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Telomere Transcripts Target Telomerase in Human Cancer Cells. Genes (Basel) 2016; 7:genes7080046. [PMID: 27537914 PMCID: PMC4999834 DOI: 10.3390/genes7080046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/24/2016] [Accepted: 07/29/2016] [Indexed: 12/14/2022] Open
Abstract
Long non-coding transcripts from telomeres, called telomeric repeat-containing RNA (TERRA), were identified as blocking telomerase activity (TA), a telomere maintenance mechanism (TMM), in tumors. We expressed recombinant TERRA transcripts in tumor cell lines with TA and with alternative lengthening of telomeres (ALT) to study effects on TMM and cell growth. Adeno- and lentivirus constructs (AV and LV) were established for transient and stable expression of approximately 130 units of telomere hexanucleotide repeats under control of cytomegalovirus (CMV) and human RNase P RNA H1 (hH1) promoters with and without polyadenylation, respectively. Six human tumor cell lines either using telomerase or ALT were infected and analyzed for TA levels. Pre-infection cells using telomerase had 1%-3% of the TERRA expression levels of ALT cells. AV and LV expression of recombinant TERRA in telomerase positive cells showed a 1.3-2.6 fold increase in TERRA levels, and a decrease in TA of 25%-58%. Dominant-negative or small hairpin RNA (shRNA) viral expression against human telomerase reverse transcriptase (hTERT) results in senescence, not induced by TERRA expression. Population doubling time, cell viability and TL (telomere length) were not impacted by ectopic TERRA expression. Clonal growth was reduced by TERRA expression in TA but not ALT cell lines. ALT cells were not affected by treatments applied. Established cell models and tools may be used to better understand the role of TERRA in the cell, especially for targeting telomerase.
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Paur J, Nika L, Maier C, Moscu-Gregor A, Kostka J, Huber D, Mohr T, Heffeter P, Schrottmaier WC, Kappel S, Kandioler D, Holzmann K, Marian B, Berger W, Grusch M, Grasl-Kraupp B. Fibroblast growth factor receptor 3 isoforms: Novel therapeutic targets for hepatocellular carcinoma? Hepatology 2015; 62:1767-78. [PMID: 26235436 DOI: 10.1002/hep.28023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 07/29/2015] [Indexed: 12/21/2022]
Abstract
UNLABELLED Fibroblast growth factor receptors (FGFRs) are frequently up-regulated in subsets of hepatocellular carcinoma (HCC). Here, we provide mechanistic insight that FGFR3 splice variants IIIb and IIIc impact considerably on the malignant phenotype of HCC cells. The occurrence of FGFR3 variants was analyzed in human HCC samples. In hepatoma/hepatocarcinoma cell lines, FGFR3 isoforms were overexpressed by lentiviral constructs or down-modulated by small interfering RNA (siRNA; affecting FGFR3-IIIb and -IIIc) or an adenoviral kinase-dead FGFR3-IIIc construct (kdFGFR3). Elevated levels of FGFR3-IIIb and/or -IIIc were found in 53% of HCC cases. FGFR3-IIIb overexpression occurred significantly more often in primary tumors of large (pT2-4) than of small size (pT1). Furthermore, one or both isoforms were enhanced mostly in cases with early tumor infiltration and/or recurrence at the time of surgery or follow-up examinations. In hepatoma/hepatocarcinoma cells, up-regulated FGFR3-IIIb conferred an enhanced capability for proliferation. Both FGFR3-IIIb and FGFR3-IIIc suppressed apoptotic activity, enhanced clonogenic growth, and induced disintegration of the blood/lymph endothelium. The tumorigenicity of cells in severe combined immunodeficiency mice was augmented to a larger degree by variant IIIb than by IIIc. Conversely, siRNA targeting FGFR3 and kdFGFR3 reduced clonogenicity, anchorage-independent growth, and disintegration of the blood/lymph endothelium in vitro. Furthermore, kdFGFR3 strongly attenuated tumor formation in vivo. CONCLUSIONS Deregulated FGFR3 variants exhibit specific effects in the malignant progression of HCC cells. Accordingly, blockade of FGFR3-mediated signaling may be a promising therapeutic approach to antagonize growth and malignant behavior of HCC cells.
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Affiliation(s)
- Jakob Paur
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Lisa Nika
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Christiane Maier
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Alexander Moscu-Gregor
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Julia Kostka
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Daniela Huber
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Thomas Mohr
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Petra Heffeter
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Waltraud C Schrottmaier
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Sonja Kappel
- Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - Daniela Kandioler
- Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - Klaus Holzmann
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Brigitte Marian
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Walter Berger
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Michael Grusch
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Bettina Grasl-Kraupp
- Department of Medicine I, Division: Institute of Cancer Research, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria
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Gauglhofer C, Paur J, Schrottmaier WC, Wingelhofer B, Huber D, Naegelen I, Pirker C, Mohr T, Heinzle C, Holzmann K, Marian B, Schulte-Hermann R, Berger W, Krupitza G, Grusch M, Grasl-Kraupp B. Fibroblast growth factor receptor 4: a putative key driver for the aggressive phenotype of hepatocellular carcinoma. Carcinogenesis 2014; 35:2331-8. [DOI: 10.1093/carcin/bgu151] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Lackner A, Kreidl E, Peter-Vörösmarty B, Spiegl-Kreinecker S, Berger W, Grusch M. Stable protein expression in mammalian cells using baculoviruses. Methods Mol Biol 2012; 801:75-92. [PMID: 21987248 DOI: 10.1007/978-1-61779-352-3_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The baculovirus Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) has been widely used in biotechnology for protein expression in insect cells. Baculoviruses use arthropods as their natural hosts and are unable to replicate in mammalian cells. However, AcMNPV is able to enter many mammalian cell types and can be used for transgene expression if engineered to contain suitable expression cassettes. In this chapter, we describe the construction and application of a recombinant baculovirus containing a bicistronic expression cassette that can be used for stable protein expression in mammalian cells. As an example, the generation of glioblastoma and hepatocellular carcinoma cell lines stably expressing green fluorescent protein after puromycin selection is shown.
