Publications by authors named "Debora Wernitznig"

8 Publications

  • Page 1 of 1

Micro-droplet-based calibration for quantitative elemental bioimaging by LA-ICPMS.

Anal Bioanal Chem 2021 May 5. Epub 2021 May 5.

Institute of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 38, 1090, Vienna, Austria.

In this work, a novel standardization strategy for quantitative elemental bioimaging is evaluated. More specifically, multi-element quantification by laser ablation-inductively coupled plasma-time-of-flight mass spectrometry (LA-ICP-TOFMS) is performed by multi-point calibration using gelatin-based micro-droplet standards and validated using in-house produced reference materials. Fully automated deposition of micro-droplets by micro-spotting ensured precise standard volumes of 400 ± 5 pL resulting in droplet sizes of around 200 μm in diameter. The small dimensions of the micro-droplet standards and the use of a low-dispersion laser ablation setup reduced the analysis time required for calibration by LA-ICPMS significantly. Therefore, as a key advance, high-throughput analysis (pixel acquisition rates of more than 200 Hz) enabled to establish imaging measurement sequences with quality control- and standardization samples comparable to solution-based quantification exercises by ICP-MS. Analytical figures of merit such as limit of detection, precision, and accuracy of the calibration approach were assessed for platinum and for elements with biological key functions from the lower mass range (phosphorus, copper, and zinc). As a proof-of-concept application, the tool-set was employed to investigate the accumulation of metal-based anticancer drugs in multicellular tumor spheroid models at clinically relevant concentrations. Graphical abstract.
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http://dx.doi.org/10.1007/s00216-021-03357-wDOI Listing
May 2021

Complex formation of an estrone-salicylaldehyde semicarbazone hybrid with copper(II) and gallium(III): Solution equilibria and biological activity.

J Inorg Biochem 2021 Jul 24;220:111468. Epub 2021 Apr 24.

Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary; MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary.

The solution chemical properties such as proton dissociation, complex formation with copper(II) and gallium(III) ions in addition to antibacterial and antitumor activity of a novel tridentate salicyaldehyde semicarbazone-estrone hybrid (estrone-SC) and a related bicyclic compound (thn-SC) were investigated. The crystal structure of complex [Cu(thn-SCH)Cl] was studied by single crystal X-ray diffraction method. Estrone-SC and thn-SC form mono-ligand complexes with Cu(II) characterized by relatively high stability, however, they are much less stable than their thiosemicarbazone analogues. The neutral Cu(II) complexes with (O,N,O)(HO) coordination mode predominate at physiological pH. Estrone-SC and thn-SC are more efficient Ga(III) binders in comparison with thiosemicarbazones, although the complexes also suffer dissociation at pH 7.4. The Cu(II) complex of estrone-SC displayed significant cytotoxicity in A549, SW480 and CH1/PA cancer cells, and moderate apoptosis induction and ROS formation. The semicarbazone compounds did not exhibit antibacterial effect; unlike the related Cu(II)-thiosemicarbazone complexes represented by the fairly low MIC values (3-50 μM) obtained on the Gram-positive Staphylococcus aureus and Enterococcus faecalis bacteria.
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http://dx.doi.org/10.1016/j.jinorgbio.2021.111468DOI Listing
July 2021

Plecstatin-1 induces an immunogenic cell death signature in colorectal tumour spheroids.

Metallomics 2020 12;12(12):2121-2133

Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 42, 1090, Vienna, Austria.

Organometallic metal(arene) anticancer agents were believed to confer low selectivity for potential cellular targets. However, the ruthenium(arene) pyridinecarbothioamide (plecstatin-1) showed target selectivity for plectin, a scaffold protein and cytolinker. We employed a three-dimensional cancer spheroid model and showed that plecstatin-1 limited spheroid growth, induced changes in the morphology and in the architecture of tumour spheroids by disrupting the cytoskeletal organization. Additionally, we demonstrated that plecstatin-1 induced oxidative stress, followed by the induction of an immunogenic cell death signature through phosphorylation of eIF2α, exposure of calreticulin, HSP90 and HSP70 on the cell membrane and secretion of ATP followed by release of high mobility group box-1.
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http://dx.doi.org/10.1039/d0mt00227eDOI Listing
December 2020

Introducing -, -, and -donor leaving groups: an investigation of the chemical and biological properties of ruthenium, rhodium and iridium thiopyridone piano stool complexes.

Dalton Trans 2020 Nov;49(44):15693-15711

Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090 Vienna, Austria. and Research Cluster "Translational Cancer Therapy Research", Waehringer Strasse 42, 1090 Vienna, Austria.

