DNA Double-Strand Break Repair of Blood Lymphocytes and Normal Tissues Analysed in a Preclinical Mouse Model: Implications for Radiosensitivity Testing

Rübe, Claudia E.; Grudzenski, Saskia; Kühne, Martin; Dong, Xiaorong; Rief, Nicole; Löbrich, Markus; Rübe, Christian

doi:10.1158/1078-0432.ccr-07-5147

Cited by 144 publications

(106 citation statements)

References 50 publications

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“…In contrast to these reports, our γH2AX data showed activation of the DNA damage response pathway and involvement of ATM, even at low doses of radiation. 33 Nakamura et al 34 also demonstrated significant and dosedependent numbers of γH2AX foci in A-T cells, suggesting that DNA damage was not completely repaired during low-dose radiation. These findings go in line with Short et al, who found that ATM-dependent signaling to downstream targets, such as TP53, CHK1 and CHK2, occurs even at low doses of 0.2 Gy IR.…”

Section: Discussionmentioning

confidence: 99%

Low-dose irradiation prior to bone marrow transplantation results in ATM activation and increased lethality in Atm-deficient mice

Pietzner¹,

Merscher²,

Baer³

et al. 2016

Bone Marrow Transplant

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Ataxia telangiectasia is a genetic instability syndrome characterized by neurodegeneration, immunodeficiency, severe bronchial complications, hypersensitivity to radiotherapy and an elevated risk of malignancies. Repopulation with ATM-competent bone marrow-derived cells (BMDCs) significantly prolonged the lifespan and improved the phenotype of Atm-deficient mice. The aim of the present study was to promote BMDC engraftment after bone marrow transplantation using low-dose irradiation (IR) as a coconditioning strategy. Atm-deficient mice were transplanted with green fluorescent protein-expressing, ATM-positive BMDCs using a clinically relevant non-myeloablative host-conditioning regimen together with TBI (0.2-2.0 Gy). IR significantly improved the engraftment of BMDCs into the bone marrow, blood, spleen and lung in a dose-dependent manner, but not into the cerebellum. However, with increasing doses, IR lethality increased even after low-dose IR. Analysis of the bronchoalveolar lavage fluid and lung histochemistry revealed a significant enhancement in the number of inflammatory cells and oxidative damage. A delay in the resolution of γ-H2AX-expression points to an insufficient double-strand break repair capacity following IR with 0.5 Gy in Atmdeficient splenocytes. Our results demonstrate that even low-dose IR results in ATM activation. In the absence of ATM, low-dose IR leads to increased inflammation, oxidative stress and lethality in the Atm-deficient mouse model.

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Section: Discussionmentioning

confidence: 99%

Low-dose irradiation prior to bone marrow transplantation results in ATM activation and increased lethality in Atm-deficient mice

Pietzner¹,

Merscher²,

Baer³

et al. 2016

Bone Marrow Transplant

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“…Third, most cell lines in culture exhibit high background foci levels, which make it difficult to analyze DSB repair after low doses in vitro (26). Thus, we refined our previously published methodological approach to investigate DSB repair after low radiation doses in various tissues of irradiated mice (34). Using the analysis of 53BP1 and γ-H2AX foci in tissue sections of the heart, small intestine, and kidney, we were able to show that mice that underwent whole-body irradiation with 10 mGy fail to repair DSBs efficiently.…”

Section: Discussionmentioning

confidence: 99%

“…The induction yield of about 7 foci per cell per 1 Gy at 10 min post-IR is similar to that of our previous study (34) but substantially lower than the level of 15-20 foci per 1 Gy typically observed for human cells in culture (28). We have previously suggested that this difference may reflect that mouse cells have a 20% lower DNA content than human cells, that additional foci loss can occur during the time necessary to retrieve and fix the organs, and that foci scoring in a cross-section of cells embedded in a tissue sample will significantly underestimate the true foci numbers (34). The results for γ-H2AX foci were slightly more variable than for 53BP1 foci but confirmed our finding that foci in tissues are induced linearly with a dose between 10 mGy and 1 Gy (about 0.07, 0.6, and 8 γ-H2AX foci per cell at 10 min after 10 mGy, 100 mGy, or 1 Gy, respectively) (Fig.…”

