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Endocrine-related Cancer Jul 2017Topoisomerase II alpha (TOP2A) and thymidylate synthase (TS) are known prognostic parameters in several tumors and also predictors of efficacy of anthracyclines,...
Topoisomerase II alpha (TOP2A) and thymidylate synthase (TS) are known prognostic parameters in several tumors and also predictors of efficacy of anthracyclines, topoisomerase inhibitors and fluoropirimidines, respectively. Expression of and mRNA was assessed in 98 patients with adrenocortical carcinoma (ACC) and protein expression was assessed by immunohistochemistry in a subset of 39 tumors. Ninety-two patients were radically resected for stage II-III disease and 38 of them received adjuvant mitotane. Twenty-six patients with metastatic disease received the EDP-M (etoposide, doxorubicin, Adriamycin, cisplatin plus mitotane). and expression in ACC tissue was directly correlated with the clinical data. Both markers were not associated with either disease free survival (DFS) or overall survival (OS) in multivariate analyses and failed to be associated to mitotane efficacy. Disease response or stabilization to EDP-M treatment was observed in 12/17 (71%) and 1/9 (11%) patients with high and low TOP2A expressing tumors ( = 0.0039) and 9/13 (69%) and 4/13 (31%) patients with high and low TS expressing ACC, respectively ( = 0.049). High TOP2A expression was significantly associated with longer time to progression (TTP) after EDP-M. TOP2A and TS proteins assessed by immunohistochemistry significantly correlated with mRNA expression. Immunohistochemical TOP2A expression was associated with a non-significant better response and longer TTP after EDP-M. TOP2A and TS were neither prognostic nor predictive of mitotane efficacy in ACC patients. The predictive role of TOP2A expression of EDP-M activity suggests a significant contribution of Adriamycin and etoposide for the efficacy of the EDP scheme.
Topics: Adolescent; Adrenal Cortex Neoplasms; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; DNA Topoisomerases, Type II; Doxorubicin; Etoposide; Female; Humans; Immunohistochemistry; Male; Middle Aged; Mitotane; RNA, Messenger; Thymidylate Synthase; Young Adult
PubMed: 28432084
DOI: 10.1530/ERC-17-0095 -
MBio Feb 2021Topoisomerases regulate higher-order chromatin structures through the transient breaking and religating of one or both strands of the phosphodiester backbone of duplex...
Topoisomerases regulate higher-order chromatin structures through the transient breaking and religating of one or both strands of the phosphodiester backbone of duplex DNA. TOP2β is a type II topoisomerase that induces double-strand DNA breaks at topologically associated domains (TADS) to relieve torsional stress arising during transcription or replication. TADS are anchored by CCCTC-binding factor (CTCF) and SMC1 cohesin proteins in complexes with TOP2β. Upon DNA cleavage, a covalent intermediate DNA-TOP2β (TOP2βcc) is transiently generated to allow for strand passage. The tyrosyl-DNA phosphodiesterase TDP2 can resolve TOP2βcc, but failure to do so quickly can lead to long-lasting DNA breaks. Given the role of CTCF/SMC1 proteins in the human papillomavirus (HPV) life cycle, we investigated whether TOP2β proteins contribute to HPV pathogenesis. Our studies demonstrated that levels of both TOP2β and TDP2 were substantially increased in cells with high-risk HPV genomes, and this correlated with large amounts of DNA breaks. Knockdown of TOP2β with short hairpin RNAs (shRNAs) reduced DNA breaks by over 50% as determined through COMET assays. Furthermore, this correlated with substantially reduced formation of repair foci such as phosphorylated H2AX (γH2AX), phosphorylated CHK1 (pCHK1), and phosphorylated SMC1 (pSMC1) indicative of impaired activation of DNA damage repair pathways. Importantly, knockdown of TOP2β also blocked HPV genome replication. Our previous studies demonstrated that CTCF/SMC1 factors associate with HPV genomes at sites in the late regions of HPV31, and these correspond to regions that also bind TOP2β. This study identifies TOP2β as responsible for enhanced levels of DNA breaks in HPV-positive cells and as a regulator of viral replication. High-risk human papillomaviruses (HPVs) infect epithelial cells and induce viral genome amplification upon differentiation. HPV proteins activate DNA damage repair pathways by inducing high numbers of DNA breaks in both viral and cellular DNAs. This activation is required for HPV genome replication. TOP2β is a type II topoisomerase that induces double-strand DNA breaks at topologically associated domains (TADS) to relieve torsional stress arising during transcription or replication. Our studies demonstrate that TOP2β levels are increased in HPV-positive cells and that this is required for HPV replication. Importantly, our studies further show that knockdown of TOP2β reduces the number of breaks by over 50% in HPV-positive cells and that this correlates with substantially impaired activation of DNA repair pathways. This study identifies a critical mechanism by which HPV replication is regulated by the topoisomerase TOP2β through DNA break formation.
