Function of alpha3beta1-tetraspanin protein complexes in tumor cell invasion. Evidence for the role of the complexes in production of matrix metalloproteinase 2 (MMP-2)

Tumor cell migration through the three- dimensional extracellular matrix (ECM) environment is an important part of the metastatic process. We have analyzed a role played by the integrin-tetraspanin protein complexes in invasive migration by culturing MDA-MB-231 cells within Matrigel. Using time-lapse video recording, we demonstrated that the Matrigel-embedded cells remain round and exhibit only limited ability for migration by extending short, highly dynamic pseudopodia. The alpha3beta1-tetraspanin protein complexes were clustered on the thin microvilli-like protrusions extending from both the main cell body and pseudopodia. Ligation of the alpha3beta1-tetraspanin protein complexes with monoclonal antibodies specifically stimulates production of matrix metalloproteinase 2 (MMP-2) and induces formation of long invasive protrusions within Matrigel. Accordingly, treatment with the monoclonal antibodies to various tetraspanin proteins and to the alpha3 integrin subunit increases invasive potential of the MDA-MB-231 cells in the Matrigel-penetration assay. A specific inhibitor of phosphoinositide 3-kinase (PI3K), LY294002, negated the effect of the monoclonal antibodies on the morphology of the Matrigel-embedded cells and on production of MMP-2. Interestingly, broad-spectrum inhibitors of protein tyrosine kinases (genistein) and protein tyrosine phosphatases (orthovanadate), and actin filament stabilizing compound (jasplakinolide), also block protrusive activity of the Matrigel-embedded cells but have no effect on the production of MMP-2. These results indicate that alpha3beta1-tetraspanin protein complexes may control invasive migration of tumor cells by using at least two PI3K-dependent signaling mechanisms: through rearrangement of the actin cytoskeleton and by modulating the MMP-2 production.

Influenza A virus infection modulates the expression of type IV collagenase in epithelial cells

We investigated the effect of influenza A/Beijing/353/89 (H3N2) virus infection on the expression of type IV collagenase in two different types of epithelial cell. Depending on the cell line infected, the viral infection caused changes in the expression of type IV collagenase. The expression of matrix metalloproteinase-9 (MMP-9; 92 kDa) but not of matrix metalloproteinase-2 (MMP-2; 72 kDa) was stimulated in Vero cells. In MDCK cells, the MMP-2 production increased with the virus infection. According to the enzymatic activity revealed with zymography, the MMP-9 promoter activity rose by a factor of over 1788 in influenza A virus-infected Vero cells but not in MDCK cells. The tissue inhibitor of metalloproteinase, TIMP-1, had increased slightly (2.3-fold) in Vero cells 48 hours after the infection, but in MDCK cells, influenza A virus had no effect on the TIMP-1 expression. In conclusion, the MMP-9 and -2 expression by influenza A virus infection are modulated at transcriptional level, depending on the epithelial cell line.

The expression of MMP-2 and TIMP-2 in patients with primary colorectal adenocarcinoma: correlation with liver metastasis

The expression of MMP-2 and TIMP-2 was examined immunohistochemically in a total of 36 colorectal cancer patients with synchronous liver metastasis at the time of surgery, and the serum MMP-2 and TIMP-2 levels were also measured in a total of 58 colorectal cancer patients with/without liver metastasis following primary colorectal surgical resection for serological comparison. Although MMP-2 exhibited a significant expression immunohistochemically in the primary colorectal cancer (p<0.05) and TIMP-2 in the synchronous liver metastasis (p<0.01), there was no relationship between the absence/presence of liver metastasis and serum MMP-2 and TIMP-2 levels, respectively. These results suggest that it can be considered difficult to use serum MMP-2 and TIMP-2 levels to predict the status of liver metastasis following primary resection in patients with colorectal adenocarcinoma.

Matrix metalloproteinase 2 (gelatinase A) is related to migration of keratinocytes

