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Gründemann C, Arnhold M, Meier S, Bäcker C, Garcia-Käufer M, Grunewald F, Steinborn C, Klemd Amy M, Wille R, Huber R, Lindequist U. Effects of Inonotus hispidus extracts and compounds on human immunocompetent cells. Am J Transl Res 2017. [DOI: 10.1055/s-0037-1608591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- C Gründemann
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Freiburg, Germany
| | - M Arnhold
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Freiburg, Germany
| | - S Meier
- Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany, Greifswald, Germany
| | - C Bäcker
- Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany, Greifswald, Germany
| | - M Garcia-Käufer
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Freiburg, Germany
| | - F Grunewald
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Freiburg, Germany
| | - C Steinborn
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Freiburg, Germany
| | - M Klemd Amy
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Freiburg, Germany
| | - R Wille
- ABNOBA GmbH, Pforzheim, Germany, Pforzheim, Germany
| | - R Huber
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Freiburg, Germany
| | - U Lindequist
- Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany, Greifswald, Germany
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Gründemann C, Arnhold M, Meier S, Bäcker C, Garcia-Käufer M, Grunewald F, Steinborn C, Klemd AM, Wille R, Huber R, Lindequist U. Effects of Inonotus hispidus Extracts and Compounds on Human Immunocompetent Cells. Planta Med 2016; 82:1359-1367. [PMID: 27428885 DOI: 10.1055/s-0042-111693] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Inonotus hispidus is used as a traditional medicine in China. Previous investigations revealed promising immunomodulatory activity of fruit body extracts of I. hispidus. Bioactivity-guided fractionation showed that hispolon and hispidin were active substances.In this study, we analysed the effects of I. hispidus extract and selected constituents on different types of human immune cells and investigated the potential of I. hispidus extract as a medicinal mushroom. The influence of I. hispidus extract on activity and maturation of human T cells, purified natural killer cells, and dendritic cells was analysed using cytometric-based surface marker expression. The cell division characteristics of the activated T cells were assessed by membrane permeable dye, and the function of natural killer cells was investigated by a degranulation CD107a assay. Apoptosis induction was assessed by surface staining of phosphatidylserine, and camptothecin and cyclosporine A were used individually as controls. Phytochemical analysis, using TLC chromatograms and HPLC analysis, was conducted to characterise the I. hispidus extract. I. hispidus extract increased the activation and diminished the proliferation of activated human T cells in the presence of apoptosis. Natural killer cell activity and function were dose-dependently increased. Surface marker expression of dendritic cells demonstrated that I. hispidus extract has the potential to induce maturation. TLC and HPLC analyses showed that the extract contained hispidin and hispolon. Investigations using hispidin and hispolon demonstrated similar, albeit noncongruent, results with extracts on measured parameters.The results indicate that extracts from I. hispidus and their constituents, hispidin and hispolon, interfere with the function of multiple immune cells, thus providing a rationale for their potential as a medicinal mushroom.
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Affiliation(s)
- Carsten Gründemann
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Medical Center-University of Freiburg, Freiburg, Germany
| | - Mandy Arnhold
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Medical Center-University of Freiburg, Freiburg, Germany
| | - Stefanie Meier
- Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany
| | - Christian Bäcker
- Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany
| | - Manuel Garcia-Käufer
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Medical Center-University of Freiburg, Freiburg, Germany
| | - Franziska Grunewald
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Medical Center-University of Freiburg, Freiburg, Germany
| | - Carmen Steinborn
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Medical Center-University of Freiburg, Freiburg, Germany
| | - Amy Marisa Klemd
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Medical Center-University of Freiburg, Freiburg, Germany
| | | | - Roman Huber
- Center for Complementary Medicine, Institute for Environmental Health Sciences and Hospital Infection Control, Medical Center-University of Freiburg, Freiburg, Germany
| | - Ulrike Lindequist
- Institute of Pharmacy, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany
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Gründemann C, Arnhold M, Meier S, Bäcker C, Garcia-Käufer M, Grunewald F, Steinborn C, Huber R, Lindequist U. Influence of Inonotus hispidus on function of human immune cells. Eur J Integr Med 2016. [DOI: 10.1016/j.eujim.2016.08.128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Bäcker C, Drwal MN, Preissner R, Lindequist U. Inhibition of DNA-Topoisomerase I by Acylated Triterpene Saponins from Pittosporum angustifolium Lodd. Nat Prod Bioprospect 2016; 6:141-7. [PMID: 26803837 PMCID: PMC4805651 DOI: 10.1007/s13659-016-0087-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/13/2016] [Indexed: 05/23/2023]
Abstract
Previous phytochemical investigation of the leaves and seeds of Pittosporum angustifolium Lodd. led to the isolation and structural elucidation of polyphenols and triterpene saponins. Evaluation for cytotoxicity of isolated saponins revealed that the predominant structural feature for a cytotoxic activity are acyl substituents at the oleanane aglycon backbone. The present work reports the results of a screening of 10 selected acylated saponins for their potential to inhibit the human DNA-topoisomerase I, giving rise to IC50 values in a range of 2.8-46.5 µM. To clarify the mode of observed cytotoxic action and, moreover, to distinguish from a pure surfactant effect which is commonly accompanied with saponins, these results indicate an involvement of the topoisomerase I and its role as a possible target structure for a cytotoxic activity. In addition, computational predictions of the fitting of saponins to the topoisomerase I-DNA complex, indicate a similar binding mode to that of clinically used topoisomerase I inhibitors. Ten acylated triterpene saponins from Pittosporum angustifolium were investigated for their potential to inhibit the human DNA-topoisomerase I and computational predictions of the fitting of saponins to the topoisomerase I-DNA complex were carried out.
