scholarly journals DNA Alkylation Damage as a Sensor of Nitrosative Stress in Mycobacterium tuberculosis

2003 ◽  
Vol 71 (2) ◽  
pp. 997-1000 ◽  
Author(s):  
Steven I. Durbach ◽  
Burkhard Springer ◽  
Edith E. Machowski ◽  
Robert J. North ◽  
K. G. Papavinasasundaram ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mycobacterium Tuberculosis ◽  
Nitrosative Stress ◽  
Dna Alkylation ◽  
Genotoxic Effects ◽  
Alkylation Damage ◽  
Damage Repair

ABSTRACT One of the cellular consequences of nitrosative stress is alkylation damage to DNA. To assess whether nitrosative stress is registered on the genome of Mycobacterium tuberculosis, mutants lacking an alkylation damage repair and reversal operon were constructed. Although hypersensitive to the genotoxic effects of N-methyl-N′-nitro-N-nitrosoguanidine in vitro, the mutants displayed no phenotype in vivo, suggesting that permeation of nitrosative stress to the level of cytotoxic DNA damage is restricted.

scholarly journals LINC-PINT impedes DNA repair and enhances radiotherapeutic response by targeting DNA-PKcs in nasopharyngeal cancer

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
You-hong Wang ◽  
Zhen Guo ◽  
Liang An ◽  
Yong Zhou ◽  
Heng Xu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nasopharyngeal Cancer ◽  
Noncoding Rnas ◽  
Dependent Protein Kinase ◽  
Damage Repair ◽  
Dependent Protein ◽  
Cancer Tissues

AbstractRadioresistance continues to be the leading cause of recurrence and metastasis in nasopharyngeal cancer. Long noncoding RNAs are emerging as regulators of DNA damage and radioresistance. LINC-PINT was originally identified as a tumor suppressor in various cancers. In this study, LINC-PINT was significantly downregulated in nasopharyngeal cancer tissues than in rhinitis tissues, and low LINC-PINT expressions showed poorer prognosis in patients who received radiotherapy. We further identified a functional role of LINC-PINT in inhibiting the malignant phenotypes and sensitizing cancer cells to irradiation in vitro and in vivo. Mechanistically, LINC-PINT was responsive to DNA damage, inhibiting DNA damage repair through ATM/ATR-Chk1/Chk2 signaling pathways. Moreover, LINC-PINT increased radiosensitivity by interacting with DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and negatively regulated the expression and recruitment of DNA-PKcs. Therefore, these findings collectively support the possibility that LINC-PINT serves as an attractive target to overcome radioresistance in NPC.

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

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.

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

2009 ◽  
Vol 284 (24) ◽  
pp. 16066-16070 ◽  
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.

scholarly journals Arginine-deprivation–induced oxidative damage sterilizes Mycobacterium tuberculosis

2018 ◽  
Vol 115 (39) ◽  
pp. 9779-9784 ◽  
Author(s):  
Sangeeta Tiwari ◽  
Andries J. van Tonder ◽  
Catherine Vilchèze ◽  
Vitor Mendes ◽  
Sherine E. Thomas ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Mycobacterium Tuberculosis ◽  
De Novo ◽  
Target Space ◽  
Biosynthesis Pathway ◽  
Arginine Biosynthesis ◽  
Arginine Deprivation

Reactive oxygen species (ROS)-mediated oxidative stress and DNA damage have recently been recognized as contributing to the efficacy of most bactericidal antibiotics, irrespective of their primary macromolecular targets. Inhibitors of targets involved in both combating oxidative stress as well as being required for in vivo survival may exhibit powerful synergistic action. This study demonstrates that the de novo arginine biosynthetic pathway in Mycobacterium tuberculosis (Mtb) is up-regulated in the early response to the oxidative stress-elevating agent isoniazid or vitamin C. Arginine deprivation rapidly sterilizes the Mtb de novo arginine biosynthesis pathway mutants ΔargB and ΔargF without the emergence of suppressor mutants in vitro as well as in vivo. Transcriptomic and flow cytometry studies of arginine-deprived Mtb have indicated accumulation of ROS and extensive DNA damage. Metabolomics studies following arginine deprivation have revealed that these cells experienced depletion of antioxidant thiols and accumulation of the upstream metabolite substrate of ArgB or ArgF enzymes. ΔargB and ΔargF were unable to scavenge host arginine and were quickly cleared from both immunocompetent and immunocompromised mice. In summary, our investigation revealed in vivo essentiality of the de novo arginine biosynthesis pathway for Mtb and a promising drug target space for combating tuberculosis.

