连接桥粒斑珠蛋白抑制神经母细胞瘤Wnt/β-catenin信号通路活化和增殖、侵袭作用及机制

Junctional plakoglobin inhibits Wnt/β-catenin signaling,proliferation and invasion of neuroblastoma and its underlying mechanisms

目的探讨连接桥粒斑珠蛋白(JUP)在神经母细胞瘤增殖、侵袭中发挥的作用及其机制。方法检测神经母细胞瘤临床组织标本及细胞系中的JUP蛋白水平。过表达及敲低JUP前后采用蛋白印迹法、实时定量PCR检测基因表达变化,运用MTT比色分析、基质胶侵袭实验观测瘤细胞的增殖、侵袭能力变化;运用免疫共沉淀、荧光素酶报告基因方法观测蛋白相互作用及Wnt/β-catenin信号通路活化改变。结果神经母细胞瘤临床组织标本中JUP低表达,与神经母细胞瘤的不良预后相关。MYCN扩增型神经母细胞瘤细胞中JUP水平更低(P<0.05);过表达JUP对神经母细胞瘤细胞的增殖、侵袭起到抑制作用(均P<0.05);JUP能与β-catenin相结合,减少β-catenin进入细胞核,抑制Wnt/β-catenin信号通路活性。结论JUP在神经母细胞瘤中通过与β-catenin相互作用并抑制其核转位,降低Wnt/β-catenin信号通路活性,抑制神经母细胞瘤的增殖、侵袭。

Objective To investigate the roles and mechanism of junctional plakoglobin(JUP)in the proliferation and invasion of neuroblastoma(NB).Methods The expression of JUP was investigated in clinical NB tissues and cultured cell lines.After over-expression or knockdown of JUP,its expression was validated by western blot and real-time quantitative PCR.The alteration in cellular viability and invasion was studied by MTT colorimetric and matrigel invasion assays.Protein interaction and activation of Wnt/β-catenin were measured by co-immunoprecipitation and luciferase reporter assays.Results JUP was down-regulated in NB,which was associated with poor prognosis of patients.JUP was down-regulated in NB cell lines with MYCN amplification(P<0.05).Over-expression of JUP inhibited the proliferation and invasion capabilities of NB cells(all P<0.05).JUP interacted withβ-catenin,resulting in decreased nuclear entry ofβ-catenin and repressed activation of Wnt/β-catenin signaling.Conclusions JUP interacts withβ-catenin to inhibit its nuclear translocation,reduces the activity of Wnt/β-catenin signaling pathway,and inhibits the proliferation and invasion of NB.