SRC-3 coactivator regulates cell resistance to cytotoxic stress via TRAF4-mediated p53 destabilization

Genes Dev. 2013 Feb 1;27(3):274-87. doi: 10.1101/gad.203760.112.


Steroid receptor coactivator 3 (SRC-3) is an oncogenic nuclear receptor coactivator that plays a significant role in drug resistance. Using a lentiviral cDNA library rescue screening approach, we identified a SRC-3 downstream gene-TRAF4 (tumor necrosis factor [TNF] receptor associated-factor 4)-that functions in cell resistance to cytotoxic stress. TRAF4 expression is positively correlated with SRC-3 expression in human breast cancers. Similar to that observed for SRC-3 overexpression, breast cancer cells overexpressing TRAF4 are more resistant to stress-induced death. Here, we further dissected the underlying molecular mechanism for SRC-3 and TRAF4-mediated resistance to cytotoxic agents. We observed that SRC-3 expression is inversely correlated with the expression of p53-regulated proapoptotic genes in breast cancers and further found that SRC-3 and TRAF4 overexpression diminished cytotoxic stress-induced up-regulation of the tumor suppressor p53 protein. To determine the mechanism, we showed that the TRAF domain of TRAF4 bound to the N-terminal TRAF-like region of the deubiquitinase HAUSP (herpesvirus-associated ubiquitin-specific protease; also named USP7) and blocked the access of p53 to the same region of HAUSP. This TRAF4-mediated inhibition of HAUSP then led to the loss of p53 deubiquitination and its stabilization in response to cellular stress. Consistent with this cellular function, we also found that TRAF4 overexpression in breast cancer patients was associated significantly with poor prognosis. Because of SRC-3's ability to abrogate p53 function, our results suggest that SRC-3 overexpression may be especially important in tumors in which p53 is not mutated.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Breast Neoplasms / mortality
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Endopeptidases / metabolism
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Knockdown Techniques
  • HEK293 Cells
  • Humans
  • Mice
  • Nuclear Receptor Coactivator 3 / genetics
  • Nuclear Receptor Coactivator 3 / metabolism*
  • Protein Binding
  • Protein Stability
  • Stress, Physiological / physiology*
  • TNF Receptor-Associated Factor 4 / metabolism*
  • Tumor Suppressor Protein p53 / metabolism*
  • Ubiquitin-Specific Peptidase 7
  • Ubiquitin-Specific Proteases
  • Ubiquitination


  • Antineoplastic Agents
  • TNF Receptor-Associated Factor 4
  • Tumor Suppressor Protein p53
  • NCOA3 protein, human
  • Nuclear Receptor Coactivator 3
  • Endopeptidases
  • Ubiquitin-Specific Peptidase 7
  • Ubiquitin-Specific Proteases
  • Usp7 protein, mouse