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Affiliation(s)
- Christian Bäcker
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489, Greifswald, Germany.
| | - Malgorzata N Drwal
- Structural Bioinformatics Group, Institute for Physiology, Charité - University Medicine Berlin, Lindenberger Weg 80, 13125, Berlin, Germany
| | - Robert Preissner
- Structural Bioinformatics Group, Institute for Physiology, Charité - University Medicine Berlin, Lindenberger Weg 80, 13125, Berlin, Germany
| | - Ulrike Lindequist
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489, Greifswald, Germany
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Bäcker C, Jenett-Siems K, Siems K, Niedermeyer TH, Wurster M, Bodtke A, Lindequist U. Taraxastane-type triterpene saponins isolated from Pittosporum angustifolium Lodd. ACTA ACUST UNITED AC 2015. [DOI: 10.1515/znb-2015-0005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Two new taraxastane-type triterpene saponins, named pittangretosides L (1) and C1 (2), were isolated from the leaves of Pittosporum angustifolium Lodd. Their structures were established by NMR spectroscopic, mass spectrometric and chemical means. The in vitro cytotoxicity was evaluated against four cell lines. The compounds exhibited no cytotoxic activity up to a concentration of 130 μm.
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Affiliation(s)
- Christian Bäcker
- Institute of Pharmacy, Department of Pharmaceutical Biology, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Kristina Jenett-Siems
- Institute of Pharmacy, Department of Pharmaceutical Biology, Free University of Berlin, Königin-Luise-Str. 2 + 4, 14195 Berlin, Germany
| | - Karsten Siems
- AnalytiCon Discovery GmbH, Hermannswerder Haus 17, 14473 Potsdam, Germany
| | - Timo H.J. Niedermeyer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Martina Wurster
- Institute of Pharmacy, Department of Pharmaceutical Biology, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Anja Bodtke
- Institute of Pharmacy, Department of Pharmaceutical/Medicinal Chemistry, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Ulrike Lindequist
- Institute of Pharmacy, Department of Pharmaceutical Biology, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
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Bäcker C, Jenett-Siems K, Siems K, Wurster M, Bodtke A, Niedermeyer THJ, Lindequist U. New Mono- and Bisdesmosidic Triterpene Glycosides from Pittosporum angustifolium Lodd. ACTA ACUST UNITED AC 2015. [DOI: 10.5560/znb.2014-4143] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Fifteen new mono- and bisdesmosidic triterpene saponins, named pittangretosides J, K, M, Q- Z, A1, and B1, along with three known compounds were isolated from the leaves of Pittosporum angustifolium. By spectroscopic, mass spectrometric and chemical evidence, their structures were established as glycosides of A1- and R1-barrigenol, barringtogenol C and camelliagenin A backbones
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Affiliation(s)
- Christian Bäcker
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Kristina Jenett-Siems
- Department of Pharmaceutical Biology, Institute of Pharmacy, Free University of Berlin, Königin-Luise-Str. 2 + 4, 14195 Berlin, Germany
| | - Karsten Siems
- AnalytiCon Discovery GmbH, Hermannswerder Haus 17, 14473 Potsdam, Germany
| | - Martina Wurster
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Anja Bodtke
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Timo H. J. Niedermeyer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Ulrike Lindequist
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
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Bäcker C, Jenett-Siems K, Siems K, Wurster M, Bodtke A, Lindequist U. Cytotoxic Saponins from the Seeds of Pittosporum angustifolium. ACTA ACUST UNITED AC 2014; 69:191-8. [DOI: 10.5560/znc.2014-0011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Three new acylated R1-barrigenol triterpene glycosides, 1 - 3, were isolated from the seeds of Pittosporum angustifolium Lodd. together with four known glycosides, 4 - 7, containing R1- and A1-barrigenol backbones. On the basis of spectroscopic, spectrometric, and chemical analyses the novel compounds were named pittangretosides N- P and established as 21ß-acetoxy- 22α-angeloyloxy- (1), 21ß-acetoxy-22α-(2-acetoxy-2-methylbutyroyloxy)- (2), and 21ß-(2-methylbutyroyloxy)- 22α-acetoxy-3ß-[b-D-glucopyranosyl- (1→2)]-[α-L-arabinopyranosyl-(1→3)]-[α- L-arabinofuranosyl-(1!4)]-ß-D-glucuronopyranosyloxyolean-12-ene-15α,16α,28-triol (3). Evaluation of the in vitro cytotoxicity against three tumour cell lines and one non-tumourigenic cell line revealed antiproliferative effects with IC50 values in a range of 1:74 - 34:1 μM
