Functional Study of Haemophilus ducreyi Cytolethal Distending Toxin Subunit B

The Cytolethal Distending Toxin (CDT) is produced by many Gram-negative pathogenic bacteria responsible for major foodborne diseases worldwide. CDT induces DNA damage and cell cycle arrest in host-cells, eventually leading to senescence or apoptosis. According to structural and sequence comparison, the catalytic subunit CdtB is suggested to possess both nuclease and phosphatase activities, carried by a single catalytic site. However, the impact of each activity on cell-host toxicity is yet to be characterized. Here, we analyze the consequences of cell exposure to different CDT mutated on key CdtB residues, focusing on cell viability, cell cycle defects, and DNA damage induction. A first class of mutant, devoid of any activity, targets putative catalytic (H160A), metal binding (D273R), and DNA binding residues (R117A-R144A-N201A). The second class of mutants (A163R, F156-T158, and the newly identified G114T), which gathers mutations on residues potentially involved in lipid substrate binding, has only partially lost its toxic effects. However, their defects are alleviated when CdtB is artificially introduced inside cells, except for the F156-T158 double mutant that is defective in nuclear addressing. Therefore, our data reveal that CDT toxicity is mainly correlated to CdtB nuclease activity, whereas phosphatase activity may probably be involved in CdtB intracellular trafficking.

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Artesunate Impairs Growth in Cisplatin-Resistant Bladder Cancer Cells by Cell Cycle Arrest, Apoptosis and Autophagy Induction

Cells ◽

10.3390/cells9122643 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2643

Author(s):

Fuguang Zhao ◽

Olesya Vakhrusheva ◽

Sascha D. Markowitsch ◽

Kimberly S. Slade ◽

Igor Tsaur ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Bladder Cancer ◽

Cell Growth ◽

Significant Inhibition ◽

Cycle Arrest ◽

Damage Repair ◽

Autophagy Induction ◽

Cell Growth And Proliferation ◽

The Impact

Cisplatin, which induces DNA damage, is standard chemotherapy for advanced bladder cancer (BCa). However, efficacy is limited due to resistance development. Since artesunate (ART), a derivative of artemisinin originating from Traditional Chinese Medicine, has been shown to exhibit anti-tumor activity, and to inhibit DNA damage repair, the impact of artesunate on cisplatin-resistant BCa was evaluated. Cisplatin-sensitive (parental) and cisplatin-resistant BCa cells, RT4, RT112, T24, and TCCSup, were treated with ART (1–100 µM). Cell growth, proliferation, and cell cycle phases were investigated, as were apoptosis, necrosis, ferroptosis, autophagy, metabolic activity, and protein expression. Exposure to ART induced a time- and dose-dependent significant inhibition of tumor cell growth and proliferation of parental and cisplatin-resistant BCa cells. This inhibition was accompanied by a G0/G1 phase arrest and modulation of cell cycle regulating proteins. ART induced apoptos is by enhancing DNA damage, especially in the resistant cells. ART did not induce ferroptosis, but led to a disturbance of mitochondrial respiration and ATP generation. This impairment correlated with autophagy accompanied by a decrease in LC3B-I and an increase in LC3B-II. Since ART significantly inhibits proliferative and metabolic aspects of cisplatin-sensitive and cisplatin-resistant BCa cells, it may hold potential in treating advanced and therapy-resistant BCa.

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Cytolethal Distending Toxin: from mitotic DNA damage to cGAS-dependent pro-inflammatory response

10.1101/2020.06.09.141648 ◽

2020 ◽

Author(s):

Benoît J. Pons ◽

Aurélie Pettes-Duler ◽

Claire Naylies ◽

Frédéric Taieb ◽

Saleha Hashim ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cellular Response ◽

Cell Cycle Checkpoints ◽

Host Cells ◽

Cytolethal Distending Toxin ◽

Dna Damaging Agents ◽

Damage Response ◽

Precise Relationship ◽

First Time

AbstractThe Cytolethal Distending Toxin (CDT) is a bacterial genotoxin that activates the DNA damage response and induces inflammatory signatures in host cells, but the precise relationship between these outcomes has not been addressed so far. CDT induces a singular time-dependent increase of DNA damage and cell cycle defects, questioning on possible impaired response to this toxin over the cell cycle. Here, we identify mitosis as a crucial phase during CDT intoxination. Despite active cell cycle checkpoints and in contrast to other DNA damaging agents, CDT-exposed cells reach mitosis where they accumulate massive DNA damage, resulting in chromosome fragmentation and micronucleus formation. These micronuclei are recognized by cGAS that elicits an inflammatory signature resulting in cell distention and senescence. Our results unravel for the first time the mitotic consequences of CDT genotoxic activity and relate them to pro-inflammatory cellular response. These findings may have important implications during bacterial infection regarding CDT-mediated immunomodulatory and tumorigenic processes.