A series of 15 piano-stool complexes featuring either a RuII, RhIII or IrIII metal center, a bidentate thiopyridone ligand, and different leaving groups was synthesized. The leaving groups were selected in order to cover a broad range of different donor atoms. Thus, 1-methylimidazole served as a N-donor, 1,3,5-triaza-7-phosphaadamantane (pta) as a P-donor, and thiourea as a S-donor. Additionally, three complexes featuring different halido leaving groups (Cl, Br, I) were added. Leaving group alterations were carried out with respect to a possible influence on pharmacokinetic and pharmacodynamic parameters, as well as the cytotoxicity of the respective compounds. The complexes were characterized via NMR spectroscopy, X-ray diffraction (where possible), mass spectrometry, and elemental analysis. Cytotoxicity was assessed in 2D cultures of human cancer cell lines by microculture and clonogenic assays as well as in multicellular tumor spheroids. Furthermore, cellular accumulation studies, flow-cytometric apoptosis and ROS assays, DNA plasmid assays, and laser ablation ICP-MS studies for analyzing the distribution in sections of multicellular tumor spheroids were conducted. This work demonstrates the importance of investigating each piano-stool complexes' properties, as the most promising candidates showed advantages over each other in certain tests/assays. Thus, it was not possible to single out one lead compound, but rather a group of complexes with enhanced cytotoxicity and activity.
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http://dx.doi.org/10.1039/d0dt03165hDOI Listing
November 2020

Synthesis, Modification, and Biological Evaluation of a Library of Novel Water-Soluble Thiopyridone-Based Organometallic Complexes and Their Unexpected (Biological) Behavior.

Chemistry 2020 Apr 6;26(24):5419-5433. Epub 2020 Apr 6.

Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090, Vienna, Austria.

A series of 16 dinuclear thiopyridone-based organometallics with excellent water solubility, increased stability and remarkable cytotoxicity were synthesized and characterized. The complexes of this work formed dimeric species featuring a double positive charge in polar protic solvents, accounting for their outstanding solubility in aqueous solution. Most of them displayed higher antiproliferative activity than their parental thiomaltol complex, with unexpected cytotoxicity trends depending on the employed metal center, ligand modification, and cell line. Insights into their behavior in biological systems were gathered by means of amino-acid interaction studies, cytotoxicity tests in 3D spheroid models, laser ablation, cellular accumulation measurements, as well as cell cycle experiments.
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http://dx.doi.org/10.1002/chem.201905546DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7217150PMC
April 2020

Novel phthiocol-based organometallics with tridentate coordination motif and their unexpected cytotoxic behaviour.

Dalton Trans 2020 Feb;49(5):1393-1397

University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Waehringer Str. 42, A-1090 Vienna, Austria.

Novel phthiocol-based organometallics with in situ formed tridentate N,O,O-coordination motif were established via three-component microwave assisted one-pot reaction. These complexes exhibited enhanced stability in aqueous solution compared to the parental compound KP2048 and showed unexpected cytotoxic behaviour and selectivity in 2D and 3D cell cultures.
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http://dx.doi.org/10.1039/c9dt04462kDOI Listing
February 2020

First-in-class ruthenium anticancer drug (KP1339/IT-139) induces an immunogenic cell death signature in colorectal spheroids in vitro.

Metallomics 2019 06;11(6):1044-1048

Department of Inorganic Chemistry and Research Cluster 'Translational Cancer Therapy Research', Faculty of Chemistry, University of Vienna, Währinger Straße 42, 1090, Vienna, Austria.

The ruthenium complex sodium trans-[tetrachloridobis(1H-indazole)ruthenate(iii)] (KP1339/IT-139) showed preclinical activity in a variety of in vivo tumor models including a highly predictive colon cancer model. The compound has entered clinical trials, where patients experienced disease stabilization accompanied by mild side effects. KP1339, a GRP78 inhibitor, disrupts endoplasmic reticulum (ER) homeostasis leading to cell death. The PERK/eIF2α-branch of the ER plays an essential role in the cascade of events triggering immunogenic cell death (ICD). ICD makes dying cancer cells 'visible' to the immune system, initiating a prolonged immune response against the tumor. As some metal-based chemotherapeutics such as oxaliplatin are able to induce ICD, we investigate whether KP1339 could also trigger induction of the ICD signature. For this, we employ a three-dimensional colon cancer spheroid model and show for the first time that the treatment with KP1339, a ruthenium-based complex, triggers an ICD signature hallmarked by phosphorylation of PERK and eIF2α, exposure of calreticulin on the cell membrane, release of high mobility group box 1 and secretion of ATP.
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http://dx.doi.org/10.1039/c9mt00051hDOI Listing
June 2019

Design, synthesis, nuclear localization, and biological activity of a fluorescent duocarmycin analog, HxTfA.

Bioorg Med Chem Lett 2018 05 5;28(8):1342-1347. Epub 2018 Mar 5.

Department of Chemistry, Hope College, Holland, MI 49423, United States.

HxTfA 4 is a fluorescent analog of a potent cytotoxic and antimalarial agent, TfA 3, which is currently being investigated for the development of an antimalarial vaccine, PlasProtect®. HxTfA contains a p-anisylbenzimidazole or Hx moiety, which is endowed with a blue emission upon excitation at 318 nm; thus enabling it to be used as a surrogate for probing the cellular fate of TfA using confocal microscopy, and addressing the question of nuclear localization. HxTfA exhibits similar selectivity to TfA for A-tract sequences of DNA, alkylating adenine-N3, albeit at 10-fold higher concentrations. It also possesses in vitro cytotoxicity against A549 human lung carcinoma cells and Plasmodium falciparum. Confocal microscopy studies showed for the first time that HxTfA, and by inference TfA, entered A549 cells and localized in the nucleus to exert its biological activity. At biologically relevant concentrations, HxTfA elicits DNA damage response as evidenced by a marked increase in the levels of γH2AX observed by confocal microscopy and immunoblotting studies, and ultimately induces apoptosis.
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http://dx.doi.org/10.1016/j.bmcl.2018.03.016DOI Listing
May 2018