Inter-α-trypsin Inhibitor Bound to Tumor Cells Is Cleaved into the Heavy Chains and the Light Chain on the Cell Surface

Kobayashi, Hiroshi; Gotoh, Junko; Hirashima, Yasuyuki; Terao, Toshihiko

doi:10.1074/jbc.271.19.11362

Cited by 43 publications

(40 citation statements)

References 34 publications

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“…Similar results were also obtained upon incubation of I␣I with tumor cells (40). Whether this cleavage process is of physiological significance remains to be seen.…”

Section: Fig 5 Partial Proteolytic Degradation Of H2supporting

confidence: 76%

Structural Characterization of Inter-α-inhibitor

Blom

Mörgelin

Öyen

et al. 1999

Journal of Biological Chemistry

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Inter-␣-inhibitor (I␣I) is a 180-kDa serum protein consisting of three polypeptides. Two of these, the heavy chains 1 and 2 (H1 and H2), are of 75-80 kDa and have similar amino acid sequences. The third polypeptide, bikunin, has a molecular mass of 25 kDa and contains a 7-kDa chondroitin sulfate chain that is covalently linked to the C-terminal amino acid residues of H1 and H2. I␣I has been shown to be required for the formation of the hyaluronan-containing extracellular matrix of certain cell types. How I␣I exerts this function is not known, but it appears that upon interaction with cells, the heavy chains are released and become covalently linked to hyaluronan. Our results indicate that I␣I and its heavy chains are extended molecules; thus, upon electron microscopy, I␣I appeared to consist of two globular domains connected by a thin structure 31-nm long and the isolated heavy chains of a globular domain and a "tail" about 15-nm long. Analysis of the heavy chains by partial proteolysis showed that the C-terminal halves are particularly sensitive to hydrolysis indicating that they are loosely folded. Furthermore, electron microscopy showed that partially degraded heavy chains lacked the extended regions. Taken together, these results suggest that the N-terminal half of the heavy chains forms a globular domain, whereas the other half has an extended and loosely folded structure.

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“…Similar results were also obtained upon incubation of I␣I with tumor cells (40). Whether this cleavage process is of physiological significance remains to be seen.…”

Section: Fig 5 Partial Proteolytic Degradation Of H2supporting

confidence: 76%

Structural Characterization of Inter-α-inhibitor

Blom

Mörgelin

Öyen

et al. 1999

Journal of Biological Chemistry

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“…We have previously shown that in human umbilical vein endothelial cells and promyeloid leukemia cell line U937 activation of PKC represents a critical event in tumor necrosis factor-triggered signaling cascade leading to uPA secretion (12). Furthermore, we had shown that induction of uPA expression by tumor necrosis factor-␣ was inhibited when these cells were incubated with UTI and that UTI may influence the PKC-dependent protein kinase pathway in uPA expression.…”

Section: Uti Suppresses Pma-triggered Phosphorylation Of Mek1 Erk2mentioning

confidence: 95%

“…Agents that modulate uPA have been shown to alter the rate of metastasis in in vitro experiments and in some animal models (16). Recent publication demonstrated that UTI with anti-inflammatory and anti-tumor promoting properties can influence the PKC-dependent signal pathway in uPA expression in cultured human umbilical vein endothelial cells and in the promyeloid leukemia cell line U937 (12); exogenous UTI inhibits a rapid increase in membrane-associated PKC activity, and a decrease in cytosolic PKC activity. However, the precise molecular mechanisms of the UTI-mediated changes occurring downstream of the PKC signal transduction have remained unclear.…”

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confidence: 99%

“…The UTI gene encodes a Kunitz-type protease inhibitor of molecular mass 40 kDa (9), which is composed of a ligand-binding domain (amino terminus) for cell-associated UTI-binding sites (10,11) and protease inhibitor domain (carboxyl terminus) (9), which effectively inhibits trypsin, plasmin, and granulocyte elastase. In addition to its protease inhibiting effects, UTI plays a role in suppressing urokinase-type plasminogen activator (uPA) production responsible for the invasiveness of tumor cells (12), although UTI does not inhibit directly the catalytic activity of uPA. uPA converts plasminogen into plasmin, a serine protease with broad substrate specificity toward components of the basement membrane and the extracellular matrix including laminin, vitronectin, and fibronectin (13).…”

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confidence: 99%

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Suppression of Urokinase Expression and Invasiveness by Urinary Trypsin Inhibitor Is Mediated through Inhibition of Protein Kinase C- and MEK/ERK/c-Jun-dependent Signaling Pathways

