Differential epithelium DNA damage response to ATM and DNA-PK pathway inhibition in human prostate tissue culture

Zhewei Zhang, Zhiming Yang, Sari Jäämaa, Hester Liu, Laxmi G. Pellakuru, Tsuyoshi Iwata, Taija M. Af Hällström, Angelo M. De Marzo, Marikki Laiho

Research output: Contribution to journalArticle

Abstract

The ability of cells to respond and repair DNA damage is fundamental for the maintenance of genomic integrity. Ex vivoculturing of surgery-derived human tissues has provided a significant advancement to assess DNA damage response (DDR) in the context of normal cytoarchitecture in a non-proliferating tissue. Here we assess the dependency of prostate epithelium DDR on ATM and DNA-PKcs, the major kinases responsible for damage detection and repair by nonhomologous end-joining (NHEJ), respectively. DNA damage was caused by ionizing radiation (IR) and cytotoxic drugs, cultured tissues were treated with ATM and DNA-PK inhibitors, and DDR was assessed by phosphorylation of ATM and its targets H2AX and KAP1, a heterochromatin binding protein. Phosphorylation of H2AX and KAP1 was fast, transient and fully dependent on ATM, but these responses were moderate in luminal cells. In contrast, DNA-PKcs was phosphorylated in both luminal and basal cells, suggesting that DNA-PK-dependent repair was activated also in the luminal cells despite the diminished H2AX and KAP1 responses. These results indicate that prostate epithelial cell types have constitutively dissimilar responses to DNA damage. We correlate the altered damage response to the differential chromatin state of the cells. These findings are relevant in understanding how the epithelium senses and responds to DNA damage.

Original languageEnglish (US)
Pages (from-to)3545-3553
Number of pages9
JournalCell Cycle
Volume10
Issue number20
DOIs
StatePublished - Oct 31 2011

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Keywords

  • ATM
  • DNA damage
  • DNA-PK
  • Prostate
  • γH2AX

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology

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