Neurokinin-1 Receptor Directly Mediates Glioma Cell Migration by Up-regulation of Matrix Metalloproteinase-2 (MMP-2) and Membrane Type 1-Matrix Metalloproteinase (MT1-MMP)

Neurokinin-1 receptor (NK1R) occurs naturally on human glioblastomas. Its activation mediates glioma cell proliferation. However, it is unknown whether NK1R is directly involved in tumor cell migration. In this study, we found human hemokinin-1 (hHK-1), via NK1R, dose-dependently promoted the migration of U-251 and U-87 cells. In addition, we showed that hHK-1 enhanced the activity of MMP-2 and the expression of MMP-2 and MT1-matrix metalloproteinase (MMP), which were responsible for cell migration, because neutralizing the MMPs with antibodies decreased cell migration. The involved mechanisms were then investigated. In U-251, hHK-1 induced significant calcium efflux; phospholipase C inhibitor U-73122 reduced the calcium mobilization, the up-regulation of MMP-2 and MT1-MMP, and the cell migration induced by hHK-1, which meant the migration effect of NK1R was mainly mediated through the G_q-PLC pathway. We further demonstrated that hHK-1 boosted rapid phosphorylation of ERK, JNK, and Akt; inhibition of ERK and Akt effectively reduced MMP-2 induction by hHK-1. Meanwhile, inhibition of ERK, JNK, and Akt reduced the MT1-MMP induction. hHK-1 stimulated significant phosphorylation of p65 and c-JUN in U-251. Reporter gene assays indicated hHK-1 enhanced both AP-1 and NF-κB activity; inhibition of ERK, JNK, and Akt dose-dependently suppressed the NF-κB activity; only the inhibition of ERK significantly suppressed the AP-1 activity. Treatment with specific inhibitors for AP-1 or NF-κB strongly blocked the MMP up-regulation by hHK-1. Taken together, our data suggested NK1R was a potential regulator of human glioma cell migration by the up-regulation of MMP-2 and MT1-MMP.     

The role of IL-18 in the modulation of matrix metalloproteinases and migration of human natural killer (NK) cells

In this study, we examined whether interleukin-18 (IL-18) affects natural killer (NK) cells' migration and matrix metalloproteinases (MMPs) production. We demonstrated that chemotaxis of human NK cells through basement membrane-like Matrigel was augmented by IL-18. As well, IL-18 stimulation induces the production of activated forms of matrix metalloproteinase-2 (MMP-2) as well as the production of pro-MMP-2 from NK cells. We also demonstrated that MT1-MMP expression on human NK cells, which is a major activator of MMP-2, was induced by IL-18 stimulation coordinated with MMP-2 activation. These data suggest that the MT1-MMP/MMP-2 system participates in the degradation of basement membrane components and thus contributes to NK cell migration.     

Hyaluronan-binding protein 1 (HABP1/p32/gC1qR) induces melanoma cell migration and tumor growth by NF-kappa B dependent MMP-2 activation through integrin α(v)β(3) interaction

Cell migration is the hallmark of cancer regulating anchorage independent growth and invasiveness of tumor cells. Hyaluronan (HA), an ECM polysaccharide is shown to regulate this process. In the present report, we demonstrated, supplementation of purified recombinant hyaluronan binding protein 1(HABP1/p32/gC1qR) from human fibroblast cDNA enhanced migration potential of highly invasive melanoma (B16F10) cells. Exogenous HABP1 adhered to the cell surface transiently and was shown to interact and colocalize with α_vβ₃ integrin, a regulatory molecule of cell migration. In HABP1 treated cells, the phosphorylation of nuclear factor inducing kinase (NIK) and IκBα was observed, followed by nuclear translocation of p65 subunit of NFκB, along with its DNA-binding and transactivation, resulting in upregulation of MT1-MMP expression and finally MMP-2 activation. To substantiate our findings, prior to HABP1 treatment, the expression of NIK was reduced by small interfering RNA mediated knockdown and confirmed the inhibition of nuclear translocation of p65 subunit of NFκB and upregulation of MT1-MMP expression. In addition, the use of curcumin, an anti-cancer drug, or GRGDSP, the blocking peptide along with exogenous HABP1, inhibited such NFκB-dependent pathway, confirming that HABP1-induced cell migration is α_vβ₃ integrin-mediated and downstream signaling by NFκB. Finally, we translated the in vitro data in mice model and observed enhanced tumor growth with higher MT1-MMP expression and MMP-2 activation in the tumors upon injection of HABP1 treated melanoma cells. The treatment of curcumin, the anticancer drug along with HABP1, inhibited the migration, expression of MT1-MMP and activation of MMP-2 and finally tumor growth supports the involvement of HABP1 in tumor formation.     

