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Rárová L, Sedlák D, Oklestkova J, Steigerová J, Liebl J, Zahler S, Bartůněk P, Kolář Z, Kohout L, Kvasnica M, Strnad M. The novel brassinosteroid analog BR4848 inhibits angiogenesis in human endothelial cells and induces apoptosis in human cancer cells in vitro. J Steroid Biochem Mol Biol 2018; 178:263-271. [PMID: 29307714 DOI: 10.1016/j.jsbmb.2018.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 11/29/2017] [Accepted: 01/04/2018] [Indexed: 01/31/2023]
Abstract
We report the synthesis and detailed biological study of the synthetic brassinosteroid analog 2α,3α-dihydroxy-6-oxo-5α-androstan-17β-yl N-(tert-butoxycarbonyl)-D,L-valinate (BR4848). The panel of cancer cell lines was used for characterization of its antiproliferative activity, yet had no adverse effects in normal human fibroblasts. In HeLa cells, BR4848-induced apoptosis was accompanied by increase of apoptotic subG1 cells, PARP-1 and caspase-7 fragmentation, downregulation of Bcl-2 and Mcl-1, an increase in caspase activity and G2/M phase cell cycle arrest. Antiproliferative properties of BR4848 were exhibited by inhibition of phosphorylation of Akt, Erk1/2 and FAK. Furthermore, the developed analog exhibited in vitro antiangiogenic activity in human umbilical vein endothelial cells (HUVECs). BR4848-induced apoptosis accompanied with G2/M arrest was detected in endothelial cells. BR4848 also inhibited adhesion, tube formation and migration of endothelial cells by inhibition of FAK, Erk 1/2, CDK5, VEGFR2, TNFα-stimulated production of IL-6, angiopoietin-2 and Jagged1. Finally, BR4848 did not modulate the activity nor nuclear translocation of any of the steroid receptors (ERα, ERβ, AR, MR and PR) included in reporter cell-based assays, which excludes the genomic activity of steroid receptors as a contributing factor to the observed biological activities of BR4848.
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Affiliation(s)
- Lucie Rárová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
| | - David Sedlák
- CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Praha 4, Czech Republic.
| | - Jana Oklestkova
- Laboratory of Growth Regulators, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Jana Steigerová
- Laboratory of Molecular Pathology, Department of Clinical and Molecular Pathology, Faculty of Medicine, Palacký University, Hněvotínská 5, 77900, Olomouc, Czech Republic; Institute of Molecular and Translation Medicine, Faculty of Medicine and Dentistry, Palacký University and Faculty Hospital in Olomouc, Hněvotínská 5, 77900, Olomouc, Czech Republic
| | - Johanna Liebl
- Department of Pharmacy, LMU Munich - Center for Drug Research - Pharmaceutical Biology, Butenandtstr. 5-13, Munich, 81377, Germany
| | - Stefan Zahler
- Department of Pharmacy, LMU Munich - Center for Drug Research - Pharmaceutical Biology, Butenandtstr. 5-13, Munich, 81377, Germany
| | - Petr Bartůněk
- CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Praha 4, Czech Republic
| | - Zdeněk Kolář
- Laboratory of Molecular Pathology, Department of Clinical and Molecular Pathology, Faculty of Medicine, Palacký University, Hněvotínská 5, 77900, Olomouc, Czech Republic; Institute of Molecular and Translation Medicine, Faculty of Medicine and Dentistry, Palacký University and Faculty Hospital in Olomouc, Hněvotínská 5, 77900, Olomouc, Czech Republic
| | - Ladislav Kohout
- Laboratory of Growth Regulators, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Miroslav Kvasnica
- Laboratory of Growth Regulators, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 27, 78371, Olomouc, Czech Republic
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Herzog J, Ehrlich SM, Pfitzer L, Liebl J, Fröhlich T, Arnold GJ, Mikulits W, Haider C, Vollmar AM, Zahler S. Cyclin-dependent kinase 5 stabilizes hypoxia-inducible factor-1α: a novel approach for inhibiting angiogenesis in hepatocellular carcinoma. Oncotarget 2017; 7:27108-21. [PMID: 27027353 PMCID: PMC5053636 DOI: 10.18632/oncotarget.8342] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 03/16/2016] [Indexed: 01/25/2023] Open
Abstract
We recently introduced CDK5 as target in HCC, regulating DNA damage response. Based on this and on our previous knowledge about vascular effects of CDK5, we investigated the role of CDK5 in angiogenesis in HCC, one of the most vascularized tumors. We put a special focus on the transcription factor HIF-1α, a master regulator of tumor angiogenesis. The interaction of CDK5 with HIF-1α was tested by Western blot, PCR, reporter gene assay, immunohistochemistry, kinase assay, co-immunoprecipitation, mass spectrometry, and mutation studies. In vivo, different murine HCC models, were either induced by diethylnitrosamine or subcutaneous injection of HUH7 or HepG2 cells. The correlation of vascular density and CDK5 was assessed by immunostaining of a microarray of liver tissues from HCC patients. Inhibition of CDK5 in endothelial or HCC cells reduced HIF-1α levels in vitro and in vivo, and transcription of HIF-1α target genes (VEGFA, VEGFR1, EphrinA1). Mass spectrometry and site directed mutagenesis revealed a stabilizing phosphorylation of HIF-1α at Ser687 by CDK5. Vascular density was decreased in murine HCC models by CDK5 inhibition. In conclusion, inhibiting CDK5 is a multi-modal systemic approach to treat HCC, hitting angiogenesis, as well as the tumor cells themselves.
