THE SELECTIVE ANTICANCER AGENT PB-100 INHIBITS INTERLEUKIN-6 INDUCED ENHANCEMENT OF GLIOBLASTOMA CELL-PROLIFERATION IN-VITRO

The multifunctional cytokine interleukin-6 behaves as a growth factor for various malignancies. It is produced in significant amounts by gli oblastoma cells. When exogenous IL-6 is added (pg/ml) to culture mediu m of human glioblastoma cells and normal (non malignant) astrocytes us ed as controls, it exerts a dose dependent and differential effect on these two cell lines. Enhancement of cell proliferation is twice as hi gh for glioblastoma cells as for astrocytes. In vitro, the novel antic ancer agent PB-100 (mu g/ml) dose dependently inhibits this stimulator y activity. In addition, increasing PB-100 concentrations finally indu ce death of the malignant cells, yet do not impede multiplication of n ormal astrocytes. PB-100 does not abolish IL-6 production by cells, bu t keeps its level down to physiological values. PB-100 should therefor e find its place in therapies requiring control of IL-6 production.