Regulation of Brain Tumor Dispersal by NKCC1 Through a Novel Role in Focal Adhesion Regulation
Figure 1
NKCC1 activity is necessary for GB cell invasion in vitro and its inhibition leads to formation of less invasive tumors in vivo.
Quantification of transwell invasion assays of primary-cultured GB cells exposed to increasing doses of the NKCC1 inhibitor bumetanide (A) or transduced with NKCC1 shRNA (B); exposed to 10 µM of the KCC inhibitor DIOA (C) or stably transduced with KCC4 shRNA (D). Insets show schematic representation of the experimental design in (A) and (D). (E–F) Orhtotopic in vivo tumors formed by NKCC1shRNA cells were significantly larger and less invasive than control cells. Inset shows NKCC1 knockdown by protein expression. (G) Representative images of DAPI-stained coronal sections of mouse brains, after the implantation of control shRNA (left panel) or NKCC1 shRNA (right panel) cells. (G′) Confocal images of human-specific Nestin positive cells migrating across the corpus callosum at the area in the dotted square in (G). These results suggest that NKCC1 expression is necessary for efficient GB cell migration in vivo. Scale bars, 500 µm in low magnification panels and 20 µm in high confocal images panels. Bars represent mean ± SEM. * p value<0.05; ** p<0.005.