Dirk Vordermark

Universitätsklinikum Halle (Saale), Halle-on-the-Saale, Saxony-Anhalt, Germany

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Publications (169)726.77 Total impact

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    ABSTRACT: Tumor hypoxia is a known risk factor for reduced response to radiotherapy. The evaluation of noninvasive methods for the detection of hypoxia is therefore of interest. Osteopontin (OPN) has been discussed as an endogenous hypoxia biomarker. It is overexpressed in many cancers and is involved in tumor progression and metastasis. To examine the influence of hypoxia and irradiation on osteopontin expression we used different cell lines (head and neck cancer (Cal27 and FaDu) and glioblastoma multiforme (U251 and U87)). Cells were treated with hypoxia for 24 h and were then irradiated with doses of 2 and 8 Gy. Osteopontin expression was analyzed on mRNA level by quantitative real-time RT-PCR (qPCR) and on protein level by western blot. Cell culture supernatants were evaluated for secreted OPN by ELISA. Hypoxia caused an increase in osteopontin protein expression in all cell lines. In Cal27 a corresponding increase in OPN mRNA expression was observed. In contrast the other cell lines showed a reduced mRNA expression under hypoxic conditions. After irradiation OPN mRNA expression raised slightly in FaDu and U87 cells while it was reduced in U251 and stable in Cal27 cells under normoxia. The combined treatment (hypoxia and irradiation) led to a slight increase of OPN mRNA after 2 Gy in U251 (24 h) and in U87 (24 and 48 h) cell lines falling back to base line after 8 Gy. This effect was not seen in Cal27 or in FaDu cells. Secreted OPN was detected only in the two glioblastoma cell lines with reduced protein levels under hypoxic conditions. Again the combined treatment resulted in a minor increase in OPN secretion 48 hours after irradiation with 8 Gy. Osteopontin expression is strongly modulated by hypoxia and only to a minor extent by irradiation. Intracellular OPN homeostasis seems to vary considerably between cell lines. This may explain the partly conflicting results concerning response prediction and prognosis in the clinical setting.
    Radiation Oncology 12/2015; 10(1):167. DOI:10.1186/s13014-015-0473-x · 2.55 Impact Factor
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    ABSTRACT: Betulinic acid (BA), a natural compound of birch bark, is cytotoxic for many tumors. Recently, a betulinyl sulfamate was described that inhibits carbonic anhydrases (CA), such as CAIX, an attractive target for tumor-selective therapy strategies in hypoxic cancer cells. Data on combined CAIX inhibition with radiotherapy are rare. In the human breast cancer cell lines MDA-MB231 and MCF7, the effects of BA and betulinyl sulfamates on cellular and radiobiological behavior under normoxia and hypoxia were evaluated. The two most effective betulinyl sulfamates CAI 1 and CAI 3 demonstrated a 1.8-2.8-fold higher cytotoxicity than BA under normoxia in breast cancer cells, with IC50 values between 11.1 and 18.1 µM. BA exhibits its strongest cytotoxicity with IC50 values of 8.2 and 16.4 µM under hypoxia. All three substances show a dose-dependent increase in apoptosis, inhibition of migration, and inhibition of hypoxia-induced gene expression. In combination with irradiation, betulinyl sulfamates act as radiosensitizers, with DMF10 values of 1.47 (CAI 1) and 1.75 (CAI 3) under hypoxia in MDA-MB231 cells. BA showed additive effects in combination with irradiation. Taken together; our results suggest that BA and betulinyl sulfamates seem to be attractive substances to combine with radiotherapy; particularly for hypoxic breast cancer.
