Corrupting the DNA damage response: a critical role for Rad52 in tumor cell survival

The nuclear factor kappa B (NF-κB) pathway is known to integrate signaling associated with very diverse intra- and extracellular stressors including virus infections, and triggers a powerful (pro-inflammatory) response through the expression of NF-κB-regulated genes. Typically, the NF-κB pathway collects and transduces threatening signals at the cell surface or in the cytoplasm leading to nuclear import of activated NF-κB transcription factors. In the current work, we demonstrate that the swine alphaherpesvirus pseudorabies virus (PRV) induces a peculiar mode of NF-κB activation known as “inside-out” NF-κB activation. We show that PRV triggers the DNA damage response (DDR) and that this DDR response drives NF-κB activation since inhibition of the nuclear ataxia telangiectasia-mutated (ATM) kinase, a chief controller of DDR, abolished PRV-induced NF-κB activation. Initiation of the DDR-NF-κB signaling axis requires viral protein synthesis but occurs before active viral genome replication. In addition, the initiation of the DDR-NF-κB signaling axis is followed by a virus-induced complete shutoff of NF-κB-dependent gene expression that depends on viral DNA replication. In summary, the results presented in this study reveal that PRV infection triggers a non-canonical DDR-NF-κB activation signaling axis and that the virus actively inhibits the (potentially antiviral) consequences of this pathway, by inhibiting NF-κB-dependent gene expression. IMPORTANCE: The NF-κB signaling pathway plays a critical role in coordination of innate immune responses that are of vital importance in the control of infections. The current report generates new insights in the interaction of the alphaherpesvirus pseudorabies virus (PRV) with the NF-κB pathway, as they reveal that (i) PRV infection leads to NF-κB activation via a peculiar “inside-out’ nucleus-to-cytoplasm signal that is triggered via the DNA damage response (DDR), (ii) the DDR-NF-κB signaling axis requires expression of viral proteins but is initiated before active PRV replication, and (iii) late viral factor(s) allow PRV to actively and efficiently inhibit NF-κB-dependent (pro-inflammatory) gene expression. These data suggest that activation of the DDR-NF-κB during PRV infection is host-driven and that its potential antiviral consequences are actively inhibited by the virus.

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Cisplatin-Induced DNA Damage Activates Replication Checkpoint Signaling Components that Differentially Affect Tumor Cell Survival

Molecular Pharmacology ◽

10.1124/mol.109.055178 ◽

2009 ◽

Vol 76 (1) ◽

pp. 208-214 ◽

Cited By ~ 79

Author(s):

Jill M. Wagner ◽

Larry M. Karnitz

Keyword(s):

Dna Damage ◽

Tumor Cell ◽

Cell Survival ◽

Replication Checkpoint ◽

Checkpoint Signaling ◽

Tumor Cell Survival ◽

Signaling Components

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Down-regulation of Wild-type p53-induced Phosphatase 1 (Wip1) Plays a Critical Role in Regulating Several p53-dependent Functions in Premature Senescent Tumor Cells

Journal of Biological Chemistry ◽

10.1074/jbc.m112.435149 ◽

2013 ◽

Vol 288 (23) ◽

pp. 16212-16224 ◽

Cited By ~ 16

Author(s):

Elvira Crescenzi ◽

Zelinda Raia ◽

Francesco Pacifico ◽

Stefano Mellone ◽

Fortunato Moscato ◽

...

Keyword(s):

Dna Damage ◽

Tumor Cells ◽

Dna Damage Response ◽

Critical Role ◽

Wild Type ◽

Down Regulation ◽

Senescent Phenotype ◽

Response To Chemotherapy ◽

Damage Response ◽

Wild Type P53

Premature or drug-induced senescence is a major cellular response to chemotherapy in solid tumors. The senescent phenotype develops slowly and is associated with chronic DNA damage response. We found that expression of wild-type p53-induced phosphatase 1 (Wip1) is markedly down-regulated during persistent DNA damage and after drug release during the acquisition of the senescent phenotype in carcinoma cells. We demonstrate that down-regulation of Wip1 is required for maintenance of permanent G2 arrest. In fact, we show that forced expression of Wip1 in premature senescent tumor cells induces inappropriate re-initiation of mitosis, uncontrolled polyploid progression, and cell death by mitotic failure. Most of the effects of Wip1 may be attributed to its ability to dephosphorylate p53 at Ser15 and to inhibit DNA damage response. However, we also uncover a regulatory pathway whereby suppression of p53 Ser15 phosphorylation is associated with enhanced phosphorylation at Ser46, increased p53 protein levels, and induction of Noxa expression. On the whole, our data indicate that down-regulation of Wip1 expression during premature senescence plays a pivotal role in regulating several p53-dependent aspects of the senescent phenotype.

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ATM regulates a DNA damage response posttranscriptional RNA operon in lymphocytes

Blood ◽

10.1182/blood-2010-09-310987 ◽

2011 ◽

Vol 117 (8) ◽

pp. 2441-2450 ◽

Cited By ~ 27

Author(s):

Krystyna Mazan-Mamczarz ◽

Patrick R. Hagner ◽

Yongqing Zhang ◽

Bojie Dai ◽

Elin Lehrmann ◽

...

