Autophagy Involvement in Olanzapine-Mediated Cytotoxic Effects in Human Glioma Cells

Abstract

The aim of this study was to investigate the effects of olanzapine on growth inhibition as well as autophagy inglioma cells in vitro and in vivo. The proliferation of both LN229 and T98 glioma cells, measured by MTT assay,was suppressed in a concentration-dependent and time-dependent manner. Moreover, apoptosis of both cellswas significantly increased with the treatment of olanzapine as evidenced by increased Bcl-2 expression, Hoechst33258 staining and annexinV-FITC/PI staining. Olanzapine treatment also enhanced activation of autophagy withincreased expression of LC3-II, expression of protein p62, a substrate of autophagy, being decreased. The growthinhibition by olanzapine in both glioma cell lines could be blocked by co-treatment with 3-MA, an autophagyinhibitor. Furthermore, olanzapine effectively blocked the growth of subcutaneous xenografts of LN229 gliomacells in vivo. The increased level of protein LC3-II and decreased level of p62 followed by a decreased level ofBcl-2, suggesting that autophagy may contribute to apoptosis. In addition, reduced proliferation of glioma cellswas shown by a decrease of Ki-67 staining and increased caspase-3 staining indicative of apoptosis in mousexenografts. These results indicated that olanzapine inhibited the growth of glioma cells accompanied by inductionof autophagy and apoptosis both in vitro and in vivo. Olanzapine-induced autophagy plays a tumor-suppressingrole in glioma cells.