Cell intrinsic and environmental factors influencing human bronchial epithelial cell migration

BACKGROUND Preinvasive lung cancer cells migrate across histologically normal epithelium before seeding at new sites and progressing to invasive disease. To develop novel therapeutic targets to treat lung cancer, we must understand the mechanisms responsible for this migration. We therefore aimed to understand the cell-intrinsic and environmental mechanisms behind human bronchial epithelial cell (HBEC) migration. METHODS We developed a novel ex vivo high-content bioassay to monitor the migration of HBECs in a confluent epithelium. Cells were expanded from endobronchial brush or biopsy samples and grown to confluence. 2% of cells were fluorescently labelled and individual cells were tracked using the ImageXpress Micro XLS for 48 hours. Migration was measured after exposure to the Rho-associated kinase inhibitor Y27632 or the Rac1 GTPase inhibitor EHT1864, or after attachment to a physiological lung extracellular matrix produced by macromolecular crowding of human lung fibroblasts. RESULTS Y27632 and EHT1864 significantly reduced HBEC migration. Mean distance migrated was 926.5 μm in control conditions, 560.2 μm in 5 μM Y27632 ( P P P =0.0002 and P =0.0799, respectively). CONCLUSION Cell-intrinsic Rho-GTPase activity regulates HBEC migration in a confluent epithelium. Extracellular matrix composition effects migration but the exact role of matrix density is unclear. Inhibition of Rho-GTPase activity may hold promise as a therapy to limit preinvasive cell migration and progression to invasive disease.