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Affiliation(s)
- Julia Herzog
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Sandra M Ehrlich
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Lisa Pfitzer
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Johanna Liebl
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Thomas Fröhlich
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center Munich, University of Munich, Munich, Germany
| | - Georg J Arnold
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center Munich, University of Munich, Munich, Germany
| | - Wolfgang Mikulits
- Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Christine Haider
- Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Angelika M Vollmar
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Stefan Zahler
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
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Merk H, Zhang S, Lehr T, Müller C, Ulrich M, Bibb JA, Adams RH, Bracher F, Zahler S, Vollmar AM, Liebl J. Inhibition of endothelial Cdk5 reduces tumor growth by promoting non-productive angiogenesis. Oncotarget 2017; 7:6088-104. [PMID: 26755662 PMCID: PMC4868742 DOI: 10.18632/oncotarget.6842] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 12/29/2015] [Indexed: 11/25/2022] Open
Abstract
Therapeutic success of VEGF-based anti-angiogenic tumor therapy is limited due to resistance. Thus, new strategies for anti-angiogenic cancer therapy based on novel targets are urgently required. Our previous in vitro work suggested that small molecule Cdk5 inhibitors affect angiogenic processes such as endothelial migration and proliferation. Moreover, we recently uncovered a substantial role of Cdk5 in the development of lymphatic vessels. Here we pin down the in vivo impact of endothelial Cdk5 inhibition in angiogenesis and elucidate the underlying mechanism in order to judge the potential of Cdk5 as a novel anti-angiogenic and anti-cancer target. By the use of endothelial-specific Cdk5 knockout mouse models and various endothelial and tumor cell based assays including human tumor xenograft models, we show that endothelial-specific knockdown of Cdk5 results in excessive but non-productive angiogenesis during development but also in tumors, which subsequently leads to inhibition of tumor growth. As Cdk5 inhibition disrupted Notch function by reducing the generation of the active Notch intracellular domain (NICD) and Cdk5 modulates Notch-dependent endothelial cell proliferation and sprouting, we propose that the Dll4/Notch driven angiogenic signaling hub is an important and promising mechanistic target of Cdk5. In fact, Cdk5 inhibition can sensitize tumors to conventional anti-angiogenic treatment as shown in tumor xenograft models. In summary our data set the stage for Cdk5 as a drugable target to inhibit Notch-driven angiogenesis condensing the view that Cdk5 is a promising target for cancer therapy.
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Affiliation(s)
- Henriette Merk
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Siwei Zhang
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Thorsten Lehr
- Clinical Pharmacy, Saarland University, 66123 Saarbrücken, Germany
| | - Christoph Müller
- Department of Pharmacy, Pharmaceutical Chemistry, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Melanie Ulrich
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - James A Bibb
- Department of Psychiatry and Neurology and Neurotherapeutics, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Ralf H Adams
- Department of Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany.,University of Münster, Faculty of Medicine, 48149 Münster, Germany
| | - Franz Bracher
- Department of Pharmacy, Pharmaceutical Chemistry, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Stefan Zahler
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Angelika M Vollmar
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Johanna Liebl
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, 81377 Munich, Germany
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Zhang S, Schneider LS, Vick B, Grunert M, Jeremias I, Menche D, Müller R, Vollmar AM, Liebl J. Anti-leukemic effects of the V-ATPase inhibitor Archazolid A. Oncotarget 2016; 6:43508-28. [PMID: 26496038 PMCID: PMC4791247 DOI: 10.18632/oncotarget.6180] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 10/07/2015] [Indexed: 12/31/2022] Open
Abstract
Prognosis for patients suffering from T-ALL is still very poor and new strategies for T-ALL treatment are urgently needed. Our study shows potent anti-leukemic effects of the myxobacterial V-ATPase inhibitor Archazolid A. Archazolid A reduced growth and potently induced death of leukemic cell lines and human leukemic samples. By inhibiting lysosomal acidification, Archazolid A blocked activation of the Notch pathway, however, this was not the mechanism of V-ATPase inhibition relevant for cell death induction. In fact, V-ATPase inhibition by Archazolid A decreased the anti-apoptotic protein survivin. As underlying mode of action, this work is in line with recent studies from our group demonstrating that Archazolid A induced S-phase cell cycle arrest by interfering with the iron metabolism in leukemic cells. Our study provides evidence for V-ATPase inhibition as a potential new therapeutic option for T-ALL.
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Affiliation(s)
- Siwei Zhang
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, Munich, Germany
| | - Lina S Schneider
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, Munich, Germany
| | - Binje Vick
- Department of Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Michaela Grunert
- Department of Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany
| | - Irmela Jeremias
- Department of Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany.,Department of Oncology/Hematology, Dr. von Haunersches Kinderspital, Munich, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Dirk Menche
- Kekulé-Institut für Organische Chemie und Biochemie der Universität Bonn, Bonn, Germany
| | - Rolf Müller
- Helmholtz Institute for Pharmaceutical Research Saarland, Helmholtz Centre for Infection Research and Department of Pharmaceutical Biotechnology, Saarland University, Saarbrücken, Germany
| | - Angelika M Vollmar
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, Munich, Germany
| | - Johanna Liebl
- Department of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, Munich, Germany
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Liebl J. Cyclin dependent kinase 5—a novel target to enhance the antitumor immune response. Transl Cancer Res 2016. [DOI: 10.21037/tcr.2016.09.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Lymphatic vessel dysfunction is associated with various pathologic conditions, including immunologic disorders, lymphedema, as well as tumor dissemination. Yet, the knowledge about the regulation of lymphatic vessel development is still limited. Our study elucidates cyclin dependent kinase 5 (Cdk5) as an essential player in the development of lymphatic vessels. Deletion of Cdk5 in the mouse endothelium results in severe lymphedema formation and embryonic lethality. On the mechanistic level, we show that Cdk5 phosphorylates the forkhead transcription factor Foxc2 which regulates Foxc2-dependent transcription. In summary, our study elucidates the Cdk5-Foxc2 interaction as a critical regulator of lymphatic vessel development.