The role of matrix metalloproteinases (MMPs) in cell migration was studied by measuring cell growth, migration, and production of MMP-2 and -9 in oral mucosal and skin keratinocytes cultured in the presence of synthetic MMP inhibitors. MMP-2 was the major gelatinolytic MMP produced by these cells while MMP-9 was produced at a low basal level. Inhibitor effects on MMP-9 production were therefore studied in keratinocytes stimulated by tumor necrosis factor alpha (TNFalpha). Tetracycline analogues at concentrations that inhibited the production of MMP-2 but not MMP-9 were able to drastically inhibit migration of both mucosal and skin keratinocytes. Tetracycline analogues also inhibited keratinocyte growth, an effect not found for the other inhibitors tested. Heterocyclic carbonate-derived compounds (LWs) that inhibited MMP-9 but not MMP-2 production had no effect on cell migration. Batimastat, a potent MMP inhibitor, did not have any effect on MMP production or cell growth but did inhibit keratinocyte migration. Tumor growth factor beta (TGFbeta) increased keratinocyte migration as well as both cell-associated and secreted MMP-2 production in wounded cell cultures. The secreted enzyme was partially converted into an active form. In this model batimastat totally blocked TGFbeta-promoted keratinocyte migration. Immunostaining of keratinocytes advancing into the wound revealed that MMP-2 was localized in extracellular matrix contactlike structures against the endogenously produced laminin-5-rich matrix. MMP-9 was localized diffusely along the cell membranes. Using in situ hybridization we observed that in chronically inflamed human gingiva MMP-2 is expressed in epithelium extending into subepithelial connective tissue. These results suggest that MMP-2 plays a specific role in epithelial migration, possibly by detaching the advancing cells from the pericellular matrix or by activating other MMPs.

RalA requirement for v-Src- and v-Ras-induced tumorigenicity and overproduction of urokinase-type plasminogen activator: involvement of metalloproteases

Overproduction of urokinase-type plasminogen activator (uPA) and metalloproteases (MMPs) is strongly correlated with tumorigenicity and with invasive and metastatic phenotypes of human and experimental tumors. We demonstrated previously that overproduction of uPA in tumor cells is mediated by a phospholipase D (PLD)- and protein kinase C-dependent mechanism. The oncogenic stimulus of v-Src and v-Ras results in the activation of PLD, which is dependent upon the monomeric GTPase RalA. We have therefore investigated whether RalA plays a role in uPA and MMP overproduction that is observed in response to oncogenic signals. We report here that NIH3T3 cells transformed by both v-Src and v-Ras, constitutively overproduce uPA and that expression of a dominant negative RalA mutant (S28N) blocks overproduction of uPA in both the v-Src-and v-Ras-transformed cells. v-Src and v-Ras also induced an upregulation of the activity of MMP-2 and MMP-9 as detected by zymograms, however only the v-Src induction correlated with MMP protein levels detected by Western blot analysis. The dominant negative RalA mutant blocked increased MMP-2 and 9 overproduction induced by v-Src, but not the increased activity of MMP-2 and 9 induced by v-Ras. And, consistent with a role for the RalA/PLD pathway in mitogenesis and tumor development, the dominant negative RalA mutant completely blocked tumor formation by v-Src- and v-Ras-transformed NIH3T3 cells injected subcutaneously in syngeneic mice. The data presented here implicate RalA and PLD as signaling mediators for tumor formation and protease production by transformed cells.

Diminished matrix metalloproteinase 2 (MMP-2) in ectomesenchyme-derived tissues of the Patch mutant mouse: regulation of MMP-2 by PDGF and effects on mesenchymal cell migration

Platelet-derived growth factors (PDGF) regulate cell proliferation, survival, morphology, and migration, as well as deposition and turnover of the extracellular matrix. Important roles for the A form of PDGF (PDGF-A) during connective tissue morphogenesis have been highlighted by the murine Patch mutation, which includes a deletion of the alpha subunit of the PDGF receptor. Homozygous (Ph/Ph) embryos exhibit multiple connective tissue defects including cleft face (involving the first branchial arch and frontonasal processes), incomplete heart septation, and heart valve abnormalities before they die in utero. Analyses of the cell biology underlying the defects in Ph/Ph embryos have revealed a deficit in a matrix metalloproteinase (MMP-2) and one of its activators (MT-MMP) that are likely to be involved in cell migration and tissue remodeling, two processes necessary for normal cardiac and craniofacial development. Morphogenesis of these structures requires infiltration of ectomesenchymal precursors and their subsequent deposition and remodeling of extracellular matrix components. First branchial arch and heart tissue from E10.5 embryos were examined by gelatin zymography and RT-PCR in order to characterize the expression of MMPs in these tissues. Of the MMPs examined, only MMP-2 and one of its activators, MT-MMP, were expressed in the first arch and heart at this stage of development. Tissues from Ph/Ph embryos exhibited a significant decrease in both MMP-2 and MT-MMP compared to tissues from normal embryos of the same developmental stage. In order to assess whether this decrease affects the motile activity of mesenchymal cells, cell migration from Ph/Ph branchial arch explants was compared to migration from normal arch tissue and found to be significantly less. In addition, the migratory ability of branchial arch cells from normal explants could be reduced in a similar manner using a specific MMP inhibitor. Although it is still unclear whether the MMP-2 reduction is a direct result of the absence of response of Ph/Ph cells to PDGF-A treatment of normal branchial arch cells in vitro with recombinant PDGF-AA significantly upregulated MMP-2 protein. Together, these results suggest that PDGF-A regulates MMP-2 expression and activation during normal development and that faulty proteinase expression may be at least partially responsible for the developmental defects exhibited by Ph/Ph embryos.

