scholarly journals Kdm4b Histone Demethylase Is a DNA Damage Response Protein and Confers a Survival Advantage following γ-Irradiation

2013 ◽  
Vol 288 (29) ◽  
pp. 21376-21388 ◽  
Author(s):  
Leah C. Young ◽  
Darin W. McDonald ◽  
Michael J. Hendzel
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Early Time ◽  
Γ Irradiation ◽  
Aberrant Expression ◽  
Γh2ax Foci ◽  
Damage Response ◽  
Demethylase Activity ◽  
Differentiation And Proliferation ◽  
Tumor Types

DNA damage evokes a complex and highly coordinated DNA damage response (DDR) that is integral to the suppression of genomic instability. Double-strand breaks (DSBs) are considered the most deleterious form damage. Evidence suggests that trimethylation of histone H3 lysine 9 (H3K9me3) presents a barrier to DSB repair. Also, global levels of histone methylation are clinically predictive for several tumor types. Therefore, demethylation of H3K9 may be an important step in the repair of DSBs. The KDM4 subfamily of demethylases removes H3K9 tri- and dimethylation and contributes to the regulation of cellular differentiation and proliferation; mutation or aberrant expression of KDM4 proteins has been identified in several human tumors. We hypothesize that members of the KDM4 subfamily may be components of the DDR. We found that Kdm4b-enhanced GFP (EGFP) and KDM4D-EGFP were recruited rapidly to DNA damage induced by laser micro-irradiation. Focusing on the clinically relevant Kdm4b, we found that recruitment was dependent on poly(ADP-ribose) polymerase 1 activity as well as Kdm4b demethylase activity. The Kdm4 proteins did not measurably accumulate at γ-irradiation-induced γH2AX foci. Nevertheless, increased levels of Kdm4b were associated with decreased numbers of γH2AX foci 6 h after irradiation as well as increased cell survival. Finally, we found that levels of H3K9me2 and H3K9me3 were decreased at early time points after 2 gray of γ-irradiation. Taken together, these data demonstrate that Kdm4b is a DDR protein and that overexpression of Kdm4b may contribute to the failure of anti-cancer therapy that relies on the induction of DNA damage.

scholarly journals DNA Damage and DNA Damage Response in Chronic Myeloid Leukemia

2020 ◽  
Vol 21 (4) ◽  
pp. 1177 ◽  
Author(s):  
Popp ◽  
Kohl ◽  
Naumann ◽  
Flach ◽  
Brendel ◽  
...  
Keyword(s):  
Dna Damage ◽  
Chronic Myeloid Leukemia ◽  
Dna Damage Response ◽  
Myeloid Leukemia ◽  
Molecular Response ◽  
Blastic Transformation ◽  
Γh2ax Foci ◽  
Damage Response ◽  
Nhej Repair ◽  
Repair Mechanisms

DNA damage and alterations in the DNA damage response (DDR) are critical sources of genetic instability that might be involved in BCR-ABL1 kinase-mediated blastic transformation of chronic myeloid leukemia (CML). Here, increased DNA damage is detected by γH2AX foci analysis in peripheral blood mononuclear cells (PBMCs) of de novo untreated chronic phase (CP)-CML patients (n = 5; 2.5 γH2AX foci per PBMC ± 0.5) and blast phase (BP)-CML patients (n = 3; 4.4 γH2AX foci per PBMC ± 0.7) as well as CP-CML patients with loss of major molecular response (MMR) (n = 5; 1.8 γH2AX foci per PBMC ± 0.4) when compared to DNA damage in PBMC of healthy donors (n = 8; 1.0 γH2AX foci per PBMC ± 0.1) and CP-CML patients in deep molecular response or MMR (n = 26; 1.0 γH2AX foci per PBMC ± 0.1). Progressive activation of erroneous non-homologous end joining (NHEJ) repair mechanisms during blastic transformation in CML is indicated by abundant co-localization of γH2AX/53BP1 foci, while a decline of the DDR is suggested by defective expression of (p-)ATM and (p-)CHK2. In summary, our data provide evidence for the accumulation of DNA damage in the course of CML and suggest ongoing DNA damage, erroneous NHEJ repair mechanisms, and alterations in the DDR as critical mediators of blastic transformation in CML.

scholarly journals Targeting of histone methyltransferase DOT1L plays a dual role in chemosensitization of retinoblastoma cells and enhances the efficacy of chemotherapy

2021 ◽  
Vol 12 (12) ◽  
Author(s):  
Yu Mao ◽  
Yu Sun ◽  
Zhixuan Wu ◽  
Jingzhi Zheng ◽  
Jianing Zhang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Combined Therapy ◽  
Single Agent ◽  
Chemotherapeutic Agents ◽  
Dual Role ◽  
Aberrant Expression ◽  
Chromatin Regulators ◽  
Therapeutic Benefits ◽  
Damage Response

