LIM kinases are required for invasive path generation by tumor and tumor-associated stromal cells.
LIM kinases 1 and 2 (LIMK1/2) are centrally positioned regulators of actin cytoskeleton dynamics. Using siRNA-mediated knockdown or a novel small molecule inhibitor, we show LIMK is required for path generation by leading tumor cells and nontumor stromal cells during collective tumor cell invasion. LIMK inhibition lowers cofilin phosphorylation, F-actin levels, serum response factor transcriptional activity and collagen contraction, and reduces invasion in three-dimensional invasion assays. Although motility was unaffected, LIMK inhibition impairs matrix protein degradation and invadopodia formation associated with significantly faster recovery times in FRAP assays indicative of reduced F-actin stability. When LIMK is knocked down in MDA-MB-231 cells, they lose the ability to lead strands of collectively invading cells. Similarly, when LIMK activity is blocked in cancer-associated fibroblasts, they are unable to lead the collective invasion of squamous carcinoma cells in an organotypic skin model. These results show that LIMK is required for matrix remodeling activities for path generation by leading cells in collective invasion.
Scott
Rebecca W
RW
The Beatson Institute for Cancer Research, Garscube Estate, Glasgow G61 1BD, Scotland, UK.
Hooper
Steven
S
Crighton
Diane
D
Li
Ang
A
König
Ireen
I
Munro
June
J
Trivier
Elisabeth
E
Wickman
Grant
G
Morin
Pierre
P
Croft
Daniel R
DR
Dawson
John
J
Machesky
Laura
L
Anderson
Kurt I
KI
Sahai
Erik A
EA
Olson
Michael F
MF
D051339:Actin Depolymerizing Factors / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D045744:Cell Line, Tumor; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D054461:Lim Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D055550:Protein Stability; D034622:RNA Interference; D017154:Stromal Cells / Q000201:enzymology*
D051339:Actin Depolymerizing Factors; D000199:Actins; D054461:Lim Kinases