3.2. The roles of lamellipodia and filopodia in immune cells’
activity during malignancy
Lamellipodia and filopodia on macrophages and T cells play crucial roles
in malignancy, largely due to their involvement in cell movement,
environmental sensing, and immune responses. Macrophage filopodia assist
in the phagocytic uptake of particles, aiding in pathogen clearance.
They capture pathogens by various mechanisms, including surfing along
the filopodial shaft towards the cell body and sweeping actions. These
mechanisms are crucial for the phagocytic uptake of particles and, by
extension, plays a significant role in tumor immunity where phagocytosis
of cancer cells is involved [33]. In T cells, lamellipodia and
filopodia play a crucial role in crossing endothelial barriers, a
process vital during immune surveillance and inflammation. Rho GTPases,
which regulate cytoskeletal dynamics, are essential for T-cell
polarization and migration [34]. A study by Doh, Song, and Kwon
(2013) found that T cells utilize lamellipodia to sense topography of
endothelial cell layers and filopodia to sense nuclei of endothelial
cells, crucial for optimal intraluminal path finding during
transendothelial migration [35]. Ward (2009) described
shear-facilitated chemokine-induced adhesive filopodia on crawling T
lymphocytes that scan the endothelial surface for potential sites of
transendothelial migration, indicating a novel mode of lymphocyte
locomotion over endothelial cells before extravasation [36]. Shulman
et al. (2009) found that endothelial-presented chemokines triggered
high-affinity lymphocyte function-associated antigen 1 (LFA-1) and
adhesive filopodia underneath crawling lymphocytes, which were critical
for lymphocyte crawling and probing for transendothelial migration sites
[37].