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Involvement of Ganglioside GM3 in G2/M Cell Cycle Arrest of Human Monocytic Cells Induced by Actinobacillus actinomycetemcomitans Cytolethal Distending Toxin

Infection and Immunity ◽

10.1128/iai.73.8.4846-4852.2005 ◽

2005 ◽

Vol 73 (8) ◽

pp. 4846-4852 ◽

Cited By ~ 40

Author(s):

Koji Mise ◽

Sumio Akifusa ◽

Shinobu Watarai ◽

Toshihiro Ansai ◽

Tatsuji Nishihara ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cell Cycle Arrest ◽

Nuclear Dna ◽

Actinobacillus Actinomycetemcomitans ◽

Cytolethal Distending Toxin ◽

M Cell ◽

Synthesis Inhibitor ◽

Ganglioside Gm3 ◽

Cycle Arrest

ABSTRACT Actinobacillus actinomycetemcomitans produces a toxin called cytolethal distending toxin (CDT), which causes host cell DNA damage leading to the induction of DNA damage checkpoint pathways. CDT consists of three subunits, CdtA, CdtB, and CdtC. CdtB is the active subunit of CDT and exerts its effect as a nuclease that damages nuclear DNA, triggering cell cycle arrest. In the present study, we confirmed that the only combination of toxin proteins causing cell cycle arrest was that of all three recombinant CDT (rCDT) protein subunits. Furthermore, in order for rCDT to demonstrate toxicity, it was necessary for CdtA and CdtC to access the cell before CdtB. The coexistence of CdtA and CdtC was necessary for these subunits to bind to the cell. Cells treated with the glucosylceramide synthesis inhibitor 1-phenyl-2-palmitoylamino-3-morpholino-1-propanol showed resistance to the cytotoxicity induced by rCDT. Furthermore, LY-B cells, which are deficient in the biosynthesis of sphingolipid, also showed resistance to the cytotoxicity induced by rCDT. To evaluate the binding of each subunit for glucosylceramides, we performed thin-layer chromatography immunostaining. The results indicated that each subunit reacted with the glycosphingolipids GM1, GM2, GM3, Gb3, and Gb4. The rCDT mixture incubated with liposomes containing GM3 displayed partially reduced toxicity. These results indicate that GM3 can act as a CDT receptor.

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Cholesterol Depletion Reduces Entry of Campylobacter jejuni Cytolethal Distending Toxin and Attenuates Intoxication of Host Cells

Infection and Immunity ◽

10.1128/iai.05175-11 ◽

2011 ◽

Vol 79 (9) ◽

pp. 3563-3575 ◽

Cited By ~ 28

Author(s):

Chia-Der Lin ◽

Cheng-Kuo Lai ◽

Yu-Hsin Lin ◽

Jer-Tsong Hsieh ◽

Yu-Ting Sing ◽

...

Keyword(s):

Cell Cycle ◽

Cell Cycle Arrest ◽

Lipid Rafts ◽

Campylobacter Jejuni ◽

Host Cells ◽

Membrane Cholesterol ◽

Cholesterol Depletion ◽

Cytolethal Distending Toxin ◽

Content Type ◽

Cycle Arrest

ABSTRACTCampylobacter jejuniis a common cause of pediatric diarrhea worldwide. Cytolethal distending toxin, produced byCampylobacter jejuni, is a putative virulence factor that induces cell cycle arrest and apoptosis in eukaryotic cells. Cellular cholesterol, a major component of lipid rafts, has a pivotal role in regulating signaling transduction and protein trafficking as well as pathogen internalization. In this study, we demonstrated that cell intoxication byCampylobacter jejunicytolethal distending toxin is through the association of cytolethal distending toxin subunits and membrane cholesterol-rich microdomains. Cytolethal distending toxin subunits cofractionated with detergent-resistant membranes, while the distribution reduced upon the depletion of cholesterol, suggesting that cytolethal distending toxin subunits are associated with lipid rafts. The disruption of cholesterol using methyl-β-cyclodextrin not only reduced the binding activity of cytolethal distending toxin subunits on the cell membrane but also impaired their delivery and attenuated toxin-induced cell cycle arrest. Accordingly, cell intoxication by cytolethal distending toxin was restored by cholesterol replenishment. These findings suggest that membrane cholesterol plays a critical role in theCampylobacter jejunicytolethal distending toxin-induced pathogenesis of host cells.