Gelatinase A expression in endothelial cells is regulated by at least two cis-acting promoter elements

Increased expression of gelatinase A is associated with both angiogenesis and alterations in blood vessel structure. Heart-derived endothelial cells derived from spontaneously hypertensive rats (SHR) were found to express significantly more gelatinase A in culture, both at the protein and mRNA level, than endothelial cells from normotensive Wistar-Kyoto (WKY) rats. Other matrix metalloproteinases, as well as their tissue inhibitors, were not differentially regulated. A 1683 bp gelatinase A promoter fragment linked to a luciferase reporter demonstrated up to 40-fold more activity when transfected into SHR-derived cells versus WKY-derived cells. The promoter region between -1324 and -1272, previously termed RE1, contributed up to a five-fold increase in basal promoter activity in both cells, but contributed only 12% of the promoter activity in SHR-derived cells compared to 85% in WKY-derived cells. In SHR-derived cells, but not in WKY-derived cells, a second region between -1435 and -1375, termed RE2, contributed 60% of the total activity of the 1683 bp promoter fragment. Both electrophoretic mobility shift assays and Southwestern blots demonstrated differences in RE2-specific binding factors in nuclear extracts derived from the two cell types. SHR-derived endothelial cells thus represent a new model system to study the regulation of gelatinase A expression, which itself may contribute to the abnormal vascular structure seen in the SHR.

Suppression of prostate cancer invasive potential and matrix metalloproteinase activity by E-cadherin transfection

Our previous studies have demonstrated the heterogeneous expression of E-cadherin in a Dunning rat prostate tumor model. From this model, cloned E-cadherin-negative cells exhibited enhanced invasive and metastatic potential when compared with E-cadherin-positive cells. In this report, we examined the invasion suppressor function of E-cadherin in these prostate tumor cell clones. The E-cadherin gene was stably transfected into E-cadherin-negative Dunning clones. E-cadherin transfection resulted in the up-regulation of the three major catenins (alpha-, beta-, and gamma-catenin) and enhanced Ca2+-dependent cellular cohesiveness. Morphological analyses of E-cadherin transfectants revealed a reversion from a fibroblastic, motile phenotype to a more stationary epithelial phenotype. Matrix metalloproteinase 2, an important marker associated with invasive and metastatic potential, was reduced in all six stable transfected lines. A concomitant decrease in cellular invasiveness was observed, as assessed in vitro by the ability of the transfected cells to invade biological matrices. These results lend further support to the hypothesis that in this experimental system, E-cadherin plays a central role in reducing the cellular invasiveness of prostatic adenocarcinoma, due in part to the down-regulation of matrix metalloproteinase 2 activity. Moreover, the data shed additional light on the possible mechanisms involved in E-cadherin-dependent modulation of invasion.

Matrix metalloproteinase synthesis and expression in isolated LV myocyte preparations

In several cardiac disease states, alterations in myocyte and extracellular matrix (ECM) structure occur with left ventricular (LV) remodeling and are associated with changes in matrix metalloproteinase (MMP) activity. Although nonmyocyte cell types have been implicated as sites for synthesis and expression of MMPs within the ECM, whether the LV myocyte itself expresses specific types and active forms of MMPs remains unknown. Accordingly, isolated Ca(2+)-tolerant LV porcine myocytes (10(5) cells/ml) in which selective disaggregation and resuspension was performed (13 independent experiments) were plated on basement membrane substrates including Matrigel, collagen IV, laminin, and fibronectin as well as poly-L-lysine. After 24-h incubation, LV myocyte conditioned media were subjected to zymography, a specific MMP-2 proteolytic capture assay, immunoblotting, and ELISA for detection of MMP activity and relative content of the 72-kDa gelatinase MMP-2. Although robust zymographic activity [(pixels. mm(2))/cell] was observed in conditioned media from LV myocytes plated on collagen IV (1,673 +/- 297), fibronectin (1,530 +/- 281), and poly-L-lysine (2,545 +/- 560), proteolytic activity appeared to be lower in conditioned media from LV myocytes plated on Matrigel (842 +/- 83) and laminin (1,329 +/- 238). MMP-2 proteolytic activity was increased by approximately eightfold in conditioned media taken from LV myocytes plated on poly-L-lysine compared with that of Matrigel. With respect to each of the adhesion substrates, MMP-2 content was at least 50% lower in LV myocyte conditioned media taken from Matrigel and laminin. Immunofluorescent labeling of LV myocytes yielded a strong signal for MMP-2 within the myocyte and along the sarcolemmal surface. In conclusion, this study demonstrated for the first time that adult LV myocytes synthesize and express members of the MMP family and thus may potentially participate in the LV remodeling process through synthesis and secretion of MMPs.

