The role of nibrin in doxorubicin-induced apoptosis and cell senescence in Nijmegen Breakage Syndrome patients lymphocytes

PLoS One. 2014 Aug 13;9(8):e104964. doi: 10.1371/journal.pone.0104964. eCollection 2014.

Abstract

Nibrin plays an important role in the DNA damage response (DDR) and DNA repair. DDR is a crucial signaling pathway in apoptosis and senescence. To verify whether truncated nibrin (p70), causing Nijmegen Breakage Syndrome (NBS), is involved in DDR and cell fate upon DNA damage, we used two (S4 and S3R) spontaneously immortalized T cell lines from NBS patients, with the founding mutation and a control cell line (L5). S4 and S3R cells have the same level of p70 nibrin, however p70 from S4 cells was able to form more complexes with ATM and BRCA1. Doxorubicin-induced DDR followed by cell senescence could only be observed in L5 and S4 cells, but not in the S3R ones. Furthermore the S3R cells only underwent cell death, but not senescence after doxorubicin treatment. In contrary to doxorubicin treatment, cells from all three cell lines were able to activate the DDR pathway after being exposed to γ-radiation. Downregulation of nibrin in normal human vascular smooth muscle cells (VSMCs) did not prevent the activation of DDR and induction of senescence. Our results indicate that a substantially reduced level of nibrin or its truncated p70 form is sufficient to induce DNA-damage dependent senescence in VSMCs and S4 cells, respectively. In doxorubicin-treated S3R cells DDR activation was severely impaired, thus preventing the induction of senescence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibiotics, Antineoplastic / pharmacology*
  • Apoptosis / drug effects*
  • Ataxia Telangiectasia Mutated Proteins / metabolism
  • BRCA1 Protein / metabolism
  • Cell Cycle Checkpoints / drug effects
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line
  • Cellular Senescence / drug effects*
  • DNA Repair / drug effects
  • Down-Regulation
  • Doxorubicin / pharmacology*
  • Humans
  • Mutation
  • Myocytes, Smooth Muscle / cytology
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / metabolism
  • Nijmegen Breakage Syndrome / drug therapy*
  • Nijmegen Breakage Syndrome / genetics
  • Nijmegen Breakage Syndrome / metabolism
  • Nijmegen Breakage Syndrome / pathology
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • T-Lymphocytes / drug effects*
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / pathology

Substances

  • Antibiotics, Antineoplastic
  • BRCA1 Protein
  • Cell Cycle Proteins
  • NBN protein, human
  • Nuclear Proteins
  • Doxorubicin
  • Ataxia Telangiectasia Mutated Proteins

Grant support

This work was supported by National Center of Science in Poland (grants: 2011/01/M/NZ1/01597, UMO-2011/01/B/NZ3/02137 and 0728/B/P01/2011/40). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.