Spontaneously immortalized cell lines obtained from adult Atm null mice retain sensitivity to ionizing radiation and exhibit a mutational pattern suggestive of oxidative stress

BackgroundThe Fanconi anemia (FA) pathway is a multigene DNA damage response network implicated in the repair of DNA lesions that arise during replication or after exogenous DNA damage. The FA pathway displays synthetic lethal relationship with certain DNA repair genes such as ATM (Ataxia Telangectasia Mutated) that are frequently mutated in tumors. Thus, inhibition of FANCD2 monoubiquitylation (FANCD2-Ub), a key step in the FA pathway, might target tumor cells defective in ATM through synthetic lethal interaction. Curcumin was previously identified as a weak inhibitor of FANCD2-Ub. The aim of this study is to identify derivatives of curcumin with better activity and specificity.ResultsUsing a replication-free assay in Xenopus extracts, we screened monoketone analogs of curcumin for inhibition of FANCD2-Ub and identified analog EF24 as a strong inhibitor. Mechanistic studies suggest that EF24 targets the FA pathway through inhibition of the NF-kB pathway kinase IKK. In HeLa cells, nanomolar concentrations of EF24 inhibited hydroxyurea (HU)-induced FANCD2-Ub and foci in a cell-cycle independent manner. Survival assays revealed that EF24 specifically sensitizes FA-competent cells to the DNA crosslinking agent mitomycin C (MMC). In addition, in contrast with curcumin, ATM-deficient cells are twofold more sensitive to EF24 than matched wild-type cells, consistent with a synthetic lethal effect between FA pathway inhibition and ATM deficiency. An independent screen identified 4H-TTD, a compound structurally related to EF24 that displays similar activity in egg extracts and in cells.ConclusionsThese results suggest that monoketone analogs of curcumin are potent inhibitors of the FA pathway and constitute a promising new class of targeted anticancer compounds.

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“…ATM-deficient and ATM-proficient kidney cells from congenic adult mice (309 ATM KO and 334 ATM WT ) [51] were grown in the same medium.…”

Section: Methodsmentioning

confidence: 99%

Monoketone analogs of curcumin, a new class of Fanconi anemia pathway inhibitors

et al. 2009

Self Cite

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“…(13,79) ATM has been shown to be directly involved in oxidative stress-related mechanisms that are relevant to the function of ATM and to the pathogenesis of this disorder. (3,(80)(81)(82)(83)(84) Interestingly, there are Trx abnormalities in cerebella of Atm À/À mice. (82) Coupled with the observation that Trx ameliorates the cytotoxicity of MMC, (11) it is possible that the association of ATM with FANCD2 could modulate the redox state of FA cells through the modulation of Trx levels.…”

Section: Fancd1 and Fancd2 Interactions: Possible Links?mentioning

confidence: 98%

“…FANCA Phosphorylated by Akt kinase at Ser1149 (68) Akt kinase Active in redox-dependent cell signaling (69,70) FANCD1, BRCA2 and FANCD2 Interacting with ATM, BRCA1, and RAD51 (71)(72)(73)(74)(77)(78)(79) Involved in the repair of oxidative DNA damage (75,76) ATM Involved in oxidative stress-related mechanisms (3,(80)(81)(82)(83)(84) Review articles stration that FANCC complementation of FA-C cells prevents the accumulation of oxidative DNA damage. (61) An association was also demonstrated between FANCC and glutathione Stransferase (GSTP1).…”

Section: Hexavalent Chromiummentioning

confidence: 99%

Fanconi anaemia proteins: Major roles in cell protection against oxidative damage

Pagano¹,

Youssoufian

2003

BioEssays

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Fanconi anaemia (FA) is a cancer-prone genetic disorder that is characterised by cytogenetic instability and redox abnormalities. Although rare subtypes of FA (B, D1 and D2) have been implicated in DNA repair through links with BRCA1 and BRCA2, such a role has yet to be demonstrated for gene products of the common subtypes. Instead, these products have been strongly implicated in xenobiotic metabolism and redox homeostasis through interactions of FANCC with cytochrome P-450 reductase and with glutathione S-transferase, and of FANCG with cytochrome P-450 2E1, as well as redox-dependent signalling through an interaction between FANCA and Akt kinase. We hypothesise that FA proteins act directly (via FANCC and FANCG) and indirectly (via FANCA, BRCA2 and FANCD2) with the machinery of cellular defence to modulate oxidative stress. The latter interactions may co-ordinate the link between the response to DNA damage and oxidative stress parameters (3, 6-12).

