Regulation of Rad17 protein turnover unveils an impact of Rad17-APC cascade in breast carcinogenesis and treatment

J Biol Chem. 2013 Jun 21;288(25):18134-45. doi: 10.1074/jbc.M113.456962. Epub 2013 May 1.

Abstract

Aberrant regulation of DNA damage checkpoint function leads to genome instability that in turn can predispose cellular tissues to become cancerous. Previous works from us and others demonstrated the role of Rad17 in either activation or termination of DNA damage checkpoint function. In the current study, we have revealed the unexpected accumulation of Rad17 in various types of breast cancer cell lines as well as human breast cancer tissues. We observed that Rad17 protein turnover rate in breast epithelial cells is much faster than in breast cancer cells, where the turnover of Rad17 is regulated by the Cdh1/APC pathway. We further observed that Rad17-mediated checkpoint function is modulated by proteolysis. Stabilization of Rad17 disrupts cellular response to chemotherapeutic drug-induced DNA damage and enhances cellular transformation. In addition, manipulation of Rad17 by RNA interference or stabilization of Rad17 significantly sensitize breast cancer cell to various chemotherapeutic drugs. Our present results indicate the manipulation of Rad17 proteolysis could be a valuable approach to sensitize breast cancer cell to the chemotherapeutic treatment despite of the critical role in governing DNA damage response and cellular recovery from genotoxic stress.

Keywords: APC; Carcinogenesis; Chromosomes/non-histone Chromosomal Proteins; DNA Binding Protein; Genome Instability; Protein Dynamics; Protein Stability; Protein Turnover; Rad17.

Publication types

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

MeSH terms

  • Anaphase-Promoting Complex-Cyclosome
  • Antigens, CD
  • Antineoplastic Agents / pharmacology
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / genetics
  • Breast Neoplasms / pathology
  • Cadherins / genetics
  • Cadherins / metabolism*
  • Cell Cycle Checkpoints / drug effects
  • Cell Cycle Checkpoints / genetics
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Cisplatin / pharmacology
  • DNA Damage
  • Female
  • HEK293 Cells
  • Humans
  • Immunoblotting
  • MCF-7 Cells
  • Models, Genetic
  • Protein Binding / drug effects
  • Proteolysis / drug effects
  • RNA Interference
  • Signal Transduction*
  • Ubiquitin-Protein Ligase Complexes / genetics
  • Ubiquitin-Protein Ligase Complexes / metabolism*

Substances

  • Antigens, CD
  • Antineoplastic Agents
  • CDH1 protein, human
  • Cadherins
  • Cell Cycle Proteins
  • Rad17 protein, human
  • Ubiquitin-Protein Ligase Complexes
  • Anaphase-Promoting Complex-Cyclosome
  • Cisplatin