Differential regulation of membrane type 1-matrix metalloproteinase activity by ERK 1/2- and p38 MAPK-modulated tissue inhibitor of metalloproteinases 2 expression controls transforming growth factor-beta1-induced pericellular collagenolysis

Acquisition of matrix metalloproteinase-2 (MMP-2) activity is temporally associated with increased migration and invasiveness of cancer cells. ProMMP-2 activation requires multimolecular complex assembly involving proMMP-2, membrane type 1-MMP (MT1-MMP, MMP-14), and tissue inhibitor of metalloproteinases-2 (TIMP-2). Because transforming growth factor-beta1 (TGF-beta1) promotes tumor invasion in advanced squamous cell carcinomas, the role of TGF-beta1 in the regulation of MMP activity in a cellular model of invasive oral squamous cell carcinoma was examined. Treatment of oral squamous cell carcinoma cells with TGF-beta1 promoted MMP-dependent cell scattering and collagen invasion, increased expression of MMP-2 and MT1-MMP, and enhanced MMP-2 activation. TGF-beta1 induced concomitant activation of ERK1/2 and p38 MAPK, and kinase inhibition studies revealed a negative regulatory role for ERK1/2 in modulating acquisition of MMP-2 activity. Thus, a reciprocal effect on proMMP-2 activation was observed whereupon blocking ERK1/2 phosphorylation promoted proMMP-2 activation and MT1-MMP activity, whereas inhibiting p38 MAPK activity decreased proteolytic potential. The cellular mechanism for the control of MT1-MMP catalytic activity involved concurrent reciprocal modulation of TIMP-2 expression by ERK1/2 and p38 MAPKs, such that inhibition of ERK1/2 phosphorylation decreased TIMP-2 production, and down-regulation of p38 MAPK activity enhanced TIMP-2 synthesis. Further, p38 MAPK inhibition promoted ERK1/2 phosphorylation, providing additional evidence for cross-talk between MAPK pathways. These observations demonstrate the complex reciprocal effects of ERK1/2 and p38 MAPK in the regulation of MMP activity, which could complicate the use of MAPK-specific inhibitors as therapeutic agents to down-regulate the biologic effects of TGF-beta1 on pericellular collagen degradation and tumor invasion.     

Contrasting expression of membrane metalloproteinases, MT1-MMP and MT3-MMP, suggests distinct functions in skeletal development

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is the most ubiquitous and widely studied of the membrane-type metalloproteinases (MT-MMPs). It was thus surprising to find no published data on chicken MT1-MMP. We report here the characterization of the chicken gene. Its low sequence identity with the MT1-MMP genes of other species, high GC content, and divergent catalytic domain explains the absence of data and our difficulties in characterizing the gene. The absence of structural features in the chicken gene that have been suggested to be critical for the activation of MMP-2 by MT1-MMP; for the effect of MT1-MMP on cell migration and for the recycling of MT1-MMP suggest these features are either not essential or that MT1-MMP does not perform these functions in chickens. Comparison of the expression of chicken MT1-MMP with MT3-MMP and with MMP-2 and MMP-13 has confirmed the previously recognized co-expression of MT1-MMP with MMP-2 and MMP-13 in fibrous and vascular tissues, particularly those surrounding the developing long bones in other species. By contrast, MT3-MMP expression differs markedly from that of MT1-MMP and of both MMP-2 and MMP-13. MT3-MMP is expressed by chondrocytes of the developing articular surface. Similar expression patterns of this group of MT-MMPs and MMPs have been observed in mouse embryos and suggest distinct and specific functions for MT1-MMP and MT3-MMP in skeletal development.     

