Human Polynucleotide Kinase Participates in Repair of DNA Double-Strand Breaks by Nonhomologous End Joining but not Homologous Recombination
- 15 July 2007
- journal article
- Published by American Association for Cancer Research (AACR) in Cancer Research
- Vol. 67 (14), 6619-6625
- https://doi.org/10.1158/0008-5472.can-07-0480
Abstract
Human polynucleotide kinase (hPNK) is a bifunctional enzyme possessing a 5′-DNA kinase activity and a 3′-phosphatase activity. Studies based on cell extracts and purified proteins have indicated that hPNK can act on single-strand breaks and double-strand breaks (DSB) to restore the termini to the chemical form required for further action by DNA repair polymerases and ligases (i.e., 5′-phosphate and 3′-hydroxyl termini). These studies have revealed that hPNK can bind to XRCC4, and as a result, hPNK has been implicated as a participant in the nonhomologous end joining (NHEJ) pathway for DSB repair. We sought to confirm the role of hPNK in NHEJ in the cellular setting using a genetic approach. hPNK was stably down-regulated by RNA interference expression in M059K glioblastoma cells, which are NHEJ positive, and M059J cells, which are NHEJ deficient due to a lack of DNA-PK catalytic subunit (DNA-PKcs). Whereas depletion of hPNK significantly sensitized M059K cells to ionizing radiation, no additional sensitization was conferred to M059J cells, clearly implying that hPNK operates in the same DNA repair pathway as DNA-PKcs. On the other hand, depletion of hPNK did not increase the level of sister chromatid exchanges, indicating that hPNK is not involved in the homologous recombination DSB repair pathway. We also provide evidence that the action of hPNK in the repair of camptothecin-induced topoisomerase 1 “dead-end” complexes is independent of DNA-PKcs and that hPNK is not involved in the nucleotide excision repair pathway. [Cancer Res 2007;67(14):6619–25]This publication has 52 references indexed in Scilit:
- Emerging cancer therapeutic opportunities target DNA-repair systemsTrends in Pharmacological Sciences, 2006
- Involvement of Polynucleotide Kinase in a Poly(ADP-ribose) Polymerase-1-dependent DNA Double-strand Breaks Rejoining PathwayJournal of Molecular Biology, 2006
- DNA Double-Strand Break Repair: A Relentless Hunt Uncovers New PreyCell, 2006
- Cellular processing of platinum anticancer drugsNature Reviews Drug Discovery, 2005
- Deficiency in the Catalytic Subunit of DNA-Dependent Protein Kinase Causes Down-Regulation of ATMCancer Research, 2005
- Action of human apurinic endonuclease (Ape1) on C1′-oxidized deoxyribose damage in DNADNA Repair, 2003
- DNA double-strand breaks associated with replication forks are predominantly repaired by homologous recombination involving an exchange mechanism in mammalian cellsJournal of Molecular Biology, 2001
- Comparison of initial yields of DNA-to-protein crosslinks and single-strand breaks induced in cultured human cells by far- and near-ultraviolet light, blue light and X-raysMutation research. Reviews in mutation research, 1991
- Detection of DNA strand breaks in Escherichia coli treated with platinum(IV) antitumor compoundsChemico-Biological Interactions, 1990
- Investigations into the mechanisn of action of antitumour platinum compounds: Time- and dose-dependent changes in the alkaline sucrose gradient sedimentation profiles of DNA from hamster cells treated with cis-platinum(II) diamminedichlorideChemico-Biological Interactions, 1975