Emmprin in epithelioid sarcoma: Expression in tumor cell membrane and stimulation of MMP-2 production in tumor-associated fibroblasts

Roles of Microvesicles in Tumor Progression and Clinical Applications

Microvesicles are extracellular vesicles with diameter ranging from 100 to 1000 nm that are secreted by tumor cells or other cells in the tumor microenvironment. A growing number of studies demonstrate that tumor-derived microvesicles are involved in tumor initiation and progression, as well as drug resistance. In addition, tumor-derived microvesicles carry a variety of immunogenic molecules and inhibit tumor response to immunotherapy; therefore, they can be exploited for use in tumor vaccines. Moreover, because of their high stability, tumor-derived microvesicles extracted from body fluids can be used as biomarkers for cancer diagnosis or assessment of prognosis. Tumor-derived microvesicles can also be deployed to reverse drug resistance of tumor regenerative cells, or to deliver chemotherapeutic drugs and oncolytic adenovirus for the treatment of cancer patients. This review summarizes the general characteristics of tumor-derived microvesicles, focusing on their biological characteristics, their involvement in tumor progression, and their clinical applications.

SDF-1/CXCR4 induces cell invasion through CD147 in squamous cell carcinoma of the hypopharynx

Hypopharyngeal squamous cell carcinoma (SCC) has a poor prognosis due to local invasion and metastasis. The chemokine receptor CXC chemokine receptor type 4 (CXCR4) and its ligand, stromal cell-derived factor 1 (SDF-1), play roles in tumor progression through unclear mechanisms. For the present study, we used a hypopharyngeal SCC cell line, FaDu, expressing CXCR4. We found that SDF-1 promotes migration and invasion of the FaDu cells. In addition, AMD3100, a specific antagonist of CXCR4, inhibited the binding of SDF-1 to CXCR4, resulting in a significant decrease in the FaDu cell migration induced by SDF-1. Stimulation of CXCR4 with SDF-1 induced an increase in the expression of CD147, a cell membrane protein; and this CD147 upregulation was abrogated by AMD3100. CD147 function-blocking antibodies also abolished the SDF-1-induced FaDu invasiveness. Our results suggested that SDF-1/CXCR4 mediate hypopharyngeal SCC cell migration and that CD147 is involved in the SDF-1/CXCR4-related tumor progression.

Highly expressed tumoral emmprin and stromal CD73 predict a poor prognosis for external auditory canal carcinoma

Squamous cell carcinoma of the external auditory canal (SCC-EAC) is rare and has a poor prognosis. The SCC-EAC cases with high-grade tumor budding (TB) or poorly differentiated clusters (PDCs) are associated with shorter survival than those with low-grade TB or PDCs. Extracellular matrix metalloproteinase inducer (emmprin) is a protein expressed in tumor cells that stimulates the production of MMP-2 by stromal fibroblasts to facilitate tumor invasion. Recently, we reported that emmprin forms a complex with CD73 to regulate MMP-2 production from fibroblasts in vitro. Here, we examined the association of emmprin and CD73 expression with TB or PDCs as well as with survival in 34 biopsy specimens of SCC-EAC patients. High tumoral emmprin expression was associated with high-grade TB, whereas high stromal CD73 expression was associated with high-grade PDCs. Furthermore, concurrent elevated expression of tumoral emmprin and stromal CD73 was determined to be an independent poor prognostic factor. In immunoprecipitation analyses, complex formation between emmprin and CD73 was demonstrated in vitro. Production of MMP-2 from fibroblasts was more abundant when cocultured with tumor cells than from fibroblasts cultured alone. Furthermore, MMP-2 production was reduced by the transfection of CD73 siRNA in fibroblasts cocultured with tumor cells. The colocalization of emmprin and CD73 was enhanced in not only the peripheral cells of the tumor cell clusters that interact with fibroblasts but also in the cells of intratumor clusters. Overall, this study provides novel insights into the roles of emmprin, CD73, and MMP-2 in tumor invasiveness.

CD73 complexes with emmprin to regulate MMP-2 production from co-cultured sarcoma cells and fibroblasts

Background

Interaction between cancer cells and fibroblasts mediated by extracellular matrix metalloproteinase inducer (emmprin, CD147) is important in the invasion and proliferation of cancer cells. However, the exact mechanism of emmprin mediated stimulation of matrix metalloprotease-2 (MMP-2) production from fibroblasts has not been elucidated. Our previous studies using an inhibitory peptide against emmprin suggested the presence of a molecule on the cell membrane which forms a complex with emmprin. Here we show that CD73 expressed on fibroblasts interacts with emmprin and is a required factor for MMP-2 production in co-cultures of sarcoma cells with fibroblasts.

