Tissue inhibitor of metalloproteinases-1 (TIMP-1) binds to the cell surface and translocates to the nucleus of human MCF-7 breast carcinoma cells

ADAMTS-1 has nuclear localization in cells with epithelial origin and leads to decreased cell migration

In the study of tumorigenesis, the involvement of molecules within the extracellular matrix (ECM) is crucial. ADAMTSs (A Disintegrin and Metalloproteinase with Thrombospondin motifs), a group of secreted proteases known for their role in ECM remodeling, were primarily considered to be extracellular proteases. However, our research specifically detected ADAMTS-1, a member of this family, predominantly within the nucleus of mammary cells. Our main objective was to understand the mechanism of ADAMTS-1 translocation to the nucleus and its functional significance in this cellular compartment. Our investigation uncovered that nuclear ADAMTS-1 was present in cells exhibiting an epithelial phenotype, while cells of mesenchymal origin contained the protease in the cytoplasm. Moreover, disruption of ADAMTS-1 secretion, induced by Monensin treatment, resulted in its accumulation in the cytoplasm. Notably, our research indicated that alterations in the secretory pathways could influence the protease's compartmentalization. Additionally, experiments with conditioned medium from cells containing nuclear ADAMTS-1 demonstrated its internalization into the nucleus by HT-1080 cells and fibroblasts. Furthermore, heightened levels of ADAMTS-1 within the ECM reduced the migratory potential of mesenchymal cells. This highlights the potential significance of nuclear ADAMTS-1 as a critical component within the tumor microenvironment due to its functional activity in this specific cellular compartment.

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) are localized in the nucleus of retinal Müller glial cells and modulated by cytokines and oxidative stress

Matrix metalloproteinases (MMPs) are involved in the pathology of numerous inflammatory retinal degenerations, including retinitis pigmentosa (RP). Our previous work revealed that intravitreal injections with tissue inhibitor of metalloproteinases 1 (TIMP-1) reduce the progression of rod cell death and inhibit cone cell remodeling that involves reactive gliosis in retinal Müller glial cells (MGCs) in rodent models. The underlying cellular and molecular mechanisms of how TIMP-1 functions in the retina remain to be resolved; however, MGCs are involved in structural homeostasis, neuronal cell survival and death. In the present study, MMP-9 and TIMP-1 expression patterns were investigated in a human MGC line (MIO-M1) under inflammatory cytokine (IL-1β and TNF-α) and oxidative stress (H₂O₂) conditions. First, both IL-1β and TNF-α, but not H₂O_2, have a mild in vitro pro-survival effect on MIO-M1 cells. Treatment with either cytokine results in the imbalanced secretion of MMP-9 and TIMP-1. H₂O₂ treatment has little effect on their secretion. The investigation of their intracellular expression led to interesting observations. MMP-9 and TIMP-1 are both expressed, not only in the cytoplasm, but also inside the nucleus. None of the treatments alters the MMP-9 intracellular distribution pattern. In contrast to MMP-9, TIMP-1 is detected as speckles. Intracellular TIMP-1 aggregation forms in the cytoplasmic area with IL-1β treatment. With H₂O₂ treatments, the cell morphology changes from cobbles to spindle shapes and the nuclei become larger with increases in TIMP-1 speckles in an H₂O₂ dose-dependent manner. Two TIMP-1 cell surface receptors, low density lipoprotein receptor-related protein-1 (LRP-1) and cluster of differentiation 82 (CD82), are expressed within the nucleus of MIO-M1 cells. Overall, these observations suggest that intracellular TIMP-1 is a target of proinflammatory and oxidative insults in the MGCs. Given the importance of the roles for MGCs in the retina, the functional implication of nuclear TIMP-1 and MMP-9 in MGCs is discussed.

Unravelling the Network of Nuclear Matrix Metalloproteinases for Targeted Drug Design

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that are responsible for the degradation of a wide range of extracellular matrix proteins, which are involved in many cellular processes to ensure the normal development of tissues and organs. Overexpression of MMPs has been observed to facilitate cellular growth, migration, and metastasis of tumor cells during cancer progression. A growing number of these proteins are being found to exist in the nuclei of both healthy and tumor cells, thus highlighting their localization as having a genuine purpose in cellular homeostasis. The mechanism underlying nuclear transport and the effects of MMP nuclear translocation have not yet been fully elucidated. To date, nuclear MMPs appear to have a unique impact on cellular apoptosis and gene regulation, which can have effects on immune response and tumor progression, and thus present themselves as potential therapeutic targets in certain types of cancer or disease. Herein, we highlight and evaluate what progress has been made in this area of research, which clearly has some value as a specific and unique way of targeting the activity of nuclear matrix metalloproteinases within various cell types.

Metallopeptidase inhibitor 1 (TIMP-1) promotes receptor tyrosine kinase c-Kit signaling in colorectal cancer

Colorectal cancer (CRC) is the third most prevalent cancer worldwide causing an estimated 700 000 deaths annually. Different types of treatment are available for patients with advanced metastatic colorectal cancer, including targeted biological agents, such as cetuximab, a monoclonal antibody that targets EGFR. We have previously reported a study indicating multiple levels of interaction between metallopeptidase inhibitor 1 (TIMP‐1) and the epidermal growth factor (EGF) signaling axis, which could explain how TIMP‐1 levels can affect the antitumor effects of EGFR inhibitors. We also reported an association between TIMP‐1‐mediated cell invasive behavior and KRAS status. To gain insight into the molecular mechanisms underlying the effects of TIMP‐1 in CRC, we examined by transcriptomics, proteomics, and kinase activity profiling a matched pair of isogenic human CRC isogenic DLD‐1 CRC cell clones, bearing either an hemizygous KRAS wild‐type allele or KRAS G13D mutant allele, exposed, or not, to TIMP‐1. Omics analysis of the two cell lines identified the receptor tyrosine kinase c‐Kit, a proto‐oncogene that can modulate cell proliferation and invasion in CRC, as a target for TIMP‐1. We found that exposure of DLD‐1 CRC cells to exogenously added TIMP‐1 promoted phosphorylation of c‐Kit, indicative of a stimulatory effect of TIMP‐1 on the c‐Kit signaling axis. In addition, TIMP‐1 inhibited c‐Kit shedding in CRC cells grown in the presence of exogenous TIMP‐1. Given the regulatory roles that c‐Kit plays in cell proliferation and migration, and the realization that c‐Kit is an important oncogene in CRC, it is likely that some of the biological effects of TIMP‐1 overexpression in CRC may be exerted through its effect on c‐Kit signaling.

Matrix Metalloproteinases in Renal Diseases: A Critical Appraisal

Matrix metalloproteinases (MMPs) are endopeptidases within the metzincin protein family that not only cleave extracellular matrix (ECM) components, but also process the non-ECM molecules, including various growth factors and their binding proteins. MMPs participate in cell to ECM interactions, and MMPs are known to be involved in cell proliferation mechanisms and most probably apoptosis. These proteinases are grouped into six classes: collagenases, gelatinases, stromelysins, matrilysins, membrane type MMPs, and other MMPs. Various mechanisms regulate the activity of MMPs, inhibition by tissue inhibitors of metalloproteinases being the most important. In the kidney, intrinsic glomerular cells and tubular epithelial cells synthesize several MMPs. The measurement of circulating MMPs can provide valuable information in patients with kidney diseases. They play an important role in many renal diseases, both acute and chronic. This review attempts to summarize the current knowledge of MMPs in the kidney and discusses recent data from patient and animal studies with reference to specific diseases. A better understanding of the MMPs' role in renal remodeling may open the way to new interventions favoring deleterious renal changes in a number of kidney diseases.

