scholarly journals Mitotic progression following DNA damage enables pattern recognition within micronuclei

2017 ◽  
Author(s):  
Shane M Harding ◽  
Joseph L Benci ◽  
Jerome Irianto ◽  
Dennis E Discher ◽  
Andy J Minn ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Pattern Recognition ◽  
Dna Damage ◽  
Immune Checkpoint ◽  
Cell Cycle Progression ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Dna Double Strand Breaks ◽  
Strand Breaks

Inflammatory gene expression following genotoxic cancer therapy is well documented, yet the events underlying its induction remain poorly understood. Inflammatory cytokines modify the tumor microenvironment by recruiting immune cells and are critical for both local and systemic (abscopal) tumor responses to radiotherapy1. An enigmatic feature of this phenomenon is its delayed onset (days), in contrast to the acute DNA damage responses that occur in minutes to hours. Such dichotomous kinetics implicate additional rate limiting steps that are essential for DNA-damage induced inflammation. Here, we show that cell cycle progression through mitosis following DNA double-strand breaks (DSBs) leads to the formation of micronuclei, which precede activation of inflammatory signaling and are a repository for the pattern recognition receptor cGAS. Inhibiting progression through mitosis or loss of pattern recognition by cGAS-STING impaired interferon signaling and prevented the regression of abscopal tumors in the context of ionizing radiation and immune checkpoint blockade in vivo. These findings implicate temporal modulation of the cell cycle as an important consideration in the context of therapeutic strategies that combine genotoxic agents with immune checkpoint blockade.

scholarly journals The chromatin-remodeling factor CHD4 coordinates signaling and repair after DNA damage

2010 ◽  
Vol 190 (5) ◽  
pp. 731-740 ◽  
Author(s):  
Dorthe Helena Larsen ◽  
Catherine Poinsignon ◽  
Thorkell Gudjonsson ◽  
Christoffel Dinant ◽  
Mark R. Payne ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Repair ◽  
Chromatin Remodeling ◽  
Cell Cycle Progression ◽  
Clonogenic Survival ◽  
Dna Double Strand Breaks ◽  
Checkpoint Signaling ◽  
Strand Breaks ◽  
Delay Cell

In response to ionizing radiation (IR), cells delay cell cycle progression and activate DNA repair. Both processes are vital for genome integrity, but the mechanisms involved in their coordination are not fully understood. In a mass spectrometry screen, we identified the adenosine triphosphate–dependent chromatin-remodeling protein CHD4 (chromodomain helicase DNA-binding protein 4) as a factor that becomes transiently immobilized on chromatin after IR. Knockdown of CHD4 triggers enhanced Cdc25A degradation and p21Cip1 accumulation, which lead to more pronounced cyclin-dependent kinase inhibition and extended cell cycle delay. At DNA double-strand breaks, depletion of CHD4 disrupts the chromatin response at the level of the RNF168 ubiquitin ligase, which in turn impairs local ubiquitylation and BRCA1 assembly. These cell cycle and chromatin defects are accompanied by elevated spontaneous and IR-induced DNA breakage, reduced efficiency of DNA repair, and decreased clonogenic survival. Thus, CHD4 emerges as a novel genome caretaker and a factor that facilitates both checkpoint signaling and repair events after DNA damage.

scholarly journals DNA Damage-Induced Cell Cycle Regulation and Function of Novel Chk2 Phosphoresidues

2006 ◽  
Vol 26 (21) ◽  
pp. 7832-7845 ◽  
Author(s):  
Giacomo Buscemi ◽  
Luigi Carlessi ◽  
Laura Zannini ◽  
Sofia Lisanti ◽  
Enrico Fontanella ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Ataxia Telangiectasia ◽  
Dna Double Strand Breaks ◽  
Independent Manner ◽  
Strand Breaks ◽  
Cycle Arrest ◽  
And Function ◽  
Cycle Regulation