Methods

CD73 along with CD99 was identified by mass spectrometry analysis as an emmprin interacting molecule from a co-culture of cancer cells (epithelioid sarcoma cell line FU-EPS-1) and fibroblasts (immortalized fibroblasts cell line ST353i). MMP-2 production was measured by immunoblot and ELISA. The formation of complexes of CD73 with emmprin was confirmed by immunoprecipitation, and their co-localization in tumor cells and fibroblasts was shown by fluorescent immunostaining and proximity ligation assays.

Results

Stimulated MMP-2 production in co-culture of cancer cells and fibroblasts was completely suppressed by siRNA knockdown of CD73, but not by CD99 knockdown. MMP-2 production was not suppressed by CD73-specific enzyme inhibitor (APCP). However, MMP-2 production was decreased by CD73 neutralizing antibodies, suggesting that CD73-mediated suppression of MMP-2 production is non-enzymatic. In human epithelioid sarcoma tissues, emmprin was immunohistochemically detected to be mainly expressed in tumor cells, and CD73 was expressed in fibroblasts and tumor cells: emmprin and CD73 were co-localized predominantly on tumor cells.

Conclusion

This study provides a novel insight into the role of CD73 in emmprin-mediated regulation of MMP-2 production.

Efficacy Evaluation of Combination Treatment Using Gemcitabine and Radioimmunotherapy with 90Y-Labeled Fully Human Anti-CD147 Monoclonal Antibody 059-053 in a BxPC-3 Xenograft Mouse Model of Refractory Pancreatic Cancer

The poor prognosis of pancreatic cancer requires the development of more effective therapy. CD147 expresses in pancreatic cancer with high incidence and has a crucial role in invasion and metastasis. We developed a fully human monoclonal antibody (059-053) with high affinity for CD147. Here we evaluated the efficacy of combined treatment using radioimmunotherapy (RIT) with ⁹⁰Y-labeled 059-053 and gemcitabine in a BxPC-3 xenograft mouse model. Expression of CD147 and matrix metalloproteinase-2 (MMP2) in BxPC-3 tumors was evaluated. In vitro and in vivo properties of 059-053 were evaluated using ¹¹¹In-labeled 059-053 and a pancreatic cancer model BxPC-3. Tumor volume and body weight were periodically measured in mice receiving gemcitabine, RIT, and both RIT and gemcitabine (one cycle and two cycles). High expression of CD147 and MMP2 was observed in BxPC-3 tumors and suppressed by 059-053 injection. Radiolabeled 059-053 bound specifically to BxPC-3 cells and accumulated highly in BxPC-3 tumors but low in major organs. Combined treatment using RIT with gemcitabine (one cycle) significantly suppressed tumor growth and prolonged survival with tolerable toxicity. The two-cycle regimen had the highest anti-tumor effect, but was not tolerable. Combined treatment with ⁹⁰Y-labeled 059-053 and gemcitabine is a promising therapeutic option for pancreatic cancer.

CD147 expression correlates with lymph node metastasis in T1-T2 squamous cell carcinoma of the tongue

Cervical lymph node metastasis causes a poor prognosis in cases of stage T1-T2 squamous cell carcinoma (SCC) of the tongue. Recent studies have reported that cluster of differentiation (CD)147, also known as extracellular matrix metalloproteinase inducer, contributes to tumor progression. The present study evaluated the role of CD147 in the tumorigenesis of SCC of the tongue in vitro, as well as the association between CD147 expression and cervical lymph node metastasis in clinical samples of SCC of the tongue. Tongue SCC cell lines were used to evaluate in vitro tumorigenesis. In addition, 41 patients with clinical stage T1-T2 tongue SCC were assessed with a histopathological analysis. Univariate and multivariate analysis were performed to investigate the risk of cervical lymph node metastasis associated with histopathological findings. In the in vitro study, cell invasiveness was upregulated by S100 calcium-binding protein A9 (S100A9) stimulation and downregulated following CD147-blocking antibody treatment. The univariate and multivariate analyses identified CD147 expression in the invasive tumor front as an independent risk factor for metastasis. It was concluded that CD147 induces tongue carcinoma cell invasion through its interaction with S100A9. Thus, an evaluation of the extent of CD147 expression in cancer cell nests at the invasive tumor front may help in predicting cervical lymph node metastasis in patients with clinical N0 T1-T2 tongue SCC.

