Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster Display session 1

4808 - NORE1A induces a feedback termination of TNF signaling by antagonizing TNFR1 through ITCH-mediated destruction complex

Date

28 Sep 2019

Session

Poster Display session 1

Topics

Basic Science

Tumour Site

Presenters

Jieun Ahn

Citation

Annals of Oncology (2019) 30 (suppl_5): v1-v24. 10.1093/annonc/mdz238

Authors

J. Ahn, K. Ko, M. Lee, S. Chi

Author affiliations

  • College Of Life Science, KOREA UNIVSERSITY, 02841 - Seoul/KR

Resources

Login to get immediate access to this content.

If you do not have an ESMO account, please create one for free.

Abstract 4808

Background

NORE1A/RASSF5 is a tumor suppressor that is commonly inactivated in a variety of cancers. NORE1A is frequently down-regulated during tumor development and its inactivation often correlates with up-regulation of Ras activity. Although NORE1A was reported to be activated by NF-kB, its role in NF-kB signaling and the underlying mechanism have not been addressed. In this study, we explored the role for NORE1A in the regulation and function of the TNF-NF-kB pathway.

Methods

NORE1A effect on TNF regulation of inflammation, growth, and apoptosis was examined by flow cytometry, migration and invasion, and apoptosis assays. NORE1A regulation of TNF-NF-kB signaling was analyzed by quantitative RT-PCR, immunoblot, immunoprecipitation, and promoter luciferase assay.

Results

Upon exposure to TNF-a, NORE1A is induced by NF-kB signaling at the level of transcription while its activation suppresses TNF activation of NF-kB, indicating that NORE1A functions as a feedback terminator of TNF-NF-kB signaling. As predicted, NORE1A blocks TNF activation of pro-inflammatory gene transcription, epithelial-to-mesenchymal transition (EMT), invasion and migration. Mechanistically, NORE1A binds directly to TNF receptor I (TNFR1) and ubiquitin E3 ligase ITCH to promote ITCH-mediated K48-linked ubiquitination of TNFR1 and subsequent lysosomal degradation. Additionally, we identified that the PPXY motif of NORE1A interacts directly with ITCH using a series of deletion mutants. This interaction protects BAX from ITCH-mediated ubiquitination and thus activates its apoptotic function. NORE1A interaction with ITCH plays a crucial role for both TNFR1 degradation and BAX stabilization and activation.

Conclusions

In this study, we demonstrate first that NORE1A is a feedback terminator of TNF-NF-kB signaling, which directly antagonizes TNFR1 by facilitating the ITCH-TNFR1 interaction. Our study also shows that NORE1A binding to ITCH releases ITCH from BAX and activates BAX-mediated apoptosis. These data illuminate the mechanistic consequence of NORE1A inactivation in tumorigenesis.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Sung-gil, Chi.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.