CHK1 and RAD51 activation after DNA damage is regulated via urokinase receptor/TLR4 signaling

Cell Death Dis. 2016 Sep 29;7(9):e2383. doi: 10.1038/cddis.2016.291.

Abstract

Mechanisms of DNA damage and repair signaling are not completely understood that hinder the efficiency of cancer therapy. Urokinase-type plasminogen activator receptor (PLAUR) is highly expressed in most solid cancers and serves as a marker of poor prognosis. We show that PLAUR actively promotes DNA repair in cancer cells. On the contrary, downregulation of PLAUR expression results in delayed DNA repair. We found PLAUR to be essential for activation of Checkpoint kinase 1 (CHK1); maintenance of cell cycle arrest after DNA damage in a TP53-dependent manner; expression, nuclear import and recruitment to DNA-damage foci of RAD51 recombinase, the principal protein involved in the homologous recombination repair pathway. Underlying mechanism implies auto-/paracrine signaling of PLAUR/TLR4 receptor complex leading to activation of CHK1 and DNA repair. The signaling is induced by a danger molecule released by DNA-damaged cells and mediates, at least partially, activation of DNA-damage response. This study describes a new mechanism of DNA repair activation initiated by auto-/paracrine signaling of membrane receptors PLAUR/TLR4. It adds to the understanding of role of PLAUR in cancer and provides a rationale for therapeutic targeting of PLAUR/TLR4 interaction in TP53-positive cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Checkpoints
  • Cell Nucleus / metabolism
  • Checkpoint Kinase 1 / metabolism*
  • DNA Damage*
  • DNA Repair
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Models, Biological
  • Phosphorylation
  • Protein Transport
  • RNA, Small Interfering / metabolism
  • Rad51 Recombinase / metabolism*
  • Receptors, Urokinase Plasminogen Activator / metabolism*
  • Signal Transduction*
  • Toll-Like Receptor 4 / metabolism*
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • RNA, Small Interfering
  • Receptors, Urokinase Plasminogen Activator
  • Toll-Like Receptor 4
  • Tumor Suppressor Protein p53
  • Checkpoint Kinase 1
  • Rad51 Recombinase