Immunofluorescence staining of spheroids/adherent cells Spheroids/adherent cells were stained with human-specific mouse-anti-nestin antibodies (Millipore, Billerica, MA), goat-anti-SOX2 antibodies (R&D), mouse-anti-b2tubulinIII (Millipore) antibodies and mouse-anti-GFAP antibodies (Millipore). Primary antibodies were incubated overnight at 4uC. Alexa-Fluor647-goatanti-mouse und Alexa-Fluor647-donkey-anti-goat antibodies (Dianova, Hamburg, Germany) were used as secondary antibodies over night at 4uC (for spheroids) or for 2h at room temperature (for adherent cells). Spheroids were examined under a fluorescence microscope (Nikon, Tokyo, Japan) and adherent cells were analyzed by confocal scanning laser microscopy (Zeiss, Jena, Germany).