ABSTRACT Chk2 kinase is activated by DNA damage to regulate cell cycle arrest, DNA repair, and apoptosis. Phosphorylation of Chk2 in vivo by ataxia telangiectasia-mutated (ATM) on threonine 68 (T68) initiates a phosphorylation cascade that promotes the full activity of Chk2. We identified three serine residues (S19, S33, and S35) on Chk2 that became phosphorylated in vivo rapidly and exclusively in response to ionizing radiation (IR)-induced DNA double-strand breaks in an ATM- and Nbs1-dependent but ataxia telangiectasia- and Rad3-related-independent manner. Phosphorylation of these residues, restricted to the G1 phase of the cell cycle, was induced by a higher dose of IR (>1 Gy) than that required for phosphorylation of T68 (0.25 Gy) and declined by 45 to 90 min, concomitant with a rise in Chk2 autophosphorylation. Compared to the wild-type form, Chk2 with alanine substitutions at S19, S33, and S35 (Chk2S3A) showed impaired dimerization, defective auto- and trans-phosphorylation activities, and reduced ability to promote degradation of Hdmx, a phosphorylation target of Chk2 and regulator of p53 activity. Besides, Chk2S3A failed to inhibit cell growth and, in response to IR, to arrest G1/S progression. These findings underscore the critical roles of S19, S33, and S35 and argue that these phosphoresidues may serve to fine-tune the ATM-dependent response of Chk2 to increasing amounts of DNA damage.

scholarly journals Dual roles of yeast Rad51 N-terminal domain in repairing DNA double-strand breaks

2020 ◽  
Vol 48 (15) ◽  
pp. 8474-8489
Author(s):  
Tai-Ting Woo ◽  
Chi-Ning Chuang ◽  
Mika Higashide ◽  
Akira Shinohara ◽  
Ting-Fang Wang
Keyword(s):  
Dna Damage ◽  
Cell Cycle Progression ◽  
Degradation Pathway ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Dual Roles ◽  
Strand Breaks ◽  
Terminal Domain ◽  
High Level

Abstract Highly toxic DNA double-strand breaks (DSBs) readily trigger the DNA damage response (DDR) in cells, which delays cell cycle progression to ensure proper DSB repair. In Saccharomyces cerevisiae, mitotic S phase (20–30 min) is lengthened upon DNA damage. During meiosis, Spo11-induced DSB onset and repair lasts up to 5 h. We report that the NH2-terminal domain (NTD; residues 1–66) of Rad51 has dual functions for repairing DSBs during vegetative growth and meiosis. Firstly, Rad51-NTD exhibits autonomous expression-enhancing activity for high-level production of native Rad51 and when fused to exogenous β-galactosidase in vivo. Secondly, Rad51-NTD is an S/T-Q cluster domain (SCD) harboring three putative Mec1/Tel1 target sites. Mec1/Tel1-dependent phosphorylation antagonizes the proteasomal degradation pathway, increasing the half-life of Rad51 from ∼30 min to ≥180 min. Our results evidence a direct link between homologous recombination and DDR modulated by Rad51 homeostasis.

scholarly journals Comutations in DNA Damage Response Pathways Serve as Potential Biomarkers for Immune Checkpoint Blockade

2018 ◽  
Vol 78 (22) ◽  
pp. 6486-6496 ◽  
Author(s):  
Zhijie Wang ◽  
Jing Zhao ◽  
Guoqiang Wang ◽  
Fan Zhang ◽  
Zemin Zhang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Immune Checkpoint ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Damage Response ◽  
Potential Biomarkers

scholarly journals βarrestin-1 regulates DNA repair by acting as an E3-ubiquitin ligase adaptor for 53BP1

2019 ◽  
Vol 27 (4) ◽  
pp. 1200-1213 ◽  
Author(s):  
Ainhoa Nieto ◽  
Makoto R. Hara ◽  
Victor Quereda ◽  
Wayne Grant ◽  
Vanessa Saunders ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ionizing Radiation ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Molecular Scaffold ◽  
Strand Breaks

Abstract Cellular DNA is constantly under threat from internal and external insults, consequently multiple pathways have evolved to maintain chromosomal fidelity. Our previous studies revealed that chronic stress, mediated by continuous stimulation of the β2-adrenergic-βarrestin-1 signaling axis suppresses activity of the tumor suppressor p53 and impairs genomic integrity. In this pathway, βarrestin-1 (βarr1) acts as a molecular scaffold to promote the binding and degradation of p53 by the E3-ubiquitin ligase, MDM2. We sought to determine whether βarr1 plays additional roles in the repair of DNA damage. Here we demonstrate that in mice βarr1 interacts with p53-binding protein 1 (53BP1) with major consequences for the repair of DNA double-strand breaks. 53BP1 is a principle component of the DNA damage response, and when recruited to the site of double-strand breaks in DNA, 53BP1 plays an important role coordinating repair of these toxic lesions. Here, we report that βarr1 directs 53BP1 degradation by acting as a scaffold for the E3-ubiquitin ligase Rad18. Consequently, knockdown of βarr1 stabilizes 53BP1 augmenting the number of 53BP1 DNA damage repair foci following exposure to ionizing radiation. Accordingly, βarr1 loss leads to a marked increase in irradiation resistance both in cells and in vivo. Thus, βarr1 is an important regulator of double strand break repair, and disruption of the βarr1/53BP1 interaction offers an attractive strategy to protect cells against high levels of exposure to ionizing radiation.

