Degradation of basement membranes by human matrix metalloproteinase 3 (stromelysin)

Instrumental and transcriptome analysis reveals the chemotherapeutic effects of doxorubicin-loaded black phosphate nanosheets on abiraterone-resistant prostate cancer

Prostate cancer is the second most common cause of cancer-related deaths in men and is common in most developed countries. Androgen deprivation therapy (ADT) that uses abiraterone acetate (AA) is an effective second-line treatment for prostate cancer. However, approximately 20-40% of patients develop primary resistance to abiraterone post-treatment. In this study, we aimed to understand the molecular mechanisms underlying the development of abiraterone resistance in prostate cancer cells and the potential use of black phosphorus nanosheets (BPNS) for treating abiraterone-resistant prostate cancer. We first established abiraterone-resistant prostate cancer PC-3 cells and found that these cells have higher migration ability than normal prostate cancer cells. Using comparative transcriptomic and bioinformatics analyses between abiraterone-sensitive PC-3 and abiraterone-resistant PC-3 cells, we highlighted the differentially expressed genes (DEGs) involved in the biological processes related to prostate gland morphogenesis, drug response, immune response, angiogenesis. We further studied the therapeutic effects of BPNS. Our results show that BPNS reduced the proliferation and migration of abiraterone-resistant PC-3 cells. Bioinformatics analysis, including gene ontology, Kyoto encyclopedia of genes and genomes enrichment analysis, and ingenuity pathway analysis (IPA) of the DEGs, suggested that BPNS treatment controlled cancer cell proliferation, metastasis, and oncogenic signaling pathways. Furthermore, the IPA gene network highlighted the involvement of the MMP family, ATF, and notch families in the anti-prostate cancer function of BPNS. Our findings suggest that BPNS may have a chemotherapeutic function in treating abiraterone-resistant prostate cancer.

Polymorphisms in genes related to oxidative stress and inflammation: Emerging links with the pathogenesis and severity of Cerebral Cavernous Malformation disease

Cerebral Cavernous Malformation (CCM) is a cerebrovascular disease of genetic origin affecting 0.5% of the population and characterized by abnormally enlarged and leaky capillaries that predispose to seizures, neurological deficits, and intracerebral hemorrhage (ICH). CCM occurs sporadically or is inherited as dominant condition with incomplete penetrance and highly variable expressivity. Three disease genes have been identified: KRIT1 (CCM1), CCM2 and CCM3. Previous results demonstrated that loss-of-function mutations of CCM genes cause pleiotropic effects, including defective autophagy, altered reactive oxygen species (ROS) homeostasis, and enhanced sensitivity to oxidative stress and inflammatory events, suggesting a novel unifying pathogenetic mechanism, and raising the possibility that CCM disease onset and severity are influenced by the presence of susceptibility and modifier genes. Consistently, genome-wide association studies (GWAS) in large and homogeneous cohorts of patients sharing the familial form of CCM disease and identical mutations in CCM genes have led to the discovery of distinct genetic modifiers of major disease severity phenotypes, such as development of numerous and large CCM lesions, and susceptibility to ICH. This review deals with the identification of genetic modifiers with a significant impact on inter-individual variability in CCM disease onset and severity, including highly polymorphic genes involved in oxidative stress, inflammatory and immune responses, such as cytochrome P450 monooxygenases (CYP), matrix metalloproteinases (MMP), and Toll-like receptors (TLR), pointing to their emerging prognostic value, and opening up new perspectives for risk stratification and personalized medicine strategies.

Tonsil-derived mesenchymal stem cells enhance allogeneic bone marrow engraftment via collagen IV degradation

BACKGROUND

Co-transplantation of bone marrow cells (BMCs) and mesenchymal stem cells (MSCs) is used as a strategy to improve the outcomes of bone marrow transplantation. Tonsil-derived MSCs (TMSCs) are a promising source of MSCs for co-transplantation. Previous studies have shown that TMSCs or conditioned media from TMSCs (TMSC-CM) enhance BMC engraftment. However, the factors in TMSCs that promote better engraftment have not yet been identified.

METHODS

Mice were subjected to a myeloablative regimen of busulfan and cyclophosphamide, and the mRNA expression in the bone marrow was analyzed using an extracellular matrix (ECM) and adhesion molecule-targeted polymerase chain reaction (PCR) array. Nano-liquid chromatography with tandem mass spectrometry, real-time quantitative PCR, western blots, and enzyme-linked immunosorbent assays were used to compare the expression levels of metalloproteinase 3 (MMP3) in MSCs derived from various tissues, including the tonsils, bone marrow, adipose tissue, and umbilical cord. Recipient mice were conditioned with busulfan and cyclophosphamide, and BMCs, either as a sole population or with control or MMP3-knockdown TMSCs, were co-transplanted into these mice. The effects of TMSC-expressed MMP3 were investigated. Additionally, Enzchek collagenase and Transwell migration assays were used to confirm that the collagenase activity of TMSC-expressed MMP3 enhanced BMC migration.

RESULTS

Mice subjected to the myeloablative regimen exhibited increased mRNA expression of collagen type IV alpha 1/2 (Col4a1 and Col4a2). Among the various extracellular matrix-modulating proteins secreted by TMSCs, MMP3 was expressed at higher levels in TMSCs than in other MSCs. Mice co-transplanted with BMCs and control TMSCs exhibited a higher survival rate, weight recovery, and bone marrow cellularity compared with mice co-transplanted with BMCs and MMP3-knockdown TMSCs. Control TMSC-CM possessed higher collagenase activity against collagen IV than MMP3-knockdown TMSC-CM. TMSC-CM also accelerated BMC migration by degrading collagen IV in vitro.

CONCLUSIONS

Collectively, these results indicate that TMSCs enhance BMC engraftment by the secretion of MMP3 for the modulation of the bone marrow extracellular matrix.

Elucidating cancer-vascular paracrine signaling using a human organotypic breast cancer cell extravasation model

In cancer metastasis, extravasation refers to the process where tumor cells exit the bloodstream by crossing the endothelium and invade the surrounding tissue. Tumor cells engage in complex crosstalk with other active players such as the endothelium leading to changes in functional behavior that exert pro-extravasation effects. Most in vitro studies to date have only focused on the independent effects of molecular targets on the functional changes of cancer cell extravasation behavior. However, singular targets cannot combat complex interactions involved in tumor cell extravasation that affects multiple cell types and signaling pathways. In this study, we employ an organotypic microfluidic model of human vasculature to investigate the independent and combined role of multiple upregulated secreted factors resulting from cancer-vascular interactions during cancer cell extravasation. The device consists of a tubular endothelial vessel generated from induced pluripotent stem cell derived endothelial cells within a collagen-fibrinogen matrix with breast cancer cells injected through and cultured along the lumen of the vessel. Our system identified cancer-vascular crosstalk, involving invasive breast cancer cells, that results in increased levels of secreted IL-6, IL-8, and MMP-3. Our model also showed that upregulation of these secreted factors correlates with invasive/metastatic potential of breast cancer cells. We also used therapeutic inhibitors to assess the independent and combined role of multiple signaling factors on the overall changes in functional behavior of both the cancer cells and the endothelium that promote extravasation. Taken together, these results demonstrate the potential of our organotypic model in elucidating mechanisms through which cancer-vascular interactions can promote extravasation, and in conducting functional assessment of therapeutic drugs that prevent extravasation in cancer metastasis.

X-box binding protein 1-mediated COL4A1s secretion regulates communication between vascular smooth muscle and stem/progenitor cells

Vascular smooth muscle cells (VSMCs) contribute to the deposition of extracellular matrix proteins (ECMs), including Type IV collagen, in the vessel wall. ECMs coordinate communication among different cell types, but mechanisms underlying this communication remain unclear. Our previous studies have demonstrated that X-box binding protein 1 (XBP1) is activated and contributes to VSMC phenotypic transition in response to vascular injury. In this study, we investigated the participation of XBP1 in the communication between VSMCs and vascular progenitor cells (VPCs). Immunofluorescence and immunohistology staining revealed that Xbp1 gene was essential for type IV collagen alpha 1 (COL4A1) expression during mouse embryonic development and vessel wall ECM deposition and stem cell antigen 1-positive (Sca1⁺)-VPC recruitment in response to vascular injury. The Western blot analysis elucidated an Xbp1 gene dose-dependent effect on COL4A1 expression and that the spliced XBP1 protein (XBP1s) increased protease-mediated COL4A1 degradation as revealed by Zymography. RT-PCR analysis revealed that XBP1s in VSMCs not only upregulated COL4A1/2 transcription but also induced the occurrence of a novel transcript variant, soluble type IV collagen alpha 1 (COL4A1s), in which the front part of exon 4 is joined with the rear part of exon 42. Chromatin-immunoprecipitation, DNA/protein pulldown and in vitro transcription demonstrated that XBP1s binds to exon 4 and exon 42, directing the transcription from exon 4 to exon 42. This leads to transcription complex bypassing the internal sequences, producing a shortened COL4A1s protein that increased Sca1⁺-VPC migration. Taken together, these results suggest that activated VSMCs may recruit Sca1⁺-VPCs via XBP1s-mediated COL4A1s secretion, leading to vascular injury repair or neointima formation.

