gms | German Medical Science

Objective: Despite recent advances in diagnosis and treatment, high grade gliomas pose one of the major challenges in cancer research. Recently, evidence has mounted suggesting that the clinical properties of gliomas are largely determined by a small subpopulation of cancer cells that can continuously self-renew and regenerate the tumour and therefore might have escaped standard therapeutic strategies so far. In the present study we sought to establish primary cultures of putative glioblastoma stem cells and to study their properties in a preclinical model.

Methods: Putative tumour stem cells were isolated from human glioblastoma tissues by enzymatic digestion and grown as spheres in stem cell-optimized culture media. Tumour cells were immunohistochemically characterized for the expression of different markers including the stem cell markers nestin and CD133. DNA was isolated from single spheres and subjected to matrix-CGH analysis. To test their tumorigenic potential cells were implanted stereotactically in NOD/SCID mice.

Results: Primary cultures of putative stem cells derived from human glioblastomas formed spheres and could be kept in continuous culture. Spheres were analyzed for surface marker expression and found to be positive for nestin and CD133. Matrix-CGH revealed aberrations frequently found in glioblastoma, such as PDGFRA amplification and loss of 10q, demonstrating that the spheres were derived from tumour cells. Tumorigenity of our primary cultures was demonstrated by xenograft experiments in NOD-SCID mice, where tumours presented with a highly invasive phenotype.

Conclusions: These data not only support the present tumour stem cell concept but also provide a suitable tool to develop new strategies for the treatment of high grade gliomas. The thorough characterization of tumor stem cells will greatly improve our understanding of tumor pathomechanisms and provide keys for major improvements in cancer therapy.