The Dihydropyridine Dexniguldipine Hydrochloride Inhibits Cleavage and Religation Reactions of Eukaryotic DNA Topoisomerase I

Straub, Tobias; Boesenberg, Charlotte; Gekeler, Volker; Boege, Fritz

doi:10.1021/bi970417q

Cited by 37 publications

(25 citation statements)

References 22 publications

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“…We show here that camptothecin further attenuates the slow fraction of nucleoplasmic topoisomerase I, which supports the above notion of this fraction being the one engaged in DNA turnover. At least in living cells, the drug does not immobilize topoisomerase I completely, which fits some previous biochemical data (19) showing that topoisomerase I⅐DNA intermediates stabilized by camptothecin have a comparatively short half-life (Ͻ1 min). Why does topoisomerase I disappear so rapidly from its favored nucleolar residence when camptothecin is present?…”

Section: Localization and Mobility Of Gfp-topoisomerase I In Living Csupporting

confidence: 89%

Changes in Mobility Account for Camptothecin-induced Subnuclear Relocation of Topoisomerase I

Christensen

Barthelmes

Feineis

et al. 2002

Journal of Biological Chemistry

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DNA topoisomerase I is a nucleolar protein, which relocates to the nucleoplasm in response to drugs stabilizing topoisomerase I⅐DNA intermediates (e.g. camptothecin). Here we demonstrate that this phenomenon is solely caused by the drug's impact on the interplay between mobility and localization of topoisomerase I in a living cell nucleus. We show by photobleaching of cells expressing biofluorescent topoisomerase I-chimera that the enzyme moves continuously between nucleoli and nucleoplasm. Complex kinetics of fluorescence recovery after photobleaching indicates that two enzyme fractions with different mobility coexist in nucleoli and nucleoplasm. However, the whole complement of topoisomerase I is in continuous flux between these compartments and nucleolar accumulation can plausibly explained by the enzyme's 2-fold lesser overall mobility in nucleoli versus nucleoplasm. Upon addition of camptothecin, topoisomerase I relocates within 30 s from the nucleoli to radial nucleoplasmic structures. At these sites, the enzyme becomes retarded in a dose-dependent manner. Inside nucleoli the mobility of topoisomerase I is much less affected by camptothecin. Thus, the enzyme's distribution equilibrium is shifted toward the nucleoplasm, which causes nucleolar delocalization. In general, topoisomerase I is an entirely mobile nuclear component, unlikely to require specific signaling for movements between nuclear compartments. DNA topoisomerase I changes the pitch of DNA helices by cutting one DNA strand and allowing passage of the complementary strand through the transient nick (1). One important role for this mechanism is the release of torsional stress created by DNA transcription. Thus, topoisomerase I activity is in principle required in the nucleoplasm for mRNA synthesis (2) and in the nucleolus for rRNA synthesis (3). However, the latter is considered the major working place of the enzyme, which has been recognized as a predominantly nucleolar protein (3, 4). Camptothecin and other agents stabilizing covalent topoisomerase I⅐DNA intermediates cause relocation of topoisomerase I from the nucleoli to the nucleoplasm (5). This was also observed with inhibitors of RNA synthesis prompting the conclusion that the phenomenon might be related to reduced activity of rRNA biosynthesis in the nucleolus (6). Alternatively, it has been proposed that camptothecin-induced conjugation of topoisomerase I with small ubiquitin-like modifiers might serve as a signal triggering translocation of topoisomerase I from the nucleoli to the nucleoplasm (7).Until now the dynamic properties of topoisomerase I in the nucleus or between nuclear compartments have not been assessed directly. Thus, it is not clear whether the enzyme is mobile or not, whether it resides in the nucleolus in a static manner and moves into the nucleoplasm in response to specific signals (as suggested in ref. 7) or whether it shuttles continuously between nucleolus and nucleoplasm. Consequently, it is also unclear as to what is the molecular event that leads to nucleolar del...

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Section: Localization and Mobility Of Gfp-topoisomerase I In Living Csupporting

confidence: 89%

Changes in Mobility Account for Camptothecin-induced Subnuclear Relocation of Topoisomerase I

Christensen

Barthelmes

Feineis

et al. 2002

Journal of Biological Chemistry

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“…We therefore believe that the sites of occupancy of the drugs and the incoming nucleophile (tyramine or the 5Ј-OH DNA end) are the same, partially overlapping or at least in close enough proximity to elicit mutual competition. Such a drug interaction mode with Flp is consistent with previously published results demonstrating that CPT inhibits topo I-mediated ligation in a competitive manner (31). Moreover, the similarity in the inhibition of Flp-mediated cleavage and ligation suggests that the two reactions are catalyzed by similar active site conformations.…”

Section: Cpt and Nsc-314622 Inhibit Flp Transesterification In A Compsupporting

confidence: 91%

Inhibition of Flp Recombinase by the Topoisomerase I-targeting Drugs, Camptothecin and NSC-314622

