Nuclear export inhibition jumbles epithelial-mesenchymal states and gives rise to migratory disorder in healthy epithelia

Abstract

Epithelial-mesenchymal (E-M) phenotypes govern collective cellular behaviors to facilitate diverse tissue functions, including embryogenesis, wound healing, and cancer invasion. Cellular E-M state is regulated by dynamic nucleocytoplasmic transport of corresponding E-M factors; yet, it remains unknown how concurrently trapping these factors affects epithelia at the macroscale. To explore this question, we performed nuclear export inhibition (NEI) via Leptomycin B treatment, which biases nuclear localization of CRM1- associated E-M factors. We examined changes in collective cell migration across a range of substrate stiffnesses. Our results show that NEI fosters an atypical E-M state wherein cells concurrently strengthen intercellular adhesions and develop mechanoactive characteristics. Following NEI, soft substrates elevate collective migration for up to 24 h, while stiffer substrates reduce migration at all timepoints. We demonstrate that excluding Yes-associated protein 1 from NEI shifts affected cells toward an epithelial phenotype. Meanwhile, removing -catenin maintains NEIs intercellular adhesion strengthening and mechanoactivation capabilities, but prevents mechanoactive characteristics from reaching collective behavior. Overall, our results show that NEI disrupts epithelial migration through competition between intercellular adhesions, mechanoactivation, and cell-cell coordination. Ultimately, these findings of mechanoactive NEI outcomes for healthy cells could warrant additional investigation in the context of NEI-centered cancer therapies.