DNA repair and gene therapy: Implications for translational uses

Limp-Foster, Melissa; Kelley, Mark R.

doi:10.1002/(sici)1098-2280(2000)35:2<71::aid-em1>3.0.co;2-p

Cited by 32 publications

(19 citation statements)

References 77 publications

(65 reference statements)

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“…This has been confirmed for the human T-G mismatch glycosylase that is dislocated by Ape1/ref-1 (48). However, enzymes downstream to hOgg1 may be rate-limiting in human cells (31,49). It would be interesting to determine if increased expression of these downstream enzymes (Ape1/ref-1 and/or ␤-polymerase) will augment cell survival with coexpression of either hOgg1 or Fpg (31).…”

Section: Discussionmentioning

confidence: 90%

Protection of Human Lung Cells against Hyperoxia Using the DNA Base Excision Repair Genes hOgg1 and Fpg

Kobune

et al. 2002

Am J Respir Crit Care Med

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Section: Discussionmentioning

confidence: 90%

Protection of Human Lung Cells against Hyperoxia Using the DNA Base Excision Repair Genes hOgg1 and Fpg

Kobune

et al. 2002

Am J Respir Crit Care Med

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“…They exert anticancer effects by causing DNA alkylation, blocking the normal replication or transcription of DNA, and inducing apoptosis of tumor cells [5][6][7][8][9]. However, due to the presence of intracellular O 6 -alkylguanine-DNA alkyltransferase (AGT), which can repair the alkylation damage caused by such agents, the formation of mono-adducts or lethal dG-dC inter-crosslinks can be blocked, leading to drug resistance [10][11][12][13][14][15]. Therefore, inhibiting AGT activity in tumor cells is of great significance for improving the chemotherapeutic effects of treatment.…”

Section: Introductionmentioning

confidence: 99%

Reductive Activity and Mechanism of Hypoxia- Targeted AGT Inhibitors: An Experimental and Theoretical Investigation

Xiao

Sun

Fan

et al. 2019

IJMS

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O 6 -alkylguanine-DNA alkyltransferase (AGT) is the main cause of tumor cell resistance to DNA-alkylating agents, so it is valuable to design tumor-targeted AGT inhibitors with hypoxia activation. Based on the existing benchmark inhibitor O 6 -benzylguanine (O 6 -BG), four derivatives with hypoxia-reduced potential and their corresponding reduction products were synthesized. A reductase system consisting of glucose/glucose oxidase, xanthine/xanthine oxidase, and catalase were constructed, and the reduction products of the hypoxia-activated prodrugs under normoxic and hypoxic conditions were determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results showed that the reduction products produced under hypoxic conditions were significantly higher than that under normoxic condition. The amount of the reduction product yielded from ANBP (2-nitro-6-(3-amino) benzyloxypurine) under hypoxic conditions was the highest, followed by AMNBP (2-nitro-6-(3-aminomethyl)benzyloxypurine), 2-NBP (2-nitro-6-benzyloxypurine), and 3-NBG (O6-(3-nitro)benzylguanine). It should be noted that although the levels of the reduction products of 2-NBP and 3-NBG were lower than those of ANBP and AMNBP, their maximal hypoxic/normoxic ratios were higher than those of the other two prodrugs. Meanwhile, we also investigated the single electron reduction mechanism of the hypoxia-activated prodrugs using density functional theory (DFT) calculations. As a result, the reduction of the nitro group to the nitroso was proven to be a rate-limiting step. Moreover, the 2-nitro group of purine ring was more ready to be reduced than the 3-nitro group of benzyl. The energy barriers of the rate-limiting steps were 34-37 kcal/mol. The interactions between these prodrugs and nitroreductase were explored via molecular docking study, and ANBP was observed to have the highest affinity to nitroreductase, followed by AMNBP, 2-NBP, and 3-NBG. Interestingly, the theoretical results were generally in a good agreement with the experimental results. Finally, molecular docking and molecular dynamics simulations were performed to predict the AGT-inhibitory activity of the four prodrugs and their reduction products. In summary, simultaneous consideration of reduction potential and hypoxic selectivity is necessary to ensure that such prodrugs have good hypoxic tumor targeting. This study provides insights into the hypoxia-activated mechanism of nitro-substituted prodrugs as AGT inhibitors, which may contribute to reasonable design and development of novel tumor-targeted AGT inhibitors. Figure 2. Typical selected reaction monitoring (SRM) ion chromatograms of ABG, AMBG, and O 6 -BG obtained from the four prodrugs (3-NBG, 2-NBP, ANBP, and AMNBP) and the internal standard D6-O 6 -BG. The prodrugs were reduced in normoxic or hypoxic condition. (A) Control sample without 3-NBG and ANBP. (B) Reduction of 3-NBG and ANBP under normoxic conditions. (C) Reduction of 3-NBG and ANBP under hypoxic conditions. (D) Control...