Topics: Cells, Cultured; DNA Breaks, Double-Stranded; DNA Topoisomerases, Type II; Foreskin; Gene Expression Regulation; Host-Pathogen Interactions; Humans; Keratinocytes; Male; Papillomaviridae; Virus Replication
PubMed: 33563836
DOI: 10.1128/mBio.00005-21 -
Mutation Research. Genetic Toxicology... Jan 2020Bioflavonoids have a similar chemical structure to etoposide, the well-characterized topoisomerase II (Top2) poison, and evidence shows that they also induce DNA...
Bioflavonoids have a similar chemical structure to etoposide, the well-characterized topoisomerase II (Top2) poison, and evidence shows that they also induce DNA double-strand breaks (DSBs) and promote genome rearrangements. The purpose of this study was to determine the kinetics of bioflavonoid-induced DSB appearance and repair, and their dependence on Top2. Cells were exposed to bioflavonoids individually or in combination in the presence or absence of the Top2 catalytic inhibitor dexrazoxane. The kinetics of appearance and repair of γH2AX foci were measured. In addition, the frequency of resultant MLL-AF9 breakpoint cluster region translocations was determined. Bioflavonoids readily induced the appearance of γH2AX foci, but bioflavonoid combinations did not act additively or synergistically to promote DSBs. Myricetin-induced DSBs were mostly reduced by dexrazoxane, while genistein and quercetin-induced DSBs were only partially, but significantly, reduced. By contrast, luteolin and kaempferol-induced DSBs increased with dexrazoxane pre-treatment. Sensitivity to Top2 inhibition correlated with a significant reduction of bioflavonoid-induced MLL-AF9 translocations. These data demonstrate that myricetin, genistein, and quercetin act most similar to etoposide although with varying Top2-dependence. By contrast, luteolin and kaempferol have distinct kinetics that are mostly Top2-independent. These findings have implications for understanding the mechanisms of bioflavonoid activity and the potential of individual bioflavonoids to promote chromosomal translocations. Further, they provide direct evidence that specific Top2 inhibitors or targeted drugs could be developed that possess less leukemic potential or suppress chromosomal translocations associated with therapy-related and infant leukemias.
Topics: Animals; Cell Line; Chromosome Breakpoints; Chromosomes, Mammalian; DNA; DNA Breaks, Double-Stranded; DNA Repair; DNA Topoisomerases, Type II; Dexrazoxane; Etoposide; Flavonoids; Genistein; Histones; Kaempferols; Luteolin; Mice; Mouse Embryonic Stem Cells; Quercetin; Topoisomerase II Inhibitors; Translocation, Genetic
PubMed: 32087851
DOI: 10.1016/j.mrgentox.2020.503144 -
Molecules (Basel, Switzerland) Jan 2021Pyrimido-pyrimidine derivatives have been developed as rigid merbarone analogues. In a previous study, these compounds showed potent antiproliferative activity and...
