Human glioma U‐251 cells contain type 1 plasminogen activator inhibitor in a rapidly releasable form

FEBS Letters

Salonen, Eeva-Marjatta¹  Gombau, Lourdes¹  Schleef, Raymond R.¹  Engvall, Eva² 

[1] Department of Vascular Biology,The Scripps Research Institute, 10666 N. Torrey Pines Rd. La Jolla, CA 92037, USA;The Burnham Institute, 10901 N. Torrey Pines Rd., La Jolla, CA 92037, USA

关键词: Cytoplasmic granule;    Glioma;    Urokinase;    Plasminogen activator;    Plasminogen activator inhibitor;   

DOI  :  10.1016/0014-5793(96)00865-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Because recent information suggests that the localized deposition of protease inhibitors is one mechanism by which cells regulate pericellular proteolysis during tissue invasion, the distribution of type 1 plasminogen activator inhibitor (PAI-1) associated with the invasive human glioma cell line U-251 was investigated. Direct and reverse fibrin zymography indicated the presence of urokinase-like plasminogen activator (u-PA) and PAI-1 in U-251 conditioned media and cell lysates. PAI-1 antigen was detected immunologically in cytoplasmic granules present within cellular processes of U-251 cells and these organelles could be isolated on Percoll density gradients in a high density band. In contrast, u-PA activity and another secreted protein, amyloid β-protein precursor, were only present in the low density region of the gradients. Functional analysis of PAI-1 in the granules contained within the high density fractions revealed the presence of active PAI-1. Incubation of U-251 cells with the secretagogue, 8-bromoadenosine 3′:5′-cyclic monophosphate, resulted in a 3-fold increase in the release of PAI-1 in the media conditioned by these cells. These data suggest that the human glioma cell line U-251 contains PAI-1 in a rapidly releasable form, which may provide another mechanism by which these tumors could regulate proteolytic activity in a localized manner.

【 授权许可】

Unknown