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Affiliation(s)
- Christian Bäcker
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, D-17489 Greifswald, Germany. Fax: +49(0)3834864885
| | - Kristina Jenett-Siems
- Department of Pharmaceutical Biology, Institute of Pharmacy, Free University of Berlin, Königin-Luise-Str. 2+4, D-14195 Berlin, Germany
| | - Karsten Siems
- AnalytiCon Discovery GmbH, Hermannswerder Haus 17, D-14473 Potsdam, Germany
| | - Martina Wurster
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, D-17489 Greifswald, Germany
| | - Anja Bodtke
- Department of Pharmaceutical=Medicinal Chemistry, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, D-17489 Greifswald, Germany
| | - Ulrike Lindequist
- Department of Pharmaceutical Biology, Institute of Pharmacy, Ernst Moritz Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 17, D-17489 Greifswald, Germany
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Bäcker C, Jenett-Siems K, Siems K, Wurster M, Bodtke A, Chamseddin C, Crüsemann M, Lindequist U. Triterpene glycosides from the leaves of Pittosporum angustifolium. Planta Med 2013; 79:1461-1469. [PMID: 24046217 DOI: 10.1055/s-0033-1350806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Phytochemical investigation of the leaves of Pittosporum angustifolium resulted in the isolation and structural elucidation of nine new triterpene saponins, named pittangretosides A-I (1-9), together with a known compound (10). Mainly by NMR and HRESIMS experiments, eight compounds were identified as A1-barrigenol glycosides (1-7, 10), whereas two compounds exhibited an unusual 17,22-seco-backbone of oleanolic acid (8, 9). All compounds were evaluated for their in vitro cytotoxicities against human urinary bladder carcinoma cells (5637). Only compounds with an angeloyl-residue at C-22 of the aglycone (1-4 and 10) showed antiproliferative effects with IC50 values of 4.1, 5.2, 2.1, 17.9, and 2.4 µM, respectively.
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Affiliation(s)
- Christian Bäcker
- Institute of Pharmacy, Department of Pharmaceutical Biology, Ernst Moritz Arndt University Greifswald, Greifswald, Germany
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Naderi-Heiden A, Gleiss A, Bäcker C, Bieber D, Nassan-Agha H, Kasper S, Frey R. Mortality and employment after in-patient opiate detoxification. Eur Psychiatry 2010; 27:294-300. [PMID: 20650614 DOI: 10.1016/j.eurpsy.2010.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 05/06/2010] [Accepted: 05/08/2010] [Indexed: 11/24/2022] Open
Abstract
AIM We considered that completed opiate detoxification resulted in increased life expectancy and earning capacity as compared to non-completed detoxification. METHODS The cohort study sample included pure opioid or poly-substance addicts admitted for voluntary in-patient detoxification between 1997 and 2004. Of 404 patients, 58.7% completed the detoxification program and 41.3% did not. The Austrian Social Security Institution supplied data on survival and employment records for every single day in the individual observation period between discharge and December 2007. Statistical analyses included the calculation of standardized mortality rates for the follow-up period of up to 11 years. RESULTS The standardized mortality ratios (SMRs) were between 13.5 and 17.9 during the first five years after discharge, thereafter they fell clearly with time. Mortality did not differ statistically significantly between completers and non-completers. The median employment rate was insignificantly higher in completers (12.0%) than in non-completers (5.5%). The odds for being employed were higher in pure opioid addicts than in poly-substance addicts (p=0.003). CONCLUSIONS The assumption that completers of detoxification treatment have a better outcome than non-completers has not been confirmed. The decrease in mortality with time elapsed since detoxification is interesting. Pure opioid addicts had better employment prospects than poly-substance addicts.
