gms | German Medical Science

61st Annual Meeting of the German Society of Neurosurgery (DGNC) as part of the Neurowoche 2010
Joint Meeting with the Brazilian Society of Neurosurgery on the 20 September 2010

German Society of Neurosurgery (DGNC)

21 - 25 September 2010, Mannheim

Proliferation of malignant glioma cells is significantly reduced after knockdown of Krüppel-like Factor 8 (KLF-8)

Meeting Abstract

  • Oliver Schnell - Neurochirurgische Klinik und Poliklinik, Klinikum der Ludwig-Maximilians-Universität München, Campus Großhadern, München, Deutschland
  • Alexander Romagna - Neurochirurgische Klinik und Poliklinik, Klinikum der Ludwig-Maximilians-Universität München, Campus Großhadern, München, Deutschland
  • Irene Jaehnert - Neurochirurgische Klinik und Poliklinik, Klinikum der Ludwig-Maximilians-Universität München, Campus Großhadern, München, Deutschland
  • Valerie Albrecht - Neurochirurgische Klinik und Poliklinik, Klinikum der Ludwig-Maximilians-Universität München, Campus Großhadern, München, Deutschland
  • Jörg-Christian Tonn - Neurochirurgische Klinik und Poliklinik, Klinikum der Ludwig-Maximilians-Universität München, Campus Großhadern, München, Deutschland
  • Christian Schichor - Neurochirurgische Klinik und Poliklinik, Klinikum der Ludwig-Maximilians-Universität München, Campus Großhadern, München, Deutschland

Deutsche Gesellschaft für Neurochirurgie. 61. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC) im Rahmen der Neurowoche 2010. Mannheim, 21.-25.09.2010. Düsseldorf: German Medical Science GMS Publishing House; 2010. DocV1543

DOI: 10.3205/10dgnc020, URN: urn:nbn:de:0183-10dgnc0209

Published: September 16, 2010

© 2010 Schnell 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: For glial tumor cells, the mechanisms used by integrins, especially αvβ3 integrin, to promote tumor cell proliferation are still a matter of discussion. Krüppel-like factor 8 (KLF-8) has been identified only recently as an integrin-dependent signaling molecule which stimulates cyclin D1 and subsequently G1/S-progression in mouse fibroblast NIH3T3 tumor cells. In the present study we investigate the expression and the functional impact of suspected downstream signaling molecules of αvβ3 integrin with special interest on KLF-8.

Methods: Sections and single tumor cells from primary diagnosed glioblastomas (WHO°IV, n=5) and low grade gliomas (WHO°II, n=5) as well as glioma cell line U87 MG were subjected to immunohistochemical and/or immunocytochemical staining for integrin αvβ3 and downstream signaling molecules: the phosphorylated focal adhesion kinase (pFAK), KLF-8 and cyclin D1. To determine whether these molecules are expressed in a WHO grade dependent manner we also performed Western blot analysis in the same entities (n=5 each). Additionally, quantitative PCR was carried out for integrin subunits αv and β3, KLF-8 and cyclin D1. For analysis of the functional impact of KLF-8 on cell cycle progression in gliomas, U87 MG were transduced with sh-RNA for KLF-8 knockdown.

Results: Integrin αvβ3 and the signaling molecules pFAK and cyclin D1 as well as the transcription factor KLF-8 could be detected in low grade gliomas and glioblastomas but were much more prominent in high grade gliomas as confirmed by Western blot analysis and immunohistochemistry. In U87 MG cells αvβ3-integrin and pFAK were found to be co-localised on cell membranes, whereas cyclin D1 and KLF-8 were detected preferentially in the nucleus of isolated cells. Transduction of U87 MG cells with sh-RNA-expressing adenoviral vectors at a low multiplicity of infection led to a >80% knockdown of KLF-8 mRNA as quantified by qRT-PCR. Moreover, preliminary data showed a reduction of the proliferation rate of KLF-8 knockdown – U87 MG cells of approximately 25% compared to cells transduced with a scrambled sh-RNA.

Conclusions: KLF-8 is expressed grade-dependently in glial brain tumors. Inhibiting downstream integrin signaling by blocking KLF-8 may represent a novel antiproliferative treatment strategy for malignant brain tumors.