Additional file 8: Invasion of GBM9/U251MG-NTN1(II)FH mixture spheroids in 3D Matrigel. Video (file format QuickTime, extension.mov) represents the invasion of spheroids consisting of GBM9 and U251MG-NTN1(II)FH cells. The spheroids were embedded into 3D Matrigel and monitored for 24 h. Images and video were captured similarly as in Additional file 6. Frames of various time points are presented in Fig. 6b.