@article{AbdelhameedEltamanyHaletal.2020, author = {Abdelhameed, Reda F. A. and Eltamany, Enas E. and Hal, Dina M. and Ibrahim, Amany K. and AboulMagd, Asmaa M. and Al-Warhi, Tarfah and Youssif, Khayrya A. and Abd El-kader, Adel M. and Hassanean, Hashim A. and Fayez, Shaimaa and Bringmann, Gerhard and Ahmed, Safwat A. and Abdelmohsen, Usama Ramadan}, title = {New cytotoxic cerebrosides from the Red Sea cucumber Holothuria spinifera supported by in-silico studies}, series = {Marine Drugs}, volume = {18}, journal = {Marine Drugs}, number = {8}, issn = {1660-3397}, doi = {10.3390/md18080405}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-211089}, year = {2020}, abstract = {Bioactivity-guided fractionation of a methanolic extract of the Red Sea cucumber Holothuria spinifera and LC-HRESIMS-assisted dereplication resulted in the isolation of four compounds, three new cerebrosides, spiniferosides A (1), B (2), and C (3), and cholesterol sulfate (4). The chemical structures of the isolated compounds were established on the basis of their 1D NMR and HRMS spectral data. Metabolic profiling of the H. spinifera extract indicated the presence of diverse secondary metabolites, mostly hydroxy fatty acids, diterpenes, triterpenes, and cerebrosides. The isolated compounds were tested for their in vitro cytotoxicities against the breast adenocarcinoma MCF-7 cell line. Compounds 1, 2, 3, and 4 displayed promising cytotoxic activities against MCF-7 cells, with IC\(_{50}\) values of 13.83, 8.13, 8.27, and 35.56 µM, respectively, compared to that of the standard drug doxorubicin (IC\(_{50}\) 8.64 µM). Additionally, docking studies were performed for compounds 1, 2, 3, and 4 to elucidate their binding interactions with the active site of the SET protein, an inhibitor of protein phosphatase 2A (PP2A), which could explain their cytotoxic activity. This study highlights the important role of these metabolites in the defense mechanism of the sea cucumber against fouling organisms and the potential uses of these active molecules in the design of new anticancer agents.}, language = {en} } @article{AbdelhameedHabibEltahawyetal.2020, author = {Abdelhameed, Reda F. A. and Habib, Eman S. and Eltahawy, Nermeen A. and Hassanean, Hashim A. and Ibrahim, Amany K. and Mohammed, Anber F. and Fayez, Shaimaa and Hayallah, Alaa M. and Yamada, Koji and Behery, Fathy A. and Al-Sanea, Mohammad M. and Alzarea, Sami I. and Bringmann, Gerhard and Ahmed, Safwat A. and Abdelmohsen, Usama Ramadan}, title = {New cytotoxic natural products from the Red Sea sponge Stylissa carteri}, series = {Marine Drugs}, volume = {18}, journal = {Marine Drugs}, number = {5}, issn = {1660-3397}, doi = {10.3390/md18050241}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-205795}, year = {2020}, abstract = {Bioactivity-guided isolation supported by LC-HRESIMS metabolic profiling led to the isolation of two new compounds, a ceramide, stylissamide A (1), and a cerebroside, stylissoside A (2), from the methanol extract of the Red Sea sponge Stylissa carteri. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. The bioactive extract's metabolomic profiling showed the existence of various secondary metabolites, mainly oleanane-type saponins, phenolic diterpenes, and lupane triterpenes. The in vitro cytotoxic activity of the isolated compounds was tested against two human cancer cell lines, MCF-7 and HepG2. Both compounds, 1 and 2, displayed strong cytotoxicity against the MCF-7 cell line, with IC\(_{50}\) values at 21.1 ± 0.17 µM and 27.5 ± 0.18 µM, respectively. They likewise showed a promising activity against HepG2 with IC\(_{50}\) at 36.8 ± 0.16 µM for 1 and IC\(_{50}\) 30.5 ± 0.23 µM for 2 compared to the standard drug cisplatin. Molecular docking experiments showed that 1 and 2 displayed high affinity to the SET protein and to inhibitor 2 of protein phosphatase 2A (I2PP2A), which could be a possible mechanism for their cytotoxic activity. This paper spreads light on the role of these metabolites in holding fouling organisms away from the outer surface of the sponge, and the potential use of these defensive molecules in the production of novel anticancer agents.