RhoG is necessary for glioblastoma cell invasion. A) Brain slice invasion assay. GFP-expressing SNB19 and U87 glioblastoma cells were transfected with siRNAs (10 nM) directed against luciferase (control) or RhoG (two different oligos). The brain slice invasion assay was performed as described in Materials and Methods. Shown are the mean (+/−SEM) of three independent experiments, each performed in triplicate. Differences between RhoG knockdown and control are significant (p < 0.001, two-tailed t test). B) Western blot demonstrating depletion of RhoG in SNB19 cells. C and D) Depletion of RhoG has only a marginal inhibitory effect on cell proliferation. SNB19 cells were transfected with siRNAs (10 nM) directed against luciferase (control, solid squares) or RhoG (RhoG-2, empty squares; RhoG-3, empty triangles). Cell proliferation was quantified using the Sulphorhodamine B assay as described in Materials and Methods, either in the presence of 10% FBS (C) or in the absence of serum (D). Results shown represent the mean +/− SEM for respectively 6 independent experiments (C) and 4 independent experiments (D).