Increased phosphorylation of eIF2α in chronic myeloid leukemia cells stimulates secretion of matrix modifying enzymes

Recent studies underscore the role of the microenvironment in therapy resistance of chronic myeloid leukemia (CML) cells and leukemia progression. We previously showed that sustained mild activation of endoplasmic reticulum (ER) stress in CML cells supports their survival and resistance to chemotherapy. We now demonstrate, using dominant negative non-phosphorylable mutant of eukaryotic initiation factor 2 α subunit (eIF2α), that phosphorylation of eIF2α (eIF2α-P), which is a hallmark of ER stress in CML cells, substantially enhances their invasive potential and modifies their ability to secrete extracellular components, including the matrix-modifying enzymes cathepsins and matrix metalloproteinases. These changes are dependent on the induction of activating transcription factor-4 (ATF4) and facilitate extracellular matrix degradation by CML cells. Conditioned media from CML cells with constitutive activation of the eIF2α-P/ATF4 pathway induces invasiveness of bone marrow stromal fibroblasts, suggesting that eIF2α-P may be important for extracellular matrix remodeling and thus leukemia cells-stroma interactions. Our data show that activation of stress response in CML cells may contribute to the disruption of bone marrow niche components by cancer cells and in this way support CML progression.

Membranous type matrix metalloproteinase 16 induces human prostate cancer metastasis

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes, which perform a crucial role in the metastatic spread of cancer. MMP2 and MMP9 are important cancer-associated MMPs in the invasion and metastasis of the majority of carcinomas. As a new member of the membrane-type MMPs, the function of MMP16 associated with invasion and metastasis of cancer remains unclear. In the present study, MMP16 expression in prostate cancer (PCa) tissues and cells was examined, and the high expression of MMP16 was revealed to be associated with advanced prostate tumor stage and PCa cell metastasis. The membrane localization of MMP16 is required for its function. To the best of our knowledge, the present study is the first to demonstrate that MMP16 is associated with advanced prostate tumor stage. As an important mediator of PCa cell metastasis, the membrane localization of MMP16 is required, and MMP16 may be an ideal target candidate for preventing PCa cell metastasis.

Tumor Necrosis Factor-α and IL-17A Activation Induces Pericyte-Mediated Basement Membrane Remodeling in Human Neutrophilic Dermatoses

Sweet syndrome (SS) is a prototypical neutrophilic dermatosis, a class of inflammatory diseases marked by elevated levels of tumor necrosis factor (TNF)-α and IL-17A, pathologic neutrophil recruitment, and microvascular remodeling. Histologic analyses of four matrix proteins-collagen I and IV, laminin, and fibronectin-in skin biopsies of patients with SS reveal that the basement membrane of dermal postcapillary venules undergoes changes in structure and composition. Increased neutrophil recruitment in vivo was associated with increases in collagen IV, decreases in laminin, and varied changes in fibronectin. In vitro studies using TNF-α and IL-17A were conducted to dissect basement membrane remodeling. Prolonged dual activation of cultured human pericytes with TNF-α and IL-17A augmented collagen IV production, similar to in vivo remodeling. Co-activation of pericytes with TNF-α and IL-17A also elevated fibronectin levels with little direct effect on laminin. However, the expression of fibronectin- and laminin-specific matrix metalloproteinases (MMPs), particularly MMP-3, was significantly up-regulated. Interactions between pericytes and neutrophils in culture yielded even higher levels of active MMPs, facilitating fibronectin and laminin degradation, and likely contributing to the varied levels of detectable fibronectin and the decreases in laminin observed in vivo. These data indicate that pericyte-neutrophil interactions play a role in mediating microvascular changes in SS and suggest that targeting MMP-3 may be effective in protecting vascular wall integrity.

Matrix Metalloproteinase Expression in the Rat Myometrium During Pregnancy, Term Labor, and Postpartum

Pregnancy, spontaneous term labor (TL), and postpartum (PP) involution are associated with changes in the cellular and extracellular matrix composition of the uterus. Both the uterine smooth muscle (myometrium) and the infiltrating peripheral blood leukocytes involved in the activation of labor secrete extracellular matrix-degrading enzymes (matrix metalloproteinases, MMPs) that can modulate cellular behavior and barrier function. MMP expression is induced by mechanical stretch in several tissues. We hypothesized that the expression and activity of myometrial MMPs and their tissue inhibitors (TIMPs) are modulated in preparation for TL and PP involution and are regulated by mechanical stretch of uterine walls imposed by the growing fetus. Myometrial tissues were collected from bilaterally and unilaterally pregnant rats across gestation, TL, and PP. Total RNA and proteins were subjected to real-time PCR and immunoblotting, respectively, and tissue localization and activity was examined by immunohistochemistry and in situ zymography. We found that Mmp7, Mmp11, and Mmp12 mRNA levels were upregulated during TL and PP, while Mmp2, Mmp3, Mmp8, Mmp9, Mmp10, and Mmp13 mRNAs were only upregulated during PP. Timp1–Timp4 were stably expressed throughout gestation with some fluctuations PP. Active MMP2 was induced in the empty uterine horn during gestation and in the gravid PP uterus, suggesting negative regulation by biological mechanical stretch. We conclude that specific subsets of uterine MMPs are differentially regulated in the rat myometrium in preparation for two major events: TL and PP uterine involution.

Role of Matrix Metalloproteinases in the Pathogenesis of Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. Studies revealed that the pathogenesis of TBI involves upregulation of MMPs. MMPs form a large family of closely related zinc-dependent endopeptidases, which are primarily responsible for the dynamic remodulation of the extracellular matrix (ECM). Thus, they are involved in several normal physiological processes like growth, development, and wound healing. During pathophysiological conditions, MMPs proteolytically degrade various components of ECM and tight junction (TJ) proteins of BBB and cause BBB disruption. Impairment of BBB causes leakiness of the blood from circulation to brain parenchyma that leads to microhemorrhage and edema. Further, MMPs dysregulate various normal physiological processes like angiogenesis and neurogenesis, and also they participate in the inflammatory and apoptotic cascades by inducing or regulating the specific mediators and their receptors. In this review, we explore the roles of MMPs in various physiological/pathophysiological processes associated with neurological complications, with special emphasis on TBI.

Assessment of the sensitivity and specificity of tissue-specific-based and anatomical-based optical biomarkers for rapid detection of human head and neck squamous cell carcinoma

OBJECTIVES

We propose the use of morphological optical biomarkers for rapid detection of human head and neck squamous cell carcinoma (HNSCC) by leveraging the underlying tissue characteristics in aerodigestive tracts.

MATERIALS AND METHODS

Diffuse reflectance spectra were obtained from malignant and contra-lateral normal tissues of 57 patients undergoing panendoscopy and biopsy. Oxygen saturation, total hemoglobin concentration, and the reduced scattering coefficient were extracted. Differences in malignant and normal tissues were examined based on two different groupings: anatomical site and morphological tissue type.

RESULTS AND CONCLUSIONS

Measurements were acquired from 252 sites, of which 51 were pathologically classified as SCC. Optical biomarkers exhibited statistical differences between malignant and normal samples. Contrast was enhanced when parsing tissues by morphological classification rather than anatomical subtype for unpaired comparisons. Corresponding linear discriminant models using multiple optical biomarkers showed improved predictive ability when accounting for morphological classification, particularly in node-positive lesions. The false-positive rate was retrospectively found to decrease by 34.2% in morphologically- vs. anatomically-derived predictive models. In glottic tissue, the surgeon exhibited a false-positive rate of 45.7% while the device showed a lower false-positive rate of 12.4%. Additionally, comparisons of optical parameters were made to further understand the physiology of tumor staging and potential causes of high surgeon false-positive rates. Optical spectroscopy is a user-friendly, non-invasive tool capable of providing quantitative information to discriminate malignant from normal head and neck tissues. Predictive models demonstrated promising results for real-time diagnostics. Furthermore, the strategy described appears to be well suited to reduce the clinical false-positive rate.