    International Journal of Molecular Sciences 11/2015; 16(11):26249-26262. DOI:10.3390/ijms161125953 · 2.86 Impact Factor
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    ABSTRACT: Heat-shock protein 70 (Hsp70) is frequently found on the plasma membrane of a large number of malignant tumors including non-small cell lung cancer (NSCLC) and gets released into the blood circulation in lipid vesicles. On the one hand, a membrane (m)Hsp70-positive phenotype correlates with a high aggressiveness of the tumor; on the other hand, mHsp70 serves as a target for natural killer (NK) cells that had been pre-stimulated with Hsp70-peptide TKD plus low-dose interleukin-2 (TKD/IL-2). Following activation, NK cells show an up-regulated expression of activatory C-type lectin receptors, such as CD94/NKG2C, NKG2D, and natural cytotoxicity receptors (NCRs; NKp44, NKp46, and NKp30) and thereby gain the capacity to kill mHsp70-positive tumor cells. With respect to these results, the efficacy of ex vivo TKD/IL-2 stimulated, autologous NK cells is currently tested in a proof-of-concept phase II clinical trial in patients with squamous cell NSCLC after radiochemotherapy (RCT) at the TUM. Inclusion criteria are histological proven, non-resectable NSCLC in stage IIIA/IIIB, clinical responses to RCT and a mHsp70-positive tumor phenotype. The mHsp70 status is determined in the serum of patients using the lipHsp70 ELISA test, which enables the quantification of liposomal and free Hsp70. Squamous cell and adeno NSCLC patients had significantly higher serum Hsp70 levels than healthy controls. A significant correlation of serum Hsp70 levels with the gross tumor volume was shown for adeno and squamous cell NSCLC. However, significantly elevated ratios of activated CD69(+)/CD94(+) NK cells that are associated with low serum Hsp70 levels were observed only in patients with squamous cell lung cancer. These data might provide a first hint that squamous cell NSCLC is more immunogenic than adeno NSCLC.
    Frontiers in Immunology 11/2015; 6. DOI:10.3389/fimmu.2015.00556
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    ABSTRACT: Nodular lymphocyte-predominant Hodgkin lymphoma (nLPHL) is a very rare disease in childhood and adolescence. In Germany, about 15 newly diagnosed patients present with this disease annually; this number comprises less than 10% of all pediatric Hodgkin lymphoma cases. Since the EuroNet-PHL-LP1 trial for early stage nLPHL patients stopped recruiting in Germany in October 2014, the GPOH-HD writing committee reviewed the literature and decided to deliver treatment recommendations for childhood and adolescent nLPHL patients. These guidelines shall be applicable to young nLPHL patients in European countries that will no longer be able to participate in nLPHL trials for young patients. Therefore, the EuroNet-PHL-nLPHL-registry will be installed to provide quality assured central review of staging and response assessment for registered patients by the Central Review Board of EuroNet-PHL in Halle/Leipzig, Germany.
    Klinische Pädiatrie 09/2015; 227(6-07). DOI:10.1055/s-0035-1559664 · 1.06 Impact Factor
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    ABSTRACT: In malignant glioma the presence of the IDH1 mutation (IDH1(R132H)) is associated with better clinical outcome. However, it is unclear whether IDH1 mutation is associated with a less aggressive phenotype or directly linked to increased sensitivity to radiotherapy. We determined the influence of IDH1(R132H) mutant protein on proliferation and growth in 3D culture, migration, cell survival and radiosensitivity in vitro under normoxia (21% O2) and hypoxia (<1% O2) in a panel of human malignant glioma cell lines (U-251MG, U-343MG, LN-229) with stable overexpression of wild-type (IDH1(wt)) and mutated IDH1 (IDH1(R132H)). Overexpression of IDH1(R132H) in glioma cells resulted in slightly decreased cell proliferation, considerably reduced cell migration and caused differences in growth properties in 3D spheroid cultures. Furthermore, IDH1(R132H)-positive cells consistently demonstrated an increased radiosensitivity in human malignant glioma cells U-251MG (DMF10: 1.52, p<0.01 and 1.42, p<0.01), U-343MG (DMF10: 1.78, p<0.01 and 1.75, p<0.01) and LN-229 (DMF10: 1.41, p<0.05 and 1.68, p<0.01) under normoxia and hypoxia, respectively. Our data indicate that IDH1(R132H) mutation causes both a less aggressive biological behavior and direct radiosensitization of human malignant glioma cells. Targeting IDH1 appears to be an attractive approach in combination with radiotherapy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    Radiotherapy and Oncology 08/2015; 116(3). DOI:10.1016/j.radonc.2015.08.007 · 4.36 Impact Factor
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    ABSTRACT: Background/purpose To evaluate whether radiation damage to dental hard tissues depends on patient-related factors in addition to irradiation dose on the spared parotid gland. Materials and methods Seventy curatively irradiated patients with head and neck cancer underwent dental treatment prior to, during, and after radiotherapy. During a follow-up period of 24 months, damages to dental hard tissues were classified. Mean doses (Dmean) during spared parotid gland radiotherapy, patients' oral hygiene practice, and socioeconomic status were determined. Results No carious lesions were observed in 30 patients (Group A), while sporadic and general carious lesions were noticed in 18 patients (Group B) and 22 patients (Group C), respectively. The Dmean of Group A (21.2 ± 11.00 Gy) was significantly lower than that of Group C (33.9 ± 9.9 Gy; P < 0.001). Patients with an intermediate level of schooling qualification showed a higher risk for radiation caries than patients with higher education entrance qualification (P = 0.018). Conclusion Radiation damage to dental hard tissues correlates with increased mean irradiation doses and a lower educational level. © 2015, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.
