CD44 expression and MMP-2 secretion by mouse glioma cells: Effect of interferon and anti-CD44 antibody

We have previously reported that invasiveness of mouse glioma G-26, which e xpresses CD44 adhesion molecule, was inhibited in vitro following treatment with anti-CD44 antibody or mouse interferon alpha/beta (MuIFN alpha/beta. Here, we evaluated whether the expression of transmembrane CD44 adhesion mo lecule and/or secretion of extracellular matrix metalloproteinases (MMPs) w ere affected when glioma cell invasion was inhibited. Flow cytometric evalu ation of CD44 adhesion molecule expression in G-26 glioma using anti-CD44 a ntibody, confirmed that G-26 cells were CD44(+). Following 3-day treatment with MuIFN alpha/beta at 8x10(2) or 8x10(3) IU/ml of glioma cells, the expr ession of CD44 was not significantly affected as reflected by CD44(+) cell number and fluorescence intensity. The pretreatment of glioma cells for 1 d ay with anti-CD44 antibody resulted in a 30-60% decrease of CD44 expression . This coincided with significantly (p<0.05) lower cell activity as judged by MTT assay for mitochondrial activity The zymographic evaluation of MMP a ctivity in the G-26 glioma cell culture showed a high level of the active f orm of MMP-2 This level of MMP-2 was decreased following 3 day treatment of G-26 glioma cells with either 8x10(2) or 8x10(3) IU/ml of MuIFN<alpha>/bet a but only the latter concentration produced statistically significant 55% decrease. However; following a 1 day treatment of G-26 glioma cells with an ti-CD44 antibody, the level of active MMP-2 form was not significantly affe cted These findings indicate that while the inhibitory effect of IFN on gli oma invasion was accompanied by a decreased level of the active form of MMP -2 released extracellularly, the expression of the transmembrane CD44 adhes ion molecule was not affected. Conversely, anti-CD44 antibody pretreatment of G-26 glioma, which led to the inhibition of glioma invasion, resulted in decreased CD44 expression and lower cell activity but had no effect on the MMP-2.