DNA Damage Response and Inflammatory Signaling Limit the MLL-ENL-Induced Leukemogenesis In Vivo

Abstract Despite the rapid improvements in unveiling the importance of lncRNAs in all aspects of cancer biology, there is still a void in mechanistic understanding of their role in the DNA damage response. Here we explored the potential role of the oncogenic lncRNA SCAT7 (ELF3-AS1) in the maintenance of genome integrity. We show that SCAT7 is upregulated in response to DNA-damaging drugs like cisplatin and camptothecin, where SCAT7 expression is required to promote cell survival. SCAT7 silencing leads to decreased proliferation of cisplatin-resistant cells in vitro and in vivo through interfering with cell cycle checkpoints and DNA repair molecular pathways. SCAT7 regulates ATR signaling, promoting homologous recombination. Importantly, SCAT7 also takes part in proteasome-mediated topoisomerase I (TOP1) degradation, and its depletion causes an accumulation of TOP1–cc structures responsible for the high levels of intrinsic DNA damage. Thus, our data demonstrate that SCAT7 is an important constituent of the DNA damage response pathway and serves as a potential therapeutic target for hard-to-treat drug resistant cancers.

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PAICS contributes to gastric carcinogenesis and participates in DNA damage response by interacting with histone deacetylase 1/2

Cell Death and Disease ◽

10.1038/s41419-020-2708-5 ◽

2020 ◽

Vol 11 (7) ◽

Author(s):

Nan Huang ◽

Chang Xu ◽

Liang Deng ◽

Xue Li ◽

Zhixuan Bian ◽

...

Keyword(s):

Dna Damage ◽

Histone Deacetylase ◽

Dna Damage Response ◽

De Novo ◽

Dna Damage Repair ◽

Histone Deacetylase 1 ◽

Damage Repair ◽

Damage Response

AbstractPhosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.

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Slx4 Regulates DNA Damage Checkpoint-dependent Phosphorylation of the BRCT Domain Protein Rtt107/Esc4

Molecular Biology of the Cell ◽

10.1091/mbc.e05-08-0785 ◽

2006 ◽

Vol 17 (1) ◽

pp. 539-548 ◽

Cited By ~ 59

Author(s):

Tania M. Roberts ◽

Michael S. Kobor ◽

Suzanne A. Bastin-Shanower ◽

Miki Ii ◽

Sonja A. Horte ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Dna Damage Checkpoint ◽

Checkpoint Activation ◽

Alkylation Damage ◽

Binding Partner ◽

Replication Restart ◽

Damage Response ◽

Domain Protein

RTT107 (ESC4, YHR154W) encodes a BRCA1 C-terminal-domain protein that is important for recovery from DNA damage during S phase. Rtt107 is a substrate of the checkpoint protein kinase Mec1, although the mechanism by which Rtt107 is targeted by Mec1 after checkpoint activation is currently unclear. Slx4, a component of the Slx1-Slx4 structure-specific nuclease, formed a complex with Rtt107. Deletion of SLX4 conferred many of the same DNA-repair defects observed in rtt107Δ, including DNA damage sensitivity, prolonged DNA damage checkpoint activation, and increased spontaneous DNA damage. These phenotypes were not shared by the Slx4 binding partner Slx1, suggesting that the functions of the Slx4 and Slx1 proteins in the DNA damage response were not identical. Of particular interest, Slx4, but not Slx1, was required for phosphorylation of Rtt107 by Mec1 in vivo, indicating that Slx4 was a mediator of DNA damage-dependent phosphorylation of the checkpoint effector Rtt107. We propose that Slx4 has roles in the DNA damage response that are distinct from the function of Slx1-Slx4 in maintaining rDNA structure and that Slx4-dependent phosphorylation of Rtt107 by Mec1 is critical for replication restart after alkylation damage.