Tissue Inhibitor of Metalloproteinase-1 Promotes Polymorphonuclear Neutrophil (PMN) Pericellular Proteolysis by Anchoring Matrix Metalloproteinase-8 and -9 to PMN Surfaces

Matrix metalloproteinase (MMP)-8 and -9 released by degranulating polymorphonuclear cells (PMNs) promote pericellular proteolysis by binding to PMN surfaces in a catalytically active tissue inhibitor of metalloproteinases (TIMP)-resistant forms. The PMN receptor(s) to which MMP-8 and MMP-9 bind(s) is not known. Competitive binding experiments showed that Mmp-8 and Mmp-9 share binding sites on murine PMN surfaces. A novel form of TIMP-1 (an inhibitor of soluble MMPs) is rapidly expressed on PMN surfaces when human PMNs are activated. Membrane-bound TIMP-1 is the PMN receptor for pro- and active MMP-8 and -9 as shown by the following: 1) TIMP-1 is strikingly colocalized with MMP-8 and -9 on activated human PMN surfaces and in PMN extracellular traps; 2) minimal immunoreactive and active Mmp-8 or Mmp-9 are detected on the surface of activated Timp-1^-/- murine PMNs; and 3) binding of exogenous Timp-1 (but not Timp-2) to Timp-1^-/- murine PMNs reconstitutes the binding of exogenous pro-Mmp-8 and pro-Mmp-9 to the surface of Timp-1^-/- PMNs. Unlike full-length pro-Mmp-8 and pro-Mmp-9, mutant pro-Mmp proteins lacking the COOH-terminal hemopexin domain fail to bind to Mmp-8^-/-x Mmp-9^-/- murine PMNs. Soluble hemopexin inhibits the binding of pro-Mmp-8 and pro-Mmp-9 to Mmp-8^-/-x Mmp-9^-/- murine PMNs. Thus, the COOH-terminal hemopexin domains of pro-Mmp-8 and pro-Mmp-9 are required for their binding to membrane-bound Timp-1 on murine PMNs. Exposing nonhuman primates to cigarette smoke upregulates colocalized expression of TIMP-1 with MMP-8 and MMP-9 on peripheral blood PMN surfaces. By anchoring MMP-8 and MMP-9 to PMN surfaces, membrane-bound TIMP-1 plays a counterintuitive role in promoting PMN pericellular proteolysis occurring in chronic obstructive pulmonary disease and other diseases.

TIMP-1 and CD82, a promising combined evaluation marker for PDAC

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a widely secreted protein that regulates cell motility, proliferation, and apoptosis. Although it is recognized that TIMP-1-tetraspanin CD63 regulates epithelial cell apoptosis and proliferation, how TIMP-1 controls cell motility is not well understood. In this study, we identify tetraspanin CD82 (also called KAI1) as a component of the promiscuous TIMP-1 interacting protein complex on cell surface of human pancreatic adenocarcinoma cells. CD82 directly binds to TIMP-1 N-terminal region through its large extracellular loop and co-localizes with TIMP-1 in both cancer cell lines and clinical samples. Moreover, CD82 facilitates membrane-bound TIMP-1 endocytosis, which significantly contributes to the anti-migration effect of TIMP-1. CD82 silencing partially eliminates these functions. TIMP-1 and CD82 expression status in patients with pancreatic ductal adenocarcinoma (PDAC) might demonstrate future usefulness as a differentiation marker and give us new insight into tumorigenic metastatic potential.

Nuclear matrix metalloproteinase-2 in the cardiomyocyte and the ischemic-reperfused heart

Matrix metalloproteinases (MMPs) are zinc-dependent proteases involved in intra- and extra-cellular matrix remodeling resulting from oxidative stress injury to the heart. MMP-2 was the first MMP to be localized to the nucleus; however, its biological functions there are unclear. We hypothesized that MMP-2 is present in the nucleus under normal physiological conditions but increases during myocardial ischemia-reperfusion (I/R) injury-induced oxidative stress, proteolyzing nuclear structural proteins. Lamins are intermediate filament proteins that provide structural support to the nucleus and are putative targets of MMP-2. To identify lamin susceptibility to MMP-2 proteolysis, purified lamin A or B was incubated with MMP-2 in vitro. Lamin A, but not lamin B, was proteolysed by MMP-2 into an approximately 50kDa fragment, which was also predicted by in silico cleavage site analysis. Immunofluorescent confocal microscopy and subcellular fractionation showed MMP-2 both in the cytosol and nuclei of neonatal rat ventricular myocytes. Rat hearts were isolated and perfused by the Langendorff method aerobically, or subjected to I/R injury in the presence or absence of o-phenanthroline, an MMP inhibitor. Nuclear fractions extracted from I/R hearts showed increased MMP-2 activity, but not protein level. The level of troponin I, a known sarcomeric target of MMP-2, was rescued in I/R hearts treated with o-phenanthroline, demonstrating the efficacy of MMP inhibition. However, lamin A or B levels remained unchanged in I/R hearts. MMP-2 has a widespread subcellular distribution in cardiomyocytes, including a significant presence in the nucleus. The increase in nuclear MMP-2 activity seen during stunning injury here, indicates yet unknown biological actions, other than lamin proteolysis, which may require more severe ischemia to effect.

TIMP-1 Inhibits Apoptosis in Lung Adenocarcinoma Cells via Interaction with Bcl-2

Tissue inhibitors of metalloproteinases (TIMPs) are multifaceted molecules that exhibit properties beyond their classical proteinase inhibitory function. Although TIMP-1 is a known inhibitor of apoptosis in mammalian cells, the mechanisms by which it exerts its effects are not well-established. Our earlier studies using H2009 lung adenocarcinoma cells, implanted in the CNS, showed that TIMP-1 overexpressing H2009 cells (HB-1), resulted in more aggressive tumor kinetics and increased vasculature. The present study was undertaken to elucidate the role of TIMP-1 in the context of apoptosis, using the same lung cancer cell lines. Overexpressing TIMP-1 in a lung adenocarcinoma cell line H2009 resulted in an approximately 3-fold increased expression of Bcl-2, with a marked reduction in apoptosis upon staurosporine treatment. This was an MMP-independent function as a clone expressing TIMP-1 mutant T2G, lacking MMP inhibition activity, inhibited apoptosis as strongly as TIMP1 overexpressing clones, as determined by inhibition of PARP cleavage. Immunoprecipitation of Bcl-2 from cell lysates also co-immunoprecipitated TIMP-1, indicative of an interaction between these two proteins. This interaction was specific for TIMP-1 as TIMP-2 was not present in the Bcl-2 pull-down. Additionally, we show a co-dependency of TIMP-1 and Bcl-2 RNA and protein levels, such that abrogating Bcl-2 causes a downregulation of TIMP-1 but not TIMP-2. Finally, we demonstrate that TIMP-1 dependent inhibition of apoptosis occurs through p90RSK, with phosphorylation of the pro-apoptotic protein BAD at serine 112, ultimately reducing Bax levels and increasing mitochondrial permeability. Together, these studies define TIMP-1 as an important cancer biomarker and demonstrate the potential TIMP-1 as a crucial therapeutic target.

TIMP-1 overexpression in lung carcinoma enhances tumor kinetics and angiogenesis in brain metastasis

Tissue inhibitors of matrix metalloproteinase (TIMP) orchestrate many biologic activities, including inhibition of matrix metalloproteinase activity, activation of pro-matrix metalloproteinases, and regulation of cell proliferation, angiogenesis, and apoptosis induction. Tissue inhibitors of matrix metalloproteinase can play a protective role during tumor invasion and metastasis, but elevated TIMP messenger RNA levels have also been associated with aggressive cancers and poor clinical outcome. We examined the potential roles of TIMP-1 in H2009 lung adenocarcinoma cells and in cells transfected with a human TIMP-1-overexpressing vector (HB-6 and HB-1). Tumors resulting from the implantation of parental cell lines and transfected HB-1 cells into the brains of nude mice had a typical carcinoma profile, but human TIMP-1-overexpressing tumors showed enhanced tumor kinetics and focally more infiltrative features; vessel density assessed with anti-CD31 immunohistochemistry was also greater within HB-1 tumor implants. Similar effects on HB-6 and HB-1 cells versus parental cell lines and empty vector clones were observed in endothelial cell assays. Anchorage-independent growth and invasion through Matrigel were also increased in TIMP-1-overexpressing cells. Together, these results indicate tumor-promoting functions of TIMP-1 through alterations in angiogenesis, increased tumorigenicity, and invasive behavior. Although matrix metalloproteinase inhibition has been the traditionally identified function of TIMP-1, matrix metalloproteinase-independent interactions may contribute to the growth of metastatic carcinomas in the brain.

TIMP-1 inhibition of occludin degradation in Caco-2 intestinal cells: a potential protective role in necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC), a common intestinal disease affecting premature infants, is a major cause of morbidity and mortality. Previous reports indicate an upregulation of intestinal matrix metalloproteinases (MMPs) activity that may play key roles on the higher permeability of the intestinal barrier, typical to NEC. Recently, TIMP-1, a natural inhibitor of MMP's, was found to be over expressed in preterm human breast milk (HBM). Previous studies have shown that infants fed with HBM have a significant reduction in the incidence of NEC. The aim of the present study was to investigate the possible role that TIMP-1 may play on the maintenance of tight junctions and therefore the gut barrier integrity.