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Affiliation(s)
- Johanna Liebl
- Ludwig Maximilians-University Munich, Department of Pharmacy, Pharmaceutical Biology, Munich, Germany
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Unzue A, Lafleur K, Zhao H, Zhou T, Dong J, Kolb P, Liebl J, Zahler S, Caflisch A, Nevado C. Three stories on Eph kinase inhibitors: From in silico discovery to in vivo validation. Eur J Med Chem 2016; 112:347-366. [PMID: 26907157 DOI: 10.1016/j.ejmech.2016.01.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/28/2016] [Accepted: 01/29/2016] [Indexed: 12/15/2022]
Abstract
Several selective and potent EphB4 inhibitors have been discovered, optimized and biophysically characterized by our groups over the past years. On the outset of these discoveries high throughput docking techniques were applied. Herein, we review the optimization campaigns started from three of these hits (Xan-A1, Pyr-A1 and Qui-A1) with emphasis on their in depth in vitro and in vivo characterization, together with previously unpublished angiogenesis and fluorescence based assays.
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Affiliation(s)
- Andrea Unzue
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Karine Lafleur
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Hongtao Zhao
- Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Ting Zhou
- Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Jing Dong
- Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Peter Kolb
- Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Johanna Liebl
- Department of Pharmacy, Pharmaceutical Biology, Ludwig Maximilians University Münich, Butenandtstrasse 5-13, 81377 Münich, Germany
| | - Stefan Zahler
- Department of Pharmacy, Pharmaceutical Biology, Ludwig Maximilians University Münich, Butenandtstrasse 5-13, 81377 Münich, Germany
| | - Amedeo Caflisch
- Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
| | - Cristina Nevado
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
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Zhang S, Menche D, Zahler S, Vollmar AM, Liebl J, Förster F. In vitro anti-cancer effects of the actin-binding natural compound rhizopodin. Pharmazie 2015; 70:610-615. [PMID: 26492647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Several natural compound interfere with microtubules or the actin cytoskeleton. Compounds interfering with the microtubules like Vinca-alkaloids or taxanes, are extensively used for cancer therapy. In contrast, knowledge about pharmacological properties of actin binding drugs is poor and drugs interfering with actin are far from clinical use. Rhizopodin is a natural compound that strongly affects the actin cytoskeleton at nanomolar concentrations. Initial work revealed interesting anti-bacterial and cytotoxic effects, but the cellular effects and pharmacological properties of rhizopodin have not been characterized. We hypothesized that rhizopodin might exert anti-cancer activity. Therefore, the aim of this study was to characterize the cellular and pharmacological effects of rhizopodin in cancer. Effects of rhizopodin demonstrated prominent effects on the actin cytoskeleton as shown in the actin-pyrene assay and by immunostaining of cancer cells. To investigate cellular effects of rhizopodin, we analyzed cell proliferation, cell death induction by propidium iodide exclusion and western blot, as well as migration by impedance measurement using the xCELLligence device in MDA-MB-231 breast cancer and T24 bladder cancer cell lines. Rhizopodin inhibited proliferation and induced cell death of MDA-MB-231 and T24 cells at nanomolar concentrations. PARP cleavage by rhizopodin suggests caspase-dependent cell death induction. Importantly, rhizopodin potently inhibited MDA-MB-231 and T24 cancer cell migration at subtoxic doses where no actin aggregation was observed, indicating a specific underlying signaling of rhizopodin. In summary, our study elucidates rhizopodin as actin-binding natural compound that exerts potent anti-cancer effects. Therefore, our work provides the basis for further in depth characterization of rhizopodin as an antitumoral agent.
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Ehrlich SM, Liebl J, Ardelt MA, Lehr T, De Toni EN, Mayr D, Brandl L, Kirchner T, Zahler S, Gerbes AL, Vollmar AM. Targeting cyclin dependent kinase 5 in hepatocellular carcinoma--A novel therapeutic approach. J Hepatol 2015; 63:102-13. [PMID: 25660209 DOI: 10.1016/j.jhep.2015.01.031] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/17/2014] [Accepted: 01/27/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS For a long time cyclin dependent kinase 5 (Cdk5) was thought to be exclusively important in neuronal cells. However, increasing evidence recently suggests a function of Cdk5 in cancer progression. In this study, we examined the role of Cdk5 and its therapeutic accessibility in hepatocellular carcinoma (HCC), a highly chemoresistant cancer with poor prognosis and paramount clinical importance in order to develop novel targeted therapies for systemic treatment. METHODS Expression and activity of Cdk5 was analyzed in a human HCC tissue microarray, human patient samples and HCC cell lines. To characterize Cdk5 functions and signaling pathways in HCC, we applied genetic downregulation and pharmacologic inhibition in various approaches including cell based assays and mouse xenograft models. RESULTS Expression and activity of Cdk5 was increased in human HCC tissues as compared to normal liver tissues. Functional ablation of Cdk5 significantly decreased HCC cell proliferation and clonogenic survival. Moreover, genetic and pharmacological inhibition of Cdk5 showed in vivo efficacy in HCC xenograft mouse models. Investigating the mechanisms behind these functional effects revealed that Cdk5 is most active in the nucleus of cells in G2/M phase. Cdk5 regulates DNA damage response by phosphorylating ataxia telangiectasia mutated (ATM) kinase and thereby influencing its downstream cascade. Consequently, combination of Cdk5 inhibition with DNA-damage-inducing chemotherapeutics synergistically inhibited HCC tumor progression in vitro and in vivo. CONCLUSIONS In summary, we introduce Cdk5 as a novel drugable target for HCC treatment and suggest the combination of Cdk5 inhibition and DNA damaging agents as a novel therapeutic approach.
