Withaferin A exerts anti-tumor effects in glioblastoma cells by arresting cell cycle at G_2/M phase

Glioblastoma(GBM) is the most common,malignant,and lethal primary brain tumor in adults.Up to now,there is no effective drug for GBM.Withaferin A(WFA) is mainly derived from Indian Winter cherry.It has been traditionally used in ayurvedic medicine.WFA has wide range of pharmaco.logical activities including cardioprotective,anti-inflammatory,immuno-modulatory properties.Recently,WFA was reported to inhibit the growth of many cancer cells;however,the precise molecular mecha.nisms of its anti-cancer activities in GBM remain unclear.Here,we found that treatment of WFA in U251 and U87-MG glioma cells inhibited the cell proliferation,released the cellular LDH,decreased the DNA synthesis,and inhibited the migration,invasion,and colony formation of cells.WFA also in.creased the apoptotic rate of cells,decreased the mitochondrial membrane potential,arrested cell cy.cle at G_2/M,inhibited the activity of caspase 3/7,and increased the protein expression of cleaved-cas.pase 3,cleaved PARP in U251 and U87-MG cells.In addition,cell apoptosis induced by WFA was as.sociated with increasing level of Bim,Bad,P21,P53 and decreasing the level of p-CDK1,cyclin A and B.It was also shown that cell apoptosis induced by WFA was associated with P38 signal pathway.These results demonstrated that WFA induced mitochondrial dependent apoptosis in glioblastoma cells which was associated with arresting the cell cycle at G_2/M phase by P38 pathway.Taken together,our findings suggest that WFA might be a promising chemotherapy drug in the treatment of GBM.