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    U. Wedding · D. Vordermark · C.-T. Germer · K. Höffken ·

    Der Onkologe 06/2015; 21(6):466-468. DOI:10.1007/s00761-014-2823-y · 0.14 Impact Factor
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    ABSTRACT: The roles of hypoxia-induced and stem cell-associated genes in the development of malignancy and tumour progression are well known. However, there are a limited number of studies analysing the impact of mRNA expression levels of hypoxia-induced and stem cell-associated genes in the tissues of brain tumours and glioblastoma patients. In this study, tumour tissues from patients with glioblastoma multiforme and tumour adjacent tissues were analysed. We investigated mRNA expression levels of hypoxia-inducible factor-1α (HIF-1α), hypoxia-inducible factor-2α (HIF-2α), carbonic anhydrase 9 (CA9), vascular endothelial growth factor (VEGF), glucose transporter-1 (GLUT-1) and osteopontin (OPN), and stem cell-associated genes survivin, epidermal growth factor receptor (EGFR), human telomerase reverse transcriptase (hTERT), Nanog and octamer binding transcription factor 4 (OCT4) using quantitative real-time polymerase chain reaction (qRT-PCR). Our data revealed higher mRNA expression levels of hypoxia-induced and stem cell‑associated genes in tumour tissue than levels in the tumour adjacent tissues in patients with glioblastoma multiforme. A strong positive correlation between the mRNA expression levels of HIF-2α, CA9, VEGF, GLUT-1 and OPN suggests a specific hypoxia-associated profile of mRNA expression in glioblastoma multiforme. Additionally, the results indicate the role of stem-cell-related genes in tumour hypoxia. Kaplan‑Maier analysis revealed that high mRNA expression levels of hypoxia-induced markers showed a trend towards shorter overall survival in glioblastoma patients (P=0.061). Our data suggest that mRNA expression levels of hypoxia‑induced genes are important tumour markers in patients with glioblastoma multiforme.
    Oncology Reports 06/2015; 33(6):3155-3161. DOI:10.3892/or.2015.3932 · 2.30 Impact Factor
  • U. Wedding · D. Vordermark ·
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    ABSTRACT: Hintergrund Das Ziel eines Erhalts der Lebensqualität gewinnt für alte Menschen mit Krebserkrankungen gegenüber der Lebenslänge mit zunehmendem Alter an Bedeutung. Ziel Es soll ein aktueller Überblick zum Thema Lebensqualität bei alten Menschen mit Krebserkrankungen vermittelt werden. Material und Methode Es erfolgte eine selektive Literaturrecherche, und es werden Beispiele aus eigenen Daten dargestellt. Ergebnisse In der Allgemeinbevölkerung zeigt sich in der Gruppe der sehr alten Menschen (80 Jahre und älter) eine schlechtere Lebensqualität als bei jüngeren Menschen. Liegen Einschränkungen in Bereichen des geriatrischen Assessments vor, so sind diese Einschränkungen auch meist mit einer schlechteren Lebensqualität der älteren Krebspatienten assoziiert. Es stehen strukturierte Instrumente zur Erfassung der Lebensqualität zur Verfügung, z. B. der EORTC-QLQ-ELD14-Fragebogen. Besondere Bedeutung für die Lebensqualität älterer Menschen hat die Fähigkeit zur Selbstversorgung. Nur wenige Studien sind jedoch bisher mit dem Endpunkt Erhalt oder Wiederherstellung der Selbstversorgungsfähigkeit durchgeführt worden. Schlussfolgerung Die Lebensqualität sollte sowohl in klinischen Studien für alte Patienten mit Krebserkrankungen als auch in der Routineversorgung ein wesentlicher Endpunkt sein.