Pyrimido-pyrimidine derivatives have been developed as rigid merbarone analogues. In a previous study, these compounds showed potent antiproliferative activity and efficiently inhibited topoisomerase IIα. To further extend the structure-activity relationships on pyrimido-pyrimidines, a novel series of analogues was synthesized by a two-step procedure. Analogues - bear small alky groups at positions 1 and 3 of the pyrimido-pyrimidine scaffold whereas at position 6a (4-chloro)phenyl substituent was inserted. The basic side chains introduced at position 7 were selected on the basis of the previously developed structure-activity relationships. The antiproliferative activity of the novel compounds proved to be affected by both the nature of the basic side chain and the substituents on the pyrimido-pyrimidine moiety. Derivatives and were identified as the most promising molecules still showing reduced antiproliferative activity in comparison with the previously prepared pyrimido-pyrimidine analogues. In topoisomerase IIα- docking complex, the ligand would poorly interact with the enzyme and assume a different orientation in comparison with bioactive conformation.
Topics: Antineoplastic Agents; Cell Proliferation; DNA Topoisomerases, Type II; Female; Humans; MCF-7 Cells; Molecular Docking Simulation; Neoplasm Proteins; Neoplasms; Poly-ADP-Ribose Binding Proteins; Thiobarbiturates; Topoisomerase II Inhibitors
PubMed: 33494519
DOI: 10.3390/molecules26030557 -
Human Genetics Sep 2023Mutations in TDP2, encoding tyrosyl-DNA phosphodiesterase 2, have been associated with a syndromal form of autosomal recessive spinocerebellar ataxia, type 23 (SCAR23)....
Mutations in TDP2, encoding tyrosyl-DNA phosphodiesterase 2, have been associated with a syndromal form of autosomal recessive spinocerebellar ataxia, type 23 (SCAR23). This is a very rare and progressive neurodegenerative disorder described in only nine patients to date, and caused by splice site or nonsense mutations that result in greatly reduced or absent TDP2 protein. TDP2 is required for the rapid repair of DNA double-strand breaks induced by abortive DNA topoisomerase II (TOP2) activity, important for genetic stability in post-mitotic cells such as neurons. Here, we describe a sibship that is homozygous for the first TDP2 missense mutation (p.Glu152Lys) and which presents with clinical features overlapping both SCAR23 and Fanconi anemia (FA). We show that in contrast to previously reported SCAR23 patients, fibroblasts derived from the current patient retain significant levels of TDP2 protein. However, this protein is catalytically inactive, resulting in reduced rates of repair of TOP2-induced DNA double-strand breaks and cellular hypersensitivity to the TOP2 poison, etoposide. The TDP2-mutated patient-derived fibroblasts do not display increased chromosome breakage following treatment with DNA crosslinking agents, but both TDP2-mutated and FA cells exhibit increased chromosome breakage in response to etoposide. This suggests that the FA pathway is required in response to TOP2-induced DNA lesions, providing a possible explanation for the clinical overlap between FA and the current TDP2-mutated patients. When reviewing the relatively small number of patients with SCAR23 that have been reported, it is clear that the phenotype of such patients can extend beyond neurological features, indicating that the TDP2 protein influences not only neural homeostasis but also other tissues as well.
Topics: Humans; DNA-Binding Proteins; Etoposide; Fanconi Anemia; Chromosome Breakage; Siblings; Mutation, Missense; Phosphoric Diester Hydrolases; DNA Topoisomerases, Type II; DNA
PubMed: 37558815
DOI: 10.1007/s00439-023-02589-3 -
The Journal of Cell Biology Nov 2023In response to chromatin bridges, the abscission checkpoint delays completion of cytokinesis to prevent chromosome breakage or tetraploidization. Here, we show that...