}, language = {en} } @article{AbdelhameedHabibGodaetal.2020, author = {Abdelhameed, Reda F. A. and Habib, Eman S. and Goda, Marwa S. and Fahim, John Refaat and Hassanean, Hashem A. and Eltamany, Enas E. and Ibrahim, Amany K. and AboulMagd, Asmaa M. and Fayez, Shaimaa and Abd El-kader, Adel M. and Al-Warhi, Tarfah and Bringmann, Gerhard and Ahmed, Safwat A. and Abdelmohsen, Usama Ramadan}, title = {Thalassosterol, a New Cytotoxic Aromatase Inhibitor Ergosterol Derivative from the Red Sea Seagrass Thalassodendron ciliatum}, series = {Marine Drugs}, volume = {18}, journal = {Marine Drugs}, number = {7}, doi = {10.3390/md18070354}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236085}, year = {2020}, abstract = {Thalassodendron ciliatum (Forssk.) Den Hartog is a seagrass belonging to the plant family Cymodoceaceae with ubiquitous phytoconstituents and important pharmacological potential, including antioxidant, antiviral, and cytotoxic activities. In this work, a new ergosterol derivative named thalassosterol (1) was isolated from the methanolic extract of T. ciliatum growing in the Red Sea, along with two known first-reported sterols, namely ergosterol (2) and stigmasterol (3), using different chromatographic techniques. The structure of the new compound was established based on 1D and 2D NMR spectroscopy and high-resolution mass spectrometry (HR-MS) and by comparison with the literature data. The new ergosterol derivative showed significant in vitro antiproliferative potential against the human cervical cancer cell line (HeLa) and human breast cancer (MCF-7) cell lines, with IC\(_{50}\) values of 8.12 and 14.24 µM, respectively. In addition, docking studies on the new sterol 1 explained the possible binding interactions with an aromatase enzyme; this inhibition is beneficial in both cervical and breast cancer therapy. A metabolic analysis of the crude extract of T. ciliatum using liquid chromatography combined with high-resolution electrospray ionization mass spectrometry (LC-ESI-HR-MS) revealed the presence of an array of phenolic compounds, sterols and ceramides, as well as di- and triglycerides.}, language = {en} } @article{AltmannMutWolfetal.2021, author = {Altmann, Stephan and Mut, J{\"u}rgen and Wolf, Natalia and Meißner-Weigl, Jutta and Rudert, Maximilian and Jakob, Franz and Gutmann, Marcus and L{\"u}hmann, Tessa and Seibel, J{\"u}rgen and Ebert, Regina}, title = {Metabolic glycoengineering in hMSC-TERT as a model for skeletal precursors by using modified azide/alkyne monosaccharides}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {6}, issn = {1422-0067}, doi = {10.3390/ijms22062820}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259247}, year = {2021}, abstract = {Metabolic glycoengineering enables a directed modification of cell surfaces by introducing target molecules to surface proteins displaying new features. Biochemical pathways involving glycans differ in dependence on the cell type; therefore, this technique should be tailored for the best results. We characterized metabolic glycoengineering in telomerase-immortalized human mesenchymal stromal cells (hMSC-TERT) as a model for primary hMSC, to investigate its applicability in TERT-modified cell lines. The metabolic incorporation of N-azidoacetylmannosamine (Ac\(_4\)ManNAz) and N-alkyneacetylmannosamine (Ac\(_4\)ManNAl) into the glycocalyx as a first step in the glycoengineering process revealed no adverse effects on cell viability or gene expression, and the in vitro multipotency (osteogenic and adipogenic differentiation potential) was maintained under these adapted culture conditions. In the second step, glycoengineered cells were modified with fluorescent dyes using Cu-mediated click chemistry. In these analyses, the two mannose derivatives showed superior incorporation efficiencies compared to glucose and galactose isomers. In time-dependent experiments, the incorporation of Ac\(_4\)ManNAz was detectable for up to six days while Ac\(_4\)ManNAl-derived metabolites were absent after two days. Taken together, these findings demonstrate the successful metabolic glycoengineering of immortalized hMSC resulting in transient cell surface modifications, and thus present a useful model to address different scientific questions regarding glycosylation processes in skeletal precursors.}, language = {en} } @article{BastChristlHuisgenetal.1972, author = {Bast, K. and Christl, Manfred and Huisgen, R. and Mack, W.}, title = {Additionen der Nitriloxide an CN-Mehrfachbindungen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57879}, year = {1972}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {de} } @article{BastChristlHuisgenetal.1973, author = {Bast, K. and Christl, Manfred and Huisgen, R. and Mack, W.