Phosphorylation of histone H2AX as a measure of radiosensitivity

Olive, Peggy L.; Banáth, Judit P.

doi:10.1016/j.ijrobp.2003.09.028

Cited by 265 publications

(181 citation statements)

References 16 publications

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“…H2AX, has attracted particular attention. Upon irradiation or other exogenous stress, numerous molecules of H2AX are rapidly phosphorylated at the flanking sites of chromatin where DSBs have been induced forming the so-called cH2AX nuclear foci [21][22][23][24][25][26][27][28][29][30][31]. The fact that phosphorylation remains at the sites of DSBs until the end of repair processes before the foci are dephosphorylated [32][33][34][35][36] facilitates the study of foci disappearance along with the quantitative evaluation of residual DSBs [20,21,23,29,[37][38][39][40][41].…”

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confidence: 99%

“…The fact that phosphorylation remains at the sites of DSBs until the end of repair processes before the foci are dephosphorylated [32][33][34][35][36] facilitates the study of foci disappearance along with the quantitative evaluation of residual DSBs [20,21,23,29,[37][38][39][40][41]. In several studies both these endpoints have been correlated with cellular radiation sensitivity in vitro and in vivo either in tumour or normal tissue samples [20,21,23,28,29,31,37,39,41,42]. Taking together, the cH2AX assay is simple, sensitive and straightforward method to quantify DSBs in cells and tissues and therefore promising for translation into clinical trials.…”

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confidence: 99%

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Residual γH2AX foci after ex vivo irradiation of patient samples with known tumour-type specific differences in radio-responsiveness

Menegakis¹,

Colle²,

Yaromina³

et al. 2015

Radiotherapy and Oncology

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known differences in radiation response, i.e. radiosensitive types such as seminomas and resistant types as chondrosarcomas. We hypothesized that the number of residual cH2AX foci corresponds to the expected tumour radiation sensitivity. In addition, in order to enhance clinical practicability for future studies the data were used for simulations to test the robustness of the method when omitting dose levels. Materials and methods Collection and cultivation of patient-derived tumour specimensThe study has been approved by the Ethics Committee of the Medical Faculty of the University of Tübingen (426/2013BO1). All the patients included in the study were untreated prior to surgical procedure. During collection and cultivation tumour tissues were kept in Dulbecco's MEM culture medium supplemented with 2% HEPES, 1% Na-pyruvate, 1% non-essential amino acids, 1% penicillin streptomycin (all Biochrom AG, Berlin, Germany) and 10% FBS (PAN Biotech GmbH, Aidenbach, Germany). Fresh tumour material was retrieved from surgical specimens and placed in 50 ml Falcon tubes (Becton Dickinson International, Heidelberg, Germany) containing 15 ml culture medium. Tumour specimens were transported to the laboratory and subsequently cut manually with the use of surgical forceps (BD027R, B. BRAUN, Aesculap, Tuttlingen, Germany) and scalpels (FEATHER Safety Razor Co., Ltd., Osaka, Japan Number 23) into approximately 2-3 mm slices before being placed in petri dishes (3.5 cm diameter) coated with a 1.5% agarose layer (A9539, Sigma-Aldrich, Germany) containing 3 ml culture media. During all incubation times the petri-dishes were kept in 95% humidified atmosphere at 37 _C and 5% CO2. For the purpose of the study tumour material from a total of 25 patient tumours with 10 different tumour histologies was collected (Table 1; n = 3 seminomas, n = 1 chondrosarcoma, n = 3 urinary bladder carcinomas (Ca), n = 3 colorectal Ca (2 colon Ca + 1 rectum), n = 3 breast Ca, n = 1 hepatocellular Ca, n = 3 renal cell Ca, n = 3 prostate Ca, n = 4 glioblastoma multiforme (GBM) and n = 2 cervix Ca). In one GBM patient, the specimen was removed from the analysis because in the 0 Gy sample there was no viable tumour part (based on morphological criteria and BrdU positivity) and no estimation of the background foci could be performed. Histology and selection of malignant cells for analysis were confirmed by an experienced pathologist (M.S.).Experimental design for evaluation of cH2AX foci in ex vivo irradiated patient-derived tumour specimensThe experimental design has been previously described [45]. Briefly, after initial cultivation for 24 h, the tumour specimens were irradiated typically with 0, 2, 4, 6, 8 Gy single doses (200 kV, RS225 research system Gulmay Medical LTD, Surrey, England; 15 mA; 0.5 mm Cu; dose rate _1 Gy/min). In two tumours, additional doses were delivered to the seminoma sample (#1) doses of 3 and 5 Gy and GBM (#1) 10

