Papers

Aug, 2007

Ornithine decarboxylase antizyme upregulates DNA-dependent protein kinase and enhances the nonhomologous end-joining repair of DNA double-strand breaks in human oral cancer cells

BIOCHEMISTRY
  • Takanori Tsuji
  • ,
  • Miki Katsurano
  • ,
  • Soichiro Ibaragi
  • ,
  • Kaori Shima
  • ,
  • Akira Sasaki
  • ,
  • Guo-fu Hu

Volume
46
Number
31
First page
8920
Last page
8932
Language
English
Publishing type
Research paper (scientific journal)
DOI
10.1021/bi7000328
Publisher
AMER CHEMICAL SOC

Ornithine decarboxylase (ODC) antizyme targets ODC for ubiquitin-independent proteosome degradation, thereby inhibiting polyamine synthesis. It has been shown to regulate DNA methylation and has tumor suppressor activity. Increasing evidence suggested that antizyme may also have ODC-independent functions. Here, we report that antizyme plays a role in DNA double-strand break repairs. A zinc-inducible human antizyme gene expression vector was transfected into UM1 human oral squamous cancer cells that do not express endogenous antizyme. The resultant upregulated genes were screened by cDNA arrays and confirmed by quantitative real-time polymerase chain reaction. DNA-dependent protein kinase including its catalytic subunit DNA-PKcs and regulatory subunit Ku70, two key proteins of the DNA damage repair machinery, was significantly upregulated after ectopic expression of antizyme. Consistently, we found that UM1 cells are sensitive to gamma irradiation and deficient in DNA damage repairs, as shown by radio-sensitivity and Comet assays. Ectopic expression of antizyme increased radio-resistance of UM1 cells and restored their capacity of DNA damage repairs to the level of UM2 cells that have an identical genetic background but express endogenous antizyme. Plasmid end-joining assays confirmed that antizyme enhances the ability of UM1 cells to repair DNA double-strand breaks by the nonhomologous end-joining pathway.

Link information
DOI
https://doi.org/10.1021/bi7000328
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000248439000002&DestApp=WOS_CPL
ID information
  • DOI : 10.1021/bi7000328
  • ISSN : 0006-2960
  • Web of Science ID : WOS:000248439000002

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