The prostate metastasis suppressor gene NDRG1 differentially regulates cell motility and invasion

Experimental and clinical evidence suggests that N-myc downregulated gene 1 (NDRG1) functions as a suppressor of prostate cancer metastasis. Elucidating pathways that drive survival and invasiveness of NDRG1-deficient prostate cancer cells can help in designing therapeutics to target metastatic prostate cancer cells. However, the molecular mechanisms that lead NDRG1-deficient prostate cancer cells to increased invasiveness remain largely unknown. In this study, we demonstrate that NDRG1-deficient prostate tumors have decreased integrin expression and reduced cell adhesion and motility. Our data indicate that loss of NDRG1 differentially affects Rho GTPases. Specifically, there is a downregulation of active RhoA and Rac1 GTPases with a concomitant upregulation of active Cdc42 in NDRG1-deficient cells. Live cell imaging using a fluorescent sensor that binds to polymerized actin revealed that NDRG1-deficient cells have restricted actin dynamics, thereby affecting cell migration. These cellular and molecular characteristics are in sharp contrast to what is expected after loss of a metastasis suppressor. We further demonstrate that NDRG1-deficient cells have increased resistance to anoikis and increased invasiveness which is independent of its elevated Cdc42 activity. Furthermore, NDRG1 regulates expression and glycosylation of EMMPRIN, a master regulator of matrix metalloproteases. NDRG1 deficiency leads to an increase in EMMPRIN expression with a concomitant increase in matrix metalloproteases and thus invadopodial activity. Using a three-dimensional invasion assay and an in vivo metastasis assay for human prostate xenografts, we demonstrate that NDRG1-deficient prostate cancer cells exhibit a collective invasion phenotype and are highly invasive. Thus, our findings provide novel insights suggesting that loss of NDRG1 leads to a decrease in actin-mediated cellular motility but an increase in cellular invasion, resulting in increased tumor dissemination which positively impacts metastatic outcome.

Emmprin, released as a microvesicle in epithelioid sarcoma, interacts with fibroblasts

Emmprin (extracellular matrix metalloproteinase inducer, CD147) is a glycosylated transmembrane protein, consisting of two immunoglobulin domains, that stimulates the production of matrix metalloproteinases (MMPs) by tumor-associated fibroblasts. These effects play important roles in tumor invasion and metastasis. However, the precise mechanisms by which emmprin acts on fibroblasts have not been fully elucidated, especially in sarcoma cells. Previously, we demonstrated that emmprin, expressed in conditioned medium collected from the epithelioid sarcoma cell line (FU-EPS-1), stimulates MMP-2 production via interactions with fibroblasts. In this study, we used microvesicles derived from sarcoma cells, and determined whether emmprin exists in the microvesicles, which enhance the production of MMP-2 via fibroblasts. Microvesicles released from FU-EPS-1 cells were shown to contain full-length emmprin, identified as a 45-kDa protein characterized by polylactosamine glycosylation. Microvesicles collected from FU-EPS-1 cells transfected with emmprin-specific siRNA or transduced with shRNA displayed significantly reduced MMP-2 production by fibroblasts compared with those from control-transfected cells. Our findings show that emmprin is released through microvesicle shedding in sarcoma cells, and emmprin in microvesicles regulates MMP-2 production by influencing the activity of fibroblasts located at sites distant from the tumor cells.

Soluble extracellular matrix metalloproteinase inducer (EMMPRIN, EMN) regulates cancer-related cellular functions by homotypic interactions with surface CD147

