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64th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

26 - 29 May 2013, Düsseldorf

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RNAi of bcl-2 in glioma cells is compatible with life and augments the efficiency of temozolomide treatment

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  • Achim Temme - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Carl Gustav Carus, TU Dresden,Dresden
  • Frederik Enders - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Carl Gustav Carus, TU Dresden,Dresden
  • Ralf Wiedemuth - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Carl Gustav Carus, TU Dresden,Dresden
  • Gabriele Schackert - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Carl Gustav Carus, TU Dresden,Dresden

Deutsche Gesellschaft für Neurochirurgie. 64. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Düsseldorf, 26.-29.05.2013. Düsseldorf: German Medical Science GMS Publishing House; 2013. DocP 143

doi: 10.3205/13dgnc560, urn:nbn:de:0183-13dgnc5604

Published: May 21, 2013

© 2013 Temme et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objective: The anti-apoptotic bcl-2 is considered as promising target to sensitize glioma cells for genotoxic drugs. We sought to analyze in detail the effects of stable bcl-2-RNAi on temozolomide (TMZ) treatment of glioma cells.

Method: U343-MG glioma cells harboring wild type p53 and U373-MG glioma cells with mutant p53 were transduced with retroviral vectors encoding for a shRNA targeting bcl-2. As controls we used cells which were transduced with a retroviral vector targeting luciferase. Transduced cells were treated with TMZ. Cell cycle as well as apoptosis was analyzed by SubG1-analysis and proteome profiler arrays.

Results: Knock down of bcl-2 protein did not substantially affect proliferation of glioma cells when compared to shLuc controls. Yet, in U343-MG-shBcl2 and U373-MG-shBcl2 cells TMZ-treatment led to a 2- and 4-fold increase in TRAIL R2/DR5 death receptor expression and concomitant increase in FADD when compared to non-treated controls. In shLuc transduced cells no increase in expression levels of death receptors after TMZ-treatment was noted. In addition U373-MG-shBCL-2 cells showed a twofold upregulation of pro-apoptotic Bax and Bad and a higher increase in the relative amount of cleaved caspase 3 when compared to U373-MG-shLuc cells. U343-MG-shBcl-2 as well as shLuc-transduced U343-MG cells showed activation of p53 after TMZ treatment whereas a concomitant 3-fold increase of pro-apoptotic smac/Diablo was only observed in U343-MG cells with knock down of bcl-2. FACS-analysis of TMZ-treated cells revealed a G2 arrest in all tested cell lines. Yet, analysis of the SubG1 fraction of TMZ-treated glioma cells with knock down of bcl-2 revealed a twofold increase in the fraction of apoptotic cells when compared to shLuc control cells.

Conclusions: Stable knock down of bcl-2 did not affect proliferation of glioma cells but sensitizes them to TMZ-treatment. In p53-wild type U343-MG cells TMZ-treatment likely induced a G2 arrest via activation of p53 whereas the molecular mechanism leading to a G2-arrest in U373-MG cells remains obscure.