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 language | English (US) |
|---|---|
| Article number | 114646 |
| Journal | Toxicology and Applied Pharmacology |
| Volume | 380 |
| DOIs | |
| State | Published - Oct 1 2019 |
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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 journal › Article
}
TY - JOUR
T1 - TET1 regulates DNA repair in human glial cells
AU - Kuhns, Katherine J.
AU - Lopez-Bertoni, Hernando
AU - Coulter, Jonathan B.
AU - Bressler, Joseph
PY - 2019/10/1
Y1 - 2019/10/1
N2 - 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.
AB - 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.
KW - DNA-PK
KW - Human glioma
KW - Ionizing radiation
KW - Non homologous DNA repair
KW - TET1
UR - http://www.scopus.com/inward/record.url?scp=85070204174&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85070204174&partnerID=8YFLogxK
U2 - 10.1016/j.taap.2019.114646
DO - 10.1016/j.taap.2019.114646
M3 - Article
VL - 380
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
SN - 0041-008X
M1 - 114646
ER -