Keys, J. T. | Search bioRxiv

bioRxiv2022

Rear cortex contraction aids in nuclear transit during confined migration by increasing pressure in the cell posterior

As cells migrate through biological tissues, they must frequently squeeze through micron-sized constrictions in the form of interstitial pores between extracellular matrix fibers and/or other cells. Although it is now well recognized that such confined migration is limited by the nucleus, which is the largest and stiffest organelle, it remains incompletely understood how cells apply sufficient force to move their nucleus through small constrictions. Here, we report a mechanism by which contraction of the cell rear cortex pushes the nucleus forward to mediate nuclear transit through constrictions. Laser ablation of the rear cortex reveals that pushing forces behind the nucleus are the result of increased intracellular pressure in the rear compartment of the cell. The pushing forces behind the nucleus depend on accumulation of actomyosin in the rear cortex and require Rho-kinase (ROCK) activity. Collectively, our results suggest a mechanism by which cells generate elevated, intracellular pressure in the posterior compartment to facilitate nuclear transit through 3D constrictions. This mechanism may supplement or even substitute for other mechanisms supporting nuclear transit, ensuring robust cell migrations in confined 3D environments.

cell biology↗

bioRxiv2020

Chemical-Genetic Interrogation of Nuclear Size Control Reveals Cancer-Specific Effects on Cell Migration and Invasion

Lower survival rates for many cancer types correlate with increases or decreases in nuclear size/scaling in a tumor-type/tissue-specific manner. Postulating that nuclear size changes confer a fitness advantage on tumor cells, we screened for FDA/EMA-approved compounds that reverse tumor nuclear size changes in cell lines from three such tumor types: prostate adenocarcinoma, colonic adenocarcinoma, and small-cell squamous lung cancer. We found distinct, largely non-overlapping sets of compounds that either rectify or exacerbate nuclear size changes for each tumor type. Nuclear size phenotypes across cell lines clustered particular classes of compounds including serotonin uptake inhibitors, cyclo-oxygenase inhibitors, beta-adrenergic receptor agonists, monoamine oxidase inhibitors, and Na+/K+ ATPase inhibitors. Nearly all compounds selected for further investigation inhibited cell migration and/or invasion, suggesting that targeting nuclear size control pathways in chemotherapy regimens could improve patient survival.

cancer biology↗