Nrf2 regulates collective cancer migration by modulating the hybrid epithelial/mesenchymal phenotype

Hybrid epithelial/mesenchymal cells (E/M) are key players in aggressive cancer metastasis. A challenge is to understand how these cells, which are mostly non-existent in healthy tissue, become stable phenotypes participating collective cancer migration. The transcription factor Nrf2, which is associated with tumor progression and resistance to therapy, appears to be central to this process. Here, using a combined experimental-computational approach, we show that Nrf2 functions as a phenotypic stability factor for hybrid E/M cells by inhibiting a complete epithelial-mesenchymal transition (EMT) during collective cancer migration. We demonstrate that Nrf2 and EMT signaling are spatially coordinated near the migrating front. Computational analysis of Nrf2-EMT-Notch network and experimental modulation of Nrf2 by pharmacological treatment and CRISPR/Cas9 gene editing reveal that Nrf2 stabilizes a hybrid E/M phenotype maximally observed in the interior region immediately behind the leading edge. We further demonstrate that the Nrf2-EMT-Notch network enhances Dll4 and Jagged1 expression near the leading edge, which correlates with the formation of protruding tips and leader cells. Together, Nrf2 acts as a phenotypic stability factor in restricting complete EMT and coordinating collective cancer migration.