Anthracyclines, such as doxorubicin (adriamycin), daunorubicin, or epirubicin, rank among the most effective agents in classical anticancer chemotherapy. However, cardiotoxicity remains the main limitation of their clinical use. Topoisomerase IIβ has recently been identified as a plausible target of anthracyclines in cardiomyocytes. We examined the putative topoisomerase IIβ selective agent XK469 as a potential cardioprotective and designed several new analogs. In our experiments, XK469 inhibited both topoisomerase isoforms (α and β) and did not induce topoisomerase II covalent complexes in isolated cardiomyocytes and HL-60, but induced proteasomal degradation of topoisomerase II in these cell types. The cardioprotective potential of XK469 was studied on rat neonatal cardiomyocytes, where dexrazoxane (ICRF-187), the only clinically approved cardioprotective, was effective. Initially, XK469 prevented daunorubicin-induced toxicity and p53 phosphorylation in cardiomyocytes. However, it only partially prevented the phosphorylation of H2AX and did not affect DNA damage measured by Comet Assay. It also did not compromise the daunorubicin antiproliferative effect in HL-60 leukemic cells. When administered to rabbits to evaluate its cardioprotective potential in vivo, XK469 failed to prevent the daunorubicin-induced cardiac toxicity in either acute or chronic settings. In the following in vitro analysis, we found that prolonged and continuous exposure of rat neonatal cardiomyocytes to XK469 led to significant toxicity. In conclusion, this study provides important evidence on the effects of XK469 and its combination with daunorubicin in clinically relevant doses in cardiomyocytes. Despite its promising characteristics, long-term treatments and in vivo experiments have not confirmed its cardioprotective potential.

• MeSH
• antibiotika antitumorózní toxicita   MeSH
• antracykliny * toxicita   terapeutické užití   MeSH
• chinoxaliny * MeSH
• daunomycin toxicita   terapeutické užití   MeSH
• DNA-topoisomerasy typu II metabolismus   terapeutické užití   MeSH
• doxorubicin toxicita   MeSH
• inhibitory topoisomerasy II * toxicita   terapeutické užití   MeSH
• kardiotoxicita MeSH
• králíci MeSH
• krysa rodu rattus MeSH
• poškození DNA MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Klebsiella pneumoniae is an important cause of nosocomial infections and displays increasing resistance to fluoroquinolones (FQ). This study surveyed the mechanisms of FQ resistance and molecular typing of K. pneumoniae isolates from intensive care units patients in Tehran, Iran. A total of 48 ciprofloxacin (CIP) resistant K. pneumoniae isolates from urine samples were included in this study. Broth microdilution assays revealed high-level CIP resistance (MIC > 32 μg/mL) in 31.25% of the isolates. Plasmid-mediated quinolone resistance genes were detected in 41 (85.4%) isolates. Among which, qnrS (41.67%) was the most prevalent followed by qnrD (35.42%), qnrB (27.1%), qnrA (25%), qepA (22.9%), aac(6')-Ib-cr (20.83%), and qnrC (6.25%). Target site mutations (gyrA and parC) were assessed using PCR and sequencing on all isolates. A single mutation in gyrA (S83I) was found in 13 (27.1%) isolates and two isolates harbored six simultaneous mutations. Fourteen isolates (29.2%) had mutations in parC and S129A and A141V mutations were the most prevalent. Real time PCR showed an increase in the expression level of acrB and oqxB efflux genes in 68.75 and 29.16% isolates, respectively. Enterobacterial repetitive intergenic consensus (ERIC)-PCR revealed 14 genotypes and 11 of them were classified by multilocus sequence typing (MLST) into 11 different sequence types belonging to seven clonal complexes and two singletons, most of them have not been reported in Iran yet. We are concerned about the spread of these clones throughout our country. Most FQ resistance mechanisms were detected among our isolates. However, target site mutation had the greatest effect on CIP resistance among our isolates.

• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální léková rezistence genetika   MeSH
• ciprofloxacin * farmakologie   MeSH
• DNA gyráza genetika   MeSH
• fluorochinolony * farmakologie   MeSH
• Klebsiella pneumoniae genetika   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• molekulární epidemiologie MeSH
• multilokusová sekvenční typizace MeSH
• plazmidy MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Írán MeSH

The potential of acridines (amsacrine) as a topoisomerase II inhibitor or poison was first discovered in 1984, and since then, a considerable number of acridine derivatives have been tested as topoisomerase inhibitors/poisons, containing different substituents on the acridine chromophore. This review will discuss a series of studies published over the course of the last decade, which have investigated various novel acridine derivatives against topoisomerase II activity.