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Affiliation(s)
- A Naderi-Heiden
- Division of Biological Psychiatry, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
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Kaufmann RM, Kraft B, Frey R, Winkler D, Weiszenbichler S, Bäcker C, Kasper S, Kress HG. Acute psychotropic effects of oral cannabis extract with a defined content of Delta9-tetrahydrocannabinol (THC) in healthy volunteers. Pharmacopsychiatry 2009; 43:24-32. [PMID: 20178093 DOI: 10.1055/s-0029-1237397] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION The medical use of cannabinoids is limited mainly by their undesirable effects. With respect to acute psychotropic effects, the aim of this study is the comparison of an oral cannabis extract and low-dose diazepam in a cross-over experiment in drug-naïve healthy women. METHODS Sixteen healthy females participated in this randomized, double-blind, active comparator-controlled, single-dose, balanced 2-way cross-over study. Cannabis extract with standardised Delta (9)-tetrahydrocannabinol (THC) content (20 mg) or active placebo (5 mg diazepam) was administered orally. Subjects were assessed by self- and observer-rated visual analogue scales (VAS), the BRIEF PSYCHIATRIC RATING SCALE (BPRS) and three psychomotor tests up to 6 h after administration. RESULTS VAS showed significantly elevated fatigue, drowsiness, dizziness, and "feeling high" after cannabis as compared to baseline and diazepam. BPRS scores were significantly higher after cannabis intake. Only in one psychomotor test a decrease of psychomotor activity after cannabis was evident. One subject in the cannabis condition experienced severe transient psychotic symptoms. DISCUSSION Orally administered cannabis produced significant central depressant side-effects compared to diazepam, mostly subjective effects (VAS) but marginal effects in psychomotor performance in 15 healthy females. Regarding the medical use of cannabis, a rigorous benefit-risk analysis and an exact psychiatric assessment before and during treatment are necessary.
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Affiliation(s)
- R M Kaufmann
- Division of Biological Psychiatry, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria.
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Hohn HP, Grümmer R, Bosserhoff S, Graf-Lingnau S, Reuss B, Bäcker C, Denker HW. The role of matrix contact and of cell-cell interactions in choriocarcinoma cell differentiation. Eur J Cell Biol 1996; 69:76-85. [PMID: 8825026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cell differentiation is supported much better by gels of extracellular matrix than by the same matrix provided as a rigid substrate. Many cell types including normal and malignant trophoblast cells, however, form multicellular multilayered aggregates on matrix gels with increased cell-to-cell contacts as compared to regular monolayers on rigid matrix substrates. In such cultures, it remained open, so far, whether stimulated expression of differentiation markers is caused by enhanced cell-to-cell communication or is displayed only by cells in direct contact to the gel. Therefore, choriocarcinoma cells (BeWo) were grown as aggregates: (a) on gels of the basement membrane-like Matrigel, (b) on plastic coated with poly-HEMA, or (c) as aggregates (spheroids) in suspension culture. Production of the differentiation marker chorionic gonadotropin was stimulated significantly in aggregates attached to gels of Matrigel or to the poly-HEMA substrate but not in suspended spheroids. With respect to cell-cell communications, however, expression of E-cadherin mRNA was not altered in any type of aggregates, as compared to control cultures on plastic. The expression of connexin43 mRNA (not of connexin26) was increased only in suspended spheroids, while microinjection of the fluorescent dye Lucifer Yellow suggested that cell communication via gap junctions was absent from cells grown as monolayers and was not induced in any type of aggregate. When cells were grown on gels of Matrigel, the relevance of direct cellular contact to the substrate for differentiation was analyzed by immunohistochemistry. Trophoblastic differentiation markers (chorionic gonadotropin, placental lactogen, placenta-type alkaline phosphatase, and pregnancy-specific glycoprotein beta 1) as well as the proliferation marker Ki-67 were not preferentially expressed in cells that were in contact with the gel. Similar random distributions of all these markers were also observed in spheroids cultured in suspension. The distributions of several matrix molecules and of different integrins were comparable between aggregates on matrix gels and those in suspension culture. According to these data, cell-cell communication appears to play a subordinate role for cytodifferentiation in cell aggregates on matrix gels, so that substrate anchorage and physical properties of the substrate may be the decisive factors. Interestingly, however, direct contact to the substrate does not seem to be essential for the stimulation of differentiation in cells on matrix gels. The results are discussed in the context of the "tensegrity"-model for cell-matrix interactions in which proper mechanical properties of the substrate are important for the regulation of cell differentiation by allowing a balanced integrity of external and cell-internal tensile forces.
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Affiliation(s)
- H P Hohn
- Institut für Anatomie, Universitätsklinikum Essen, Germany
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