FIGURE 1.

Oct4 is essential for retention of stemness of glioma-initiating cells. A, TGS-01 and TGS-04 cells were dissociated into single cell populations, transfected with control (NC) or Oct4 siRNA duplex, and cultured for 7 days (1st). After the 7-day culture, spheres were dissociated into single cell populations and equal numbers of cells were cultured for another 7 days (2nd). Values are the number of glioma spheres formed (means ± S.E. of five fields). *, p < 0.001. Scale bars, 100 μm. B, knockdown of Oct4 expression by siRNA in TGS-01 and TGS-04 cells resulted in a decrease of self-renewal capacity in limiting dilution assay. C, immunostaining of TGS-01 cells. Spheres were disaggregated, seeded on poly-l-ornithine- and fibronectin-coated slide glasses, and cultured in serum-free medium with control (NC) or Oct4 siRNA duplex for 7 days. Quantification of Nestin-, Musashi-, Tuj1-, or glial fibrillary acidic protein (GFAP)-positive cells is shown in the right graphs. *, p < 0.01. Scale bars, 50 μm.