}, title = {Relative Dipolarophilen-Aktivit{\"a}ten bei Cycloadditionen des Benzonitriloxids}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57935}, year = {1973}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {de} } @article{BastChristlHuisgenetal.1973, author = {Bast, K. and Christl, Manfred and Huisgen, R. and Mack, W. and Sustmann, R.}, title = {Additionen des Benzonitriloxids an olefinische und acetylenische Dipolarophile}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57905}, year = {1973}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {de} } @article{BastChristlHuisgenetal.1973, author = {Bast, K. and Christl, Manfred and Huisgen, R. and Sustmann, R.}, title = {Zur Anlagerung des Benzonitriloxids an α,β-unges{\"a}ttigte Carbons{\"a}ureester}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57912}, year = {1973}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {de} } @article{BecamWalterBurgertetal.2017, author = {Becam, J{\´e}r{\^o}me and Walter, Tim and Burgert, Anne and Schlegel, Jan and Sauer, Markus and Seibel, J{\"u}rgen and Schubert-Unkmeir, Alexandra}, title = {Antibacterial activity of ceramide and ceramide analogs against pathogenic Neisseria}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, doi = {10.1038/s41598-017-18071-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159367}, pages = {17627}, year = {2017}, abstract = {Certain fatty acids and sphingoid bases found at mucosal surfaces are known to have antibacterial activity and are thought to play a more direct role in innate immunity against bacterial infections. Herein, we analysed the antibacterial activity of sphingolipids, including the sphingoid base sphingosine as well as short-chain C\(_{6}\) and long-chain C\(_{16}\)-ceramides and azido-functionalized ceramide analogs against pathogenic Neisseriae. Determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) demonstrated that short-chain ceramides and a ω-azido-functionalized C\(_{6}\)-ceramide were active against Neisseria meningitidis and N. gonorrhoeae, whereas they were inactive against Escherichia coli and Staphylococcus aureus. Kinetic assays showed that killing of N. meningitidis occurred within 2 h with ω-azido-C\(_{6}\)-ceramide at 1 X the MIC. Of note, at a bactericidal concentration, ω-azido-C\(_{6}\)-ceramide had no significant toxic effect on host cells. Moreover, lipid uptake and localization was studied by flow cytometry and confocal laser scanning microscopy (CLSM) and revealed a rapid uptake by bacteria within 5 min. CLSM and super-resolution fluorescence imaging by direct stochastic optical reconstruction microscopy demonstrated homogeneous distribution of ceramide analogs in the bacterial membrane. Taken together, these data demonstrate the potent bactericidal activity of sphingosine and synthetic short-chain ceramide analogs against pathogenic Neisseriae.}, language = {en} } @article{BentleyChristlKemmeretal.1994, author = {Bentley, T. W. and Christl, Manfred and Kemmer, R. and Llewellyn, G. and Oakley, J. E.}, title = {Kinetic and Spectroscopic Characterisation of Highly Reactive Methanesulfonates. Leaving Group Effects for Solvolyses and Comments on Geminal Electronic Effects Influencing S\(_N\)1 Reactivity}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58748}, year = {1994}, abstract = {Highly reactive methanesulfonates (mesylates, ROMs) have been prepared from 1-phenylethanol. cyclohex-2-en-1-ol, diphenylmethanol and p-methoxybenzyl alcohol by treatment with methanesulfonyl chloride and triethylamine in dichloro- or trichloro-methane at - 20 to 0 °C. The mesylates. characterised in solution by \(^1\)H and \(^{13}\)C NMR at -20 °C, were obtained in satisfactory purity (ca. 95\%) in cold solutions but they decomposed by reaction with chloride, triethylamine or the parent alcohol. Rate constants for solvolyses in aqueous acetone and aqueous ethanol have been determined by a fast response conductimetric method. Product selectivities for solvolyses of pmethoxybenzyl mesylate in aqueous ethanol and methanol at 0 °C have been determined by HPLC. From additional new or Iiterature kinetic data for solvolyses of corresponding bromides. chlorides and p-nitrobenzoates (OPNB). Br/CI. OMs/Br and OMs/OPNB rate ratios were calculated; the results are consistent with electronic effects stabilising the carbocationic transition states and increasing OMs/Br rate ratios for these SN 1 solvolyses; none of the evidence supports a geminal electronic effect on Br/CI rate ratios (e.g. caused by stabilisation of the initial state in pmethoxybenzyl chloride). Steric effects on ester /halide rate ratios for solvolyses of tertiary substrates are confirmed. Relative rates over a 10\(^{16}\) range for ester and halide leaving groups are evaluated for solvolyses of 1-phenylethyl substrates in 80\% ethanol-water. updating previous work by Noyce et al. (1972).