UV-induced replication arrest in the xeroderma pigmentosum variant leads to DNA double-strand breaks, γ-H2AX formation, and Mre11 relocalization

Limoli, Charles L.; Giedzinski, Erich; Bonner, William M.; Cleaver, James E.

doi:10.1073/pnas.231611798

Cited by 199 publications

(164 citation statements)

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“…6). As noted with angelicin and UVA treatment, while γ-H2AX levels were barely detectable in GM637 and XP-F cells, XP-A cells formed detectable levels by 9 h following UVC, consistent with unrepaired ultraviolet photoproducts that arrest replication leading to DSB [42].…”

Section: Uvc Radiation Weakly Induces γ-H2axsupporting

confidence: 56%

“…At 5 kJ/m 2 , the absolute number of crosslinks is lower and the relative ratio of monoadducts to crosslinks is higher than at 20 kJ/m 2 UVA [9,41]. γ-H2AX was barely detectable at 1.5 and 3 h following HMT and UVA treatment, but increased monotonically over 9 h. These results contrast with the almost immediate appearance of γ-H2AX following ionizing radiation [35,42] (Fig. 1) and are consistent with the generation of DSB not as an immediate DNA lesion of HMT photoadducts but rather as an intermediate in response to ICL.…”

Section: Uva Dose-and Time-dependence Of γ-H2ax Formation Due To Iclmentioning

confidence: 81%

“…Since XP-A cells are completely NERdeficient, it is likely that the low levels of γ-H2AX reflect DSB that occur in those cells that are replicating and whose replication forks are stalled at these lesions [42,45]. The absence of γ-H2AX formation following non-ICL DNA lesions in XP-F cells that are also NERdeficient further suggests that XPF may be important for DSB formation following replication fork arrest at any DNA lesion and not just at ICL.…”

Section: Discussionmentioning

confidence: 99%

“…In all cells treated with angelicin and 20 kJ/m 2 UVA, γ-H2AX levels measured by Western immunoblotting were considerably lower than those observed following identical doses of HMT and UVA, and only increased significantly above background in XP-A cells by 9 h following treatment, consistent with minimal ICL and DSB formation following angelicin and UVA treatment. Since angelicin and UVA do not result in ICL, it is possible that the small amount of γ-H2AX observed in NER-deficient XP-A cells at 9 h post-UVA represent DSB formed by collapsed replication forks arrested at unrepaired monoadducts [42,45]. Neither GM637 nor NER-deficient XP-F cells formed appreciable amounts of γ-H2AX following angelicin and UVA treatment.…”

Section: Angelicin Monoadducts Only Weakly Induce γ-H2axmentioning

confidence: 98%

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γ-H2AX formation in response to interstrand crosslinks requires XPF in human cells

Mogi

2006

DNA Repair

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To further define the molecular mechanisms involved in processing interstrand crosslinks, we monitored the formation of phosphorylated histone H2AX (γ-H2AX), which is generated in chromatin near double strand break sites, following DNA damage in normal and repair-deficient human cells. Following treatment with a psoralen derivative and ultraviolet A radiation doses that produce significant numbers of crosslinks, γ-H2AX levels in nucleotide excision repair-deficient XP-A fibroblasts (XP12RO-SV) increased to levels that were twice those observed in normal control GM637 fibroblasts. A partial XPA revertant cell line (XP129) that is proficient in crosslink removal, exhibited reduced γ-H2AX levels that were intermediate between those of GM637 and XP-A cells. XP-F fibroblasts (XP2YO-SV and XP3YO) that are also repair-deficient exhibited γ-H2AX levels below even control fibroblasts following treatment with psoralen and ultraviolet A radiation. Similarly, another crosslinking agent, mitomycin C, did not induce γ-H2AX in XP-F cells, although it did induce equivalent levels of γ-H2AX in XPA and control GM637 cells. Ectopic expression of XPF in XP-F fibroblasts restored γ-H2AX induction following treatment with crosslinking agents. Angelicin, a furocoumarin which forms only monoadducts and not crosslinks following ultraviolet A radiation, as well as ultraviolet C radiation, resulted only in weak induction of γ-H2AX in all cells, suggesting that the double strand breaks observed with psoralen and ultraviolet A treatment result preferentially following crosslink formation. These results indicate that XPF is required to form γ-H2AX and likely double strand breaks in response to interstrand crosslinks in human cells. Furthermore, XPA may be important to allow psoralen interstrand crosslinks to be processed without forming a double strand break intermediate.

