Inhibition of topoisomerase IIα and induction of DNA damage in cholangiocarcinoma cells by altholactone and its halogenated benzoate derivatives

ABSTRACT DNA topoisomerase II is an essential nuclear enzyme that modulates DNA processes by altering the topological state of double-stranded DNA. This enzyme is required for chromosome condensation and segregation; however, the regulatory mechanism of its activation is largely unknown. Here we demonstrate that topoisomerase IIα is activated in response to genotoxic stress. Concomitant with the activation, the expression of topoisomerase IIα is increased following DNA damage. The results also demonstrate that the proapoptotic kinase protein kinase C δ (PKCδ) interacts with topoisomerase IIα. This association is in an S-phase-specific manner and is required for stabilization and catalytic activation of topoisomerase IIα in response to DNA damage. Conversely, inhibition of PKCδ activity attenuates DNA damage-induced activation of topoisomerase IIα. Finally, aberrant activation of topoisomerase IIα by PKCδ is associated with induction of apoptosis upon exposure to genotoxic agents. These findings indicate that PKCδ regulates topoisomerase IIα and thereby cell fate in the genotoxic stress response.

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Repression of CDK1 and Other Genes with CDE and CHR Promoter Elements during DNA Damage-Induced G2/M Arrest in Human Cells

Molecular and Cellular Biology ◽

10.1128/mcb.20.7.2358-2366.2000 ◽

2000 ◽

Vol 20 (7) ◽

pp. 2358-2366 ◽

Cited By ~ 56

Author(s):

Christophe Badie ◽

Jane E. Itzhaki ◽

Matthew J. Sullivan ◽

Adam J. Carpenter ◽

Andrew C. G. Porter

Keyword(s):

Dna Damage ◽

Transcriptional Repression ◽

Human Fibroblasts ◽

Cyclin B1 ◽

Human Cells ◽

Transcriptional Level ◽

Mrna Levels ◽

Cyclin Dependent Kinase ◽

Promoter Regions ◽

Topoisomerase Iiα

ABSTRACT Entry into mitosis is controlled by the cyclin-dependent kinase CDK1 and can be delayed in response to DNA damage. In some systems, such G2/M arrest has been shown to reflect the stabilization of inhibitory phosphorylation sites on CDK1. In human cells, full G2 arrest appears to involve additional mechanisms. We describe here the prolonged (>6 day) downregulation of CDK1 protein and mRNA levels following DNA damage in human cells. This silencing of gene expression is observed in primary human fibroblasts and in two cell lines with functional p53 but not in HeLa cells, where p53 is inactive. Silencing is accompanied by the accumulation of cells in G2, when CDK1 expression is normally maximal. The response is impaired by mutations in cis-acting elements (CDE and CHR) in the CDK1 promoter, indicating that silencing occurs at the transcriptional level. These elements have previously been implicated in the repression of transcription during G1that is normally lifted as cells progress into S and G2. Interestingly, we find that other genes, including those for CDC25C, cyclin A2, cyclin B1, CENP-A, and topoisomerase IIα, that are normally expressed preferentially in G2 and whose promoter regions include putative CDE and CHR elements are also downregulated in response to DNA damage. These data, together with those of other groups, support the existence of a p53-dependent, DNA damage-activated pathway leading to CHR- and CDE-mediated transcriptional repression of various G2-specific genes. This pathway may be required for sustained periods of G2 arrest following DNA damage.

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SUMO1 in human sperm: new targets, role in motility and morphology and relationship with DNA damage

Reproduction ◽

10.1530/rep-14-0173 ◽

2014 ◽

Vol 148 (5) ◽

pp. 453-467 ◽

Cited By ~ 11

Author(s):

S Marchiani ◽

L Tamburrino ◽

B Ricci ◽

D Nosi ◽

M Cambi ◽

...

