2. Academic Validation
  3. TET1 regulates DNA repair in human glial cells

TET1 regulates DNA repair in human glial cells

  • Toxicol Appl Pharmacol. 2019 Oct 1;380:114646. doi: 10.1016/j.taap.2019.114646.
Katherine J Kuhns 1,  Hernando Lopez-Bertoni 2,  Jonathan B Coulter 3,  Joseph P Bressler 4
Affiliations

Affiliations

  • 1 Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Johns Hopkins School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
  • 2 Department of Neurology, Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
  • 3 Department of Neurology, Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD 21205, USA; Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Johns Hopkins School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
  • 4 Department of Neurology, Hugo W. Moser Research Institute at Kennedy Krieger, 707 N. Broadway, Baltimore, MD 21205, USA; Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Johns Hopkins School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA. Electronic address: bressler@kennedykrieger.org.
PMID: 31278917 DOI: 10.1016/j.taap.2019.114646
Abstract

Glioblastomas are the most aggressive of malignant brain cancers with a median patient survival of approximately 18 months. We recently demonstrated that Tet methylcytosine dioxygenase 1(TET1) is involved in cellular responses to ionizing radiation (IR) in glial-, glioblastoma-, and non-tumor-derived cells. This study used a lentiviral-mediated knockdown of TET1 to further dissect the contribution of TET1 to the DNA damage response in glial cell lines by evaluating its role in DNA repair. TET1-deficient glial cell lines displayed attenuated cytotoxicity compared to non-targeted knockdown after treatment with IR but these differences were not observed between control and TET1 deficient in response to inhibitors of Na+/K+-ATPase. Additionally, the percentage of glial cells displaying γH2A.x foci was greatly reduced in TET1-deficient glial cells compared to non-targeted knockdown conditions in response to IR and Topoisomerase inhibitors. We also observed a lower percentage and a delay in 53BP1 foci formation, a marker of non-homologous end-joining, in response to IR and Topoisomerase inhibitors in TET1-deficient glial cells. DNA-PK, another marker of non-homologous end-joining, was also lower in TET1-deficient glial cell lines. Interestingly, TET1-deficient glial cells displayed higher numbers of DNA strand breaks compared to control cells and repaired DNA breaks less efficiently in Comet assays. We suggest that attenuated DNA repair in TET1 deficient gliomas leads to genomic instability, which underlies poor patient survival.

Keywords

DNA-PK; Human glioma; Ionizing radiation; Non homologous DNA repair; TET1.

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