scholarly journals Methyl methanesulfonate (MMS) produces heat-labile DNA damage but no detectable in vivo DNA double-strand breaks

2012 ◽  
Vol 40 (12) ◽  
pp. 5794-5794
Author(s):  
C. Lundin ◽  
M. North ◽  
K. Erixon ◽  
K. Walters ◽  
D. Jenssen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Double Strand Breaks ◽  
Methyl Methanesulfonate ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Heat Labile

scholarly journals Cannabinoids Inhibited Pancreatic Cancer via P-21 Activated Kinase 1 Mediated Pathway

2020 ◽  
Vol 21 (21) ◽  
pp. 8035
Author(s):  
Yang Yang ◽  
Nhi Huynh ◽  
Chelsea Dumesny ◽  
Kai Wang ◽  
Hong He ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Immune Checkpoint ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Pancreatic Stellate Cells ◽  
Inhibitory Effects ◽  
Anti Cancer ◽  
Pancreatic Tumour ◽  
Mouse Study

The anti-cancer effects of cannabinoids including CBD (Cannabidiol) and THC ((−)-trans-∆9-tetrahydrocannabinol) have been reported in the case of pancreatic cancer (PC). The connection of these cannabinoids to KRas oncogenes that mutate in more than 90% of PC, and their effects on PD-L1, a key target of immune checkpoint blockade, have not been thoroughly investigated. Using cell lines and mouse models of PC, the effects of CBD and THC on cancer growth, the interaction between PC cells and a stromal cell, namely pancreatic stellate cells (PSCs), and the mechanism(s) involved were determined by cell-based assays and mouse study in vivo. CBD and THC inhibited the proliferation of PC, PSC, and PSC-stimulated PC cells. They also suppressed pancreatic tumour growth in mice. Furthermore, CBD and/or THC reduced the expression of PD-L1 by either PC or PSC cells. Knockout of p-21 activated kinase 1 (PAK1, activated by KRas) in PC and PSC cells and, in mice, dramatically decreased or blocked these inhibitory effects of CBD and/or THC. These results indicated that CBD and THC exerted their inhibitions on PC and PSC via a p-21 activated kinase 1 (PAK1)-dependent pathway, suggesting that CBD and THC suppress Kras activated pathway by targeting PAK1. The inhibition by CBD and THC of PD-L1 expression will enhance the immune checkpoint blockade of PC.

scholarly journals Dimethoate Induces DNA Damage and Mitochondrial Dysfunction Triggering Apoptosis in Rat Bone-Marrow and Peripheral Blood Cells

Toxics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 80
Author(s):  
Nazia Nazam ◽  
Mohammad Iqbal Lone ◽  
Abid Hamid ◽  
Talal Qadah ◽  
Alaa Banjar ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Bone Marrow ◽  
Dna Damage ◽  
Peripheral Blood ◽  
Cell Cycle Progression ◽  
Bone Marrow Cells ◽  
Multiple Treatment ◽  
Cellular Apoptosis ◽  
Cyclin A2

Dimethoate (DM) is an organophosphorus (OP) pesticide with wide use in the pest control. Its persistence in crops and soils could possibly cause adverse health consequences in humans as well as other non-target species. Since molecular studies confirming potential genotoxicity of DM have not been previously reported, the acute in vivo toxicological impact was evaluated in Wistar rats. Significant micronuclei induction and metaphase chromosome abnormalities in bone marrow cells exposed to three different DM doses (20, 40 and 60 mg/kg-bw) at multiple treatment durations (24, 48 and 72 h) indicated positive dose response relationship, confirming its genotoxic and cytotoxic potential. Significant mitotic index decrease was seen in dosed animals compared to vehicle control. The study used peripheral blood comet assay, indicating DM-mediated damage to DNA at all exposure levels in a time responsive manner. These assays were found to be an effective, precise, and fast technique with applied value in biomonitoring studies. Cell cycle and apoptosis along with mitochondrial membrane potential (MMP) in flow cytometric analyses confirmed DM exposure decreased MMP, affected the cell cycle, and inflicted DNA damage, which led to cellular apoptosis of leukocytes culminating into immunotoxic effects. The in silico experiments consequently augmented that DM showed acceptable binding energy value for Cyclin A2, suggesting that it could inhibit the cell cycle progression by inhibiting cyclin A2.

