(690e) Novel 2.5D Cell Culture Platforms to Investigate the Role of Stiffness Gradients on Cell Migration

Although it is now well understood that migrating cells in vivo often encounter spatial variations in extracellular matrix stiffness, current research investigating cell migration focus on the use of culture platforms with static material parameters. Therefore, we developed a novel 2.5D culture platform where the cells are placed at the interface of stiff tissue culture plastic and a soft hydrogel matrix, to mimic the transitions in microenvironmental stiffness experienced by cells in vivo. Alginate was chosen as the hydrogel matrix because it facilitated independent investigation of both matrix stiffness gradients and cell-matrix adhesions on migration. Under these conditions, we observed cell migration from the underlying stiff substrate into alginate. Observation of migration into alginate in the presence of integrin inhibition as well as qualitative microscopic analyses suggested an adhesion-independent cell migration mode. Additionally, the observed migration was dependent on alginate matrix stiffness as well as the RhoA-ROCK-myosin-II pathway; inhibitors specifically targeting ROCK and myosin-II arrested cell migration. These studies will potentially facilitate the development of relevant in vitro platforms to discover therapeutic strategies against tumor cell motility and invasion.