scholarly journals SIRT7-mediated ATM deacetylation is essential for its deactivation and DNA damage repair

2019 ◽  
Vol 5 (3) ◽  
pp. eaav1118 ◽  
Author(s):  
Ming Tang ◽  
Zhiming Li ◽  
Chaohua Zhang ◽  
Xiaopeng Lu ◽  
Bo Tu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Repair ◽  
Class Iii ◽  
Ataxia Telangiectasia Mutated ◽  
Damage Repair ◽  
Damage Response ◽  
Late Stages

The activation of ataxia-telangiectasia mutated (ATM) upon DNA damage involves a cascade of reactions, including acetylation by TIP60 and autophosphorylation. However, how ATM is progressively deactivated after completing DNA damage repair remains obscure. Here, we report that sirtuin 7 (SIRT7)–mediated deacetylation is essential for dephosphorylation and deactivation of ATM. We show that SIRT7, a class III histone deacetylase, interacts with and deacetylates ATM in vitro and in vivo. In response to DNA damage, SIRT7 is mobilized onto chromatin and deacetylates ATM during the late stages of DNA damage response, when ATM is being gradually deactivated. Deacetylation of ATM by SIRT7 is prerequisite for its dephosphorylation by its phosphatase WIP1. Consequently, depletion of SIRT7 or acetylation-mimic mutation of ATM induces persistent ATM phosphorylation and activation, thus leading to impaired DNA damage repair. Together, our findings reveal a previously unidentified role of SIRT7 in regulating ATM activity and DNA damage repair.

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.

Molecular landscape of gastric cancer (GC) harboring mutations of histone methyltransferases.

2020 ◽  
Vol 38 (4_suppl) ◽  
pp. 418-418
Author(s):  
Jingyuan Wang ◽  
Joanne Xiu ◽  
Yasmine Baca ◽  
Richard M. Goldberg ◽  
Philip Agop Philip ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cancer Progression ◽  
Dna Damage Repair ◽  
Treatment Strategies ◽  
Gene Mutations ◽  
Mutation Rates ◽  
Aberrant Expression ◽  
Damage Repair

418 Background: Alteration of histone modifications participating in transcription and genomic instability, has been recognized as an important role in tumorigenesis. Aberrant expression of histone-lysine N-methyltransferase 2 ( KMT2) family, which methylate histone H3 on lysine 4, is significantly correlated with poor survival in GC. Understanding how gene mutations of KMT2 family interact to affect cancer progression could lead to new treatment strategies. Methods: A total of 1,245 GC were analyzed using next-generation sequencing (NGS) and immunohistochemistry (IHC; Caris Life Sciences, Phoenix, AZ). Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous mutations, and MSI status was evaluated by a combination of IHC, fragment analysis and NGS. PD-L1 status was analyzed by IHC (SP142). Gene fusions were detected by Archer (N = 59) or whole-transcriptome sequencing (N = 129). Results: The overall mutation rate of genes in KMT2 family was 10.6% ( KMT2A: 1.7 %, KMT2C: 4.7%, KMT2D: 7.1%). Overall, the mutation rates were significantly higher in KMT2-mutated (MT) GC than KMT2-wild type (WT) GC, except for TP53 (43% vs 63%, p < .0001). Interestingly, among the genes with significant higher mutation rates in KMT2-MT GC, 28% (21/76) of them were related to DNA damage repair (including BRCA1/ 2, RAD50) and 33% (25/76) of them were related to chromatin remodeling (including ARID1A/ 2, SMARCA4). Overexpression of HER2, amplifications of KRAS, CDK6 and HER2 were significant lower, while PCM1 and BCL3 amplifications were significant higher in KMT2-MT, compared to KMT2-WT GC ( p < .05). Significantly higher prevalence of TMB-high ( > 17mut/MB) (49% vs 3%), MSI-H (53% vs 2%), and PD-L1 overexpression (20% vs 7%) were present in KMT2-MT GC, compared to KMT2-WT GC ( p < .001). The rates of fusions involving ARHGAP26 (19% vs 3%, p < .01)and RELA (29% vs 0%, p < .0001) were significantly higher in KMT2-MT than those in KMT2-WT GC. Conclusions: This is the largest study to investigate the distinct genomic landscape between KMT2-MT and WT GC. Our data indicates that KMT2-MT GC patients could potentially benefit from agents targeting DNA damage repair and immunotherapy, which warrants further in-vitro and in-vivo investigation.