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The Cytolethal Distending Toxin Produced by Nontyphoidal Salmonella Serotypes Javiana, Montevideo, Oranienburg, and Mississippi Induces DNA Damage in a Manner Similar to That of Serotype Typhi

mBio ◽

10.1128/mbio.02109-16 ◽

2016 ◽

Vol 7 (6) ◽

Cited By ~ 23

Author(s):

Rachel A. Miller ◽

Martin Wiedmann

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cell Cycle Arrest ◽

Virulence Factor ◽

Hela Cells ◽

The United States ◽

Cytolethal Distending Toxin ◽

M Cell ◽

Cycle Arrest ◽

Important Virulence Factor

ABSTRACT Select nontyphoidal Salmonella enterica (NTS) serotypes were recently found to encode the Salmonella cytolethal distending toxin (S-CDT), an important virulence factor for serotype Typhi, the causative agent of typhoid fever. Using a PCR-based assay, we determined that among 21 NTS serotypes causing the majority of food-borne salmonellosis cases in the United States, genes encoding S-CDT are conserved in isolates representing serotypes Javiana, Montevideo, and Oranienburg but that among serotype Mississippi isolates, the presence of S-CDT-encoding genes is clade associated. HeLa cells infected with representative strains of these S-CDT-positive serotypes had a significantly higher proportion of cells arrested in the G 2 /M phase than HeLa cells infected with representative strains of S-CDT-negative serotypes Typhimurium, Newport, and Enteritidis. The G 2 /M cell cycle arrest was dependent on CdtB, the active subunit of S-CDT, as infection with isogenic Δ cdtB mutants abolished their ability to induce a G 2 /M cell cycle arrest. Infection with S-CDT-encoding serotypes was significantly associated with activation of the host cell’s DNA damage response (DDR), a signaling cascade that is important for detecting and repairing damaged DNA. HeLa cell populations infected with S-CDT-positive serotypes had a significantly higher proportion of cells with DDR protein 53BP1 and γH2AX foci than cells infected with either S-CDT-negative serotypes or isogenic Δ cdtB strains. Intoxication with S-CDT occurred via autocrine and paracrine pathways, as uninfected HeLa cells among populations of infected cells also had an activated DDR. Overall, we show that S-CDT plays a significant role in the cellular outcome of infection with NTS serotypes. IMPORTANCE The recent discovery that multiple serotypes encode S-CDT, which was previously established as an important virulence factor for serotype Typhi, suggested that this toxin may also contribute to the outcome of infection with nontyphoidal serotypes. In this study, we demonstrate that at a cellular level, S-CDT significantly alters the outcome of infection by inducing DNA damage which is associated with a cell cycle arrest and activation of the host cell’s DDR. Importantly, these results contribute valuable information for assessing the public health implications of S-CDT in infections with NTS serotypes. Our data suggest that infection with Salmonella strains that encode S-CDT has the potential to result in DNA damage, which may contribute to long-term sequelae.

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Cytolethal Distending Toxin from Aggregatibacter actinomycetemcomitans Induces DNA Damage, S/G2 Cell Cycle Arrest, and Caspase- Independent Death in a Saccharomyces cerevisiae Model

Infection and Immunity ◽

10.1128/iai.00857-09 ◽

2009 ◽

Vol 78 (2) ◽

pp. 783-792 ◽

Cited By ~ 21

Author(s):