Matrix metalloproteinases-2 and -9 and their inhibitors are produced by the human uterine cervix but their secretion is not regulated by nitric oxide donors

We have investigated the presence of matrix metalloproteinases (MMP)-2 and -9 and their tissue inhibitors (TIMP) in the human uterine cervix. We postulate that during the process of cervical ripening, there is an increase in the activity of MMP in order to facilitate cervical connective tissue change. We have previously demonstrated that nitric oxide (NO) donors induce cervical ripening in vivo. A secondary hypothesis is that NO donors regulate MMP activity within the human uterine cervix. Cervical tissue biopsies were obtained from both pregnant and non-pregnant subjects. Cervical fibroblasts were cultured from the non-pregnant tissue. MMP-2 was present in conditioned media from pregnant and non-pregnant cervical explants and non-pregnant cervical fibroblasts. MMP-9 secretion was only detected in explants from non-pregnant women. TIMP-1, -2 and -4 were released by all cervical explants and fibroblast preparations. Pregnant women, in the first trimester, were treated with an NO donor (isosorbide mononitrate) in vivo. Cervical explants and fibroblasts from non-pregnant women were treated with the NO donor spermine nonoate in vitro. Treatment with an NO donor either in vivo or in vitro had no effect on the secretion of the MMP or TIMP studied. Further studies evaluating the mechanisms involved in cervical ripening are required.

Regulation of matrix metalloproteinase-2 (MMP-2) by hepatocyte growth factor/scatter factor (HGF/SF) in human glioma cells: HGF/SF enhances MMP-2 expression and activation accompanying up-regulation of membrane type-1 MMP

Hepatocyte growth factor/scatter factor (HGF/SF) contributes to the malignant progression of human gliomas. We investigated the effect of HGF/SF on matrix metalloproteinase-2 (MMP-2), membrane type 1 matrix metalloproteinase (MT1-MMP) and tissue inhibitors of metalloproteinases (TIMPs), expressions of c-Met/HGF receptor-positive human glioblastoma cells. Treatment of U251 human glioblastoma cells with HGF/SF resulted in enhanced secretion of MMP-2 with an increased level of the active form. This was accompanied by enhanced expression (2.5-fold) of mRNA specific for MMP-2. The stimulatory effect of HGF/SF on MMP-2 expression did not occur in the presence of herbimycin A, a protein tyrosine kinase inhibitor. MT1 -MMP, a cell-surface activator of proMMP-2, was also up-regulated by HGF/SF in a dose-dependent manner. By contrast, the level of TIMP- 1 mRNAs was not altered significantly and that of TIMP-2 was reduced mildly by the HGF/SF treatment, suggesting that HGF/SF may eventually modulate a balance between MMP-2 and TIMPs in favor of the proteinase activity in the glioma cell microenvironment. HGF/SF also stimulated MMP-2 expression of other glioblastoma cell lines. Since glioblastomas frequently co-express HGF/SF and its receptor, our results suggest that HGF/SF might contribute to the invasiveness of glioblastoma cells through autocrine induction of MMP-2 expression and activation.

Mitogen-activated protein kinase (MAPK) regulates the expression of progelatinase B (MMP-9) in breast epithelial cells