METHODS

Timp-1-treated Caco-2 intestinal cells were tested for MMP-2 enzymatic activity and cell junction integrity.

RESULTS

TIMP-1 inhibited MMP-2 activity, which induced a significant increase in the expression of occludin but not of claudin-4. TIMP-1 did not affect apoptosis.

CONCLUSION

One of the putative mechanisms associated with HBM protection against NEC is mediated by TIMP-1, which downregulates MMP-2 activity, inhibits the degradation of occluding, and preserves tight junctions and gut barrier integrity.

ERK2-regulated TIMP1 induces hyperproliferation of K-Ras(G12D)-transformed pancreatic ductal cells

Pancreatic ductal adenocarcinoma (PDAC) commonly contains a mutation in K-Ras(G12D) and is characterized by a desmoplastic reaction composed of deregulated, proliferating cells embedded in an abnormal extracellular matrix (ECM). Our previous observations imply that inhibiting the mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK2) kinase signal pathway reverses a matrix metalloproteinase 1-specific invasive phenotype. Here, we investigated the specific genes downstream of MAPK-ERK2 responsible for the hyperproliferative abilities of human and murine primary ductal epithelial cells (PDCs) within an ECM. Compared with control, DNA synthesis and total cell proliferation was significantly increased in human PDCs harboring the PDAC common p53, Rb/p16(INK4a), and K-Ras (G12D) mutations. Both of these effects were readily reversed following small-molecule inhibition or lentiviral silencing of ERK2. Microarray analysis of PDCs in three-dimensional (3D) culture revealed a unique, MAPK-influenced gene signature downstream of K-Ras (G12D). Unbiased hierarchical analysis permitted filtration of tissue inhibitor of matrix metalloproteinase 1 (TIMP1). Pancreatic cells isolated from Pdx1-Cre; LSL-K-ras(G12D/+)-mutated mice exhibit increased TIMP1 RNA transcription compared to wild-type littermate controls. Analyses of both 3D, in vitro human K-Ras (G12D) PDCs and data mining of publicly annotated human pancreatic data sets correlatively indicate increased levels of TIMP1 RNA. While silencing TIMP1 did not significantly effect PDC proliferation, exogenous addition of human recombinant TIMP1 significantly increased proliferation but only in transformed K-Ras (G12D) PDCs in 3D. Overall, TIMP1 is an upregulated gene product and a proliferative inducer of K-Ras(G12D)-mutated PDCs through the ERK2 signaling pathway.

SIRT1 redresses the imbalance of tissue inhibitor of matrix metalloproteinase-1 and matrix metalloproteinase-9 in the development of mouse emphysema and human COPD

Sirtuin1 (SIRT1), a protein/histone deacetylase, protects against the development of pulmonary emphysema. However, the molecular mechanisms underlying this observation remain elusive. The imbalance of tissue inhibitor of matrix metalloproteinases (TIMPs)/matrix metalloproteinases (MMPs) plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD)/emphysema. We hypothesized that SIRT1 protects against emphysema by redressing the imbalance between MMPs and TIMPs. To test this hypothesis, SIRT1-deficient and overexpressing/transgenic mice were exposed to cigarette smoke (CS). The protein level and activity of MMP-9 were increased in lungs of SIRT1-deficient mice exposed to CS compared with wild-type (WT) littermates, and these effects were attenuated by SIRT1 overexpression. SIRT1 deficiency decreased the level of TIMP-1, which was augmented in SIRT1 transgenic mice compared with WT littermates by CS. However, the level of MMP-2, MMP-12, TIMP-2, TIMP-3, or TIMP-4 was not altered by SIRT1 in response to CS exposure. SIRT1 reduction was associated with imbalance of TIMP-1 and MMP-9 in lungs of smokers and COPD patients. Mass spectrometry and immunoprecipitation analyses revealed that TIMP-1 acetylation on specific lysine residues was increased, whereas its interaction with SIRT1 and MMP-9 was reduced in mouse lungs with emphysema, as well as in lungs of smokers and COPD patients. SIRT1 deficiency increased CS-induced TIMP-1 acetylation, and these effects were attenuated by SIRT1 overexpression. These results suggest that SIRT1 protects against COPD/emphysema, in part, via redressing the TIMP-1/MMP-9 imbalance involving TIMP-1 deacetylation. Thus redressing the TIMP-1/MMP-9 imbalance by pharmacological activation of SIRT1 is an attractive approach in the intervention of COPD.

TIMP-1 increases expression and phosphorylation of proteins associated with drug resistance in breast cancer cells

Tissue inhibitor of metalloproteinase 1 (TIMP-1) is a protein with a potential biological role in drug resistance. To elucidate the unknown molecular mechanisms underlying the association between high TIMP-1 levels and increased chemotherapy resistance, we employed SILAC-based quantitative mass spectrometry to analyze global proteome and phosphoproteome differences of MCF-7 breast cancer cells expressing high or low levels of TIMP-1. In TIMP-1 high expressing cells, 312 proteins and 452 phosphorylation sites were up-regulated. Among these were the cancer drug targets topoisomerase 1, 2A, and 2B, which may explain the resistance phenotype to topoisomerase inhibitors that was observed in cells with high TIMP-1 levels. Pathway analysis showed an enrichment of proteins from functional categories such as apoptosis, cell cycle, DNA repair, transcription factors, drug targets and proteins associated with drug resistance or sensitivity, and drug transportation. The NetworKIN algorithm predicted the protein kinases CK2a, CDK1, PLK1, and ATM as likely candidates involved in the hyperphosphorylation of the topoisomerases. Up-regulation of protein and/or phosphorylation levels of topoisomerases in TIMP-1 high expressing cells may be part of the mechanisms by which TIMP-1 confers resistance to treatment with the widely used topoisomerase inhibitors in breast and colorectal cancer.

Tissue inhibitor of metalloproteinases-1 protects human neurons from staurosporine and HIV-1-induced apoptosis: mechanisms and relevance to HIV-1-associated dementia

HIV-1-associated dementia (HAD)-relevant proinflammatory cytokines robustly induce astrocyte tissue inhibitor of metalloproteinases-1 (TIMP-1). As TIMP-1 displays pleotropic functions, we hypothesized that TIMP-1 expression may serve as a neuroprotective response of astrocytes. Previously, we reported that chronically activated astrocytes fail to maintain elevated TIMP-1 expression, and TIMP-1 levels are lower in the brain of HAD patients; a phenomenon that may contribute to central nervous system pathogenesis. Further, the role of TIMP-1 as a neurotrophic factor is incompletely understood. In this study, we report that staurosporine (STS) and HIV-1(ADA) virus, both led to induction of apoptosis in cultured primary human neurons. Interestingly, cotreatment with TIMP-1 protects neurons from apoptosis and reverses neuronal morphological changes induced by these toxins. Further, the anti-apoptotic effect was not observed with TIMP-2 or -3, but was retained in a mutant of the N-terminal TIMP-1 protein with threonine-2 mutated to glycine (T2G) that is deficient in matrix metalloproteinase (MMP)-1, -2 and -3 inhibitory activity. Therefore, the mechanism is specific to TIMP-1 and partially independent of MMP-inhibition. Additionally, TIMP-1 modulates the Bcl-2 family of proteins and inhibits opening of mitochondrial permeability transition pores induced by HIV-1 or STS. Together, these findings describe a novel function, mechanism and direct role of TIMP-1 in neuroprotection, suggesting its therapeutic potential in HAD and possibly in other neurodegenerative diseases.

Tumor tissue inhibitor of metalloproteinases-1 (TIMP-1) in hormone-independent breast cancer might originate in stromal cells, and improves stratification of prognosis together with nodal status

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is shown to be a potential marker for poor prognosis in breast cancer, but the biology of TIMP-1 is only partially understood. In this study, TIMP-1 production was studied in a co-culture model of hormone-independent breast cancer cell lines and mesenchymal stem cells mimicking the stromal components of the tumor. In addition, the prognostic value of TIMP-1 was histologically evaluated in a clinical material of 168 patients with hormone-independent breast tumors. The hormone-independent breast cancer (BC) cell lines MDA-MB-231, M4A4 and NM2C5 did not produce TIMP-1 protein in measureable quantities. Six tested primary mesenchymal stem cell lines all produced TIMP-1. Co-culturing of mesenchymal stem cells and breast cancer cells resulted in positive immunocytochemical diffuse staining for TIMP-1 for both cell types. Culturing breast cancer cells with MSC-conditioned media resulted in a positive cytoplasmic immunoreactivity for TIMP-1, and TIMP-1 protein concentration in cell lysates increased 2.7-fold (range 1.1-4.7). The TIMP-1 mRNA levels remained unaffected in BC cells. This might suggest that breast cancer cells can take up TIMP-1 produced by stromal cells and are thus displaying cellular immunoreactivity. In addition, TIMP-1 was shown to improve stratification of prognosis in clinical material.

