Valproic acid inhibits proliferation and changes expression of CD44 and CD56 of malignant glioma cells in vitro.

Abstract

Recently we were able to show that valproic acid (VPA) induces growth-arrest and differentiation of human neuroblastoma cells. Hence we investigated in vitro the antitumoral effects of VPA on malignant gliomas by determining cell proliferation and expression of CD56 and CD44 of human T98G, A172, 85HG66, 86HG39 and rat C6 cell lines. VPA at concentrations ranging from 0.1 to 1 mM strongly inhibited proliferation of A172, 86HG39, 85HG66 and C6 cells in a dose-dependent manner, whereas T98G cell growth remained unchanged. All human glioma cells were highly positive for CD44, whereas CD56 was differently expressed. After 7 days of incubation with 1mM VPA CD56 expression was markedly increased in T98G, A172 and 85HG66 cells, whereas CD44 expression was decreased in all human cell lines. These data suggest that VPA has antitumoral effects on malignant glioma cells. Therefore we consider VPA as a potent therapeutic agent for treatment of these tumors.