Unjamming overcomes kinetic and proliferation arrest in terminally differentiated cells and promotes collective motility of carcinoma

Abstract

29During wound repair, branching morphogenesis and carcinoma dissemination, cellular 30 rearrangements are fostered by a solid-to-liquid transition known as unjamming. The biomolecular 31 machinery behind unjamming, its physiological and clinical relevance remain, however, a mystery. 32Here, we combine biophysical and biochemical analysis to study unjamming in a variety of epithelial 33 2D and 3D collectives: monolayers, differentiated normal mammary cysts, spheroid models of breast 34 ductal carcinoma in situ (DCIS), and ex vivo slices of orthotopically-implanted DCIS. In all cases, 35 elevation of the small GTPase RAB5A sparks unjamming by promoting non-clathrin-dependent 36 internalization of epidermal growth factor receptor that leads to hyper-activation of endosomally-37 confined ERK1/2 and phosphorylation of the actin nucleator WAVE2. Physically, activation of this 38 pathway causes highly coordinated flocking of the cells, with striking rotational motion in 3D that 39 eventually leads to matrix remodelling and collective invasiveness of otherwise jammed carcinoma. 40The identified endo-ERK1/2 pathway provides an effective switch for unjamming through flocking 41 to promote epithelial tissues morphogenesis and carcinoma invasion and dissemination. 42 43 Introduction 44Collective motility, a widely recognized mode of migration during embryogenesis, wound repair 45 and cancer 1, 2 , refers to the process of many cells migrating as a cohesive group with a high degree of 46 coordination between neighbouring cells. A complex network of biochemical and physical 47 interactions governs cellular and multicellular motility 2-5 . How cellular and supra-cellular 48 biomechanics and biochemical wiring are integrated and impact onto each other remains, however, 49 largely unexplored. 50An emerging framework to interpret these interactions in unifying principles is the notion of cell 51 jamming 6-8 . During tissue growth, cells are rather free to move around, as in a fluid. As density rises, 52 the motion of each cell is constrained by the crowding due to its neighbours. At a critical density, 53 motility ceases and collectives rigidify undergoing a liquid (unjammed)-to-solid (jammed) 54 transition 6-8 , herein referred to as UJT. This transition, which depends on a variety of biophysical 55 parameters such as cell shape variance 9 , intercellular adhesion, cortical tension and single cell 56 motility, is thought to ensure proper development of barrier properties in epithelial tissues, but also 57 to act as a tumour suppressive mechanism 6-8, 10 . The reverse jamming-to-unjamming transition (JUT) 58 might, instead, represent a complementary gateway to epithelial cell migration, enabling tissues to 59 escape the caging imposed by the crowded cellular landscape of mature epithelia 6, 10-12 . Indeed, 60whereas Epithelial-to-Mesenchymal Transition (EMT) has emerged as the overarching mechanism 61 enabling the dissemination of single tumour cells 13, 14 , invasion by epithelial malignancies 62 (carcinomas) frequently involves...

Irradiation Induces Epithelial Cell Unjamming

“…This discovery was rooted firmly in airway biology. Since that time, the concept of cell jamming has diffused widely into the study of other collective cellular systems, and growing evidence from us and others now suggests that the capacity to jam and unjam may be an innate property of many epithelia both in normal development (Atia et al, 2018;Mongera et al, 2018;Spurlin et al, 2019) and in disease (Sadati et al, 2013;Haeger et al, 2014;Park et al, 2015;Bi et al, 2016;Gamboa Castro et al, 2016;Oswald et al, 2017;Atia et al, 2018;Mongera et al, 2018;Palamidessi et al, 2018Palamidessi et al, , 2019Fujii et al, 2019;Spurlin et al, 2019), including asthma (Angelini et al, 2011;Nnetu et al, 2012;Garcia et al, 2015;Park et al, 2015Park et al, , 2016Malinverno et al, 2017;Atia et al, 2018), and cancer (Haeger et al, 2014;Oswald et al, 2017;Palamidessi et al, 2019).…”

Tracking-Free Determination of Single-Cell Displacements and Division Rates in Confluent Monolayers

“…While the transition between the liquid-like and solid-like states of monolayers might be an expected mechanical response of tissues, which are constantly subjected to physical stresses, it has been shown to be governed by a variety of biophysical and biochemical interactions and characterized by peculiar states and emerging collective properties [2,3]. The latter might have strong implications not only for interpreting fundamental biological processes, but also in determining the outcome of diseases, first and foremost in cancer dissemination [4].…”

Distinct Roles of Tumor-Associated Mutations in Collective Cell Migration

“…This signaling pathway has also been implicated in collective dissemination. A recent study of an MCF10A-based model of unjamming in which the small GTPase RAB5A is overexpressed lead to collective invasion in a 3D acini model 17 . This result was mediated by ERK1/2 activation, supporting the idea that pathways downstream of KRas activation may play an important role in collective breast cancer dissemination.…”

“…Plasticity in collective behavior is also seen through the framework of an unjamming transition, which can allow epithelial monolayers to flow collectively without necessitating the activation of EMTtranscription factors or expression of mesenchymal markers 15 . Signatures of unjamming have been observed in both non-tumorigenic MCF10A cells and in MCF10A-based models of breast cancer 16,17 . Unjamming also allows mesenchymal tumor cells to adapt to their surroundings and migrate collectively 18 .…”