Letter | Published:

Cell mixing induced by myc is required for competitive tissue invasion and destruction

Nature volume 524, pages 476480 (27 August 2015) | Download Citation


Cell–cell intercalation is used in several developmental processes to shape the normal body plan1. There is no clear evidence that intercalation is involved in pathologies. Here we use the proto-oncogene myc to study a process analogous to early phase of tumour expansion: myc-induced cell competition2,3,4,5,6,7. Cell competition is a conserved mechanism5,6,8,9 driving the elimination of slow-proliferating cells (so-called ‘losers’) by faster-proliferating neighbours (so-called ‘winners’) through apoptosis10 and is important in preventing developmental malformations and maintain tissue fitness11. Here we show, using long-term live imaging of myc-driven competition in the Drosophila pupal notum and in the wing imaginal disc, that the probability of elimination of loser cells correlates with the surface of contact shared with winners. As such, modifying loser–winner interface morphology can modulate the strength of competition. We further show that elimination of loser clones requires winner–loser cell mixing through cell–cell intercalation. Cell mixing is driven by differential growth and the high tension at winner–winner interfaces relative to winner–loser and loser–loser interfaces, which leads to a preferential stabilization of winner–loser contacts and reduction of clone compactness over time. Differences in tension are generated by a relative difference in F-actin levels between loser and winner junctions, induced by differential levels of the membrane lipid phosphatidylinositol (3,4,5)-trisphosphate. Our results establish the first link between cell–cell intercalation induced by a proto-oncogene and how it promotes invasiveness and destruction of healthy tissues.

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We thank members of the Moreno laboratory for reading this manuscript. We also thank M. Bergen for help on E-cad fluorescence recovery after photobleaching (FRAP) data collection. We are also very grateful to Y. Bellaïche, O. Baumann, J. Grossahns, H. Jasper, T. Lecuit, L. Legoff, G. Morata, H. Stocker, R. Sousa-Nunes, the Bloomington stock center and the Developmental Studies Hybridoma Bank for sharing stocks and reagents, to B. Aigouy for the Packing analyser software and the Center for Microscopy and Image Analysis (University of Zurich) for sharing equipment. R.L. was supported by an EMBO long-term fellowship (ALTF 366-2012) and a Human Frontier post-doctoral fellowship (LT000178/2013). Work in our laboratory is funded by the European Research Council, the Swiss National Science Foundation, the Josef Steiner Cancer Research Foundation and the Swiss Cancer League.

Author information


  1. Institute for Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland

    • Romain Levayer
    • , Barbara Hauert
    •  & Eduardo Moreno


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R.L. and E.M. designed the experiments. R.L. performed and analysed the experiments. B.H. generated fwe knockout and fweloseA::mcherry knock-in flies. R.L. and E.M. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Eduardo Moreno.

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    Supplementary Information

    This file contains a Supplementary Discussion and additional references.


  1. 1.

    Live imaging of loser cells (wt in tub-dmyc)

    ubi-Ecad.::GFP (green, left) and UAS-mcd8::RFP (purple, wt loser cells in tub-dmyc background) in the pupal notum. White arrows point to delaminating cells (48h after clone induction, 20h after pupation). Note that the blurred signal moving in the background are out of focus macrophages. Scale bar=10μm.

  2. 2.

    Live imaging of wt cells (wt in wt)

    ubi-Ecad.::GFP (green) and UAS-mcd8::RFP (purple, wt cells in wt background) in the pupal notum. White arrows point to delaminating cells. Scale bar=10μm.

  3. 3.

    Live imaging of loser cell elimination (wt in tub-dmyc) in a wing disc

    Three examples of clones expressing ubi-Ecad.::GFP (green) and UAS-mcd8::RFP (purple, wt loser cells in tub-dmyc background) in ex-vivo cultured wing disc. The first frames show the full wing disc and the localisation of the clones. Movies stop when the clones get out of frame. Scale bar=5μm.

  4. 4.

    Live imaging of loser cells upon inhibition of apoptosis (UAS-diap1 in tub-dmyc)

    ubi-Ecad.::GFP (green) and UAS-mcd8::RFP (purple, UAS-diap1 loser cells in tub-dmyc background) in the pupal notum. White arrows point to spontaneous delamination occurring outside the clone. Note the absence of delamination in the clone. Scale bar=10μm.

  5. 5.

    Live imaging of cells overexpressing fewloseA

    ubi-Ecad.::GFP (green, and gray) and UAS-RFP (purple, UAS-fewloseA cells in wt background) in the pupal notum. White arrows point to loser delaminating cells. The first frames show the localisation of the clone (light blue). The RFP is not shown at later time point as it was rapidly bleached. Scale bar=10μm.

  6. 6.

    Live imaging of loser cells upon silencing of fewlose (UAS-fwelose RNAi in tub-dmyc)

    ubi-Ecad.::GFP (green) and UAS-mcd8::RFP (purple, UAS-fwelose RNAi loser cells in tub-dmyc background) in the pupal notum. White arrows point to delaminating cells. Scale bar=10μm.

  7. 7.

    Junction remodelling and cell intercalation at loser clone boundaries

    Two examples of persistent junction remodelling in the pupal notum leading to clone splitting (left) or to the loss of a loser/loser junction (right). ubi-Ecad.::GFP (green) and UAS-mcd8::RFP (purple, wt loser cells in tub-dmyc background). The initial junction topology is shown in blue, the final topology is shown in orange. Scale bar=10μm.

  8. 8.

    Junction remodelling in wt and tub-dmyc nota

    ubi-Ecad.::GFP in a wt pupal notum (left) or in a tub-dmyc notum (right). Purple junctions are disappearing junctions, green junctions are cell-cell interfaces still present after 10h. Scale bar=10μm.

  9. 9.

    F-actin dynamics in loser (wt in tub-dmyc) and winner junctions

    FRAPs of junctional sqh-utABD.::GFP in a loser-loser (left), a winner-winner (middle) or a winner-loser (right) junction in the pupal notum (wt loser cells in tub-dmyc). White circles show the bleached ROI. Scale bar=5μm.

  10. 10.

    Junction ablation in winner and loser junctions

    Junction relaxation after laser ablation in the pupal notum 48h after clone induction. Scale bars=2µm. First raw: supercompetition assay, winner-winner (left), loser-loser (middle) and winner-loser (right) junctions. ubi-Ecad.::GFP (green) and UAS-mcd8::RFP (purple, wt cells in tub-dmyc background). Second raw: Downregulation of PIP3 in clones. wt-wt (left), pi3kDN-pi3kDN (middle) and wt-pi3kDN (right) junctions. ubi-Ecad.::GFP (green) and UAS-RFP (purple, UAS-pi3kDN cells in wt background). Third raw: loser cells overexpressing Dia::GFP, winner-winner (left), loser-loser (middle) and winner-loser (right) junctions. ubi-Ecad.::GFP (gray) and UAS-diaGFP (gray, junction and cytoplasmic signal, UAS-dia::GFP cells in tub-dmyc background). Fourth raw: Loser cells after starvation, winner-winner (left), loser-loser (middle) and winner-loser (right) junctions. ubi-Ecad.::GFP (green) and UAS-mcd8::RFP (purple, wt cells in tub-dmyc background) in the pupal notum 48h after clone induction and 48h starvation. Note that the frame rate is different for this movie. Due to low signals, we also used a Kalman filter for a better display.

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