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Affiliation(s)
- Sandra M Ehrlich
- Department of Pharmacy, Pharmaceutical Biology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Johanna Liebl
- Department of Pharmacy, Pharmaceutical Biology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Maximilian A Ardelt
- Department of Pharmacy, Pharmaceutical Biology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Thorsten Lehr
- Clinical Pharmacy, Saarland University, Saarbrücken, Germany
| | - Enrico N De Toni
- Department of Internal Medicine II, Liver Center Munich®, Hospital of the Ludwig Maximilians University of Munich, Campus Grosshadern, Munich, Germany
| | - Doris Mayr
- Institute of Pathology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Lydia Brandl
- Institute of Pathology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Thomas Kirchner
- Institute of Pathology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Stefan Zahler
- Department of Pharmacy, Pharmaceutical Biology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Alexander L Gerbes
- Department of Internal Medicine II, Liver Center Munich®, Hospital of the Ludwig Maximilians University of Munich, Campus Grosshadern, Munich, Germany
| | - Angelika M Vollmar
- Department of Pharmacy, Pharmaceutical Biology, Ludwig Maximilians University of Munich, Munich, Germany.
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Schneider LS, von Schwarzenberg K, Lehr T, Ulrich M, Kubisch-Dohmen R, Liebl J, Trauner D, Menche D, Vollmar AM. Vacuolar-ATPase Inhibition Blocks Iron Metabolism to Mediate Therapeutic Effects in Breast Cancer. Cancer Res 2015; 75:2863-74. [DOI: 10.1158/0008-5472.can-14-2097] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 04/28/2015] [Indexed: 11/16/2022]
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Menhofer MH, Bartel D, Liebl J, Kubisch R, Busse J, Wagner E, Müller R, Vollmar AM, Zahler S. In vitro and in vivo characterization of the actin polymerizing compound chondramide as an angiogenic inhibitor. Cardiovasc Res 2014; 104:303-14. [PMID: 25239826 DOI: 10.1093/cvr/cvu210] [Citation(s) in RCA: 3] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
AIMS Inhibiting angiogenesis is a major approach in tumour therapy. To combat angiogenesis, the tubulin cytoskeleton has emerged as an interesting target in many pre- and clinical studies. Contrarily, the actin cytoskeleton has been largely neglected as a potential drug target in angiogenesis. However, due to the development of drug resistances, new therapeutic strategies are always needed in tumour treatment. Therefore, the therapeutic potential of actin-binding small molecules is of particular interest. METHODS AND RESULTS We investigate the impact of chondramide (Ch), an actin polymerizing myxobacterial compound, on angiogenesis and underlying signalling. Chondramide treatment not only reduces the migration of endothelial cells but also the maturation of endothelial tube networks on matrigel. These observations can partly be explained by a disintegration of stress fibres due to aggregation and subsequent accumulation of actin in cellular structures known as 'aggresomes'. Chondramide treatment impairs the maturation of focal adhesions and reduces the amount of active β1 integrin at the cell surface. Accordingly, signalling events downstream of focal adhesions are reduced. Thus, we observed that the activity of Src and downstream factors Rho-GTPases Rac1 and Rho is reduced upon Ch treatment. In vivo, Ch was well tolerated in mice and vascularization of a tumour xenograft as well as of the developing retina was significantly reduced. CONCLUSION Chondramide diminishes angiogenesis via two ways: (i) the disintegration of stress fibres and (ii) the reduction of promigratory signals. Our findings highlight Ch as a novel class of therapeutic lead compound with anti-angiogenic potential.
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Affiliation(s)
- Magdalena H Menhofer
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Dominik Bartel
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Johanna Liebl
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Rebekka Kubisch
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Johanna Busse
- Department of Pharmacy, Pharmaceutical Biotechnology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Ernst Wagner
- Department of Pharmacy, Pharmaceutical Biotechnology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Rolf Müller
- Helmholtz Institute for Pharmaceutical Research Saarland, Helmholtz Centre for Infection Research and Department of Pharmaceutical Biotechnology, Saarland University, Saarbrücken, Germany
| | - Angelika M Vollmar
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Stefan Zahler
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, Munich 81377, Germany
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Liebl J, Paganetti H, Winey B. SU-E-T-324: The Influence of Patient Positioning Uncertainties in Proton Radiotherapy On Proton Range and Dose Distributions. Med Phys 2014. [DOI: 10.1118/1.4888657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Braig S, Wiedmann RM, Liebl J, Singer M, Kubisch R, Schreiner L, Abhari BA, Wagner E, Kazmaier U, Fulda S, Vollmar AM. Pretubulysin: a new option for the treatment of metastatic cancer. Cell Death Dis 2014; 5:e1001. [PMID: 24434509 PMCID: PMC4040707 DOI: 10.1038/cddis.2013.510] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 11/19/2013] [Accepted: 11/20/2013] [Indexed: 01/19/2023]
Abstract
Tubulin-binding agents such as taxol, vincristine or vinblastine are well-established drugs in clinical treatment of metastatic cancer. However, because of their highly complex chemical structures, the synthesis and hence the supply issues are still quite challenging. Here we set on stage pretubulysin, a chemically accessible precursor of tubulysin that was identified as a potent microtubule-binding agent produced by myxobacteria. Although much simpler in chemical structure, pretubulysin abrogates proliferation and long-term survival as well as anchorage-independent growth, and also induces anoikis and apoptosis in invasive tumor cells equally potent to tubulysin. Moreover, pretubulysin posseses in vivo efficacy shown in a chicken chorioallantoic membrane (CAM) model with T24 bladder tumor cells, in a mouse xenograft model using MDA-MB-231 mammary cancer cells and finally in a model of lung metastasis induced by 4T1 mouse breast cancer cells. Pretubulysin induces cell death via the intrinsic apoptosis pathway by abrogating the expression of pivotal antiapoptotic proteins, namely Mcl-1 and Bcl-xL, and shows distinct chemosensitizing properties in combination with TRAIL in two- and three-dimensional cell culture models. Unraveling the underlying signaling pathways provides novel information: pretubulysin induces proteasomal degradation of Mcl-1 by activation of mitogen-activated protein kinase (especially JNK (c-Jun N-terminal kinase)) and phosphorylation of Mcl-1, which is then targeted by the SCFFbw7 E3 ubiquitin ligase complex for ubiquitination and degradation. In sum, we designate the microtubule-destabilizing compound pretubulysin as a highly promising novel agent for mono treatment and combinatory treatment of invasive cancer.