Mitogen-activated protein kinases (MAPKs) play a major role in the mitogenic signal transduction pathway and are essential components of both growth and differentiation. Constitutive activation of the MAPK cascade is associated with the carcinogenesis and metastasis of human breast and renal cell carcinomas. The gelatinases B (MMP-9) and A (MMP-2) are 2 members of the matrix metalloproteinase (MMPs) family which are expressed in human cancers and thought to play a critical role in tumor cell invasion and metastasis. In a previous study, we have shown that EGF and amphiregulin upregulate MMP-9 in metastatic SKBR-3 cells but have no effect on MMP-2 secretion. We now investigated specific step(s) in EGF-induced signalling associated with regulation of cell proliferation and MMP-9 induction. EGF-induced signalling in SKBR-3 cells was blocked by relatively specific inhibitors either on ras (FPT inhibitor-1) or P13 kinase (Wortmannin) or by reduction in EGF-induced tyrosine kinase activity (RG 13022). Blocking these signalling pathways significantly inhibited of EGF-induced cell proliferation but only partially reduced in EGF-induced MMP-9 secretion. In contrast, when SKBR-3 cells were exposed to MEK inhibitor (PD 98059) or MAPK inhibitors (Apigenin or MAPK antisense phosphorothioate oligodeoxynucleotides), EGF-induced cell proliferation, MMP-9 induction and invasion through reconstituted basement membrane were significantly reduced. Our results suggest that interfering with MAPK activity may provide a novel means of controlling growth and invasiveness of tumors in which the signalling cascade is activated.

Thrombin stimulates synthesis of type IV collagen and tissue inhibitor of metalloproteinases-1 by cultured human mesangial cells

Glomerular accumulation of extracellular matrix (ECM) is the common pathologic feature following glomerular injury, and the alteration in the synthesis and degradation of ECM may be involved in the glomerular accumulation of ECM. Glomerular fibrin formation occurs in various forms of human and experimental glomerulonephritis, and it may play an important role in progressive glomerular injury. Thrombin, a multifunctional serine proteinase that is generated at the site of vascular injury, has central functions in hemostasis and it also shows various biologic effects. In this study, it is hypothesized that thrombin may alter the production and the degradation of type IV collagen, which is an important component of ECM in the glomeruli. Human mesangial cells (HMC) were cultured, and the levels of type IV collagen, tissue inhibitor of metalloproteinase-1 (TIMP-1), and matrix metalloproteinase-2 (MMP-2) in the culture supernatants were measured by enzyme immunoassay using specific antibodies. MMP-2 activity was also evaluated by zymography using polyacrylamide/ sodium dodecyl sulfate gel-containing gelatin. Thrombin increased the production of type IV collagen and TIMP-1 in a dose-and time-dependent manner, but it did not increase MMP-2. Thrombin also stimulated the gene expressions of the type IV collagen and TIMP-1 in HMC in a dose- and time-dependent manner. Thrombin treated with diisopropylfluorophosphate, a serine proteinase inhibitor, did not show any of these effects. Hirudin, a natural thrombin inhibitor, and anti-transforming growth factor-beta-neutralizing antibody inhibited the stimulating effect of thrombin. These findings suggest that thrombin may contribute to the excessive accumulation of ECM and progression of glomerulosclerosis through an increase of type IV collagen production and a decreased matrix degradation presumably via a transforming growth factor-beta-dependent mechanism.

Expression of metalloproteinase-2 (gelatinase A) in labial salivary glands of patients with Sjögren's syndrome with HTLV-I infection

OBJECTIVE

To determine whether gelatinase A (MMP-2) plays a significant role in the pathogenesis of Sjögren's syndrome (SS) with or without HTLV-I infection.

METHODS

We examined 24 patients with SS (14 HTLV-I-seropositive and 8 HTLV-I-seronegative). Labial salivary gland tissue samples were analysed immunohistochemically using anti-MMP-2 monoclonal antibodies.

RESULTS

In normal salivary glands, MMP-2 expression was not detected. All biopsy samples of 8 SS patients with HTLV-I-associated myelopathy (HAM) and 3 of 6 HTLV-I-seropositive SS patients without manifestation of HAM stained positively for MMP-2. However, the other samples were negative for MMP-2.

CONCLUSION

Our study showed the MMP-2 expression in labial salivary glands of HTLV-I seropositive SS patients, especially in all SS patients with HAM. The presence of MMP-2 in the salivary glands of these patients suggests that it may play a role in cellular infiltration and destruction in salivary glands of SS.

