HT-1080 fibrosarcoma cell matrix degradation and invasion are inhibited by the matrix-associated serine protease inhibitor TFPI-2/33 kDa MSPI

Abstract

The urokinase‐urokinase receptor system plays a dominant role in the degradation and invasion of extracellular matrix (ECM) by tumor cells. In this system, urokinase bound to its cell receptor converts plasminogen to plasmin, a broad‐spectrum serine protease that participates in the degradation and invasion of connective tissues by tumor cells. In this study, we evaluated whether these activities of plasmin are inhibited by a newly characterized human 32 kDa recombinant serine protease inhibitor called trypsin/tissue factor pathway inhibitor‐2 (rTFPI‐2). We found that rTFPI‐2 dose‐dependently inhibited fluid‐phase plasmin as well as plasmin generated on the ECM and/or the cell surface of HT‐1080 fibrosarcoma cells. The degradation of radiolabeled matrix as well as Matrigel invasion by these tumor cells is also inhibited by rTFPI‐2 in a dose‐dependent fashion. We have reported that rTFPI‐2 is identical to 33 kDa extracellular matrix‐associated serine protease inhibitor (33 kDa MSPI), whereas the 31 and 27 kDa MSPIs are under‐glycosylated forms of the 33 kDa MSPI. We therefore evaluated the ability of MSPIs from the ECM of dermal fibroblasts to inhibit plasmin and found that the plasmin activity was effectively blocked by the MSPIs. We have also evaluated whether the HT‐1080 cells synthesize and secrete the MSPIs and found that the synthesis and secretion of the MSPIs was undetectable in these cells. Collectively, our results suggest that rTFPI‐2/33 kDa MSPI inhibits plasmin on the tumor cell and ECM surfaces as well as the degradation and invasion of matrix by HT‐1080 fibrosarcoma cells. Int. J. Cancer 76:749–756, 1998.© 1998 Wiley‐Liss, Inc.

Platelets Contain Tissue Factor Pathway Inhibitor-2 Derived from Megakaryocytes and Inhibits Fibrinolysis

“…3B). The presence of TFPI-2 in the ECM of MEG-01 cells is consistent with the earlier data obtained using ECM from different cell types (6,23,27).…”

“…The role of TFPI-2 in regulating ECM turnover and tumor invasion has been well documented and reviewed (8,9,27,30). However, whether or not TFPI-2 plays a role in regulating blood coagulation and/or fibrinolysis remains uncertain.…”

“…Three variants of molecular mass ϳ27, ϳ31, and ϳ33 kDa are synthesized by these cells and represent differentially glycosylated forms (4,6). Taken together, the secretion of TFPI-2 into the extravascular space regulates ECM turnover and tumor invasion (9,(27)(28)(29) by a mechanism that involves its inhibitory activity toward plasmin (30).…”

A novel function of tissue factor pathway inhibitor-2 (TFPI-2) in human glioma invasion

“…As an ECM-associated serine protease inhibitor (Rao et al, 1996). A previous study of recombinant TFPI-2 showed that TFPI-2 inhibited the generation of plasmin at the surfaces of ECM and HT-1080 ®brosarcoma cells and inhibited the degradation and invasion of matrix by these cells (Rao et al, 1998). TFPI-2 directly inhibits plasmin, thereby releasing growth factors from ECM and activating transforming growth factor b and certain pro-MMPs by tumor cells, which causes degradation of ECM followed by invasion (Kwaan, 1992;Rao et al, 1999).…”

“…The TFPI-2 gene has been mapped to chromosome 7q22 by¯uoresence in situ hybridization (Miyagi et al, 1996b). Recombinant TFPI-2 inhibited plasmin, regardless of whether the enzyme was associated with tumor cells or with ECM, and inhibited matrix degradation and Matrigel invasion by HT-1080 ®brosarcoma cells (Rao et al, 1998).…”