@article{77d6363cd96e4fd895141d23518a9cc2,
title = "Spatial and temporal dynamics of RhoA activities of single breast tumor cells in a 3D environment revealed by a machine learning-assisted FRET technique",
abstract = "One of the hallmarks of cancer cells is their exceptional ability to migrate within the extracellular matrix (ECM) for gaining access to the circulatory system, a critical step of cancer metastasis. RhoA, a small GTPase, is known to be a key molecular switch that toggles between actomyosin contractility and lamellipodial protrusion during cell migration. Current understanding of RhoA activity in cell migration has been largely derived from studies of cells plated on a two-dimensional (2D) substrate using a FRET biosensor. There has been increasing evidence that cells behave differently in a more physiologically relevant three-dimensional (3D) environment. However, studies of RhoA activities in 3D have been hindered by low signal-to-noise ratio in fluorescence imaging. In this paper, we present a a machine learning-assisted FRET technique to follow the spatiotemporal dynamics of RhoA activities of single breast tumor cells (MDA-MB-231) migrating in a 3D as well as a 2D environment. We found that RhoA activity is more polarized along the long axis of the cell for single cells migrating on 2D fibronectin-coated glass versus those embedded in 3D collagen matrices. In particular, RhoA activities of cells in 2D exhibit a distinct front-to-back and back-to-front movement during migration in contrast to those in 3D. Finally, regardless of dimensionality, RhoA polarization is found to be moderately correlated with cell shape.",
keywords = "Cell migration, ECM, FRET, Motility, Polarization, RhoA",
author = "Cheung, {Brian C.H.} and Louis Hodgson and Segall, {Jeffrey E.} and Mingming Wu",
note = "Funding Information: This work was supported by grants from the National Cancer Institute [Grant No. R01CA221346 (MW and JES)], National Institute of General Medical Sciences [Grant No. R35GM136226 (LH)]; and by the Cornell Center on the Microenvironment & Metastasis [Award No. U54CA143876 from the National Cancer Institute]; the Cornell NanoScale Science and Technology, and the Cornell BRC imaging facility. JES is the Betty and Sheldon Feinberg Senior Faculty Scholar in Cancer Research. LH is a Irma T. Hirschl Career Scientist. We thank Dr. Yu Ling Huang and Young Joon Suh for their assistance in experiments. We also thank Dr. Thorsten Falk from the University of Freiburg for advice on the U-net software package. All Matlab codes and MetaMorph routines are available upon request. Funding Information: This work was supported by grants from the National Cancer Institute [Grant No. R01CA221346 (MW and JES)], National Institute of General Medical Sciences [Grant No. R35GM136226 (LH) ]; and by the Cornell Center on the Microenvironment & Metastasis [Award No. U54CA143876 from the National Cancer Institute ]; the Cornell NanoScale Science and Technology , and the Cornell BRC imaging facility . JES is the Betty and Sheldon Feinberg Senior Faculty Scholar in Cancer Research . LH is a Irma T. Hirschl Career Scientist. We thank Dr. Yu Ling Huang and Young Joon Suh for their assistance in experiments. We also thank Dr. Thorsten Falk from the University of Freiburg for advice on the U-net software package. All Matlab codes and MetaMorph routines are available upon request. Publisher Copyright: {\textcopyright} 2021 Elsevier Inc.",
year = "2022",
month = jan,
day = "15",
doi = "10.1016/j.yexcr.2021.112939",
language = "English (US)",
volume = "410",
journal = "Experimental Cell Research",
issn = "0014-4827",
publisher = "Academic Press Inc.",
number = "2",
}