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Section: Uvc Radiation Weakly Induces γ-H2axsupporting

confidence: 56%

Section: Uva Dose-and Time-dependence Of γ-H2ax Formation Due To Iclmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Angelicin Monoadducts Only Weakly Induce γ-H2axmentioning

confidence: 98%

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γ-H2AX formation in response to interstrand crosslinks requires XPF in human cells

Mogi

2006

DNA Repair

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“…In addition, ROS are involved in generating DNA single strand (ss) breaks (Kielbassa et al, 1997). If ss breaks are not repaired during the G 1 phase of the cell cycle they can generate double strand (ds) breaks during S-phase which then can result in chromosomal aberrations such as amplifications, deletions or translocations (for review see Limoli et al, 2002;Thompson and Limoli, 2003); all hallmarks of skin carcinomas. Interestingly, CPDs can also cause ds breaks in S-phase (Garinis et al, 2005), suggesting that they too may contribute to chromosomal instability.…”

Section: Introductionmentioning

confidence: 99%

UVA radiation causes DNA strand breaks, chromosomal aberrations and tumorigenic transformation in HaCaT skin keratinocytes

et al. 2008

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The role of UVA-radiation-the major fraction in sunlight-in human skin carcinogenesis is still elusive. We here report that different UVA exposure regime (4 Â 5 J/cm 2 per week or 1 Â 20 J/cm 2 per week) caused tumorigenic conversion (tumors in nude mice) of the HaCaT skin keratinocytes. While tumorigenicity was not associated with general telomere shortening, we found new chromosomal changes characteristic for each recultivated tumor. Since this suggested a nontelomere-dependent relationship between UVA irradiation and chromosomal aberrations, we investigated for alternate mechanisms of UVA-dependent genomic instability. Using the alkaline and neutral comet assay as well as c-H2AX foci formation on irradiated HaCaT cells (20-60 J/cm 2 ), we show a dosedependent and long lasting induction of DNA single and double (ds) strand breaks. Extending this to normal human skin keratinocytes, we demonstrate a comparable damage response and, additionally, a significant induction and maintenance of micronuclei (MN) with more acentric fragments (indicative of ds breaks) than entire chromosomes particularly 5 days post irradiation. Thus, physiologically relevant UVA doses cause long-lasting DNA strand breaks, a prerequisite for chromosomal aberration that most likely contribute to tumorigenic conversion of the HaCaT cells. Since normal keratinocytes responded similarly, UVA may likewise contribute to the complex karyotype characteristic for human skin carcinomas.

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Ultraviolet Radiation Carcinogenesis

Cleaver

Mitchell

2017

Holland‐Frei Cancer Medicine

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Overview Skin carcinogenesis from solar ultraviolet (UV) exposure is initiated by UV photoproducts formed in the DNA of precursor cells that give rise to squamous cell carcinomas, basal cell carcinomas, and melanomas. These photoproducts consist of dimers between adjacent pyrimidines that are repaired by nucleotide excision repair (NER). Two branches of NER differ in mechanisms of damage recognition: in global genome repair (GGR), damage is recognized in nontranscribed DNA by the DDB2 and XPC proteins; in transcription‐coupled repair (TCR), damage is recognized by arrest of the transcribing RNA polymerase at damaged sites. The T = C photoproduct is the predominant mutagenic product which, if unrepaired, gives rise to C to T or CC to TT mutations through replication by the low‐fidelity polymerase Pol H. TCR reduces the mutation frequency in regions of transcription, in comparison to the rest of the genome subject to GGR. Deficiencies in GGR in the human disease xeroderma pigmentosum cause earlier onset and increased rates of skin cancer, which often contain UV‐type mutations in genes that are rarely mutated in the general population. Deficiencies in TCR in the human disease Cockayne syndrome are associated with photosensitivity, developmental, and neurological disorders, but no cancer has been reported.

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UV-induced replication arrest in the xeroderma pigmentosum variant leads to DNA double-strand breaks, γ-H2AX formation, and Mre11 relocalization

Abstract: UV-induced replication arrest in the xeroderma pigmentosum variant (XPV) but not in normal cells leads to an accumulation of theDNA damage ͉ x-ray ͉ S-phase ͉ checkpoints ͉ recombination

Cited by 199 publications

References 65 publications

γ-H2AX formation in response to interstrand crosslinks requires XPF in human cells

γ-H2AX formation in response to interstrand crosslinks requires XPF in human cells

UVA radiation causes DNA strand breaks, chromosomal aberrations and tumorigenic transformation in HaCaT skin keratinocytes

Ultraviolet Radiation Carcinogenesis

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