Description

Modifications of culture conditions determine tumorigenicity in early passage patient-derived human glioblastoma cell lines

Carl Friedrich Classen, Doreen William, Madlin Walther

University Children’s Hospital Rostock, Ernst Heydemann-Str. 8, D-18057 Rostock, Germany

In contrast to most other malignant diseases, particularly in children, glioblastoma multiforma still is a lethal diagnosis for most of the patients. Operation and radiotherapy are very effective to reduce the tumor burden, however, a strong adjuvant treatment is lacking. To target glioblastoma cells more effectively, it is important to analyze tumor cell behavior in appropriate models. We studied cell lines established from individual glioblastoma patients focusing on tumorigenicity and gene expression profiles upon different culture conditions, including classical cell culture (with 10% fetal calf serum) and cancer stem cell culture (serum free, supplemented with growth factors), both as adherent or spheroid culture, and we analysed the effect of continuous treatment with the cytostatic drug temozolomide (50µM). First results showed that, in consistency with the cancer stem cell hypothesis, cells cultivated upon stem cell culture conditions displayed an increased tumorigenicity in vitro, as compared to their respective serum culture counterparts. Cells cultivated as spheroids achieved a more stem-like phenotype than adherent cells; and similar effects were observed after treatment with temozolomide (50µM). Doxycycline is a polycyclic antibiotic, inhibiting protein biosynthesis by binding to the small subunit (30S) of bacterial ribosomes. Since it acts similarly on the 28S subunit of mitochondrial ribosomes, which could be a critical part in the metabolism of stem-like cells, we studied it in our temozolomide-induced tumorigenicity model. Interestingly, doxycycline reversed the effects of temozolomide. In summary, we found that by numerous modifications of growth conditions, the stem-like phenotype and tumorigenicity of glioblastoma cells may be influenced, thus opening new options for a targeted approach in glioblastoma therapy.