scholarly journals Genotoxic properties of fluorines (review)

2020 ◽  
Vol 99 (3) ◽  
pp. 253-258
Author(s):  
Е.Э. E. Калюжная ◽  
А.Ю. Yu. Просеков ◽  
Валентин Павлович Волобаев
Keyword(s):  
Dna Damage ◽  
In Vivo Studies ◽  
Hydroxyl Group ◽  
Fluoride Ion ◽  
Genotoxic Effects ◽  
Human Environment ◽  
Human Contact ◽  
Professional Contact

Introduction. Consistency of fluoride excess in the human environment and professional contact with fluoride is an actual and underestimated problem. Fluoride ion is able to displace the hydroxyl group in calcium hydroxyapatites, forming stable crystals of mixed form of apatites, inducing bone pathology, fluorosis. Despite the high prevalence of fluorosis, there are only a few studies discussing the ability of fluoride ion to increase the level of genotoxic effects. At the same time, such studies are in high demand in connection with a direct correlation between genetic instability and the risk of carcinogenesis. Material and methods. A literature search was conducted according the following queries: “fluoride, fluoride ion, fluorides, DNA damage, genetic damage, genotoxicity.” The search was conducted on the databases PubMed, MEDLINE, Embase and Google Scholar for various articles (all publications until June 2018). All publications were analyzed and included in this review. Results.The present review examines the results of studies aimed at investigation of the ability of fluoride to induce DNA damage, published since the 50-s of 20th century to the present. The analyse of data about genotoxic and mutagenic properties of fluorine observed in In vitro and In vivo studies is provided. It is summarized that at concentrations of sodium fluoride in drinking water of more than 1 mM, fluoride ion has the ability to induce DNA damage and increase the frequency of clastogenic effects in humans and large monkeys. At the same time, for a significant increase in genotoxic effects in rodents, large concentrations of fluorides are required. The main hypotheses about the mechanisms of the fluoride genotoxic properties are described. Conclusion. Considering results published nowadays, it can be noted that fluoride ion obviously showes a number of genotoxic features and can have mutagenic properties in case of chronic and direct contact with cellular objects. It remains questionable issue about genotoxic risk accompanied human contact with fluoride compounds.

scholarly journals GENOTOXIC PROPERTIES OF FLUORINES (REVIEW)

2020 ◽  
Vol 99 (3) ◽  
pp. 253-258
Author(s):  
E. E. Kalyuzhnaya ◽  
A. Yu. Prosekov ◽  
Valentin P. Volobaev
Keyword(s):  
Dna Damage ◽  
In Vivo Studies ◽  
Hydroxyl Group ◽  
Fluoride Ion ◽  
Genotoxic Effects ◽  
Human Environment ◽  
Human Contact ◽  
Professional Contact

Introduction. Consistency of fluoride excess in the human environment and professional contact with fluoride is an actual and underestimated problem. Fluoride ion is able to displace the hydroxyl group in calcium hydroxyapatites, forming stable crystals of mixed form of apatites, inducing bone pathology, fluorosis. Despite the high prevalence of fluorosis, there are only a few studies discussing the ability of fluoride ion to increase the level of genotoxic effects. At the same time, such studies are in high demand in connection with a direct correlation between genetic instability and the risk of carcinogenesis. Material and methods. A literature search was conducted according the following queries: “fluoride, fluoride ion, fluorides, DNA damage, genetic damage, genotoxicity.” The search was conducted on the databases PubMed, MEDLINE, Embase and Google Scholar for various articles (all publications until June 2018). All publications were analyzed and included in this review. Results.The present review examines the results of studies aimed at investigation of the ability of fluoride to induce DNA damage, published since the 50-s of 20th century to the present. The analyse of data about genotoxic and mutagenic properties of fluorine observed in In vitro and In vivo studies is provided. It is summarized that at concentrations of sodium fluoride in drinking water of more than 1 mM, fluoride ion has the ability to induce DNA damage and increase the frequency of clastogenic effects in humans and large monkeys. At the same time, for a significant increase in genotoxic effects in rodents, large concentrations of fluorides are required. The main hypotheses about the mechanisms of the fluoride genotoxic properties are described. Conclusion. Considering results published nowadays, it can be noted that fluoride ion obviously showes a number of genotoxic features and can have mutagenic properties in case of chronic and direct contact with cellular objects. It remains questionable issue about genotoxic risk accompanied human contact with fluoride compounds.

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