Kobayashi

Suzuki

Tanaka

et al. 2001

Journal of Biological Chemistry

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Urinary trypsin inhibitor (UTI), a Kunitz-type protease inhibitor, interacts with cells as a negative modulator of the invasive cells. Human ovarian cancer cell line, HRA, was treated with phorbol ester (PMA) to evaluate the effect on expression of urokinase-type plasminogen activator (uPA), since the action of uPA has been implicated in matrix degradation and cell motility. Preincubation of the cells with UTI reduced the ability of PMA to trigger the uPA expression at the gene level and at the protein level. UTI-induced down-regulation of PMAstimulated uPA expression is irreversible and is independent of a cytotoxic effect. Down-regulation of uPA by UTI is mediated by its binding to the cells. We next asked whether the mechanism of inhibition of uPA expression by UTI was due to interference with the protein kinase C second messenger system. An assay for PKC activity demonstrated that UTI does not directly inhibit the catalytic activity of PKC and that PMA translocation of PKC from cytosol to membrane was inhibited by UTI, indicating that UTI inhibits the activation cascade of PKC. PMA could also activate a signaling pathway involving MEK1/ERK2/c-Jun-dependent uPA expression. When cells were preincubated with UTI, we could detect suppression of phosphorylation of these proteins. Like several types of PKC inhibitor, UTI inhibited PMA-stimulated invasiveness. We conclude that UTI markedly suppresses the cell motility possibly through negative regulation of PKC-and MEK/ERK/c-Jun-dependent mechanisms, and that these changes in behavior are correlated with a coordinated down-regulation of uPA which is likely to contribute to the cell invasion processes.

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“…In this system, it is clear that HA is the major structural component that determines the viscoelastic properties of the expanding matrix of the cumulus-oophorus. It is well established that members of the I␣I family are pivotal for the formation of the cell-oocyte complexes matrix, where covalent linkage of HC of I␣I (HC1 and HC2) and P␣I (HC3) to HA has been demonstrated (26,27), an interaction that has been postulated to contribute to the stabilization of the ECM (28,29). More recent studies suggest that I␣I components are associated with HA-based cables on colonic smooth muscle cells (30).…”

mentioning

confidence: 99%

Overexpression of Hyaluronan Synthase 2 Alters Hyaluronan Distribution and Function in Proximal Tubular Epithelial Cells

Selbi¹,

Day²,

Rugg³

et al. 2006

Journal of the American Society of Nephrology

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The functional consequences of increased renal cortical hyaluronan that is associated with both acute injury and progressive scarring are unclear. The aim of this study was to characterize hyaluronan synthase-2 (HAS2)-driven HA synthesis and determine its effect on renal proximal tubular epithelial cell (PTC) function, because this is known to be the inducible form of HA synthase in this cell type. Overexpression of HAS2 mRNA increased HA generation, which in the supernatant predominantly was HA of large molecular weight, whereas there was an increase in low molecular weight HA in cellassociated fractions. This was associated with increased expression of hyaluronidases, inhibition of HA cable formation concurrent with reduction in HA-dependent monocyte binding, and increased pericellular HA matrix. Overexpression of HAS2 led to enhanced cell migration. HA can be modified by the covalent attachment of heavy chains that are derived from the serum protein inter-␣-inhibitor (I␣I), a process that is known to be catalyzed by TNF-␣-stimulated gene 6 (TSG-6; an inflammation-associated protein). Enhanced migration was abrogated by blocking antibodies to either I␣I or TSG-6. Addition of recombinant full-length TSG-6 (TSG-6Q) or TSG-6Q_Y94F, a mutant variant with impaired HA binding, increased cell migration. Both of these proteins were able to mediate the covalent transfer of heavy chains, from I␣I and pre-␣-inhibitor, onto HA. Addition of the isolated TSG-6 -Link module (Link_TSG-6), which binds HA but is unable to form covalent complexes with I␣I/pre-␣-inhibitor, had no effect on migration, suggesting that TSG-6 -mediated formation of heavy chain-HA complexes is critical in the formation of a pericellular HA matrix.

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Inter-α-trypsin Inhibitor Bound to Tumor Cells Is Cleaved into the Heavy Chains and the Light Chain on the Cell Surface

Abstract: Inter-␣-trypsin inhibitor (ITI),

Cited by 43 publications

References 34 publications

Structural Characterization of Inter-α-inhibitor

Structural Characterization of Inter-α-inhibitor

Suppression of Urokinase Expression and Invasiveness by Urinary Trypsin Inhibitor Is Mediated through Inhibition of Protein Kinase C- and MEK/ERK/c-Jun-dependent Signaling Pathways

Overexpression of Hyaluronan Synthase 2 Alters Hyaluronan Distribution and Function in Proximal Tubular Epithelial Cells

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