    Der Onkologe 05/2015; 21(6). DOI:10.1007/s00761-014-2827-7 · 0.14 Impact Factor
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    ABSTRACT: To assess, in a prospective, observational study, the safety and efficacy of the addition of the neurokinin-1-receptor antagonist (NK1-RA) aprepitant to concomitant radiochemotherapy, for the prophylaxis of radiation therapy-induced nausea and vomiting. This prospective observational study compared the antiemetic efficacy of an NK1-RA (aprepitant), a 5-hydroxytryptamine-RA, and dexamethasone (aprepitant regimen) versus a 5-hydroxytryptamine-RA and dexamethasone (control regimen) in patients receiving concomitant radiochemotherapy with cisplatin at the Department of Radiation Oncology, University Hospital Halle (Saale), Germany. The primary endpoint was complete response in the overall phase, defined as no vomiting and no use of rescue therapy in this period. Fifty-nine patients treated with concomitant radiochemotherapy with cisplatin were included in this study. Thirty-one patients received the aprepitant regimen and 29 the control regimen. The overall complete response rates for cycles 1 and 2 were 75.9% and 64.5% for the aprepitant group and 60.7% and 54.2% for the control group, respectively. Although a 15.2% absolute difference was reached in cycle 1, a statistical significance was not detected (P=.22). Furthermore maximum nausea was 1.58 ± 1.91 in the control group and 0.73 ± 1.79 in the aprepitant group (P=.084); for the head-and-neck subset, 2.23 ± 2.13 in the control group and 0.64 ± 1.77 in the aprepitant group, respectively (P=.03). This is the first study of an NK1-RA-containing antiemetic prophylaxis regimen in patients receiving concomitant radiochemotherapy. Although the primary endpoint was not obtained, the absolute difference of 10% in efficacy was reached, which is defined as clinically meaningful for patients by international guidelines groups. Randomized phase 3 studies are necessary to further define the potential role of an NK1-RA in this setting. Copyright © 2015 Elsevier Inc. All rights reserved.
    International journal of radiation oncology, biology, physics 04/2015; 92(5). DOI:10.1016/j.ijrobp.2015.04.037 · 4.26 Impact Factor
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    ABSTRACT: The brain is one of the most frequent locations of metastasis in malignant melanoma. We aimed to identify prognostic factors for overall survival (OS) and local tumor control (LC) in patients with malignant melanoma metastasized to the brain treated by multimodal therapy. All patients diagnosed with malignant melanoma brain metastases between 1992 and 2011 at a single center were registered (n=100, 65% male, 35% female). OS and LC of individual brain metastases were retrospectively analyzed. Subgroup analyses was performed in patients with multiple brain metastasis (n=35) and LC per lesion (n=72) was evaluated in 37 patients. Median age was 57 (27-81) years. Fifty-three percent of patients had 1-2 brain metastases, 47% had >2 and 71% presented with additional extracranial metastases. Primary treatment included systemic therapy alone (temozolomide/fotemustine, 14%), local therapy (surgery and/or stereotactic radiotherapy, 25%), whole-brain radiotherapy (WBRT, 10%), combined WBRT and systemic therapy (18%), local therapy plus WBRT (5%) and combination of local and systemic therapy (8%). Three percent received a tri-modal therapy (WBRT, local and systemic therapy) and 17% refused treatment. Median follow-up in surviving patients was 32 (4-222) months, median OS in all patients 3.9 months (1-year survival 21.4%). Local therapy (p<0.001), systemic therapy (p=0.002), number of brain metastases and primary therapy including a local therapy (p<0.001) were significantly associated with OS. In the subgroup with multiple brain metastases (n=35), a trend (p=0.058) for improved OS after initial treatment with WBRT plus systemic therapy was noted (median OS 3.8 months) and use of these two modalities over the course of the disease was significantly associated with OS (p=0.007). The best LC per single lesion (n=37) could be achieved by combination of local with systemic therapy (p=0.011). Number of brain metastases, extracranial metastases and use of local therapy are independent prognostic factors in melanoma metastatic to the brain. LC and OS can be improved by combining local with systemic treatment. In patients with multiple brain metastases, WBRT plus systemic therapy provides superior OS.
