Myosin light chain kinase mediates transcellular intravasation of breast cancer cells through the underlying endothelial cells: a three-dimensional FRET study.
The transient and localized signaling events between invasive breast cancer cells and the underlying endothelial cells have remained poorly characterized. We report a novel approach integrating vascular engineering with three-dimensional time-lapse fluorescence resonance energy transfer (FRET) imaging to dissect how endothelial myosin light chain kinase (MLCK) is modulated during tumor intravasation. We show that tumor transendothelial migration occurs via both paracellular (i.e. through cell-cell junctions) and transcellular (i.e. through individual endothelial cells) routes. Endothelial MLCK is activated at the invasion site, leading to regional diphosphorylation of myosin-II regulatory light chain (RLC) and myosin contraction. Blocking endothelial RLC diphosphorylation blunts tumor transcellular, but not paracellular, invasion. Our results implicate an important role for endothelial myosin-II function in tumor intravasation.
Khuon
Satya
S
Cell Imaging Facility, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Liang
Luke
L
Dettman
Robert W
RW
Sporn
Peter H S
PH
Wysolmerski
Robert B
RB
Chew
Teng-Leong
TL
D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D002417:Cattle; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018613:Microscopy, Confocal; D009219:Myosin-Light-Chain Kinase / Q000235:genetics / Q000378:metabolism*; D009361:Neoplasm Invasiveness / Q000473:pathology*; D010766:Phosphorylation
D009219:Myosin-Light-Chain Kinase