Epithelial-mesenchymal transition in high grade serous ovarian cancer cells

Introduction. Epithelial-mesenchymal transition (EMT) is the major driver of invasion and metastasis of cancer cells. The hallmarks of EMT are disruption of stable cell-cell adhesion and acquisition of a migratory phenotype by epithelial cells. Aim. To study of migratory activity and intracellular distribution of cell-cell adhesion proteins, actin cytoskeleton and vimentin intermediate filaments in primary cultures of high grade serous ovarian cancer obtained from clinical samples using correlative live cell imaging/immunofluorescence microscopy. Materials and methods. Using correlative live cell imaging/immunofluorescence microscopy, we studied cell migration and intracellular distribution of cell-cell adhesion proteins, actin cytoskeleton structures and vimentin intermediate filaments. Results. In primary cultures of high grade serous ovarian cancer many traits of incomplete EMT were observed, namely: dramatic remodeling of the actin cytoskeleton, reorganization of adherens junctions with retention of E-cadherin expression in the majority of samples, expression of mesenchymal markers such as vimentin and N-cadherin, and enhanced migratory activity. Different cell populations exhibited heterogeneous levels of EMT markers, for example, a prominent vimentin intermediate filament network was detected in actively migrating cancer cells. Conclusion. High grade serous ovarian cancer cells with enhanced migration potential undergo incomplete EMT which is the optimal choice for promoting invasion and metastasis.