The type I collagen induction of MT1-MMP-mediated MMP-2 activation is repressed by alphaVbeta3 integrin in human breast cancer cells.

The influence of alphaVbeta3 integrin on MT1-MMP functionality was studied in human breast cancer cells of differing beta3 integrin status. Overexpression of beta3 integrin caused increased cell surface expression of alphaV integrin and increased cellular adhesion to extracellular matrix (ECM) substrates in BT-549, MDA-MB-231 and MCF-7 cells. beta3 integrin expression also enhanced the migration of breast cancer cells on ECM substrates and enhanced collagen gel contraction. In vivo, alphaVbeta3 cooperated with MT1-MMP to increase the growth of MCF-7 cells after orthotopic inoculation in immunocompromised mice, but had no influence on in vitro proliferation. Despite these stimulatory effects, overexpression of beta3 integrin suppressed the type I collagen (Col I) induced MMP-2 activation in all breast cancer cell lines analyzed. This was also evident in extracts from the MCF-7 tumors in vivo, where MMP-2 activation was stimulated by MT1-MMP transfection, but attenuated with beta3 integrin expression. Although our studies confirm important biological effects of alphaVbeta3 integrin on enhancing cell adhesion and migration, ECM remodeling and tumor growth, beta3 integrin caused reduced MMP-2 activation in response to Col I in vitro, which appears to be physiologically relevant, as it was also seen in tumor xenografts in vivo. The reduction of MMP-2 activation (and thus MT1-MMP activity) by alphaVbeta3 in response to Col I may be important in scenarios where cells which are activated for matrix degradation need to preserve some pericellular collagen, perhaps as a substrate for cell adhesion and migration, thus maintaining a balanced level of proteolysis required for efficient tumor growth.     

Rac1 mediates type I collagen-dependent MMP-2 activation. role in cell invasion across collagen barrier

Cell migration and proteolysis are two essential processes during tumor invasion and metastasis. Matrix metalloproteinase (MMP)-2 (type IV collagenase; gelatinase A), is implicated in tumor metastasis as well as in primary tumor growth. The Rho family of small GTPases regulates the dynamics of actin cytoskeleton associated with cell motility. In this report, we provide evidence that Rac1, one member of Rho-related small GTPases, is a mediator of MMP-2 activation in HT1080 fibrosarcoma cells cultured in three-dimensional collagen gel (3D-col) and that MMP-2 activation is required for Rac1-promoted cell invasion through collagen barrier. Stable expression of dominant negative (Rac1V12N17) and constitutively active Rac1 (Rac1V12), respectively, in HT1080 cells demonstrates that Rac1 promoted cell invasiveness across type I collagen and collagen-dependent MMP-2 activation. Active Rac1 is sufficient to induce MMP-2 activation in cells cultured in fibrin gel, an extracellular matrix component that does not support MMP-2 activation. The Rac1-dependent MMP-2 activation occurred in a cell-associated fashion and required MMP activities. Because the cell membrane-mediated MMP-2 activation requires MT1-MMP and low amount of issue inhibitor of matrix metalloproteinase-2 (TIMP-2), their expression was examined. Rac1 modulated MT1-MMP mRNA level and the accumulation of a 43-kDa form of MT1-MMP protein, in correlation with MMP-2 activation profile. However, TIMP-2 expression was independent of Rac1 activity. The coordinate modulation of MMP-2 activity and MT1-MMP expression/processing by Rac1 is consistent with cell collagenolytic activity. The C-terminal hemopexin-like domain of MMP-2, which interferes with the cell membrane activation of MMP-2, reduced Rac1-promoted cell invasiveness as monitored by collagen invasion assay. These results suggest that collagen-dependent MMP-2 activation and MT1-MMP expression/processing contribute to Rac-promoted tumor cell invasion through interstitial collagen barrier.     

