Mutational and immunochemical analysis of plasminogen activator inhibitor 1.

Shubeita, Huda E.; Cottey, Theresa L.; Franke, Arthur E.; Gerard, Robert D.

doi:10.1016/s0021-9258(17)44763-6

Cited by 30 publications

(1 citation statement)

References 32 publications

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“…PAI-1 with mutation of Gln 123 to Lys had a specific 100-fold decrease in affinity for VN, but retained full inhibitory activity (Stefansson and Lawrence, 1996). The double point mutant, Arg 346 to Met and Met 347 to Ser (Shubeita et al, 1990), bound to VN with the same affinity as WT PAI-1 but did not inhibit PA activity. We verified that hPAI-1 (WT or mutant forms) interacts efficiently with murine PA and murine VN according to the procedure described previously (Vleugels et al, 2000).…”

Section: Adenovirus-mediated Pai-1 Cdna Transfermentioning

confidence: 98%

The Plasminogen Activator Inhibitor PAI-1 Controls in Vivo Tumor Vascularization by Interaction with Proteases, Not Vitronectin

Bajou

Masson

Gerard

et al. 2001

The Journal of Cell Biology

311

359

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The plasminogen (Plg)/plasminogen activator (PA) system plays a key role in cancer progression, presumably via mediating extracellular matrix degradation and tumor cell migration. Consequently, urokinase-type PA (uPA)/plasmin antagonists are currently being developed for suppression of tumor growth and angiogenesis. Paradoxically, however, high levels of PA inhibitor 1 (PAI-1) are predictive of a poor prognosis for survival of patients with cancer. We demonstrated previously that PAI-1 promoted tumor angiogenesis, but by an unresolved mechanism. We anticipated that PAI-1 facilitated endothelial cell migration via its known interaction with vitronectin (VN) and integrins. However, using adenoviral gene transfer of PAI-1 mutants, we observed that PAI-1 promoted tumor angiogenesis, not by interacting with VN, but rather by inhibiting proteolytic activity, suggesting that excessive plasmin proteolysis prevents assembly of tumor vessels. Single deficiency of uPA, tissue-type PA (tPA), uPA receptor, or VN, as well as combined deficiencies of uPA and tPA did not impair tumor angiogenesis, whereas lack of Plg reduced it. Overall, these data indicate that plasmin proteolysis, even though essential, must be tightly controlled during tumor angiogenesis, probably to allow vessel stabilization and maturation. These data provide insights into the clinical paradox whereby PAI-1 promotes tumor progression and warrant against the uncontrolled use of uPA/plasmin antagonists as tumor angiogenesis inhibitors.

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Section: Adenovirus-mediated Pai-1 Cdna Transfermentioning

confidence: 98%

The Plasminogen Activator Inhibitor PAI-1 Controls in Vivo Tumor Vascularization by Interaction with Proteases, Not Vitronectin

Bajou

Masson

Gerard

et al. 2001

The Journal of Cell Biology

311

359

View full text Add to dashboard Cite

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Both u‐PA inhibition and vitronectin binding by plasminogen activator inhibitor 1 regulate HT1080 fibrosarcoma cell metastasis

Praus¹,

Collen²,

Gerard³

2002

Intl Journal of Cancer

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Cell migration through tissues occurs in a multitude of physiologic and pathologic processes, including embryonic development, inflammation, wound healing and tumor metastasis. Migration requires the directed formation and detachment of cellular contacts whose stability is regulated both by differential expression of adhesion molecules and the induction of pericellular proteolysis, which modulates cell detachment. Integrins are transmembrane proteins that form heterodimers whose binding to an array of different ligands is involved both in the interactions between individual cells and in their adhesion to the extracellular matrix (ECM). 1 A number of molecules of the fibrinolytic system not only control plasminogen activation but also interact with cellular and matrix molecules to modify cell-matrix contacts and regulate cell migration. The activation of plasminogen to plasmin, a broadspectrum serine protease that catalyzes matrix degradation either directly or indirectly via activation of metalloproteinases, 2 is controlled by 2 physiologic plasminogen activators. Tissue-type plasminogen activator (t-PA) maintains vascular patency by removing intravascular fibrin deposits, 3 and the biologic function of urokinase plasminogen activator (u-PA) is the control of pericellular proteolysis. 4 u-PA binds to a cellular receptor (u-PAR) that localizes u-PA activity to focal adhesion sites by interacting with ␤1 and ␤3 integrins in the presence of vitronectin. 5 Like integrins, u-PA 6 and u-PAR 7 interact with the ECM via binding to vitronectin. Cleavage of u-PAR by u-PA abolishes u-PAR:vitronectin interaction. 8,9 Binding of u-PA to vitronectin has been reported to stimulate plasminogen activation, 10 and u-PA activity is inhibited by the irreversible plasminogen activator inhibitors (PAI), PAI-1 and PAI-2. PAI-1 can be readily detected in plasma and is found in many different tissues. 11 PAI-1 is secreted as an active serine protease inhibitor whose activity is stabilized by vitronectin binding 12 both in plasma and in ECM. Although PAI-1 can reduce cell migration independently of its u-PA inhibitory activity by competing for an integrin binding site on vitronectin, 13,14 it may also promote cellular migration by decreasing cell adhesion to vitronectin. 15 Since adenoviral vectors facilitate expression of recombinant proteins in a wide variety of cells and tissues, they are useful tools to compare the biologic effects of transgenes in defined cell populations, tissues and organs. It has been previously demonstrated that metastasis of HT1080 cells is dependent on u-PAmediated plasmin generation and can be modulated by adenoviral gene transfer of u-PA and its inhibitors. 16 Since blood flow to developing tumors was unaffected by PAI-1 gene transfer, 16 this effect could not be attributed to a reduction in tumor vascularization, but rather to a direct effect on cell migration and metastasis to target organs. However, other studies 17,18 have shown a requirement for angiogenesis in tumor invasion and the essential role fulf...

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Preliminary x‐ray analysis of crystals of plasminogen activator inhibitor‐1

Goldsmith¹,

Sheng-Cheng

Danley

et al. 1991

Proteins

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Crystals of bacterially expressed plasminogen activator inhibitor (PAI-1) suitable for X-ray diffraction analysis have been obtained from 8% (w/v) PEG 1500, pH 8.25. The space group is P1, and the lattice constants are a = 82.17 A, b = 47.82 A, c = 62.89 A, alpha = 90.00 degrees, beta = 106.90 degrees, gamma = 106.84 degrees. The diffraction limit is 2.3 A, and the unit cell contains two molecules of PAI-1. The crystals contain latent PAI-1 which can be partly reactivated by exposure to denaturants.

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Mutational and immunochemical analysis of plasminogen activator inhibitor 1.

Cited by 30 publications

References 32 publications

The Plasminogen Activator Inhibitor PAI-1 Controls in Vivo Tumor Vascularization by Interaction with Proteases, Not Vitronectin

The Plasminogen Activator Inhibitor PAI-1 Controls in Vivo Tumor Vascularization by Interaction with Proteases, Not Vitronectin

Both u‐PA inhibition and vitronectin binding by plasminogen activator inhibitor 1 regulate HT1080 fibrosarcoma cell metastasis

Preliminary x‐ray analysis of crystals of plasminogen activator inhibitor‐1

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