In response to chromatin bridges, the abscission checkpoint delays completion of cytokinesis to prevent chromosome breakage or tetraploidization. Here, we show that spontaneous or replication stress-induced chromatin bridges exhibit "knots" of catenated and overtwisted DNA next to the midbody. Topoisomerase IIα (Top2α) forms abortive Top2-DNA cleavage complexes (Top2ccs) on DNA knots; furthermore, impaired Top2α-DNA cleavage activity correlates with chromatin bridge breakage in cytokinesis. Proteasomal degradation of Top2ccs is required for Rad17 localization to Top2-generated double-strand DNA ends on DNA knots; in turn, Rad17 promotes local recruitment of the MRN complex and downstream ATM-Chk2-INCENP signaling to delay abscission and prevent chromatin breakage. In contrast, dicentric chromosomes that do not exhibit knotted DNA fail to activate the abscission checkpoint in human cells. These findings are the first to describe a mechanism by which the abscission checkpoint detects chromatin bridges, through generation of abortive Top2ccs on DNA knots, to preserve genome integrity.
Topics: Humans; Cell Cycle Proteins; Cell Nucleus; Chromatin; Chromosome Breakage; Cytokinesis; DNA; Cell Cycle Checkpoints; DNA Topoisomerases, Type II
PubMed: 37638884
DOI: 10.1083/jcb.202303123 -
Open Biology Jan 2023The () gene is frequently rearranged in childhood and adult acute leukaemia (AL) and in secondary leukaemias occurring after therapy with DNA topoisomerase targeting... (Review)
Review
The () gene is frequently rearranged in childhood and adult acute leukaemia (AL) and in secondary leukaemias occurring after therapy with DNA topoisomerase targeting anti-cancer agents such as etoposide (t-AL). chromosome translocation break sites in AL patients fall within an 8 kb breakpoint cluster region (BCR). Furthermore, break sites in t-AL frequently occur in a much smaller region, or hotspot, towards the 3' end of the BCR, close to the intron 11/exon 12 boundary. These findings have prompted considerable effort to uncover mechanisms behind the apparent fragility of the BCR and particularly the t-AL hotspot. Recent genome-wide analyses have demonstrated etoposide-induced DNA cleavage within the BCR, and it is tempting to conclude that this cleavage explains the distribution of translocation break sites in t-AL. However, the t-AL hotspot and the centre of the observed preferential DNA cleavage are offset by over 250 nucleotides, suggesting additional factors contribute to the distribution of t-AL break sites. We review these recent genomic datasets along with older experimental results, analysis of TOP2 DNA cleavage site preferences and DNA secondary structure features that may lead to break site selection in t-AL translocations.
Topics: Humans; DNA; DNA Topoisomerases, Type II; Etoposide; Genome-Wide Association Study; Leukemia; Translocation, Genetic; Histone-Lysine N-Methyltransferase; Myeloid-Lymphoid Leukemia Protein
PubMed: 36629017
DOI: 10.1098/rsob.220232 -
Molecular Biology and Evolution Nov 2022Type II DNA topoisomerases regulate topology by double-stranded DNA cleavage and ligation. The TopoVI family of DNA topoisomerase, first identified and biochemically...
Type II DNA topoisomerases regulate topology by double-stranded DNA cleavage and ligation. The TopoVI family of DNA topoisomerase, first identified and biochemically characterized in Archaea, represents, with TopoVIII and mini-A, the type IIB family. TopoVI has several intriguing features in terms of function and evolution. TopoVI has been identified in some eukaryotes, and a global view is lacking to understand its evolutionary pattern. In addition, in eukaryotes, the two TopoVI subunits (TopoVIA and TopoVIB) have been duplicated and have evolved to give rise to Spo11 and TopoVIBL, forming TopoVI-like (TopoVIL), a complex essential for generating DNA breaks that initiate homologous recombination during meiosis. TopoVIL is essential for sexual reproduction. How the TopoVI subunits have evolved to ensure this meiotic function is unclear. Here, we investigated the phylogenetic conservation of TopoVI and TopoVIL. We demonstrate that BIN4 and RHL1, potentially interacting with TopoVIB, have co-evolved with TopoVI. Based on model structures, this observation supports the hypothesis for a role of TopoVI in decatenation of replicated chromatids and predicts that in eukaryotes the TopoVI catalytic complex includes BIN4 and RHL1. For TopoVIL, the phylogenetic analysis of Spo11, which is highly conserved among Eukarya, highlighted a eukaryal-specific N-terminal domain that may be important for its regulation. Conversely, TopoVIBL was poorly conserved, giving rise to ATP hydrolysis-mutated or -truncated protein variants, or was undetected in some species. This remarkable plasticity of TopoVIBL provides important information for the activity and function of TopoVIL during meiosis.