Overexpression of TIMP-1 in embryonic stem cells attenuates adverse cardiac remodeling following myocardial infarction

Transplanted embryonic stem (ES) cells, following myocardial infarction (MI), contribute to limited cardiac repair and regeneration with improved function. Therefore, novel strategies are still needed to understand the effects of genetically modified transplanted stem cells on cardiac remodeling. The present study evaluates whether transplanted mouse ES cells overexpressing TIMP-1, an antiapoptotic and antifibrotic protein, can enhance cardiac myocyte differentiation, inhibit native cardiac myocyte apoptosis, reduce fibrosis, and improve cardiac function in the infarcted myocardium. MI was produced in C57BL/6 mice by coronary artery ligation. TIMP-1-ES cells, ES cells, or culture medium (control) were transplanted into the peri-infarct region of the heart. Immunofluorescence, TUNEL staining, caspase-3 activity, ELISAs, histology, and echocardiography were used to identify newly differentiated cardiac myocytes and assess apoptosis, fibrosis, and heart function. Two weeks post-MI, significantly (p < 0.05) enhanced engraftment and cardiac myocyte differentiation was observed in TIMP-1-ES cell-transplanted hearts compared with hearts transplanted with ES cells and control. Hearts transplanted with TIMP-1-ES cells demonstrated a reduction in apoptosis as well as an increase (p< 0.05) in p-Akt activity compared with ES cells or culture media controls. Infarct size and interstitial and vascular fibrosis were significantly (p< 0.05) decreased in the TIMP-1-ES cell group compared to controls. Furthermore, MMP-9, a key profibrotic protein, was significantly (p < 0.01) reduced following TIMP-1-ES cell transplantation. Echocardiography data showed fractional shortening and ejection fraction were significantly (p< 0.05) improved in the TIMP-1-ES cell group compared with respective controls. Our data suggest that transplanted ES cells overexpressing TIMP-1 attenuate adverse myocardial remodeling and improve cardiac function compared with ES cells that may have therapeutic potential in regenerative medicine.

Nuclear localization of matrix metalloproteinases

Matrix metalloproteinases (MMPs) were originally identified as matrixin proteases that act in the extracellular matrix. Recent works have uncovered nontraditional roles for MMPs in the extracellular space as well as in the cytosol and nucleus. There is strong evidence that subspecialized and compartmentalized matrixins participate in many physiological and pathological cellular processes, in which they can act as both degradative and regulatory proteases. In this review, we discuss the transcriptional and translational control of matrixin expression, their regulation of intracellular sorting, and the structural basis of activation and inhibition. In particular, we highlight the emerging roles of various matrixin forms in diseases. The activity of matrix metalloproteinases is regulated at several levels, including enzyme activation, inhibition, complex formation and compartmentalization. Most MMPs are secreted and have their function in the extracellular environment. MMPs are also found inside cells, both in the nucleus, cytosol and organelles. The role of intracellular located MMPs is still poorly understood, although recent studies have unraveled some of their functions. The localization, activation and activity of MMPs are regulated by their interactions with other proteins, proteoglycan core proteins and / or their glycosaminoglycan chains, as well as other molecules. Complexes formed between MMPs and various molecules may also include interactions with noncatalytic sites. Such exosites are regions involved in substrate processing, localized outside the active site, and are potential binding sites of specific MMP inhibitors. Knowledge about regulation of MMP activity is essential for understanding various physiological processes and pathogenesis of diseases, as well as for the development of new MMP targeting drugs.

Silencing tissue inhibitors of metalloproteinases (TIMPs) with short interfering RNA reveals a role for TIMP-1 in hepatic stellate cell proliferation

Myofibroblastic, activated hepatic stellate cells (HSC) play a pivotal role in the development of liver fibrosis through the secretion of fibrillar collagens and the tissue inhibitors of metalloproteinase (TIMP)-1 and -2. TIMPs are believed to promote hepatic fibrosis by inhibiting both matrix degradation and apoptosis of HSC. In other cell types, there is evidence that TIMP-1 has effects on proliferation, however the role of TIMPs in the regulation of HSC proliferation remains unexplored. Therefore, we have used short interfering RNA (siRNA) to investigate the effects of autocrine TIMP-1 and -2 on HSC proliferation. TIMP-1 and -2 siRNA were highly effective, producing peak target protein knockdown compared to negative control siRNA of 92% and 63%, respectively. Specific silencing of TIMP-1, using siRNA, significantly reduced HSC proliferation. TIMP-1 was localised in part to the HSC nucleus and TIMP-1 siRNA resulted in loss of both cytoplasmic and nuclear TIMP-1. Attenuated proliferation was associated with reduced Akt phosphorylation and was partially rescued by addition of recombinant TIMP-1. We have revealed a novel autocrine mitogenic effect of TIMP-1 on HSC, which may involve Akt-dependent and specific nuclear mechanisms of action. We suggest that TIMP-1 might promote liver fibrosis by means other than its previously described anti-apoptotic effect on HSC. Moreover, these findings, together with our previous reports and the emerging data from in vivo studies of TIMP inhibition, provide strong evidence that TIMP-1 is mechanistically central to liver fibrosis and an important potential therapeutic target.

Neutralizing TIMP1 restores fecundity in a rat model of endometriosis and treating control rats with TIMP1 causes anomalies in ovarian function and embryo development

Human and rat endometriotic lesions synthesize and secrete tissue inhibitor of metalloproteinase 1 (TIMP1). More TIMP1 localizes in the ovarian theca in an established rat model for endometriosis (Endo) when compared to surgical controls (Sham). We hypothesized that endometriotic TIMP1 secreted into peritoneal fluid (PF) negatively affects ovarian function and embryogenesis by altering the balance of matrix metalloproteinases (MMPs) and TIMPs. Three experiments were performed modulating TIMP1 in vitro and in vivo to investigate ovarian and embryonic anomalies. The first experiment demonstrated control embryos treated in vitro with endometriotic PF concentrations of TIMP1 developed abnormally. In the second experiment where TIMP1 was modulated in vivo, TIMP1-treated Sham rats had fewer zygotes, ovarian follicles, and corpora lutea (CLs) and poorer embryo quality and development, which is analogous to the findings in Endo rats. Importantly, Endo rats treated with a TIMP1 function-blocking antibody had zygote, follicle, and CL numbers and embryo quality similar to Sham rats. In addition, more TIMP1 inhibitory activity was found in ovaries from Endo and TIMP1-treated Sham rats than in ovaries from Sham or TIMP1 antibody-treated Endo rats. In experiment three, control rats (no surgery) treated with Endo PF had fewer follicles and CLs and increased TIMP1 localization in the ovarian theca whereas treatment with Endo PF stripped of TIMP1 or with Sham PF had no effect, providing further evidence that endometriotic TIMP1 sequesters in the ovary and inhibits MMPs necessary for ovulation. Collectively, these results showed that excessive TIMP1 was deleterious to ovulation and embryo development. Thus, novel TIMP1-modulating therapies may be developed to alleviate infertility in women with endometriosis.

Glomerular matrix metalloproteinases and their regulators in the pathogenesis of lupus nephritis

Lupus nephritis is a major contributor to morbidity and mortality in systemic lupus erythematosus, but little is known about the pathogenic processes that underlie the progressive decay in renal function. A common finding in lupus nephritis is thickening of glomerular basement membranes associated with immune complex deposition. It has been speculated that alterations in the synthesis or degradation of membrane components might contribute to such changes, and thereby to initiation and progression of nephritis through facilitation of immune complex deposition. Matrix metalloproteinases (MMPs) are enzymes that are intimately involved in the turnover of major glomerular basement membrane constituents, including collagen IV and laminins. Alterations in the expression and activity of MMPs have been described in a number of renal diseases, suggesting their relevance to the pathogenesis of various glomerulopathies. The same is true for their natural inhibitors, the tissue inhibitor of metalloproteinase family. Recent data from our group have identified an increase in proteolytic activity within the glomerulus coinciding with the development of proteinuria in the mouse model of systemic lupus erythematosus. (NXB x NZW)F1 Here we review current understanding of MMP/tissue inhibitor of metalloproteinase function within the kidney, and discuss their possible involvement in the development and progression of lupus nephritis.

