Up-regulated NRIP2 in colorectal cancer initiating cells modulates the Wnt pathway by targeting RORβ.
Up-regulated NRIP2 in colorectal cancer initiating cells modulates the Wnt pathway by targeting RORβ.
复制标题
结直肠癌起始细胞中上调的 NRIP2 通过靶向 ROR beta 调节 Wnt 通路
DOI：
10.1186/s12943-017-0590-2
复制
发表时间：
2017-01-31
期刊：
影响因子：
37.3
通讯作者：
Zhu Y
中科院分区：
文献类型：
--
作者：
Wen Z;Pan T;Yang S;Liu J;Tao H;Zhao Y;Xu D;Shao W;Wu J;Liu X;Wang Y;Mao J;Zhu Y
结直肠癌是世界范围内最常见的恶性肿瘤之一。结直肠癌起始细胞（CCICs）是导致结直肠癌恶性行为的一个小亚群。Wnt通路的异常激活调节CCIC的自我更新。然而，其潜在的机制仍然知之甚少。通过逆转录病毒文库筛选，我们发现核受体相互作用蛋白2 （NRIP2）是富集的结直肠癌结肠球细胞中Wnt通路的一个新的相互作用因子。采用FISH、qRT-PCR、免疫组化和Western blot检测NRIP2和视黄酸相关孤儿受体β (RORβ)的表达水平。制备过表达和敲低NRIP2的结直肠癌细胞，研究NRIP2在Wnt通路中的作用。我们还验证了NRIP2与RORβ之间的结合，并在体外和体内研究了RORβ对CCICs的影响。基因芯片扫描推测下游目标HBP1。采用Western blot、ChIP和荧光素酶报告基因检测NRIP2、RORβ和HBP1之间的相互作用。NRIP2在CCICs细胞系和原发性结直肠癌组织中均显著上调。NRIP2的增强表达增加了Wnt活性，而NRIP2的沉默则减弱了Wnt活性。转录因子RORβ是NRIP2调控Wnt通路活性的关键靶点。RORβ是Wnt通路中HBP1抑制剂的转录增强子。NRIP2阻止RORβ与下游HBP1启动子区域结合，减少HBP1的转录。这反过来又减弱了hbp1依赖性的tcf4介导的转录抑制。NRIP2是结直肠癌起始细胞中Wnt通路的一个新的相互作用因子。NRIP2、RORβ和HBP1之间的相互作用介导了CCIC通过Wnt活性自我更新的新机制。本文的在线版本（doi:10.1186/s12943-017-0590-2）包含补充材料，可供授权用户使用。
Colorectal cancer remains one of the most common malignant tumors worldwide. Colorectal cancer initiating cells (CCICs) are a small subpopulation responsible for malignant behaviors of colorectal cancer. Aberrant activation of the Wnt pathways regulates the self-renewal of CCIC. However, the underlying mechanism(s) remain poorly understood. Via retroviral library screening, we identified Nuclear Receptor-Interacting Protein 2 (NRIP2) as a novel interactor of the Wnt pathway from enriched colorectal cancer colosphere cells. The expression levels of NRIP2 and retinoic acid-related orphan receptor β (RORβ) were further examined by FISH, qRT-PCR, IHC and Western blot. NRIP2 overexpressed and knockdown colorectal cancer cells were produced to study the role of NRIP2 in Wnt pathway. We also verified the binding between NRIP2 and RORβ and investigated the effect of RORβ on CCICs both in vitro and in vivo. Genechip-scanning speculated downstream target HBP1. Western blot, ChIP and luciferase reporter were carried to investigate the interaction between NRIP2, RORβ, and HBP1. NRIP2 was significantly up-regulated in CCICs from both cell lines and primary colorectal cancer tissues. Reinforced expression of NRIP2 increased Wnt activity, while silencing of NRIP2 attenuated Wnt activity. The transcription factor RORβ was a key target through which NRIP2 regulated Wnt pathway activity. RORβ was a transcriptional enhancer of inhibitor HBP1 of the Wnt pathway. NRIP2 prevented RORβ to bind with downstream HBP1 promoter regions and reduced the transcription of HBP1. This, in turn, attenuated the HBP1-dependent inhibition of TCF4-mediated transcription. NRIP2 is a novel interactor of the Wnt pathway in colorectal cancer initiating cells. interactions between NRIP2, RORβ, and HBP1 mediate a new mechanism for CCIC self-renewal via the Wnt activity. The online version of this article (doi:10.1186/s12943-017-0590-2) contains supplementary material, which is available to authorized users.