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Affiliation(s)
- S Braig
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - R M Wiedmann
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - J Liebl
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - M Singer
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - R Kubisch
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - L Schreiner
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - B A Abhari
- Institute for Experimental Research in Pediatrics, University Hospital Frankfurt, Komturstrasse 3a, 60528 Frankfurt aM, Germany
| | - E Wagner
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - U Kazmaier
- Institute for Organic Chemistry, Saarland University, PO Box 151150, 66041 Saarbrücken, Germany
| | - S Fulda
- Institute for Experimental Research in Pediatrics, University Hospital Frankfurt, Komturstrasse 3a, 60528 Frankfurt aM, Germany
| | - A M Vollmar
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstrasse 5-13, 81377 Munich, Germany
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14
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Liebl J, Testa M, Lu H, Winey B, Grogg K, Zhu X, El Fakhri G, Paganetti H. OC-0268: Uncertainties in PET-based range verification of pristine and spread-out Bragg peaks of clinical proton therapy. Radiother Oncol 2014. [DOI: 10.1016/s0167-8140(15)30373-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Rath S, Liebl J, Fürst R, Vollmar AM, Zahler S. Regulation of endothelial signaling and migration by v-ATPase. Angiogenesis 2013; 17:587-601. [PMID: 24254321 DOI: 10.1007/s10456-013-9408-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 11/12/2013] [Indexed: 01/04/2023]
Abstract
The vacuolar ATPase (v-ATPase) is a proton pump, able to acidify intracellular compartments and the pericellular space. v-ATPase has extensively been studied in various functional contexts, e.g., migration of tumor cells, and inhibition of v-ATPase has been proven as intriguing novel therapeutic concept. Since the role of v-ATPase in endothelial cell migration and angiogenesis has scarcely been investigated, we examined the consequences of pharmacological inhibition of v-ATPase (by concanamycin) on proliferation, migration, VEGF-receptor 2 (VEGFR2) trafficking and signaling, as well as Notch-mediated transcription in endothelial cells [human microvascular endothelial cells (HMEC-1) and human umbilical vein endothelial cells (HUVEC)] Treatment of the cells with 3 or 10 nM of the v-ATPase inhibitor concanamycin for 48 h or longer inhibited proliferation and arrested cell cycle in the G2/M phase in HMEC-1, while a G1 phase arrest occurred in HUVEC. Already after 24 h these concentrations reduced migration (scratch assay, chemotactic gradient). Activation of the small GTPase Rac1 in freshly adherent cells was reduced by concanamycin. Downstream signaling of the VEGFR2 (phosphorylation of ERK1/2 and AKT), as well as autophosphorylation of VEGFR2 were inhibited. VEGFR2 on the cell surface was reduced, and sequestered in a lysosomal compartment. In addition, concanamycin blocked transcription of the Notch target genes Hey1 and Hey2 after stimulation with DLL4. Since the impaired signaling pathways (Rac-1, VEGFR2, Notch) all depend on vesicular recycling circuits, we conclude that the disturbance of these is the main mode of action of v-ATPase inhibition in endothelial cells, offering an attractive multi-factorial anti-angiogenic approach.
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Affiliation(s)
- Sebastian Rath
- Department of Pharmacy, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, Munich, Germany
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16
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17
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Rath S, Liebl J, Fürst R, Ullrich A, Burkhart JL, Kazmaier U, Herrmann J, Müller R, Günther M, Schreiner L, Wagner E, Vollmar AM, Zahler S. Anti-angiogenic effects of the tubulysin precursor pretubulysin and of simplified pretubulysin derivatives. Br J Pharmacol 2013; 167:1048-61. [PMID: 22595030 DOI: 10.1111/j.1476-5381.2012.02037.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE The use of tubulin-binding compounds, which act in part by inhibiting tumour angiogenesis, has become an integral strategy of tumour therapy. Recently, tubulysins were identified as a novel class of natural compounds of myxobacterial origin, which inhibit tubulin polymerization. As these compounds are structurally highly complex, the search for simplified precursors [e.g. pretubulysin (Prt)] and their derivatives is mandatory to overcome supply problems hampering clinical development. We tested the anti-angiogenic efficacy of Prt and seven of its derivatives in comparison to tubulysin A (TubA). EXPERIMENTAL APPROACH The compounds were tested in cellular angiogenesis assays (proliferation, cytotoxicity, cell cycle, migration, chemotaxis, tube formation) and in vitro (tubulin polymerization). The efficacy of Prt was also tested in vivo in a murine subcutaneous tumour model induced with HUH7 cells; tumour size and vascularization were measured. KEY RESULTS The anti-angiogenic potency of all the compounds tested ran parallel to their inhibition of tubulin polymerization in vitro. Prt showed nearly the same efficacy as TubA (EC(50) in low nanomolar range in all cellular assays). Some modifications in the Prt molecule caused only a moderate drop in potency, while others resulted in a dramatic loss of action, providing initial insight into structure-activity relations. In vivo, Prt completely prevented tumour growth and reduced vascular density to 30%. CONCLUSIONS AND IMPLICATIONS Prt, a chemically accessible precursor of some tubulysins is a highly attractive anti-angiogenic compound both in vitro and in vivo. Even more simplified derivatives of this compound still retain high anti-angiogenic efficacy.
