RESEARCH ARTICLE Is current therapy of malignant gliomas beneficial for patients? Proteomics evidence of shifts in glioma cells expression patterns under clinically relevant treatment conditions Daniela Trog 1 , Michael Fountoulakis 2 , Arno Friedlein 2 and Olga Golubnitschaja 1 1 Department of Radiology, Division of Molecular/Experimental Radiology, Friedrich-Wilhelms-University of Bonn, Bonn, Germany 2 F. Hoffmann La Roche, Center for Medical Genomics, Basel, Switzerland The most common human brain tumours – gliomas – have poor prognosis with and without treatment. The current therapy conditions act sub-lethally and cannot effectively suppress the proliferation of glioma cells. Here we show differential protein expression patterns in surviving human malignant U87-MG glioma cells under clinically relevant chemo/radiotherapy. In paral- lel experiments, the cells underwent either irradiation (2 Gy, 200 KV X-ray) or chemotreatment with 30 mg/mL of temozolomide in the cultivation medium or combined chemo/radiation treat- ment. The cell cultures were treated during 5 days from day 4 until day 9 of growth. Modulated expression patterns of vimentin and RhoA GTPase indicate a potentially increasing grade of malignancy in treated cell fractions correlating well with extremely aggressive tumour pheno- types observed clinically at recidivation of treated malignant gliomas. Received: August 5, 2005 Revised: December 13, 2005 Accepted: December 28, 2005 Keywords: Human malignant gliomas / Pro-invasive activity / Protein expression patterns / Therapy conditions 2924 Proteomics 2006, 6, 2924–2930 1 Introduction Malignant gliomas are the most common primary brain tumours in adults [1]. Due to its invasive character, surgery is unable to remove all tumour tissue and ancillary therapies such as 3-D conformal radiotherapy, stereotactic radiosurgery, and concurrent chemoradiotherapy are routinely used post- operatively. Despite this multidisciplinary approach, the prog- nosis of gliomas remains poor with a median survival in the range of 1 year due to local tumour recurrence [2]. Micro- vascular proliferation with multilayered endothelial cells and pericytes is the hallmark histopathological feature of gliomas, which contrasts with little or no microvascular proliferation in lower grade astrocytomas and oligodendromas, respectively. Apparently, gliomas acquire the capacity to induce neovascu- larisation in the process of progression to higher malignancy [3]. Activation of glioma-specific extracellular matrix compo- nents such as vimentin contributes to the mechanisms sup- porting the pro-invasive and pro-angiogenic tumour activity, and is another key determinant of vascular tissue and tumour cell proliferation in malignant tumours [4, 5]. Recent studies have attempted to elucidate the molecular mechanisms that explain the clinical observation of pro- gressive malignancy of gliomas under radiotherapy and chemotherapy. Surprisingly, radiation doses typically used in postoperative radiotherapy (2 Gy) increase the motility of surviving glioma cells [2, 6], and the fraction of motile cells by 20% in surviving glioma cells in vitro [6]. This may imply that current radiotherapy regimen may have counterintuitive effects. To model chemotherapy, we used the alkylating agent Correspondence: Professor Olga Golubnitschaja, Department of Radiology, Division of Molecular/Experimental Radiology, Uni- versity of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany E-mail: olga.golubnitschaja@ukb.uni-bonn.de Fax: 149-228-287-4457 DOI 10.1002/pmic.200500587  2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.proteomics-journal.com