Gastroenterology

Gastroenterology

Volume 129, Issue 4, October 2005, Pages 1225-1236
Gastroenterology

Basic-alimentary tract
β-Catenin Interacts With the FUS Proto-oncogene Product and Regulates Pre-mRNA Splicing

https://doi.org/10.1053/j.gastro.2005.07.025Get rights and content

Background & Aims: β-Catenin is a downstream effector of the Wnt signaling pathway and is believed to exert its oncogenic function by activating T-cell factor (TCF)/lymphoid enhancer factor (LEF) family transcriptional factors. However, it is still uncertain whether the diverse effects of β-catenin are caused solely by aberrant gene transactivation. In this study, we used a proteomics approach to obtain further insight into the functional properties of nuclear β-catenin. Methods: The protein assembly of a native β-catenin-containing complex in nuclear extracts from a colorectal cancer cell line, DLD-1, was identified using immunoprecipitation and mass spectrometry. Results: β-Catenin physically interacted with fusion (FUS)/translocated in liposarcoma (TLS) and various RNA-binding proteins. The expression of FUS/TLS was closely associated with the accumulation of β-catenin and with the undifferentiated status of intestinal epithelial cells. The transient transfection of FUS suppressed β-catenin-evoked gene transactivation of TCF/LEF, and β-catenin transfection affected the splicing pattern of the E1A minigene and induced a novel splicing variant of estrogen receptor (ER)-β exerting a dominant-negative activity. Conclusions: Human cancer expresses a large variety of alternatively spliced messenger RNA (mRNA), but the precise molecular mechanisms responsible for cancer-related alternative splicing are largely unknown. In this study, we demonstrated the interaction of β-catenin with FUS/TLS and other RNA-binding proteins involved in the regulation of pre-mRNA splicing. Certain mRNA splicing abbreviations seen in human cancers may be induced by the activation of the Wnt signaling pathway.

Section snippets

Cell Lines

Human embryonic kidney (HEK) cell line 293 and human colorectal cancer cell lines DLD-1, RCM-1, LoVo, COLO320, CCK-81, SW837, and COLO201 were obtained from the Health Science Research Resources Bank (Osaka, Japan). Human cervical cancer cell line HeLa, human breast cancer cell lines MCF-7 and MDA-MB-435, and simian kidney epithelial cell line Cos-7 were purchased from the Riken Cell Bank (Tsukuba, Japan). Human colorectal cancer cell lines SW48, LS174T, HT-29, SW1116, HCT-8, HCT-116, SW403,

Assembly of β-Catenin-Containing Nuclear Complex in a Colorectal Cancer Cell Line

At least 12 proteins in addition to β-catenin were constantly immunoprecipitated by the anti-β-catenin antibody, but not by normal control mouse IgG, from nuclear extracts obtained from a colorectal adenocarcinoma cell line, DLD-1 (Figure 1A). DLD-1 cells accumulate β-catenin protein as a result of a truncational mutation and loss of heterozygosity (LOH) in the APC genes.5 Mass spectrometric analysis revealed that these proteins included DNA topoisomerase IIα (TOP2A), DEAD-box RNA helicases

Discussion

In this study, we demonstrated the physical interaction of a protooncogene product, β-catenin, with another protooncogene product, FUS (Figure 1, Figure 2, Figure 3). The expression level of FUS protein decreased gradually from the bottom to the surface of the intestinal crypts (Figure 4A–D). The expression pattern of FUS in the adenoma cells completely paralleled that of accumulated β-catenin protein (Figure 4E–H). The FUS protein was strongly expressed in the nuclei of adenocarcinoma cells

References (39)

  • S. Inoue et al.

    An estrogen receptor β isoform that lacks exon 5 has dominant negative activity on both ERα and ERβ

    Biochem Biophys Res Commun

    (2000)
  • Q. Tanko et al.

    A hMLH1 genomic mutation and associated novel mRNA defects in a hereditary non-polyposis colorectal cancer family

    Mutat Res

    (2002)
  • W.J. Nelson et al.

    Convergence of Wnt, β-catenin, and cadherin pathways

    Science

    (2004)
  • R.T. Moon et al.

    The promise and perils of Wnt signaling through β-catenin

    Science

    (2002)
  • A. Kikuchi

    Tumor formation by genetic mutations in the components of the Wnt signaling pathway

    Cancer Sci

    (2003)
  • P.J. Morin et al.

    Activation of β-catenin-Tcf signaling in colon cancer by mutations in β-catenin or APC

    Science

    (1997)
  • A.B. Sparks et al.

    Mutational analysis of the APC/β-catenin/Tcf pathway in colorectal cancer

    Cancer Res

    (1998)
  • T. Yamada et al.

    Transactivation of the multidrug resistance 1 gene by T-cell factor 4/β-catenin complex in early colorectal carcinogenesis

    Cancer Res

    (2000)
  • N. Harada et al.

    Intestinal polyposis in mice with a dominant stable mutation of the β-catenin gene

    EMBO J

    (1999)
  • Cited by (66)

    • Carcinoembryonic antigen promotes colorectal cancer progression by targeting adherens junction complexes

      2014, Experimental Cell Research
      Citation Excerpt :

      In this study, we identified CEAR/hnrnp M protein as a binding partner for α-catenin protein in MIP101 colorectal carcinoma cells. In support of our data Sato et al. [29] showed that CEAR/hnRNP M protein can physically interact with β-catenin in DLD-1 colorectal carcinoma cells. Sato et al. also demonstrated that the hnRNPM/β-catenin/FUS/TLS complex participates to regulate pre-mRNA splicing and that activation of the Wnt signaling pathway may induce certain mRNA-splicing abbreviations seen in human cancers [29].

    • Heme oxygenase-1 regulates postnatal lung repair after hyperoxia: Role of β-catenin/hnRNPK signaling

      2013, Redox Biology
      Citation Excerpt :

      Altogether, these data suggest that the nuclear form of HO-1 binds hnRNPK and retains this protein in the nuclear compartment. The β-catenin and hnRNP proteins work in concert to modify gene expression important to cellular proliferation and DNA repair [36]. Perhaps this could help explain the drastic alteration in cell proliferation and cell cycle genes observed in the O2/air recovered KO (Fig. 3B).

    View all citing articles on Scopus

    Supported by a grant from the Ministry of Health, Labor, and Welfare and by the “Program for Promotion of Fundamental Studies in Health Sciences” of the National Institute of Biological Innovation of Japan.

    View full text