Keyword(s):

Dna Damage ◽

Human Sperm ◽

Multiple Roles ◽

Sperm Dna Fragmentation ◽

Freezing And Thawing ◽

Topoisomerase Iiα ◽

Ran Gtpase ◽

Mitochondrial Alterations ◽

Sperm Dna ◽

Live Sperm

In studies carried out previously, we demonstrated that small ubiquitin-like modifier 1 (SUMO1) is associated with poor sperm motility when evaluated with a protocol that reveals mostly SUMO1-ylated live sperm. Recently, with another protocol, it has been demonstrated that SUMO is expressed in most sperm and is related to poor morphology and motility, suggesting that sumoylation may have multiple roles depending on its localisation and targets. We show herein, by confocal microscopy and co-immunoprecipitation, that dynamin-related protein 1 (DRP1), Ran GTPase-activating protein 1 (RanGAP1) and Topoisomerase IIα, SUMO1 targets in somatic and/or germ cells, are SUMO1-ylated in mature human spermatozoa. DRP1 co-localises with SUMO1 in the mid-piece, whereas RanGAP1 and Topoisomerase IIα in the post-acrosomal region of the head. Both SUMO1 expression and co-localisation with the three proteins were significantly higher in morphologically abnormal sperm, suggesting that sumoylation represents a marker of defective sperm. DRP1 sumoylation at the mid-piece level was higher in the sperm of asthenospermic men. As in somatic cells, DRP1 sumoylation is associated with mitochondrial alterations, this protein may represent the link between SUMO and poor motility. As SUMO pathways are involved in responses to DNA damage, another aim of our study was to investigate the relationship between sumoylation and sperm DNA fragmentation (SDF). By flow cytometry, we demonstrated that SUMO1-ylation and SDF are correlated (r=0.4,P<0.02,n=37) and most sumoylated sperm shows DNA damage in co-localisation analysis. When SDF was induced by stressful conditions (freezing and thawing and oxidative stress), SUMO1-ylation increased. Following freezing and thawing, SUMO1–Topoisomerase IIα co-localisation and co-immunoprecipitation increased, suggesting an involvement in the formation/repair of DNA breakage.

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ChemInform Abstract: 3-(3-Butylamino-2-hydroxy-propoxy)-1-hydroxy-xanthen-9-one Acts as a Topoisomerase IIα Catalytic Inhibitor with Low DNA Damage.

ChemInform ◽

10.1002/chin.201412138 ◽

2014 ◽

Vol 45 (12) ◽

pp. no-no

Author(s):

So-Eun Park ◽

In-Hye Chang ◽

Kyu-Yeon Jun ◽

Eunyoung Lee ◽

Eung-Seok Lee ◽

...

Keyword(s):

Dna Damage ◽

Topoisomerase Iiα ◽

Catalytic Inhibitor

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Topoisomerase IIα prevents ultrafine anaphase bridges by two mechanisms

Open Biology ◽

10.1098/rsob.190259 ◽

2020 ◽

Vol 10 (5) ◽

pp. 190259

Author(s):

Simon Gemble ◽

Géraldine Buhagiar-Labarchède ◽

Rosine Onclercq-Delic ◽

Gaëlle Fontaine ◽

Sarah Lambert ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Dna Replication ◽

Free Resolution ◽

Cycle Phase ◽

Dependent Manner ◽

Topoisomerase Iiα ◽

Anaphase Bridges ◽

A Cell ◽

Cycle Dependent

Topoisomerase IIα (Topo IIα), a well-conserved double-stranded DNA (dsDNA)-specific decatenase, processes dsDNA catenanes resulting from DNA replication during mitosis. Topo IIα defects lead to an accumulation of ultrafine anaphase bridges (UFBs), a type of chromosome non-disjunction. Topo IIα has been reported to resolve DNA anaphase threads, possibly accounting for the increase in UFB frequency upon Topo IIα inhibition. We hypothesized that the excess UFBs might also result, at least in part, from an impairment of the prevention of UFB formation by Topo IIα. We found that Topo IIα inhibition promotes UFB formation without affecting the global disappearance of UFBs during mitosis, but leads to an aberrant UFB resolution generating DNA damage within the next G1. Moreover, we demonstrated that Topo IIα inhibition promotes the formation of two types of UFBs depending on cell cycle phase. Topo IIα inhibition during S-phase compromises complete DNA replication, leading to the formation of UFB-containing unreplicated DNA, whereas Topo IIα inhibition during mitosis impedes DNA decatenation at metaphase–anaphase transition, leading to the formation of UFB-containing DNA catenanes. Thus, Topo IIα activity is essential to prevent UFB formation in a cell-cycle-dependent manner and to promote DNA damage-free resolution of UFBs.

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