title: Down-regulation of 14-3-3β exerts anti-cancer effects through inducing ER stress in human glioma U87 cells: Involvement of CHOP-Wnt pathway.
abstract: We previously identified 14-3-3β as a tumor-specific isoform of 14-3-3 protein in astrocytoma, but its functional role in glioma cells and underlying mechanisms are poorly understood. In the present study, we investigated the effects of 14-3-3β inhibition in human glioma U87 cells using specific targeted small interfering RNA (siRNA). The results showed that 14-3-3β is highly expressed in U87 cells but not in normal astrocyte SVGp12 cells. Knockdown of 14-3-3β by Si-14-3-3β transfection significantly decreased the cell viability but increased the LDH release in a time-dependent fashion in U87 cells, and these effects were accompanied with G0/G1 cell cycle arrest and apoptosis. In addition, 14-3-3β knockdown induced ER stress in U87 cells, as evidenced by ER calcium release, increased expression of XBP1S mRNA and induction of ER related pro-apoptotic factors. Down-regulation of 14-3-3β significantly decreased the nuclear localization of β-catenin and inhibited Topflash activity, which was shown to be reversely correlated with CHOP. Furthermore, Si-CHOP and sFRP were used to inhibit CHOP and Wnt, respectively. The results showed that the anti-cancer effects of 14-3-3β knockdown in U87 cells were mediated by increased expression of CHOP and followed inhibition of Wnt/β-catenin pathway. In summary, the remarkable efficiency of 14-3-3β knockdown to induce apoptotic cell death in U87 cells may find therapeutic application for the treatment of glioma patients.
authors.affiliation: Department of Neurological Disease, Xi'an Central Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Cao
authors.affiliation: Department of Neurological Disease, Xi'an Central Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Lei
authors.affiliation: Department of Neurological Disease, Xi'an Central Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China.
authors.forename: Ming-Ze
authors.initials: MZ
authors.lastname: Chang
authors.affiliation: Department of Neurological Disease, Xi'an Central Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710000, China.
authors.forename: Zhi-Qin
authors.initials: ZQ
authors.lastname: Liu
authors.affiliation: Department of Functional Neurosurgery, Xi'an Red Cross Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China. Electronic address: biexiaohua_xjtu@126.com.
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Bie
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis; D001483:Base Sequence; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D017931:DNA Primers; D015536:Down-Regulation; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D018384:Oxidative Stress; D060888:Real-Time Polymerase Chain Reaction; D051742:Transcription Factor CHOP / Q000378:metabolism*; D051153:Wnt Proteins / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; C497249:DDIT3 protein, human; D017931:DNA Primers; D051153:Wnt Proteins; C482982:YWHAB protein, human; D051742:Transcription Factor CHOP
keywords: 14-3-3β; CHOP; ER stress; U87 cells; Wnt