Figure 3.

Cdc42 and Ect2 regulate TWEAK-induced glioma cell migration in vitro and Fn14-induced invasion ex vivo. A, T98G and U118 glioma cells were transfected with siRNA targeting either control nonmammalian luciferase (Ctrl) or 2 independent siRNA oligonucleotides targeting Cdc42 (Cdc42-1 and Cdc42-2). After 24 hours, cells were cultured in reduced serum medium (0.5% FBS) for 16 hours and were seeded onto 10-well glass slides precoated with 10 µg/mL human laminin. Cells were either left untreated or treated with TWEAK, and glioma cell migration was assessed over 24 hours. Data represent the average of 3 independent experiments (*, P < 0.01). B, T98G and U118 glioma cells were stably transduced with lentiviruses expressing GFP alone (V), the Fn14 wild-type (WT), or the cytoplasmic domain–truncated Fn14 receptor (tCT). In certain experiments, cells were either transfected with siRNA oligonucleotides against Cdc42, Ect2 or control luciferase (ctrl). Cells were implanted bilaterally onto the putamen of murine organotypic brain slices and observed at 48 hours. Depth of invasion was then calculated from z-axis images collected by confocal laser scanning microscopy. The mean value of the depth of invasion was obtained from 6 independent experiments (*, P < 0.01).