Maleimide Is a Potent Inhibitor of Topoisomerase II in Vitro and in Vivo: A New Mode of Catalytic Inhibition

2002 ◽  
Vol 61 (5) ◽  
pp. 1235-1243 ◽  
Author(s):  
Lars H. Jensen ◽  
Axelle Renodon-Corniere ◽  
Irene Wessel ◽  
Seppo W. Langer ◽  
Birgitte Søkilde ◽  
...  
Keyword(s):  
Topoisomerase Ii ◽  
Potent Inhibitor

The in vivo distribution and dynamics of DNA topoisomerase II in Drosophila embryonic nuclei and chromosomes

1993 ◽  
Vol 51 ◽  
pp. 74-75
Author(s):  
Jason R. Swedlow ◽  
Neil Osheroff ◽  
Tim Karr ◽  
John W. Sedat ◽  
David A. Agard
Keyword(s):  
Topoisomerase Ii ◽  
Biochemical Characterization ◽  
Developmental Cycle ◽  
Dna Topoisomerase Ii ◽  
Chromosomal Distribution ◽  
Dna Topoisomerase ◽  
Ideal System ◽  
Dnase Treatment

DNA topoisomerase II is an ATP-dependent double-stranded DNA strand-passing enzyme that is necessary for full condensation of chromosomes and for complete segregation of sister chromatids at mitosis in vivo and in vitro. Biochemical characterization of chromosomes or nuclei after extraction with high-salt or detergents and DNAse treatment showed that topoisomerase II was a major component of this remnant, termed the chromosome scaffold. The scaffold has been hypothesized to be the structural backbone of the chromosome, so the localization of topoisomerase II to die scaffold suggested that the enzyme might play a structural role in the chromosome. However, topoisomerase II has not been studied in nuclei or chromosomes in vivo. We have monitored the chromosomal distribution of topoisomerase II in vivo during mitosis in the Drosophila embryo. This embryo forms a multi-nucleated syncytial blastoderm early in its developmental cycle. During this time, the embryonic nuclei synchronously progress through 13 mitotic cycles, so this is an ideal system to follow nuclear and chromosomal dynamics.

scholarly journals CHIR-124, a Novel Potent Inhibitor of Chk1, Potentiates the Cytotoxicity of Topoisomerase I Poisons In vitro and In vivo

2007 ◽  
Vol 13 (2) ◽  
pp. 591-602 ◽  
Author(s):  
Archie N. Tse ◽  
Katherine G. Rendahl ◽  
Tahir Sheikh ◽  
Haider Cheema ◽  
Kim Aardalen ◽  
...  
Keyword(s):  
Topoisomerase I ◽  
Potent Inhibitor

The C-terminal domain of Saccharomyces cerevisiae DNA topoisomerase II

1994 ◽  
Vol 14 (5) ◽  
pp. 3197-3207
Author(s):  
P R Caron ◽  
P Watt ◽  
J C Wang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Localization ◽  
Topoisomerase Ii ◽  
Dna Topoisomerase Ii ◽  
Dna Topoisomerase ◽  
Mutant Proteins ◽  
Terminal Domain ◽  
Catalytically Active

A set of carboxy-terminal deletion mutants of Saccharomyces cerevisiae DNA topoisomerase II were constructed for studying the functions of the carboxyl domain in vitro and in vivo. The wild-type yeast enzyme is a homodimer with 1,429 amino acid residues in each of the two polypeptides; truncation of the C terminus to Ile-1220 has little effect on the function of the enzyme in vitro or in vivo, whereas truncations extending beyond Gln-1138 yield completely inactive proteins. Several mutant enzymes with C termini in between these two residues were found to be catalytically active but unable to complement a top2-4 temperature-sensitive mutation. Immunomicroscopy results suggest that the removal of a nuclear localization signal in the C-terminal domain is likely to contribute to the physiological dysfunction of these proteins; the ability of these mutant proteins to relax supercoiled DNA in vivo shows, however, that at least some of the mutant proteins are present in the nuclei in a catalytically active form. In contrast to the ability of the catalytically active mutant proteins to relax supercoiled intracellular DNA, all mutants that do not complement the temperature-dependent lethality and high frequency of chromosomal nondisjunction of top2-4 were found to lack decatenation activity in vivo. The plausible roles of the DNA topoisomerase II C-terminal domain, in addition to providing a signal for nuclear localization, are discussed in the light of these results.