Human pathogens utilize host extracellular matrix proteins laminin and collagen for adhesion and invasion of the host

Laminin (Ln) and collagen are multifunctional glycoproteins that play an important role in cellular morphogenesis, cell signalling, tissue repair and cell migration. These proteins are ubiquitously present in tissues as a part of the basement membrane (BM), constitute a protective layer around blood capillaries and are included in the extracellular matrix (ECM). As a component of BMs, both Lns and collagen(s), thus function as major mechanical containment molecules that protect tissues from pathogens. Invasive pathogens breach the basal lamina and degrade ECM proteins of interstitial spaces and connective tissues using various ECM-degrading proteases or surface-bound plasminogen and matrix metalloproteinases recruited from the host. Most pathogens associated with the respiratory, gastrointestinal, or urogenital tracts, as well as with the central nervous system or the skin, have the capacity to bind and degrade Lns and collagen(s) in order to adhere to and invade host tissues. In this review, we focus on the adaptability of various pathogens to utilize these ECM proteins as enhancers for adhesion to host tissues or as a targets for degradation in order to breach the cellular barriers. The major pathogens discussed are Streptococcus, Staphylococcus, Pseudomonas, Salmonella, Yersinia, Treponema, Mycobacterium, Clostridium, Listeria, Porphyromonas and Haemophilus; Candida, Aspergillus, Pneumocystis, Cryptococcus and Coccidioides; Acanthamoeba, Trypanosoma and Trichomonas; retrovirus and papilloma virus.

The timeline of metalloprotease events during oligofructose induced equine laminitis development

REASON FOR PERFORMING STUDY

The role of matrix metalloproteases (MMPs) and the timeline of proteolysis during laminitis development are incompletely understood.

OBJECTIVES

To determine the temporal progression of selected MMPs and protease regulators during laminitis development.

METHODS

Five clinically normal Standardbred horses received, via nasogastric intubation, an oligofructose (OF) bolus (10 g/kg bwt). Laminitis induction proceeded for 48 h followed by euthanasia. Lamellar biopsies were obtained prior to dosing and at intervals during the treatment period for analysis (12, 18, 24, 30 and 36 h and at 48 h following euthanasia). Tissue samples were analysed by real-time PCR, zymography and western blotting.

RESULTS

Activation of proMMP-2 occurs either simultaneously or at least 12 h following lamellar basement membrane (BM) damage, while no activation of proMMP-9 is seen during OF laminitis induction. Aggrecanase gene expression increased initially at 12-18 h post OF dosing, similar to BM changes. Gene expression of TIMP-2, a MMP regulator, decreases during laminitis development.

CONCLUSIONS

The MMP-2/MT1-MMP complex may not play a major role in initiating lamellar BM damage. Aggrecanase and TIMP-2 gene expression appear related to BM lamellar changes.

POTENTIAL RELEVANCE

MMPs, historically thought to cause laminitis, do not appear to play an initiating role in the lamellar lesion. Other host derived proteases and degradation of alternative lamellar matrix components need to be considered.

Microglial activation and matrix protease generation during focal cerebral ischemia

Local environmental conditions contribute to the activation state of cells. Extracellular matrix glycoproteins participate in cell-cell boundaries within the microvascular and extravascular tissues of the central nervous system and provide a scaffold for the local environment. These conditions are altered during focal cerebral ischemia (and other central nervous system disorders) when extracellular matrix boundaries are degraded or when matrix proteins in the vascular circulation enter the neuropil as the microvascular permeability barrier is degraded. Microglia in the resting state become activated after the onset of ischemia. During activation these cells can express a number of factors and proteases, including latent matrix metalloproteinase-9 (pro-MMP-9). Whereas MMP-9 and MMP-2 are generated early during focal ischemia in select models, their cellular sources in vivo are still under study. In vitro microglia cells activate and respond to exposure to specific matrix proteins (eg, vitronectin, fibronectin) that circulate. Certain MMP inhibitors, specifically tetracycline derivatives, can modulate microglial activation and reduce injury volume in limited studies. But, the injury reduction relies on preinjury exposure to the tetracycline. Other studies underway suggest the hypothesis that microglial cell activation and pro-MMP-9 generation during focal cerebral ischemia is promoted in part by matrix proteins in the circulation that extravasate into the neuropil when the blood-brain barrier is compromised. These matrix proteins are known to activate microglia through their specific cell surface matrix receptors.

Matrix metalloproteinase-3 expression profile differentiates adaptive and maladaptive synaptic plasticity induced by traumatic brain injury

The interaction between extracellular matrix (ECM) and regulatory matrix metalloproteinases (MMPs) is important in establishing and maintaining synaptic connectivity. By using fluid percussion traumatic brain injury (TBI) and combined TBI and bilateral entorhinal cortical lesion (TBI + BEC), we previously demonstrated that hippocampal stromelysin-1 (MMP-3) expression and activity increased during synaptic plasticity. We now report a temporal analysis of MMP-3 protein and mRNA response to TBI during both degenerative (2 day) and regenerative (7, 15 day) phases of reactive synaptogenesis. MMP-3 expression during successful synaptic reorganization (following unilateral entorhinal cortical lesion; UEC) was compared with MMP-3 expression when normal synaptogenesis fails (after combined TBI + BEC insult). Increased expression of MMP-3 protein and message was observed in both models at 2 days postinjury, and immuohistochemical (IHC) colocalization suggested that reactive astrocytes contribute to that increase. By 7 days postinjury, model differences in MMP-3 were observed. UEC MMP-3 mRNA was equivalent to control, and MMP-3 protein was reduced within the deafferented region. In contrast, enzyme mRNA remained elevated in the maladaptive TBI + BEC model, accompanied by persistent cellular labeling of MMP-3 protein. At 15 days survival, MMP-3 mRNA was normalized in each model, but enzyme protein remained higher than paired controls. When TBI + BEC recovery was enhanced by the N-methyl-D-aspartate antagonist MK-801, 7-day MMP-3 mRNA was significantly reduced. Similarly, MMP inhibition with FN-439 reduced the persistent spatial learning deficits associated with TBI + BEC insult. These results suggest that MMP-3 might differentially affect the sequential phases of reactive synaptogenesis and exhibit an altered pattern when recovery is perturbed.

Molecular balance of capillary tube formation versus regression in wound repair: role of matrix metalloproteinases and their inhibitors

In this review, we discuss the identification of distinct matrix metalloproteinases (MMPs) and their inhibitors that differentially control the processes of capillary tube formation (morphogenesis) versus capillary tube regression in three-dimensional (3D) collagen matrices. This work directly relates to both granulation tissue formation and regression during wound repair. The membrane metalloproteinase, MT1-MMP (MMP-14), is required for endothelial cell (EC) tube formation using in vitro assays that mimic vasculogenesis or angiogenic sprouting in 3D collagen matrices. These events are markedly blocked by small interfering RNA (siRNA) suppression of MT1-MMP in ECs or by addition of tissue inhibitor of metalloproteinases (TIMPs)-2,-3, and -4 but not TIMP-1. In contrast, MMP-1 and MMP-10 are strongly induced during EC tube formation to regulate the process of tube regression (following activation by serine proteases) rather than formation. TIMP-1, which selectively inhibits soluble MMPs, blocks tube regression by inhibiting MMP-1 and MMP-10 while having no influence on EC tube formation. siRNA suppression of MMP-1 and MMP-10 markedly blocks tube regression without affecting tube formation. Furthermore, we discuss that pericyte-induced stabilization of EC tube networks in our model system appears to occur through EC-derived TIMP-2 and pericyte-derived TIMP-3 to block both the capillary tube formation and regression pathways.

Protective effect of matrix metalloproteinase inhibitors against epidermal basement membrane damage: skin equivalents partially mimic photoageing process

BACKGROUND

The epidermal basement membrane (BM) plays important roles in adhesion between epidermis and dermis, and in controlling epidermal differentiation. The BM has been reported to be damaged in sun-exposed skin. Although matrix metalloproteinases (MMPs) are believed to be involved in the BM damage, there is no good in vitro model for examining BM damage by MMPs or for exploring methods to protect the BM.

OBJECTIVES

To examine the involvement of MMPs in BM damage and approaches to protect the BM from such damage by using an in vitro skin-equivalent (SE) model.

METHOD

SE was prepared by culturing human keratinocytes on contracted collagen gel including human fibroblasts. MMP-1, -2, -3 and -9, laminin 5 and type IV and VII collagens were determined by specific sandwich ELISAs, and MMP-2 and MMP-9 were analysed by gelatin zymography. Histological examination of SE was also carried out.

RESULTS

Despite production of BM components such as laminin 5 and type IV and VII collagens in SEs, BM was rarely observed at the dermal-epidermal junction. Several MMPs, such as MMP-1, -2, -3 and -9, were observed to be present in conditioned media and some of them were in active forms. Tissue inhibitor of metalloproteinase (TIMP)-2 was not detected, although TIMP-1 was present. Synthetic MMP inhibitors, CGS27023A and MMP-inhibitor I, which inhibit MMP-1, -2, -3 and -9, markedly augmented deposition of laminin 5 and type IV and VII collagens at the dermal-epidermal junction, resulting in the formation of continuous epidermal BM.