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Affiliation(s)
- S Rath
- Department of Pharmacy--Center for Drug Research, Butenandtstr, 5-13, 81377 Munich, Germany.
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18
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Weitensteiner SB, Liebl J, Krystof V, Havlíček L, Gucký T, Strnad M, Fürst R, Vollmar AM, Zahler S. Trisubstituted pyrazolopyrimidines as novel angiogenesis inhibitors. PLoS One 2013; 8:e54607. [PMID: 23336010 PMCID: PMC3545992 DOI: 10.1371/journal.pone.0054607] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 12/14/2012] [Indexed: 02/07/2023] Open
Abstract
Current inhibitors of angiogenesis comprise either therapeutic antibodies (e.g. bevacicumab binding to VEGF-A) or small molecular inhibitors of receptor tyrosin kinases like e.g. sunitinib, which inhibits PDGFR and VEGFR. We have recently identified cyclin-dependent kinase 5 (Cdk5) as novel alternative and pharmacologically accessible target in the context of angiogenesis. In the present work we demonstrate that trisubstituted pyrazolo[4,3-d]pyrimidines constitute a novel class of compounds which potently inhibit angiogenesis. All seven tested compounds inhibited endothelial cell proliferation with IC50 values between 1 and 18 µM. Interestingly, this seems not to be due to cytotoxicity, since none of them showed acute cytotoxic effects on endothelial cells at a concentration of 10 µM,. The three most potent compounds (LGR1404, LGR1406 and LGR1407) also inhibited cell migration (by 27, 51 and 31%, resp.), chemotaxis (by 50, 70 and 60% in accumulative distance, resp.), and tube formation (by 25, 60 and 30% of total tube length, resp.) at the non-toxic concentration of 10 µM. Furthermore, angiogenesis was reduced in vivo in the CAM assay by these three compounds. A kinase selectivity profiling revealed that the compounds prevalently inhibit Cdk2, Cdk5 and Cdk9. The phenotype of the migrating cells (reduced formation of lamellipodia, loss of Rac-1 translocation to the membrane) resembles the previously described effects of silencing of Cdk5 in endothelial cells. We conclude that especially LGR1406 and LGR1407 are highly attractive anti-angiogenic compounds, whose effects seem to largely depend on their Cdk5 inhibiting properties.
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Affiliation(s)
| | - Johanna Liebl
- Department of Pharmacy, Ludwig-Maximilians-University, Munich, Germany
| | - Vladimir Krystof
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany AS CR, Olomouc, Czech Republic
| | - Libor Havlíček
- Isotope Laboratory, Institute of Experimental Botany AS CR, Prague, Czech Republic
| | - Tomáš Gucký
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany AS CR, Olomouc, Czech Republic
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Department of Growth Regulators, Palacký University, Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany AS CR, Olomouc, Czech Republic
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Department of Growth Regulators, Palacký University, Olomouc, Czech Republic
| | - Robert Fürst
- Department of Pharmacy, Ludwig-Maximilians-University, Munich, Germany
| | | | - Stefan Zahler
- Department of Pharmacy, Ludwig-Maximilians-University, Munich, Germany
- * E-mail:
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Rárová L, Zahler S, Liebl J, Kryštof V, Sedlák D, Bartůněk P, Kohout L, Strnad M. Brassinosteroids inhibit in vitro angiogenesis in human endothelial cells. Steroids 2012; 77:1502-9. [PMID: 22974826 DOI: 10.1016/j.steroids.2012.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/01/2012] [Accepted: 08/08/2012] [Indexed: 01/04/2023]
Abstract
Antiangiogenic activity of the brassinosteroid plant hormones (BRs) and their derivative cholestanon was investigated in human umbilical vein endothelial cells (HUVEC) and in human microvascular endothelial cells (HMEC-1). 24-Epibrassinolide and 28-homocastasterone from group of 21 tested natural BRs inhibited migration of HUVEC cells. Seven tested BRs decreased the number of tubes significantly. Synthetic analogue cholestanon inhibited angiogenesis in vitro more effectively than natural BRs. Because of the similarity of BRs to human steroids, we have also studied interactions of BRs with human steroid receptors. Synthetic BRs cholestanon showed agonistic effects on estrogen-receptor-α, estrogen-receptor-β and androgen receptor. Of the natural BRs, 24-epibrassinolide was found to be a weak antagonist of estrogen-receptor-α (ERα). Our results provide the first evidence that large group of BRs can inhibit in vitro angiogenesis of primary endothelial cells. BRs constitute a novel group of human steroid receptor activators or inhibitors with capacity to inhibit angiogenesis.