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confidence: 99%

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confidence: 99%

Residual γH2AX foci after ex vivo irradiation of patient samples with known tumour-type specific differences in radio-responsiveness

Menegakis¹,

Colle²,

Yaromina³

et al. 2015

Radiotherapy and Oncology

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“…Indeed, HR operates only in the S/G2 phase, since it needs accessible homologous chromatin regions (21) and the activation of cyclin-dependent kinases, down regulated in G1 phase, is required for HR (11). Moreover, a small number of errors does not seem to be necessarily repaired immediately and the presence of γ-H2AX foci is bound to stay until further repair (error corrections) (9).…”

Section: Discussionmentioning

confidence: 99%

“…Improperly repaired DSB may result in DNA sequence integrity alterations or to cell death (6)(7)(8)(9)(10)(11). While excessive cell death may lead to embryonic malformations and growth retardation, persisting alterations in DNA may be transmitted to the daughter cells of the embryos thereby increasing the risk for postnatal cancer or genetic diseases.…”

Section: Introductionmentioning

confidence: 99%

X-irradiation induces cell death in fetal fibroblasts

et al. 2012

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“…19,30 Phosphorylation of H2AX to form γH2AX is one of the earliest events following the induction of DSBs and has an important role in recruiting repair factors to nuclear foci. [60][61][62] Nuclear γH2AX foci extend over a megabase range of chromatin from the site of the DSB, and γH2AX expression has been used as a sensitive marker of ionizing radiation induced DSBs. [60][61][62] The findings, including those from the previous study with VPA 19 indicate that HDAC inhibitors enhance radiationinduced expression of γH2AX foci, providing further evidence that the radiation sensitizing effect of HDAC inhibitors may be due to inhibition of DSB repair.…”

Section: Discussionmentioning

confidence: 99%

The Epigenetic Modifier, Valproic Acid, Enhances Radiation Sensitivity

Karagiannis¹,

Harikrishnan²,

El‐Osta³

2006

Epigenetics

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Valproic acid is an established therapeutic for a variety of seizure disorders and in certain cases for depression and anxiety. In addition, valproic acid has been shown to possess histone deacetylase inhibition activity and is currently being investigated as an anti-cancer agent, either alone or in combination with other conventional cancer therapies such as ionizing radiation. In this study, we investigated whether valproic acid modulates cellular responses to radiation in human erythroleukemic, K562 cells. Hyperacetylation of nuclear histones 3 and 4 was used to correlate the effects of valproic acid to inhibition of histone deacetylase activity, clonogenic survival, apoptosis and apoptosis. The findings from the clonogenic survival and caspase induction assays indicated that pretreatment of cells with valproic acid for 24 hours, markedly enhanced radiation induced cell-death and apoptosis in K562 cells, respectively. Mechanisms involving drug-mediated cytotoxicity and changes in cell cycle distribution were associated with the radiation sensitizing properties of valproic acid, particularly at the higher concentrations. Overall, our findings are consistent with the general consensus that HDAC inhibitors efficiently sensitize cancer cells to the effects of ionizing radiation and support the idea of developing clinically relevant combinations of HDAC inhibitors and radiotherapy.

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Phosphorylation of histone H2AX as a measure of radiosensitivity

Cited by 265 publications

References 16 publications

Residual γH2AX foci after ex vivo irradiation of patient samples with known tumour-type specific differences in radio-responsiveness

Residual γH2AX foci after ex vivo irradiation of patient samples with known tumour-type specific differences in radio-responsiveness

X-irradiation induces cell death in fetal fibroblasts

The Epigenetic Modifier, Valproic Acid, Enhances Radiation Sensitivity

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