Journal: eLife
Article Title: Cell crowding activates pro-invasive mechanotransduction pathway in high-grade DCIS via TRPV4 inhibition and cell volume reduction
doi: 10.7554/eLife.100490
Figure Lengend Snippet: ( A ) In MCF10CA1a cells, plasma membrane relocation of TRPV4 was induced by a 15 min treatment with 2% PEG 300 (74.4 mOsm/kg) or by overconfluence (OC) conditions. IF images show a largely intracellular distribution of TRPV4 (red) in normal density (ND) control cells, whereas cells treated with PEG 300 or subjected to OC exhibit a significant increase in plasma membrane-associated TRPV4. Nuclei are stained with DAPI (blue). Scale bars in all panels of this figure represent 10 μm. ( B ) Line analysis quantifying plasma membrane-associated TRPV4 (%) reveals significant increases following a 1 hr treatment with GSK219 (1 nM), a 15 min exposure to 74.4 mOsm/kg PEG 300, or under OC conditions in MCF10CA1a cells. In contrast, no significant increase in plasma membrane TRPV4 is observed with GSK101 treatment. ( C ) In MCF10CA1a cells, cell movement diffusivity ( D ) increased following GSK219 or PEG 300 treatments, whereas it decreased with GSK101. Conversely, movement directionality ( v ) increased significantly with GSK101 (0.2 pM) but remained unchanged with GSK219 or PEG treatments. ( D-O ) No plasma membrane relocation of TRPV4 was observed in response to inhibition by GSK219, hyperosmotic stress induced by PEG 300, or cell crowding (OC) in MCF10AT1 ( D, E, F ), MDA-MB-231 ( G, H, I ), ETCC-006 ( J, K, L ), and ETCC-010 ( M, N, O ) cells. Similarly, GSK219 or PEG 300 did not increase single-cell motility in these cells. This is demonstrated by IF images (TRPV4: red; DAPI: blue) ( D, G, J, M ), line analysis results for plasma membrane-associated TRPV4 ( E, H, K, N ), and single-cell motility analyses for diffusivity ( D ) and directionality ( v ) ( F, I, L, O ). Notably, none of these cell lines showed motility changes in response to PEG 300 treatment. However, responses to TRPV4 activation (GSK101) and inhibition (GSK219) varied across cell types, suggesting distinct roles of TRPV4 in their cancer biology. In MCF10AT1 cells ( F ), GSK219 significantly reduced diffusivity ( D ), while no other treatment affected D or v . In MDA-MB-231 cells ( I ), neither D nor v was altered by any treatment, indicating that TRPV4 has an insignificant role in their motility. Both ETCC-006 and ETCC-010 cells exhibited increased diffusivity with GSK101; however, GSK219 also increased diffusivity in ETCC-006 cells ( L ), while having no effect on ETCC-010 cells ( O ). Directionality ( v ) increased with GSK101 in ETCC-006 cells ( L ), whereas ETCC-010 cells showed no change in v across all conditions ( O ). The number of line analyses for plasma membrane-associated TRPV4 under ND control, ND +0.2 pM GSK101, ND +1 nM GSK219, ND +2% PEG 300, and OC conditions (technical replicates merged from three independent experimental repeats) were: MCF10CA1a (B): 11, 6, 8, 12, 10; MCF10AT1 ( E ): 13, 9, 8, 9, 19; MDA-MB-231 ( H ): 13, 9, 8, 9, 19; ETCC-006 ( K ): 12, 10, 10, 5, 10; and ETCC-010 (N): 5, 5, 7, 5, 6. The number of single-cell motility analyses under ND control, ND +0.2 pM GSK101, ND +1 nM GSK219, and ND +2% PEG 300 conditions were: MCF10CA1a ( C ): 100, 100, 100, 100; MCF10AT1 ( F ): 130, 161, 582, 183; MDA-MB-231 ( I ): 57, 6, 21, 442; ETCC-006 ( L ): 65, 66, 24, 100; and ETCC-010 (O): 317, 1136, 43, 71. ( P ) Plasma membrane association of TRPV4 (% PM TRPV4) scaled positively with cell diffusivity ( D ) over a broader range in MCF10DCIS.com cells compared to MCF10CA1a cells, consistent with the higher cell volume plasticity observed in MCF10DCIS.com cells. This finding suggests that both cell types engage a pro-invasive mechanotransduction pathway. ( Q ) In contrast, this scaling relationship is absent in MCF10AT1, MDA-MB-231, ETCC-006, and ETCC-010 cells, indicating a lack of the mechanotransduction response. ( R ) The presence of this pathway in MCF10CA1a and MCF10DCIS.com cells is further supported by the observed > twofold increase in TRPV4 plasma membrane association (x-axis; PM TRPV4_peg/PM TRPV4_ctrl) and > onefold increase in diffusivity (y-axis; Dpeg/Dctrl) following PEG-300 treatment. ( S ) The cell volume reduction-driven mechanotransduction pathway is further demonstrated by plotting PEG-300-induced changes in TRPV4 plasma membrane association (x-axis; PM TRPV4_peg/PM TRPV4_ctrl) against the diffusivity ratio with GSK219 versus GSK101 (y-axis), where both cell types show a significantly greater than twofold increase, highlighting the activation of this pathway in MCF10DCIS.com and MCF10CA1a cells.****p<0.0001, ***p<0.001, **p<0.01, *p<0.05, ns: p>0.05. Figure 6—source data 1. Original data corresponding to panel B. Figure 6—source data 2. Original data corresponding to panel C. Figure 6—source data 3. Original data corresponding to panel E. Figure 6—source data 4. Original data corresponding to panel F. Figure 6—source data 5. Original data corresponding to panel H. Figure 6—source data 6. Original data corresponding to panel I. Figure 6—source data 7. Original data corresponding to panel K. Figure 6—source data 8. Original data corresponding to panel L. Figure 6—source data 9. Original data corresponding to panel N. Figure 6—source data 10. Original data corresponding to panel O. Figure 6—source data 11. Original data corresponding to panels P and Q. Figure 6—source data 12. Original data corresponding to panels R and S.
Article Snippet: Cells were seeded in a LabTek II 8-well Chambered Coverglass dish (Thermo Fisher 155409) at a density of 10,000 cells per well and allowed to adhere and grow for 2 d. Afterward, the cells were incubated on ice for 1 hr with 1:300 Anti-TRPV4 (extracellular) rabbit primary antibody (Alomone ACC-124) in either complete media or 74 mOsm/Kg PEG 300 in complete media.
Techniques: Membrane, Control, Staining, Inhibition, Activation Assay