EMMPRIN (extracellular matrix metalloproteinase inducer) is a widely expressed glycoprotein and a member of the immunoglobulin superfamily which exists in both a membrane-spanning and a soluble form. Homotypic interactions of EMMPRIN underlie its multiple roles in normal development and pathological situations such as viral infections, Alzheimer's disease and cancer. This study employed a recombinant soluble, fully glycosylated EMMPRIN domain (rhsEMN) as a tool to characterize the structural basis of EMMPRIN-EMMPRIN receptor (EMNR) contacts and their functional effects on MCF-7 breast carcinoma cells. rhsEMN did not form dimers in solution but bound to surface EMMPRIN (EMN) on MCF-7 cells with high affinity and was readily internalized. The interaction interface for the homotypic contact was localized to the N-terminal Ig domain. rhsEMN exerted a stimulatory effect on proliferation of MCF-7 cells whereas it reduced cell migration in a dose-dependent manner. These effects were accompanied by an upregulation of endogenous EMMPRIN as well as of matrix metalloproteinase-14 (MMP-14), a membrane-bound protease involved in the extracellular release of soluble EMMPRIN, indicating a regulatory feedback mechanism. The proliferation-promoting activity of rhsEMN was mimicked by a novel functional antibody directed to EMMPRIN, underscoring that crosslinking of cell surface EMMPRIN (EMNR) is crucial for eliciting intracellular signalling. Addressing malignancy-related signal transduction in HEK-293 cells, we could show that rhsEMN triggers the oncogenic Wnt pathway.

Role of matrix metalloproteinase (MMP) 2 and MMP-9 in soft tissue sarcoma

Background

We investigated the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in malignant fibrous histiocytoma (MFH), and determined whether these could be useful as prognostic factors.

Methods

Among patients treated from 1993 to 2007, 30 cases of MFH were evaluated. Immunohistochemical staining was performed for MMP-2, MMP-9, TIMP-1, and TIMP-2 using paraffin wax-embedded blocks of MFH tissues. Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot and zymography were performed using fresh tissues obtained from 17 of the 30 cases. The levels of MMP and TIMP expression were compared between the MFH and normal control groups, and between non-metastatic and metastatic MFH groups.

Results

Expression levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were higher in the MFH group than the control group by RT-PCR, Western blotting, and zymography. Immunohistochemical staining revealed that MMP-2 and MMP-9 protein expression was higher in the metastatic than in the non-metastatic group. The expression levels of MMP-2 and TIMP-1 were significantly higher in the metastatic than in the non-metastatic group (p < 0.05) by RT-PCR. By Western blot analysis, the expression levels of MMP-2, TIMP-1, and TIMP-2 were higher in the metastatic group (p < 0.05), but MMP-9 showed only a slight increase in the metastatic group compared with the non-metastatic group (p > 0.05). Finally, gelatin zymography analysis showed that the expression levels of the pro- and active forms of MMP-2 were significantly higher in the metastatic group (p < 0.05), but the expression of the pro- and active forms of MMP-9 showed a slight decrease in the metastatic group (p > 0.05).

Conclusions

These results suggest that MMP-2, MMP-9, TIMP-1, and TIMP-2 may have important roles in the development and progression of MFH, and that the degree of expression of these metalloproteinases and their inhibitors, especially MMP-2, could be useful as prognostic factors related to metastasis in MFH.

Inflammatory stress and sarcomagenesis: a vicious interplay

Chronic inflammation represents one of the hallmarks of cancer, but its role in sarcomagenesis has long been overlooked. Sarcomas are a rare and heterogeneous group of tumors of mesenchymal origin accounting for less than 1 % of cancers in adults but 21 % of cancers in the pediatric population. Sarcomas are associated with bad prognosis, and their management requires a multidisciplinary team approach. Several lines of evidence indicate that inflammation has been implicated in sarcomagenesis leading to the activation of the key transcription factors HIF-1, NF- κB, and STAT-3 involved in a complex inflammatory network. In the past years, an increasing number of new targets have been identified in the treatment of sarcomas leading to the development of new drugs that aim to interrupt the vicious connection between inflammation and sarcomagenesis. This article makes a brief overview of preclinical and clinical evidence of the molecular pathways involved in the inflammatory stress response in sarcomagenesis and the most targeted therapies.

The role of inflammation in sarcoma

Sarcomas encompass a heterogenous group of tumors with diverse pathologically and clinically overlapping features. It is a rarely curable disease, and their management requires a multidisciplinary team approach. Chronic inflammation has emerged as one of the hallmarks of tumors including sarcomas. Classical inflammation-associated sarcomas comprise the inflammatory malignant fibrous histiocytoma and Kaposi sarcoma. The identification of specific chromosomal translocations and important intracellular signaling pathways such as Ras/Raf/MAPK, insulin-like growth factor, PI3K/AKT/mTOR, sonic hedgehog and Notch together with the increasing knowledge of angiogenesis has led to development of targeted therapies that aim to interrupt these pathways. Innovative agents like oncolytic viruses opened the way to design new therapeutic options with encouraging findings. Preclinical evidence also highlights the therapeutic potential of anti-inflammatory nutraceuticals as they can inhibit multiple pathways while being less toxic. This chapter gives an overview of actual therapeutic standards, newest evidence-based studies and exciting options for targeted therapies in sarcomas.

