shRNA-Mediated Silencing of Y-Box Binding Protein-1 (YB-1) Suppresses Growth of Neuroblastoma Cell SH-SY5Y In Vitro and In Vivo.

Y-box binding protein-1 (YB-1)， a member of cold-shock protein superfamily， has been demonstrated to be associated with tumor malignancy， and is proposed as a prognostic marker in multiple carcinomas. However， the role of YB-1 in neuroblastoma has not been well studied. To investigate the functional role of YB-1 in neuroblastoma， we established a YB-1-silenced neuroblastoma cell strain by inhibiting YB-1 expression using a shRNA knockdown approach. YB-1-silenced neuroblastoma SH-SY5Y cells exhibited a pronounced reduction in cell proliferation and an increased rate of apoptosis in vitro and in vivo xenograft tumor model. At molecular level， YB-1 silencing resulted in downregulation of Cyclin A， Cyclin D1 and Bcl-2， as well as upregulated levels of Bax， cleaved caspase-3 and cleaved PARP-1. We further demonstrated that YB-1 transcriptionally regulated Cyclin D1 expression by chromatin-immunoprecipitation and luciferase reporter assays. In addition， xenograft tumors derived from neuroblastoma SH-SY5Y cell line were treated with YB-1 shRNA plasmids by intra-tumor injection， and YB-1 targeting effectively inhibited tumor growth and induced cell death. In summary， our findings suggest that YB-1 plays a critical role in neuroblastoma development， and it may serve as a potential target for neuroblastoma therapy.