Interferon-induced transmembrane 3 binds osteopontin in vitro: expressed in vivo IFITM3 reduced OPN expression
Interferon-induced transmembrane 3 binds osteopontin in vitro: expressed in vivo IFITM3 reduced OPN expression
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DOI：
10.1038/onc.2009.379
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发表时间：
2010-02-04
期刊：
影响因子：
8
通讯作者：
Johnston, P. G.
中科院分区：
文献类型：
--
作者：
El-Tanani, M. K.;Jin, D.;Johnston, P. G.
骨桥蛋白是一种分泌型、整合素结合和磷酸化的酸性糖蛋白，在肿瘤的发展中起着重要的作用。我们已经证明，Wnt、Ets、AP-1、c-jun和β-catenin/Lef-1/Tcf-1通过与特定的启动子序列结合来刺激大鼠乳腺癌细胞中OPN的转录。然而，OPN的共抑制因子尚未确定。在这项研究中，我们使用细菌双杂交系统来分离与骨桥蛋白结合并调节其在恶性转化中的作用的编码蛋白。利用这种方法，我们分离了干扰素诱导的跨膜蛋白3基因(IFITM3)，作为一个潜在的蛋白质伙伴。我们发现IFITM3和OPN在体外和体内相互作用，并且IFITM3可能通过影响OPN mRNA的稳定性来降低骨桥蛋白(OPN)的mRNA表达。稳定的IFITM3基因可以抑制骨桥蛋白的表达，而骨桥蛋白介导的是锚定非依赖性生长、细胞黏附和细胞侵袭。Northern印迹分析显示，IFITM3和OPN在人乳腺细胞系中的表达模式相反。反义RNA抑制IFITM3可促进OPN蛋白的表达，增强亲本良性非侵袭性RAMA 37细胞的侵袭力，表明两种蛋白在功能上存在相互作用。我们还发现了一个IFITM3DNA结合域，它与OPN相互作用，缺失后就失去了它对OPN的抑制作用。这项工作首次表明IFITM3与OPN发生物理作用并减少OPN的表达，在大鼠模型系统中介导细胞黏附、细胞侵袭、软琼脂集落形成和转移。Oncogene(2010年)29752762；doi：10.1038/onc.2009.379；2009年11月9日在线发布
Osteopontin is a secreted, integrin-binding and phosphorylated acidic glycoprotein, which has an important role in tumour progression. We have shown that Wnt, Ets, AP-1, c-jun and beta-catenin/Lef-1/Tcf-1 stimulates OPN transcription in rat mammary carcinoma cells by binding to a specific promoter sequence. However, co-repressors of OPN have not been identified. In this study, we have used the bacterial two-hybrid system to isolate cDNA-encoding proteins that bind to OPN and modulate its role in malignant transformation. Using this approach we isolated interferon-induced transmembrane protein 3 gene (IFITM3) as a potential protein partner. We show that IFITM3 and OPN interact in vitro and in vivo and that IFITM3 reduces osteopontin (OPN) mRNA expression, possibly by affecting OPN mRNA stability. Stable transfection of IFITM3 inhibits OPN, which mediates anchorage-independent growth, cell adhesion and cell invasion. Northern blot analysis revealed an inverse mRNA expression pattern of IFITM3 and OPN in human mammary cell lines. Inhibition of IFITM3 by antisense RNA promoted OPN protein expression, enhanced cell invasion by parental benign non-invasive Rama 37 cells, indicating that the two proteins interact functionally as well. We also identified an IFITM3 DNA-binding domain, which interacts with OPN, deletion of which abolished its inhibitive effect on OPN. This work has shown for the first time that IFITM3 physically interacts with OPN and reduces OPN mRNA expression, which mediates cell adhesion, cell invasion, colony formation in soft agar and metastasis in a rat model system. Oncogene (2010) 29, 752-762; doi: 10.1038/onc.2009.379; published online 9 November 2009