Does γH2AX foci formation depend on the presence of DNA double strand breaks?

Takahashi, Akio; Ohnishi, Takeo

doi:10.1016/j.canlet.2005.07.016

Cited by 206 publications

(146 citation statements)

References 65 publications

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“…γH2AX has been well reported to be induced in nucleus upon DNA damage in a cell cycle-dependent manner as a downstream target of ATM (MacPhail et al, 2003;Ichijima et al, 2005;Takahashi and Ohnishi, 2005). However, TrkAinduced γH2AX production did not seem to be related to DNA damage-induced ATM activation pathway because there was no autophosphorylation of ATM at serine 1981 in TrkA-induced cells ( Figure 1B).…”

Section: Discussionmentioning

confidence: 89%

“…DNA damage by doxorubicin and ionizing radiation induces autophosphorylation of ATM at Serine 1981 and subsequently activate multiple downstream targets such as p53, histone H2AX, Nbs1, Chk1, and Chk2 Cho et al, 2005). As an early response to DNA damage, H2AX, a derivative of histone H2A, can be phosphorylated at Serine 139 by ATM, other PI-3 kinases such as ATR and DNA-PK (Takahashi and Ohnishi, 2005), and c-Jun NH2-terminal kinase (JNK) (Lu et al, 2006;Sluss and Davis, 2006). This phosphorylated H2AX is generally named γH2AX and detected by its phosphate-specific antibody.…”

Section: Introductionmentioning

confidence: 99%

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Cytosolic accumulation of γH2AX is associated with tropomyosin-related kinase A-induced cell death in U2OS cells

Jung

Kim

2008

Exp Mol Med

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Tropomyosin-related kinase A (TrkA) plays an important role in cell survival, differentiation, and apoptosis in various neuronal and nonneuronal cell types. Here we show that TrkA overexpression by the Tet-On system mimics NGF-mediated activation pathways in the absence of nerve growth factor (NGF) stimulation in U2OS cells. In addition, p53 upregulation upon DNA damage was inhibited by TrkA, and p21 was upregulated by TrkA in a p53-independent manner. TrkA overexpression caused cell death by interrupting cell cycle progression, and TrkA-induced cell death was diminished in the presence of its specific inhibitor GW441756. Interestingly, TrkA-mediated cell death was strongly related to γH2AX production and poly (ADP-ribose) polymerase cleavage in the absence of DNA damage inducer. In this study, we also reveal that γH2AX production by TrkA is blocked by TrkA kinase inhibitors K-252a and GW441756, and it is also significantly inhibited by JNK inhibitor SP600125. Moreover, reduction of cell viability by TrkA was strongly suppressed by SP600125 treatment, suggesting a critical role of JNK in TrkA-induced cell death. We also found that γH2AX and TrkA were colocalized in cytosol in the absence of DNA damage, and the nuclear localization of γH2AX induced by DNA damage was partly altered to cytosol by TrkA overexpression. Our results suggest that the abnormal cytosolic accumulation of γH2AX is implicated in TrkA-induced cell death in the absence of DNA damage.

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Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Cytosolic accumulation of γH2AX is associated with tropomyosin-related kinase A-induced cell death in U2OS cells

Jung

Kim

2008

Exp Mol Med

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“…[21][22][23][24] Phosphorylation of H2AX is considered to be a specific reporter of DSBs. [15][16][17][25][26][27] Cytometric detection of phosphorylated H2AX combined with analysis of cellular DNA content provides an assay of DNA damage (e.g., induced by genotoxic agents such as some antitumor drugs) in relation to the cell cycle phase. An example of induction of H2AX phosphorylation in cells treated with DNA topoisomerase I inhibitor topotecan (Tpt) is presented in Figure 1.…”

Section: Markers Of Dna Damagementioning

confidence: 99%

Constitutive Histone H2AX Phosphorylation and ATM Activation, the Reporters of DNA Damage by Endogenous Oxidants