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Affiliation(s)
- Andreas Lackner
- Department of Medicine I, Institute of Cancer Research, Medical University of Vienna, Vienna, Austria
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Fibroblast growth factor receptors as therapeutic targets in human melanoma: synergism with BRAF inhibition. J Invest Dermatol 2011; 131:2087-95. [PMID: 21753785 DOI: 10.1038/jid.2011.177] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cutaneous melanoma is a tumor with rising incidence and a very poor prognosis at the disseminated stage. Melanomas are characterized by frequent mutations in BRAF and also by overexpression of fibroblast growth factor 2 (FGF2), offering opportunities for therapeutic intervention. We investigated inhibition of FGF signaling and its combination with dacarbazine or BRAF inhibitors as an antitumor strategy in melanoma. The majority of melanoma cell lines displayed overexpression of FGF2 but also FGF5 and FGF18 together with different isoforms of FGF receptors (FGFRs) 1-4. Blockade of FGF signals with dominant-negative receptor constructs (dnFGFR1, 3, or 4) or small-molecule inhibitors (SU5402 and PD166866) reduced melanoma cell proliferation, colony formation, as well as anchorage-independent growth, and increased apoptosis. DnFGFR constructs also significantly inhibited tumor growth in vivo. Combination of FGF inhibitors with dacarbazine showed additive or antagonistic effects, whereas synergistic drug interaction was observed when combining FGFR inhibition with the multikinase/BRAF inhibitor sorafenib or the V600E mutant-specific BRAF inhibitor RG7204. In conclusion, FGFR inhibition has antitumor effects against melanoma cells in vitro and in vivo. Combination with BRAF inhibition offers a potential for synergistic antimelanoma effects and represents a promising therapeutic strategy against advanced melanoma.
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Microscopic analysis of adenoviral decontamination using GFP adenovirus with comparable sensitivity to flow cytometry. Methods Mol Biol 2009; 515:125-35. [PMID: 19378114 DOI: 10.1007/978-1-59745-559-6_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
Abstract
Expression of transgenes from adenovirus vectors has become an extremely important and widely used tool in experimental cancer research and many other areas in the life sciences. It needs to be kept in mind, however, that adenoviruses are human pathogens and avoiding exposure of laboratory personnel to infectious viral particles is therefore an important concern. This issue seems even more important when the transgenes expressed for experimental purposes include oncogenic sequences. Decontamination procedures are thus required, whenever laboratory experiments with adenovirus vectors are performed and the effectiveness of these procedures has to be established. While many reports exist on the decontamination of blood and pharmaceutical products, data on the stability of adenoviruses during experiments performed in most life science laboratories are very scarce. One reason for this is that many of the methods used for assessing viral decontamination are time consuming and laborious and cannot easily be incorporated into the broad range of experimental setups typically performed in the laboratory. In this chapter we describe a reliable, sensitive, and simple method for the assessment of adenovirus decontamination by the use of an adenovirus expressing green fluorescent protein (GFP). The GFP adenovirus is subjected to various test conditions and afterwards susceptible indicator cells are exposed to the recovered virions. GFP expression is detected by a combination of fluorescence microscopy and flow cytometry. The simplicity and flexibility of the method allows one to monitor viral decontamination during the different scenarios occurring in the life science laboratory.
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Lackner A, Genta K, Koppensteiner H, Herbacek I, Holzmann K, Spiegl-Kreinecker S, Berger W, Grusch M. A bicistronic baculovirus vector for transient and stable protein expression in mammalian cells. Anal Biochem 2008; 380:146-8. [PMID: 18541133 DOI: 10.1016/j.ab.2008.05.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 05/06/2008] [Accepted: 05/14/2008] [Indexed: 11/25/2022]
Abstract
Baculoviruses are widely used for protein production in insect cells, and their potential for gene transfer to mammalian cells is increasingly being recognized. Here we describe a baculovirus vector with a bicistronic mammalian expression cassette and demonstrate its suitability for efficient transient and stable protein expression in human glioblastoma cells. Bicistronic baculovirus vectors are safe, cost efficient, and easy to produce; thus, they represent an excellent gene transfer system for mammalian cells.
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Affiliation(s)
- Andreas Lackner
- Department of Medicine I, Institute of Cancer Research, Medical University of Vienna, A-1090 Vienna, Austria
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