Protein S, an antithrombotic factor, is synthesized and released by neural tumor cells.
Protein S, an anticoagulant factor in the protein C antithrombotic pathway, was found to be synthesized and released by six tumor cell lines of neural origin by western blotting and ELISA. The rate of synthesis ranged from three- to 11-fold higher than that of a microvascular endothelial cell line and 36-144% that of a hepatoma cell line. The secreted protein S displayed specific anticoagulant activity similar to that of purified plasma protein S, implying that it was fully gamma-carboxylated. Ten primary brain tumor tissues also expressed protein S antigen, as shown by western blot analysis. Expression of anticoagulantly active protein S by neural cells raises important questions concerning possible physiologic roles for this multidomain protein beyond its function in control of thrombosis.
Hematologic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333.
D J
DJ
Phillips
J S
JS
Greengard
J A
JA
Fernandez
M
M
Ribeiro
B L
BL
Evatt
J H
JH
Griffin
W C
WC
Hooper
D015153:Blotting, Western; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005343:Fibrinolytic Agents / Q000378:metabolism*; D017293:Protein S / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000378:metabolism
D005343:Fibrinolytic Agents; D017293:Protein S