Keyword(s):

Gene Expression ◽

Dna Damage ◽

Dna Damage Response ◽

Ataxia Telangiectasia ◽

Rna Binding ◽

Critical Role ◽

Cell Cycle Checkpoints ◽

Dependent Manner ◽

Damage Response ◽

Multiple Cell

Abstract Maintenance of genomic stability depends on the DNA damage response, a biologic barrier in early stages of cancer development. Failure of this response results in genomic instability and high predisposition toward lymphoma, as seen in patients with ataxia-telangiectasia mutated (ATM) dysfunction. ATM activates multiple cell-cycle checkpoints and DNA repair after DNA damage, but its influence on posttranscriptional gene expression has not been examined on a global level. We show that ionizing radiation modulates the dynamic association of the RNA-binding protein HuR with target mRNAs in an ATM-dependent manner, potentially coordinating the genotoxic response as an RNA operon. Pharmacologic ATM inhibition and use of ATM-null cells revealed a critical role for ATM in this process. Numerous mRNAs encoding cancer-related proteins were differentially associated with HuR depending on the functional state of ATM, in turn affecting expression of encoded proteins. The findings presented here reveal a previously unidentified role of ATM in controlling gene expression posttranscriptionally. Dysregulation of this DNA damage response RNA operon is probably relevant to lymphoma development in ataxia-telangiectasia persons. These novel RNA regulatory modules and genetic networks provide critical insight into the function of ATM in oncogenesis.

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Prolonged mitotic arrest induces a caspase-dependent DNA damage response at telomeres that determines cell survival

Scientific Reports ◽

10.1038/srep26766 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 20

Author(s):

Karolina O. Hain ◽

Didier J. Colin ◽

Shubhra Rastogi ◽

Lindsey A. Allan ◽

Paul R. Clarke

Keyword(s):

Dna Damage ◽

Cell Survival ◽

Dna Damage Response ◽

Mitotic Arrest ◽

Damage Response

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624 POSTER Rapid induction of telomeric DNA damage response and reduction of clonogenic tumor cell growth by the telomere targeting agent RHPS4

European Journal of Cancer Supplements ◽

10.1016/s1359-6349(06)70629-2 ◽

2006 ◽

Vol 4 (12) ◽

pp. 188

Author(s):

P. Phatak ◽

M.F.G. Stevens ◽

A.M. Burger

Keyword(s):

Dna Damage ◽

Cell Growth ◽

Tumor Cell ◽

Dna Damage Response ◽

Tumor Cell Growth ◽

Telomeric Dna ◽

Rapid Induction ◽

Clonogenic Tumor Cell ◽

Damage Response

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VRK1 Depletion Facilitates the Synthetic Lethality of Temozolomide and Olaparib in Glioblastoma Cells

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.683038 ◽

2021 ◽

Vol 9 ◽

Author(s):

Elena Navarro-Carrasco ◽

Pedro A. Lazo

Keyword(s):

Dna Damage ◽

Cell Death ◽

Tumor Cell ◽

Dna Damage Response ◽

Synthetic Lethality ◽

Glioblastoma Cell ◽

Glioblastoma Cells ◽

Tumor Cell Death ◽

Damage Response ◽

Parp 1

BackgroundGlioblastomas treated with temozolomide frequently develop resistance to pharmacological treatments. Therefore, there is a need to find alternative drug targets to reduce treatment resistance based on tumor dependencies. A possibility is to target simultaneously two proteins from different DNA-damage repair pathways to facilitate tumor cell death. Therefore, we tested whether targeting the human chromatin kinase VRK1 by RNA interference can identify this protein as a novel molecular target to reduce the dependence on temozolomide in combination with olaparib, based on synthetic lethality.Materials and MethodsDepletion of VRK1, an enzyme that regulates chromatin dynamic reorganization and facilitates resistance to DNA damage, was performed in glioblastoma cells treated with temozolomide, an alkylating agent used for GBM treatment; and olaparib, an inhibitor of PARP-1, used as sensitizer. Two genetically different human glioblastoma cell lines, LN-18 and LN-229, were used for these experiments. The effect on the DNA-damage response was followed by determination of sequential steps in this process: H4K16ac, γH2AX, H4K20me2, and 53BP1.ResultsThe combination of temozolomide and olaparib increased DNA damage detected by labeling free DNA ends, and chromatin relaxation detected by H4K16ac. The combination of both drugs, at lower doses, resulted in an increase in the DNA damage response detected by the formation of γH2AX and 53BP1 foci. VRK1 depletion did not prevent the generation of DNA damage in TUNEL assays, but significantly impaired the DNA damage response induced by temozolomide and olaparib, and mediated by γH2AX, H4K20me2, and 53BP1. The combination of these drugs in VRK1 depleted cells resulted in an increase of glioblastoma cell death detected by annexin V and the processing of PARP-1 and caspase-3.ConclusionDepletion of the chromatin kinase VRK1 promotes tumor cell death at lower doses of a combination of temozolomide and olaparib treatments, and can be a novel alternative target for therapies based on synthetic lethality.

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