Reversibility of Nuclear and 3D Genomic Changes in Non-Cancerous Fibroblasts After Constricted Migration
Metastatic cancer cells and healthy fibroblasts must traverse constrictive spaces to reach secondary sites. After passing through multiple constrictions, cancer cells often experience stable changes to their nucleus morphology, 3D genome structure, and migratory phenotype. Here, we investigate whether fibroblasts (BJ-5ta), which are non-cancerous and have an inherent ability to migrate to fulfill roles in wound repair, likewise experience nuclear and 3D genomic changes with constricted migration. We find that BJ-5ta cells do not get progressively better at migrating with sequential attempts but do experience nuclear deformations and 3D genome alterations at the compartment level after constricted migration. Transient compartment shifts spatially rearranged genes associated with preparation for and response to migration. Unlike the stable changes associated with long term phenotype changes in cancer cells, however, the nucleus deformations recovered back to unmigrated levels following proliferation and cell movement. Some compartment changes persist and might influence responses to future stimuli, but most 3D genome changes revert to the unmigrated state after cell proliferation. Our study shows that non-cancerous migratory cells are not more robust against alterations caused by constricted migration but can recover from the ones that do arise more readily than cancer cells. Overall design: The 3D genome structure of BJ-5ta cells was analyzed using chromosome conformation capture (Hi-C) in the following experimental conditions: standard culture conditions, starvation (overnight in serum-free media) followed by 24 hours exposure to Fibroblast Growth Factor, 1 round of constricted migration through 5 micron pores, 1 round of constricted migration followed by 96 hours of recovery, or 5 rounds of constricted migration with recovery time in between each round.