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“…genomic integrity | DNA repair | nonhomologous end-joining | super-resolution microscopy | single-molecule FRET C hromosomal double-strand breaks (DSBs), considered the most cytotoxic form of DNA damage, occur as a result of normal cellular processes (1, 2) as well as cancer therapies (3)(4)(5). The cellular DNA damage response (DDR) and repair pathways responsible for maintaining genomic integrity are highly regulated and synchronized processes, both temporally and spatially, involving the coordinated recruitment, assembly, and disassembly of numerous macromolecular complexes (6,7).…”

mentioning

confidence: 99%

Organization and dynamics of the nonhomologous end-joining machinery during DNA double-strand break repair

Reid

Keegan

Leo‐Macias

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

154

168

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Nonhomologous end-joining (NHEJ) is a major repair pathway for DNA double-strand breaks (DSBs), involving synapsis and ligation of the broken strands. We describe the use of in vivo and in vitro single-molecule methods to define the organization and interaction of NHEJ repair proteins at DSB ends. Super-resolution fluorescence microscopy allowed the precise visualization of XRCC4, XLF, and DNA ligase IV filaments adjacent to DSBs, which bridge the broken chromosome and direct rejoining. We show, by singlemolecule FRET analysis of the Ku/XRCC4/XLF/DNA ligase IV NHEJ ligation complex, that end-to-end synapsis involves a dynamic positioning of the two ends relative to one another. Our observations form the basis of a new model for NHEJ that describes the mechanism whereby filament-forming proteins bridge DNA DSBs in vivo. In this scheme, the filaments at either end of the DSB interact dynamically to achieve optimal configuration and end-to-end positioning and ligation.genomic integrity | DNA repair | nonhomologous end-joining | super-resolution microscopy | single-molecule FRET C hromosomal double-strand breaks (DSBs), considered the most cytotoxic form of DNA damage, occur as a result of normal cellular processes (1, 2) as well as cancer therapies (3-5). The cellular DNA damage response (DDR) and repair pathways responsible for maintaining genomic integrity are highly regulated and synchronized processes, both temporally and spatially, involving the coordinated recruitment, assembly, and disassembly of numerous macromolecular complexes (6, 7). In mammalian cells, nonhomologous end-joining (NHEJ) is the primary DSB repair pathway; it is active throughout the cell cycle and is crucial for viability. Dysfunctional NHEJ is associated with several clinical conditions, including LIG4 syndrome and severe combined immunodeficiency (1,8). Despite its importance, however, the details of how the NHEJ complex assembles at DSBs, brings together a pair of breaks, and organizes subsequent catalytic repair steps remain unknown.In NHEJ, DSBs are initially recognized by the Ku 70/80 heterodimer (Ku), which encircles dsDNA ends (Ku:DNA) and serves as a molecular scaffold for recruitment of DNA-dependent protein kinase catalytic subunit (DNA-PKcs), XRCC4 (X-ray repair cross-complementing protein 4), XLF (XRCC4 like factor), and DNA ligase IV (LigIV) (1,(9)(10)(11)(12)(13)(14). Previous NHEJ models suggested that after binding of Ku to DNA ends, DNA-PKcs binds Ku:DNA to form a DNA-PK holoenzyme and bridges the broken ends (15-18); however, recent experiments indicate that DNAPKcs may have different roles in NHEJ, such as the stabilization of core NHEJ factors, recruitment and retention of accessory factors, involvement in the DDR signaling cascade, and repair of complex and clustered . In addition, recent structural studies have shown that XRCC4 and XLF form filamentous structures in vitro (26-28). Whether such filaments mediate repair in vivo has not yet been determined.Our present understanding of the cellular NHEJ response to DSBs ...

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DNA repair and gene therapy: Implications for translational uses

Cited by 32 publications

References 77 publications

Protection of Human Lung Cells against Hyperoxia Using the DNA Base Excision Repair Genes hOgg1 and Fpg

Protection of Human Lung Cells against Hyperoxia Using the DNA Base Excision Repair Genes hOgg1 and Fpg

Reductive Activity and Mechanism of Hypoxia- Targeted AGT Inhibitors: An Experimental and Theoretical Investigation

Organization and dynamics of the nonhomologous end-joining machinery during DNA double-strand break repair

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