Tanaka

Halicka²,

Huang³

et al. 2006

Cell Cycle

190

197

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DNA in live cells undergoes continuous oxidative damage caused by metabolically generated endogenous as well as external oxidants and oxidant-inducers. The cumulative oxidative DNA damage is considered the key factor in aging and senescence while the effectiveness of anti-aging agents is often assessed by their ability to reduce such damage. Oxidative DNA damage also preconditions cells to neoplastic transformation. Sensitive reporters of DNA damage, particularly the induction of DNA double-strand breaks (DSBs), are activation of ATM, through its phosphorylation on Ser 1981, and phosphorylation of histone H2AX on Ser 139; the phosphorylated form of H2AX has been named γH2AX. We review the observations that constitutive ATM activation (CAA) and H2AX phosphorylation (CHP) take place in normal cells as well in the cells of tumor lines untreated by exogenous genotoxic agents. We postulate that CAA and CHP, which have been measured by multiparameter cytometry in relation to the cell cycle phase, are triggered by oxidative DNA damage. This review also presents the findings on differences in CAA and CHP in various cell lines as well as on the effects of several agents and growth conditions that modulate the extent of these histone and ATM modifications. Specifically, described are effects of the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC), and the glutathione synthetase inhibitor buthionine sulfoximine (BSO) as well as suppression of cell metabolism by growth at higher cell density or in the presence of the glucose antimetabolite 2-deoxy-D-glucose. Collectively, the reviewed data indicate that multiparameter cytometric measurement of the level of CHP and/or CAA allows one to estimate the extent of ongoing oxidative DNA damage and to measure the DNA protective-effects of antioxidants or agents that reduce or amplify generation of endogenous ROS. Keywordsaging; senescence; DNA replication; DNA double-strand breaks; cell cycle; free radicals; reactive oxygen species (ROS); reactive oxygen intermediates (ROIs); anti-oxidants; oxidative stress DNA DAMAGE BY ENDOGENOUS OXIDANTSBeing continuously exposed to oxidants produced during metabolic activity and to external oxidants or oxidant-inducers, DNA within cells undergoes oxidative damage. Estimates of the extent of endogenous DNA damage vary widely. [1][2][3][4][5] 5 Recombinatorial repair (also known as template-assisted repair or homologous recombination repair) and nonhomologous DNA-end joining (NHEJ) are two major pathways for repair of DSBs. The NHEJ pathway is error-prone, often resulting in deletion of a few base pairs. 6,7 This leads to accumulation of DNA damage with each sequential cell cycle, which is considered to be the primary cause of cell aging and senescence. 4,8,9 The cumulative DNA damage also promotes development of preneoplastic changes. Many strategies aimed at slowing down the aging process or preventing cancer are based on protection of DNA from oxidative damage, primarily by scavenging the endogenous oxidants. While appr...

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“…There are two routes by which an increase could arise: more DSB DNA damage and/or a change in the repair of DNA damage. Unfortunately, methods to directly measure DNA damage in the form of DSBs are notoriously insensitive and while surrogate markers (modified or localized repair proteins) are available, they are difficult to accurately quantify (reviewed in Takahashi and Ohnishi, 2005). Furthermore, even with accurate quantification of DSBs, it would be unclear whether an increase in DSBs was the result of more intrinsic DNA damage or a failure to accurately repair normal levels of damage.…”

Section: Does the Ability To Repair Dna Damage Diminish With Age?mentioning

confidence: 99%

Does age influence loss of heterozygosity?

Carr

Gottschling

2008

Experimental Gerontology

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The striking correlation between advanced age and an increased incidence of cancer has led investigators to examine the influence of aging on genome maintenance.Because loss of heterozygosity (LOH) can lead to the inactivation of tumor suppressor genes, and thus carcinogenesis, understanding the affect of aging on this type of mutation event is particularly important. Several factors may affect the rate of LOH, including an increase in the amount of DNA damage, specifically double-strand breaks (DSB), and the ability to efficiently repair this damage via pathways that minimize the loss of genetic information. Because of experimental constraints, there is only suggestive evidence for a change in the rate of DNA damage as humans age. However, recent studies in model organisms find that there are increased rates of LOH with age, and that repair of DNA damage occurs via a different pathway in old cells versus young cells. We speculate that the age-dependent change in DNA repair may explain why there is increased LOH, and that the findings from these model organisms may extend to humans.

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Does γH2AX foci formation depend on the presence of DNA double strand breaks?

Cited by 206 publications

References 65 publications

Cytosolic accumulation of γH2AX is associated with tropomyosin-related kinase A-induced cell death in U2OS cells

Cytosolic accumulation of γH2AX is associated with tropomyosin-related kinase A-induced cell death in U2OS cells

Constitutive Histone H2AX Phosphorylation and ATM Activation, the Reporters of DNA Damage by Endogenous Oxidants

Does age influence loss of heterozygosity?

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