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Affiliation(s)
- Lucie Rárová
- Centre of Region Haná for Biotechnological and Agricultural Research, Department of Growth Regulators, Faculty of Science, Palacký University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic
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20
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Wiedmann RM, von Schwarzenberg K, Palamidessi A, Schreiner L, Kubisch R, Liebl J, Schempp C, Trauner D, Vereb G, Zahler S, Wagner E, Müller R, Scita G, Vollmar AM. The V-ATPase-inhibitor archazolid abrogates tumor metastasis via inhibition of endocytic activation of the Rho-GTPase Rac1. Cancer Res 2012; 72:5976-87. [PMID: 22986742 DOI: 10.1158/0008-5472.can-12-1772] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The abundance of the multimeric vacuolar ATP-dependent proton pump, V-ATPase, on the plasma membrane of tumor cells correlates with the invasiveness of the tumor cell, suggesting the involvement of V-ATPase in tumor metastasis. V-ATPase is hypothesized to create a proton efflux leading to an acidic pericellular microenvironment that promotes the activity of proinvasive proteases. An alternative, not yet explored possibility is that V-ATPase regulates the signaling machinery responsible for tumor cell migration. Here, we show that pharmacologic or genetic reduction of V-ATPase activity significantly reduces migration of invasive tumor cells in vitro. Importantly, the V-ATPase inhibitor archazolid abrogates tumor dissemination in a syngeneic mouse 4T1 breast tumor metastasis model. Pretreatment of cancer cells with archazolid impairs directional motility by preventing spatially restricted, leading edge localization of epidermal growth factor receptor (EGFR) as well as of phosphorylated Akt. Archazolid treatment or silencing of V-ATPase inhibited Rac1 activation, as well as Rac1-dependent dorsal and peripheral ruffles by inhibiting Rab5-mediated endocytotic/exocytotic trafficking of Rac1. The results indicate that archazolid effectively decreases metastatic dissemination of breast tumors by impairing the trafficking and spatially restricted activation of EGFR and Rho-GTPase Rac1, which are pivotal for directed movement of cells. Thus, our data reveals a novel mechanism underlying the role of V-ATPase in tumor dissemination.
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Affiliation(s)
- Romina M Wiedmann
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
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21
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Regel I, Eichenmüller M, Joppien S, Liebl J, Häberle B, Müller-Höcker J, Vollmar A, von Schweinitz D, Kappler R. IGFBP3 impedes aggressive growth of pediatric liver cancer and is epigenetically silenced in vascular invasive and metastatic tumors. Mol Cancer 2012; 11:9. [PMID: 22401581 PMCID: PMC3349592 DOI: 10.1186/1476-4598-11-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 03/08/2012] [Indexed: 12/16/2022] Open
Abstract
Background Hepatoblastoma (HB) is an embryonal liver neoplasm of early childhood with a poor prognosis for patients with distant metastases and vascular invasion. We and others have previously shown that the overexpression of insulin-like growth factor 2 (IGF2), loss of imprinting at the IGF2/H19 locus, and amplification of pleomorphic adenoma gene 1 (PLAG1) are common features in HB, suggesting a critical role of the IGF axis in hepatoblastomagenesis. In this study, we investigated the role of the insulin-like growth factor binding protein 3 (IGFBP3), a known competitor of the IGF axis, in pediatric liver cancers. Results The IGFBP3 gene was highly expressed in normal pediatric livers but was heavily downregulated in four HB cell lines and the majority of HB primary tumors (26/36). Detailed methylation analysis of CpG sites in the IGFBP3 promoter region by bisulfite sequencing revealed a high degree of DNA methylation, which is causatively associated with the suppression of IGFBP3 in HB cell lines. Consequently, the treatment of HB cell lines with 5-aza-2'-deoxycytidine resulted in DNA demethylation and reactivation of the epigenetically silenced IGFBP3 expression. Interestingly, IGFBP3 promoter methylation predominantly occurred in metastatic HB with vascular invasion. Restoring IGFBP3 expression in HB cells resulted in reduced colony formation, migration, and invasion. Conclusion This study provides the first direct evidence that the reactivation of IGFBP3 decreases aggressive properties of pediatric liver cancer cells and that IGFBP3 promoter methylation might be used as an indicator for vessel-invasive tumor growth in HB patients.
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Affiliation(s)
- Ivonne Regel
- Department of Pediatric Surgery, Dr, von Hauner Children's Hospital, Ludwig-Maximilians-University Munich, 80337 Munich, Federal Republic of Germany
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22
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Kryštof V, Rárová L, Liebl J, Zahler S, Jorda R, Voller J, Cankař P. The selective P-TEFb inhibitor CAN508 targets angiogenesis. Eur J Med Chem 2011; 46:4289-94. [PMID: 21777997 DOI: 10.1016/j.ejmech.2011.06.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 06/20/2011] [Accepted: 06/27/2011] [Indexed: 10/18/2022]
Abstract
Small molecule inhibitors of cyclin-dependent kinases (CDK) have been developed as anticancer drugs with cytostatic and cytotoxic properties, but some of them have also been shown to limit angiogenesis. Here, we report that the 3,5-diaminopyrazole CAN508 inhibits endothelial cell migration and tube formation. In addition, it reduces phosphorylation of the C-terminus of RNA polymerase II and inhibits mRNA synthesis in endothelial cells, in accordance with previous observations that it has high selectivity towards the positive transcriptional regulator P-TEFb. Moreover, CAN508 reduces expression of vascular endothelial growth factor by several human cancer cell lines. The findings suggest that P-TEFb may be an attractive target for anti-angiogenic therapy.
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Affiliation(s)
- Vladimír Kryštof
- Laboratory of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 11, 783 71 Olomouc, Czech Republic.