Extracellular matrix remodeling by bone marrow fibroblast-like cells correlates with disease progression in multiple myeloma

The pathogenesis of multiple myeloma (MM) is regarded as a multistep process, in which an asymptomatic stage of monoclonal gammopathy of undetermined significance (MGUS) precedes virtually all cases of MM. Molecular events characteristic for the transition from MGUS to MM are still poorly defined. We hypothesized that fibroblast-like cells in the tumor microenvironment are critically involved in the pathogenesis of MM. Therefore, we performed a comparative proteome profiling study, analyzing primary human fibroblast-like cells isolated from the bone marrow of MM, of MGUS, as well as of non-neoplastic control patients. Thereby, a group of extracellular matrix (ECM) proteins, ECM receptors, and ECM-modulating enzymes turned out to be progressively up-regulated in MGUS and MM. These proteins include laminin α4, lysyl-hydroxylase 2, prolyl 4-hydroxylase 1, nidogen-2, integrin α5β5, c-type mannose receptor 2, PAI-1, basigin, and MMP-2, in addition to PDGF-receptor β and the growth factor periostin, which are likewise involved in ECM activities. Our results indicate that ECM remodeling by fibroblast-like cells may take place already at the level of MGUS and may become even more pronounced in MM. The identified proteins which indicate the stepwise progression from MGUS to MM may offer new tools for therapeutic strategies.

The role of extracellular matrix metalloproteinase inducer (EMMPRIN) in the regulation of bovine endometrial cell functions

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a cell surface glycoprotein that stimulates the production of several matrix metalloproteinases (MMPs) for tissue remodeling. Previously, we detected EMMPRIN in the bovine endometrium, and it is mainly expressed in the luminal and glandular epithelium whereas MMPs are expressed in the underlying stroma. From this expression pattern, we hypothesized that EMMPRIN may regulate stromal MMPs in endometrial cell functions. To test this hypothesis, a coculture of epithelial and stromal cells was performed using a transwell system. In the coculture, epithelial cells were cultured on the insert membrane and stromal cell on the surface of well plates. Expression of stromal MMP-2 and MMP-14 was significantly higher in coculture with epithelial cell. Further, with the addition of anti-EMMPRIN antibody into the epithelial cell compartment, the expression of stromal EMMPRIN and MMP-2 and MMP-14 was decreased. To identify the active site of EMMPRIN for the augmentation of MMPs, EMMPRIN synthetic peptides that correspond to the extracellular loop domain-I (EM1, EM2, EM3, and EM4) were added into the epithelial cell compartment, and only EM2 at a higher dose interfered with EMMPRIN-mediated expression of MMP-14. Next, we examined the effects of progesterone and/or estrogen on the expression of EMMPRIN, MMP-2, and MMP-14. Progesterone (300 nM) significantly stimulated the expression of EMMPRIN but had no effects on any of the MMPs. These results suggest that EMMPRIN derived from epithelial cells regulates MMPs in the endometrium under progesterone-rich conditions and may thereby modulate bovine endometrial cell functions during gestation.

Expression patterns of emmprin and monocarboxylate transporter-1 in ovarian epithelial tumors

Emmprin is a transmembrane glycoprotein known as a matrix metalloproteinase inducer and is highly up-regulated in malignant cancer cells. The monocarboxylate transporters (MCTs) are responsible for H(+)-linked transport of monocarboxylates across the cell membrane. It was recently demonstrated that proper plasma membrane localization and activity of MCTs require the presence of emmprin as a chaperone and that MCT-1 also acts as chaperone for emmprin. The objectives of this study were to clarify emmprin and MCT-1 expression patterns in ovarian epithelial tumors and to elucidate the clinicopathological significance of co-localization of the two molecules. Immunohistochemical analysis of 205 epithelial tumors indicated that emmprin is always localized in cell membranes but its distribution differs according to tumor type: in lateral membranes in 89 % of adenomas, in lateral and basal membranes in 76 % of borderline tumors, and in membranes surrounding the entire cell in 98 % of carcinomas. Most carcinomas in situ also showed a lateral and basal expression pattern. In only 21 % of the carcinomas, the cells expressing membranous MCT-1 showed co-localized emmprin expression. Poor co-localization of the two molecules was more frequently found in serous carcinomas. However, the overall survival was not significantly different for the good and poor co-localization carcinoma groups. These findings indicate that the emmprin expression pattern might discriminate between invasive carcinomas and borderline tumors including carcinoma in situ. Moreover, there may be an as yet unidentified regulatory mechanism(s), for localization of MCT-1 and emmprin in cell membranes in vivo.