Increased secretion of tissue inhibitors of metalloproteinases 1 and 2 from the aortas of cholesterol fed rabbits partially counterbalances increased metalloproteinase activity

The balance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) plays an important role in extracellular matrix turnover and thereby modulates atherosclerotic plaque development. MMP-1, -2, -3, and -9 activity is increased by atherosclerosis, but the status of TIMPs is less clear. We therefore compared secretion of TIMPs-1 and -2 from cultured aortic explants derived from arch, middle, and distal portions of thoracic aortas of normal rabbits and rabbits fed a 1% cholesterol diet for 8 weeks, using reverse zymography of conditioned media. Cholesterol feeding significantly increased secretion of TIMP-1 from arch and middle portions (both 2.6-fold), accompanied by 2.0- and 2.7-fold increases in TIMP-2, respectively. Atherosclerotic aortas exhibited increased immunoreactive TIMP-1 and TIMP-2 in endothelial cells, smooth muscle cells, and macrophages. Staining of extracellular matrix was also prominent within the noncellular boundary region between fibrous cap and the lipid core, and within the lipid core. Increased TIMP-2 staining was also found in the media subjacent to the lipid core. In situ gelatin zymography demonstrated excess MMP activity within the plaque with partial inhibition in the lipid core base and subjacent media, consistent with the distribution of TIMPs. Casein zymography and in situ zymography demonstrated that increased caseinolytic activity was confined to the pericellular zones of macrophages within the lipid core, again consistent with its restriction by TIMPs. In summary, atherosclerosis increases TIMP expression, which counterbalances, in part, increased MMP activity.

Expression of matrix metalloproteinase 2 (MMP-2), membrane-type 1 MMP and tissue inhibitor of metalloproteinase 2 and activation of proMMP-2 in pancreatic duct adenocarcinomas in hamsters treated with N-nitrosobis(2-oxopropyl)amine

In order to assess the significance of changes in metalloproteinase activity in pancreatic carcinogenesis, the expression of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively), tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2, and membrane-type 1 MMP (MT1-MMP) and MT2-MMP in ductal lesions in a rapid-production model for pancreatic duct carcinomas (PCs) in hamsters initiated with N-nitrosobis(2-oxopropyl)amine (BOP) and in subcutaneous transplantable tumors of hamster pancreatic duct carcinoma (HPDs) was investigated. Northern analysis revealed MMP-2, MMP-9, TIMP-2 and MT1-MMP mRNAs to be overexpressed in PCs. Immunohistochemically, elevated levels of MMP-2 were apparent in early duct epithelial hyperplasias and staining increased from atypical hyperplasias to carcinomas. Gelatin zymography demonstrated clear activation of proMMP-2 but not proMMP-9 in both of primary and HPD tumors, the MT1-MMP mRNA level and proMMP-2 activation being significantly correlated (r = 0.893, P < 0.001). In our rapid production model, 0.1 and 0.2% OPB-3206, an inhibitor of MMPs, given in the diet after two cycles of augmentation pressures for 48 days decreased the incidence and number of carcinomas. Gelatin zymography demonstrated that OPB-3206 inhibited activation of proMMP-2 in pancreatic cancer tissues. These results indicate that overexpression of MMP-2, TIMP-2 and MT1-MMP, and cell surface activation of proMMP-2 by MT1-MMP, are involved in the development of PCs, and that MMP-2 expression at the protein level appears in the early phase of pancreatic duct carcinogenesis. OPB-3206 may be a candidate chemopreventive agent for pancreatic ductal adenocarcinomas.

92K-GL (MMP-9) and 72K-GL (MMP-2) are produced in vivo by human oral squamous cell carcinomas and can enhance FIB-CL (MMP-1) activity in vitro

Previous studies have shown a correlation between the production of certain matrix metalloproteinases (MMPs), especially the gelatinases, by malignant tumors and the progression of these cancers as they invade and metastasize through the extracellular matrix and basement membranes. However, very few of these studies examined this relationship in human oral cancer in vivo, and none addressed the issue of how combinations of the MMPs may further enhance tumor progression. To determine which MMPs are produced in vivo by human oral cancers, we used specific anti-human-MMP antibodies and immunocytochemistry (ICC) methods to examine oral cancer tissue specimens from 20 surgery patients. The ICC data indicated that 72-kDa (72K-GL) and 92-kDa gelatinases (92K-GL) were produced in vivo by discreet clusters of tumor cells and by stromal fibroblasts, vascular endothelial cells (72K-GL), and PMNs (92K-GL). Some stromal fibroblasts near the tumors also appeared to produce fibroblast-type collagenase (FIB-CL), a finding confirmed by Western blot analysis of media conditioned by oral tumor explant cultures. ICC results indicated that 5 of the 20 tumors coincidentally produced all three MMPs. To examine how the two gelatinases and FIB-CL may interact in vitro to degrade fibrillar type I collagen, a major structural component of the extracellular matrix, we used a modified FIB-CL activity assay. Combinations of the gelatinases and FIB-CL were incubated with a 3H-collagen substrate, with the results compared with the combination of stromelysin-1 (SL-1, a superactivator of FIB-CL) and FIB-CL. 92K-GL caused a nine-fold increase in collagenase activity, equivalent to SL-1, while 72K-GL produced a four-fold increase. These results indicate that human oral cancers produce 92K-GL, 72K-GL, and FIB-CL in vivo and that the gelatinases and FIB-CL cooperate to enhance collagen degradation greatly in vitro.