• MeSH
• akridiny farmakologie   MeSH
• amsakrin MeSH
• antitumorózní látky * farmakologie   MeSH
• DNA-topoisomerasy typu II MeSH
• jedy * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

BACKGROUND: Anthracycline-induced heart failure has been traditionally attributed to direct iron-catalyzed oxidative damage. Dexrazoxane (DEX)-the only drug approved for its prevention-has been believed to protect the heart via its iron-chelating metabolite ADR-925. However, direct evidence is lacking, and recently proposed TOP2B (topoisomerase II beta) hypothesis challenged the original concept. METHODS: Pharmacokinetically guided study of the cardioprotective effects of clinically used DEX and its chelating metabolite ADR-925 (administered exogenously) was performed together with mechanistic experiments. The cardiotoxicity was induced by daunorubicin in neonatal ventricular cardiomyocytes in vitro and in a chronic rabbit model in vivo (n=50). RESULTS: Intracellular concentrations of ADR-925 in neonatal ventricular cardiomyocytes and rabbit hearts after treatment with exogenous ADR-925 were similar or exceeded those observed after treatment with the parent DEX. However, ADR-925 did not protect neonatal ventricular cardiomyocytes against anthracycline toxicity, whereas DEX exhibited significant protective effects (10-100 µmol/L; P<0.001). Unlike DEX, ADR-925 also had no significant impact on daunorubicin-induced mortality, blood congestion, and biochemical and functional markers of cardiac dysfunction in vivo (eg, end point left ventricular fractional shortening was 32.3±14.7%, 33.5±4.8%, 42.7±1.0%, and 41.5±1.1% for the daunorubicin, ADR-925 [120 mg/kg]+daunorubicin, DEX [60 mg/kg]+daunorubicin, and control groups, respectively; P<0.05). DEX, but not ADR-925, inhibited and depleted TOP2B and prevented daunorubicin-induced genotoxic damage. TOP2B dependency of the cardioprotective effects was probed and supported by experiments with diastereomers of a new DEX derivative. CONCLUSIONS: This study strongly supports a new mechanistic paradigm that attributes clinically effective cardioprotection against anthracycline cardiotoxicity to interactions with TOP2B but not metal chelation and protection against direct oxidative damage.

• MeSH
• antibiotika antitumorózní škodlivé účinky   farmakologie   MeSH
• antracykliny škodlivé účinky   farmakologie   MeSH
• daunomycin metabolismus   farmakologie   MeSH
• dexrazoxan škodlivé účinky   farmakologie   MeSH
• DNA-topoisomerasy typu II škodlivé účinky   metabolismus   MeSH
• inhibitory topoisomerasy II metabolismus   MeSH
• kardiomyocyty účinky léků   metabolismus   MeSH
• kardiotoxicita farmakoterapie   metabolismus   prevence a kontrola   MeSH
• lidé MeSH
• nemoci srdce farmakoterapie   MeSH
• oxidační stres účinky léků   MeSH
• srdeční selhání farmakoterapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cardioprotective activity of dexrazoxane (ICRF-187), the only clinically approved drug against anthracycline-induced cardiotoxicity, has traditionally been attributed to its iron-chelating metabolite. However, recent experimental evidence suggested that the inhibition and/or depletion of topoisomerase IIβ (TOP2B) by dexrazoxane could be cardioprotective. Hence, we evaluated a series of dexrazoxane analogues and found that their cardioprotective activity strongly correlated with their interaction with TOP2B in cardiomyocytes, but was independent of their iron chelation ability. Very tight structure-activity relationships were demonstrated on stereoisomeric forms of 4,4'-(butane-2,3-diyl)bis(piperazine-2,6-dione). In contrast to its rac-form 12, meso-derivative 11 (ICRF-193) showed a favorable binding mode to topoisomerase II in silico, inhibited and depleted TOP2B in cardiomyocytes more efficiently than dexrazoxane, and showed the highest cardioprotective efficiency. Importantly, the observed ICRF-193 cardioprotection did not interfere with the antiproliferative activity of anthracycline. Hence, this study identifies ICRF-193 as the new lead compound in the development of efficient cardioprotective agents.