TIMP-1 binding to proMMP-9/CD44 complex localized at the cell surface promotes erythroid cell survival

Besides its ability to inhibit MMP activity, TIMP-1 exhibits other biological functions. We earlier reported that TIMP-1 induced UT-7 erythroid cell survival through activation of the JAK2/PI 3-kinase/Akt pathway and we now aim to determine whether the TIMP-1 anti-apoptotic effect requires MMP involvement. We first show that proMMP-9 was expressed in UT-7 cells and associated with the cell plasma membrane. Such proMMP-9 localization was crucial for TIMP-1 intracellular signalling since (i) TIMP-1 specifically bound to proMMP-9 and (ii) proMMP-9 silencing abrogated the TIMP-1 effect. We also demonstrated that TIMP-1 anti-apoptotic effect was independent on MMP inhibition since MMP-9 function blocking antibodies as well as a synthetic MMP inhibitor were unable to reproduce TIMP-1 effect. Nevertheless, these compounds prevented TIMP-1 binding to proMMP-9 and subsequently abolished TIMP-1-induced cell survival. We finally demonstrated that CD44 anchored proMMP-9 to the plasma membrane and enabled TIMP-1-mediated signal transduction. Therefore, our results indicate that the anti-apoptotic signalling of TIMP-1 depends on the formation of a ternary complex between TIMP-1, proMMP-9 and CD44 at the UT-7 erythroid cell surface.

Biology and potential clinical implications of tissue inhibitor of metalloproteinases-1 in colorectal cancer treatment

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the industrialized world. About half of "curatively" resected patients develop recurrent disease within the next 3-5 years despite the lack of clinical, histological and biochemical evidence of remaining overt disease after resection of the primary tumour. Availability of validated biological markers for early detection, selection for adjuvant therapy, prediction of treatment efficacy and monitoring of treatment efficacy would most probably increase survival. Tissue inhibitor of metalloproteinases-1 (TIMP-1) may be such a marker. TIMP-1 inhibits the proteolytic activity of metalloproteinases, which are centrally involved in tumour invasion and metastases. However, in clinical investigations high tumour tissue or plasma levels of TIMP-1 have shown a strong and independent association with a shorter survival time in CRC patients, suggesting that TIMP-1 could have a tumour-promoting function. Furthermore, measurement of plasma TIMP-1 has been shown to be useful for disease detection, with a high sensitivity and high specificity for early-stage colon cancer. This review describes some basic information on the current knowledge of the biology of TIMP-1 as well as the potential use of TIMP-1 as a biological marker in the management of CRC patients.

TIMP-1 promotes age-related renal fibrosis through upregulating ICAM-1 in human TIMP-1 transgenic mice

Imbalance of matrix metalloproteinases and tissue inhibitors of metalloproteinases (MMPs/TIMPs) takes part in age-related renal fibrosis; so does molecular inflammation. As several inflammatory mediators including intercellular adhesion molecule-1 (ICAM-1) are substrates of MMPs, we speculated that TIMP-1 might affect ICAM-1 through MMPs and subsequently promote age-related renal fibrosis. Then, we observed changes of kidney in human TIMP-1 transgenic mice and wild-type mice of different ages. It was found that the expressions and activities of gelatinases were downregulated; the expressions of ICAM-1, collagen III, collagen IV, and transforming growth factor (TGF)-beta1 were upregulated; and the number of infiltrating macrophages was increased in kidneys of 24-month-old TIMP-1 transgenic mice with high expressions of TIMP-1, compared with wild-type mice. Our results indicated that TIMP-1 could promote age-related renal fibrosis, which was partly attributed to enhancing inflammation through upregulation of ICAM-1.

TIMP-1 regulates cell proliferation by interacting with the ninth zinc finger domain of PLZF

The tissue inhibitors of metalloproteinases (TIMPs) are multifunctional proteins that specifically inhibit matrix metalloproteinases (MMPs) and regulate extracellular matrix (ECM) turnover and tissue remodeling. This is directed by forming tightly bound inhibitory complexes with MMPs. Recent years have revealed important differences of various biological activities between TIMP families but molecular mechanisms are not clear. To define the molecular mechanisms of TIMP-1-dependent biological processes, we used TIMP-1 as bait in a yeast two-hybrid screen, along with a human ovary cDNA library. Further characterization revealed the ninth zinc finger domain as an interacting domain of the promyelocytic leukemia zinc finger protein (PLZF). Interaction of PLZF with TIMP-1 in mammalian cells was also confirmed by co-immunoprecipitation and with in vitro binding assays. We investigated whether TIMP-1-mediated anti-apoptotic activity could promote the growth of ovarian cancer in an experimental model system. TIMP-1 treatment was found to be more effective at increasing ovarian cancer growth when compared with PLZF in parallel experiments. Subsequently, the efficacy of a combined treatment with TIMP-1 and PLZF was investigated. In the presence of both of these proteins, TIMP-1 significantly reduced apoptosis induced by PLZF in cervical carcinoma cells. These combined results indicate that TIMP-1 functions as an anti-activator of the transcriptional repressive activity of PLZF.

Signal transducers and activators of transcription-3 up-regulates tissue inhibitor of metalloproteinase-1 expression and decreases invasiveness of breast cancer

Signal transducers and activators of transcription (STAT)-3 is an oncogenic protein that is constitutively activated in many human cancers, including 30 to 60% of primary breast cancer. The biological significance of STAT3 activation in breast cancer is not fully understood. We have previously shown that STAT3 up-regulates tissue inhibitors of metalloproteinase (TIMP)-1, a cytokine known to block metalloproteinases and decrease invasiveness in certain cancer cell types. We hypothesize that STAT3 activation may modulate tumor invasiveness of breast cancer by regulating TIMP1 expression. Using MCF-7 cells transfected with tetracycline-off STAT3C (constitutively active STAT3), we generated an in vitro system in which STAT3C levels can be tightly controlled in breast cancer cells. Increasing tetracycline levels gradually decreased STAT3C and TIMP1 in a dose-dependent manner, and down-regulation of these proteins led to a reciprocal decrease in invasiveness of these cells in Matrigel. Addition of a neutralizing anti-TIMP1 antibody increased invasiveness in the same experimental system. Using immunohistochemistry and 142 primary breast tumors, we found a significant association between the expression of the phosphorylated/active form of STAT3 (pSTAT3) and that of TIMP1. Importantly, STAT3 activation correlated significantly with a lower frequency of vascular and lymphatic invasion (P = 0.015 and P = 0.0002, respectively). Our data support the concept that STAT3 activation significantly modulates the biological and clinical behavior of breast cancer.

Novel functions of TIMPs in cell signaling

Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of matrix metalloproteinases (MMPs) and the balance between MMPs/TIMPs regulates the extracellular matrix (ECM) turnover and remodeling during normal development and pathogenesis. Increasing evidence indicates a much more complex role for TIMPs during tumor progression and angiogenesis, in addition to their regulation of MMP-mediated ECM degradation. In this article, we review both the MMP-dependent and -independent actions of TIMPs for the regulation of cell death, cell proliferation, and angiogenesis, with a particular emphasis on TIMP-1 in the regulation of tetraspanin/integrin-mediated cell survival signal transduction pathways.

Clinicopathologic implications of tissue inhibitor of metalloproteinase-1-positive diffuse large B-cell lymphoma

The tissue inhibitor of metalloproteinase-1 (TIMP-1) is a stromal factor that promotes plasmablastic differentiation, and the survival of germinal center B-cells. The expression of TIMP-1 is known to be correlated with a subset of non-Hodgkin lymphoma at the mRNA level, and Epstein-Barr virus infection in vitro. To characterize TIMP-1(+) diffuse large B-cell lymphoma, TIMP-1 expression was investigated in tissue microarrays from 182 cases of de novo diffuse large B-cell lymphoma and compared with prognostic factors, immunophenotypes, and Epstein-Barr virus infection status. TIMP-1 was expressed not only in tumor cells themselves, in 14 of 182 cases (8%), designated as TIMP-1(+) diffuse large B-cell lymphoma, but also in stromal cells like fibroblasts and endothelial cells. In univariate analysis and hierarchical clustering, our findings suggest that TIMP-1 expression may represent a distinct subgroup. In multivariate analysis, TIMP-1(+) diffuse large B-cell lymphoma (n=14) was associated with unfavorable outcomes compared to TIMP-1(-) diffuse large B-cell lymphoma (n=168) (odds ratio=2.5, P=0.049). Together with TIMP-1 expression, age (greater than 60 years), the presence of B-symptoms, abnormal lactate dehydrogenase level, or more advanced stage (III/IV) was correlated with a poor overall survival. However, TIMP-1 expression in diffuse large B-cell lymphoma was not correlated with other prognostic factors including: clinical stage, international prognostic index score, and nongerminal center B-cell phenotype, as well as Epstein-Barr virus infection. Our results suggest that TIMP-1 expression may be an independent negative prognostic factor in patients with diffuse large B-cell lymphoma.