Membrane type 1 matrix metalloproteinase expression in human atherosclerotic plaques: evidence for activation by proinflammatory mediators

BACKGROUND

Matrix metalloproteinases (MMPs) are expressed in atherosclerotic plaques, where in their active form, they may contribute to vascular remodeling and plaque disruption. In this study, we tested the hypothesis that membrane type 1 MMP (MT1-MMP), a novel transmembrane MMP that activates pro-MMP-2 (gelatinase A), is expressed in human atherosclerotic plaques and that its expression is regulated by proinflammatory molecules.

METHODS AND RESULTS

MT1-MMP expression was examined in normal and atherosclerotic human arteries by immunocytochemistry with specific antibodies. MT1-MMP expression in human saphenous vein-derived smooth muscle cells (SMCs) maintained in tissue culture was determined under basal conditions and in response to proinflammatory molecules (interleukin [IL]-1alpha, tumor necrosis factor [TNF]-alpha, and oxidized LDL [ox-LDL]) by use of Northern blot and ribonuclease protection assays for mRNA, Western blot and immunoprecipitation for protein, and gelatin zymography for catalytic activity. Medial SMCs of normal vessel wall expressed MT1-MMP. In atherosclerotic arteries, MT1-MMP expression was noted within the complex atheroma colocalizing with SMCs and macrophages (Mphi). Cultured SMCs constitutively expressed MT1-MMP mRNA and protein, which increased 2- to 4-fold over control in a time-dependent manner within 4 to 8 hours of exposure to IL-1alpha, TNF-alpha, and ox-LDL (thiobarbituric acid-reactive substances, 13.4 nmol/mg LDL protein), whereas native LDL had no effect. Flow cytometry revealed MT1-MMP expression by human monocyte-derived Mphi, which increased 3.8-fold over baseline within 6 hours after exposure to 10 ng/mL TNF-alpha.

CONCLUSIONS

This study demonstrates that MT1-MMP, an activator of pro-MMP-2, is expressed by SMCs and Mphi in human atherosclerotic plaques. Furthermore, proinflammatory molecules upregulate MT1-MMP expression in vascular SMCs and Mphi. Thus, activation of SMCs and Mphi by proinflammatory molecules may influence extracellular matrix remodeling in atherosclerosis by regulating MT1-MMP expression.

Expression of matrix metalloproteinase-1, -2 and -3 in squamous cell carcinoma and actinic keratosis

Matrix metalloproteinase (MMP) plays an important role in extracellular matrix degradation associated with cancer invasion. An expression of MMP-1 (interstitial collagenase), MMP-2 (72-kDa type IV collagenase) and MMP-3 (stromelysin-1) was investigated in squamous cell carcinoma (SCC) and its precancerous condition, actinic keratosis (AK), using in situ hybridization techniques. MMP-1 mRNA was detected in tumour cells and/or in stromal cells in all cases of SCC, four of six AKs adjacent to SCC and four of 16 AKs. MMP-2 and MMP-3 mRNAs were detected in SCC but not in AK. The expression of MMP-3 correlated to that of MMP-1 (P = 0.03) localized at the tumour mass and stroma of the invasive area, while MMP-2 mRNA was detected widely throughout the stroma independent of MMP-1 expression. Our results indicated that the expression of MMP-1, -2 and -3 showed different localization patterns, suggesting a unique role of each MMP in tumour progression. Moreover, MMP-1 expression could be an early event in the development of SCC, and AK demonstrating MMP-1 mRNA, might be in a more advanced dysplastic state, progressing to SCC.

MMP-2 and TIMP-2 expression correlates with poor prognosis in cervical carcinoma--a clinicopathologic study using immunohistochemistry and mRNA in situ hybridization

OBJECTIVE

The spread of malignant neoplasms is closely associated with matrix and basement membrane degradation, mediated by various classes of proteolytic enzymes. Matrix metalloproteinases (MMP) appear to have a key role in the sequence of events that lead to local invasion and metastasis. The present study evaluated the role of matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinases-2 (TIMP-2), and membrane-type metalloproteinase (MT1-MMP) in cervical neoplasia.