Section: Pretreatment Of Confluent Primary Human Fibroblasts With H 2mentioning

confidence: 92%

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Inducible response required for repair of low-dose radiation damage in human fibroblasts

Grudzenski

Raths

Conrad

et al. 2010

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

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130

115

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Ionizing radiation (IR) induces a variety of DNA lesions among which DNA double-strand breaks (DSBs) are the biologically most significant. It is currently unclear if DSB repair is equally efficient after low and high doses. Here, we use γ-H2AX, phospho-ATM (pATM), and 53BP1 foci analysis to monitor DSB repair. We show, consistent with a previous study, that the kinetics of γ-H2AX and pATM foci loss in confluent primary human fibroblasts are substantially compromised after doses of 10 mGy and lower. Following 2.5 mGy, cells fail to show any foci loss. Strikingly, cells pretreated with 10 μM H 2 O 2 efficiently remove all γ-H2AX foci induced by 10 mGy. At the concentration used, H 2 O 2 produces single-strand breaks and base damages via the generation of oxygen radicals but no DSBs. Moreover, 10 μM H 2 O 2 up-regulates a set of genes that is also up-regulated after high (200 mGy) but not after low (10 mGy) radiation doses. This suggests that low radical levels induce a response that is required for the repair of radiation-induced DSBs when the radiation damage is too low to cause the induction itself. To address the in vivo significance of this finding, we established γ-H2AX and 53BP1 foci analysis in various mouse tissues. Although mice irradiated with 100 mGy or 1 Gy show efficient γ-H2AX and 53BP1 foci removal during 24 h post-IR, barely any foci loss was observed after 10 mGy. Our data suggest that the cellular response to DSBs is substantially different for low vs. high radiation doses.

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“…Kinetics of disappearance of the Á-H2AX foci in lymphocytes is representative for DNA DSB repair in other tissues. This has been demonstrated by means of mouse strains carrying subtle polymorphisms or mutations in genes involved in DNA DSB repair (32).…”

Section: Discussionmentioning

confidence: 99%

Prediction of late normal tissue complications in RT treated gynaecological cancer patients: Potential of the γ-H2AX foci assay and association with chromosomal radiosensitivity

Werbrouck

Ruyck²,

Beels³

et al. 2009

Oncol Rep

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Abstract. In the present study, the Á-H2AX assay was investigated as a predictive test for the development of late normal tissue complications. Therefore, phosphorylated histone H2AX (Á-H2AX) foci were scored in peripheral blood T-lymphocytes of gynaecological radiotherapy patients, irradiated in vitro with a high dose rate (HDR) and a low dose rate (LDR) protocol. The G 2 chromatid break assay was used to compare chromosomal radiation sensitivity with DNA doublestrand-break (DSB) repair capacity. Late normal tissue reactions were scored according to the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 scale. In our analyses, no differences in foci kinetics were found between the non to mild and moderate to severe patient groups after HDR irradiation. Furthermore, no relation was observed between the level of residual Á-H2AX foci and CTC score after LDR irradiation. On the contrary, the number of chromatid breaks was associated with late clinical radiation sensitivity. Comparison of G 2 chromatid break assay data with the residual number of radiationinduced foci after LDR irradiation and repair times after HDR irradiation showed no relationship between the assays. From this study we can conclude that scoring of Á-H2AX foci after in vitro irradiation of isolated T-lymphocytes of patients is not predictive for late radiotoxicity. This applies as well to the assessment of the repair kinetics after an HDR dose as to the determination of the number of residual foci after a LDR dose.

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DNA Double-Strand Break Repair of Blood Lymphocytes and Normal Tissues Analysed in a Preclinical Mouse Model: Implications for Radiosensitivity Testing

Cited by 144 publications

References 50 publications

Low-dose irradiation prior to bone marrow transplantation results in ATM activation and increased lethality in Atm-deficient mice

Low-dose irradiation prior to bone marrow transplantation results in ATM activation and increased lethality in Atm-deficient mice

Inducible response required for repair of low-dose radiation damage in human fibroblasts

Prediction of late normal tissue complications in RT treated gynaecological cancer patients: Potential of the γ-H2AX foci assay and association with chromosomal radiosensitivity

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