    International Journal of Oncology 04/2015; 46(6). DOI:10.3892/ijo.2015.2970 · 3.03 Impact Factor
  • C Ostheimer · F Meyer · C Kornhuber · T Reese · D Vordermark ·
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    ABSTRACT: Radiooncological therapies are an integral part of the multimodal oncological treatment concepts in general and abdominal surgery. These include therapeutic approaches with a curative intention such as the neoadjuvant (pre-operative) radiotherapy of locoregionally advanced and/or N+ oesophageal and rectal cancer, definitive combined chemoradiotherapy of locally advanced, unresectable oesophageal cancer or oesophageal tumour lesions of the upper third, definitive radiotherapy of anal cancer (sphincter sparing) and pre- or post-operative radiotherapy of soft tissue sarcoma on the one hand. A yT0 stage achieved as characteristic of a curative effect by radiation in oesophageal and rectal cancer (omitting subsequent surgical intervention, naturally under clinical and imaging-based controls within short-term follow-up intervals) can be considered as a very interesting set-up with regard to its reasonable integration in daily clinical practice, which needs to be further and critically discussed. By integrating radiotherapy in interdisciplinary therapy concepts, improved tumour control and survival rates with clinically acceptable toxicity can be achieved. On the other hand, non-invasive, locally ablative radiooncological therapies such as extracranial stereotactic body radiotherapy constitute an effective and feasible treatment method for liver metastases in oligometastatic colorectal cancer or other tumour entities according to the decisions by the institutional tumour board, offering high local tumour control rates which can be part of multistep, multimodal procedures with curative intention. This review aims at providing an overview for the general and abdominal surgeon, outlining relevant radiooncological treatment aspects in the multimodal cancer therapy with a focus on the treatment of rectal, oesophageal and anal cancer as well as soft tissue sarcoma and hepatic metastases in oligometastatic colorectal cancer. Georg Thieme Verlag KG Stuttgart · New York.
    Zentralblatt fur Chirurgie, Supplement 02/2015; 140(1):83-93. DOI:10.1055/s-0034-1383338
  • C. Ostheimer · M. Bache · A. Güttler · D. Vordermark ·

    Radiotherapy and Oncology 12/2014; 111:S297. DOI:10.1016/S0167-8140(15)31939-3 · 4.36 Impact Factor
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    ABSTRACT: In very elderly cancer patients, health-related quality of life (HRQOL) is a particularly important issue but has rarely been studied due to a lack of specific instruments and of reference data. We performed a prospective analysis of HRQOL in patients ≥80 years undergoing radiotherapy with the newly validated elderly-specific HRQOL module EORTC QLQ-ELD14. We prospectively assessed HRQOL in n = 50 radiotherapy patients ≥80 years (32 % lung, 20 % gastrointestinal, 8 % each of breast, head and neck, gynecologic cancer) at the start (t1), end (t2), and 6 months after (t3) radiotherapy, using EORTC QLQ-C30 and EORTC QLQ-ELD14. Overall survival was determined in the whole cohort and subgroups. Median overall survival from the start of radiotherapy was 15 months; 1-year and 2-year overall survival rates were 57.1 and 31.0 %, respectively. Eastern Cooperative Oncology Group (ECOG) performance status <2, Charlson comorbidity index ≤6, curative treatment intention, local tumor stage Union Internationale Contre le Cancer (UICC I, II), and total dose >45 Gy were associated with prolonged survival. No significant changes in any HRQOL domain were observed during the course of treatment (t1 to t2). Six months after radiotherapy (t3), a significant and clinically relevant deterioration of HRQOL was seen in EORTC QLQ-C30 for physical function and role function and in EORTC QLQ-ELD14 for future worries, burden of illness, and family support. In radiotherapy patients ≥80 years, HRQOL was maintained until the end of radiotherapy but deteriorated in general and elderly-specific areas thereafter, suggesting a need to develop specific supportive interventions for this age group.