Paradigmatic identification of MMP-2 and MT1-MMP activation systems in cardiac fibroblasts cultured as a monolayer

Activations of MMP-2 and membrane type 1-matrix metalloproteinase (MT1-MMP) have been correlated with cell migration, a key cellular event in the wound healing and tissue remodeling. We have previously demonstrated furin-dependent MMP-2 and MT1-MMP activations induced by type I collagen in cardiac fibroblasts. To understand mechanistic aspects of the regulation of MMP-2 and MT1-MMP activations by potential non-matrix factor(s) in cardiac fibroblasts, in the present study, we examined the effects of various agents including concanavalin A (ConA), a proteolytic phenotype-producing agent. We showed that treatment of cells with ConA activated pro-MMP-2, and that this activation concurred with elevated levels of cellular MT1-MMP and TIMP-2. The presence of active MT1-MMP and 43 and 36 kDa processed forms of MT1-MMP in a fraction of intracellular proteins prepared from ConA-treated cells suggests the possible internalization of differential forms of MT1-MMP. The appearance of 36 kDa processed form of MT1-MMP in conditioned media prepared from ConA-treated cells indicates the possible extracellular release of the further processed MT1-MMP fragment. Inhibition of furin in ConA-treated cells attenuated pro-MT1-MMP processing and the cellular TIMP-2 level, plus it reduced cell-released active MMP-2 in a time-dependent manner. These results suggest the involvement of furin in the ConA-induced activations of MT1-MMP and MMP-2. Furthermore, the existence of furin inhibitor-insensitive pro- and active MMP-2 species associated with ConA-treated cells implies that a mechanism independent of furin may perhaps account for the binding of the MMP-2 species to the cells. Supplementary material for this article can be found at http://www.mrw.interscience.wiley.com/suppmat/0730-2312/suppmat/94/suppmat_guo.tif.     

The role of MT2-MMP in cancer progression

The role of MT2-MMP in cancer progression remains to be elucidated in spite of many reports on MT1-MMP. Using a human fibrosarcoma cell, HT1080 and a human gastric cancer cell, TMK-1, endogenous expression of MT1-MMP or MT2-MMP was suppressed by siRNA induction to examine the influence of cancer progression in vitro and in vivo. In HT1080 cells, positive both in MT1-MMP and MT2-MMP, the migration as well as the invasion was impaired by MT1-MMP or MT2-MMP suppression. Also cell proliferation in three dimensional (3D) condition was inhibited by MT1-MMP or MT2-MMP suppression and tumor growth in the nude mice transplanted with tumor cells were reduced either MT1-MMP or MT2-MMP suppression with a prolongation of survival time in vivo. MT2-MMP suppression induces more inhibitory effects on 3D proliferation and in vivo tumor growth than MT1-MMP. On the other hand, TMK-1 cells, negative in MT1-MMP and MMP-2 but positive in MT2-MMP, all the migratory, invasive, and 3D proliferative activities in TMK-1 are decreased only by MT2-MMP suppression. These results indicate MT2-MMP might be involved in the cancer progression more than or equal to MT1-MMP independently of MMP-2 and MT1-MMP.     

