The FBXW7 β-form is suppressed in human glioma cells

https://doi.org/10.1016/j.bbrc.2007.01.080Get rights and content

Abstract

FBXW7 (F-box and WD40 domain protein 7) is an F-box protein with 7 tandem WDs (tryptophan–aspartic acid) that functions as a phosphoepitope-specific substrate recognition component of SCF (Skp1–Cul1–F-box protein) ubiquitin ligases and catalyzes the ubiquitination of proteins promoting cell proliferation, such as CCNE1, MYC, AURKA, NOTCH1, and JUN, which are frequently activated in a wide range of human cancers. FBXW7 is a candidate tumor suppressor, and mutations have been reported in some human tumors. In this study, we analyzed 84 human tumor cell lines in search for genetic alterations of FBXW7, as well as mRNA and protein expressional changes, and compared them with expression levels of the CCNE1, MYC, and AURKA proteins. We found a novel nonsense mutation in a colon cancer cell line SCC and confirmed the missense mutations in SKOV3, an ovarian cancer cell line, and LoVo, a colon cancer cell line. Moreover, suppressed expression of FBXW7 accompanied by activation of the target proteins were observed in ovarian, colon, endometrial, gastric, and prostate cancers. It is notable that highly suppressed mRNA expression of the FBXW7 β-form was found in all the human glioma cell lines analyzed; enhanced expressions of CCNE1, MYC, and AURKA were observed in these cells. Our present results imply that FBXW7 plays a pivotal role in many tissues by controlling the amount of cell cycle promoter proteins and that dysfunction of this protein is one of the essential steps in carcinogenesis in multiple organs.

Section snippets

Materials and methods

Cell lines and normal tissues. A total of 84 human cancer cell lines were analyzed in this study; 21 lung cancer cell lines (1–87, 11–18, 86–2, ABC-1, H1299, LCSC#1, LCSC#2, LK79, LK87, Lu65, Lu99A, Lu99B, RERF-LC-MS, RERF-LC-OK, Sato T, S-2, SBC3, Sq-1, Sq19, VMRC-LCD, VMRC-LCP), 28 pancreatic cancer cell lines (PK-1, PK-8, PK-9, PK-12, PK-14, PK-16, PK-36, PK-45 P, PK-45 H, PK-47, PK-59, PK-65, PK-66, PK-67, PAN03JCK, PAN07JCK, PAN08JCK, PAN09JCK, PCI-6, PCI-19, PCI-24, PCI-35, PCI-43, PCI-55,

Mutation analyses

In this study, we analyzed a total of 84 human tumor cell lines originating from 10 different organs. Mutations of the entire exonic regions (exons α, β, and γ, corresponding to the first exon for each of the α-, β-, and γ-forms of the transcript, and the common exons 2 through 11) of the FBXW7 gene were sought by sequencing the genomic DNAs from these cells. One colon cancer cell line, SCC, harbored a novel nonsense mutation (R393X) in exon 7 (Fig. 1A). No signal corresponding to the normal

Discussion

FBXW7, the gene that encodes the F-box protein responsible for targeting cell cycle accelerators such as CCNE1, AURKA, and MYC for ubiquitin-mediated proteolysis [1], has been found to be mutated in a number of primary cancers and cancer-derived cell lines [5], [12], [13], [14], [15], [16], [36]. In this study, we searched for FBXW7 mutations in 84 cell lines derived from 10 organs and found mutations in two of 10 (20%) colon cancer cell lines and one of seven (14%) ovarian cancer cell lines.

Acknowledgments

We thank Dr. Barbara Lee Smith Pierce (Adjunct Professor with the University of Maryland University College) for editorial work in the preparation of this manuscript. This work was supported in part by Grants-in-Aid and the 21st Century COE Program Special Research Grant from the Ministry of Education, Culture, Sports, Science and Technology of Japan, and by a Grant-in-Aid for Cancer Research from the Ministry of Health, Labour and Welfare of Japan.

References (37)

  • M. Welcker et al.

    The Fbw7 tumor suppressor regulates glycogen synthase kinase 3 phosphorylation -dependent c-Myc protein degradation

    Proc. Natl. Acad. Sci. USA

    (2004)
  • J.H. Mao et al.

    Fbxw7/Cdc4 is a p53-dependent, haploinsufficient tumour suppressor gene

    Nature

    (2004)
  • G. Wu et al.

    SEL-10 is an inhibitor of notch signaling that targets notch for ubiquitin-mediated protein degradation

    Mol. Cell Biol.

    (2001)
  • A.S. Nateri et al.

    The ubiquitin ligase SCFFbw7 antagonizes apoptotic JNK signaling

    Science

    (2004)
  • C.H. Spruck et al.

    hCDC4 gene mutations in endometrial cancer

    Cancer Res.

    (2002)
  • A. Sterian et al.

    Mutational and LOH analyses of the chromosome 4q region in esophageal adenocarcinoma

    Oncology

    (2006)
  • K.H. Moberg et al.

    Archipelago regulates cyclin E levels in Drosophila and is mutated in human cancer cell lines

    Nature

    (2001)
  • R. Cassia et al.

    Cyclin E gene (CCNE) amplification and hCDC4 mutations in endometrial carcinoma

    J. Pathol.

    (2003)
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