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Characterization of the interface between normal and transformed epithelial cells

Nature Cell Biology volume 11, pages 460467 (2009) | Download Citation



In most cancers, transformation begins in a single cell in an epithelial cell sheet1,2,3. However, it is not known what happens at the interface between non-transformed (normal) and transformed cells once the initial transformation has occurred. Using Madin-Darby canine kidney (MDCK) epithelial cells that express constitutively active, oncogenic Ras (RasV12) in a tetracycline-inducible system, we investigated the cellular processes arising at the interface between normal and transformed cells. We show that two independent phenomena occur in a non-cell-autonomous manner: when surrounded by normal cells, RasV12 cells are either apically extruded from the monolayer, or form dynamic basal protrusions and invade the basal matrix. Neither apical extrusion nor basal protrusion formation is observed when RasV12 cells are surrounded by other RasV12 cells. We show that Cdc42 and ROCK (also known as Rho kinase) have vital roles in these processes. We also demonstrate that E-cadherin knockdown in normal cells surrounding RasV12 cells reduces the frequency of apical extrusion, while promoting basal protrusion formation and invasion. These results indicate that RasV12-transformed cells are able to recognize differences between normal and transformed cells, and consequently leave epithelial sheets either apically or basally, in a cell-context-dependent manner.

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We thank G. K. Ojakian for the anti-gp135 antibody, A. Hall, A. Lloyd, R. Y. Tsien, S. Lowe and E. Sahai for constructs, and A. Vaughan for technical assistance with microscopes. We also thank Y. Morishita for discussion on physical forces at cell–cell adhesions. S.D-C. was supported by a FEBS Long Term Fellowship. A.E.P. acknowledges the Interdisciplinary Research Collaboration (IRC) in Nanotechnology (Cambridge, EPSRC UK) and the Dr Mortimer and Theresa Sackler Trust for financial support. This work is supported by MRC funding of the Cell Biology Unit.

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Author notes

    • Sophie Dupré-Crochet

    Current address: INSERM UMR 757, Université Paris-sud, Bat 443, 91405 Orsay cedex, France.


  1. MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, Gower Street, London, WC1E 6BT, UK.

    • Catherine Hogan
    • , Sophie Dupré-Crochet
    • , Mark Norman
    • , Mihoko Kajita
    • , Carola Zimmermann
    • , Franck Pichaud
    •  & Yasuyuki Fujita
  2. Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.

    • Franck Pichaud
    •  & Yasuyuki Fujita
  3. London Centre for Nanotechnology and Centre for Nanomedicine, 17–19 Gordon Street, London, WC1H 0AH, UK.

    • Andrew E. Pelling
  4. Division of Developmental Neurobiology, National Institute for Medical Research, London, NW7 1AA, UK.

    • Eugenia Piddini
    • , Luis Alberto Baena-López
    •  & Jean-Paul Vincent
  5. Imperial College London, The Kennedy Institute of Rheumatology, 1 Aspenlea Road, London, W6 8LH, UK.

    • Yoshifumi Itoh
  6. Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739–8526, Japan.

    • Hiroshi Hosoya


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C.H. designed the experiments and generated most of the data; S.D-C. established stable MDCK cell lines and performed statistical analyses (Fig. 1d); M.N. analysed clonal expression of RasV12, RasN17 and RasWT in Drosophila wing imaginal discs (Fig. 1e and Supplementary Information, Fig. S3); M.K. performed western blot analyses (Supplementary Information, Fig. S1b), immunofluorescence studies (Supplementary Information, Fig. S4a) and established stable MDCK cell lines; C.Z. performed western blot and time-lapse analyses (Supplementary Information, Figs S2a, d and S5e), and established stable MDCK cell lines; A.E.P. performed AFM experiments and analyses (Supplementary Information, Fig. S9); E.P., L.A.B-L. and J-P.V. analysed clonal expression of RasV12, RasN17 and RasWT in Drosophila wing imaginal discs (Fig. 1e and Supplementary Information, Fig. S3); Y.I. provided technical expertise on use of collagen; H.H. provided technical expertise on myosin-II; F.P. assisted with Drosophila experiments; Y.F. conceived and designed the study and acted as principal investigator.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Yasuyuki Fujita.

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