Oranart Matangkasombut ◽

Roongtiwa Wattanawaraporn ◽

Keiko Tsuruda ◽

Masaru Ohara ◽

Motoyuki Sugai ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Dna Damage ◽

Cell Death ◽

Cell Cycle Arrest ◽

Aggregatibacter Actinomycetemcomitans ◽

Cytolethal Distending Toxin ◽

Dependent Manner ◽

Cycle Arrest ◽

Yeast Strains

ABSTRACT Cytolethal distending toxin (CDT) is a bacterial toxin that induces G2/M cell cycle arrest, cell distension, and/or apoptosis in mammalian cells. It is produced by several Gram-negative species and may contribute to their pathogenicity. The catalytic subunit CdtB has homology with DNase I and may act as a genotoxin. However, the mechanism by which CdtB leads to cell death is not yet clearly understood. Here, we used Saccharomyces cerevisiae as a model to study the molecular pathways involved in the function of CdtB from Aggregatibacter actinomycetemcomitans, a cause of aggressive periodontitis. We show that A. actinomycetemcomitans CdtB (AaCdtB) expression induces S/G2 arrest and death in a DNase-catalytic residue and nuclear localization-dependent manner in haploid yeasts. Yeast strains defective in homologous recombination (HR) repair, but not other DNA repair pathways, are hypersensitive to AaCdtB, suggesting that HR is required for survival upon CdtB expression. In addition, yeast does not harbor the substrate for the other activity proposed for CdtB function, which is phosphatidylinositol-3,4,5-triphosphate phosphatase. Thus, these results suggest that direct DNA-damaging activity alone is sufficient for CdtB toxicity. To investigate how CdtB induces cell death, we examined the effect of CdtB in yeast strains with mutations in apoptotic regulators. Our results suggest that yeast death occurs independently of the yeast metacaspase gene YCA1 and the apoptosis-inducing factor AIF1 but is partially dependent on histone H2B serine 10 phosphorylation. Therefore, we report here the evidence that AaCdtB causes DNA damage that leads to nonapoptotic death in yeast and the first mutation that confers resistance to CdtB.

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The proinflammatory response induced by the Cytolethal Distending Toxin depends on cGAS

10.21203/rs.3.rs-162979/v1 ◽

2021 ◽

Author(s):

Benoît J. Pons ◽

Aurélie Pettes-Duler ◽

Claire Naylies ◽

Frédéric Taieb ◽

Catherine Bouchenot ◽

...

Keyword(s):

Dna Damage ◽

Pathogenic Bacteria ◽

Natural Infection ◽

Cell Cycle Checkpoints ◽

Host Cells ◽

Cytolethal Distending Toxin ◽

Proinflammatory Response ◽

Cytoplasmic Dna ◽

Cellular Inflammatory Response ◽

Precise Relationship

Abstract The Cytolethal Distending Toxin (CDT) is a bacterial genotoxin produced by pathogenic bacteria causing major foodborne diseases worldwide. CDT activates the DNA damage response and induces inflammatory signatures in host cells, but the precise relationship between these outcomes has not been addressed so far. Here, we show that the cellular proinflammatory response and senescence induced by CDT depend on the cytoplasmic DNA sensor cGAS through the recognition of micronuclei. Indeed, despite active cell cycle checkpoints and in contrast to other DNA damaging agents, cells exposed to CDT reach mitosis where they accumulate massive DNA damage, resulting in chromosome fragmentation and micronucleus formation in daughter cells. These phenotypes are observed with CDT from various origins and in cancer or normal cell lines. Thus, our results establish a direct link between CDT-induced DNA damage, genetic instability and the cellular inflammatory response that may be relevant in the context of natural infection associated to chronic inflammation or carcinogenesis.

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A Novel Camptothecin Derivative 3j Inhibits Nsclc Proliferation Via Induction of Cell Cycle Arrest By Topo I-Mediated DNA Damage

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520619666181207102037 ◽

2019 ◽

Vol 19 (3) ◽

pp. 365-374 ◽

Cited By ~ 1

Author(s):

Yang Liu ◽

Jingyin Zhang ◽

Shuyun Feng ◽

Tingli Zhao ◽

Zhengzheng Li ◽

...

