 or C/EBP homologous protein that mediates the eIF2α−dependent integrated stress response. In accordance, p-eIF2α levels were significantly elevated in high-RNF4 patient-derived melanomas. Thus, RNF4 and p-eIF2α establish a positive feed-forward loop connecting oncogenic translation and ubiquitin-dependent protein stabilization in melanoma.

Original languageEnglish
Pages (from-to)2466-2477
Number of pages12
JournalJournal of Investigative Dermatology
Volume140
Issue number12
DOIs
StatePublished - Dec 2020
Externally publishedYes

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