}, subject = {Organische Chemie}, language = {en} } @article{BentleyChristlNorman1991, author = {Bentley, T. W. and Christl, Manfred and Norman, S. J.}, title = {Methanesulfonate/p-Nitrobenzoate and p-Toluenesulfonate/p-Nitrobenzoate Rate Ratios. Solvolyses of 1-Adamantyl and Benzhydryl Substrates}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58599}, year = {1991}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {en} } @article{BentleyNormanGerstneretal.1993, author = {Bentley, T. W. and Norman, S. J. and Gerstner, E. and Kemmer, R. and Christl, Manfred}, title = {Solvolysis of Tricyclo[3.1.0.0\(^{2,6}\)]hex-3-yl and Bicyclo[2.1.1]hex-2-yl Sulfonates}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58689}, year = {1993}, abstract = {No abstract available}, subject = {Organische Chemie}, language = {en} } @article{BialasZitzlerKunkelKirchneretal.2016, author = {Bialas, David and Zitzler-Kunkel, Andr{\´e} and Kirchner, Eva and Schmidt, David and W{\"u}rthner, Frank}, title = {Structural and quantum chemical analysis of exciton coupling in homo- and heteroaggregate stacks of merocyanines}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms12949}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170200}, year = {2016}, abstract = {Exciton coupling is of fundamental importance and determines functional properties of organic dyes in (opto-)electronic and photovoltaic devices. Here we show that strong exciton coupling is not limited to the situation of equal chromophores as often assumed. Quadruple dye stacks were obtained from two bis(merocyanine) dyes with same or different chromophores, respectively, which dimerize in less-polar solvents resulting in the respective homo- and heteroaggregates. The structures of the quadruple dye stacks were assigned by NMR techniques and unambiguously confirmed by single-crystal X-ray analysis. The heteroaggregate stack formed from the bis(merocyanine) bearing two different chromophores exhibits remarkably different ultraviolet/vis absorption bands compared with those of the homoaggregate of the bis(merocyanine) comprising two identical chromophores. Quantum chemical analysis based on an extension of Kasha's exciton theory appropriately describes the absorption properties of both types of stacks revealing strong exciton coupling also between different chromophores within the heteroaggregate.}, language = {en} } @article{BinasBessiSchwalbe2020, author = {Binas, Oliver and Bessi, Irene and Schwalbe, Harald}, title = {Structure Validation of G-Rich RNAs in Noncoding Regions of the Human Genome}, series = {ChemBioChem}, volume = {21}, journal = {ChemBioChem}, number = {11}, doi = {10.1002/cbic.201900696}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214892}, pages = {1656 -- 1663}, year = {2020}, abstract = {We present the rapid biophysical characterization of six previously reported putative G-quadruplex-forming RNAs from the 5′-untranslated region (5′-UTR) of silvestrol-sensitive transcripts for investigation of their secondary structures. By NMR and CD spectroscopic analysis, we found that only a single sequence—[AGG]\(_{2}\)[CGG]\(_{2}\)C—folds into a single well-defined G-quadruplex structure. Sequences with longer poly-G strands form unspecific aggregates, whereas CGG-repeat-containing sequences exhibit a temperature-dependent equilibrium between a hairpin and a G-quadruplex structure. The applied experimental strategy is fast and provides robust readout for G-quadruplex-forming capacities of RNA oligomers.