• MeSH
• daunomycin toxicita   MeSH
• DNA-topoisomerasy typu II metabolismus   MeSH
• inhibitory topoisomerasy II chemická syntéza   metabolismus   terapeutické užití   MeSH
• kardiomyocyty účinky léků   MeSH
• kardiotonika chemická syntéza   metabolismus   terapeutické užití   MeSH
• kardiotoxicita farmakoterapie   MeSH
• lidé MeSH
• molekulární struktura MeSH
• nádorové buněčné linie MeSH
• novorozená zvířata MeSH
• piperaziny chemická syntéza   metabolismus   terapeutické užití   MeSH
• potkani Wistar MeSH
• proliferace buněk účinky léků   MeSH
• Saccharomyces cerevisiae - proteiny metabolismus   MeSH
• Saccharomyces cerevisiae chemie   MeSH
• simulace molekulární dynamiky MeSH
• simulace molekulového dockingu MeSH
• vazba proteinů MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The bisdioxopiperazine topoisomerase IIβ inhibitor ICRF-193 has been previously identified as a more potent analog of dexrazoxane (ICRF-187), a drug used in clinical practice against anthracycline cardiotoxicity. However, the poor aqueous solubility of ICRF-193 has precluded its further in vivo development as a cardioprotective agent. To overcome this issue, water-soluble prodrugs of ICRF-193 were prepared, their abilities to release ICRF-193 were investigated using a novel UHPLC-MS/MS assay, and their cytoprotective effects against anthracycline cardiotoxicity were tested in vitro in neonatal ventricular cardiomyocytes (NVCMs). Based on the obtained results, the bis(2-aminoacetoxymethyl)-type prodrug GK-667 was selected for advanced investigations due to its straightforward synthesis, sufficient solubility, low cytotoxicity and favorable ICRF-193 release. Upon administration of GK-667 to NVCMs, the released ICRF-193 penetrated well into the cells, reached sufficient intracellular concentrations and provided effective cytoprotection against anthracycline toxicity. The pharmacokinetics of the prodrug, ICRF-193 and its rings-opened metabolite was estimated in vivo after administration of GK-667 to rabbits. The plasma concentrations of ICRF-193 reached were found to be adequate to achieve cardioprotective effects in vivo. Hence, GK-667 was demonstrated to be a pharmaceutically acceptable prodrug of ICRF-193 and a promising drug candidate for further evaluation as a potential cardioprotectant against chronic anthracycline toxicity.

• MeSH
• antracykliny škodlivé účinky   MeSH
• dexrazoxan chemie   farmakologie   MeSH
• diketopiperaziny chemie   farmakologie   MeSH
• DNA-topoisomerasy typu II metabolismus   MeSH
• inhibitory topoisomerasy II chemie   farmakologie   MeSH
• kardiomyocyty účinky léků   metabolismus   MeSH
• kardiotonika chemie   farmakologie   MeSH
• kardiotoxicita farmakoterapie   metabolismus   MeSH
• králíci MeSH
• piperazin chemie   farmakologie   MeSH
• prekurzory léčiv chemie   farmakologie   MeSH
• razoxan chemie   farmakologie   MeSH
• voda chemie   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A549 human lung carcinoma cell lines were treated with a series of new drugs with both tacrine and coumarin pharmacophores (derivatives 1a-2c) in order to test the compounds' ability to inhibit both cancer cell growth and topoisomerase I and II activity. The ability of human topoisomerase I (hTOPI) and II to relax supercoiled plasmid DNA in the presence of various concentrations of the tacrine-coumarin hybrid molecules was studied with agarose gel electrophoresis. The biological activities of the derivatives were studied using MTT assays, clonogenic assays, cell cycle analysis and quantification of cell number and viability. The content and localization of the derivatives in the cells were analysed using flow cytometry and confocal microscopy. All of the studied compounds were found to have inhibited topoisomerase I activity completely. The effect of the tacrine-coumarin hybrid compounds on cancer cells is likely to be dependent on the length of the chain between the tacrine and coumarin moieties (1c, 1d = tacrine-(CH2)8-9-coumarin). The most active of the tested compounds, derivatives 1c and 1d, both display longer chains.

• MeSH
• antitumorózní látky chemie   farmakologie   MeSH
• buňky A549 MeSH
• DNA-topoisomerasy I metabolismus   MeSH
• DNA-topoisomerasy typu II metabolismus   MeSH
• inhibitory topoisomerasy I chemie   farmakologie   MeSH
• inhibitory topoisomerasy II chemie   farmakologie   MeSH
• kumariny chemie   farmakologie   MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• molekulární struktura MeSH
• nádorové buňky kultivované MeSH
• proliferace buněk účinky léků   MeSH
• proteiny vázající poly-ADP-ribosu antagonisté a inhibitory   metabolismus   MeSH
• takrin chemie   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The importance of fluorescence light microscopy for understanding cellular and sub-cellular structures and functions is undeniable. However, the resolution is limited by light diffraction (~200-250 nm laterally, ~500-700 nm axially). Meanwhile, super-resolution microscopy, such as structured illumination microscopy (SIM), is being applied more and more to overcome this restriction. Instead, super-resolution by stimulated emission depletion (STED) microscopy achieving a resolution of ~50 nm laterally and ~130 nm axially has not yet frequently been applied in plant cell research due to the required specific sample preparation and stable dye staining. Single-molecule localization microscopy (SMLM) including photoactivated localization microscopy (PALM) has not yet been widely used, although this nanoscopic technique allows even the detection of single molecules. In this study, we compared protein imaging within metaphase chromosomes of barley via conventional wide-field and confocal microscopy, and the sub-diffraction methods SIM, STED, and SMLM. The chromosomes were labeled by DAPI (4',6-diamidino-2-phenylindol), a DNA-specific dye, and with antibodies against topoisomerase IIα (Topo II), a protein important for correct chromatin condensation. Compared to the diffraction-limited methods, the combination of the three different super-resolution imaging techniques delivered tremendous additional insights into the plant chromosome architecture through the achieved increased resolution.