AbstractAberrant and exclusive expression of chromatin regulators in retinoblastoma (RB) in contrast to terminally differentiated normal retina presents a unique opportunity of selective targeting for RB. However, precise roles of these chromatin regulators in RB development and their potential as therapeutic targets have not been defined thoroughly. Here, we report that targeting of disruptor of telomeric silencing 1-like (DOT1L), a histone H3K79 methyltransferase, sensitizes RB cells to chemotherapeutic drugs by impairing the DNA damage response and thereby potentiating apoptosis while it is largely inefficacious as a single-agent therapy. Moreover, we identified high mobility group AT-hook 2 (HMGA2) as a novel DOT1L target gene in RB cells and found that its aberrant expression is dependent on DOT1L. As HMGA2 depletion reduced CHK1 phosphorylation during DNA damage response and augmented the drug sensitivity in RB cells, our results suggested that DOT1L targeting has a dual role in chemosensitization of RB cells by directly interfering with the immediate involvement of DOT1L in early DNA damage response upon genotoxic insults and also by downregulating the expression of HMGA2 as a rather late effect of DOT1L inhibition. Furthermore, we provide the first preclinical evidence demonstrating that combined therapy with a DOT1L inhibitor significantly improves the therapeutic efficacy of etoposide in murine orthotopic xenografts of RB by rendering the response to etoposide more potent and stable. Taken together, these results support the therapeutic benefits of DOT1L targeting in combination with other chemotherapeutic agents in RB, with mechanistic insights into how DOT1L targeting can improve the current chemotherapy in an RB cell-selective manner.

Modulation of DNA Damage Response by Samhd1 Determines Prognosis and Treatment Efficacy in Different Solid Tumor Types

2021 ◽  
Author(s):  
Eudald Felip ◽  
Lucia Gutierrez-Chamorro ◽  
Maica Gómez ◽  
Edurne Garcia-Vidal ◽  
Margarita Romeo ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Solid Tumor ◽  
Treatment Efficacy ◽  
Damage Response ◽  
Tumor Types

scholarly journals Development of a High-Content Screening Method for Chemicals Modulating DNA Damage Response

2011 ◽  
Vol 16 (2) ◽  
pp. 259-265 ◽  
Author(s):  
Sunshin Kim ◽  
Dong Hwa Jun ◽  
Hye Jin Kim ◽  
Kyung-Chae Jeong ◽  
Chang-Hun Lee
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Cellular Response ◽  
Large Scale ◽  
Screening Method ◽  
Measuring System ◽  
High Content Screening ◽  
Chemical Library ◽  
Γh2ax Foci ◽  
Damage Response

The cellular response to DNA damage is emerging as a promising target for cancer therapy. In the present study, the authors exploited the relationship between the level of the phosphorylated form of histone H2AX (γH2AX) and the extent of DNA damage and developed a quantitative, cell-based, high-content screening system for measuring the DNA damage response (DDR). In this system, the authors quantified the level of γH2AX by measuring DNA damage–induced γH2AX nuclear foci using an automated cell imager. They found that the total area of γH2AX foci per cell exhibited a good correlation with the concentration of DNA damage–inducing agents, including etoposide. The effects of 2 well-known inhibitors of DNA damage could be quantified using this system, suggesting the suitability of the γH2AX-foci quantification method for large-scale screening applications. This was confirmed by using this method to screen a chemical library; the resulting “hits” included compounds that inhibited early signaling events in DDR, as well those that inhibited subsequent DNA damage repair processes. Overall, this γH2AX foci-measuring system may be an effective screening method for identifying DNA damage response inhibitors that could eventually be used to develop novel anticancer drugs.

scholarly journals γH2AX Foci Increase Across the Spectrum from Myelodysplastic Syndromes to Acute Myeloid Leukemias and Co-Localize with 53BP1 in Specific Patterns in the Context of an Impaired DNA Damage Response

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5226-5226
Author(s):  
Henning D Popp ◽  
Susanne Brendel ◽  
Nicole Naumann ◽  
Thomas Henzler ◽  
Wolf-Karsten Hofmann ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dna Damage ◽  
Cell Lines ◽  
Dna Damage Response ◽  
Myelodysplastic Syndromes ◽  
Continuous Increase ◽  
Γh2ax Foci ◽  
Myeloid Leukemias ◽  
Damage Response ◽  
Acute Myeloid