Tissue inhibitor of metalloproteinase-2 promotes neuronal differentiation by acting as an anti-mitogenic signal

Although traditionally recognized for maintaining extracellular matrix integrity during morphogenesis, the function of matrix metallo-proteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), in the mature nervous system is essentially unknown. Here, we report that TIMP-2 induces pheochromocytoma PC12 cell-cycle arrest via regulation of cell-cycle regulatory proteins, resulting in differentiation and neurite outgrowth. TIMP-2 decreases cyclins B and D expression and increases p21Cip expression. Furthermore, TIMP-2 promotes cell differentiation via activation of the cAMP/Rap1/ERK (extracellular signal-regulated kinase) pathway. Expression of dominant-negative Rap1 blocks TIMP-2-mediated neurite outgrowth. Both the cell-cycle arrest and neurite outgrowth induced by TIMP-2 was independent of MMP inhibitory activity. Consistent with the PC12 cell data, primary cultures of TIMP-2 knock-out cerebral cortical neurons exhibit significantly reduced neurite length, which is rescued by TIMP-2. These in vitro results were corroborated in vivo. TIMP-2 deletion causes a delay in neuronal differentiation, as demonstrated by the persistence of nestin-positive progenitors in the neocortical ventricular zone. The interaction of TIMP-2 with alpha3beta1 integrin in the cerebral cortex suggests that TIMP-2 promotes neuronal differentiation and maintains mitotic quiescence in an MMP-independent manner through integrin activation. The identification of molecules responsible for neuronal quiescence has significant implications for the ability of the adult brain to generate new neurons in response to injury and neurological disorders, such as Alzheimer's and Parkinson's diseases.

Differential regulation of TIMP-1, -2, and -3 mRNA and protein expressions during mouse incisor development

Tissue inhibitors of metalloproteinases (TIMPs) possess multiple functions, in addition to their matrix metalloproteinase (MMP) inhibitory activity. The continuously growing incisor of mouse possesses a stem cell compartment at the apical end of the epithelium (the apical loop) and thus provides an excellent tool to analyze the mechanisms of organogenesis and cytodifferentiation. To understand the functions of TIMPs in tooth development, we have analyzed the gene expression and protein localization of TIMP-1, -2, and -3 during mouse incisor development, from embryonic day 13 (E13) to postnatal day 3 (P3). TIMP-1 was present on the basement membrane during early developmental stages. At P2, TIMP-1 was strongly detected along the apical loop, transiently disappeared from the basement membrane in the cytodifferentiation zone, and later reappeared at the distal end of functional ameloblasts. Expression of TIMP-2 protein was restricted to the outer part of the apical loop throughout the examined stages. At P2, TIMP-2 was present on the basement membrane at the outer part of the apical loop. The dental follicle also expressed Timp-2, and the corresponding protein was abundant within the extracellular matrix. Timp-3 mRNA was highly expressed in the mesenchyme surrounding the apical loop. During matrix formation, Timp-3 was expressed by subodontoblasts, and the protein was detected in this layer and between odontoblasts. Distinct temporal and spatial expression patterns of TIMPs suggest divergent functions of these factors in incisor organogenesis.

Beneficial and detrimental influences of tissue inhibitor of metalloproteinase-1 (TIMP-1) in tumor progression

Tissue inhibitor of metalloproteinase-1 (TIMP-1) is one representative of the natural matrix metalloproteinase (MMP) inhibitor family, encompassing four members. It inhibits all MMPs, except several MT-MMPs, and a disintegrin with a metalloproteinase domain (ADAM)-10 with Kis < nM. Unexpectedly, its upregulation was associated to poor clinical outcome for several cancer varieties. Such finding might be related to the growth-promoting and survival activities of TIMP-1 for normal and cancer cells. In most cases, such properties are MMP-independent and binding of TIMP-1 to an unknown receptor system can trigger JAK (or FAK)/PI3 kinase/Akt/bad-bclX2 (erythroid, myeloid, epithelial cell lines) or Ras/Raf1/FAK (osteosarcoma cell line) signaling pathways. The relationship between viral infection and TIMP-1 expression is here underlined. Thus, TIMP-1 might display a dual influence on tumor progression; either beneficial by inhibiting MMPs as MMP-9 and by impairing angiogenesis or detrimental by favoring cancer cells growth or survival. We consider that the proMMP-9/TIMP-1 balance is of critical importance in early events of tumor progression, and might show promise as diagnostic and prognostic marker of malignancy.

Differential expression of matrix metalloproteinases and interleukin-8 during regeneration of human airway epithelium in vivo

In many airway diseases, the airway epithelium is severely damaged and has to regenerate rapidly to restore its function. The regeneration process involves chronological steps of epithelial cell migration, proliferation, stratification, and differentiation. The present study has used an in vivo humanized airway xenograft model in nude mice that mimics the regeneration dynamics of human airway epithelium after severe injury, and human-specific molecular tools, to study the expression profiles of epithelial matrix metalloproteinases (MMPs)-7 and -9, of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), and of the pro-inflammatory cytokine interleukin-8 (IL-8) during the different steps of human airway epithelium regeneration. It was found that during the cell migration and proliferation steps, airway epithelial cells expressed IL-8 at a high level, whereas airway epithelial pseudo-stratification and surface airway epithelial differentiation were associated with increased expression of MMPs and a progressive decrease in IL-8. Interestingly, immunohistochemical analysis revealed exclusive expression of MMPs at the apical part of the well-differentiated regenerated airway epithelium, and incubation of the regenerating epithelial cells with MMP inhibitors led to abnormal epithelial differentiation. These data provide new insight into the temporal expression of MMPs and IL-8 during the regeneration of airway epithelium and demonstrate the involvement of these factors during the different steps that lead to restoration of a well-differentiated and functional airway epithelium.

Gelatinase-mediated migration and invasion of cancer cells

The matrix metalloproteinases(MMP)-2 and -9, also known as the gelatinases have been long recognized as major contributors to the proteolytic degradation of extracellular matrix during tumor invasion. In the recent years, a plethora of non-matrix proteins have also been identified as gelatinase substrates thus significantly broadening our understanding of these enzymes as proteolytic executors and regulators in various physiological and pathological states including embryonic growth and development, angiogenesis and tumor progression, inflammation, infective diseases, degenerative diseases of the brain and vascular diseases. Although the effect of broad-spectrum inhibitors of MMPs in the treatment of cancer has been disappointing in clinical trials, novel mechanisms of gelatinase inhibition have been now identified. Inhibition of the association of the gelatinases with cell-surface integrins appears to offer highly specific means to target these enzymes without inhibiting their catalytic activity in multiple cell types including endothelial cells, tumor cells and leukocytes. Here, we review the multiple functions of the gelatinases in cancer, and especially their role in the tumor cell migration and invasion.

Induction by IL-1β of Tissue Inhibitor of Metalloproteinase-1 in Human Orbital Fibroblasts: Modulation of Gene Promoter Activity by IL-4 and IFN-γ

Thyroid-associated ophthalmopathy (TAO), an autoimmune component of Graves' disease, is associated with profound connective tissue remodeling and fibrosis that appear to involve the selective activation of orbital fibroblasts. Accumulation of extracellular matrix molecules is a hallmark of this process. Here we report that orbital fibroblasts treated with IL-1beta express high levels of tissue inhibitor of metalloproteinase-1 (TIMP-1), an important modulator of matrix metalloproteinase activity. These high levels are associated with increased TIMP-1 activity. The induction is mediated at the pretranslational level and involves activating the TIMP-1 gene promoter. IL-1beta activates the ERK 1/2 pathway in these fibroblasts and interrupting this signaling either with PD98059, a chemical inhibitor of MEK, or by transfecting cells with a dominant negative ERK 1 plasmid results in the attenuation of TIMP-1 induction. Surprisingly, treatment with IL-4 or IFN-gamma could also block the IL-1beta induction by attenuating TIMP-1 gene promoter activity. These findings suggest that TIMP-1 expression in orbital fibroblasts following activation with IL-1beta could represent an important therapeutic target for modifying the proteolytic environment. This might alter the natural course of tissue remodeling in TAO.

