Extracellular fluid viscosity enhances cell migration and cancer dissemination

Abstract

Cells respond to physical stimuli, such as stiffness1, fluid shear stress2 and hydraulic pressure3,4. Extracellular fluid viscosity is a key physical cue that varies under physiological and pathological conditions, such as cancer5. However, its influence on cancer biology and the mechanism by which cells sense and respond to changes in viscosity are unknown. Here we demonstrate that elevated viscosity counterintuitively increases the motility of various cell types on two-dimensional surfaces and in confinement, and increases cell dissemination from three-dimensional tumour spheroids. Increased mechanical loading imposed by elevated viscosity induces an actin-related protein 2/3 (ARP2/3)-complex-dependent dense actin network, which enhances Na+/H+ exchanger 1 (NHE1) polarization through its actin-binding partner ezrin. NHE1 promotes cell swelling and increased membrane tension, which, in turn, activates transient receptor potential cation vanilloid 4 (TRPV4) and mediates calcium influx, leading to increased RHOA-dependent cell contractility. The coordinated action of actin remodelling/dynamics, NHE1-mediated swelling and RHOA-based contractility facilitates enhanced motility at elevated viscosities. Breast cancer cells pre-exposed to elevated viscosity acquire TRPV4-dependent mechanical memory through transcriptional control of the Hippo pathway, leading to increased migration in zebrafish, extravasation in chick embryos and lung colonization in mice. Cumulatively, extracellular viscosity is a physical cue that regulates both short- and long-term cellular processes with pathophysiological relevance to cancer biology.

Crosstalk between regulatory elements in the disordered TRPV4 N-terminus modulates lipid-dependent channel activity

“…The peripheral ankyrin repeats 1, 2 and 6 underwent faster exchange (HDX at 10 3 s). The combined observations from HDX-MS and SAXS demonstrate that the ARD, although globally compact, experiences complex conformational dynamics, i.e., slower motions in the ARD core and faster dynamics within the ARD loops and peripheral ankyrin repeats in agreement with the extensive line broadening observed in the [ 1 H, 15 N]-NMR spectrum of the NTD (Fig. S2b).…”

“…Mutation of the patch did not alter the lipid interaction pattern with the central IDR and PIP2-binding site per se as gauged by 1 H, 15 N-NMR spectroscopy and MD simulations (Fig. 8c, Fig.…”

“…The avian proteins were chosen due to their increased stability compared to their human counterparts 27 . Analytical size-exclusion chromatography (SEC) and SEC-MALS (SEC multi-angle light scattering) showed that these constructs are monomeric, while circular dichroism (CD) spectroscopy and the narrow chemical shift dispersion of the [ 1 H, 15 N]-NMR (nuclear magnetic resonance) spectra of the 15 N-labeled TRPV4 IDR in isolation or in the context of the NTD confirmed its high amount of disorder 5 (Fig. 1c-e; Fig.…”

“…S3). Interdomain contacts between the IDR and ARD were also apparent from the loss of IDR signal intensities in the 1 H, 15 N-NMR spectra of the isolated 15 N-labeled IDR compared to the NTD (Fig. S2b, c), e.g.…”

“…TRPV4 also garnered attention due to the large number of diseasecausing mutations with distinct tissue-specific phenotypes primarily affecting the nervous and skeletal systems [9][10][11][12][13] . Among others, roles in cancer as well as viral and bacterial infections have also been described [14][15][16] .…”