Abstract
The metastatic progression of cancer is a multi-step process initiated by the local invasion of the peritumoral stroma. To identify the mechanisms underlying colorectal carcinoma (CRC) invasion, we collected live human primary cancer specimens at the time of surgery and monitored them ex vivo. This revealed that conventional adenocarcinomas undergo collective invasion while retaining their epithelial glandular architecture with an inward apical pole delineating a luminal cavity. To identify the underlying mechanisms, we used microscopy-based assays on 3D organotypic cultures of Caco-2 cysts as a model system. We performed two siRNA screens targeting Rho-GTPases effectors and guanine nucleotide exchange factors. These screens revealed that ROCK2 inhibition triggers the initial leader/follower polarization of the CRC cell cohorts and induces collective invasion. We further identified FARP2 as the Rac1 GEF necessary for CRC collective invasion. However, FARP2 activation is not sufficient to trigger leader cell formation and the concomitant inhibition of Myosin-II is required to induce invasion downstream of ROCK2 inhibition. Our results contrast with ROCK pro-invasive function in other cancers, stressing that the molecular mechanism of metastatic spread likely depends on tumour types and invasion mode.
| Original language | English |
|---|---|
| Article number | e99299 |
| Journal | EMBO Journal |
| Volume | 38 |
| Issue number | 14 |
| DOIs | |
| State | Published - 15 Jul 2019 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2019 The Authors
Funding
This work is dedicated to the memory of Alan Hall, an inspiring scientist and mentor. We thank Pr. Xuewu Zhang (University of Texas, USA) for providing us with the FARP1 and FARP2 constructs (He et al, 2013) which we used to generate lentiviral-based expression vectors, Pr. Yoshimi Takai (Kobe University, Japan) for the pEGFP-FARP2, Fatiha Sangar-Mavouna for cloning the human version of the ROCK2 constructs published by Amano et al and Ms U. Schultz for technical assistance with tumour samples processing. We thank the members of the Jaulin lab and Digestive Cancer Unit for discussion. We thank T. Omelchenko and S. Deborde for critical reading of the manuscript. This work was supported by the CNRS/INSERM ATIP-AVENIR programme, the Gustave Roussy foundation (Natixis), the INCA PLBIO and the LNCC comité IDF support to FJ, the French government MESR PhD fellowship and “Fondation pour la recherche medicale” (FDT20160435539) fourth-year PhD fellowship to FL, “Roulons pour le colon” and “Parrainez un chercheur” fund raising to OZ and RL. This work is dedicated to the memory of Alan Hall, an inspiring scientist and mentor. We thank Pr. Xuewu Zhang (University of Texas, USA) for providing us with the FARP1 and FARP2 constructs (He et?al,) which we used to generate lentiviral-based expression vectors, Pr. Yoshimi Takai (Kobe University, Japan) for the pEGFP-FARP2, Fatiha Sangar-Mavouna for cloning the human version of the ROCK2 constructs published by Amano et?al and Ms U. Schultz for technical assistance with tumour samples processing. We thank the members of the Jaulin lab and Digestive Cancer Unit for discussion. We thank T. Omelchenko and S. Deborde for critical reading of the manuscript. This work was supported by the CNRS/INSERM ATIP-AVENIR programme, the Gustave Roussy foundation (Natixis), the INCA PLBIO and the LNCC comit? IDF support to FJ, the French government MESR PhD fellowship and ?Fondation pour la recherche medicale? (FDT20160435539) fourth-year PhD fellowship to FL, ?Roulons pour le colon? and ?Parrainez un chercheur? fund raising to OZ and RL.
| Funders | Funder number |
|---|---|
| Fatiha Sangar-Mavouna | |
| Jaulin lab and Digestive Cancer Unit | |
| Kobe University | |
| Institut national de la santé et de la recherche médicale | |
| Fondation pour la Recherche Médicale | FDT20160435539 |
| Centre National de la Recherche Scientifique | |
| Institut National du Cancer | |
| Fondation Gustave Roussy |
Keywords
- GTPases
- collective migration
- colorectal carcinoma
- invasion
- leader cells