METHODS

We have analyzed 49 uterine cervical squamous cell carcinomas, 10 cases of high-grade cervical intraepithelial neoplasia (CIN II-III), and 10 control cervices for the presence of MMP-2, TIMP-2, and MT1-MMP using in situ hybridization. MMP-2 protein expression was evaluated using immunohistochemistry. Results were analyzed for possible correlation with disease outcome.

RESULTS

MMP-2, TIMP-2, and MT1-MMP mRNA were localized to both stromal and tumor cells. However, an intense signal for MMP-2 was detected almost exclusively in tumor cells and was uniformly absent from CIN lesions and control cervices. Conversely, intense signals for TIMP-2 and MT1-MMP were detected in both stromal and tumor cells of invasive carcinomas, more often for the former. As with MMP-2, they were absent from CIN lesions. MMP-2 protein expression was enhanced in tumor cells compared to CIN cases and controls, significantly compared to the latter (P = 0.01). The presence of both MMP-2 and TIMP-2 mRNA in tumor cells correlated with advanced stage (P = 0.003 for MMP-2, P = 0.002 for TIMP-2) and with poor survival (P = 0.003 for MMP-2, P = 0.002 for TIMP-2) in univariate analysis. In addition, their presence in tumor cells intercorrelated (P = 0.002). In multivariate survival analysis, MMP-2 presence retained its association with survival (P = 0.004), in addition to patient age (P = 0.027) and advanced stage (P = 0. 0002).

CONCLUSIONS

Both MMP-2 and TIMP-2 have a key role in extracellular matrix invasion in cervical carcinoma, largely through their elaboration by tumor cells. The presence of mRNA for both proteins is interrelated and is associated with poor survival.

Correlation between expression of matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9) and angiogenesis in colorectal adenocarcinoma

Matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), which degrade extracellular matrix, are believed to play a crucial role in tumor invasion and metastasis. Angiogenesis is also perceived as an important step in tumor growth and metastasis. To investigate the expression of MMPs and the correlation between the expression of MMPs and angiogenesis in colorectal adenocarcinoma, we studied 72 cases of colorectal adenocarcinoma in Inha University Hospital from 1996 to 1997. We evaluated the expression of MMPs by immunohistochemistry and angiogenesis by counting the microvessels. The expression of MMP-2 was increased according to the Astler-Coller stage (p< 0.05). Angiogenesis in the metastatic group was higher than that of the localized one (p<0.05). The expression of MMP-2 positively correlated with angiogenesis (p<0.05), and marked expression of MMP-9 positively correlated with angiogenesis (p<0.05). The present results suggest that the expression of MMP-2 provides clues for tumor progression and angiogenesis provides significant information to predict whether metastasis is present in colorectal adenocarcinoma.

Enhancement of membrane-type 1-matrix metalloproteinase (MT1-MMP) production and sequential activation of progelatinase A on human squamous carcinoma cells co-cultured with human dermal fibroblasts

Matrix metalloproteinase 2 (MMP-2)/gelatinase A plays an important role in tumour invasion and metastasis. Since MMP-2 is secreted as an inactive form (proMMP-2) from tumour and neighbouring stroma cells, the activation process is necessary to express the enzymic activity for degradation of extracellular matrix components. We herein reported that the activation of proMMP-2 was induced in human squamous carcinoma cells co-cultured with normal human dermal fibroblasts. When A431 cells were co-cultured with human fibroblasts at various cell ratios, 72-kDa proMMP-2 was converted to a 62-kDa active form through the appearance of a 64-kDa intermediate. The activation of proMMP-2 by co-culture was also observed in other carcinoma cell lines, HSC-4 and SAS, but not in normal human keratinocytes. We characterized by in vitro invasion assay that A431 cells in co-culture preferentially invaded through Matrigel and the increased invasive activity was inhibited by exogenously adding tissue inhibitor of metalloproteinases 2. The augmented proMMP-2 activation by co-culture was achieved by the increase in membrane type 1-MMP (MT1-MMP) production along with that of its mRNA level. The predominant appearance of MT1-MMP was immunologically observed in A431 cells, but not human fibroblasts of the co-culture. Furthermore, epidermal growth factor (EGF) enhanced the co-culture-mediated proMMP-2 activation by increasing the production and gene expression of MT1-MMP, and thereby tumour invasive activity was further augmented. These results suggest that the cell-cell contact between carcinoma cells and normal fibroblasts enhances the production of MT1-MMP followed by sequential activation of proMMP-2 on the tumour cell surface, which may be closely implicated in tumour invasion in vivo.