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Dephosphorylation of the C-terminal Tyrosyl Residue of the DNA Damage-related Histone H2A.X Is Mediated by the Protein Phosphatase Eyes Absent

Journal of Biological Chemistry ◽

10.1074/jbc.c900032200 ◽

2009 ◽

Vol 284 (24) ◽

pp. 16066-16070 ◽

Cited By ~ 88

Author(s):

Navasona Krishnan ◽

Dae Gwin Jeong ◽

Suk-Kyeong Jung ◽

Seong Eon Ryu ◽

Andrew Xiao ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Mammalian Cells ◽

Protein Tyrosine Phosphatases ◽

Histone H2a ◽

Eyes Absent ◽

Damage Repair ◽

Damage Response

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.X has been shown to be an important regulator of the DNA damage response by controlling the formation of γH2A.X foci, which are platforms for recruiting molecules involved in DNA damage repair and signaling. In this work, we present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. Suppression of eya3 by RNA interference resulted in elevated basal phosphorylation and inhibited DNA damage-induced dephosphorylation of Tyr-142 of H2A.X in vivo. This study provides the first indication of a physiological substrate for the EYA phosphatases and suggests a novel role for these enzymes in regulation of the DNA damage response.

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The Circadian Gene Period2 Plays an Important Role in Tumor Suppression and DNA-Damage Response In Vivo

Cell ◽

10.1016/s0092-8674(02)01223-0 ◽

2002 ◽

Vol 111 (7) ◽

pp. 1055 ◽

Cited By ~ 15

Author(s):

Loning Fu ◽

Helene Pelicano ◽

Jinsong Liu ◽

Peng Huang ◽

Cheng Chi Lee

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Tumor Suppression ◽

Circadian Gene ◽

Damage Response

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Werner Protein Protects Nonproliferating Cells from Oxidative DNA Damage

Molecular and Cellular Biology ◽

10.1128/mcb.25.23.10492-10506.2005 ◽

2005 ◽

Vol 25 (23) ◽

pp. 10492-10506 ◽

Cited By ~ 62

Author(s):

Anna M. Szekely ◽

Franziska Bleichert ◽

Astrid Nümann ◽

Stephen Van Komen ◽

Elisabeth Manasanch ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Oxidative Dna Damage ◽

Werner Syndrome ◽

Human Fibroblasts ◽

Telomere Maintenance ◽

Telomere Binding Protein ◽

Damage Response ◽

Dividing Cells

ABSTRACT Werner syndrome, caused by mutations of the WRN gene, mimics many changes of normal aging. Although roles for WRN protein in DNA replication, recombination, and telomere maintenance have been suggested, the pathology of rapidly dividing cells is not a feature of Werner syndrome. To identify cellular events that are specifically vulnerable to WRN deficiency, we used RNA interference (RNAi) to knockdown WRN or BLM (the RecQ helicase mutated in Bloom syndrome) expression in primary human fibroblasts. Withdrawal of WRN or BLM produced accelerated cellular senescence phenotype and DNA damage response in normal fibroblasts, as evidenced by induction of γH2AX and 53BP1 nuclear foci. After WRN depletion, the induction of these foci was seen most prominently in nondividing cells. Growth in physiological (3%) oxygen or in the presence of an antioxidant prevented the development of the DNA damage foci in WRN-depleted cells, whereas acute oxidative stress led to inefficient repair of the lesions. Furthermore, WRN RNAi-induced DNA damage was suppressed by overexpression of the telomere-binding protein TRF2. These conditions, however, did not prevent the DNA damage response in BLM-ablated cells, suggesting a distinct role for WRN in DNA homeostasis in vivo. Thus, manifestations of Werner syndrome may reflect an impaired ability of slowly dividing cells to limit oxidative DNA damage.

