Insulin-like growth factor I receptor is expressed at normal levels in Nijmegen breakage syndrome cells

Hiroshi Watanabe, Dong Yu, Takehito Sasaki, Hitoshi Shibuya, Yoshio Hosoi, Minoru Asada, Kenshi Komatsu, Masahiko Miura

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Nijmegen breakage syndrome (NBS) is an autosomal recessive disorder sharing a pleiotropic phenotype with ataxia-telangiectasia (A-T), including increased radiosensitivity and cancer disposition. Insulin-like growth factor I receptor (IGF-IR) expression is reportedly decreased in A-T cells, which is thought to contribute to its increased radiosensitivity. In this study, we investigated whether the same mechanism underlies the radiosensitivity of NBS cells. GM7166VA7 cells lacking NBS1 protein displayed a phenotype of increased radiosensitivity, while the introduction of NBS1 cDNA conferred radioresistance comparable to normal cells. IGF-IR expression levels were essentially the same among normal, NBS, and NBS1-complemented NBS cells. There was no significant difference between NBS and NBS1-complemented cells in activation of major downstream pathways of IGF-IR upon IGF-I stimulation, including phosphatidylinositol-3′ kinase (PI3-K) and mitogen-activated protein kinase (MAPK). Collectively, IGF-IR-related events are unlikely to be disrupted in NBS cells, and therefore, defects in IGF-IR signaling do not explain the increased radiosensitivity of NBS cells.

Original languageEnglish
Pages (from-to)62-66
Number of pages5
JournalBiochemical and biophysical research communications
Issue number1
Publication statusPublished - 2002
Externally publishedYes


  • Ataxia-telangiectasia
  • Insulin-like growth factor I receptor
  • Nijmegen breakage syndrome
  • Radiosensitivity

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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