INHIBITION OF COLLAGENOLYTIC ACTIVITY RELATES TO QUANTITATIVE REDUCTION OF INVASION IN-VITRO IN A C-HA-RAS TRANSFECTED GLIAL-CELL LINE

The function of proteases in brain tumor invasion is currently not wel l established. For tumors of epithelial and fibromatous origin collage nase production can enhance the invasive capacity of cells to penetrat e basement membranes. We showed previously that a c-Ha-ras transformed glial cell line (CxT24neo3) invaded hamster brain tissue in vivo. The se cells were also capable of invading reconstituted basement membrane and embryonic chick hearts in vitro. Since the histopathology of CxT2 4neo3 tumors mimics that of glioblastoma multiforme in humans, CxT24ne o3 was used as the model in vitro for this type of brain tumor. Presen tly, we detected by zymogram analysis a gelatinase that was secreted b y CxT24neo3 and that had an apparent molecular mass of 62 kD. To verif y whether gelatinase affected invasion in vitro of these glial cells w e determined the efficacy of a substrate specific collagenase inhibito r on invasion in vitro. GM6001 is a synthetic polypeptide that specifi cally occupies the substrate binding sites of metalloprotease. Since t his drug did not show cytotoxicity, its specificity for metalloproteas e is a valuable tool to evaluate the physiological function of these e nzymes on invasion. We found that treatment of CxT24neo3 with GM6001 r educed the fraction of invading CxT24neo3 cells through reconstituted basement membrane. These data suggest that metalloprotease can stimula te brain tumor invasion.