TET1 regulates DNA repair in human glial cells

Katherine J. Kuhns, Hernando Lopez-Bertoni, Jonathan B. Coulter, Joseph Bressler

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Article number114646
JournalToxicology and Applied Pharmacology
Volume380
DOIs
StatePublished - Oct 1 2019

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Neuroglia
DNA Repair
Repair
DNA
Ionizing radiation
Ionizing Radiation
Topoisomerase Inhibitors
DNA Breaks
Glioblastoma
Cell Line
Joining
Dioxygenases
Comet Assay
Survival
Genomic Instability
Cytotoxicity
Brain Neoplasms
Glioma
DNA Damage
Assays

Keywords

  • DNA-PK
  • Human glioma
  • Ionizing radiation
  • Non homologous DNA repair
  • TET1

ASJC Scopus subject areas

  • Toxicology
  • Pharmacology

Cite this

TET1 regulates DNA repair in human glial cells. / Kuhns, Katherine J.; Lopez-Bertoni, Hernando; Coulter, Jonathan B.; Bressler, Joseph.

In: Toxicology and Applied Pharmacology, Vol. 380, 114646, 01.10.2019.

Research output: Contribution to journalArticle

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