Abstract
The maintenance of precise cell volume is critical for cell survival. Changes in extracellular osmolarity affect cell volume and may impact various cellular processes such as mitosis, mitochondrial functions, DNA repair as well as cell migration and proliferation. Much of what we know about the mechanisms of cell osmoregulation comes from in vitro two-dimensional (2D) assays that are less physiologically relevant than three-dimensional (3D) in vitro or in vivo settings. Here, we developed a microfluidic model to study the impact of hyper-osmotic stress on the migration, proliferation and ion channel/transporter expression changes of three metastatic cell lines (MDA-MB-231, A549, T24) in 2D versus 3D environments. We observed a global decrease in cell migration and proliferation upon hyper-osmotic stress treatment, with similar responses between 2D and 3D conditions. Specific ion channels/aquaporins are over-expressed in metastatic cells and play a central role during osmo-regulation. Therefore, the effects of hyper-osmotic stress on two transporters, aquaporin 5 (AQP5) and the transient receptor potential cation channel (TRPV4), was investigated. While hyper-osmotic stress had no major impact on the transporters of cells cultured in 2D, cells embedded in collagen gel (3D) decreased their AQP5 expression and exhibited a reduction in intra-cellular translocation of TRPV4. Furthermore, cell dispersion from T24 aggregates embedded in 3D collagen gel decreased with higher levels of hyper-osmotic stress. In conclusion, this study provides evidence on the impact of hyper-osmotic stress on various aspects of metastatic cell progression and highlights the importance of having a 3D cell culture platform in investigating molecular players involved in cancer cell migration.
Highlights
The first step of the metastatic cascade is the dissociation of cancer cells from the tumor and their migration through the stroma toward the blood stream[1,2]
This study further investigates the expression of aquaporin 5 (AQP5) and the transient receptor potential cation channel (TRPV4) as these are highly involved in osmo-regulation
Despite cancer cells capacities to cope with volume changes, we showed that hyper-osmotic stress impacts cancer cell migration and proliferation (Fig. 1B–G) in 3D and 2D conditions and for the three metastatic cell lines tested, with cell proliferation slightly more affected in 2D than in 3D
Summary
The first step of the metastatic cascade is the dissociation of cancer cells from the tumor and their migration through the stroma toward the blood stream[1,2]. Pathak et al showed that the migration speed of a confined cell increases with the stiffness of the environment[11] Other parameters such as mechanical compression can critically impact cancer cell migration and proliferation, and their growth in the form of tumor spheroids[12,13,14]. One possible reason for the differences observed is the implication of specific ion pumps and aquaporins These transporters which play crucial roles in osmoregulation – are associated with metastatic status[21,22] and are involved in cancer cell migration through confined spaces[23]. Cells are surrounded by the extracellular matrix which is composed of fibrillar collagen forming pores of various sizes that affect signal transduction, gene regulation, cellular behavior as well as cell morphology Those modifications are necessary for the cells to adapt to different topology and rigidity to successfully transmigrate. Because 2D models lack the physical constraints and spatial organization of the cell in its microenvironment, traditional monolayer cultures are less physiologically relevant than 3D matrix to study biological mechanisms such as tumor cell migration or response to various stimuli[24,25]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