Synthetic emmprin peptides with chitobiose substitution stimulate MMP-2 production by fibroblasts

Background

Emmprin, a glycoprotein containing two Ig domains, is enriched on tumor cell surfaces and stimulates matrix metalloproteinase (MMP) production by adjacent stromal cells. Its first Ig domain (ECI) contains the biologically active site. The dependence of emmprin activity on N-glycosylation is controversial. We investigated whether synthetic ECI with the shortest sugar is functionally active.

Methods

The whole ECI peptides carrying sugar chains, a chitobiose unit or N-linked core pentasaccharide, were synthesized by the thioester method and added to fibroblasts to examine whether they stimulate MMP-2 production.

Results

ECI carrying a chitobiose unit, ECI-(GlcNAc) ₂, but not ECI without a chitobiose unit or the chitobiose unit alone, dose-dependently stimulated MMP-2 production by fibroblasts. ECI with longer chitobiose units, ECI-[(Man)₃(GlcNAc)₂], also stimulated MMP-2 production, but the extent of its stimulation was lower than that of ECI-(GlcNAc)₂.

Conclusions

Our results indicate that ECI can mimic emmprin activity when substituted with chitobiose, the disaccharide with which N-glycosylation starts.

High levels of extracellular matrix metalloproteinase inducer are expressed in lymphangioleiomyomatosis

Pulmonary lymphangioleiomyomatosis is pathologically characterized by the proliferation of abnormal smooth muscle-like cells (lymphangioleiomyomatosis cells) that synthesize excess matrix metalloproteinases. Extracellular matrix metalloproteinase inducer is minimally expressed in the healthy lung, but is up-regulated in various lung injuries that are apparently associated with matrix metalloproteinases. We therefore immunohistochemically stained extracellular matrix metalloproteinase inducer in lymphangioleiomyomatosis cells and measured extracellular matrix metalloproteinase inducer in bronchoalveolar lavage fluid using an enzyme-linked immunosorbent assay. We also quantified extracellular matrix metalloproteinase inducer messenger RNA expression in the lung using quantitative reverse transcriptase-polymerase chain reaction. Intense staining for extracellular matrix metalloproteinase inducer in lymphangioleiomyomatosis cells indicated high immunoreactivity. Dual immunofluorescence studies revealed diffuse colocalization between extracellular matrix metalloproteinase inducer and alpha smooth muscle actin, matrix metalloproteinase-2, or matrix metalloproteinase-9. Although levels of extracellular matrix metalloproteinase inducer messenger RNA did not differ in whole lung homogenates from patients with lymphangioleiomyomatosis and healthy controls (1.7 +/- 0.1 versus 1.5 +/- 0.2 SE, not significant; both n = 4), lymphangioleiomyomatosis nodules retrieved by laser capture microdissection expressed 5.1 (+/-1.0 SE)-fold higher levels of extracellular matrix metalloproteinase inducer messenger RNA than lung homogenates (P = .0077, n = 4). Levels of extracellular matrix metalloproteinase inducer were significantly elevated in bronchoalveolar lavage fluid from lymphangioleiomyomatosis patients compared with controls (82.7 +/- 19.5 versus 38.6 +/- 9.0 SE pg/mL, P = .0497; n = 8 and 9, respectively). Increased levels of extracellular matrix metalloproteinase inducer colocalized with increased matrix metalloproteinases in lymphangioleiomyomatosis cells indicate that it potentially functions in pulmonary lymphangioleiomyomatosis.