Topics: Phylogeny; Amino Acid Sequence; DNA Topoisomerases, Type II; Archaeal Proteins; Meiosis; Eukaryota
PubMed: 36256608
DOI: 10.1093/molbev/msac227 -
ACS Infectious Diseases Apr 2024Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone... (Review)
Review
Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone antibacterials. These drugs act by stabilizing gyrase/topoisomerase IV-generated DNA strand breaks and by robbing the cell of the catalytic activities of these essential enzymes. Since their clinical approval in the mid-1980s, fluoroquinolones have been used to treat a broad spectrum of infectious diseases and are listed among the five "highest priority" critically important antimicrobial classes by the World Health Organization. Unfortunately, the widespread use of fluoroquinolones has been accompanied by a rise in target-mediated resistance caused by specific mutations in gyrase and topoisomerase IV, which has curtailed the medical efficacy of this drug class. As a result, efforts are underway to identify novel antibacterials that target the bacterial type II topoisomerases. Several new classes of gyrase/topoisomerase IV-targeted antibacterials have emerged, including novel bacterial topoisomerase inhibitors, gyrase inhibitors, triazaacenaphthylenes, spiropyrimidinetriones, and thiophenes. Phase III clinical trials that utilized two members of these classes, gepotidacin (triazaacenaphthylene) and zoliflodacin (spiropyrimidinetrione), have been completed with positive outcomes, underscoring the potential of these compounds to become the first new classes of antibacterials introduced into the clinic in decades. Because gyrase and topoisomerase IV are validated targets for established and emerging antibacterials, this review will describe the catalytic mechanism and cellular activities of the bacterial type II topoisomerases, their interactions with fluoroquinolones, the mechanism of target-mediated fluoroquinolone resistance, and the actions of novel antibacterials against wild-type and fluoroquinolone-resistant gyrase and topoisomerase IV.
Topics: DNA Topoisomerase IV; Fluoroquinolones; DNA Gyrase; Topoisomerase II Inhibitors; Anti-Bacterial Agents; DNA; Mycobacterium tuberculosis
PubMed: 38564341
DOI: 10.1021/acsinfecdis.4c00128 -
Nature Jul 2014Spatial patterning is a ubiquitous feature of biological systems. Meiotic crossovers provide an interesting example, defined by the classic phenomenon of crossover...
Spatial patterning is a ubiquitous feature of biological systems. Meiotic crossovers provide an interesting example, defined by the classic phenomenon of crossover interference. Here we identify a molecular pathway for interference by analysing crossover patterns in budding yeast. Topoisomerase II plays a central role, thus identifying a new function for this critical molecule. SUMOylation (of topoisomerase II and axis component Red1) and ubiquitin-mediated removal of SUMOylated proteins are also required. The findings support the hypothesis that crossover interference involves accumulation, relief and redistribution of mechanical stress along the protein/DNA meshwork of meiotic chromosome axes, with topoisomerase II required to adjust spatial relationships among DNA segments.
Topics: Chromosomes, Fungal; Crossing Over, Genetic; DNA Topoisomerases, Type II; Meiosis; Mutation; Protein Processing, Post-Translational; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sumoylation
PubMed: 25043020
DOI: 10.1038/nature13442