Abstract Purpose: Increased DNA damage and alteration of the DNA damage response (DDR) are critical features of genetic instability presumably implicated in pathogenesis of myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). Materials and methods: We performed combined γH2AX/53BP1 immunofluorescent focus staining of DNA double-strand breaks (DSB) in MDS and AML cell lines, in CD34+ selected cells of normal and MDS bone marrow (including three cases of chronic myelomonocytic leukemias) and in blasts of AML bone marrow. In addition, we screened for activation of DDR by immunoblotting of p-ATM, p-ATR, p-CHK1, p-CHK2 and p-TP53. Results: Compared to γH2AX foci levels in normal bone marrow samples (0.18 focus per CD34+ ± 0.6), increased levels of γH2AX foci were detected in 1/1 MDS cell line (6.4 foci per cell ± 0.0), 6/6 AML cell lines (12.0 foci per cell ± 0.6), 12/12 MDS bone marrow samples (2.8 foci per CD34+ ± 0.7) as well as 12/12 AML bone marrow samples (6.0 foci per blast ± 0.6). γH2AX and 53BP1 co-localized in all tested samples forming diffuse, clustered and marginal patterns. DDR proteins were expressed heterogeneously suggesting impairment of DDR. Conclusions: Our results provide evidence for a continuous increase of constitutive DSB across the spectrum from MDS to AML in the context of an impaired DDR. γH2AX and 53BP1 co-localize in unique patterns in nuclei of MDS and AML presumably owing to a non-random spatial organization of the genome and foci formation implies promotion of ineffective nonhomologous end-joining repair mechanisms at sites of constitutive DSB. Disclosures No relevant conflicts of interest to declare.

scholarly journals Roles of GOLPH3, a PI(4)P binding protein, in the physiopathology of cancer

2020 ◽  
Author(s):  
Maria Grazia Giansanti ◽  
Roberto Piergentili ◽  
Angela Karimpour Ghahnavieh ◽  
Anna Frappaolo ◽  
Stefano Sechi
Keyword(s):  
Dna Damage ◽  
Plasma Membrane ◽  
Dna Damage Response ◽  
Membrane Trafficking ◽  
Poor Prognosis ◽  
Genomic Stability ◽  
Damage Response ◽  
Ribbon Structure ◽  
Phosphatidylinositol 4 ◽  
Tumor Types

Golgi phosphoprotein 3 (GOLPH3), a Phosphatidylinositol 4-Phosphate [PI(4)P] effector at the Golgi, is required for several intracellular functions, including Golgi ribbon structure maintenance, Golgi glycosylation and vesicle trafficking. It is amplified in several solid tumor types and its overexpression correlates with poor prognosis. GOLPH3 influences tumorigenesis through (i) regulation of Golgi-to-plasma membrane trafficking; (ii) turnover and glycosylation of cancer-relevant glycoproteins; (iii) influence on DNA damage response and maintenance of genomic stability.

scholarly journals UHRF1 is a genome caretaker that facilitates the DNA damage response to γ-irradiation

2010 ◽  
Vol 1 (1) ◽  
pp. 7 ◽  
Author(s):  
Helena Mistry ◽  
Laura Tamblyn ◽  
Hussein Butt ◽  
Daniel Sisgoreo ◽  
Aileen Gracias ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Γ Irradiation ◽  
A Genome ◽  
Damage Response

scholarly journals The histone demethylase LSD1/KDM1A promotes the DNA damage response

2013 ◽  
Vol 203 (3) ◽  
pp. 457-470 ◽  
Author(s):  
Nima Mosammaparast ◽  
Haeyoung Kim ◽  
Benoit Laurent ◽  
Yu Zhao ◽  
Hui Jun Lim ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Ubiquitin Ligase ◽  
Histone Demethylase ◽  
Dependent Manner ◽  
Γ Irradiation ◽  
Histone Demethylation ◽  
Direct Role ◽  
Damage Response ◽  
Histone Ubiquitylation

Histone demethylation is known to regulate transcription, but its role in other processes is largely unknown. We report a role for the histone demethylase LSD1/KDM1A in the DNA damage response (DDR). We show that LSD1 is recruited directly to sites of DNA damage. H3K4 dimethylation, a major substrate for LSD1, is reduced at sites of DNA damage in an LSD1-dependent manner. The E3 ubiquitin ligase RNF168 physically interacts with LSD1 and we find this interaction to be important for LSD1 recruitment to DNA damage sites. Although loss of LSD1 did not affect the initial formation of pH2A.X foci, 53BP1 and BRCA1 complex recruitment were reduced upon LSD1 knockdown. Mechanistically, this was likely a result of compromised histone ubiquitylation preferentially in late S/G2. Consistent with a role in the DDR, knockdown of LSD1 resulted in moderate hypersensitivity to γ-irradiation and increased homologous recombination. Our findings uncover a direct role for LSD1 in the DDR and place LSD1 downstream of RNF168 in the DDR pathway.

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