β-catenin核易位遏制人甲状腺癌细胞中钠碘转运体膜定位的实验观察  

Nuclear translocation of β-catenin represses membrane localization of NIS in human thyroid cancer cells

作　　者：兰玲[1] 邓微[1] 陈海翎[1] 霍丽丽[1] 邓丽丽[1] 张国英[1] 罗勇[2] 

机构地区：[1]北京积水潭医院内分泌科,100035 [2]首都医科大学附属北京安贞医院泌尿外科

出　　处：《中华医学杂志》2016年第11期891-896,共6页National Medical Journal of China

基　　金：国家自然科学基金（81372858、30700968）

摘　　要：目的 观察β连环素（β-catenin）核易位能否影响甲状腺癌细胞中钠碘转运体（NIS）的功能性表达.方法 分别将缺氧诱导因子1α（HIF-1α）和β-catenin cDNA转染人甲状腺癌细胞株FTC133,建立两种β-catenin核易位模型.进而再分别转染pSUPER/β-catenin封闭质粒,建立两种干预模型.Western印迹、Transwell、MTT、免疫荧光染色及摄碘实验分别用于检测β-catenin核易位前后相关蛋白、细胞体外侵袭、增殖、摄碘能力的变化,以及NIS表达部位与β-catenin核易位的关系.制作重症联合免疫缺陷（SCID）小鼠皮下瘤模型,观察肿瘤生长曲线、肿瘤质量及对放射性碘治疗反应等变化.结果 HIF-1α转染及β-catenin转染细胞中均出现了典型的上皮细胞间质转化的蛋白表达谱,且体外增殖和侵袭能力增强近2倍（均P＜0.05）;NIS蛋白由膜表达向胞质表达转变,细胞摄碘率分别下降50.0％和37.5％（均P＜0.05）,并且这种核易位变化与β-catenin Ser45、Y654以及GSK-3β Ser9位点磷酸化有关;β-catenin表达封闭后,这些变化均有效逆转.动物实验也发现,β-catenin表达封闭及131I处理均能遏制瘤体的生长能力（均P＜0.05）;免疫组化染色提示,瘤体细胞显示与接种细胞一致的β-catenin核易位状态,并与NIS膜表达负相关.结论 β-catenin核易位是人甲状腺癌中NIS功能性表达的重要调控途径.Objective To explore whether nuclear translocation of β-catenin affects functional expression of sodium iodide symporter （NIS） in human thyroid cancer cells.Methods Two kinds of β-catenin nuclear translocation cell models were firstly established with transfection of hypoxia inducible factor 1α （HIF-1α） and β-catenin cDNA in human thyroid cancer cell line FTC133.Then the expression of β-catenin were further interfered by shRNA in above two cell models.After that,the influence of β-catenin nuclear localization on the functional expression of NIS,iodine uptake potency,epithelial-mesenchymal transition （EMT） characteristics,tumor growth curve and treatment effect inducing by radioactive iodine were comparatively analyzed in vitro and in vivo trials.Additionally,the underlying mechanism of NIS functional expression was also assessed via identifying the activation of β-catenin signal pathway.Results In vitro assay showed prominent EMT phenotype in the above two β-catenin nuclear translocation cell models,and in vitro proliferation and invasion potential of cancer cells markedly increased （all P ＜ 0.05）;NIS protein expression translocated from cell membrane to cytoplasma.Cell iodide uptake in vitro decreased about 50.0％ and 37.5％,respectively in above two β-catenin translocation cell models （both P＜0.05）.Moreover,β-catenin nuclear translocation was correlated with phosphorylation expressions of β-catenin Ser45,Y654 and GSK-3β Ser9.Most importantly,all above changes associated with β-catenin nuclear translocation could be effectively reversed after blockade of β-catenin expression.In the animal model,tumor growth potential and tumor mass were significantly inhibited by both blockade of β-catenin and radioactive iodide （131I） （all P ＜ 0.05）.Meanwhile,immunohistochemistry demonstrated that β-catenin nuclear translocation remained in subcutaneous tumor cells after transplantation,and showed negatively associated with NIS membrane expression.Conclusion β-catenin nuclea

关 键 词：甲状腺肿瘤 Β连环素 钠碘转运体 碘放射性同位素 上皮细胞间质转化 

分 类 号：R736.1[医药卫生—肿瘤]