Resveratrol promotes proteasome-dependent degradation of Nanog via p53 activation and induces differentiation of glioma stem cells

Glioblastoma is the most common and aggressive primary brain tumor. Glioma stem cells (GSCs) are relatively resistant to chemo-radiotherapy and are responsible for tumor progression and the recurrence of glioblastomas after conventional therapy. Thus, the control of the GSC population is considered key to realizing long-term survival of glioblastoma patients. Here, we identified that resveratrol significantly reduced the self-renewal and tumor-initiating capacity of patient-derived GSCs. Furthermore, resveratrol promoted Nanog suppression via proteasomal degradation, which was inhibited by MG132, a proteasome inhibitor. p53 activation is an important factor in Nanog suppression and treatment with resveratrol was also found to activate the p53/p21 pathway. Importantly, inhibition of Nanog by siRNA provoked inhibitory effects on both the self-renewal and tumor-forming capacity of GSCs. Our findings indicate that Nanog is an essential factor for the retention of stemness and may contribute to the resveratrol-induced differentiation of GSCs. Our results also suggest that targeting GSCs via the p53-Nanog axis, with resveratrol for instance, could be a therapeutic strategy against glioblastoma. (C) 2013 Elsevier B.V. All rights reserved.