Active K‐RAS induces the coherent rotation of epithelial cells: A model for collective cell invasion in vitro

Abstract

At the invasive front of adenocarcinomas, single cells and multicellular structures exist; the latter include glands and cell clusters, such as tumor buddings and poorly differentiated clusters. Recent reports suggest the importance of collective cell migration in metastasis; however, it is technically difficult to observe the movement of multicellular structures in vivo. We utilized MDCK cells as a model for epithelial cells and established a method to quantify their motility in 3D structures in vitro. A single MDCK cell grows as a cell cluster in the gel and later proliferates and forms a cyst. Active K‐RAS expression induced rotation of both the cell clusters and the cysts. The rotation speed of cell clusters was 4 times higher than that of cysts. The screening of inhibitors for their effects on cell clusters and cysts revealed that cyclin B1 and β‐catenin were the key molecules for their rotation, respectively. Regulators for cyst rotation, such as vorinostat and β‐catenin, were not effective for inducing cell cluster rotation. These results indicate that the signaling pathways of cell dynamics are different between cell clusters and cysts. As cell clusters are related to lymph node involvement and the prognosis of various carcinomas, our in vitro quantitative system may be useful for the screening of drugs to prevent lymphatic invasion.

ERK Activity Imaging During Migration of Living Cells In Vitro and In Vivo

“…We recently found that K-RAS expression accelerates the rotation of cell clusters or cysts (Figure 2A) [31]. The major downstream pathways from the active K-RAS are RAF-MEK-ERK, RALGEF, and PI3K-AKT.…”

“…It is therefore likely that the endogenous activation of ERK is regulated in a different way in the K-RAS active cancer cells. We found that the active K-RAS expression induced coherent rotation of cysts, with lower velocity compared to clusters [31]. Treatment with vorinostat, an HDAC inhibitor, or active β-catenin expression enhanced the rotation of cysts, but not clusters, indicating that the molecular mechanisms for rotation differ between these two structures (Figure 2A).…”

Poorly differentiated clusters in colorectal cancer: a current review and implications for future practice

“…[44][45][46] Several other studies have begun to address biological aspects of PDC but data is currently insufficient for any firm conclusions to be drawn. [47][48][49][50][51][52] More recently, PDC grade has been significantly associated with another novel invasive front prognostic marker, desmoplastic stroma type (DST) (Figure 8). 4,9 Ueno et al postulated that both PDC and DST are morphological manifestations of EMT at the invasive front, and therefore sought to combine these features in a unified grading system, designated grade EMT .…”

Long-term live imaging of epithelial organoids and corresponding multiscale analysis reveal high heterogeneity and identify core regulatory principles

“…We were able to show that organoids differ in their overall rotation speed and rotation direction, in their cell motion depending on their position within the organoid and that not all organoids show rotational behaviour. In general, rotation in organoids is poorly described directly, however, dynamic processes are already investigated in other 3D cell culture systems (Ferrari et al, 2008; Hirata et al, 2018; Marmaras et al, 2010; Tanner et al, 2012). Sebrell et al related the rotation of gastric epithelial organoids to the passage number and patient/donor history (Sebrell et al, 2018).…”