ATM regulates a RASSF1A-dependent DNA damage response

Garth Hamilton1, Karen S Yee, Simon Scrace

  • 1Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.

Current Biology : CB
|December 8, 2009
PubMed

Insights

Epigenetic silencing of RASSF1A or mutations disabling its ATM phosphorylation site are frequent in cancer. This disrupts a novel DNA damage pathway, reducing apoptosis and therapy response.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Epigenetics

Background:

  • Hypermethylation of the RASSF1 promoter is common in cancer, leading to RASSF1A loss and reduced DNA-damaging therapy response.
  • RASSF1A normally promotes apoptosis via MST2/LATS1 kinases, stabilizing the YAP1/p73 complex.

Purpose of the Study:

  • To identify a novel DNA damage signaling pathway involving RASSF1A.
  • To investigate the role of ATM in RASSF1A activation and its implications in cancer.

Main Methods:

  • Investigated the link between DNA damage signaling and RASSF1A using cell lines.
  • Analyzed RASSF1A phosphorylation by ATM and its effect on downstream signaling.
  • Examined RASSF1A polymorphisms in tumor cell lines and their association with therapy resistance.

Main Results:

  • DNA damage induces RASSF1A phosphorylation by ATM at Ser131, activating MST2/LATS1 and stabilizing p73.
  • Lung and ovarian tumors with retained RASSF1A expression often have Ser131 polymorphisms.
  • The S131F polymorphism confers resistance to DNA-damaging agents.

Conclusions:

  • A novel ATM-RASSF1A DNA damage pathway exists and is frequently disrupted in cancer.
  • Disruption occurs via RASSF1 epigenetic silencing or ATM phosphorylation site mutations.
  • This pathway disruption contributes to tumor progression and therapy resistance.

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