Proteomics identifies neddylation as a potential therapy target in small intestinal neuroendocrine tumors

Oncogene. 2019 Oct;38(43):6881-6897. doi: 10.1038/s41388-019-0938-8. Epub 2019 Aug 12.


Patients with small intestinal neuroendocrine tumors (SI-NETs) frequently develop spread disease; however, the underlying molecular mechanisms of disease progression are not known and effective preventive treatment strategies are lacking. Here, protein expression profiling was performed by HiRIEF-LC-MS in 14 primary SI-NETs from patients with and without liver metastases detected at the time of surgery and initial treatment. Among differentially expressed proteins, overexpression of the ubiquitin-like protein NEDD8 was identified in samples from patients with liver metastasis. Further, NEDD8 correlation analysis indicated co-expression with RBX1, a key component in cullin-RING ubiquitin ligases (CRLs). In vitro inhibition of neddylation with the therapeutic agent pevonedistat (MLN4924) resulted in a dramatic decrease of proliferation in SI-NET cell lines. Subsequent mass spectrometry-based proteomics analysis of pevonedistat effects and effects of the proteasome inhibitor bortezomib revealed stabilization of multiple targets of CRLs including p27, an established tumor suppressor in SI-NET. Silencing of NEDD8 and RBX1 using siRNA resulted in a stabilization of p27, suggesting that the cellular levels of NEDD8 and RBX1 affect CRL activity. Inhibition of CRL activity, by either NEDD8/RBX1 silencing or pevonedistat treatment of cells resulted in induction of apoptosis that could be partially rescued by siRNA-based silencing of p27. Differential expression of both p27 and NEDD8 was confirmed in a second cohort of SI-NET using immunohistochemistry. Collectively, these findings suggest a role for CRLs and the ubiquitin proteasome system in suppression of p27 in SI-NET, and inhibition of neddylation as a putative therapeutic strategy in SI-NET.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Apoptosis / drug effects
  • Carrier Proteins / metabolism
  • Cell Line, Tumor
  • Cyclopentanes / pharmacology
  • Cyclopentanes / therapeutic use
  • Female
  • Humans
  • Intestinal Neoplasms / drug therapy*
  • Intestinal Neoplasms / metabolism*
  • Intestine, Small / drug effects*
  • Intestine, Small / metabolism*
  • Male
  • Middle Aged
  • NEDD8 Protein / metabolism
  • Neuroendocrine Tumors / drug therapy*
  • Neuroendocrine Tumors / metabolism*
  • Proliferating Cell Nuclear Antigen / metabolism
  • Proteomics / methods
  • Pyrimidines / pharmacology
  • Pyrimidines / therapeutic use
  • RNA, Small Interfering / metabolism
  • Ubiquitins / metabolism


  • Carrier Proteins
  • Cyclopentanes
  • NEDD8 Protein
  • Proliferating Cell Nuclear Antigen
  • Pyrimidines
  • RNA, Small Interfering
  • Ubiquitins
  • p27 antigen
  • pevonedistat