Multiple roles of matrix metalloproteinases during apoptosis

Structural, molecular and biochemical approaches have contributed to piecing together the puzzle of how matrix metalloproteinases (MMPs) work and contribute to various disease processes. However, MMPs have many unexpected substrates other than components of the extracellular matrix which profoundly influence cell behaviour, survival and death. With the current understanding of diverse/novel roles of matrix metalloproteinases--particularly their direct or indirect relevance for the early steps during programmed cell death--some seemingly contrasting results seem less surprising. To better target MMPs an appreciation of their many extracellular, intracellular and intranuclear functions, often acting in opposing directions with paradoxical roles in cell death, is carefully required.

Tissue inhibitor of matrix metalloproteinase-1 overexpression in M1 myeloblasts impairs IL-6-induced differentiation

The balance between matrix metalloproteinase (MMP) and tissue inhibitor of matrix metalloproteinase (TIMP) is important for extracellular matrix interactions of hematopoietic cells. MMP-independent growth modulating activity for TIMP-1 on B lymphocytes and erythroid progenitors has also been described, but a role for TIMP-1 in myelomonocytic differentiation has not been previously reported. In this study, we demonstrate that TIMP-1 overexpression impairs differentiation of the myeloblastic M1 cell line following interleukin (IL)-6 stimulation. We generated retroviral vectors coexpressing human TIMP-1 and the green fluorescent protein (GFP) and stably transduced murine M1 myeloid cells. TIMP-1 expressing cells showed a large reduction in IL-6-induced macrophage differentiation in vitro that was reversible with a specific monoclonal antibody. The differentiation delay in M1/TIMP-1 cells was also specifically reversible by pharmacologic phosphatidylinositol-3 kinase (PI3-K) inhibition. Additionally, overexpression of a TIMP-1/GFP fusion protein also impaired M1 differentiation and this protein was localized to the cell surface, consistent with an autocrine receptor-mediated mechanism. Surprisingly, TIMP-1 transduced cells had a selective advantage for growth in IL-6, indicating that functional effects on growth and differentiation of M1 cells were primarily through an autocrine mechanism. Intrinsic TIMP-1 expression in myeloid leukemia cells might thus impact upon survival or differentiation.

Effect of interleukin-10 and platelet-derived growth factor on expressions of matrix metalloproteinases-2 and tissue inhibitor of metalloproteinases-1 in rat fibrotic liver and cultured hepatic stellate cells

AIM

To examine the expressions of matrix metalloproteinases-2 (MMP-2) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in rat fibrotic liver and in normal rat hepatic stellate cells, and to investigate the changes in their expressions in response to treatment with interleukin-10 (IL-10) and platelet-derived growth factor (PDGF).

METHODS

Rat models of CCl4-induced hepatic fibrosis were established and the liver tissues were sampled from the rats with or without IL-10 treatment, and also from the control rats. The expressions of MMP-2 and TIMP-1 in liver tissues were detected by S-P immunohistochemistry, and their expression intensities were evaluated in different groups. Hepatic stellate cells (HSCs) were isolated from normal rat and cultured in vitro prior to exposure to PDGF treatment or co-treatment with IL-10 and PDGF. MMP-2 and TIMP-1 levels were measured by semi-quantitative reverse transcriptional polymerase chain reaction (RT-PCR).

RESULTS

CCl4- induced rat hepatic fibrosis models were successfully established. The positive expressions of MMP-2 and TIMP-1 increased obviously with the development of hepatic fibrosis, especially in untreated model group (84.0% and 92.0%, P<0.01). The positive signals decreased significantly following IL-10 treatment (39.3% and 71.4%, P<0.01 and P<0.05) in a time-dependent manner. TIMP-1 mRNA in PDGF-treated group was significantly increased time-dependently in comparison with that of the control group, but PDGF did not obviously affect MMP-2 expression. No difference was noted in TIMP-1 and MMP-2 expressions in HSCs after IL-10 and PDGF treatment (P>0.05).

CONCLUSION

MMP-2 and TIMP-1 expressions increase in liver tissues with the development of fibrosis, which can be inhibited by exogenous IL-10 inhibitor. PDGF induces the up-regulation of TIMP-1 but not MMP-2 in the HSCs. IL-10 inhibits TIMP-1 and MMP-2 expressions in HSCs induced by PDGF.

TIMP-1 alters susceptibility to carcinogenesis

Tissue inhibitors of metalloproteinases (TIMPs) are a family of multifunctional proteins known to possess a broad range of biological activities, including inhibition of metalloproteinase activity, regulation of proliferation and apoptosis of a variety of cell types, and, depending on the context, differential regulation of angiogenic and inflammatory responses. Elevated mRNA expression of TIMP family members correlates with malignancy and clinical outcome in many human cancer types; however, a protective role for TIMPs also has been observed in various mouse models of human cancer. In the current study, we found distinct spatial-temporal expression patterns for the mRNA of TIMP family members in a mouse model of epithelial carcinogenesis [i.e., keratin 14-human papillomavirus 16 (K14-HPV16) transgenic mice]. To test the hypothesis that elevated expression of TIMP-1 functionally regulates epithelial carcinogenesis, we introduced a human TIMP-1 transgene into K14-HPV16 transgenic mice and assessed neoplastic progression. Results from these studies suggest that TIMP-1 enhances tumorgenicity by potentiating keratinocyte hyperproliferation and appearance of chromosomal aberrations in premalignant cells, thereby increasing their risk to undergo malignant conversion. In addition, TIMP-1 inhibits tissue gelatinolytic activity in tumor stroma, affects stabilization of collagen fibrils, but does not inhibit malignant conversion of dysplasias into carcinomas or development of metastases. The combined implications of these studies suggest that TIMP-1 is an important contributor to epithelial neoplastic progression and supports the concept that TIMP-1 exerts differential regulation on tissues in a stage-dependent manner.

Tumor Tissue Levels of Tissue Inhibitor of Metalloproteinase-1 as a Prognostic Marker in Primary Breast Cancer

PURPOSE

In the present study, we investigated the association between tumor tissue levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and prognosis in patients with primary breast cancer and analyzed whether TIMP-1 may be useful as a prognostic marker in combination with urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1).

EXPERIMENTAL DESIGN

In cytosolic extracts of 2984 primary breast tumors, total levels of TIMP-1 were determined using an established, validated ELISA. Levels of uPA and PAI-1 have previously been determined in the extracts.

RESULTS

Univariate survival analysis showed a significant relationship between higher levels of TIMP-1 (continuous log-transformed variable) and poor prognosis [recurrence-free survival (RFS), overall survival (OS); P < 0.001]. Performing isotonic regression analysis, we identified a cut point to classify tumors as TIMP-1-low or TIMP-1-high. Using this cut point, high levels of TIMP-1 were significantly associated with shorter survival in univariate analysis, both in the total patient group (RFS, OS; P < 0.001), in the node-negative subgroup (RFS, hazard ratio = 1.28, P = 0.006), and in the node-positive subgroup (RFS, hazard ratio = 1.43, P < 0.001). In multivariate analysis, including uPA and PAI-1, TIMP-1 was significantly associated with shorter RFS, both when included as a continuous log-transformed (P = 0.03) and as a dichotomized variable (P = 0.002).

CONCLUSIONS

This study validates previous findings that tumor tissue levels of TIMP-1 are associated with prognosis in patients with primary breast cancer. It confirms that TIMP-1 may be useful as a prognostic marker in combination with uPA/PAI-1 and adds substantial positive information on the use of TIMP-1 as a prognostic marker in breast cancer.

The TIMPs tango with MMPs and more in the central nervous system

The matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular proteases that have been implicated in CNS development and disease. Crucial homeostatic regulation of MMPs is mediated through the expression and actions of the tissue inhibitors of metalloproteinases (TIMPs). Although the TIMPs are recognized inhibitors of the MMPs, recent studies have revealed that these proteins also can exhibit biological activities that are distinct from their interactions with or inhibition of the MMPs. With our understanding of the roles of the TIMPs in the CNS continuously emerging, this review examines the current state of knowledge regarding the multifarious and novel functions of this family of proteins, with particular attention to their increasing potential in the development, plasticity, and pathology of the CNS.

