Artikel
Targeting EGF-receptor in malignant gliomas with double stranded RNA poly(I:C) and polyethylene glycol-linear polyethylenimine as a carrier molecule
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Autoren
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V. Albrecht
- Tumorbiologisches Labor, Neurochirurgische Klinik und Poliklinik, Klinikum der Universität München
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J. Thorsteinsdottir
- Tumorbiologisches Labor, Neurochirurgische Klinik und Poliklinik, Klinikum der Universität München
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E. Wagner
- Pharmaceutical Biotechnology, Center for System-based Drug Research, Department of Pharmacy, Klinikum der Universität München
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J.C. Tonn
- Tumorbiologisches Labor, Neurochirurgische Klinik und Poliklinik, Klinikum der Universität München
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M. Ogris
- Pharmaceutical Biotechnology, Center for System-based Drug Research, Department of Pharmacy, Klinikum der Universität München
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C. Schichor
- Tumorbiologisches Labor, Neurochirurgische Klinik und Poliklinik, Klinikum der Universität München
| Veröffentlicht: | 28. April 2011 |
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Gliederung
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Objective: Glioblastoma multiforme (GBM) is characterized by an over-expression of the wtEGF receptor (EGFR) and its variant vIII (deltaEGFR), which is important for proliferation, invasion and angiogenesis of glial tumor cells. Targeted cellular delivery of proapoptotic, immune stimulatory double-stranded RNA polyinosinic:polycytidylic acid (poly(I:C)) via this receptor can be of therapeutical importance and was aim of this study.
Methods: For this study, tissue samples from glioblastomas (n=4) and non-neoplastic brain (n=2) have been stained immunohistochemically for EGFR/deltaEGFR expression. Additionally, different malignant glioma cell lines (U87, U251, U373, U138, U87wtEGFR, U87deltaEGFR) as well as cell subpopulations (endothelial cells (gbECs), mesenchymal stem like cells (gbMSCs), CD133-positive cells) isolated from GBM specimen in early passages (p<5) have been analyzed via immunocytochemistry and flow cytometry. Virus sized particles (polyplexes) were formed with RNA and a nucleic acid carrier conjugate based on linear polyethylenimine (LPEI) and an EGF receptor targeting ligand. Cells were then exposed to poly(I:C) polyplexes, the respective control poly(I) polyplexes or no polyplex for up to 48h. Inhibition of proliferation was measured with the sulforhodamine-B (SRB) proliferation assay.
Results: As expected, over-expression of EGFR was found in all glioma samples, compared to non-neoplastic brain. All tumor cell lines displayed over-expression of EGFR, except EGFR-negative U138-cells. The primary cultures, derived from GBM showed strong positivity for EGFR, whereas other subpopulations (gbMSCs, CD133-positive cells) only showed weak positivity. Endothelial cells displayed no EGFR-staining at all. Incubation of the cell lines and isolated cells with poly(I:C) polyplexes resulted in effective suppression of proliferation, depending on the EGF-receptor expression.
Conclusions: Tumor cell proliferation was effectively inhibited by treatment with the dsRNA-containing polyplexes targeting EGFR in malignant glial tumor cells. These findings render this agent a promising new candidate for a potential tumor cell receptor targeted therapy in glioblastoma.