}, language = {en} } @article{BoldStolteShoyamaetal.2022, author = {Bold, Kevin and Stolte, Matthias and Shoyama, Kazutaka and Holzapfel, Marco and Schmiedel, Alexander and Lambert, Christoph and W{\"u}rthner, Frank}, title = {Macrocyclic donor-acceptor dyads composed of a perylene bisimide dye surrounded by oligothiophene bridges}, series = {Angewandte Chemie Internationale Edition}, volume = {61}, journal = {Angewandte Chemie Internationale Edition}, number = {1}, doi = {10.1002/anie.202113598}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256569}, year = {2022}, abstract = {Two macrocyclic architectures comprising oligothiophene strands that connect the imide positions of a perylene bisimide (PBI) dye have been synthesized via a platinum-mediated cross-coupling strategy. The crystal structure of the double bridged PBI reveals all syn-arranged thiophene units that completely enclose the planar PBI chromophore via a 12-membered macrocycle. The target structures were characterized by steady-state UV/Vis absorption, fluorescence and transient absorption spectroscopy, as well as cyclic and differential pulse voltammetry. Both donor-acceptor dyads show ultrafast F{\"o}rster Resonance Energy Transfer and photoinduced electron transfer, thereby leading to extremely low fluorescence quantum yields even in the lowest polarity cyclohexane solvent.}, language = {en} } @article{BoldStolteShoyamaetal.2022, author = {Bold, Kevin and Stolte, Matthias and Shoyama, Kazutaka and Krause, Ana-Maria and Schmiedel, Alexander and Holzapfel, Marco and Lambert, Christoph and W{\"u}rthner, Frank}, title = {Macrocyclic Donor-Acceptor Dyads Composed of Oligothiophene Half-Cycles and Perylene Bisimides}, series = {Chemistry - A European Journal}, volume = {28}, journal = {Chemistry - A European Journal}, number = {30}, doi = {10.1002/chem.202200355}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-276435}, year = {2022}, abstract = {A series of donor-acceptor (D-A) macrocyclic dyads consisting of an electron-poor perylene bisimide (PBI) π-scaffold bridged with electron-rich α-oligothiophenes bearing four, five, six and seven thiophene units between the two phenyl-imide substituents has been synthesized and characterized by steady-state UV/Vis absorption and fluorescence spectroscopy, cyclic and differential pulse voltammetry as well as transient absorption spectroscopy. Tying the oligothiophene strands in a conformationally fixed macrocyclic arrangement leads to a more rigid π-scaffold with vibronic fine structure in the respective absorption spectra. Electrochemical analysis disclosed charged state properties in solution which are strongly dependent on the degree of rigidification within the individual macrocycle. Investigation of the excited state dynamics revealed an oligothiophene bridge size-dependent fast charge transfer process for the macrocyclic dyads upon PBI subunit excitation.}, language = {en} } @article{BrennerGeigerSchlegeletal.2023, author = {Brenner, Daniela and Geiger, Nina and Schlegel, Jan and Diesendorf, Viktoria and Kersting, Louise and Fink, Julian and Stelz, Linda and Schneider-Schaulies, Sibylle and Sauer, Markus and Bodem, Jochen and Seibel, J{\"u}rgen}, title = {Azido-ceramides, a tool to analyse SARS-CoV-2 replication and inhibition — SARS-CoV-2 is inhibited by ceramides}, series = {International Journal of Molecular Sciences}, volume = {24}, journal = {International Journal of Molecular Sciences}, number = {8}, issn = {1422-0067}, doi = {10.3390/ijms24087281}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313581}, year = {2023}, abstract = {Recently, we have shown that C6-ceramides efficiently suppress viral replication by trapping the virus in lysosomes. Here, we use antiviral assays to evaluate a synthetic ceramide derivative α-NH2-ω-N3-C6-ceramide (AKS461) and to confirm the biological activity of C6-ceramides inhibiting SARS-CoV-2. Click-labeling with a fluorophore demonstrated that AKS461 accumulates in lysosomes. Previously, it has been shown that suppression of SARS-CoV-2 replication can be cell-type specific. Thus, AKS461 inhibited SARS-CoV-2 replication in Huh-7, Vero, and Calu-3 cells up to 2.5 orders of magnitude. The results were confirmed by CoronaFISH, indicating that AKS461 acts comparable to the unmodified C6-ceramide. Thus, AKS461 serves as a tool to study ceramide-associated cellular and viral pathways, such as SARS-CoV-2 infections, and it helped to identify lysosomes as the central organelle of C6-ceramides to inhibit viral replication.