    Supportive Care Cancer 12/2014; 111(7). DOI:10.1007/s00520-014-2546-z · 2.36 Impact Factor
  • D Körholz · C Mauz-Körholz · D Vordermark · R Kluge · K Dieckmann ·

    Klinische Pädiatrie 11/2014; 226(6-7):307-8. DOI:10.1055/s-0034-1389928 · 1.06 Impact Factor
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    ABSTRACT: Circulating baseline levels of the plasma-protein osteopontin (OPN) have been suggested as a prognostic indicator in chemotherapy and surgery for lung cancer. However, the role of this hypoxia-related protein in radiotherapy of lung cancer is unclear. We previously demonstrated the prognostic effect of baseline OPN plasma levels which was increased by co-detection with other hypoxia-related proteins in the radical radiotherapy of non-small-cell lung cancer (NSCLC). This prospective clinical study investigated whether serial OPN measurements during and after curative-intent radiotherapy for NSCLC provide additional or superior prognostic information. Sixty-nine patients with inoperable NSCLC were prospectively enrolled (55 M0, 14 M1). OPN plasma levels were measured before (t0), at the end (t1) and four weeks after radiotherapy (t2) by ELISA, compared between M0 and M1 patients and correlated with clinicopathological parameters. OPN levels were monitored over time and correlated with prognosis in M0-stage patients treated by radical 66-Gy radiotherapy +/- chemotherapy. Pre-treatment OPN levels were associated with T stage (p = .03), lung function (p = .002), weight loss (p = .01), tumor volume (p = .02) and hemoglobin concentration (p = 04). M1 patients had significantly elevated OPN levels at all time points (p < .001). Patients with increasing OPN levels after radiotherapy had inferior freedom from relapse (p = .008), overall survival (p = .004) and disease-free survival (p = .001) compared to patients with stable or decreasing OPN levels. The risk of relapse in patients with increasing or stable OPN levels after radiotherapy was increased by a factor of 2.9 (p = .01). Patients with increasing post-treatment OPN levels had a 3.1-fold increased risk of death (p = .003). In an exploratory multivariate model, post-treatment OPN level changes but not absolute baseline OPN levels remained an independent prognostic factor for overall survival (p = .002) with a 3.6-fold increased risk of death, as well as N stage (p = .006). Our results suggest that OPN level changes over time, particularly post-treatment, may yield additional prognostic information in curative-intent radiotherapy of NSCLC.
    BMC Cancer 11/2014; 14(1):858. DOI:10.1186/1471-2407-14-858 · 3.36 Impact Factor
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    ABSTRACT: Betulinic acid (BA), a pentacyclic triterpene, represents a new therapeutic substance that has potential benefits for treating glioblastoma. Recently, new strategies for producing BA derivatives with improved properties have evolved. However, few studies have examined the combination of BA or BA derivatives using radiotherapy. The effects of two BA derivatives, NVX-207 and B10, on cellular and radiobiological behavior were analyzed using glioblastoma cell lines (U251MG, U343MG and LN229). Based on IC50 values under normoxic conditions, we detected a 1.3-2.9-fold higher cytotoxicity of the BA derivatives B10 and NVX-207, respectively, compared to BA. Incubation using both BA derivatives led to decreased cell migration, cleavage of PARP and decreased protein expression levels of Survivin. Weak radiation sensitivity enhancement was observed in U251MG cells after treatment with both BA derivatives. The enhancement factors at an irradiation dose of 6 Gy after treatment with 5 µM NVX-207 and 5 µM B10 were 1.32 (p = 0.029) and 1.55 (p = 0.002), respectively. In contrast to BA, neither NVX-207 nor B10 had additional effects under hypoxic conditions. Our results suggest that the BA derivatives NVX-207 and B10 improve the effects of radiotherapy on human malignant glioma cells, particularly under normoxic conditions.
