INVITRO PLASMINOGEN ACTIVATOR ACTIVITY IN HUMAN-BRAIN TUMORS

Abstract

Cell cultures were prepared from 9 human brain tumors. Fibrin plate assays showed plasminogen-dependent fibrinolytic activity in lysates and material released by these neoplastic cells but not in those from normal adult human white matter. Antibodies against human urokinase caused catalytic inhibition of urokinase and plasminogen activator from WI-38 embryo lung cells, SV 40-transformed WI-38 cells, prostatic cells and ovarian carcinoma cells. The antiurokinase immunoglobulin G did not inhibit plasminogen activator activity of any of the brain tumor preparations. These studies indicate that plasminogen activator produced by human brain tumor cells is antigenically different from the plasminogen activator of other human normal and neoplastic cells.