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67. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Koreanischen Gesellschaft für Neurochirurgie (KNS)

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

12. - 15. Juni 2016, Frankfurt am Main

Proteolytic processing in the progression of low-grade astrocytomas to glioblastoma multiforme reveals a role for Calpains 1 and 2

Meeting Abstract

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  • Jörg W. Bartsch - Klinik für Neurochirurgie, Philipps-Universität Marburg, Marburg, Germany
  • Zon W. Lai - Institut für Molekulare Medizin und Zellforschung, Universität Freiburg, Freiburg, Germany
  • Christopher Nimsky - Klinik für Neurochirurgie, Philipps-Universität Marburg, Marburg, Germany
  • Oliver Schilling - Institut für Molekulare Medizin und Zellforschung, Universität Freiburg, Freiburg, Germany

Deutsche Gesellschaft für Neurochirurgie. 67. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 1. Joint Meeting mit der Koreanischen Gesellschaft für Neurochirurgie (KNS). Frankfurt am Main, 12.-15.06.2016. Düsseldorf: German Medical Science GMS Publishing House; 2016. DocP 031

doi: 10.3205/16dgnc406, urn:nbn:de:0183-16dgnc4063

Veröffentlicht: 8. Juni 2016

© 2016 Bartsch et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

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Objective: Global protein analytical techniques such as proteomics are powerful tools and advance our understanding of glioma biology. GBM accounts for more than half of all neoplasm of the brain with a poor prognosis and median survival rates of less than 15 months. Since GBM is strongly associated with deregulated proteolysis, this study aims to identify proteins altered in GBM vs. control brain as well as GBM vs. lower-grade gliomas. In addition, a method was employed to detect cleavage products of proteins derived by deregulated proteolysis.

Method: Regulation of key proteins as well as proteolytic cleavage events in non-malignant tissues of the brain, early stages from astrocytomas (lower grade, mainly II and III), and GBM grade IV was determined. Multiplexed analyses of extracted proteins from clinically dissected human tissues were carried out using isotopic labeling followed by two-dimensional liquid chromatography tandem mass spectrometry (LC-MS/MS). Differential abundance of proteins was confirmed by Western Blot, followed by functional assays in GBM cells using small interfering RNAs (siRNAs).

Results: More than 5600 proteins were identified and quantified, many of which are known to be involved in enhanced proteolysis and downsizing of neuronal functions such as synaptic transmission and neurological system processes. To elucidate proteolytic processing in astrocytomas and GBM tissues, we applied multiplexed Terminal Amine Isotopic Labeling of Substrates (TAILS) to globally assess cleavage events in disease progression. Comparative analyses identified > 10,000 protein N-termini in GBM and non-malignant tissues, and approximately 5300 non-redundant protein N-termini when comparing low grade astrocytomas with GBM tissues. Differential cleavage processes were identified for 27 mainly extracellular matrix proteins including tenascin, periostin, galectin-1, CD44, CD97. As proteases, we identified the calcium-dependent cysteine proteases (Calpains 1 and 2) as abundant in GBM. Their function is associated with enhanced chemoresistance to adjuvant therapy.

Conclusions: Our study provides an in-depth mass spectrometry based profiling of proteolytic events in the progression of early stages of astrocytomas to GBM and pinpoints Calpains as important mediators of chemoresistance of GBM.