A highly potent inhibitor of cathepsin K (relacatib) reduces biomarkers of bone resorption both in vitro and in an acute model of elevated bone turnover in vivo in monkeys

Bone ◽  
2007 ◽  
Vol 40 (1) ◽  
pp. 122-131 ◽  
Author(s):  
S. Kumar ◽  
L. Dare ◽  
J.A. Vasko-Moser ◽  
I.E. James ◽  
S.M. Blake ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Turnover ◽  
Potent Inhibitor ◽  
Cathepsin K

Mitochondrial topoisomerase II activity is essential for kinetoplast DNA minicircle segregation

1994 ◽  
Vol 14 (6) ◽  
pp. 3660-3667
Author(s):  
T A Shapiro
Keyword(s):  
Replication Fork ◽  
Topoisomerase Ii ◽  
Potent Inhibitor ◽  
Late Replication ◽  
Kinetoplast Dna ◽  
Two Dimensional Gel Electrophoresis ◽  
Trypanosoma Equiperdum ◽  
Replication Intermediates ◽  
Novel Structures

Etoposide, a nonintercalating antitumor drug, is a potent inhibitor of topoisomerase II activity. When Trypanosoma equiperdum is treated with etoposide, cleavable complexes are stabilized between topoisomerase II and kinetoplast DNA minicircles, a component of trypanosome mitochondrial DNA (T. A. Shapiro, V. A. Klein, and P. T. Englund, J. Biol. Chem. 264:4173-4178, 1989). Etoposide also promotes the time-dependent accumulation of small minicircle catenanes. These catenanes are radiolabeled in vivo with [3H]thymidine. Dimers are most abundant, but novel structures containing up to five noncovalently closed minicircles are detectable. Analysis by two-dimensional gel electrophoresis and electron microscopy indicates that dimers joined by up to six interlocks are late replication intermediates that accumulate when topoisomerase II activity is blocked. The requirement for topoisomerase II is particularly interesting because minicircles do not share the features postulated to make this enzyme essential in other systems: for minicircles, the replication fork is unidirectional, access to the DNA is not blocked by nucleosomes, and daughter circles are extensively nicked and (or) gapped.

Consequences of topoisomerase II inhibition in early embryogenesis of Drosophila revealed by in vivo confocal laser scanning microscopy

1993 ◽  
Vol 104 (4) ◽  
pp. 1175-1185 ◽  
Author(s):  
P. Buchenau ◽  
H. Saumweber ◽  
D.J. Arndt-Jovin
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Topoisomerase Ii ◽  
Metaphase Plate ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser

The regulation of DNA topology by topoisomerase II from Drosophila melanogaster has been studied extensively by biochemical methods but little is known about its roles in vivo. We have performed experiments on the inhibition of topoisomerase II in living Drosophila blastoderm embryos. We show that the enzymatic activity can be specifically disrupted by microinjection of antitopoisomerase II antibodies as well as the epipodophyllotoxin VM26, a known inhibitor of topoisomerase II in vitro. By labeling the chromatin of live embryos with tetramethylrhodamine-coupled histones, the effects of inhibition on nuclear morphology and behaviour was followed in vivo using confocal laser scanning microscopy. Both the antibodies and the drug prevented or hindered the segregation of chromatin daughter sets at the anaphase stage of mitosis. In addition, high concentrations of inhibitor interfered with the condensation of chromatin and its proper arrangement into the metaphase plate. The observed effects yielded non-functional nuclei, which were drawn into the inner yolk mass of the embryo. Concurrently, undamaged nuclei surrounding the affected region underwent compensatory division, leading to the restoration of the nuclear population, and thereby demonstrating the regulative capacity of Drosophila blastoderm embryos.

Monascin and monascinol, azaphilonoid pigments from Mortierella polycephala AM1: in silico and in vitro targeting of the angiogenic VEGFR2 kinase

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed Shaaban ◽  
Mohammad Magdy El-Metwally ◽  
Amal A. I. Mekawey ◽  
Ahmed B. Abdelwahab ◽  
Maha M. Soltan
Keyword(s):  
In Silico ◽  
Topoisomerase Ii ◽  
Potent Inhibitor ◽  
Bioactive Metabolites ◽  
Cytotoxic Activities ◽  
Feather Waste ◽  
Biological Target ◽  
Topo Ii ◽  
Poultry Feather

Abstract The fungus, Mortierella polycephala is one of the most productive sources of anticancer bioactive compounds namely those of pigment nature. During our investigation of the produced bioactive metabolites by the terrestrial M. polycephala AM1 isolated from Egyptian poultry feather waste, two main azaphilonoid pigments, monascin (1) and monascinol (2) were obtained as major products; their structures were identified by 1D (1H&13C) and 2D (1H–1H COSY, HMBC) NMR and HRESI-MS spectroscopic data. Biologically, cytotoxic activities of these compounds were broadly studied compared with the fungal extract. To predict the biological target for the presumed antitumor activity, an in silico study was run toward three proteins, topoisomerase IIα, topoisomerase IIβ, and VEGFR2 kinase. Monascinol (2) was expected to be moderately active against VEGFR2 kinase without any anticipated inhibition toward topo II isoforms. The in vitro study confirmed the docked investigation consistently and introduced monascinol (2) rather than its counterpart (1) as a potent inhibitor to the tested VEGFR2 kinase. Taxonomically, the fungus was identified using morphological and genetic assessments.