Keyword(s):

Cell Cycle ◽

Flow Cytometry ◽

Dna Damage ◽

Cyclin D ◽

Dna Relaxation ◽

Cycle Arrest ◽

H460 Cell ◽

H1975 Cell

Objective: The aim of this study is to investigate the inhibitory effect of camptothecin derivative 3j on Non-Small Cell Lung Cancer (NSCLCs) cells and the potential anti-tumor mechanisms. Background: Camptothecin compounds are considered as the third largest natural drugs which are widely investigated in the world and they suffered restriction because of serious toxicity, such as hemorrhagic cystitis and bone marrow suppression. Methods: Using cell proliferation assay and S180 tumor mice model, a series of 20(S)-O-substituted benzoyl 7- ethylcamptothecin compounds were screened and evaluated the antitumor activities in vitro and in vivo. Camptothecin derivative 3j was selected for further study using flow cytometry in NSCLCs cells. Cell cycle related protein cyclin A2, CDK2, cyclin D and cyclin E were detected by Western Blot. Then, computer molecular docking was used to confirm the interaction between 3j and Topo I. Also, DNA relaxation assay and alkaline comet assay were used to investigate the mechanism of 3j on DNA damage. Results: Our results demonstrated that camptothecin derivative 3j showed a greater antitumor effect in eleven 20(S)-O-substituted benzoyl 7-ethylcamptothecin compounds in vitro and in vivo. The IC50 of 3j was 1.54± 0.41 µM lower than irinotecan with an IC50 of 13.86±0.80 µM in NCI-H460 cell, which was reduced by 8 fold. In NCI-H1975 cell, the IC50 of 3j was 1.87±0.23 µM lower than irinotecan (IC50±SD, 5.35±0.38 µM), dropped by 1.8 fold. Flow cytometry analysis revealed that 3j induced significant accumulation in a dose-dependent manner. After 24h of 3j (10 µM) treatment, the percentage of NCI-H460 cell in S-phase significantly increased (to 93.54 ± 4.4%) compared with control cells (31.67 ± 3.4%). Similarly, the percentage of NCI-H1975 cell in Sphase significantly increased (to 83.99 ± 2.4%) compared with control cells (34.45 ± 3.9%) after treatment with 10µM of 3j. Moreover, increased levels of cyclin A2, CDK2, and decreased levels of cyclin D, cyclin E further confirmed that cell cycle arrest was induced by 3j. Furthermore, molecular docking studies suggested that 3j interacted with Topo I-DNA and DNA-relaxation assay simultaneously confirmed that 3j suppressed the activity of Topo I. Research on the mechanism showed that 3j exhibited anti-tumour activity via activating the DNA damage response pathway and suppressing the repair pathway in NSCLC cells. Conclusion: Novel camptothecin derivative 3j has been demonstrated as a promising antitumor agent and remains to be assessed in further studies.

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Design, Synthesis and Pharmacological Evaluation of Three Novel Dehydroabietyl Piperazine Dithiocarbamate Ruthenium (II) Polypyridyl Complexes as Potential Antitumor Agents: DNA Damage, Cell Cycle Arrest and Apoptosis Induction

Molecules ◽

10.3390/molecules26051453 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1453

Author(s):

Haoran Wang ◽

Jianhua Wei ◽

Hong Jiang ◽

Ye Zhang ◽

Caina Jiang ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cell Cycle Arrest ◽

Antitumor Agents ◽

Mechanistic Study ◽

Ros Generation ◽

Polypyridyl Complexes ◽

Expression Levels ◽

Cycle Arrest ◽

Study Results

The use of cisplatin is severely limited by its toxic side-effects, which has spurred chemists to employ different strategies in the development of new metal-based anticancer agents. Here, three novel dehydroabietyl piperazine dithiocarbamate ruthenium (II) polypyridyl complexes (6a–6c) were synthesized as antitumor agents. Compounds 6a and 6c exhibited better in vitro antiproliferative activity against seven tumor cell lines than cisplatin, they displayed no evident resistance in the cisplatin-resistant cell line A549/DPP. Importantly, 6a effectively inhibited tumor growth in the T-24 xenograft mouse model in comparison with cisplatin. Gel electrophoresis assay indicated that DNA was the potential targets of 6a and 6c, and the upregulation of p-H2AX confirmed this result. Cell cycle arrest studies demonstrated that 6a and 6c arrested the cell cycle at G1 phase, accompanied by the upregulation of the expression levels of the antioncogene p27 and the down-regulation of the expression levels of cyclin E. In addition, 6a and 6c caused the apoptosis of tumor cells along with the upregulation of the expression of Bax, caspase-9, cytochrome c, intracellular Ca2+ release, reactive oxygen species (ROS) generation and the downregulation of Bcl-2. These mechanistic study results suggested that 6a and 6c exerted their antitumor activity by inducing DNA damage, and consequently causing G1 stage arrest and the induction of apoptosis.

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