CONCLUSIONS

Our results indicate that MMPs are involved in the degradation of BM in SEs, and that MMP inhibitors exert a protective effect against BM damage.

Expression of ets-1 transcription factor in human head and neck squamous cell carcinoma and effect of histamine on metastatic potential of invasive tumor through the regulation of expression of ets-1 and matrix metalloproteinase-3

BACKGROUND

Ets-1 controls the expression of critical genes involved in matrix remodeling. The matrix metalloproteinase-3 (MMP-3) and urokinase type plasminogen activator (uPA) are typical ets-1 responsive genes. Recent studies have shown an increase in histamine synthesis and content in various human neoplasias. We hypothesized that the increased local histamine overproduction contributed to activation of matrix remodeling through the activation of MMP-3 expression of peritumoral fibroblasts by means of ets-1 regulation in head and neck squamous cell carcinomas (HNSCCs).

METHODS

Paraffin-embedded sections of 30 HNSCCs were immunostained for ets-1. The presence of ets-1 and MMP-3 mRNA in tumor samples was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR). To simulate stromal reaction in vitro, cultured human mucosal fibroblast was used. The level of ets-1 and MMP-3 mRNA was compared by use of RT-PCR, as was their protein with flow-cytometry, in the presence or absence of basic fibroblast growth factor (bFGF) (10 ng/mL) and histamine (1 microM).

RESULTS

Correlation between ets-1 expression and clinicopathologic background was not significant. In all cases, expression of ets-1 was seen in the stroma. In in vitro study, histamine upregulates production of ets-1 and MMP-3 in cultured fibroblast, and bFGF can stimulate histamine expression in fibroblast. Immunofluorescence staining supported the results of RT-PCR and flow cytometry.

CONCLUSIONS

Ets-1 expression in HNSCCs has no prognostic value; however, ets-1 plays an important role in tumor-host interaction. Histamine may accelerate the spread of HNSCC through an ets-1-related mechanism.

MMP-1 activation by serine proteases and MMP-10 induces human capillary tubular network collapse and regression in 3D collagen matrices

Previous work has shown that endothelial cell (EC)-derived matrix metalloproteinases (MMPs) regulate regression of capillary tubes in vitro in a plasmin- and MMP-1 dependent manner. Here we report that a number of serine proteases can activate MMP-1 and cause capillary tube regression; namely plasma kallikrein, trypsin, neutrophil elastase, cathepsin G, tryptase and chymase. Plasma prekallikrein failed to induce regression without coactivators such as high molecular weight kininogen (HMWK) or coagulation Factor XII. The addition of trypsin, the neutrophil serine proteases (neutrophil elastase and cathepsin G) and the mast cell serine proteases (tryptase and chymase) each caused MMP-1 activation and collagen type I proteolysis, capillary tubular network collapse, regression and EC apoptosis. Capillary tube collapse is accompanied by collagen gel contraction, which is strongly related to the wound contraction that occurs during regression of granulation tissue in vivo. We also report that proMMP-10 protein expression is markedly induced in ECs undergoing capillary tube morphogenesis. Addition of each of the serine proteases described above led to activation of proMMP-10, which also correlated with MMP-1 activation and capillary tube regression. Treatment of ECs with MMP-1 or MMP-10 siRNA markedly delayed capillary tube regression, whereas gelatinase A (MMP-2), gelatinase B (MMP-9) and stromelysin-1 (MMP-3) siRNA-treated cells behaved in a similar manner to controls and regressed normally. Increased expression of MMP-1 or MMP-10 in ECs using recombinant adenoviral delivery markedly accelerated serine protease-induced capillary tube regression. ECs expressing increased levels of MMP-10 activated MMP-1 to a greater degree than control ECs. Thus, MMP-10-induced activation of MMP-1 correlated with tube regression and gel contraction. In summary, our work demonstrates that MMP-1 zymogen activation is mediated by multiple serine proteases and MMP-10, and that these events are central to EC-mediated collagen degradation and capillary tube regression in 3D collagen matrices.

Elevation of hippocampal MMP-3 expression and activity during trauma-induced synaptogenesis

The matrix metalloproteinase (MMP) enzyme family contributes to the regulation of a variety of brain extracellular matrix molecules. In order to assess their role in synaptic plasticity following traumatic brain injury (TBI), we compared expression of stromelysin-1 (MMP-3) protein and mRNA in two rodent models of TBI exhibiting different levels of recovery: adaptive synaptic plasticity following central fluid percussion injury and maladaptive synaptic plasticity generated by combined TBI and bilateral entorhinal cortical lesion (TBI + BEC). We sampled the hippocampus at 7 days postinjury, targeting a selectively vulnerable brain region and a survival interval exhibiting rapid synaptogenesis. We report elevated expression of hippocampal MMP-3 mRNA and protein after TBI. MMP-3 immunohistochemical staining showed increased protein levels relative to sham-injured controls, primarily localized to cell bodies within the deafferented dendritic laminae. Injury-related differences in MMP-3 protein were also observed. TBI alone elevated MMP-3 immunobinding over the stratum lacunosum moleculare (SLM), inner molecular layer and hilus, while TBI + BEC generated more robust increases in MMP-3 reactivity within the deafferented SLM and dentate molecular layer (DML). Double labeling with GFAP confirmed the presence of MMP-3 within reactive astrocytes induced by each injury model. Semi-quantitative RT-PCR revealed that MMP-3 mRNA also increased after each injury, however, the combined insult induced a much greater elevation than fluid percussion alone: 1.9-fold vs. 79%, respectively. In the TBI + BEC model, MMP-3 up-regulation was spatio-temporally correlated with increased enzyme activity, an effect which was attenuated with the neuroprotective compound MK-801. These results show that distinct pathological conditions elicited by TBI can differentially affect MMP-3 expression during reactive synaptic plasticity. Notably, these effects are both transcriptional and translational and are correlated with functionally active enzyme.

Inhibition of human MDA-MB-231 breast cancer cell invasion by matrix metalloproteinase 3 involves degradation of plasminogen

Matrix metalloproteinase (MMP)-3 inhibited human MDA-MB-231 breast cancer cell invasion through reconstituted basement membrane in vitro. Inhibition of invasion was dependent upon plasminogen and MMP-3 activation, was impaired by the peptide MMP-3 inhibitor Ac-Arg-Cys-Gly-Val-Pro-Asp-NH2 and was associated with: rapid MMP-3-mediated plasminogen degradation to microplasminogen and angiostatin-like fragments; the removal of single-chain urokinase plasminogen activator from MDA-MB-231 cell membranes; impaired membrane plasminogen association; reduced rate of tissue plasminogen activator (t-PA) and membrane-mediated plasminogen activation; and reduced laminin-degrading capacity. Purified human plasminogen lysine binding site-1 (kringles 1-3) exhibited a similar capacity to inhibit MDA-MB-231 invasion, impair t-PA and cell membrane-mediated plasminogen activation and impair laminin degradation by plasmin. Our data provide evidence that MMP-3 can inhibit breast tumour cell invasion in vitro by a mechanism involving plasminogen degradation to fragments that limit plasminogen activation and the degradation of laminin. This supports the hypothesis that MMP-3, under certain conditions, may protect against tumour invasion, which would help to explain why MMP-3 expression, associated with benign and early stage breast tumours, is frequently lost in advanced stage, aggressive, breast disease.

Human macrophage metalloelastase worsens the prognosis of pancreatic cancer

OBJECTIVE

To evaluate the role of human macrophage metalloelastase (HME) in pancreatic cancer.

SUMMARY BACKGROUND DATA

HME, a member of the human matrix metalloproteinase family, possesses elastolytic activity and is critical for the degradation of extracellular matrix proteins. Inasmuch as tumor invasion and metastasis formation require lysis of extracellular matrix, HME plays a critical role in both processes.

METHODS

HME expression was analyzed by Northern blot analysis, reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunohistochemistry in 39 pancreatic cancer tissues and 13 normal controls. The molecular data were related to clinicopathologic parameters and patient survival.

RESULTS

In human pancreatic cancer, overexpression of HME mRNA was present in 25 of 39 pancreatic cancer tissues (64%) and in five pancreatic cancer cell lines. In contrast, low levels of HME mRNA expression were present in 13 normal pancreatic tissues samples. By Western blot analysis, high levels of HME were found in pancreatic cancer tissues and in the pancreatic cancer cell lines compared with the normal controls. Fifty-six percent of the cancer samples exhibited HME immunoreactivity in the cancer cells, and 63% in the stromal cells. Analysis of the survival data revealed that patients whose tumors exhibited HME mRNA overexpression lived significantly shorter compared with patients whose tumors did not overexpress HME. No relationship between HME expression and tumor stage, tumor grading, or presence of lymph node metastases was found.