膜型基质金属蛋白酶-1在不同内皮细胞株中的表达差异

为研究膜型基质金属蛋白酶-1（membrane-type matrix metalloproteinase-1, MT1-MMP）在血管生物学中的作用机制,比较了3株常用的内皮细胞株：人微血管内皮细胞株HMEC-1、人脐静脉内皮细胞株ECV304和EAhy926中MT1-MMP及与其功能相关的MMP-2,TIMP-2的表达差异.实时PCR 和流式细胞术检测HMEC-1、EAhy926和ECV304中MT1-MMP/MMP-2/TIMP-2的表达,明胶酶谱法分析各细胞株上清中MMP-2的酶活.实时PCR结果显示,3株细胞均表达MT1-MMP与TIMP-2,MT1-MMP在EAhy926中表达最高,TIMP-2在ECV304中表达最高,而仅在EAhy926中检测到MMP-2的表达.流式细胞术和酶谱的结果与PCR结果基本一致.MT1-MMP和MMP-2在典型的大血管内皮细胞株EAhy926中高表达可能与该细胞独特的来源、表型特点和功能有关.     

Proprotein convertases regulate insulin-like growth factor 1-induced membrane-type 1 matrix metalloproteinase in VSMCs via endoproteolytic activation of the insulin-like growth factor-1 receptor

The IGF-1 receptor (IGF-1R) and MT1-MMP are synthesized as larger precursor proproteins, which require endoproteolytic activation by the proprotein convertases (PCs) furin/PC5 to gain full biological activity. The aim of this study was to investigate the contribution of PCs to IGF-1R and/or MT1-MMP activation in vascular smooth muscle cells (VSMCs) as well as VSMC proliferation/migration, which are key elements in vascular remodeling. Furin and PC5 mRNAs and proteins were found in VSMCs. Inhibition of furin-like PCs with the specific pharmacological inhibitor dec-CMK inhibited IGF-1R endoproteolytic activation. Inhibition of IGF-1R maturation abrogated IGF-induced IGF-1R autophosphorylation, PI3-kinase and MAPK induction, as well as VSMC proliferation (p<0.05 vs. controls), whereas it had no effect of PDGF-stimulated signaling pathways or cell growth. Both, IGF-1 and PDGF-BB, induced MT1-MMP expression, but only IGF-1-mediated MT1-MMP induction was inhibited by dec-CMK. Induction of MMP-2 by IGF-1 was inhibited by the PI3-kinase inhibitor wortmannin, but not by the MEK-inhibitor PD98059. Dec-CMK inhibited VSMC chemotaxis comparable to the effects of the MMP-inhibitor GM6001 (both p<0.05 vs. controls), supporting that MMPs are involved. In conclusion, this study demonstrates that targeting furin-like PCs and thus inhibiting IGF-1R activation is a novel target to inhibit IGF-1-mediated signaling and cell functions, such as IGF-1-induced MT1-MMP/MMP-2 in VSMCs.     

Membrane-type 1 matrix metalloproteinase cleaves CD44 and promotes cell migration

Migratory cells including invasive tumor cells frequently express CD44, a major receptor for hyaluronan and membrane-type 1 matrix metalloproteinase (MT1-MMP) that degrades extracellular matrix at the pericellular region. In this study, we demonstrate that MT1-MMP acts as a processing enzyme for CD44H, releasing it into the medium as a soluble 70-kD fragment. Furthermore, this processing event stimulates cell motility; however, expression of either CD44H or MT1-MMP alone did not stimulate cell motility. Coexpression of MT1-MMP and mutant CD44H lacking the MT1-MMP-processing site did not result in shedding and did not promote cell migration, suggesting that the processing of CD44H by MT1-MMP is critical in the migratory stimulation. Moreover, expression of the mutant CD44H inhibited the cell migration promoted by CD44H and MT1-MMP in a dominant-negative manner. The pancreatic tumor cell line, MIA PaCa-2, was found to shed the 70-kD CD44H fragment in a MT1-MMP-dependent manner. Expression of the mutant CD44H in the cells as well as MMP inhibitor treatment effectively inhibited the migration, suggesting that MIA PaCa-2 cells indeed use the CD44H and MT1-MMP as migratory devices. These findings revealed a novel interaction of the two molecules that have each been implicated in tumor cell migration and invasion.     