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“…Primary fibroblast cells lines (GM5823, HFF, and BJ) and the establishment of their hTERT-derived counterparts were described previously (48). Mouse fibroblasts 435 (with ATM) and 743 (without ATM) cells have been described previously (10).…”

Section: Methodsmentioning

confidence: 99%

The Mammalian Ortholog of Drosophila MOF That Acetylates Histone H4 Lysine 16 Is Essential for Embryogenesis and Oncogenesis

Gupta

Guerin-Peyrou

Sharma

et al. 2008

Molecular and Cellular Biology

198

251

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The mammalian ortholog of the Drosophila MOF (males absent on the first) gene product is a histone H4 lysine 16-specific acetyltransferase. Recent studies have shown that depletion of human MOF (hMOF) in human cell lines leads to genomic instability, spontaneous chromosomal aberrations, cell cycle defects, altered nuclear morphology, reduced transcription of certain genes, and defective DNA damage response to ionizing radiation (IR). Here we show that MOF plays an essential role in mammals during embryogenesis and oncogenesis. Ablation of the mouse Mof gene (mMof) by gene targeting resulted in early embryonic lethality and cell death. Lethality correlated with the loss of H4 lysine 16 acetylation (H4K16ac) and could not be rescued by concomitant inactivation of ATM or p53. In comparison to primary cells or normal tissue, all immortalized human normal and tumor cell lines and primary tumors demonstrated similar or elevated hMOF and H4K16ac levels. Accordingly, MOF overexpression correlated with increased cellular proliferation, oncogenic transformation, and tumor growth. Thus, these data reveal that the acetylation of histone H4 at K16 by MOF is an epigenetic signature of cellular proliferation common to both embryogenesis and oncogenesis and that MOF is an essential factor for embryogenesis and oncogenesis.MOF belongs to the MYST family of acetyltransferases, which have been associated with acute myeloid leukemia (MOZ), transcriptional silencing in Saccharomyces cerevisiae (SAS2 and YBF2/SAS3), interactions with human immunodeficiency virus Tat in humans (TIP60), and dosage compensation in Drosophila melanogaster (MOF), in addition to their role in DNA damage repair (2,4,12,13,17,18,43,44,46). Akhtar and Becker (1) demonstrated that Drosophila MOF is a histone acetyltransferase that acetylates chromatin specifically at histone H4 lysine 16 (H4K16). Depletion of human MOF (hMOF) in human cells results in the loss of acetylation at lysine 16 of histone H4 (6, 12, 41, 45, 46), strongly arguing that the highly conserved MOF protein may be the major histone acetyltransferase, which acetylates histone H4 at K16.Acetylation at K16 of histone H4 (H4K16ac) is a prevalent and reversible posttranslational chromatin modification in eukaryotes, and recent studies have highlighted its significance. Shogren-Knaak and coworkers have found that a single histone H4K16ac modification modulates both higher-order chromatin structure and functional interactions between a nonhistone protein and the chromatin fiber (39). Shia and coworkers have demonstrated that the presence of H4K16ac and H2A.Z synergistically prevent the ectopic propagation of heterochromatin in the subtelomeric regions of yeast (36). Furthermore, it is well understood that H4K16ac disrupts higher-order chromatin structure, changes the functional interactions between chromatin-associated proteins (39), and serves as a switch for altering chromatin from a repressive to a transcriptionally active state in yeast and humans (36). Interestingly, Dou and coworkers reported...

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Spontaneously immortalized cell lines obtained from adult Atm null mice retain sensitivity to ionizing radiation and exhibit a mutational pattern suggestive of oxidative stress

Cited by 21 publications

References 27 publications

Monoketone analogs of curcumin, a new class of Fanconi anemia pathway inhibitors

Monoketone analogs of curcumin, a new class of Fanconi anemia pathway inhibitors

Fanconi anaemia proteins: Major roles in cell protection against oxidative damage

The Mammalian Ortholog of Drosophila MOF That Acetylates Histone H4 Lysine 16 Is Essential for Embryogenesis and Oncogenesis

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