Frøhlich

Hansen

Lisby

et al. 2001

Journal of Biological Chemistry

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Recombinases of the -Int family and type IB topoisomerases act by introducing transient single strand breaks in DNA using chemically identical reaction schemes. Recent structural data have supported the relationship between the two enzyme groups by revealing considerable similarities in the architecture of their catalytic pockets. In this study we show that the Int-type recombinase Flp is inhibited by the two structurally unrelated topoisomerase I-directed anti-cancer drugs, camptothecin (CPT) and NSC-314622. The interaction of these drugs with topoisomerase I is very specific with several single amino acid substitutions conferring drug resistance to the enzyme. Thus, the observed interaction of CPT and NSC-314622 with Flp, which is comparable to their interaction with the cleavage complex formed by topoisomerase I, strongly supports a close mechanistic and evolutionary relationship between the two enzymes. The results suggest that Flp and other Int family recombinases may provide model systems for dissecting the molecular mechanisms of topoisomerase I-directed anti-cancer therapeutic agents. Members of the integrase (Int)1 family of site-specific recombinases (-integrase, P1 Cre recombinase, Escherichia coli XerC/XerD recombinase, Saccharomyces cerevisiae Flp, and Zygosaccharomyces rouxii R recombinases among several others) all carry out conservative site-specific recombination using a basic type IB topoisomerase reaction scheme (1, 2). In the first step of recombination, an active site tyrosine nucleophile attacks the target phosphodiester bond in DNA to generate a 3Ј-phosphotyrosyl linkage and a free 5Ј-hydroxyl group. In the second step leading to strand rejoining, the 5Ј-hydroxyl group is the nucleophile, and the 3Ј-phosphotyrosyl bond is its target.The nucleophilic attack is directed across partner substrates so that strand ligation occurs in the recombinant configuration, which is opposed to the typical type IB topoisomerase reaction in which ligation restores the original phosphodiester bond (3). However, the two ligation modes are not mutually exclusive, as evident from the fact that some Int recombinases can relax supercoiled DNA in vitro under certain conditions while some type IB topoisomerases can mediate recombination and resolution of Holliday junctions (4 -8). Recent structural data have further consolidated the relationship between the Int family recombinases and the type IB topoisomerases. Despite the lack of overall sequence homology between the two enzyme groups, the tertiary folds within the catalytic domains are strikingly similar between the Int-type recombinases, including Flp (9) and Cre (10), and eukaryotic topoisomerase I (topo I) (11)(12)(13)(14). Moreover, the critical catalytic moieties include two nearly identical tetrads, RHRH/W in the recombinases and RKRH in the topoisomerases, together with the invariant tyrosine nucleophile (1,11).In this study we have further probed the functional relationship between the Int family recombinase and type IB topoisomerase active sites by inves...

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“…The specific role of the bioactivity of pyridine ring has been recognized and the introduction of some pyridine analogs into the molecules of drugs could result in new compounds that have significant biological activity compared with the parent compounds Straub et al, 1997;Bolognese et al, 2002;Tiwari et al, 2002;Kuo et al, 2005). It was also reported that a diverse array of naturally occurring alkaloids in sponges exhibit potent bioactivities because of the presence of a pyridine moiety (Vincent et al, 1997;Gordon et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Design, synthesis, and biological evaluation of novel pyridine acid esters of podophyllotoxin and esters of 4′-demethylepipodophyllotoxin

Liu

Tian

2007

Med Chem Res

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Podophyllotoxin and related analogs present numerous challenges associated with optimal antitumor activity and severe unpredictable toxicity. In the course of our ongoing investigation of quantitative structure-activity relationships to find biorational antitumor drugs, two series of pyridine acid ester derivatives of podophyllotoxin and 4 0 -demethylepipodophyllotoxin have been prepared by reacting the corresponding pyridine acids with the hydroxyl group of podophyllotoxin and 4 0 -demethyl epipodophyllotoxin in the presence of dimethylaminopyridine (DMAP) and N,N-dicyclohexylcarbodiimde (DCC). The structures of the compounds were extensively characterized by using 1 H-nuclear magnetic resonance, mass spectroscopy, infrared, and elemental analysis and evaluated for their in vitro cytotoxicity on two neoplastic cell lines (P-388 murine leukemia, A-549 human lung carcinoma) using a MTT-based assay, the results indicated significantly higher efficacy of these compounds in comparison with the prototypical inhibitor etoposide. On the basis of the preliminary biological testing results, it suggested that the cytotoxic activity of OCH 3 at C-4 0 is more potent than that of its demethylated analogs and the podophyllotoxin substitution at C-4 may be optimal for synthesizing more potent cytotoxic compounds.

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The Dihydropyridine Dexniguldipine Hydrochloride Inhibits Cleavage and Religation Reactions of Eukaryotic DNA Topoisomerase I

Cited by 37 publications

References 22 publications

Changes in Mobility Account for Camptothecin-induced Subnuclear Relocation of Topoisomerase I

Changes in Mobility Account for Camptothecin-induced Subnuclear Relocation of Topoisomerase I

Inhibition of Flp Recombinase by the Topoisomerase I-targeting Drugs, Camptothecin and NSC-314622

Design, synthesis, and biological evaluation of novel pyridine acid esters of podophyllotoxin and esters of 4′-demethylepipodophyllotoxin

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