Tissue inhibitor of matrix metalloproteinase-2 regulates matrix metalloproteinase-2 activation by modulation of membrane-type 1 matrix metalloproteinase activity in high and low invasive melanoma cell lines.

Activation of pro-matrix metalloproteinase (MMP)-2 on the surface of malignant cells by membrane-bound MT1-MMP is believed to play a critical role during tumor progression and metastasis. In this study we present evidence that MT1-MMP plays a key role for the in vitro invasiveness of malignant melanoma. Melanoma cell lines secreted latent MMP-2 when cultured on plastic. However, when cells were grown in floating type I collagen lattices, only high invasive melanoma cells activated proMMP-2. Activation could be inhibited by antibodies against MT1-MMP, by addition of recombinant tissue inhibitor of metalloproteinases (TIMP)-2 and by inhibition of MT1-MMP cleavage. MT1-MMP protein was detected as an inactive protein in all cell lines cultured as monolayers, whereas in collagen gels, active MT1-MMP protein was detected in the membranes of both high and low invasive melanoma cells. Production of TIMP-2 was about 10-fold higher in low invasive cells as compared with high invasive melanoma cells and was further increased in the low invasive cells upon contact to collagen. Thus, in melanoma cells TIMP-2 expression levels might regulate MT1-MMP-mediated activation of proMMP-2. High invasive melanoma cells displayed increased in vitro invasiveness, which was inhibited by TIMP-2. These data indicate the importance of these enzymes for the invasion processes and support a role for MT1-MMP as an activator of proMMP-2 in malignant melanoma.     

Clinical relevance of cyclooxygenase-2 and matrix metalloproteinases (MMP-2 and MT1-MMP) in human breast cancer tissue

Breast cancer (BC) is the most common neoplasm among women in most developed countries, including Egypt. Elevated levels of certain proteins in human BC are associated with unfavorable prognosis and progressive stages of the disease. The aim of our study was to evaluate the protein expression profile and prognostic significance of cyclooxygenase-2 (COX-2), matrix metalloproteinase-2 (MMP-2), MMP-9 and membrane type 1-MMP (MT1-MMP) and their interaction in operable BC patients. The protein expression of COX-2, MMP-2 and MT1-MMP were evaluated by western blot technique, whereas enzymatic activity of MMP-2 and MMP-9 was determined by zymography in 47 breast cancer patients as well as normal adjacent tissues. Also, the correlation between these proteins and age, tumor size, LN stage, TNM stage, estrogen receptor, progesterone receptor, disease-free survival, and overall survival (OS) has been investigated. As compared to adjacent normal tissues, COX-2, MMP-2 and MT1-MMP were over-expressed in 43, 64, and 60 % of tumor tissues, respectively. In the same pattern, the activity of MMP-2 (62 %) and MMP-9 (45 %) was elevated in BC tissues. Multivariate analysis showed a positive correlation between the protein expression of COX-2, MMP-2, and MT1-MMP and the activity of MMP-2 and MMP-9 in BC patients. However, the enzymatic activity showed no correlation with clinicopathological features. This study confirms the preclinical evidence that COX-2 increased the expression of MT1-MMP, which in turn activates MMP-2. The lack of correlation with clinicopathological features, OS or disease-free survival ascertains the complexity of tumor progression and metastasis with many pro- and counter regulatory factors.     

BST-2 binding with cellular MT1-MMP blocks cell growth and migration via decreasing MMP2 activity

