Tumor-endothelium cross talk blocks recruitment of neutrophils to endothelial cells: a novel mechanism of endothelial cell anergy.
Tumor cells have evolved effective strategies to escape the host immune response. The objective of this study was to determine whether tumor cells can condition endothelial cells in a specific manner to prevent subsequent adhesion of polymorphonuclear neutrophils (PMNs) and/or peripheral blood lymphocytes (PBLs). Human umbilical vein endothelial cells (HUVECs) and UKF-NB-4 neuroblastoma tumor cells were established in coculture on opposite sides of porous transwell filters. After 24 hours with and without HUVEC conditioning, PMNs or PBLs were added to the HUVEC monolayer. Adhesion to conditioned HUVEC versus adhesion to nonconditioned HUVEC was compared. Effects on endothelial CD44v4, CD44v5, CD44v7, intercellular adhesion molecule 1 (ICAM-1), E-selectin, and vascular cell adhesion molecule 1 (VCAM-1) adhesion receptor expression were analyzed by flow cytometry, intracellular signaling proteins of the mitogen-activated protein kinase pathway and protein kinase C (PKC) subtypes quantified by Western blot analysis. Endothelial conditioning led to a distinct reduction in PMN but not in PBL adhesion to HUVEC. CD44 was significantly reduced, whereas ICAM-1, E-selectin, and VCAM-1 were not altered during HUVEC conditioning. Antibody blockade against CD44v4, CD44v5, and CD44v7 inhibited PMN but not PBL binding. The observed effects were caused by direct tumor cell-HUVEC contact because addition of isolated tumor cell membrane fragments but not of soluble cell culture supernatant to HUVEC induced the CD44 receptor loss. PKCalpha activity was strongly enhanced in conditioned HUVEC. Blocking PKC prevented the reduction in PMN binding, indicating that this protein is involved in PMN adhesion regulation. A novel tumor escape strategy is presented here. Cell contact-dependent adhesion of tumor cells to the vascular wall promotes down-regulation of endothelial CD44 receptor expression, impairing an effective neutrophil attack.
Zentrum der Chirurgie, Klinik für Urologie und Kinderurologie, Johann Wolfgang Goethe-Universität, 60596 Frankfurt am Main, Germany.
Roman A
RA
Blaheta
Maciej
M
Powerski
Lukasz
L
Hudak
Eva
E
Juengel
Dietger
D
Jonas
Andreas
A
von Knethen
Hans Willhelm
HW
Doerr
Jindrich
J
Cinatl
D015153:Blotting, Western; D002448:Cell Adhesion; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D018920:Coculture Techniques; D019040:E-Selectin / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000166:cytology* / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology; D009504:Neutrophils / Q000166:cytology* / Q000378:metabolism; D051571:Protein Kinase C-alpha / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
C497483:CD44 protein, human; C113800:CD44v5 antigen; D019040:E-Selectin; D018960:Hyaluronan Receptors; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D051571:Protein Kinase C-alpha