    International Journal of Molecular Sciences 11/2014; 15(11):19777-19790. DOI:10.3390/ijms151119777 · 2.86 Impact Factor
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    Dirk Vordermark ·

    Journal of Clinical Oncology 09/2014; 32(30). DOI:10.1200/JCO.2014.56.2215 · 18.43 Impact Factor
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    ABSTRACT: Background: The epidermal growth factor receptors, EGFR (HER1) and HER2, have proven prognostic relevance in a variety of human malignancies and both are functionally involved in the molecular pathogenesis of malignant gliomas. Material and methods: We selectively inhibited EGFR and HER2 in glioblastoma cell lines via EGFR- and HER2-specific siRNAs and through the binding of the therapeutic antibodies cetuximab and trastuzumab. The expression of EGFR and HER2 was verified by real-time PCR and western blot analyses. We examined the growth rate, cell cycle distribution, cell migration, clonogenic survival, and radiosensitivity of U251MG and LN-229 glioblastoma cell lines to determine the physiological and cell biological effects of EGFR and HER2 targeting. Results: EGFR and HER2 targeting using the therapeutic antibodies cetuximab and trastuzumab had no effect on cellular growth rate, cell cycle distribution, cell migration, clonogenic survival, and radiosensitivity in the cell lines U251 and LN-229. In contrast, siRNA knock-down of EGFR and HER2, reduced the growth rate by 40-65 %. The knock-down of EGFR did not change the cell migration rate in the cell lines U251 and LN-229. However, knock-down of HER2 reduced the cell migration rate by 50 %. Radiobiological analysis revealed that EGFR knock-down induced no radiosensitization in U251MG and LN-229 cells. However, the knock-down of HER2 induced radiosensitization in U251MG cells. Conclusion: The epidermal growth factor receptor HER2 is a promising anti-tumor target for the therapy of glioblastoma. HER2 targeting may represent a promising strategy to induce cell physiological and radiobiological anti-tumor effects in glioblastoma.
    Strahlentherapie und Onkologie 08/2014; 191(2). DOI:10.1007/s00066-014-0743-9 · 2.91 Impact Factor
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    ABSTRACT: Background Sialic acids (Sia) represent negative-charged terminal sugars on most glycoproteins and glycolipids on the cell surface of vertebrates. Aberrant expression of tumor associated sialylated carbohydrate epitopes significantly increases during onset of cancer. Since Sia contribute towards cell migration ( = metastasis) and to chemo- and radiation resistance. Modulation of cellular Sia concentration and composition poses a challenge especially for neuroblastoma therapy, due to the high heterogeneity and therapeutic resistance of these cells. Here we propose that Metabolic Sia Engineering (MSE) is an effective strategy to reduce neuroblastoma progression and metastasis. Methods Human neuroblastoma SH-SY5Y cells were treated with synthetic Sia precursors N-propanoyl mannosamine (ManNProp) or N-pentanoyl mannosamine (ManNPent). Total and Polysialic acids (PolySia) were investigated by high performance liquid chromatography. Cell surface polySia were examined by flow-cytometry. Sia precursors treated cells were examined for the migration, invasion and sensitivity towards anticancer drugs and radiation treatment. Results Treatment of SH-SY5Y cells with ManNProp or ManNPent (referred as MSE) reduced their cell surface sialylation significantly. We found complete absence of polysialylation after treatment of SH-SY5Y cells with ManNPent. Loss of polysialylation results in a reduction of migration and invasion ability of these cells. Furthermore, radiation of Sia-engineered cells completely abolished their migration. In addition, MSE increases the cytotoxicity of anti-cancer drugs, such as 5-fluorouracil or cisplatin. Conclusions Metabolic Sia Engineering (MSE) of neuroblastoma cells using modified Sia precursors reduces their sialylation, metastatic potential and increases their sensitivity towards radiation or chemotherapeutics. Therefore, MSE may serve as an effective method to treat neuroblastoma.
    PLoS ONE 08/2014; 9(8):e105403. DOI:10.1371/journal.pone.0105403 · 3.23 Impact Factor

Publication Stats

2k Citations
726.77 Total Impact Points


  • 2009-2015
    • Universitätsklinikum Halle (Saale)
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 2008-2015
    • Martin Luther University Halle-Wittenberg
      • Institute for Pathology
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 2014
    • Boston University
      • Department of Epidemiology
      Boston, Massachusetts, United States
  • 2013
    • OncoRay- Center for Radiation Research in Oncology
      Dresden, Saxony, Germany
  • 1999-2012
    • University of Wuerzburg
      • Department of Radiation Oncology
      Würzburg, Bavaria, Germany
  • 2011
    • Hannover Medical School
      • Clinic for Dermatology, Allergology and Venerology
      Hannover, Lower Saxony, Germany
  • 2005
    • University Hospital Regensburg
      Ratisbon, Bavaria, Germany
  • 2001-2003
    • Stanford Medicine
      • • Division of Radiation and Cancer Biology
      • • Department of Radiation Oncology
      Stanford, California, United States