CONCLUSIONS

These findings indicate that HME participates in pancreatic cancer progression and that its presence worsens the prognosis. These data suggest a benefit of its inhibition in the treatment of pancreatic cancer.

Importance of balance between extracellular matrix synthesis and degradation in basement membrane formation

The epidermal basement membrane (BM) plays important roles in adhesion between epidermis and dermis and in controlling epidermal differentiation. In a skin-equivalent (SE), components of the epidermal BM such as laminin 5 and type IV and VII collagens were detected in conditioned media and in basal keratinocytes. Despite production of these BM components, however, BM was rarely observed at the dermal-epidermal junction. One possible explanation for the absence of BM in SEs is that matrix metalloproteinases (MMPs) degrade newly synthesized extracellular matrices. In fact, several MMPs, such as MMPs-1, 2, 3, and 9, were observed to be present in conditioned media and some of them were in active forms. Tissue inhibitor of metalloproteinase (TIMP)-2 was not detected, although TIMP-1 was present. BM degradation activity presumably exceeds BM formation activity in the SE, resulting in the absence of lamina densa at the dermal-epidermal junction. Synthetic MMP inhibitors CGS27023A and MMP inhibitor I, which inhibit MMPs 1, 2, 3, and 9, markedly augmented deposition of laminin 5 and type IV and VII collagens at the dermal-epidermal junction, resulting in formation of continuous epidermal BM. These results suggest that the balance between synthesis and degradation of BM components is important for BM formation.

Different adhesins for type IV collagen on Candida albicans: identification of a lectin-like adhesin recognizing the 7S(IV) domain

Adherence of the opportunistic pathogen Candida albicans to basement membrane (BM) proteins is considered a crucial step in the development of candidiasis. In this study the interactions of C. albicans yeast cells with the three main domains of type IV collagen, a major BM glycoprotein, were analysed. C. albicans adhered to the three immobilized domains by different mechanisms. Adhesion to the N-terminal cross-linking domain (7S) required the presence of divalent cations, whereas interaction with the central collagenous domain (CC) was cation-independent. Recognition of the C-terminal non-collagenous domain (NC1) was partially cation-dependent. Binding inhibition assays with the corresponding domains in soluble form showed that these interactions were specific. Both Ca(2+) and Mg(2+) promoted adhesion to the 7S domain and the interaction was completely abolished by EDTA. Treatment of the 7S domain, or its subunits, with N-glycosidase F reduced yeast binding by approximately 70%. Moreover, several sugars known to be part of the N-linked oligosaccharide chains of collagen IV inhibited adhesion to immobilized 7S; N-acetylglucosamine, L-fucose and methylmannoside caused a similar inhibition whereas N-acetyllactosamine was a more effective inhibitor. In contrast, glucose, galactose, lactose or heparan sulfate did not affect yeast binding. Combinations of the inhibitory sugars at suboptimal inhibition concentrations did not reduce C. albicans adhesion more than the individual sugars, pointing to a single lectin as responsible for the interaction. These results taken together show that C. albicans utilizes several adhesins for interacting with type IV collagen, and that at least one of them is a lectin which recognizes the 7S(IV) oligosaccharide residues as its receptor.

Regulation of matrix metalloproteinases and their inhibitor genes in lipopolysaccharide-induced endotoxemia in mice

An imbalance between matrix metalloproteinases (MMPs) and inhibitors of MMPs (TIMPs) may contribute to tissue destruction that is found in various inflammatory disorders. To determine in an in vivo experimental setting whether the inflammatory reaction in the course of lipopolysaccharide (LPS)-induced endotoxemia causes an altered balance in the MMP/TIMP system, we analyzed the expression of a number of MMP and TIMP genes as well as MMP enzymatic activity in the liver, kidney, spleen, and brain at various time points after systemic injection of different doses of LPS in mice. Injection of sublethal doses of LPS led to an organ- and time-specific pattern of up-regulation of several MMP genes and the TIMP-1 gene in the liver, spleen, and kidney, whereas in the brain only TIMP-1 was induced. Injection of a lethal dose of LPS caused similar but more prolonged expression of these MMP genes as well as the induction of additional MMP genes in all organs. In LPS-treated mice in situ hybridization revealed collagenase 3 gene induction in cells resembling macrophages whereas TIMP-1 RNA was detected predominantly in parenchymal cells. Finally, gelatin zymography revealed increased gelatinolytic activity in all organs after LPS treatment. These observations highlight a dramatic shift in favor of increased expression of the MMP genes over the TIMP genes during LPS-induced endotoxemia, and suggest that MMPs may contribute to the development of organ damage in endotoxemia.

Evidence of in situ stability of the type IV collagen triple helix in human inflammatory bowel disease using a denaturation specific epitope antibody

A peptide specific antibody (AH1OW1) was raised against an epitope, AH10 (aa 449-463), of the alpha1(IV) chain adjacent to a cleavage site for matrix metalloproteinases (MMP)-2 and -9 within the triple helix of type IV collagen. The antibody only reacted with denatured and reduced preparations of type IV collagen, or with pepsin isolated type IV collagen digested with MMP-2 and MMP-9. The specificity of this antibody for the denatured triple helix was demonstrated by the lack of staining with pre-immune antibody and by pre-incubation of AH1OW1 antibody with excess AH10 peptide epitope. The AH1OWI antibody was used to detect whether proteolysis of type IV collagen occurs in ulcerative colitis, an inflammatory bowel condition often characterised by a large influx of granulocytes and macrophages and an associated tissue destruction. However, no evidence of in situ proteolysis of the basement membrane type IV collagen was observed. Only in the most actively inflamed mucosa was staining with AH1OW1 antibody observed in the mucosal connective tissue. Digestion of frozen sections of bowel with MMP-1, MMP-2, MMP-3 and MMP-9 did not result in the exposure of the AH10 epitope. These data demonstrate the stability of intact type IV collagen and indicate that susceptibility of alpha1(IV) chain to digestion with MMP-2 and MMP-9 may require other proteolytic/denaturing events in the molecule.

Nonenzymatic glycation of type IV collagen and matrix metalloproteinase susceptibility

The glomerular basement membrane (GBM) is damaged in diabetes through complex mechanisms that are not fully understood. Prominent among them is nonenzymatic protein glycation leading to the formation of so-called advanced glycation end products (AGEs). We examined the effects of in vitro glycation of intact collagen type IV in bovine lens capsule (LBM) and kidney glomerular (GBM) basement membranes on their susceptibility to matrix metalloproteinases, using stromelysin 1 (MMP-3) and gelatinase B (MMP-9). Sites of cleavage of unmodified LBM collagen were located in the triple helical region. In vitro glycation by glucose severely inhibited the release of soluble collagen cleavage peptides by MMP-3 and MMP-9. The distribution of AGEs within the three domains of collagen IV (7S, triple helical, and noncollagenous NC1) were compared for LBM glycation using AGE fluorescence, pentosidine quantitation, and immunoreactivity towards anti-AGE antibodies that recognize the AGE carboxymethyllysine (CML). Marked asymmetry was observed, with the flexible triple helical domain having the most pentosidine and fluorescent AGEs but the least CML. The in vivo relevance of these findings is supported by preliminary studies of AGE distribution in renal basement membrane (RBM) collagen IV domains from human kidneys of two insulin-dependent diabetics and one normal subject. Pentosidine and fluorescent AGE distributions of diabetic RBM were similar to LBM, but the CML AGE in diabetic kidney was less in the triple helical domain than in NC1. Our results support the hypothesis that nonenzymatic glycation of collagen IV contributes to the thickening of basement membranes, a hallmark of diabetic nephropathy.