CD147/basigin promotes progression of malignant melanoma and other cancers

CD147/basigin, a transmembrane protein belonging to the immunoglobulin super family, was originally cloned as a carrier of Lewis X carbohydrate antigen. CD147 is strongly related to cancer progression; it is highly expressed by various cancer cells including malignant melanoma (MM) cells and it plays important roles in tumor invasiveness, metastasis, cellular proliferation, and in vascular endothelial growth factor (VEGF) production, tumor cell glycolysis, and multi-drug resistance (MDR). CD147 on cancer cells induces matrix metalloproteinase expression by neighboring fibroblasts, leading to tumor cell invasion. In a nude mouse model of pulmonary metastasis from MM, the metastatic potential of CD147-expressing MM cells injected into the tail vein is abolished by CD147 silencing. CD147 enhances cellular proliferation and VEGF production by MM cells; it promotes tumor cell glycolysis by facilitating lactate transport in combination with monocarboxylate transporters, resulting in tumor progression. CD147 is responsible for the MDR phenotype via P-glycoprotein expression. These findings strongly suggest CD147 as a possible therapeutic target for overcoming metastasis and MDR, major obstacles to the effective treatment of malignant cancers.

Soluble EMMPRIN (extra-cellular matrix metalloproteinase inducer) stimulates the migration of HEp-2 human laryngeal carcinoma cells, accompanied by increased MMP-2 production in fibroblasts

The basement membrane functions as a barrier against the invasion of cancer cells. It is therefore important to investigate the mechanism of basement membrane degradation by matrix metalloproteinases (MMPs). Previously, cancer cells were long considered to be the major source of MMPs; however, current evidence indicates that most MMPs in cancer tissue are produced by stromal rather than cancer cells. A glycoprotein highly expressed on the cancer-cell membrane, EMMPRIN (extra-cellular matrix metalloproteinase inducer), exhibits the potential role of the MMP inductor in stromal cells. Depending on the cell type, EMMPRIN can stimulate the production of MMP-1, MMP-2, and MMP-3. We here report that soluble full-length EMMPRIN is liberated from HEp-2 human laryngeal epidermoid carcinoma cells, probably via microvesicle shedding. Soluble EMMPRIN stimulates human fibroblasts to produce MMP-2, after which the augmented migration of HEp-2 cells occurs, as observed in an invasion chamber assay with separately cultured fibroblasts. An anti-EMMPRIN function-blocking antibody reduced MMP-2 activity in the conditioned medium and inhibited the migration of HEp-2; obviously, EMMPRIN activity contributes to cancer-cell migration. We postulate that soluble EMMPRIN probably triggers the promotion of cancer invasion in vivo.

Cardiac-restricted overexpression of extracellular matrix metalloproteinase inducer causes myocardial remodeling and dysfunction in aging mice

The matrix metalloproteinases (MMPs) play a pivotal role in adverse left ventricular (LV) myocardial remodeling. The transmembrane protein extracellular MMP inducer (EMMPRIN) causes increased MMP expression in vitro, and elevated levels occur in patients with LV failure. However, the direct consequences of a prolonged increase in the myocardial expression of EMMPRIN in vivo remained unexplored. Cardiac-restricted EMMPRIN expression (EMMPRINexp) was constructed in mice using the full-length human EMMPRIN gene ligated to the myosin heavy chain promoter, which yielded approximately a twofold increase in EMMPRIN compared with that of the age/strain-matched wild-type (WT) mice; EMMPRINexp (n=27) and WT (n=33) mice were examined at 3.2+/-0.1 or at 13.3+/-0.5 mo of age (n=43 and 26, respectively). LV end-diastolic volume (EDV) was similar in young EMMPRINexp and WT mice (54+/-2 vs. 57+/-3 microl), but LV ejection fraction (EF) was reduced (51+/-1 vs. 57+/-1%; P<0.05). In old EMMPRINexp mice, LV EDV was increased compared with WT mice values (76+/-3 vs. 58+/-3 microl; P<0.05) and LV EF was significantly reduced (45+/-1 vs. 57+/-2%; P<0.05). In EMMPRINexp old mice, myocardial MMP-2 and membrane type-1 MMP levels were increased by >50% from WT values (P<0.05) and were accompanied by a twofold higher collagen content (P<0.05). Persistent myocardial EMMPRINexp in aging mice caused increased levels of both soluble and membrane type MMPs, fibrosis, and was associated with adverse LV remodeling. These findings suggest that EMMPRIN is an upstream signaling pathway that can play a mechanistic role in adverse remodeling within the myocardium.