MT1-MMP (membrane type 1-matrix metalloproteinase) plays important roles in cell growth and tumor invasion via mediating cleavage of MMP2/gelatinase A and a variety of substrates including type I collagen. BST-2 (bone marrow stromal cell antigen 2) is a membrane tetherin whose expression dramatically reduces the release of a broad range of enveloped viruses including HIV from infected cells. In this study, we provided evidence that both transient and IFN-α induced BST-2 could decrease the activity of MMP2 via binding to cellular MT1-MMP on its C-terminus and inhibiting its proteolytic activity; and finally block cell growth and migration. Zymography gel and Western blot experiments demonstrated that BST-2 decreased MMP2 activity, but no effect on the expression of MMP2 and MT1-MMP genes. Confocal and immunoprecipitation data showed that BST-2 co-localized and interacted with MT1-MMP. This interaction inhibited the proteolytic enzyme activity of MT1-MMP, and blocked the activation of proMMP2. Experimental results of C-terminus deletion mutant of MT1-MMP showed that activity of MMP2 was no change and also no interaction existed between the mutant and BST-2 after co-transfection with the mutant and BST-2. It meant that C-terminus of MT1-MMP played a key role in the interaction with BST-2. In addition, cell growth in 3D type I collagen gel lattice and cell migration were all inhibited by BST-2. Taken together, BST-2, as a membrane protein and a tetherin of enveloped viruses, was a novel inhibitor of MT1-MMP and could be considerable as an inhibitor of cancer cell growth and migration on clinic.     

TGF-β1 facilitates MT1-MMP-mediated proMMP-9 activation and invasion in oral squamous cell carcinoma cells

Matrix metalloproteinase (MMP)-2 and MMP-9, also known as gelatinases or type IV collagenases, are recognized as major contributors to the proteolytic degradation of extracellular matrix during tumor invasion. Latent MMP-2 (proMMP-2) is activated by membrane type 1 MMP (MT1-MMP) on the cell surface of tumor cells. We previously reported that cell-bound proMMP-9 is activated by the MT1-MMP/MMP-2 axis in HT1080 cells treated with concanavalin A in the presence of exogenous proMMP-2. However, the regulatory mechanism of proMMP-9 activation remains largely unknown. Transforming growth factor (TGF)-β1 is frequently overexpressed in tumor tissues and is associated with tumor aggressiveness and poor prognosis. In this study, we examined the role of TGF-β1 on MT1-MMP-mediated proMMP-9 activation using human oral squamous cell carcinoma cells. TGF-β1 significantly increased the expression of MMP-9. By adding exogenous proMMP-2, TGF-β1-induced proMMP-9 was activated during collagen gel culture, which was suppressed by the inhibition of TGF-β1 signaling or MT1-MMP activity. This MT1-MMP-mediated proMMP-9 activation was needed to facilitate TGF-β1-induced cell invasion into collagen gel. Thus, TGF-β1 may facilitate MT1-MMP-mediated MMP-9 activation and thereby stimulate invasion of tumor cells in collaboration with MT1-MMP and MMP-2.     

Modulation of membrane type 1 matrix metalloproteinase by LPS and gamma interferon bound to extracellular matrix in intestinal crypt cells

Membrane type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane protein that participates in the processing and degradation of cell surface proteins and the extracellular matrix (ECM). This enzyme regulates ECM turnover in wound repair, promotes cell migration and activates other MMPs, such as MMP-2, which is involved in angiogenesis, cell migration and tumoral metastasis. An increase in pro-inflammatory cytokine expression, such as gamma interferon (IFN-gamma), has been associated with chronic wounds in inflammatory bowel diseases. However, the extent to which cytokines modulate MT1-MMP has not been totally defined. In this report, the effects of the bacterial lipopolysaccharide (LPS) and ECM-bound IFN-gamma on MT1-MMP expression and MMP-2 activity were evaluated by Western blot, RT-PCR and zymography in isolated intestinal epithelial and cultured HT-29 cells. In the presence of LPS, ECM-bound IFN-gamma, but not soluble IFN-gamma, reduced the enterocyte MT1-MMP protein expression. In addition, the active form of MMP-2 was also decreased in the presence of both LPS and IFN-gamma, indicating that lower MMP-2 activity accompanied the decrease in MT1-MMP expression. These results suggest the possibility that endotoxin and ECM-bound IFN-gamma may affect matrix remodeling by modulating matrix metalloproteinase in enterocytes during wound healing.