ZRANB1 Is an EZH2 Deubiquitinase and a Potential Therapeutic Target in Breast Cancer

Cell Rep. 2018 Apr 17;23(3):823-837. doi: 10.1016/j.celrep.2018.03.078.

Abstract

Although EZH2 enzymatic inhibitors have shown antitumor effects in EZH2-mutated lymphoma and ARID1A-mutated ovarian cancer, many cancers do not respond because EZH2 can promote cancer independently of its histone methyltransferase activity. Here we identify ZRANB1 as the EZH2 deubiquitinase. ZRANB1 binds, deubiquitinates, and stabilizes EZH2. Depletion of ZRANB1 in breast cancer cells results in EZH2 destabilization and growth inhibition. Systemic delivery of ZRANB1 small interfering RNA (siRNA) leads to marked antitumor and antimetastatic effects in preclinical models of triple-negative breast cancer (TNBC). Intriguingly, a small-molecule inhibitor of ZRANB1 destabilizes EZH2 and inhibits the viability of TNBC cells. In patients with breast cancer, ZRANB1 levels correlate with EZH2 levels and poor survival. These findings suggest the therapeutic potential for targeting the EZH2 deubiquitinase ZRANB1.

Keywords: EZH2; ZRANB1; breast cancer; deubiquitinase.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Enhancer of Zeste Homolog 2 Protein / antagonists & inhibitors
  • Enhancer of Zeste Homolog 2 Protein / genetics
  • Enhancer of Zeste Homolog 2 Protein / metabolism
  • Female
  • HEK293 Cells
  • Humans
  • Kaplan-Meier Estimate
  • Mice
  • Mice, Inbred C57BL
  • Protein Binding
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • RNA, Small Interfering / therapeutic use
  • Transplantation, Heterologous
  • Triple Negative Breast Neoplasms / drug therapy
  • Triple Negative Breast Neoplasms / mortality
  • Triple Negative Breast Neoplasms / pathology*
  • Ubiquitin-Specific Proteases / antagonists & inhibitors
  • Ubiquitin-Specific Proteases / genetics
  • Ubiquitin-Specific Proteases / metabolism*
  • Zinc Fingers

Substances

  • RNA, Small Interfering
  • EZH2 protein, human
  • Enhancer of Zeste Homolog 2 Protein
  • Ubiquitin-Specific Proteases