Expression of vimentin intermediate filaments in epithelial cells promotes cell migration and cell matrix interaction in 3D

During a variety of physiological and pathological processes, such as development, wound healing, and tumor progression, epithelial cells collectively invade into their surroundings. Vimentin intermediate filaments (VIFs) are often observed to play a role in the epithelial cells located at the margins of 2D cultures. However, their role in 3D collective cell behavior remains underexplored. Here, we investigate how induced vimentin expression affects 3D multicellular architecture and mechanics in luminal breast cancer cells (MCF-7) that ordinarily express keratin intermediate filaments only. We find that vimentin expression significantly alters 3D cell cluster morphology, inducing protrusions and increasing boundary fluctuations. Furthermore, cells in vimentin-expressing clusters show enhanced, more stochastic migration. In addition, these clusters exert stronger and localized traction forces on the surrounding matrix, indicating increased cell-matrix interactions. Transcriptomic analysis corroborates these biophysical findings, revealing upregulated gene expression for cell migration and matrix adhesion, and downregulated cell-cell adhesion genes. Our results demonstrate that VIFs are critical in modulating 3D multicellular collective morphology and dynamics, promoting invasive-like behavior by enhancing cell migration and cell-matrix interactions. These results provide fundamental insights into understanding tissue morphogenesis and disease progression.