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PML Colocalizes with and Stabilizes the DNA Damage Response Protein TopBP1

Molecular and Cellular Biology ◽

10.1128/mcb.23.12.4247-4256.2003 ◽

2003 ◽

Vol 23 (12) ◽

pp. 4247-4256 ◽

Cited By ~ 74

Author(s):

Zhi-Xiang Xu ◽

Anna Timanova-Atanasova ◽

Rui-Xun Zhao ◽

Kun-Sang Chang

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Genome Stability ◽

Growth Regulation ◽

Suppressor Gene ◽

Nuclear Body ◽

Promyelocytic Leukemia ◽

Multifunctional Protein ◽

Damage Response

ABSTRACT The PML tumor suppressor gene is consistently disrupted by t(15;17) in patients with acute promyelocytic leukemia. Promyelocytic leukemia protein (PML) is a multifunctional protein that plays essential roles in cell growth regulation, apoptosis, transcriptional regulation, and genome stability. Our study here shows that PML colocalizes and associates in vivo with the DNA damage response protein TopBP1 in response to ionizing radiation (IR). Both PML and TopBP1 colocalized with the IR-induced bromodeoxyuridine single-stranded DNA foci. PML and TopBP1 also colocalized with Rad50, Brca1, ATM, Rad9, and BLM. IR and interferon (IFN) coinduce the expression levels of both TopBP1 and PML. In PML-deficient NB4 cells, TopBP1 was unable to form IR-induced foci. All-trans-retinoic acid induced reorganization of the PML nuclear body (NB) and reappearance of the IR-induced TopBP1 foci. Inhibition of PML expression by siRNA is associated with a significant decreased in TopBP1 expression. Furthermore, PML-deficient cells express a low level of TopBP1, and its expression cannot be induced by IR or IFN. Adenovirus-mediated overexpression of PML in PML−/− mouse embryo fibroblasts substantially increased TopBP1 expression, which colocalized with the PML NBs. These studies demonstrated a mechanism of PML-dependent expression of TopBP1. PML overexpression induced TopBP1 protein but not the mRNA expression. Pulse-chase labeling analysis demonstrated that PML overexpression stabilized the TopBP1 protein, suggesting that PML plays a role in regulating the stability of TopBP1 in response to IR. Together, our findings demonstrate that PML regulates TopBP1 functions by association and stabilization of the protein in response to IR-induced DNA damage.

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Regulation of Rtt107 Recruitment to Stalled DNA Replication Forks by the Cullin Rtt101 and the Rtt109 Acetyltransferase

Molecular Biology of the Cell ◽

10.1091/mbc.e07-09-0961 ◽

2008 ◽

Vol 19 (1) ◽

pp. 171-180 ◽

Cited By ~ 45

Author(s):

Tania M. Roberts ◽

Iram Waris Zaidi ◽

Jessica A. Vaisica ◽

Matthias Peter ◽

Grant W. Brown

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Replication Forks ◽

Chromatin Binding ◽

Direct Role ◽

Repair Enzymes ◽

Damage Response ◽

Stalled Replication Forks

RTT107 (ESC4, YHR154W) encodes a BRCA1 C-terminal domain protein that is important for recovery from DNA damage during S phase. Rtt107 is a substrate of the checkpoint kinase Mec1, and it forms complexes with DNA repair enzymes, including the nuclease subunit Slx4, but the role of Rtt107 in the DNA damage response remains unclear. We find that Rtt107 interacts with chromatin when cells are treated with compounds that cause replication forks to arrest. This damage-dependent chromatin binding requires the acetyltransferase Rtt109, but it does not require acetylation of the known Rtt109 target, histone H3-K56. Chromatin binding of Rtt107 also requires the cullin Rtt101, which seems to play a direct role in Rtt107 recruitment, because the two proteins are found in complex with each other. Finally, we provide evidence that Rtt107 is bound at or near stalled replication forks in vivo. Together, these results indicate that Rtt109, Rtt101, and Rtt107, which genetic evidence suggests are functionally related, form a DNA damage response pathway that recruits Rtt107 complexes to damaged or stalled replication forks.