Regulation of MMP-9 (92 kDa type IV collagenase/gelatinase B) expression in stromal cells of human giant cell tumor of bone

Matrix metalloproteinases (MMPs) play an important regulatory role in tissue morphogenesis, cell differentiation, tumor invasion and metastasis. Several authors have reported a direct correlation between the production of 72 kDa (MMP-2) and 92 kDa (MMP-9) type IV collagenases/gelatinases and the metastatic potential of cancer cells. Recently, we have identified the expression of both MMP-2 and MMP-9 in primary cultures of human giant cell tumor (GCT) of bone in vitro, and in tissue extracts in vivo. Interestingly, MMP-9 is not secreted by late-passaged GCT cells. It is possible that the production of MMP-9 is regulated by certain factor(s) secreted by the multinucleated giant cells in the primary culture. In order to test this hypothesis, the effect of primary-culture-conditioned medium on the expression of MMP-9 by late-passaged mononuclear stromal cells was examined. Adding conditioned medium from the primary GCT culture to the late-passaged stromal cells induced MMP-9, as evidenced by the presence of lytic bands at M(r) 92,000 and 72,000 on a gelatin zymogram. These enzyme activities were inhibited by EDTA, a well-known inhibitor of the MMPs. We confirmed these results by Western blotting using specific antibodies and RT-PCR for MMP-2 and MMP-9. Immunofluorescence studies with specific antibodies to MMP-9 further confirmed its expression by the passaged stromal cells cultured in the primary-culture-conditioned medium. The data indicate that MMP-2 and MMP-9 are produced by the mononuclear stromal cells when cultured in GCT primary-culture-conditioned medium. This suggests that multinucleated giant cells in primary cultures secrete a factor(s) that stimulates stromal cells to produce MMP-9, which, in turn, may contribute to the aggressive behavior of GCT.

Matrix metalloproteinase (stromelysin-1) increases the albumin permeability of isolated rat glomeruli

Matrix metalloproteinases (MMPs) secreted by connective tissue cells are capable of acting on extracellular matrix components of glomerular basement membrane at a slow rate and thus may play a role in the control of protein permeability and in the progression of certain kinds of glomerulonephritis. We have used an in vitro assay to measure the direct effect of three MMPs and human neutrophil elastase on glomerular albumin permeability (Palbumin). Glomeruli were isolated from normal male Sprague-Dawley rats and suspended in isolation medium with or without interstitial collagenase, gelatinase-A, stromelysin-1, or elastase and were incubated at 37 degrees C for up to 4 hours. A tissue-specific inhibitor of matrix metalloproteinases (TIMP-1) and a plasma proteinase inhibitor, alpha2-macroglobulin (alpha2M), were used to block the activity of MMPs. Palbumin was calculated from the change in glomerular volume in response to an applied oncotic gradient. In this study stromelysin-1 (10 microg/ml) and elastase (5 microg/ml) increased Palbumin significantly. Stromelysin-1 increased Palbumin after 4 hours, whereas elastase had an effect after 2 hours. Lower concentrations of stromelysin-1 or shorter incubation time had no effect on Palbumin. Incubation for up to 4 hours with interstitial collagenase (10 microg/ml) or gelatinase-A (10 microg/ml) had no effect on Palbumin. Coincubation with TIMP-1 and alpha2M blocked the stromelysin-1-mediated increase in Palbumin. We conclude that stromelysin-1 is capable of affecting the glomerular filtration barrier directly and that it may play an important role in causing proteinuria in glomerular diseases.

Opposite, binary regulatory pathways involved in IL-1-mediated stromelysin gene expression in rat mesangial cells

Glomerular mesangial cells express matrix metalloproteinase sromelysin in response to the proinflammatory cytokine IL-1 beta. The present study was conducted to identify intracellular machinery involved in this IL-1 action, especially focusing on the role of the TPA response element (TRE) located in the 5'-flanking region of the stromelysin gene. Using transient transfection with a pTRE-LacZ reporter plasmid, we detected no obvious up-regulation of TRE activity in rat mesangial cells following the IL-1 stimulation. However, the basal activity of TRE was found to be essential to the stromelysin induction, since (i) mesangial cells stably expressing a transdominant negative mutant of c-Jun, which effectively suppressed both basal and inducible TRE activity, exhibited the blunted expression of stromelysin in response to IL-1 beta, whereas (ii) transfection with a c-fos antisense gene, which suppressed only the inducible TRE activity, did not affect the stromelysin induction. To seek cooperative pathways required for the IL-1 action, we next focused on protein kinases, the potential regulators of the stromelysin gene. Stimulation of mesangial cells with a protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), induced the stromelysin transcript without affecting TRE activity. Depletion of intracellular PKC by high-dose PMA or inhibition of PKC activity with calphostin C suppressed the stromelysin induction by IL-1 beta, suggesting the crucial contribution of a PKC-mediated, but TRE-independent pathway. In contrast, either cAMP inducer forskolin or dibutyryl cAMP suppressed the IL-1-mediated stromelysin expression. An inhibitor of cAMP-dependent protein kinase A (PKA), HA1004, enhanced the IL-1 effect in a dose-dependent manner. Unexpectedly, the inhibitory action of PKA was not through cAMP response element (CRE) but through TRE, because (i) activation of CRE was not induced by IL-1 beta, and (ii) cAMP-mediated activation of PKA suppressed the basal TRE activity. These findings elucidated the unique, binary regulation of stromelysin by IL-1 beta; that is, IL-1 up-regulated the transcript via the PKC-dependent pathway under the cooperation with constitutively active TRE, and this stimulatory effect was in part counterbalanced by the IL-1-inducible PKA which down-regulated the basal TRE activity.

Expression of matrix-metalloproteinases and their inhibitors in human cholesteatomas

The proteolytic erosion of the temporal bone is the key event in the pathognomonic course of cholesteatoma progression. The molecular mechanisms of bone resorption, endangering the ossicles, the inner ear, the facial nerve, large vessels or the brain, are not understood. Recently, a new family of proteolytic enzymes, the matrix-metalloproteinases (MMP's) has been described and identified, which seems to play a pivotal role in matrix- and bone homeostasis and inflammatory osteolytic diseases, e.g. osteoarthritis and periodontitis. These enzymes are sophisticatedly controlled by specific inhibitors and activation cascades. We investigated whether human cholesteatoma tissue expresses MMP's and MMP-inhibitors. By immunocytochemistry of cholesteatoma-cryosections, the expression of MMP-2 (72 kD collagenase), MMP-9 (92 kD collagenase), and MMP-3 (stromelysin-1) could be seen to be strictly confined to the basal and suprabasal cell layer of the cholesteatoma epithelium. The neutrophil collagenase (MMP-8) showed a more disseminated expression in the epithelium and the granulation tissue as well. The tissue inhibitor of metalloproteases, TIMP-1, could be detected only in very limited areas of the granulation tissue in a quite randomized manner. Therefore, a derailment in favor of proteolysis of the normally tightly controlled MMP-system might be postulated. The results indicate that members of the MMP-family could play an active role in the molecular mechanisms of cholesteatoma invasion into the temporal bone. This offers new insights into the pathophysiology of the disease and of potential therapeutic approaches.

Serum type IV collagen in various liver diseases in comparison with serum 7S collagen, laminin, and type III procollagen peptide

The clinical significance of the immunoreactive triple helical domain of type IV collagen in serum was evaluated in 73 healthy controls and 161 patients with various biopsy-proven liver diseases. Although serum levels of type III procollagen peptide were increased in all liver diseases, those of type IV collagen, 7S collagen, and laminin were principally increased in chronic liver diseases associated with hepatic fibrogenesis/fibrosis. In both non-alcoholic and alcoholic liver diseases, 7S collagen was increased in serum, while type IV collagen and laminin in serum were particularly increased in alcoholic liver diseases and in hepatocellular carcinoma, in which latter the sensitivity was greater for type IV collagen than for laminin. Gel filtration analysis in Sephacryl S-400 revealed type IV collagen in serum to be a single molecular form with a molecular weight that correspond to type IV collagen, whereas 7S collagen was recognized as several heterogeneous macromolecules. These findings indicate that serum type IV collagen is derived from the type IV protocollagen pool, and is a sensitive marker for the fibrogenetic process in hepatic basement membranes.

