ROCK 2 inhibition triggers the collective invasion of colorectal adenocarcinomas

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.

Biophysical properties of intermediate states of EMT outperform both epithelial and mesenchymal states

“…The low-contractile-force phenotype differs from the view that contractile tension increases with cell transformation in cancer (Paszek et al, 2005) and that a higher rigidity of the extracellular environment and a high-contractile-force phenotype favor cell invasiveness (Butcher et al, 2009;Kraning-Rush et al, 2012;Mierke et al, 2011). Rather, our results suggest that the relaxation of contractile forces is associated with cell scattering and migration, as it has been observed in HMECs with super-numerary centrosomes that form invasive structures in 3D cultures (Godinho et al, 2014), in cells at the front of invasive colorectal carcinomas (Libanje et al, 2019) or in metastatic osteosarcoma cells (Holenstein et al, 2019). By contrast, a high-contractile-force phenotype is more likely to promote primary tumor growth, cell survival in circulation, and at a secondary site, cell adhesion, aggregation, and the formation of a metastatic tumor (Rodriguez-Hernandez et al, 2016;Tavares et al, 2017).…”

Rock inhibition promotes NaV1.5 sodium channel-dependent SW620 colon cancer cell invasiveness

“…Our results also appear in apparent contradiction with those obtained by Vishnubhotla and collaborators who reported that ROCK-2 was highly expressed in SW620 colon cancer cells, mainly distributed in invadopodial-like structures and that its knock-down reduced the depth of invasion into a 3D-scaffold of type I collagen 61 . However, our results are in line with those recently reported by Libanje and collaborators who demonstrated that colorectal cancer cells mainly harbour a collective mode of invasion and that ROCK-2 inhibition triggers the initial induction of leader cell formation and induces collective invasion from cysts 62 . Therefore, these apparently contrasting results should probably be studied with regard to the different growing modes and environmental conditions (2D vs 3D, type and stiffness of the extracellular matrix, etc.)…”

Modeling neoplastic disease with spheroids and organoids

“…Cancer organoids have also been used to model metastatic processes, in particular to investigate the different processes of invasion [164,165]. For example, a study conducted on CRC organoids showed that inhibition of rho-associated protein kinase 2 (ROCK2) improved collective invasion in its early stages [166].…”