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23
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Liebl J, Krystof V, Vereb G, Takács L, Strnad M, Pechan P, Havlicek L, Zatloukal M, Fürst R, Vollmar AM, Zahler S. Anti-angiogenic effects of purine inhibitors of cyclin dependent kinases. Angiogenesis 2011; 14:281-91. [DOI: 10.1007/s10456-011-9212-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 03/31/2011] [Indexed: 01/23/2023]
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24
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Liebl J, Weitensteiner SB, Vereb G, Takács L, Fürst R, Vollmar AM, Zahler S. Cyclin-dependent kinase 5 regulates endothelial cell migration and angiogenesis. J Biol Chem 2010; 285:35932-43. [PMID: 20826806 DOI: 10.1074/jbc.m110.126177] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Angiogenesis contributes to various pathological conditions. Due to the resistance against existing antiangiogenic therapy, an urgent need exists to understand the molecular basis of vessel growth and to identify new targets for antiangiogenic therapy. Here we show that cyclin-dependent kinase 5 (Cdk5), an important modulator of neuronal processes, regulates endothelial cell migration and angiogenesis, suggesting Cdk5 as a novel target for antiangiogenic therapy. Inhibition or knockdown of Cdk5 reduces endothelial cell motility and blocks angiogenesis in vitro and in vivo. We elucidate a specific signaling of Cdk5 in the endothelium; in contrast to neuronal cells, the motile defects upon inhibition of Cdk5 are not caused by an impaired function of focal adhesions or microtubules but by the reduced formation of lamellipodia. Inhibition or down-regulation of Cdk5 decreases the activity of the small GTPase Rac1 and results in a disorganized actin cytoskeleton. Constitutive active Rac1 compensates for the inhibiting effects of Cdk5 knockdown on migration, suggesting that Cdk5 exerts its effects in endothelial cell migration via Rac1. Our work elucidates Cdk5 as a pivotal new regulator of endothelial cell migration and angiogenesis. It suggests Cdk5 as a novel, pharmacologically accessible target for antiangiogenic therapy and provides the basis for a new therapeutic application of Cdk5 inhibitors as antiangiogenic agents.
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Affiliation(s)
- Johanna Liebl
- Center for Drug Research, Pharmaceutical Biology, Ludwig-Maximilians-University, 81377 Munich, Germany
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25
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Zahler S, Liebl J, Fürst R, Vollmar AM. Anti-angiogenic potential of small molecular inhibitors of cyclin dependent kinases in vitro. Angiogenesis 2010; 13:239-49. [PMID: 20706783 DOI: 10.1007/s10456-010-9181-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 08/03/2010] [Indexed: 01/09/2023]
Abstract
Small molecular kinase inhibitors are promising novel drugs. Initially, they were designed for the highest possible specificity. Recently, this concept has been challenged by multikinase inhibitors, which are clinically more potent. This change of paradigm calls for re-examination of already known compounds in different functional contexts. We have compared 6 reported structurally different inhibitors of cyclin-dependent kinases (Cdks) regarding their functional effects on endothelial cells (proliferation, cell cycle, apoptosis, migration, tube formation), as well as their actions on some kinases (AKT, p38, ERK1/2, c-src, GSK3β). Only some of these compounds had anti-angiogenic effects in concentrations up to 10 μM (aminopurvalanol, indirubin-3'-monoxime, and alsterpaullone), depending on their kinase profile. Interestingly, the impact of the compounds on Cdks seemed to be of minor importance, as compared to other mechanisms. Aminopurvalanol, indirubin-3'-monoxime, and alsterpaullone might turn out as interesting scaffolds for the development of novel anti-angiogenic drugs.
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Affiliation(s)
- Stefan Zahler
- Department of Pharmacy, Center for System Based Drug Research, University of Munich, Butenandtstr. 5-13, 81377 Munich, Germany.
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26
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Koltermann A, Liebl J, Fürst R, Ammer H, Vollmar AM, Zahler S. Ginkgo biloba extract EGb 761 exerts anti-angiogenic effects via activation of tyrosine phosphatases. J Cell Mol Med 2008; 13:2122-2130. [PMID: 19175691 DOI: 10.1111/j.1582-4934.2008.00561.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The standardised Ginkgo biloba extract EGb 761 (Dr. Willmar Schwabe Pharmaceuticals, Karlsruhe, Germany) is one of the most widely used herbal remedies. Indications for this extract range from dementia to peripheral vascular disease, based on well-documented vascular effects. Surprisingly, the actions of EGb 761 on angiogenesis as a function of vascular cells have not been investigated to date. The anti-cancer activity of EGb 761 in vitro and epidemiological data showing reduced risk for ovarian cancer in regular users have prompted us to investigate this issue. We show an anti-angiogenic profile of EGb 761 in vitro (inhibited proliferation, migration and tube formation of endothelial cells) and in vivo in the chicken chorio-allantoic membrane (CAM) assay. An analysis of the underlying mechanisms indicates inhibition of growth factor-induced extracellular signal-regulated kinase (ERK) phosphorylation by EGb 761. Inhibitory effects of EGb 761 on ERK as well as of the upstream kinases map-erk-kinase (MEK) and rapidly growing fibrosarcoma (Raf)-1 could be completely reversed by pre-treatment with sodium vanadate (inhibitor of tyrosine phosphatases). Sodium vanadate also reversed the EGb 761-induced inhibition of endothelial cell migration. Focusing on tyrosine phosphatases upstream of the Raf-MEK-ERK cascade, we identified the tyrosine phosphatase Src homology-2 domain-containing phosphatase 1 (SHP-1) as one target of EGb 761. SHP-1 was rapidly activated by EGb 761, and silencing SHP-1 (siRNA) abrogated reduction of endothelial proliferation by EGb 761. In summary, we identify EGb 761 as a potent anti-angiogenic drug. The underlying mechanism is the activation of protein tyrosine phosphatases, leading to inhibition of the Raf-MEK-ERK pathway. These findings provide a rational basis for using EGb 761 for an additional therapeutic indication: anti-angiogenesis-based tumour prevention and adjuvant therapy.
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Affiliation(s)
- Anja Koltermann
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Johanna Liebl
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Robert Fürst
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Hermann Ammer
- Institute of Pharmacology, Toxicology and Pharmacy, University of Munich, Munich, Germany
| | - Angelika M Vollmar
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
| | - Stefan Zahler
- Department of Pharmacy, Pharmaceutical Biology, University of Munich, Munich, Germany
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