scholarly journals KALRN mutations promote antitumor immunity and immunotherapy response in cancer

2020 ◽  
Vol 8 (2) ◽  
pp. e000293
Author(s):  
Mengyuan Li ◽  
Yuxiang Ma ◽  
You Zhong ◽  
Qian Liu ◽  
Canping Chen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Immune Checkpoint ◽  
Antitumor Immunity ◽  
Immune Checkpoint Blockade ◽  
Patients With Cancer ◽  
In Vivo Experiments ◽  
Damage Repair

Backgroundkalirin RhoGEF kinase (KALRN) is mutated in a wide range of cancers. Nevertheless, the association between KALRN mutations and the pathogenesis of cancer remains unexplored. Identification of biomarkers for cancer immunotherapy response is crucial because immunotherapies only show beneficial effects in a subset of patients with cancer.MethodsWe explored the correlation between KALRN mutations and antitumor immunity in 10 cancer cohorts from The Cancer Genome Atlas program by the bioinformatics approach. Moreover, we verified the findings from the bioinformatics analysis with in vitro and in vivo experiments. We explored the correlation between KALRN mutations and immunotherapy response in five cancer cohorts receiving immune checkpoint blockade therapy.ResultsAntitumor immune signatures were more enriched in KALRN-mutated than KALRN-wildtype cancers. Moreover, KALRN mutations displayed significant correlations with increased tumor mutation burden and the microsatellite instability or DNA damage repair deficiency genomic properties, which may explain the high antitumor immunity in KALRN-mutated cancers. Also, programmed cell death 1 ligand (PD-L1) expression was markedly upregulated in KALRN-mutated versus KALRN-wildtype cancers. The increased antitumor immune signatures and PD-L1 expression in KALRN-mutated cancers may favor the response to immune checkpoint blockade therapy in this cancer subtype, as evidenced in five cancer cohorts receiving antiprogrammed cell death protein 1 (PD-1)/PD-L1/cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) immunotherapy. Furthermore, the significant association between KALRN mutations and increased antitumor immunity was associated with the fact that KALRN mutations compromised the function of KALRN in targeting Rho GTPases for the regulation of DNA damage repair pathways. In vitro and in vivo experiments validated the association of KALRN deficiency with antitumor immunity and the response to immune checkpoint inhibitors.ConclusionsThe KALRN mutation is a useful biomarker for predicting the response to immunotherapy in patients with cancer.

scholarly journals Sustained CHK2 activity, but not ATM activity, is critical to maintain a G1 arrest after DNA damage in untransformed cells

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Iraia García-Santisteban ◽  
Alba Llopis ◽  
Lenno Krenning ◽  
Jon Vallejo-Rodríguez ◽  
Bram van den Broek ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Cycle Progression ◽  
Double Strand Breaks ◽  
G1 Arrest ◽  
Dna Double Strand Breaks ◽  
Independent Manner ◽  
Cycle Progression ◽  
Strand Breaks ◽  
G1 Checkpoint ◽  
The Impact

Abstract Background The G1 checkpoint is a critical regulator of genomic stability in untransformed cells, preventing cell cycle progression after DNA damage. DNA double-strand breaks (DSBs) recruit and activate ATM, a kinase which in turn activates the CHK2 kinase to establish G1 arrest. While the onset of G1 arrest is well understood, the specific role that ATM and CHK2 play in regulating G1 checkpoint maintenance remains poorly characterized. Results Here we examine the impact of ATM and CHK2 activities on G1 checkpoint maintenance in untransformed cells after DNA damage caused by DSBs. We show that ATM becomes dispensable for G1 checkpoint maintenance as early as 1 h after DSB induction. In contrast, CHK2 kinase activity is necessary to maintain the G1 arrest, independently of ATM, ATR, and DNA-PKcs, implying that the G1 arrest is maintained in a lesion-independent manner. Sustained CHK2 activity is achieved through auto-activation and its acute inhibition enables cells to abrogate the G1-checkpoint and enter into S-phase. Accordingly, we show that CHK2 activity is lost in cells that recover from the G1 arrest, pointing to the involvement of a phosphatase with fast turnover. Conclusion Our data indicate that G1 checkpoint maintenance relies on CHK2 and that its negative regulation is crucial for G1 checkpoint recovery after DSB induction.

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