Invasion and metastasis

The invasive character of squamous cell carcinoma of the head and neck represents a major challenge to the clinician since most often these tumors require extensive surgical resection impairing important physiological functions including speech and swallowing. Additionally, in many cases costly reconstructive surgery is required to repair the adverse cosmetic effects of the resective surgery. Thus, there is an urgent need to understand the molecular mechanism(s) which underlie the local and regional spread of this disease. Since the ability of tumor cells to invade into surrounding structures requires hydrolytic action much effort has been spent on identifying the hydrolases involved in this process. Some of the enzymes which have been implicated in the spread of head and neck cancer include the urokinase-type plasminogen activator and several members of the collagenase family such as type I and IV collagenases and the stromelysins synthesized either by the tumor cells or in the surrounding fibroblasts. More recent studies have addressed the mechanism(s) by which these hydrolases are overexpressed in invasive cancer. In the tumor cells themselves, work has focused on defining the transcriptional requirements for enzyme synthesis and addressing how the appropriate transcription factors are activated by signal transduction pathways. In contrast, where the hydrolases (e.g. stromelysin-2 and stromelysin-3) are produced by the fibroblasts, current investigations are directed at identifying tumor-derived growth factors which lead to the inducible expression of the enzymes in the stromal cells. The ultimate goal of these studies is to develop novel therapeutic interventions which decrease the invasive capacity of head and neck cancer leading to longer survival times and enhanced quality of life for patients afflicted with this disease.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in human gliomas

The gene expression of five matrix metalloproteinases (MMPs) and two tissue inhibitors of metalloproteinases (TIMPs) was studied in human gliomas in vivo and in vitro to evaluate their roles in glioma invasion. Simultaneous expression of one to four MMP genes and two TIMP genes was found in 17 surgical glioma specimens, and one MMP (gelatinase A) gene and two TIMP genes were simultaneously expressed in tissue of three brains. The concomitant overexpression of gelatinase A, gelatinase B, and occasional matrilysin genes was associated with the malignancy of gliomas and accompanied by overexpression of the TIMP-1 gene. In five human glioma cell lines, gelatinase A, TIMP-1, and TIMP-2 genes were constitutively expressed in alll cell lines: the matrilysin gene in three cell lines; the stromelysin gene in two cell lines; and the interstitial collagenase gene in one cell line. There was a clear difference in the expression of gelatinase B and stromelysin genes between surgical glioma specimens and glioma cell lines: the gelatinase B gene was not expressed constitutively in vitro but was overexpressed in vivo, whereas the stromelysin gene was not expressed in vivo but was expressed in some cell lines. To find the cause of that difference in vivo and in vitro, the transcriptional regulations of MMP and TIMP genes by tumor promoter, growth factors, or cytokines were studied in vitro. Interstitial collagenase, gelatinase B, stromelysin, and TIMP-1 genes were upregulated in many cell lines by phorbol-12-myristate-13-acetate (PMA) and in some cell lines by epidermal growth factor, tumor necrosis factor-alpha, or interleukin-1 beta. Transforming growth factor-beta 1 (TGF beta 1) upregulated gelatinase A and matrilysin genes in some cell lines, and there were no clear responses from any MMP and TIMP genes to interleukin-6. Thus, the transcriptional modulation of MMP genes by these growth factors and cytokines seemed insufficient to explain the difference in gelatinase B and stromelysin gene expressions in vivo and in vitro and was suggestive of the genetic alteration of glioma cells in vitro, the heterogeneous cell population in glioma tissues, or both. Furthermore, the in vitro invasion of glioma cells through Matrigel in response to PMA, TGF beta 1, or TIMP-1 was assessed by chemoinvasion assay. In most cell lines, invasion was significantly stimulated by PMA or TGF beta 1 but suppressed by TIMP-1.(ABSTRACT TRUNCATED AT 400 WORDS)

Expression of stromelysin-1 and TIMP-1 in the involuting mammary gland and in early invasive tumors of the mouse

The mammary gland, during post-lactational involution, is subjected to extensive tissue reconstruction. This process is governed by the concerted expression of extracellular-matrix-degrading enzymes and their inhibitors. During carcinogenesis, the invasive growth of tumor cells is characterized by the penetration of the basement membrane and stromal invasion. We compared the expression of the tissue-remodeling enzymes stromelysin-1, a matrix metalloproteinase, and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), during mammary gland involution and carcinogenesis in mouse. In involuting mammary glands, stromelysin-1 was expressed in myoepithelial cells, whereas TIMP-1 was confined to the stromal tissue. To analyze the involvement of these tissue-remodeling genes in tumor development, we examined mammary tumors of transgenic mice expressing either the activated Ha-ras or c-myc oncogene under the control of a milk-protein gene promoter. In the undifferentiated and metastasizing Ha-ras-induced tumors, stromelysin-1 expression was comparable to that seen in involution, whereas TIMP-1 expression was greatly elevated. During Ha-ras-induced carcinogenesis, stromelysin-1 expression was first detected in the myo-epithelial cells surrounding preneoplastic lesions. In contrast, in the well-differentiated and non-metastatic mammary tumors induced by c-myc, no expression of either gene was observed. Thus, expression of stromelysin-1 and TIMP-1 is confined to the aggressively growing tumors and is induced in the earliest stages of carcinogenesis.

Gene transfer of metalloproteinase transin induces aberrant behavior of cultured mesangial cells

The aim of the present study is to clarify whether the cellular expression of a matrix-degrading metalloproteinase, transin, alters the behavior of cultured mesangial cells (MCs). The cDNA encoding rat transin was introduced into rat MCs and transcribed under the control of a Rous sarcoma virus promoter. The resulting transfectants were then investigated for cell shape, migration, proliferation, and expression of genes associated with matrix metabolism. Northern blot analysis routinely detected the transin transcript in two separate transfectants, MeTRN2 and MeTRN5. Transin expression was strong in MeTRN2, moderate in MeTRN5, but absent in mock transfectants. Immunoblot analysis revealed that these transin transfectants synthesized 59 and 62 kDa molecules, which correspond to transin gene products. Casein digestion assay detected enhanced proteolytic activity in MeTRN2 and MeTRN5. Microscopically, the transfected cells were somewhat elongated with accentuated margins compared with mock transfectants. [3H]-thymidine uptake studies revealed accelerated growth of the transfectants on a plastic substratum as well as within gel matrix. The migration of the transfectants into gel matrix was also significantly enhanced compared with that of mock transfectants. No obvious alteration, however, was found in transcripts of procollagen alpha 1(IV), laminin B2, or the metalloproteinase inhibitor TIMP. We hypothesize that the metalloproteinase transin has a potential for affecting the behavior of MCs and contributing to the pathogenesis of glomerular injury.

Brainstem and other malignant gliomas: II. Possible mechanisms of brain infiltration by tumor cells

Gliomas that arise in the brain stem and other malignant gliomas constitute approximately 60% of all brain tumors and have eluded effective therapy, in part because they are able to infiltrate the normal brain. Histopathologic studies have confirmed the presence of infiltrating tumor cells very distant from the glioma mass. We review the neuroimaging and pathologic features of glioma-cell infiltration and some of the complex cellular and biochemical determinants of tumor-cell motility and invasiveness. Understanding how glioma cells become motile and invasive is pivotal to therapeutically targeting the machinery that enables gliomas to infiltrate the brain.

The glycosaminoglycans in cultures of stimulated rat peritoneal macrophages. 2. Gel chromatographic studies and the behaviour of heparan sulfate

The molecular weight distribution of pMP-derived glycosaminoglycans (GAG), i.e. non-sulfated GAG, chondroitin sulfate (CS), and heparin sulfate (HS)-like material was determined. The peritoneal macrophages (pMP) were harvested from rats normal or stimulated by i.p. injection of thioglycolate, carrageenan or BCG, and maintained in culture. The GAG of cell layer and medium were isolated separately after labeling with 35S-sulfate and 3H-acetate. Treatment with nitrous acid served to remove HS-like material. Labeling with 3H-acetate served to detect synthesis of the high m. w. hyaluronic acid (HA). Gel chromatic separation was done using Sephadex G-200 columns. The maximal size of 35S-labeled GAG, especially HS (36 kDa), was reduced in cultural medium and cell layer after stimulation in vivo. Reduction was most pronounced after application of carrageenan followed by thioglycolate and BCG/LPS stimulation. The extracellular GAG of BCG-stimulated pMP were smallest, probably due to degradation. Heparan sulfate-like material made up a larger proportion in monolayer and medium, comprising the total m.w. range up to 36 kDa. The GAG sensitive to nitrous acid were maximal in cultures of carrageenan-stimulated pMP and minimal in those of thioglycolate-stimulated pMP. This type of HS was sensitive to hyaluronidase, too. Any synthesis of high molecular hyaluronic acid was not found in normal or stimulated rat pMP. Therefore MP-associated HA must be adsorbed from other sources or synthesized by early forms of macrophages.

Dissociation of collagenase-tissue inhibitor of metalloproteinases-1 (TIMP-1) complex--its application for the independent measurements of TIMP-1 and collagenase activity in crude culture media and body fluids

Collagenase-tissue inhibitor of metalloproteinases-1 (TIMP-1) complex was prepared from activated collagenase and TIMP-1 purified from culture media of human skin fibroblasts. After having been confirmed to be a complex by zinc chelate chromatography, the complex was demonstrated to dissociate by passage through an anti-TIMP-1 monoclonal antibody-affinity column. On the basis of above evidence, a simple strategy was set up for the independent measurements of TIMP-1 concentration, and both active and total collagenase activities in crude culture media and body fluids.

