Environmental control of mammary carcinoma cell expansion by acidification and spheroid formation in vitro

Breast cancer is the leading cause of cancer death among women worldwide. Like other cancers, mammary carcinoma progression involves acidification of the tumor microenvironment, which is an important factor for cancer detection and treatment strategies. However, the effects of acidity on mammary carcinoma cell morphology and phenotype have not been thoroughly characterized. Here, we evaluated fundamental effects of environmental acidification on mammary carcinoma cells in standard two-dimensional cultures and three-dimensional spheroids. Acidification decreased overall mammary carcinoma cell viability, while increasing their resistance to the anthracycline doxorubicin. Environmental acidification also increased extracellular vesicle production by mammary carcinoma cells. Conditioned media containing these vesicles appeared to increase fibroblast motility. Acidification also increased mammary carcinoma cell motility when cultured with fibroblasts in spheroids. Taken together, results from this study suggest that environmental acidification induces drug resistance and extracellular vesicle production by mammary carcinoma cells that promote tumor expansion.

Multi-gene signature of microcalcification and risk prediction among Taiwanese breast cancer

Microcalcification is one of the most common radiological and pathological features of breast ductal carcinoma in situ (DCIS), and to a lesser extent, invasive ductal carcinoma. We evaluated messenger RNA (mRNA) transcriptional profiles associated with ectopic mammary mineralization. A total of 109 breast cancers were assayed with oligonucleotide microarrays. The associations of mRNA abundance with microcalcifications and relevant clinical features were evaluated. Microcalcifications were present in 86 (79%) patients by pathological examination, and 81 (94%) were with coexistent DCIS, while only 13 (57%) of 23 patients without microcalcification, the invasive diseases were accompanied with DCIS (χ²-test, P < 0.001). There were 69 genes with differential mRNA abundance between breast cancers with and without microcalcifications, and 11 were associated with high-grade (comedo) type DCIS. Enriched Gene Ontology categories included glycosaminoglycan and aminoglycan metabolic processes and protein ubiquitination, indicating an active secretory process. The intersection (18 genes) of microcalcificaion-associated and DCIS-associated genes provided the best predictive accuracy of 82% with Bayesian compound covariate predictor. Ten genes were further selected for prognostic index score construction, and five-year relapse free survival was 91% for low-risk and 83% for high-risk group (log-rank test, P = 0.10). Our study suggested that microcalcification is not only the earliest detectable radiological sign for mammography screening but the phenomenon itself may reflect the underling events during mammary carcinogenesis. Future studies to evaluate the prognostic significance of microcalcifications are warranted.

Role of extra cellular proteins in gastric cancer progression and metastasis: an update

Background

Gastric cancer (GC) is one of the most common cancers in the world with a high ratio of mortality. Regarding the late diagnosis, there is a high ratio of distant metastasis among GC cases. Despite the recent progresses in therapeutic modalities, there is not still an efficient therapeutic method to increase survival rate of metastatic GC cases.

Main body

Apart from the various intracellular signaling pathways which are involved in tumor cell migration and metastasis, the local microenvironment is also a critical regulator of tumor cell migration. Indeed, the intracellular signaling pathways also exert their final metastatic roles through regulation of extra cellular matrix (ECM). Therefore, it is required to assess the role of extra cellular components in biology of GC.

Conclusion

In the present review, we summarize 48 of the significant ECM components including 17 ECM modifying enzymes, seven extracellular angiogenic factors, 13 cell adhesion and cytoskeletal organizers, seven matricellular proteins and growth factors, and four proteoglycans and extra cellular glycoproteins. This review paves the way of determination of a specific extra cellular diagnostic and prognostic panel marker for the GC patients.

Breast Cancer Metastasis: Are Cytokines Important Players During Its Development and Progression?

In breast cancer, an uncontrolled cell proliferation leads to tumor formation and development of a multifactorial disease. Metastasis is a complex process that involves tumor spread to distant parts of the body from its original site. Metastatic dissemination represents the main physiopathology of cancer. Inter- and intracellular communication in all systems in vertebrates is mediated by cytokines, which are highly inducible, secretory proteins, produced not only by immune system cells, but also by endocrine and nervous system cells. It has become clear in recent years that cytokines, as well as their receptors are produced in the organisms under physiological and pathological conditions; recently, they have been closely related to breast cancer metastasis. The exact initiation process of breast cancer metastasis is unknown, although several hypotheses have emerged. In this study, we thoroughly reviewed the role of several cytokines in breast cancer metastasis. Data reviewed suggest that cytokines and growth factors are key players in the breast cancer metastasis induction. This knowledge must be considered with the aim to development of new therapeutic approaches to counter breast cancer metastasis.

Protease-Activated Receptor 1 as Therapeutic Target in Breast, Lung, and Ovarian Cancer: Pepducin Approach

The G-protein coupled receptors (GPCRs) belong to a large family of diverse receptors that are well recognized as pharmacological targets. However, very few of these receptors have been pursued as oncology drug targets. The Protease-activated receptor 1 (PAR1), which is a G-protein coupled receptor, has been shown to act as an oncogene and is an emerging anti-cancer drug target. In this paper, we provide an overview of PAR1’s biased signaling role in metastatic cancers of the breast, lungs, and ovaries and describe the development of PAR1 inhibitors that are currently in clinical use to treat acute coronary syndromes. PAR1 inhibitor PZ-128 is in a Phase II clinical trial and is being developed to prevent ischemic and thrombotic complication of patients undergoing cardiac catheterization. PZ-128 belongs to a new class of cell-penetrating, membrane-tethered peptides named pepducins that are based on the intracellular loops of receptors targeting the receptor G-protein interface. Application of PZ-128 as an anti-metastatic and anti-angiogenic therapeutic agent in breast, lung, and ovarian cancer is being reviewed.

Dental Calculus Stimulates Interleukin-1β Secretion by Activating NLRP3 Inflammasome in Human and Mouse Phagocytes

Dental calculus is a mineralized deposit associated with periodontitis. The bacterial components contained in dental calculus can be recognized by host immune sensors, such as Toll-like receptors (TLRs), and induce transcription of proinflammatory cytokines, such as IL-1β. Studies have shown that cellular uptake of crystalline particles may trigger NLRP3 inflammasome activation, leading to the cleavage of the IL-1β precursor to its mature form. Phagocytosis of dental calculus in the periodontal pocket may therefore lead to the secretion of IL-1β, promoting inflammatory responses in periodontal tissues. However, the capacity of dental calculus to induce IL-1β secretion in human phagocytes has not been explored. To study this, we stimulated human polymorphonuclear leukocytes (PMNs) and peripheral blood mononuclear cells (PBMCs) with dental calculus collected from periodontitis patients, and measured IL-1β secretion by ELISA. We found that calculus induced IL-1β secretion in both human PMNs and PBMCs. Calculus also induced IL-1β in macrophages from wild-type mice, but not in macrophages from NLRP3- and ASC-deficient mice, indicating the involvement of NLRP3 and ASC. IL-1β induction was inhibited by polymyxin B, suggesting that LPS is one of the components of calculus that induces pro-IL-1β transcription. To analyze the effect of the inorganic structure, we baked calculus at 250°C for 1 h. This baked calculus failed to induce pro-IL-1β transcription. However, it did induce IL-1β secretion in lipid A-primed cells, indicating that the crystalline structure of calculus induces inflammasome activation. Furthermore, hydroxyapatite crystals, a component of dental calculus, induced IL-1β in mouse macrophages, and baked calculus induced IL-1β in lipid A-primed human PMNs and PBMCs. These results indicate that dental calculus stimulates IL-1β secretion via NLRP3 inflammasome in human and mouse phagocytes, and that the crystalline structure has a partial role in the activation of NLRP3 inflammasome.

By activating matrix metalloproteinase-7, shear stress promotes chondrosarcoma cell motility, invasion and lung colonization

Interstitial fluid flow and associated shear stress are relevant mechanical signals in cartilage and bone (patho)physiology. However, their effects on chondrosarcoma cell motility, invasion and metastasis have yet to be delineated. Using human SW1353, HS.819.T and CH2879 chondrosarcoma cell lines as model systems, we found that fluid shear stress induces the accumulation of cyclic AMP (cAMP) and interleukin-1β (IL-1β), which in turn markedly enhance chondrosarcoma cell motility and invasion via the induction of matrix metalloproteinase-7 (MMP-7). Specifically, shear-induced cAMP and IL-1β activate PI3-K, ERK1/2 and p38 signaling pathways, which lead to the synthesis of MMP-7 via transactivating NF-κB and c-Jun in human chondrosarcoma cells. Importantly, MMP-7 upregulation in response to shear stress exposure has the ability to promote lung colonization of chondrosarcomas in vivo. These findings offer a better understanding of the mechanisms underlying MMP-7 activation in shear-stimulated chondrosarcoma cells, and provide insights on designing new therapeutic strategies to interfere with chondrosarcoma invasion and metastasis.

The role of cyclooxygenase-2, interleukin-1β and fibroblast growth factor-2 in the activation of matrix metalloproteinase-1 in sheared-chondrocytes and articular cartilage

MMP-1 expression is detected in fluid shear stress (20 dyn/cm²)-activated and osteoarthritic human chondrocytes, however, the precise mechanisms underlying shear-induced MMP-1 synthesis remain unknown. Using primary chondrocytes and T/C-28a2 chondrocytic cells as model systems, we report that prolonged application of high fluid shear to human chondrocytes induced the synthesis of cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β) and fibroblast growth factor-2 (FGF-2), which led to a marked increase in MMP-1 expression. IL-1β, COX-2-dependent PGE₂ activated the PI3-K/AKT and p38 signaling pathways, which were in turn responsible for MMP-1 synthesis via NF-κB- and c-Jun-transactivating pathways. Prolonged shear stress exposure (>12 h) induced 15-Deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) synthesis. Although 15d-PGJ₂ suppressed PI3-K/AKT and p38 signaling pathways, it stimulated MMP-1 expression via activating heme oxygenase 1 (HO-1). The critical role of COX-2 in regulating MMP-1 expression in articular cartilage in vivo was demonstrated using COX-2^+/− transgenic mice in the absence or presence of rofecoxib oral administration. These findings provide novel insights for developing therapeutic strategies to combat OA.

Cytokine-induced monocyte MMP-1 is negatively regulated by GSK-3 through a p38 MAPK-mediated decrease in ERK1/2 MAPK activation

Elucidation of the signal transduction events leading to the production of MMPs by monocytes/macrophages may provide insights into the mechanisms involved in the destruction of connective tissue associated with chronic inflammatory lesions. Here, we show that GSK-3 is a negative regulator of cytokine-induced MMP-1 production by monocytes. Inhibition of monocyte GSK-3 pharmacologically with SB216763 or GSK-3β siRNA caused a significant enhancement of MMP-1 by TNF-α- and GM-CSF-activated monocytes, indicating that induction of MMP-1 by TNF-α and GM-CSF involved phosphorylation/inactivation of GSK-3. TNF-α- and GM-CSF-induced phosphorylation of GSK-3 and subsequent MMP-1 production was blocked with the PKC inhibitor Gö6976 but not by the AKT1/2 inhibitor AKT VIII, showing that cytokine phosphorylation of GSK-3 occurs primarily through a PKC pathway. Inhibition of GSK-3 resulted in decreased phosphorylation of p38 MAPK with a corresponding increase in phosphorylation of ERK1/2 MAPK. Enhanced MMP-1 production by treatment with SB216763 was a result of increased ERK1/2 activation, as demonstrated by inhibition of MMP-1 by PD98059, a specific ERK1/2 inhibitor. Conversely, the p38 MAPK inhibitor SB203580 enhanced cytokine activation of ERK1/2 and the production of MMP-1 similar to that of SB216763. These findings demonstrate that the degree of cytokine-mediated phosphorylation/inhibition of GSK-3 determines the level of MMP-1 production through a mechanism involving decreased activation of p38 MAPK, a negative regulator of ERK1/2 required for cytokine-induced production of MMP-1 by monocytes.

Estrogen receptor beta and truncated variants enhance the expression of transfected MMP-1 promoter constructs in response to specific mechanical loading

Background

Joint diseases such as osteoarthritis (OA) predominantly afflict post-menopausal women, suggesting a pertinent role for female hormones. Estrogen receptor beta (ER-β) has been detected in connective tissues of the knee joint suggesting that these tissues are responsive to the hormone estrogen. Matrix metalloproteinase-1 (MMP-1) activity contributes to cartilage degradation, a key factor leading to OA development in synovial joints. Two polymorphic forms of MMP-1 exist due to a deletion/insertion of the guanine residue in the promoter, and the 2G allelic variant of MMP-1 exhibits more activity than the 1G allele. Previous studies have demonstrated that the polymorphic forms of the human MMP-1 are influenced by the modulating effects of estrogen receptor isoforms. In addition to hormonal influences, physiological factors such as altered mechanical loading are also contributory features of OA. In the present study, the combined influence of biomechanical and hormonal variables on the activity of MMP-1 isoforms was evaluated. We hypothesized that the combined effects of ER-β and sheer stress will differentially activate the two allelic forms of MMP-1 in a hormone-independent manner.

Methods

HIG-82 synoviocytes were transiently transfected with 1G or 2G alleles (±) ER-β and subjected to either shear or equibiaxial stress. Next, 1G/2G promoter activity was measured to determine the combined influence of physiological stimuli. Truncated ER-β constructs were used to determine the importance of different domains of ER-β on 1G/2G activation.

Results

The 2G allele exhibited a constitutively higher activity than the 1G allele, which was further increased when the transfected cells were subject to shear stress, but not equibiaxial stress. Moreover, the combination of ER-β and shear stress further increased the activity levels of the 1G/2G allelic variants. Additionally, select AF-2 truncated ER-β variants led to increased activity levels for the 2G allele, indicating the AF-1 domain was likely involved in the response to mechanical stimulation.

Conclusions

These results suggest that the 1G/2G alleles of MMP-1 are influenced by specific mechanical stimuli like shear stress, as well as the ER-β receptor. These findings contribute to the potential allelic involvement in connective tissue diseases such as OA in females compared to males.

The contribution of the genetic variations of the matrix metalloproteinase-1 gene to the genetic susceptibility of gastric cancer

Matrix metalloproteinase-1 (MMP-1), an interstitial collagenase, is responsible for the proteolytic degradation of basement membrane and extracellular matrix. MMP-1 plays a major role in the invasion of gastric cancer (GC). The role of the genetic polymorphisms in the functional regions of MMP-1 on the risk of GC remains unclear. To identify the markers that contribute to the genetic susceptibility to GC, we examined the potential association between GC and nine single-nucleotide polymorphisms (rs 1799750, rs 498186, rs 475007, rs 514921, rs 494379, rs 996999, rs 2071232, rs 1938901, and rs 2239008) of the MMP-1 gene using the MassARRAY system in this study. The participants enrolled in this study included 422 patients with GC and 428 healthy subjects as the healthy controls from a Chinese Han population. The analysis revealed a weak association between the rs 1799750 (in the promoter region) genotype distribution and GC (p=0.020). The frequency of the 2G allele was significantly higher in the patients with GC than in the healthy controls (p=0.005, odds ratio [OR]=1.324, 95% confidence interval [CI]: 1.087-1.613). Moreover, the patients with the 2G/2G genotype of rs 1799750 had a significantly increased risk of cancer invasion compared with patients with the 1G/1G+1G/2G genotype (p=0.001, OR=0.505, 95% CI: 0.331-0.771). Strong linkage disequilibrium was observed in three blocks (D'>0.9). Significantly, more C-2G haplotypes (block 3) (p=0.0005 after Bonferroni correction) were found in GC subjects. These findings point to a role for MMP-1 promoter polymorphism in GC among a Han Chinese population, and may be informative for future genetic or biological studies on GC.

Involvement of MIF in basement membrane damage in chronically UVB-exposed skin in mice

Solar ultraviolet (UV) B radiation is known to induce matrix metalloproteinases (MMPs) that degrade collagen in the basement membrane. Macrophage migration inhibitory factor (MIF) is a pluripotent cytokine that plays an essential role in the pathophysiology of skin inflammation induced by UV irradiation. This study examined the effects of MIF on basement membrane damage following chronic UVB irradiation in mice. The back skin of MIF transgenic (Tg) and wild-type (WT) mice was exposed to UVB three times a week for 10 weeks. There was a decrease in intact protein levels of type IV collagen and increased basement membrane damage in the exposed skin of the MIF Tg mice compared to that observed in the WT mice. Moreover, the skin of the MIF Tg mice exhibited higher MIF, MMP-2 and MMP-9 expression and protein levels than those observed in the WT mice. We also found that chronic UVB exposure in MIF Tg mice resulted in higher levels of neutrophil infiltration in the dermis compared with that observed in the WT mice. In vitro experiments revealed that MIF induced increases in the MMPs expression, including that of MMP-9 in keratinocytes and MMP-2 in fibroblasts. Cultured neutrophils also secreted MMP-9 stimulated by MIF. Therefore, MIF-mediated basement membrane damage occurs primarily through MMPs activation and neutrophil influx in murine skin following chronic UVB irradiation.

Interleukin-1β and cyclic AMP mediate the invasion of sheared chondrosarcoma cells via a matrix metalloproteinase-1-dependent mechanism

Matrix metalloproteinase-1 (MMP-1) is a potential biomarker for chondrosarcoma that is overexpressed at the invading edges of articular cartilage, and its expression correlates with poor survival rates. However, the molecular mechanisms of MMP-1 regulation and its potential contribution to chondrosarcoma cell invasion have yet to be elucidated, especially in shear-activated cells. Using molecular biology tools and an in vitro fluid shear model, we report that shear stress upregulates cyclic AMP (cAMP) and interleukin-1β (IL-1β) release, which in turn promotes the invasion of chondrosarcoma cells via the induction of MMP-1 in a phosphoinositide 3-kinase (PI3-K)- and ERK1/2-dependent manner. Activated PI3-K and ERK1/2 signaling pathways phosphorylate c-Jun, which in turn transactivates MMP-1 in human chondrosarcoma cells. Collectively, fluid shear stress upregulates matrix MMP-1 expression, which is responsible for the enhanced invasion of human chondrosarcoma cells.

Role of interleukin-1/interleukin-1 receptor antagonist family of cytokines in long-term continuous glucose monitoring in vivo

BACKGROUND

Glucose-sensor-induced tissue reactions (e.g., inflammation and wound healing) are known to negatively impact sensor function in vivo. The roles of cytokine networks in controlling these tissue reactions (i.e., sensor biofouling) is not understood. In the present study, we investigated the role of interleukin-1 receptor antagonist (IL-1Ra), a key anti-inflammatory antagonist of the proinflammatory interleukin-1 cytokines [i.e. interleukin-1 (IL-1) alpha and IL-1 beta] in controlling continuous glucose monitoring (CGM).

METHODS

To investigate the role of IL-1Ra in long-term CGM in vivo, we compared CGM in transgenic mice that overexpress IL-1Ra [interleukin-1 receptor antagonist overexpresser (IL-1Ra~OE), B6.Cg-Tg(IL1rn)1Dih/J] or are deficient in IL-1Ra [interleukin-1 receptor antagonist knockout (IL-1Ra~KO), B6.129S-IL1rn(tm1Dih)/J] with mice that have normal levels of IL-1Ra (C57BL/6) over a 28-day time period.

RESULTS

Mean absolute relative difference (MARD) analysis of CGM results among the mice of varying IL-1Ra levels demonstrated that during the first 21 days, IL-1~KO mice had the greatest tissue inflammation and the poorest sensor performance (i.e., higher MARD values) when compared with normal or IL-1Ra~OE mice. By 28 days post-sensor implantation, the inflammatory reactions had subsided and were replaced by varying degrees of fibrosis.

CONCLUSIONS

These data support our hypothesis on the importance of the IL-1 family of agonists and antagonists in controlling tissue reactions and sensor function in vivo. These data also suggest that local delivery of IL-1Ra genes or recombinant proteins (anakinra) or other IL-1 antagonists such as antibodies or soluble IL-1 receptors would suppress sensor-induced tissue reactions and likely enhance glucose sensor function by inhibiting inflammation and wound healing at sensor implantation sites.

Astrocyte elevated gene-1 is associated with metastasis in head and neck squamous cell carcinoma through p65 phosphorylation and upregulation of MMP1

Background

The survival rate of head and neck squamous cell carcinoma (HNSCC) at advanced stage is poor, despite contemporary advances in treatment modalities. Recent studies have indicated that astrocyte elevated gene-1 (AEG-1), a single transmembrane protein without any known functional domains, is overexpressed in various malignancies and is implicated in both distant metastasis and poor survival.

Results

High expression of AEG-1 in HNSCC was positively correlated with regional lymph node metastasis and a poor 5-year survival rate. Knockdown of AEG-1 in HNSCC cell lines reduced their capacity for colony formation, migration and invasion. Furthermore, decreased tumor volume and metastatic foci were observed after knockdown of AEG-1 in subcutaneous xenografts and pulmonary metastasis assays in vivo, respectively. We also demonstrated that AEG-1 increased phosphorylation of the p65 subunit of NF-κB, and regulated the expression of MMP1 in HNSCC cells. Moreover, compromised phosphorylation of the p65 (RelA) subunit of NF-κB at serine 536 was observed upon silencing of AEG-1 in both HNSCC cell lines and clinical specimens.

Conclusion

High expression of AEG-1 is associated with lymph node metastasis and its potentially associated mechanism is investigated.

Apoptosis signal-regulating kinase 1 is involved in brain-derived neurotrophic factor (BDNF)-enhanced cell motility and matrix metalloproteinase 1 expression in human chondrosarcoma cells

Chondrosarcoma is the primary malignancy of bone that is characterized by a potent capacity to invade locally and cause distant metastasis, and is therefore associated with poor prognoses. Chondrosarcoma further shows a predilection for metastasis to the lungs. The brain-derived neurotrophic factor (BDNF) is a small molecule in the neurotrophin family of growth factors that is associated with the disease status and outcome of cancers. However, the effect of BDNF on cell motility in human chondrosarcoma cells is mostly unknown. Here, we found that human chondrosarcoma cell lines had significantly higher cell motility and BDNF expression compared to normal chondrocytes. We also found that BDNF increased cell motility and expression of matrix metalloproteinase-1 (MMP-1) in human chondrosarcoma cells. BDNF-mediated cell motility and MMP-1 up-regulation were attenuated by Trk inhibitor (K252a), ASK1 inhibitor (thioredoxin), JNK inhibitor (SP600125), and p38 inhibitor (SB203580). Furthermore, BDNF also promoted Sp1 activation. Our results indicate that BDNF enhances the migration and invasion activity of chondrosarcoma cells by increasing MMP-1 expression through a signal transduction pathway that involves the TrkB receptor, ASK1, JNK/p38, and Sp1. BDNF thus represents a promising new target for treating chondrosarcoma metastasis.

Matrix metalloproteinase-1 mitral expression and -1607 1G/2G gene promoter polymorphism in mitral chordae tendinae rupture

Understanding the pathogenesis of mitral chordae tendinae rupture (MCTR) is essential for identification of risk factors. Mitral matrix metalloproteinase (MMP) triggers the signal cascade that instigates cardiac fibrosis, which may be a predisposing factor in MCTR. We investigated associations among MMP1 expression, MMP1 -1607 1G/2G polymorphism and mitral chordae tendinae rupture (MCTR). This study enrolled 185 patients (group A) receiving mitral valve replacement. Group A included 65 patients with MCTR and 120 controls without MCTR. MMP1 was assessed on a semiquantitative scale (0-3) by immunohistochemical staining. For genetic association study, another 227 subjects were recruited for group B, including 75 with MCTR and 152 controls. The gene polymorphisms were analyzed by polymerase chain reaction. In group A, MCTR patients had a higher MMP1 expression compared to controls (P < 0.001). Binary regression analysis showed the variation in the MCTR patients was independently explained by MMP1 (P = 0.027). Hypertension and MMP1 staining had a synergistic effect on the MCTR occurrence (P < 0.001). In group B, MMP1 -1607 1G allele was increased in patients with MCTR compared to controls (P = 0.014). The odds ratio for the 1G/1G genotype to the 2G/2G genotype was 3.22 (P = 0.009). Univariate and logistic regression analysis showed an independent association between MCTR and MMP1 -1607 1G/2G polymorphism (P = 0.028 and 0.032, respectively). Since MMP1 mitral expression and -1607 1G/2G polymorphism were associated with MCTR independently of other baseline characteristics, MMP1 may play a role in the individual susceptibility to MCTR.

Interaction between the elastin peptide VGVAPG and human elastin binding protein

The elastin binding protein (EBP), a spliced variant of lysosomal β-galactosidase, is the primary receptor of elastin peptides that have been linked to emphysema, aneurysm and cancer progression. The sequences recognized by EBP share the XGXXPG consensus pattern found in numerous matrix proteins, notably in elastin where the VGVAPG motif is repeated. To delineate the elastin binding site of human EBP, we built a homology model of this protein and docked VGVAPG on its surface. Analysis of this model suggested that Gln-97 and Asp-98 were required for interaction with VGVAPG because they contribute to the definition of a pocket thought to represent the elastin binding site of EBP. Additionally, we proposed that Leu-103, Arg-107, and Glu-137 were essential residues because they could interact with VGVAPG itself. Site-directed mutagenesis experiments at these key positions validated our model. This work therefore provides the first structural data concerning the interaction of the VGVAPG with its cognate receptor. The present structural data should now allow the development of EBP-specific antagonists.

Influence of single nucleotide polymorphisms in the MMP1 promoter region on cutaneous melanoma progression

Recently, we reported on the associations of seven single nucleotide polymorphisms (SNPs) in the promoter region of MMP1 gene with susceptibility to cutaneous melanoma (CM). Considering the reported correlation between MMP1 expression and melanoma progression, we hypothesized that these promoter SNPs might affect CM progression and prognosis. In this study, we examined the associations of seven SNPs with overall survival, as well as six clinicopathological factors in 754 patients with CM. After adjustment for 11 covariates, we observed significant associations of the SNP -422A>T (rs475007) with ulceration status (P=0.012), primary tumor thickness (P=0.040), and anatomic site (P=0.030). We also observed significant associations of the SNP -755T>G (rs498186) with ulceration status (P=0.038) and anatomic site (P=0.003). Two SNPs, -839G>A and -519A>G, were marginally associated with primary tumor thickness, ulceration status, and anatomic site. Furthermore, the frequency of haplotype 2G-G-G-A-A-G-T was higher in patients with ulceration (odds ratio=2.18, 95% confidence interval: 1.08-4.40, P=0.030) compared with those without ulceration. However, we did not find significant associations of these SNPs with overall survival and other clinical factors. As primary tumor thickness and ulceration status are two important indicators of tumor progression and have significant associations with melanoma prognosis, our results suggested that these promoter SNPs in MMP1 might have potential effects on melanoma progression and prognosis by influencing related clinical factors.

Activation of Akt leading to NF-κB up-regulation in chondrocytes stimulated with fibronectin fragment

Increased fibronectin fragments are thought to contribute to joint destruction in osteoarthritis (OA). However, the mechanism whereby fibronectin fragments cause catabolic activities is not totally understood. While COOH-terminal heparin-binding fibronectin fragment (HBFN-f) has been shown to activate nuclear factor (NF)-κB pathway, intracellular upstream events that cause NF-κB up-regulation in response to HBFN-f remain unclear. Thus, this study was aimed to elucidate the involvement of phosphoinositide-3-OH kinase (PI3K)/Akt pathway in NF-κB activation by HBFN-f in OA chondrocytes. In chondrocyte monolayer cultures, HBFN-f stimulated nitric oxide (NO) production in association with phosphorylation of NF-κB and Akt. Inhibition studies using LY294002 revealed the requirement of PI3K/Akt pathway for NO production and NF-κB activation by HBFN-f. Anti-CD44 treatment with anti-CD44 antibody and hyaluronan resulted in significant inhibition of HBFN-f actions on NO, NF-κB, and Akt. Herein, we provided the first evidence that HBFN-f activates PI3K/Akt pathway leading to up-regulation of NF-κB through interaction with CD44.

STAT3, p38 MAPK, and NF-kappaB drive unopposed monocyte-dependent fibroblast MMP-1 secretion in tuberculosis

Tissue destruction characterizes infection with Mycobacterium tuberculosis (Mtb). Type I collagen provides the lung's tensile strength, is extremely resistant to degradation, but is cleaved by matrix metalloproteinase (MMP)-1. Fibroblasts potentially secrete quantitatively more MMP-1 than other lung cells. We investigated mechanisms regulating Mtb-induced collagenolytic activity in fibroblasts in vitro and in patients. Lung fibroblasts were stimulated with conditioned media from Mtb-infected monocytes (CoMTb). CoMTb induced sustained increased MMP-1 (74 versus 16 ng/ml) and decreased tissue inhibitor of metalloproteinase (TIMP)-1 (8.6 versus 22.3 ng/ml) protein secretion. CoMTb induced a 2.7-fold increase in MMP-1 promoter activation and a 2.5-fold reduction in TIMP-1 promoter activation at 24 hours (P = 0.01). Consistent with this, TIMP-1 did not co-localize with fibroblasts in patient granulomas. MMP-1 up-regulation and TIMP-1 down-regulation were p38 (but not extracellular signal-regulated kinase or c-Jun N-terminal kinase) mitogen-activated protein kinase-dependent. STAT3 phosphorylation was detected in fibroblasts in vitro and in tuberculous granulomas. STAT3 inhibition reduced fibroblast MMP-1 secretion by 60% (P = 0.046). Deletion of the MMP-1 promoter NF-κB-binding site abrogated promoter induction in response to CoMTb. TNF-α, IL-1β, or Oncostatin M inhibition in CoMTb decreased MMP-1 secretion by 65, 63, and 25%, respectively. This cytokine cocktail activated the same signaling pathways in fibroblasts and induced MMP-1 secretion similar to that induced by CoMTb. This study demonstrates in a cellular model and in patients with tuberculosis that in addition to p38 and NF-κB, STAT3 has a key role in driving fibroblast-dependent unopposed MMP-1 production that may be key in tissue destruction in patients.

Importance of interleukin-1 and interleukin-1 receptor antagonist in short-term glucose sensor function in vivo

BACKGROUND

The importance of the interleukin (IL)-1 cytokine family in inflammation and immunity is well established as a result of extensive in vitro and in vivo studies. In fact, much of our understanding of the in vivo importance of interleukin-1beta (IL-1B) is the result of research utilizing transgenic mice, such as overexpression or deficiencies of the naturally occurring inhibitor of IL-1 known as interleukin-1 receptor antagonist (IL-1RA). For the present studies, we utilized these transgenic mice to determine the role of IL-1B in glucose sensor function in vivo.

METHODS

To investigate the role of IL-1B in glucose sensor function in vivo, we compared glucose sensor function in trans-genic mice that (1) overexpressed IL-1RA [B6.Cg-Tg(II1rn)1Dih/J] and (2) are deficient in IL-1RA (B6.129S-Il1rn(tm1Dih)/J), with mice that have normal levels of IL-1RA (C57BL/6).

RESULTS

Our studies demonstrated that, during the first 7 days post-sensor implantation (PSI), mice deficient in IL-1RA had extensive inflammation and decreased sensor function when compared to normal or IL-1RA-overexpressing mice.

CONCLUSION

These data directly support our hypothesis that the IL-1 family of cytokines and antagonists play a critical role in controlling tissue reactions and thereby sensor function in vivo during the first 7 days PSI.

Mycobacterium tuberculosis upregulates microglial matrix metalloproteinase-1 and -3 expression and secretion via NF-kappaB- and Activator Protein-1-dependent monocyte networks

Inflammatory tissue destruction is central to pathology in CNS tuberculosis (TB). We hypothesized that microglial-derived matrix metalloproteinases (MMPs) have a key role in driving such damage. Analysis of all of the MMPs demonstrated that conditioned medium from Mycobacterium tuberculosis-infected human monocytes (CoMTb) stimulated greater MMP-1, -3, and -9 gene expression in human microglial cells than direct infection. In patients with CNS TB, MMP-1/-3 immunoreactivity was demonstrated in the center of brain granulomas. Concurrently, CoMTb decreased expression of the inhibitors, tissue inhibitor of metalloproteinase-2, -3, and -4. MMP-1/-3 secretion was significantly inhibited by dexamethasone, which reduces mortality in CNS TB. Surface-enhanced laser desorption ionization time-of-flight analysis of CoMTb showed that TNF-alpha and IL-1beta are necessary but not sufficient for upregulating MMP-1 secretion and act synergistically to drive MMP-3 secretion. Chemical inhibition and promoter-reporter analyses showed that NF-kappaB and AP-1 c-Jun/FosB heterodimers regulate CoMTb-induced MMP-1/-3 secretion. Furthermore, NF-kappaB p65 and AP-1 c-Jun subunits were upregulated in biopsy granulomas from patients with cerebral TB. In summary, functionally unopposed, network-dependent microglial MMP-1/-3 gene expression and secretion regulated by NF-kappaB and AP-1 subunits were demonstrated in vitro and, for the first time, in CNS TB patients. Dexamethasone suppression of MMP-1/-3 gene expression provides a novel mechanism explaining the benefit of steroid therapy in these patients.

Enhanced endothelial cell senescence by lithium-induced matrix metalloproteinase-1 expression

Endothelial cell (EC) senescence and dysfunction occurring after chronic injury and inflammation are highly associated with the development and progression of cardiovascular diseases. However, the factors involved in the establishment of EC senescence remain poorly understood. We have previously shown that lithium, an inhibitor of glycogen synthase kinase (GSK)-3beta and activator of the Wnt/beta-catenin signaling pathway, induces an EC senescent-like phenotype. Herein, we show that lithium induces a rapid and pronounced up-regulation of the matrix metalloproteinase (MMP)-1, an inflammation and senescent cell marker, at the mRNA and protein levels, whereas the induction of two other senescent cell markers is either weak (interleukin-8) or delayed (plasminogen activator inhibitor-1). Lithium effect on MMP-1 expression is also specific among other MMPs and not mediated by GSK3beta inhibition. Lithium affects MMP-1 expression mainly at the transcriptional level but neither the AP1/Ets regulatory sites nor the redox sensitive (-1607/2G) site in MMP-1 promoter are involved in lithium-dependent MMP-1 regulation. However, down-regulation of p53, a target of lithium in EC, dampens both basal and lithium-induced MMP-1 expression, which further links MMP-1 up-regulation with the establishment of cell senescence. Although increased MMP-1 levels are usually associated with angiogenesis in enabled proliferative EC, the exogenous addition of activated MMP-1 on lithium- arrested EC increases the number of EC positive for the senescent-associated-beta-galactosidase marker. Conversely, down-regulation of MMP-1 expression by small interfering RNAs blunts the lithium-dependent increase in senescent-associated-beta-galactosidase positive cells. Altogether our data indicate that lithium-induced MMP-1 may participate in the reinforcement of EC senescence and reveal a novel mechanism for lithium-induced tissue remodeling.

MMP-1 polymorphisms and the risk of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrotic lung disorder of unknown etiology and unclear pathogenesis. Matrix metalloproteinase-1 (MMP-1) is strongly upregulated and may contribute to the abnormal remodeling that characterizes the disease. We conducted a case-control study of 130 IPF patients and 305 healthy controls to investigate associations between two polymorphisms of the MMP-1 gene promoter and IPF risk. First, using PCR-restriction fragment length polymorphism (PCR-RFLP) analysis we studied the 2G polymorphism at -1,607, shown previously to generate the core of an AP-1 binding site and correlate with high transcriptional activity and risk for IPF. The frequency of the 2G/2G genotype was higher in IPF than in controls (63 vs. 49%; P < 0.008; OR = 1.7; CI 1.15-2.79). Next, we studied a T/G SNP at position -755, which we identified by sequencing the MMP-1 promoter. Chromatin immunoprecipitation (ChIP) assay performed on IPF fibroblasts with either -755 genotype revealed an AP-1 binding site for TT(-755) and GT(-755) genotypes. The frequency of this SNP revealed no significant differences between IPF and healthy controls. However, when the study individuals were stratified by their smoking status, a significant increase in the T/T genotype frequency was observed in smoking cases compared with smoking controls (45 vs. 26%; P = 0.03; OR = 2.3; CI 1.15-4.97). These findings indicate that polymorphisms of the MMP-1 promoter may confer increased risk for IPF and reveal a putative gene-environment interaction between the -755 MMP-1 polymorphism and smoking in this disease.

Hyaluronan inhibits IL-1beta-stimulated collagenase production via down-regulation of phosphorylated p38 in SW-1353 human chondrosarcoma cells

We investigated the intracellular mechanism for the inhibitory effects of hyaluronan (HA) on interleukin-1beta (IL-1beta)-stimulated collagenase-1 and -3 (matrix metalloproteinases (MMPs)-1 and -13) production in a human chondrosarcoma cell line, SW-1353. MMPs-1 and -13 were induced by IL-1beta at 2 ng/ml in SW-1353 cells for 48 h. HA of 800 kDa, which is used clinically, significantly suppressed IL-1beta-stimulated production of MMPs-1 and -13 by immunoblotting. SW-1353 cells express the standard form of CD44 (CD44H), and immunofluorescent cytochemistry demonstrated the association of HA with CD44 on SW-1353 cells. Phosphorylated p38 (Phos-p38) mitogen-activated protein kinase was stimulated in SW-1353 cells by IL-1beta but not by HA alone. SB203580, a p38 MAPK inhibitor, partially blocked the MMP-1 and -13 production stimulated by IL-1beta. 800-kDa HA suppressed IL-1beta-activated Phos-p38 in a dose-dependent manner. CD44 blocking significantly reversed the inhibitory effects of HA on IL-1beta-activated Phos-p38 production. The present study clearly suggests that HA binds CD44 and inhibits IL-1beta-induced MMP-1 and -13 expression via down-regulation of Phos-p38 in SW-1353 cells.

Polymorphisms in the promoter regions for human MMP-1 and MMP-13 lead to differential responses to the alpha and beta isoforms of estrogen receptor and their ligand in vitro

Estrogen receptors (ER) are present in connective tissues and therefore it is possible that the loss of estrogen after menopause influences the integrity of these tissues, contributing to development of degenerative conditions such as osteoporosis and osteoarthritis in a subset of women. Aberrant expression of matrix metalloproteinases (e.g. MMP-1 and MMP-13) has been implicated in the progression of these diseases. The present study investigated potential molecular mechanisms involved in the regulation of expression of MMP-1 and MMP-13 promoter variants by ER-alpha and ER-beta (+/-estrogen) in a transient transfection system. The results demonstrate that the activity of human MMP-1 and MMP-13 polymorphic variants is elevated in the presence of ER-alpha and ER-beta, and the single nucleotide polymorphisms present in the promoters of MMP-1 and MMP-13 variants leads to differential activities in response to the ER isoforms. Furthermore, the influence of 17-beta estradiol also varies depending upon whether the alpha or the beta isoform of ER is the modulator of these polymorphic variants. These findings support the conclusion that ER isoforms may be contributing to disease development and/or progression in genetically distinct subsets of women following menopause, and provide mechanistic insights into how such contributions are manifested.

Interleukin-1beta and macrophage migration inhibitory factor (MIF) in dermal fibroblasts mediate UVA-induced matrix metalloproteinase-1 expression

BACKGROUND

Exposure to solar UV radiation is the main environmental factor that causes premature aging of the skin. Matrix metalloproteinases (MMP)-1 is a member of the MMP family and degrades types I and III collagens, which are the major structural components of the dermis.

OBJECTIVE

We evaluated the involvement IL-1beta and macrophage migration inhibitory factor (MIF) in MMP-1 expression under ultraviolet A (UVA) irradiation.

METHODS

IL-1beta and MIF in MMP-1 expression in cultured human dermal fibroblasts and the UVA effects on MMPs production using IL-1alpha/beta-deficient mice were analyzed. Furthermore, fibroblasts derived from MIF-deficient mice were used to analyze the effect of IL-1beta-induced MMPs production.

RESULTS

IL-1beta-enhanced MIF expression and induced MMP-1 in cultured human dermal fibroblasts. IL-1beta-induced MMP-1 expression is inhibited by neutralizing anti-MIF antibody. Dermal fibroblasts of IL-1alpha/beta-deficient mice produced significantly decreased levels of MMPs compared to wild-type mice after UVA irradiation. Furthermore, fibroblasts of MIF-deficient mice were much less sensitive to IL-1beta-induced MMPs production. On the contrary, IL-1beta produced significantly decreased levels of MMPs in MIF-deficient mice fibroblasts. The up-regulation of MMP-1 mRNA by IL-1beta stimulation was found to be inhibited by a p38 inhibitor and a JNK inhibitor. In contrast, the MEK inhibitor and inhibitor were found to have little effect on expression of MMP-1 mRNA.

CONCLUSIONS

IL-1beta is involved in the up-regulation of UVA-induced MMP-1 in dermal fibroblasts, and IL-1beta and MIF cytokine network induce MMP-1 and contribute to the loss of interstitial collagen in skin photoaging.

Inhibition of nuclear factor-kappaB by hyaluronan in rheumatoid chondrocytes stimulated with COOH-terminal heparin-binding fibronectin fragment

The aim of this study was to examine the inhibitory effect of high molecular weight hyaluronan (HA) on nuclear factor (NF)-kappaB activation by COOH-terminal heparin-binding fibronectin fragment (HBFN-f) in rheumatoid arthritis (RA) chondrocytes. When RA chondrocytes in monolayer or cartilage explants were cultured with HBFN-f, the fragment stimulated the phosphorylation and nuclear translocation of NF-kappaB, leading to nitric oxide (NO) production in association with inducible form of NO synthase (iNOS) up-regulation. Inhibition studies with NF-kappaB inhibitors indicated the requirement of NF-kappaB for HBFN-f-induced NO production. Pretreatment with 2700 kDa HA resulted in significant suppression of NF-kappaB activation by HBFN-f. HA also inhibited HBFN-f-stimulated NO production with down-regulation of iNOS. The present study clearly demonstrated that high molecular weight HA suppressed HBFN-f-activated NF-kappaB in RA chondrocytes. HA could down-regulate the catabolic action of fibronectin fragments like HBFN-f in RA joints as a potent NF-kappaB inhibitor.

Transient receptor potential vanilloid-1 mediates heat-shock-induced matrix metalloproteinase-1 expression in human epidermal keratinocytes

Transient receptor potential vanilloid-1 (TRPV1), a heat-gated channel, was recently found on human keratinocytes and the activation of epidermal TRPV1 was known to induce release of proinflammatory mediators. However, the functional consequences of TRPV1 activation in cutaneous physiology and pathology have not been elucidated clearly. In this study, we investigated the role of TRPV1 on the matrix metalloproteinase (MMP)-1 expression induced by heat shock in human epidermal keratinocytes. Heat shock induced the expression of MMP-1 mRNA and protein in a temperature-dependent manner in an immortalized human keratinocyte cell line (HaCaT) and normal human epidermal keratinocytes (NHK). Heat-shock-induced MMP-1 expression was decreased by treatment of the TRPV1 inhibitors (capsazepine and ruthenium red) or knockdown of TRPV1 using RNA interference in HaCaT cells. Overexpression of TRPV1 greatly increased heat-shock-induced MMP-1 promoter activity in HEK 293 cells. Furthermore, direct activation of TRPV1 by capsaicin, a TRPV1 agonist, increased MMP-1 expression. We found that heat shock induced calcium influx through TRPV1 and that extracellular calcium was necessary for heat-shock-induced MMP-1 expression in HaCaT cells. Taken together, our results suggest that heat-shock-induced MMP-1 expression is mediated by activation of TRPV1 and is dependent on a calcium-dependent signaling process in human epidermal keratinocytes.

Regulation of matrix metalloproteinase gene expression by a retinoid X receptor-specific ligand

OBJECTIVE

To evaluate the effects of LG100268 (LG268), a synthetic ligand for the nuclear hormone receptor retinoid X receptor, on the expression of matrix metalloproteinase 1 (MMP-1) and MMP-13 induced by proinflammatory cytokines in a chondrocyte model.

METHODS

SW-1353 human chondrosarcoma cells were used to study the effects of LG268 on interleukin-1beta (IL-1beta)-stimulated MMP production and collagen degradation. Gene expression was determined by quantitative real-time reverse transcription-polymerase chain reaction, and protein levels were determined by Western blot analysis. Collagen degradation was determined by an in vitro matrix destruction assay. The effects of LG268 on nuclear protein binding and histone acetylation were determined by electrophoretic mobility shift assay and chromatin immunoprecipitation assay, respectively.

RESULTS

LG268 treatment specifically antagonized the IL-1beta-mediated induction of MMP-1 and MMP-13 heterogeneous nuclear RNA, messenger RNA, and protein. The inhibitory effect of LG268 was found to be due to a decrease in the rate of MMP-1 and MMP-13 transcription. LG268 treatment also prevented the in vitro degradation of a type I collagen matrix by IL-1beta-treated SW-1353 cells. The inhibitory effect of LG268 on MMP-1 and MMP-13 transcription appears to be mediated, at least in part, through modulation of histone modification in regions of the MMP-1 and MMP-13 promoters that contain binding sites for activator protein 1 transcription factors.

CONCLUSION

These data indicate that LG268 treatment selectively inhibits inflammatory cytokine-induced production of MMP-1 and MMP-13 at the level of gene transcription and blocks collagen destruction by proinflammatory cytokine-stimulated chondrocytic cells. This study is among the first to describe how rexinoids affect gene expression, and the findings suggest that the rexinoid class of compounds may have a future role in preventing the irreversible collagen destruction seen in the arthritides.

RelA is required for IL-1beta stimulation of Matrix Metalloproteinase-1 expression in chondrocytes

OBJECTIVE

Interleukin-1beta (IL-1beta) stimulates collagenase-1 (Matrix Metalloproteinase-1 (MMP-1)) expression in articular chondrocytes, leading to cleavage of type II collagen and irreversible cartilage degradation. The nuclear factor-kappa B (NF-kappaB) pathway is potently activated in IL-1beta-stimulated cells and has been implicated as an intermediate in MMP-1 gene expression. However, the roles of individual NF-kappaB family members during IL-1beta-induced MMP-1 gene expression have not been defined.

RESULTS

To address the relationship between the NF-kappaB pathway and MMP-1 gene activation in chondrocytes, primary cultured human articular chondrocyte cultures (HAC) and SW-1353 cells were stimulated with IL-1beta over a 24-h time course and MMP-1, NF-kappaB1, NF-kappaB2 and RelA gene expression was assayed. IL-1beta-induced MMP-1 expression was comparable in HAC and SW-1353 cells both temporally and quantitatively. MMP-1 gene expression was mirrored by increases in NF-kappaB gene expression, and inhibition of NF-kappaB nuclear translocation with dominant-negative IkappaBalpha reduced IL-1beta-dependent MMP-1 gene expression. IL-1beta activated the NF-kappaB pathway in chondrocytes, both through phosphorylation and transient degradation of IkappaBalpha, as well as through sustained phosphorylation of RelA. Small inhibitory RNAs (siRNA) specific for RelA resulted in significant reduction of MMP-1 mRNA, whereas siRNA for NF-kappaB1 and NF-kappaB2 augmented IL-1beta-induced MMP-1 expression.

CONCLUSIONS

Our data demonstrate that IL-1beta activation of the NF-kappaB pathway is required for IL-1beta induction of MMP-1 in chondrocytes and that RelA can work independently of NF-kappaB1 or NF-kappaB2 to activate this gene expression program.

The elastin receptor complex transduces signals through the catalytic activity of its Neu-1 subunit

The binding of elastin peptides on the elastin receptor complex leads to the formation of intracellular signals but how this is achieved remains totally unknown. Using pharmacological inhibitors of the enzymatic activities of its subunits, we show here that the elastin peptide-driven ERK1/2 activation and subsequent pro-MMP-1 production, observed in skin fibroblasts when they are cultured in the presence of these peptides, rely on a membrane-bound sialidase activity. As lactose blocked this effect, the elastin receptor sialidase subunit, Neu-1, seemed to be involved. The use of a catalytically inactive form of Neu-1 and the small interfering RNA-mediated decrease of Neu-1 expression strongly support this view. Finally, we report that N-acetyl neuraminic acid can reproduce the effects of elastin peptides on both ERK1/2 activation and pro-MMP-1 production. Altogether, our results indicate that the enzymatic activity of the Neu-1 subunit of the elastin receptor complex is responsible for its signal transduction, presumably through sialic acid generation from undetermined substrates.

The collagenase-1 (MMP-1) gene promoter polymorphism - 1607/2G is associated with favourable prognosis in patients with colorectal cancer

Matrix metalloproteinase (MMP) overexpression has been implicated in the pathogenesis of colorectal carcinoma (CRC). Accumulating evidence suggests that MMP promoter single nucleotide polymorphisms (SNPs) effecting gene transcription are associated with enhanced susceptibility for the development of malignant disease, increased tumour invasiveness and poor patient survival. The aim of the current investigation was to determine whether such associations exist in a large CRC patient/control study population. Using an allelic discrimination real-time polymerase chain reaction, polymorphisms in the MMP-1, MMP-2 and MMP-3 gene promoters (−1607, −1306, and −1612 bp, respectively) were assessed in normal blood mononuclear cells from patients with CRC (n=503) and control subjects (n=471). Genotypes corresponding to each MMP SNP were correlated with tumour characteristics and clinical outcome. The frequency of each genotype was not statistically different between patients and control subjects and no significant differences were noted between the genotypes and tumour characteristics for the three MMP SNPs. CRC patients with the 2G/2G genotype for the MMP-1 SNP had significantly better 5-year survival compared to patients with a 1G allele (P<0.05). Our results demonstrate that CRC patients with a 2G/2G genotype in the MMP-1 gene promoter SNP have a favourable prognosis. Although our results were unexpected, given that this genotype is associated with enhanced MMP-1 transcriptional activity, they are consistent with recent data highlighting the anti-tumorigenic properties of MMPs.

Transcriptional repression of matrix metalloproteinase gene expression by the orphan nuclear receptor NURR1 in cartilage

The NR4A orphan receptors (Nur77, NURR1, and NOR-1) are emerging as key regulators of cytokine and growth factor action in chronic inflammatory diseases. In this study, we address the role of these receptors in cartilage homeostasis during inflammatory joint disease. We document for the first time expression of the NR4A receptors in osteoarthritic cartilage. Relative to Nur77 and NOR-1, NURR1 is expressed at the highest level and correlates with cyclooxygenase-2 levels in cartilage. Consistent with this observation, cyclooxygenase-2-derived prostaglandin E(2) (PGE(2)) rapidly and potently induces NURR1 expression in chondrocytes, suggesting that this receptor may regulate PGE(2)-mediated processes in cartilage. We demonstrate that PGE(2) represses interleukin-1beta-induced matrix metalloproteinase (MMP)-1 and that transient overexpression of NURR1 is sufficient to antagonize expression of this gene. Furthermore, MMP-1 promoter activity is potently suppressed by NURR1, resulting in a significant reduction in endogenous MMP-1 mRNA and secreted pro-MMP-1 protein. In addition, NURR1 selectively antagonizes cytokine-induced MMP-3 and -9 expression with minimal effects on MMP-2 and -13 and tissue inhibitor of matrix metalloproteinases-1 and -2. To explore the molecular mechanisms of NURR1 transrepression, we reveal that this receptor targets a critical region of the MMP-1 promoter (-1772 to -1546 bp) and that repression does not require consensus binding sites for NURR1. We confirm that NURR1 targets a 40-bp promoter sequence that is also positively regulated by ETS transcription factors. Finally, functional studies indicate that transcriptional antagonism exists between NURR1 and ETS1 on the MMP-1 promoter. We propose a protective function for NURR1 in cartilage homeostasis by selectively repressing MMP gene expression during inflammation.

Leptin represses matrix metalloproteinase-1 gene expression in LX2 human hepatic stellate cells

BACKGROUND/AIMS

Collagen accumulation in liver fibrosis is due in part to decreased expression of matrix metalloproteinase (MMP)-1 relative to TIMP-1. LX-2 hepatic stellate cells produce increased amounts of collagen and tissue inhibitor of metalloproteinase (TIMP)-1 in response to leptin. The effect of leptin on MMP-1 production has not been reported.

METHODS

LX-2 cells were treated with leptin with or without inhibitors. We determined: phosphorylation of Janus kinase (JAK) 1 and -2, signal transducer and activator of transcription (STAT)3 and -5, extracellular signal-regulated kinase (ERK)1/2 and p38 by Western blot; H2O2 concentration by a colorimetric method; MMP-1 mRNA levels and stability by Northern blot; MMP-1 promoter activity as well as pro-MMP-1 by ELISA; and active MMP-1 by fluorescence.

RESULTS

LX-2 cells constitutively expressed the MMP-1 gene and leptin repressed the basal level of MMP-1 mRNA and its promoter activity. The repression was mediated by JAK/STAT pathway in synergism with JAK-mediated H2O2-dependent ERK1/2 and p38 pathways. ERK1/2 inhibited MMP-1 promoter activity, whereas p38 decreased the message stability, contributing to mRNA down-regulation. Inhibition of MMP-1 gene diminished secreted pro-MMP-1 and active MMP-1.

CONCLUSIONS

Leptin represses MMP-1 gene expression via the synergistic actions of the JAK/STAT pathway and JAK-mediated H2O2-dependent ERK1/2 and p38 pathways.

Cartilage destruction by matrix degradation products

The progressive destruction of articular cartilage is one of the hallmarks of osteoarthritis and rheumatoid arthritis. Cartilage degradation is attributed to different classes of catabolic factors, including proinflammatory cytokines, aggrecanases, matrix metalloproteinases, and nitric oxide. Recently, matrix degradation products generated by excessive proteolysis in arthritis have been found to mediate cartilage destruction. These proteolytic fragments activate chondrocytes and synovial fibroblasts via specific cell surface receptors that can stimulate catabolic intracellular signaling pathways, leading to the induction of such catalysts. This review describes the catabolic activities of matrix degradation products, especially fibronectin fragments, and discusses the pathologic implication in cartilage destruction in osteoarthritis and rheumatoid arthritis. Increased levels of these degradation products, found in diseased joints, may stimulate cartilage breakdown by mechanisms of the kind demonstrated in the review.

Identification in human osteoarthritic chondrocytes of proteins binding to the novel regulatory site AGRE in the human matrix metalloprotease 13 proximal promoter

OBJECTIVE

Matrix metalloprotease 13 (MMP-13) plays a major role in osteoarthritic (OA) processes. We previously identified the AG-rich element (AGRE) regulatory site (GAAAAGAAAAAG) in the proximal promoter of this gene. Electrophoretic mobility shift assays (EMSAs) done with nuclear extracts from OA chondrocytes showed the presence of 2 AGRE protein-binding complexes, the formation of which depended on the pathophysiologic state (high or low) of the cells; the low OA (L-OA) chondrocytes have low MMP-13 basal levels and high interleukin-1beta (IL-1beta) inducibility, and the high OA (H-OA) chondrocytes have high MMP-13 basal levels and low IL-1beta inducibility. In this study, we sought to determine the importance of individual AGRE bases in promoter activity and to identify AGRE binding proteins from L-OA and H-OA chondrocyte complexes.

METHODS

Promoter activity was determined following transient transfection into human OA chondrocytes. AGRE binding proteins were identified by mass spectroscopy.

RESULTS

Individual mutations of the AGRE site differentially modulated promoter activity, indicating that the intact AGRE site is required for optimal MMP-13 expression. Damage-specific DNA binding protein 1 (DDB-1) was identified in the L-OA chondrocyte-binding complex. EMSA experiments performed with the mutation of the left AGRE site (GTGCTGAAAAAG) and nuclear extracts of L-OA chondrocytes reproduced the pattern seen in the H-OA chondrocytes. Mass spectroscopy identified p130cas as one of the proteins in this complex. Supershift experiments showed the presence of p130cas and nuclear matrix transcription factor 4 (NMP-4) in the wild-type AGRE/H-OA chondrocyte complex.

CONCLUSION

These data suggest that the binding of p130(cas) and NMP-4 to the AGRE site regulates MMP-13 expression and may trigger the change in human chondrocytes from the L-OA state to the H-OA state.

Differential regulation of cytokine-induced MMP-1 and MMP-13 expression by p38 kinase inhibitors in human chondrosarcoma cells: potential role of Runx2 in mediating p38 effects

OBJECTIVE

To investigate mitogen activated protein (MAP) kinase pathways for their ability to differentially regulate the expression of matrix metalloprotease (MMP)-1 and -13 in human chondrosarcoma cells using pathway-selective inhibitors.

DESIGN

Human chondrosarcoma cell lines (SW1353 and JJ012) and human articular chondrocytes (HACs) were treated with cytokines (IL-1beta and TNFalpha) and the expression of MMP-1 and -13 was analyzed. The effects of MAP kinase inhibitors on cytokine-induced expression of MMP-1 and -13 were evaluated using ELISA and Western blot analyses. The possible involvement of the Runx2 pathway in mediating p38 effects on MMP-13 expression was analyzed using promoter-reporter assays, ELISA and immunoprecipitation analyses.

RESULTS

IL-1beta and TNFalpha strongly induced the expression of MMP-1 and -13 in SW1353 cells and HACs, whereas only TNFalpha was found to induce the expression of these two MMPs in JJ012 cells. Cytokine treatment did not result in a significant increase in the activity of MMPs because of the excess production of endogenous tissue inhibitors of metalloproteases (TIMPs). Treatment with p38 kinase inhibitors (SB203580 and SB242235) strongly inhibited cytokine-induced MMP-13 expression in a dose-dependent fashion while having a somewhat weaker inhibitory effect on MMP-1 expression. In contrast, inhibitors of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) pathways did not inhibit the expression of either MMP. Overexpression of Runx2 robustly stimulated the transcriptional activation of MMP-13 but had no effect on MMP-1 expression. Furthermore, IL-1beta induced the phosphorylation of Runx2, and this effect was blocked by a p38 kinase inhibitor. Our data suggest that Runx2 is likely to be a key downstream mediator of p38 effects in the differential regulation of IL-1beta induced MMP-13 expression.

CONCLUSIONS

These studies demonstrate the differential inhibition of cytokine-induced MMP-1 and -13 expression by p38 kinase inhibitors in human chondrosarcoma cells. Our studies also suggest the involvement of Runx2, at least in part, in mediating the effects of p38 on MMP-13 expression.

Balance between polyoma enhancing activator 3 and activator protein 1 regulates Helicobacter pylori-stimulated matrix metalloproteinase 1 expression

Helicobacter pylori infection and elevated expression of tissue matrix metalloproteinase 1 (MMP-1) are both associated with gastric cancer. We investigated the regulation of MMP-1 expression during H. pylori infection. Real-time reverse transcription-PCR was used to examine mucosal MMP-1 mRNA levels in 55 patients with gastric cancers and 61 control patients. Increased MMP-1 mRNA levels in the gastric mucosa and epithelial cells were observed in H. pylori infections in which both the cag pathogenicity island (PAI) and outer inflammatory protein A (OipA) were expressed. The combined induction of c-fos, c-jun, and polyoma enhancing activator-3 (pea-3) by H. pylori caused maximal increase in MMP-1 expression. Activation of the MMP-1 promoter by H. pylori involved occupation of the activator protein 1 (AP-1) sites at -72 and -181 and, surprisingly, vacancy of the -88 PEA-3 site. Electrophoretic mobility shift, supershift, and chromatin immunoprecipitation assays showed increased binding of c-Fos and c-Jun to the -72 and -181 AP-1 sites during H. pylori infection. Importantly, during wild-type H. pylori infection, we detected increased PEA-3 binding to the -72AP-1 site and decreased PEA-3 binding to the -88 PEA-3 site. However, during infection with the cag PAI and oipA mutants, PEA-3 binding to the -88 site was detected. MMP-1 and pea-3 activities are increased in gastric cancers. Maximal activation of MMP-1 transcription requires the cag PAI and OipA, which regulate AP-1 and PEA-3 binding. Thus, cag PAI and OipA provide a possible link between bacterial virulence factors and important host factors related to disease pathogenesis.

Prostaglandin E2 stimulates p53 transactivational activity through specific serine 15 phosphorylation in human synovial fibroblasts. Role in suppression of c/EBP/NF-kappaB-mediated MEKK1-induced MMP-1 expression

Cyclooxygenase-2 (COX-2) overexpression has been linked to cell survival, transformation, and hyperproliferation. We examined the regulation of the tumor suppressor gene p53 and p53 target genes by prostaglandin E(2) (PGE(2)) in human synovial fibroblasts (HSF). PGE(2) induced a time-dependent increase in p53 Ser(15) phosphorylation, with no discernible change in overall p53 levels. PGE(2)-dependent Ser(15) phosphorylation was apparently mediated by activated p38 MAP kinase as SB202190, a p38 kinase inhibitor, blocked the response. Overexpression of a MKK3 construct, but not MKK1, stimulated SB202190-sensitive p53 Ser(15) phosphorylation. PGE(2)-stimulated [phospho-Ser(15)]p53 transactivated a p53 response element (GADD45)-luciferase reporter in transiently transfected HSF (SN7); the effect was compromised by overexpression of a dominant-negative mutant (dnm) of p53 or excess p53S15A expression plasmid but mimicked by a constitutively active p53S15E expression construct. PGE(2), wtp53 expression in the presence of PGE(2), and p53S15E suppressed steady-state levels of MEKK1-induced MMP-1 mRNA, effects nullified with co-transfection of p53 dnm or p53S15A. MEKK1-induced MMP-1 promoter-driven luciferase activity was largely dependent on a c/EBPbeta-NF-kappaB-like enhancer site at -2008 to -1972 bp, as judged by deletion and point mutation analyses. PGE(2), overexpression of p53wt with PGE(2), or p53S15E abolished the MEKK1-induced MMP-1 promoter luciferase activity. Gel-shift/super gel-shift analyses identified c/EBPbeta dimers and c/EBPbeta/NF-kappaB p65 heterodimers as binding species at the apparent site of MEKK1-dependent transactivation. PGE(2)-stimulated [phospho-Ser(15)]p53 abrogated the DNA binding of c/EBPbeta dimers and c/EBPbeta/NF-kappaB p65 heterodimers. Our data suggest that COX-2 prostaglandins may be implicated in p53 function and p53 target gene expression.

Intercellular adhesion molecule-1 mediates the inhibitory effects of hyaluronan on interleukin-1beta-induced matrix metalloproteinase production in rheumatoid synovial fibroblasts via down-regulation of NF-kappaB and p38

OBJECTIVE

In rheumatoid arthritis (RA), it is well known that rheumatoid synovial fibroblasts (RSF) produce matrix metalloproteinases (MMPs) when stimulated with proinflammatory cytokines such as interleukin-1beta (IL-1beta), which causes joint destruction. We have previously shown that hyaluronan (HA) inhibits IL-1beta actions in RSF via CD44, the principal HA receptor. However, CD44 mediates HA effects only partially, and intracellular events after the HA binding to its receptors remain unclear. We investigated the role of intercellular adhesion molecule-1 (ICAM-1), another cell surface receptor for HA, and the intracellular signalling pathways in the actions of HA.

METHODS

RSF were isolated from rheumatoid synovial tissues by enzymatic digestion and cultured in monolayers. The confluent cells were incubated for 48 h with IL-1beta, IL-1beta in the presence of HA, or IL-1beta in the presence of HA with pretreatment with anti-ICAM-1 antibody. Secretion of MMP-1 and MMP-3 was analysed by immunoblotting and immunofluorescence cytochemistry. Immunofluorescence cytochemistry was also performed to evaluate binding of HA to ICAM-1. The phosphorylation of nuclear factor (NF)-kappaB and mitogen-activated protein kinases (MAPKs) was analysed by immunoblotting.

RESULTS

Production of MMP-1 and MMP-3 by RSF was stimulated by IL-1beta. HA at > or =2 mg/ml significantly inhibited MMP production induced by IL-1beta in a dose-dependent manner. Moreover, pretreatment with anti-ICAM-1 antibody at 50 mug/ml significantly blocked the effects of HA on the actions of IL-1beta on RSF, as shown by immunoblotting and immunofluorescence cytochemistry. Another immunofluorescence cytochemistry study demonstrated that HA bound RSF via ICAM-1. Inhibition studies revealed the requirement of NF-kappaB, p38 and c-jun NH2-terminal kinase (JNK) for IL-1beta-induced MMP production. IL-1beta activated all three pathways, whereas HA down-regulated their phosphorylation. Pretreatment with anti-ICAM-1 antibody reversed the inhibitory effects of HA on the activation of NF-kappaB and p38 without affecting JNK.

CONCLUSION

HA suppresses IL-1beta-enhanced MMP-1 and MMP-3 synthesis in RSF via ICAM-1 through down-regulation of NF-kappaB and p38. Intra-articular injection of HA of high molecular weight may work through such a mechanism in RA joints.

Epidermal growth factor affects the synthesis and degradation of type I collagen in cultured human dermal fibroblasts

EGF and type I collagen are known to play important roles in wound healing. In the present study, we demonstrated that EGF down-regulates the expression of type I procollagen protein as well as alpha2(I) collagen mRNA in cultured human dermal fibroblasts. EGF induced the degradation of type I procollagen protein in conditioned medium through the up-regulation of MMP-1 expression. EGF down-regulated alpha2(I) mRNA expression partially at the post-transcriptional level by reducing the mRNA stability. In contrast, EGF up-regulated MMP-1 mRNA expression mostly at the transcriptional level, in that it had a stimulatory effect on MMP-1 promoter activity, but no effect on MMP-1 mRNA stability. The MEK/ERK signaling pathway was shown to be involved in EGF-mediated type I collagen and MMP-1 expression.

Interleukin-1 beta induction of matrix metalloproteinase-1 transcription in chondrocytes requires ERK-dependent activation of CCAAT enhancer-binding protein-beta

Interleukin-1 beta (IL-1beta) is a central mediator of inflammation and connective tissue destruction in rheumatoid arthritis. IL-1beta activates articular chondrocytes to produce matrix metalloproteinase-1 (MMP-1), an enzyme capable of dismantling the collagen scaffold of articular cartilage. To define the transcription factors and signaling intermediates that activate MMP-1 transcription in chondrocytes, we performed transient transfection of MMP-1 promoter constructs followed by reporter assays. These studies identified an IL-1beta-responsive region of the human MMP-1 promoter that contains a consensus CCAAT enhancer-binding protein (C/EBP) binding site. Deletion of this site reduced overall transcriptional activity of the MMP-1 promoter, as well as decreased fold induction by IL-1beta. IL-1beta stimulation of chondrocytes increased binding of C/EBP-beta to the MMP-1 C/EBP site. Extracellular signal regulated kinase (ERK) pathway-dependent phosphorylation of C/EBP-beta on threonine 235 activates this transcription factor. Here we show that IL-1beta stimulation of chondrocytes induced phosphorylation of C/EBP-beta on threonine 235, and that the ERK pathway inhibitor PD98059 reduced this phosphorylation. We further show that PD98059 reduces IL-1beta-induced MMP-1 mRNA expression in chondrocytes. Moreover, inhibition of the ERK pathway by expression of dominant-negative forms of ERK1 and ERK2 impaired the ability of IL-1beta to transactivate the MMP-1 promoter. Our findings demonstrate a novel role for C/EBP-beta in IL-1beta-induced connective tissue disease and define a new nuclear target for the ERK pathway in MMP-1 gene activation.

Differential expression of matrix metalloproteinase-1 in vitro corresponds to tissue morphogenesis and quality assurance of cultured skin substitutes

OBJECTIVE

To determine if matrix metalloproteinase-1 (MMP-1) was involved in the premature degradation of the dermal component in cultured skin substitutes (CSS) prepared with cells from burn patients.

METHODS AND RESULTS

CSS 645 and 647 were prepared from clinical human fibroblasts (HF) and keratinocytes (HK) that demonstrated premature degradation of collagen-glycosaminoglycan sponges in vitro. The control CSS were prepared from clinical HF and HK, CSS 648, and a pre-clinical cell strain, CSS 644 that did not degrade the sponges. Surface electrical capacitance measures surface hydration and was significantly higher for CSS 647 from days 9 through 14. MTT (3-[4,5-dimethylthiazol-2-yl]- diphenyltetrazolium bromide) conversion, an indicator of cellular viability was significantly lower for the 6-mm punch biopsies from CSS 645 and 647 at day 15 as compared to control CSS. MMP-1 protein levels measured by ELISA were significantly higher in medium from HF 645 and 647 than controls on the day of CSS inoculation. At day 14 of incubation, the mean MMP-1 concentration was significantly elevated in the medium from CSS 645 and 647 versus the controls, CSS 644 and 648. Western blots, and casein zymography demonstrated the presence of the latent and active forms of MMP-1 in the HF and CSS media, respectively.

CONCLUSION

MMP-1 was significantly higher in the media from two of the four HF strains and CSS after a 24 h incubation period. Elevated MMP-1 coincided with premature degradation of the dermal substitute in vitro, and reduced numbers of CSS that met quality assurance standards for clinical transplantation.

Role of macrophage migration inhibitory factor (MIF) in the skin

Macrophage migration inhibitory factor (MIF) functions as a pleiotropic protein, participating in both inflammation and immune responses. MIF was originally discovered as a lymphokine involved in delayed type hypersensitivity and various macrophage functions, including phagocytosis, and tumor surveillance. Recently, MIF has been re-evaluated as a pro-inflammatory cytokine and identified as a pituitary-derived hormone, potentiating endotoxemia. MIF is ubiquitously expressed in various tissues, including the skin. Clinical evidence of increased MIF expression in inflammatory diseases supports this potential role of MIF in inflammation. In addition to its role in inflammation, MIF has been shown to exhibit growth-promoting activity, with anti-MIF antibodies effectively suppressing tumor growth and tumor-associated angiogenesis. This review presents the latest findings on the roles of MIF in the skin with regard to inflammation, the immune response, skin disease, tumorigenesis and cutaneous wound healing, and discusses its potential functions in various pathophysiological states.

Matrix metalloproteinases in cerebrovascular diseases

Matrix metalloproteinases are important factors for tissue remodelling and are activated during several physiological and pathological conditions, including cerebrovascular diseases. We give an overview of the structure, production and physiological effects of these widely distributed proteases and describe the genetic background and regulation pathways. In particular, we discuss the role of matrix metalloproteinases in vascular remodelling concerning ischaemic stroke, brain haemorrhage, vascular dementia, carotid artery plaques and cerebral aneurysms.