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The Methyltransferase Set7/9 (Setd7) Is Dispensable for the p53-Mediated DNA Damage Response In Vivo

Molecular Cell ◽

10.1016/j.molcel.2011.08.007 ◽

2011 ◽

Vol 43 (4) ◽

pp. 681-688 ◽

Cited By ~ 56

Author(s):

Stefano Campaner ◽

Fabio Spreafico ◽

Thomas Burgold ◽

Mirko Doni ◽

Umberto Rosato ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Damage Response

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DNA Damage-Response Pathway in Lymphoma Determines Interactions with Macrophages By Altered PD-L1 Expression and Exosome Formation

Blood ◽

10.1182/blood-2018-99-120264 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 275-275

Author(s):

Daniela Vorholt ◽

Elena Izquierdo-Alvarez ◽

Benedict Sackey ◽

Jan Schmitz ◽

Nadine Nickel ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Research Funding ◽

Therapeutic Response ◽

Wild Type ◽

Lymphoma Cells ◽

Damage Response ◽

Dna Damage Response Pathway ◽

Support Research

Abstract The tumor microenvironment is characterized by multiple interactions of transformed malignant cells with non-transformed stroma or immune cells. Particularly macrophages play a pivotal role in this network determining disease progression and therapeutic response. In previous work we could show that macrophages are an essential mediator of therapeutic response in the synergistic response to the administration of the chemoimmunotherapy. The combination treatment strongly increases tumor clearance by repolarization of tumor-associated macrophages from a suppressive to an activated phenotypic state. Here, se analyzed the functional implications of the DNA damage response pathway for the generation of the ASAP and synergy in chemoimmunotherapy. We attempted to disrupt DNA damage response pathway in lymphoma cells generated from the hMB humanized Double-Hit-Lymphoma model by knock-down of key elements like ATM, DNA-PK or p53. We could prevent the formation of the stimulatory cytokine release effect on macrophage phagocytic capacity. Here, p53 status displays a key regulatory role on macrophage mediated malignant cell depletion. TP53 activation via Nutlin-3A treatment of lymphoma cell enhances ADCP in in p53 wild-type cells, while not displaying enhancement in p53-deficient lymphoma cells. Addressing the treatment in vivo using the hMB model for modeling of Double-Hit Lymphoma bearing mice we could demonstrate diminished ASAP and ADCP for p53-deficient lymphoma treated with cyclophosphamide in vivo. Using primary human CLL patient cells comparing both wild-type and p53-deficient status, the p53-deficient CLL cells failed to induce the stimulatory, cytokine-mediated effect on macrophage phagocytosis in response to combination treatment as seen with the p53 proficient CLL cells. Using a CLL mouse model by treating Eµ-TCL1/p53wt/wt as well as Eµ-TCL1p53-/- mice we could show that low-dose cyclophosphamide treated Eµ-TCL1p53-/- mice failed to induce an antibody mediated stimulatory effect on macrophage phagocytosis capacity as seen with Eµ-TCL1/p53wt/wt mice. A similar effect was seen for primary multiple myeloma cells in response to daratumumab displaying significantly less ADCP of p53-deficient multiple myeloma cells. As for the mechanism of p53-defined interaction within the tumor microenvironment we subjected p53-wild-type and p53-deficient lymphoma cells for proteomic analysis. Here we could identify a significantly deregulated protein expression profile for exosome release in p53 deficient lymphoma cells. Verifying this finding by assessing size and frequency exosomes released by respective cell populations we reveal profound changes induced by p53 loss. Furthermore we could identify up-regulation of PD-L1 in p53-deficient cells. Blocking this checkpoint in the ADCP assay could significantly restore phagocytic capacity of macrophages and overall therapeutic response. In this work, we indicate that p53 functional status determines phagocytic function and therapeutic response to monoclonal antibodies. We can verify this finding in independent models in vitro and in vivo as in primary CLL and myeloma patient cells. We furthermore identify altered exosome profiles and checkpoint inhibitor expression in lymphoma cells as underlying mechanism of macrophage modulation. Finally our ongoing research offers possibility to reveal and tailor new combinatorial treatment approaches for chemo-refractory patients. Disclosures Wendtner: Genetech: Consultancy, Honoraria, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: travel support, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: travel support, Research Funding; Abbvie: Consultancy, Honoraria, Other: travel support, Research Funding; MorphoSys: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; Roche: Consultancy, Honoraria, Other: travel support, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding. Hallek:Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding. Pallasch:Gilead: Research Funding.

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