• MeSH
• chromozomy rostlin chemie   genetika   metabolismus   MeSH
• DNA-topoisomerasy typu II metabolismus   MeSH
• fluorescenční barviva chemie   MeSH
• fluorescenční mikroskopie metody   MeSH
• indoly chemie   MeSH
• ječmen (rod) cytologie   genetika   MeSH
• konfokální mikroskopie metody   MeSH
• metafáze genetika   MeSH
• reprodukovatelnost výsledků MeSH
• zobrazení jednotlivé molekuly metody   MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

The rise in multidrug-resistant bacteria defines the need for identification of new antibacterial agents that are less prone to resistance acquisition. Compounds that simultaneously inhibit multiple bacterial targets are more likely to suppress the evolution of target-based resistance than monotargeting compounds. The structurally similar ATP binding sites of DNA gyrase and topoisomerase Ⅳ offer an opportunity to accomplish this goal. Here we present the design and structure-activity relationship analysis of balanced, low nanomolar inhibitors of bacterial DNA gyrase and topoisomerase IV that show potent antibacterial activities against the ESKAPE pathogens. For inhibitor 31c, a crystal structure in complex with Staphylococcus aureus DNA gyrase B was obtained that confirms the mode of action of these compounds. The best inhibitor, 31h, does not show any in vitro cytotoxicity and has excellent potency against Gram-positive (MICs: range, 0.0078-0.0625 μg/mL) and Gram-negative pathogens (MICs: range, 1-2 μg/mL). Furthermore, 31h inhibits GyrB mutants that can develop resistance to other drugs. Based on these data, we expect that structural derivatives of 31h will represent a step toward clinically efficacious multitargeting antimicrobials that are not impacted by existing antimicrobial resistance.

• MeSH
• adenosintrifosfát chemická syntéza   chemie   farmakologie   MeSH
• antibakteriální látky chemická syntéza   chemie   farmakologie   MeSH
• DNA gyráza metabolismus   MeSH
• DNA-topoisomerasa IV antagonisté a inhibitory   metabolismus   MeSH
• Escherichia coli účinky léků   enzymologie   patogenita   MeSH
• krystalografie rentgenová MeSH
• mikrobiální testy citlivosti MeSH
• molekulární struktura MeSH
• simulace molekulového dockingu MeSH
• Staphylococcus aureus účinky léků   enzymologie   patogenita   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH

A series of new 3,6,9-trisubstituted acridine derivatives with fluorine substituents on phenyl ring were synthesized and their interaction with calf thymus DNA was investigated. Analysis using UV-Vis absorbance spectra provided valuable information about the formation of the acridine-DNA complex. In addition, compounds 8b and 8d were found to display an increased binding affinity (K = 2.32 and 2.28 × 106 M-1, respectively). Topo I/II inhibition mode assays were also performed, and the results verify that the novel compounds display topoisomerase I and II inhibitory activity; compounds 8a, 8b and 8c completely inhibited topoisomerase I activity at a concentration of 60 × 10-6 M, but only compound 8d showed partial ability to inhibit topoisomerase II at concentrations of 30 and 50 × 10-6 M. The ability of the derivatives to impair cell proliferation was tested through an analysis of cell cycle distribution, quantification of cell number, viability studies, metabolic activity measurement and clonogenic assay. The content and localization of the derivatives in cells were analyzed using flow cytometry and fluorescence microscopy. The compounds 8b and 8d altered the physiochemical properties and improved antiproliferative activity in A549 human lung carcinoma cells (compound 8d displayed the highest level of activity, 4.25 × 10-6 M, after 48 h).

• MeSH
• akridiny chemická syntéza   chemie   farmakologie   MeSH
• antitumorózní látky chemická syntéza   chemie   farmakologie   MeSH
• buňky A549 MeSH
• DNA-topoisomerasy I metabolismus   MeSH
• DNA-topoisomerasy typu II metabolismus   MeSH
• DNA účinky léků   MeSH
• halogenace MeSH
• inhibitory topoisomerasy I chemická syntéza   chemie   farmakologie   MeSH
• inhibitory topoisomerasy II chemická syntéza   chemie   farmakologie   MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• molekulární struktura MeSH
• proliferace buněk účinky léků   MeSH
• skot MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH