Figure 1. The GBM neurosphere cultures express neuronal and astrocytic differentiation markers upon in vitro induced differentiation.

Morphology of two representative NS cell lines, GN1C and G63, is shown at their basal state of NS (A, left panels) and after induction of their differentiation for 4 (4d) (A, central panels) and 14 days (14d) (A, right panels). All images were captured using an inverted optical microscope Leica DMIRB with 20X magnification. Expression of progenitor (Nestin), astrocytic (GFAP) and neuronal (TUJ1) markers was measured by q-RT-PCR in the NS cell lines G59, G97C, G63, G52 and GN1C (B) at the basal NS state and upon 4 (4d) or 14 (14d) days of induction of differentiation. Data were normalized to GAPDH expression as 2^-ΔCt. * indicates statistical p value <0.05 using unpaired t-test with the Holm-Bonferroni correction for multiple comparisons. Protein expression of Nestin, GFAP and TUJ1, as well as the presence of the oligodendrocytic sulfatide marker O4 (C), were analyzed by immunofluorescence in the GN1C cell line at the NS state (NS) and after 14 days (14d) of differentiation using secondary antibodies conjugated to FITC (green) or Texas Red (red) counterstained with DAPI (blue). Images were acquired at 20X magnification with a 739CCD camera coupled to an Axio Imager Z1 microscope (Carl Zeiss Inc.) using the Isis Imaging System software.