Production of matrix metalloproteinases 2 and 3 (stromelysin) by stromal cells of giant cell tumor of bone

Matrix metalloproteinases play a central role in the catabolism of extracellular matrix macromolecules. Here the authors report that giant cell tumor of bone (GCT) produces two matrix metalloproteinases (MMPs) in zymogen form, which have been identified as proMMP-2 (also known as "72-kDa-progelatinase/type IV procollagenase") and proMMP-3 (prostromelysin). Giant cell tumor is known to consist of two major cell populations, multinucleated giant cells and stromal cells. On several passages of the tumor cells in culture, only stromal cells proliferated. These stromal cells produced proMMP-2 but not proMMP-3. Addition of the conditioned medium of primary GCT culture or human macrophage-conditioned medium to the passaged stromal cells induced the production of proMMP-3. The production of proMMP-3 was also induced by interleukin 1 (IL-1), but not by tumor necrosis factor alpha (TNF alpha). ProMMP-1 (tissue procollagenase) was not detected even after treatment with these stimuli. Immunohistochemical studies have demonstrated that multinucleated giant cells in GCT both produce IL-1 and TNF alpha, suggesting that IL-1 secreted by multinucleated giant cells may be responsible for in vivo production of proMMP-3 by the stromal cells. The authors propose that GCT has a self-stimulatory system for the production of matrix-degrading proteinases and that the ability of the passaged stromal cells to synthesize and secrete proMMP-3 with appropriate stimuli may contribute the malignant behavior of GCT.

Expression of collagenase-related metalloproteinase genes in human lung or head and neck tumours

We address the question as to whether increased metalloproteinase production might be related to the high regional recurrence rate of some carcinomas, and particularly head and neck squamous-cell carcinomas (SCC). Northern blot of total RNA prepared from 26 lung carcinomas, 107 head and neck carcinoma samples and corresponding normal tissue samples demonstrates the frequent and sometimes concomitant over-expression of the 2 stromelysin genes, the type-I collagenase gene and the pump-I gene in the head and neck tumour tissue samples. In these SCC, over-expression of the 2 stromelysin genes and the type-I collagenase gene (but not the pump-I gene) is associated with a high degree of tumour differentiation. Moreover, a tumour with high levels of the stromelysin mRNAs is more likely to show high local invasiveness, suggesting that the stromelysins may be implicated in the clinical course of head and neck tumours. Evaluation of the corresponding mRNA levels may prove a useful indicator for predicting the clinical aggressiveness of these tumours.

Mouse T-cell associated serine proteinase 1 degrades collagen type IV: a structural basis for the migration of lymphocytes through vascular basement membranes

We show that CD8+ T-lymphocyte lines perferentially attach to collagen type IV and that mouse T-cell specific serine proteinase 1 (MTSP-1) preferentially degrades native basement membrane collagen type IV. In contrast, the interstitial collagen types I, II, III, V and VI appear not to be affected. The data reveal that MTSP-1 predominantly cleaves the alpha 2(IV) chain, which is found in the native triple helical structure of type IV collagen in a ratio of alpha 1(IV): alpha 2(IV) = 2:1 into small peptides. The cleavage of the alpha 2(IV) chain within the native collagen type IV molecules most likely results not only in a destabilization of single molecules but of the entire collagenous basement membrane scaffold at the site of MTSP-1 secretion.

Matrix metalloproteinase 2 from human rheumatoid synovial fibroblasts. Purification and activation of the precursor and enzymic properties

Human rheumatoid synovial cells in culture secrete at least three related metalloproteinases that digest extracellular matrix macromolecules. One of them, termed matrix metalloproteinase 2 (MMP-2), has been purified as an inactive zymogen (proMMP-2). The final product is homogeneous on SDS/PAGE with Mr = 72,000 under reducing conditions. The NH2-terminal sequence of proMMP-2 is Ala-Pro-Ser-Pro-Ile-Ile-Lys-Phe-Pro-Gly-Asp-Val-Ala-Pro-Lys-Thr, which is identical to that of the so-called '72-kDa type IV collagenase/gelatinase'. The zymogen can be rapidly activated by 4-aminophenylmercuric acetate to an active form of MMP-2 with Mr = 67,000, and the new NH2-terminal generated is Tyr-Asn-Phe-Phe-Pro-Arg-Lys-Pro-Lys-Trp-Asp-Lys-Asn-Gln-Ile. However, following 4-aminophenylmercuric acetate activation, MMP-2 is gradually inactivated by autolysis. Nine endopeptidases (trypsin, chymotrypsin, plasmin, plasma kallikrein, thrombin, neutrophil elastase, cathepsin G, matrix metalloproteinase 3, and thermolysin) were tested for their abilities to activate proMMP-2, but none had this ability. This contrasts with the proteolytic activation of proMMP-1 (procollagenase) and proMMP-3 (prostromelysin). The optimal activity of MMP-2 against azocoll is around pH 8.5, but about 50% of activity is retained at pH 6.5. Enzymic activity is inhibited by EDTA, 1,10-phenanthroline or tissue inhibitor of metalloproteinases, but not by inhibitors of serine, cysteine or aspartic proteinases. MMP-2 digests gelatin, fibronectin, laminin, and collagen type V, and to a lesser extent type IV collagen, cartilage proteoglycan and elastin. Comparative studies on digestion of collagen types IV and V by MMP-2 and MMP-3 (stromelysin) indicate that MMP-3 degrades type IV collagen more readily than MMP-2, while MMP-2 digests type V collagen effectively. Biosynthetic studies of MMPs using cultured human rheumatoid synovial fibroblasts indicated that the production of both proMMP-1 and proMMP-3 is negligible but it is greatly enhanced by the treatment with rabbit-macrophage-conditioned medium, whereas the synthesis of proMMP-2 is constitutively expressed by these cells and is not significantly affected by the treatment. This suggests that the physiological and/or pathological role of MMP-2 and its site of action may be different from those of MMP-1 and MMP-3.

Tumor necrosis factor bifunctionally regulates matrix metalloproteinases and tissue inhibitor of metalloproteinases (TIMP) production by human fibroblasts

The production of tissue inhibitor of metalloproteinases (TIMP) in human uterine cervical fibroblasts was increased by human recombinant tumor necrosis factor alpha (hrTNF) at a low concentration (0.005 ng/ml) but the elevated synthesis was suppressed in a dose-dependent manner at higher concentrations (up to 50 ng/ml). In contrast, the production of collagenase (EC 3.4.24.7) and stromelysin was stimulated at all the corresponding concentrations. In contrast, human recombinant interleukin-1 alpha (hr IL-1, 10 ng/ml) coordinately induced these enzymes and TIMP production. The reduction of the elevated TIMP production by TNF was not due to the inhibition of TIMP secretion. These results suggest that TNF modulates the extracellular matrix degradation in human fibroblasts bifunctionally by the suppression of TIMP production in addition to the acceleration of matrix metalloproteinases production. Furthermore, the fact that TNF and IL-1 differently controlled the production of TIMP suggests that the signal pathway of TNF for TIMP production is different from that of IL-1.

Tissue inhibitor of metalloproteinases from human bone marrow stromal cell line KM 102 has erythroid-potentiating activity, suggesting its possibly bifunctional role in the hematopoietic microenvironment

In this study, we demonstrated that tissue inhibitor of metalloproteinases (TIMP) produced by human bone marrow stromal cell line KM-102 had erythroid-potentiating activity (EPA) which stimulates the proliferation of erythroid progenitor cells. We, then, propose a scheme for the bifunctional role of TIMP/EPA in hematopoietic microenvironment, that is, the maintenance of the integrity of bone marrow matrix and the proliferation of erythroid progenitor cells proceeding on the matrix.

Connective tissue biology and hepatic fibrosis: report of a conference

The past 15 years have seen major advances in the characterization of extracellular matrix proteins and structure of matrix. As a by-product of this work, investigators now have an array of molecular and immunological reagents for monitoring matrix metabolism. Progress in the isolation and culture of individual cell types from liver has made possible direct measurement of matrix protein production and also has opened the way to studies of matrix degradation. The expanding knowledge of soluble mediators of inflammation is being applied to the regulation of matrix protein synthesis and degradation. Finally, experimental models of fibrosis in vivo are available for defining the complexity of matrix metabolism in the intact tissue and for validating the findings from cell culture and in vitro systems.

Collagenase-like activity associated to the leukemic WEHI-3B cell line

The leukemic cell line, WEHI-3B presents a latent collagenase-like activity which is activated after trypsin treatment. The enzymatic activity is not released from cells and is specific for the degradation of interstitial collagens. After attachment of WEHI cells to a hemopoietic stroma derived from long-term bone marrow cultures, the organization of the stroma is disrupted. This effect was not observed after the attachment to stroma of normal progenitor cells. These results suggest that the collagenase-like activity in leukemic cells may contribute through collagen degradation, to the disorganization of the marrow stroma. The latter was confirmed by the use of a labeled-collagen containing stroma, which was degraded when cocultured with WEHI cells, but not with normal progenitor cells.