Vascular endothelial cell monolayer formed on membrane filter potentiates the defense against tumor cell invasion by treatment with brefeldin A.
We constructed vascular endothelial cell monolayer on a fibronectin-coated filter in a Boyden chamber and assessed the ability of 3 LL cells to penetrate through the artificial blood vessel wall. The defense of endothelial cell monolayers against the tumor cell invasion was greatly potentiated by their pretreatment with 5 or 10 micrograms/ml of brefeldin A (BFA) for 1 h (52% or 28% of control invasion). Treatment of the endothelial cell monolayers with BFA resulted in an increase in the release of inhibitory material(s) against urokinase-type plasminogen activator (u-PA) activity of 3 LL cells. Parallel experiments with the cultured endothelial cells and BFA indicated that the fungal metabolite enhanced a rate of accumulation of plasminogen activator inhibitor-1 (PAI-1) antigen, but not of tissue-type plasminogen activator antigen in the medium. The BFA-induced enhancement of PAI-1 antigen release was accompanied with the increased accumulation of the extracellular (membrane/matrix-bound) and intracellular PAI-1 antigen (219% of control at 24 h). These results suggest that BFA can strengthen the defense of vascular endothelium against tumor-cell invasion by enhancing the release and accumulation of PAI-1, which plays a critical role in the regulation of the u-PA-plasmin-collagenase activation cascade.
Soeda
S
S
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Fukuoka University, Japan.
Honda
O
O
Shimeno
H
H
D020126:Brefeldin A; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D017364:Collagenases / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D009361:Neoplasm Invasiveness / Q000517:prevention & control*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D010959:Tissue Plasminogen Activator / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014471:Umbilical Veins; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
D003517:Cyclopentanes; D017395:Plasminogen Activator Inhibitor 1; D020126:Brefeldin A; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator; D017364:Collagenases