title: Up-regulated NRIP2 in colorectal cancer initiating cells modulates the Wnt pathway by targeting RORβ.
abstract: 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.
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.|Present address: Department of Gastroenterology, Sir Run Run Shaw Hospital of Zhejiang, University School of Medicine, Hangzhou, Zhejiang, 310016, China.
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Wen
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.
authors.forename: Tianhui
authors.initials: T
authors.lastname: Pan
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.
authors.forename: Saisai
authors.initials: S
authors.lastname: Yang
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Liu
authors.affiliation: People's Hospital of Huangyan district, Taizhou, Zhejiang, 318020, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Tao
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.
authors.forename: Dingting
authors.initials: D
authors.lastname: Xu
authors.affiliation: People's Hospital of Putuo district, Zhoushan, Zhejiang, 316100, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shao
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, CA, 62232, USA.
authors.forename: Xiyong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China.
authors.forename: Yongjiang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China. jshmao@zju.edu.cn.|Cancer Institute and Education Ministry Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China. jshmao@zju.edu.cn.
authors.forename: Jianshan
authors.initials: J
authors.lastname: Mao
authors.affiliation: Laboratory of Gastroenterology, Second Affiliated Hospital of Zhejiang University School of Medicine, Jiefang Road 88#, Hangzhou, Zhejiang, 310009, China. drylzhu@163.com.|Cancer Institute and Education Ministry Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China. drylzhu@163.com.
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Zhu
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D019073:HT29 Cells; D006609:High Mobility Group Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D051379:Mice; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D057095:Nuclear Receptor Subfamily 1, Group F, Member 2 / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation; D060449:Wnt Signaling Pathway
chemical_list: D004268:DNA-Binding Proteins; C486328:HBP1 protein, human; D006609:High Mobility Group Proteins; D009419:Nerve Tissue Proteins; C411289:Nrip2 protein, mouse; D057095:Nuclear Receptor Subfamily 1, Group F, Member 2; C539740:RORB protein, human; D012097:Repressor Proteins
keywords: Colorectal cancer initiating cells; HBP1; NRIP2; Non-canonical Wnt pathway; RORβ; Self-renewal