}, language = {en} } @article{BrixnerKochKullmannetal.2013, author = {Brixner, Tobias and Koch, Federico and Kullmann, Martin and Selig, Ulrike and Nuernberger, Patrick and G{\"o}tz, Daniel C. G. and Bringmann, Gerhard}, title = {Coherent two-dimensional electronic spectroscopy in the Soret band of a chiral porphyrin dimer}, series = {New Journal of Physics}, journal = {New Journal of Physics}, doi = {10.1088/1367-2630/15/2/025006}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96139}, year = {2013}, abstract = {Using coherent two-dimensional (2D) electronic spectroscopy in fully noncollinear geometry, we observe the excitonic coupling of β,β'-linked bis[tetraphenylporphyrinato-zinc(II)] on an ultrafast timescale in the excited state. The results for two states in the Soret band originating from an excitonic splitting are explained by population transfer with approximately 100 fs from the energetically higher to the lower excitonic state. This interpretation is consistent with exemplary calculations of 2D spectra for a model four-level system with coupling.}, language = {en} } @article{BrustNaglerShoyamaetal.2023, author = {Brust, Felix and Nagler, Oliver and Shoyama, Kazutaka and Stolte, Matthias and W{\"u}rthner, Frank}, title = {Organic Light-Emitting Diodes Based on Silandiol-Bay-Bridged Perylene Bisimides}, series = {Advanced Optical Materials}, volume = {11}, journal = {Advanced Optical Materials}, number = {5}, doi = {10.1002/adom.202202676}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312599}, year = {2023}, abstract = {Perylene bisimides (PBIs) are among the best fluorophores but have to be enwrapped for optoelectronic applications by large and heavy substituents to prevent their ππ-stacking, which is known to accelerate non-radiative decay processes in the solid state. Here, light-weight di-tert-butylsilyl groups are introduced to bridge 1,12-dihydroxy and 1,6,7,12-tetrahydroxy PBIs to afford sublimable dyes for vacuum-processed optoelectronic devices. For both new compounds, this substitution provides a twisted and shielded perylene π-core whose, via OSiObridges, rigid structure affords well-resolved absorption and emission spectra with strong fluorescence in solution, as well as in the solid state. The usefulness of these dyes for vacuum-processed optoelectronic devices is demonstrated in organic light-emitting diodes (OLEDs) that show monomer-like emission spectra and high maximum external quantum efficiency (EQEmax) values of up to 3.1\% for the doubly silicon-bridged PBI.}, language = {en} } @article{BruennertSeupelGoyaletal.2023, author = {Br{\"u}nnert, Daniela and Seupel, Raina and Goyal, Pankaj and Bach, Matthias and Schraud, Heike and Kirner, Stefanie and K{\"o}ster, Eva and Feineis, Doris and Bargou, Ralf C. and Schlosser, Andreas and Bringmann, Gerhard and Chatterjee, Manik}, title = {Ancistrocladinium A induces apoptosis in proteasome inhibitor-resistant multiple myeloma cells: a promising therapeutic agent candidate}, series = {Pharmaceuticals}, volume = {16}, journal = {Pharmaceuticals}, number = {8}, issn = {1424-8247}, doi = {10.3390/ph16081181}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-362887}, year = {2023}, abstract = {The N,C-coupled naphthylisoquinoline alkaloid ancistrocladinium A belongs to a novel class of natural products with potent antiprotozoal activity. Its effects on tumor cells, however, have not yet been explored. We demonstrate the antitumor activity of ancistrocladinium A in multiple myeloma (MM), a yet incurable blood cancer that represents a model disease for adaptation to proteotoxic stress. Viability assays showed a potent apoptosis-inducing effect of ancistrocladinium A in MM cell lines, including those with proteasome inhibitor (PI) resistance, and in primary MM cells, but not in non-malignant blood cells. Concomitant treatment with the PI carfilzomib or the histone deacetylase inhibitor panobinostat strongly enhanced the ancistrocladinium A-induced apoptosis. Mass spectrometry with biotinylated ancistrocladinium A revealed significant enrichment of RNA-splicing-associated proteins. Affected RNA-splicing-associated pathways included genes involved in proteotoxic stress response, such as PSMB5-associated genes and the heat shock proteins HSP90 and HSP70. Furthermore, we found strong induction of ATF4 and the ATM/H2AX pathway, both of which are critically involved in the integrated cellular response following proteotoxic and oxidative stress. Taken together, our data indicate that ancistrocladinium A targets cellular stress regulation in MM and improves the therapeutic response to PIs or overcomes PI resistance, and thus may represent a promising potential therapeutic agent.}, language = {en} }