The effect of interferon and anti-CD44 antibody on mouse glioma invasiveness in vitro.

In this study the effect of interferon and anti-CD44 antibody on the invasiveness of mouse glioma G-26 cells was evaluated. We confirmed the glial nature of G-26 glioma cells (G-26) in vitro and in vivo using immunohistochemistry: G-26 stained strongly for S-100 and stained weakly for glial fibrillary acidic protein (GFAP). Immunohistochemical evaluation for CD44 adhesion molecule showed that G-26 was positive both in vitro and in vivo. Weakly positive punctate staining for CD44 was seen in the cytoplasm of all viable glioma cells and focally strong staining was observed in a membranous pattern in the invading glioma cells. Evaluation of untreated G-26 cells using an in vitro invasion assay showed that they were able to digest a Matrigel matrix and to invade through an 8 microns microporous membrane. Treatment of the G-26 glioma cells for 3-4 days with mouse interferon alpha/beta at 8 x 10(2) or 8 x 10(3) mu/ml resulted in a significant decrease of invasiveness: 68.8% (p < 0.05) and 32.8% (p < 0.001) of cells, respectively, remained invasive when compared to control. Treatment of G-26 with antibody to the CD44 adhesion molecule significantly decreased invasiveness with 39.4% (p < 0.001) of cells remaining invasive when compared to control. We feel that both of these approaches, each of which produced significant inhibition of G-26 glioma cell invasion should be further evaluated for their usefulness in antiglioma therapy.