Matrix metalloproteinase-2 (MMP-2) is present in the nucleus of cardiac myocytes and is capable of cleaving poly (ADP-ribose) polymerase (PARP) in vitro

Matrix metalloproteinases (MMPs) are traditionally known for their role in extracellular matrix remodeling. Increasing evidence reveals several alternative substrates and novel biological roles for these proteases. Recent evidence showed the intracellular localization of MMP-2 within cardiac myocytes, colocalized with troponin I within myofilaments. Here we investigated the presence of MMP-2 in the nucleus of cardiac myocytes using both immunogold electron microscopy and biochemical assays with nuclear extracts. The gelatinase activity found in both human heart and rat liver nuclear extracts was blocked with MMP inhibitors. In addition, the ability of MMP-2 to cleave poly (ADP-ribose) polymerase (PARP) as a substrate was examined as a possible role for MMP-2 in the nucleus. PARP is a nuclear matrix enzyme involved in the repair of DNA strand breaks, which is known to be inactivated by proteolytic cleavage. PARP was susceptible to cleavage by MMP-2 in vitro in a concentration-dependent manner, yielding novel degradation products of ~66 and <45 kDa. The cleavage of PARP by MMP-2 was also blocked by MMP inhibitors. This is the first characterization of MMP-2 within the nucleus and we hereby suggest its possible role in PARP degradation.

Tissue inhibitor of metalloproteinase (TIMP)-1: the TIMPed balance of matrix metalloproteinases in the central nervous system

Astrocytes are intimately involved in the mechanisms of neural injury and repair. They participate in a variety of homeostatic functions and elicit repair responses as balance mechanisms. Currently, there is a growing appreciation of a more active role of astrocytes in neuronal signaling and function. One key homeostatic mechanism of astrocytes in tissue repair is maintained through their production of tissue inhibitors of metalloproteinases (TIMPs). The family of TIMPs (1-4) plays a central regulatory role as inhibitors of matrix metalloproteinases (MMPs), enzymes involved in extracellular matrix maintenance and remodeling. Recently, TIMP-1, the inducible form, has been identified as a multifunctional molecule with divergent functions. It participates in wound healing and regeneration, cell morphology and survival, tumor metastasis, angiogenesis, and inflammatory responses. An imbalance of MMP/TIMP regulation has been implicated in several inflammatory diseases of the central nervous system (CNS). Here we review the conundrums of TIMP-1 regulation in CNS pathophysiology. We propose that astrocyte-TIMP-1 may play an important role in CNS homeostasis and disease. Astrocyte TIMP-1 expression is differentially regulated in inflammatory neurodegenerative diseases and may have significant therapeutic relevance.

S100A4 regulates membrane induced activation of matrix metalloproteinase-2 in osteosarcoma cells

To study the role of the metastasis associated protein S100A4, an osteosarcoma cell line (OHS) with a high level of this protein was transfected with a vector containing a ribozyme that degrades S100A4 mRNA and, as controls, OHS cells were transfected with the vector alone. We have followed up our previous investigation (Bjørnland et al. 1999) by a detailed investigation of these cell lines' synthesis of MMP and TIMP proteins at different cell densities. It is shown that the cell lines with a low S100A4 level produced a reduced amount of immunoreactive MMP-2 at cellular subconfluence, while at confluence there was no difference compared to the control cells. The cell lines with a reduced S100A4 level produced less of the activated form of MMP-2 (62-kDa) and less TIMP-1 than the corresponding control cells, independent of cell density. Isolated cell membranes from cell lines with a reduced S100A4 level contained less MT1-MMP, MMP-2 and TIMP-2 compared to the control cells. Activation of exogenously added proMMP-2 was less effective with the former membrane preparations. It appeared that the mechanism behind the S100A4 dependent activation of proMMP-2 varied with cell density, as SN50, a peptide inhibitor of NF-kappaB nuclear translocation reduced the activation of MMP-2 at low cell density, but had no effect at high cell density. Thus, one of the mechanisms by which S100A4 may exert its effect on metastasis of some tumors is by regulating the MMP-2 activity.

The metalloproteinase inhibitor TIMP-2 is down-regulated by androgens in LNCaP prostate carcinoma cells

Tissue inhibitors of metalloproteinases (TIMPs) have been shown to perform several biological functions in tumor promotion, principally by their action of inhibiting matrix metalloproteinases (MMPs) at different steps of the metastatic process. In particular, TIMP-2 is involved in a functional complex with the membrane-type 1 (MT1) MMP to convert the secreted MMP-2 progelatinase into the fully active proteolytic enzyme. We used the human, androgen-sensitive prostate carcinoma cell line LNCaP in coculture with the human osteosarcoma cell line OHS to experimentally address the possibility of androgen-dependent regulatory effects on the functional MT1-MMP/TIMP-2/MMP-2 complex upon interaction between prostate carcinoma and osteoblastic cells in metastasis of prostate cancer to bone. In the LNCaP cells a gradual, time-dependent decline in TIMP-2 mRNA expression was observed in the presence of the synthetic androgen analogue R1881 (100 nM), reaching approximately 25% of the control level after 48 h of incubation. Consistent with this, the accumulation of secreted TIMP-2 in media from R1881-treated cells was significantly inhibited already after 3 h. Neither MMP-2 gelatinolytic activity nor expression of MT1-MMP was detected in LNCaP cells. In contrast, the OHS cells showed membrane-associated MT1-MMP expression as well as MMP-2 secretion. However, R1881 treatment of the LNCaP/OHS coculture model did not seem to change the overall proteolytic activity of the MT1 -MMP/TIMP-2/MMP-2 complex. Hormonal control of TIMP-2 expression in prostate carcinoma cells has not been previously reported, but whether such regulation has any functional role in the development of osteoblastic metastases in prostate cancer is still unclear.

Down-regulation of tissue inhibitor of matrix metalloprotease-1 (TIMP-1) in aged human skin contributes to matrix degradation and impaired cell growth and survival

Up regulation of matrix metalloproteinases (MMPs), particularly collagenase-1 (MMP-1), stromelysin-1 (MMP-3) and gelatinase A (MMP-2) is responsible for the lysis of dermal collagen and elastin fibers during chronological skin aging. Tissue inhibitor of metalloproteinase-1 (TIMP-1) is one representative of the natural MMP inhibitor family, encompassing four members. Its expression is decreased with fibroblast senescence, both ex vivo and in vivo, thus contributing to increased catabolic activity within dermis. TIMP-1 displays multiple biological functions. It inhibits most MMPs, except membrane-type MMP subfamily, with Ki in the subnanomolar range, but also interacts with the hemopexin-like (PEX) domain of pro MMP-9. Besides, it exhibits keratinocyte and fibroblast growth factor-like activity and has been described as a cell survival factor.

The favorable prognostic impact of tissue inhibitor of matrix metalloproteinases-1 protein overexpression in breast cancer cells

The tissue inhibitor of metalloproteinases-1 (TIMP1) inhibits tumor cell invasion and metastasis in experimental models; in addition, TIMP1 is supposed to possess another important function, cell growth promotion. The potential prognostic significance of TIMP1 in breast cancer remains unclear. We evaluated the significance of the immunohistochemical expression of TIMP1 in a well-documented series of 133 infiltrating breast carcinomas by examining any possible statistical association between this expression and numerous clinicopathological parameters as well as patients' disease-free interval. TIMP1 was generally expressed in both stromal and cancer cells in our specimens. TIMP1 was overexpressed in cancer cells of 60.15% of all cases. Tumors of high histological and nuclear grade were found to overexpress TIMP1 less frequently than the rest (p=0.003 and p=0.057, respectively). Interestingly, TIMP1 overexpression was inversely associated with cell proliferation, the latter being evidenced by Ki67 immunoreactivity (p=0.028). TIMP1 immunostaining was in parallel with metalloproteinase-2 (MMP2) immunoexpression in both cancer and stromal cells. Multivariate analysis disclosed that TIMP1 overexpression in cancer cells was an independent determining factor for prognosis (p=0.006); TIMP1 overexpression in malignant cells appeared to correlate with favorable outcome, particularly in patients with lack of nodal metastases and in patients with MMP2-negative immunophenotype (p=0.0252). The upregulation of TIMP1 cancer cell expression in breast cancer may suggest that this marker has a multifunctional role apart from that of metalloproteinase inhibitor since it was found to be related to malignant cells' differentiation and proliferation. TIMP1 overexpression in cancer cells appears for the first time to be a promising indicator of favorable prognosis in breast cancer.