3D matrix adhesion composition facilitates nuclear force coupling to drive invasive cell migration

Abstract

Cell invasion and metastasis is a multi-step process, initialised through the acquisition of a migratory phenotype and the ability to move through differing and complex 3D extracellular environments. In this study we set out to identify the parameters required for invasive cell migration in 3D environments. Cells interact with the extracellular matrix via transmembranespanning integrin adhesion complexes, which are well characterised in cells plated on 2D surfaces, yet much less is known about them in cells embedded in 3D matrices. We establish a technique to determine the composition of cell matrix adhesion complexes of invasive breast cancer cells in 3D matrices and on 2D surfaces and we identify an interaction complex enriched in 3D adhesive sites required for 3D invasive migration. Depletion of β-PIX-Myosin18A (Myo18A) abolishes cancer cell invasion, without negatively affecting matrix degradation, Rho GTPase signalling, or protrusion formation in collagen matrices. Instead, in a mechanism only seen in cells moving through 3D matrix, β-PIX and Myo18A drive the polarised recruitment of non-muscle Myosin 2A (NM2A) to the tips of protrusions. This recruitment of NM2A is required for the creation of an NM2A-NM2B isoform gradient, which ranges from the protrusion to the nucleus. We observe a requirement for active force transmission to the nucleus during invasive migration that is needed to pull the nucleus forward. We postulate that the establishment of the NM2A-NM2B actomyosin gradient facilitates the coupling of cell-matrix interactions at the protrusive cell front with nuclear movement, enabling effective invasive migration and front-rear cell polarity.

Emerging concepts of myosin 18A isoform mechanobiology in organismal and immune system physiology, development, and function

“…65 In this context, Newman et al reported that MYO18Aα operates at three-dimensional level to convey integrin-associated cell-matrix interactions with nuclear movement through MYH9 across the cell. 23 Work by Yu and colleagues identified the interaction of MYO18Aɑ with the p21-activated kinase 2 (PAK2) via binding of the carboxy-terminal extension of MYO18Aɑ with the PAK-interacting exchange factor βPIX. 66 PAK2 is a regulator of actin organization and cell migration, which forms a complex with βPIX and the G-protein-coupled receptor kinase interactor 1 (GIT1), both of which localize to focal adhesions and mediate lamellipodia and membrane ruffle formation.…”

“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] MYO18Aα connects integrin-associated cell-matrix interactions with nuclear movement, a function that may take a leading role in malignant cell migration in three-dimensional matrix. 23 The role of MYO18Aα as a driver of cancer progression or suppression, however, appears to be tissue or cell typedependent that may manifest at different stages of malignancy when physiologic conditions are compromised. [24][25][26][27] MYO18A isoforms have been localized to the leading…”

Unravelling cell migration: defining movement from the cell surface

“…Otherwise, the adhesion complex cannot maintain high force transmission because of an unstructured or fluidized, softened cytoskeleton [ 150 ]. Also, preliminary reports from Newman and colleagues [ 151 ] showed that IACs in protrusions enable actomyosin-mediated force transmission to the nucleus. The ECM is paramount for this mechanism because substrate rigidity directly controls when contractile forces are optimally transmitted.…”

“…Still, studies must be translated to 3D in vivo scenarios because of the stark differences between these two systems regarding their biochemical and biophysical properties [ 171 ]. For instance, we still do not know much about the composition, regulation, and role of IACs in 3D domains [ 122 ,, 151 ]. New protocols are required to increase our knowledge of the mechanisms of cell–matrix interactions in these more realistic environments [ 33 , 236 ].…”

“…For instance, how does the LINC complex sense and transduce forces? Preliminary reports from Newman and colleagues [ 151 ] have recently shed some light on this issue. In particular, the authors showed nuclear force transduction between IACs and the LINC complex in invasive migrating cells within 3D environments.…”