4-Methoxydalbergione is a potent inhibitor of human astroglioma U87 cells in vitro and in vivo

2020 ◽  
Author(s):  
Ran Li ◽  
Chang-qiong Xu ◽  
Jian-xin Shen ◽  
Qiu-yun Ren ◽  
Di-ling Chen ◽  
...  
Keyword(s):  
Potent Inhibitor ◽  
U87 Cells

scholarly journals Regulation of peripheral lipogenesis by glucagon. Inability of the hormone to inhibit lipogenesis in rat mammary acini in vitro in the presence or absence of agents which alter its effects on adipocytes

1984 ◽  
Vol 217 (3) ◽  
pp. 743-749 ◽  
Author(s):  
N A Robson ◽  
R A Clegg ◽  
V A Zammit
Keyword(s):  
Concentration Ratio ◽  
Response Curve ◽  
Potent Inhibitor ◽  
Specific Binding ◽  
Insulin Dose ◽  
Mammary Glands ◽  
Key Steps ◽  
Glucagon Concentration

The rate of lipogenesis in acini isolated from mammary glands of mid-lactating rats was studied by measuring the rate of incorporation of 3H from 3H2O into total lipid and fatty acids, with glucose as substrate. Glucagon did not affect the rate of lipogenesis in acini. Glucagon did not antagonize the maximal stimulatory effect of insulin, nor did it alter the insulin dose-response curve. Theophylline, at concentrations up to 20 mM, was a potent inhibitor of lipogenesis in acini. Glucagon did not augment the degree of inhibition of lipogenesis induced by 5 mM-theophylline. The results suggest that mammary-gland acini do not respond to glucagon in vitro under conditions in which the hormone induces inhibition of lipogenesis (the present paper) and of individual key steps in the lipogenic pathway in adipocytes [Zammit & Corstorphine (1982) Biochem. J. 208, 783-788; Green (1983) Biochem. J. 212, 189-195]. In agreement with these observations, we could detect only a minimal degree of specific binding of 125I-labelled glucagon to acini which bound insulin normally. This difference in responsiveness of mammary and adipose cell preparations in vitro to glucagon suggests that the two tissues may be differentially responsive to changes in the circulating insulin/glucagon concentration ratio in vivo. The significance of these findings for the regulation of substrate utilization for lipogenesis in the two tissues during lactation is discussed.

scholarly journals Effect of etoposide on grass pea DNA topoisomerase II: an in silico, in vivo, and in vitro assessments

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Aveek Samanta ◽  
Tilak Raj Maity ◽  
Sudip Das ◽  
Animesh Kumar Datta ◽  
Siraj Datta
Keyword(s):  
In Silico ◽  
Topoisomerase Ii ◽  
Cost Effective ◽  
Colchicine Treatment ◽  
Grass Pea ◽  
Dna Topoisomerase ◽  
Ammonium Sulphate Precipitation ◽  
In Silico Study

Abstract Background Etoposide is one of the most potential anti-cancerous drugs that targets topoisomerase II (topoII) and inhibits its activity by ligation with the DNA molecule. Results In silico study confirmed that the etoposide-binding sites of topoII are conserved among the plants and human. The efficacy of the drug on plant system was initially assessed using germinated grass pea (Lathyrus sativus L.) seedlings (in vivo) in relation to radicle length and mitotic index. The callus system (in vitro) was also used to elucidate the effect of etoposide on callus growth kinetics. Furthermore, it was observed that etoposide able to inhibit the division of polyploid cells induced by colchicine treatment (0.5%, 8 h). To determine the molecular interaction, topoII was isolated from young grass pea leaves using polyethylene glycol fractionation and ammonium sulphate precipitation followed by column chromatography on CM-Sephadex (C-25). The plasmid linearization assays by isolated plant topoII in the presence of etoposide significantly revealed the functional similarity of plants and human topoII. Results indicated that the effect of etoposide on plant topoII is significant. Conclusions This study may pave the way to develop a plant-based assay system for screening the topoisomerase targeted anti-cancerous drugs, as it is convenient and cost-effective.

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