Emmprin (CD147), a cell surface regulator of matrix metalloproteinase production and function

Overexpression of CD147 in ovarian cancer is initiated by the hypoxic microenvironment

Ovarian cancer is a lethal malignant tumour characterised by activated invasion, distant metastasis, anti-cancer drug resistance, angiogenesis and metabolism. CD147, an extracellular matrix metalloproteinase inducer, is overexpressed in most ovarian tumours and plays an important role in the progression of ovarian cancer and other malignant tumours. However, the factor(s) initiating this overexpression is unknown. Because of rapid reproduction and their hypoxic microenvironment, malignant tumours use glycolysis for energy, and lactic acid produced is harmful to the cells. For survival, excessive lactate needs to be transported by monocarboxylate transporters (MCTs). Functioning of MCT1 and MCT4 require the ancillary of CD147. The gene for CD147 possesses two hypoxia-inducible factors binding sites in its 3'-flank. It is logical to postulate that the hypoxic microenvironment is a major initiator of the overexpression of CD147, thus conferring on ovarian cancers their malignant properties. A model that can represent spontaneous ovarian cancer is necessary to verify this hypothesis.

RNA interference targeting CD147 inhibits the invasion of human cervical squamous carcinoma cells by downregulating MMP-9

Cervical squamous carcinoma is a highly invasive tumour that has a great capacity to metastasise. Extracellular matrix metalloproteinase inducer (EMMPRIN or CD147), a member of the immunoglobulin superfamily, is a widely distributed cell surface glycoprotein. It is highly expressed on malignant tumour cell surfaces, including human cervical squamous carcinoma. It also plays a critical role in the invasive and metastatic activity of malignant cells by stimulating the expression of matrix metalloproteinases (MMPs). The anti-invasive effect of small interfering RNA (siRNA) against CD147 on human cervical squamous carcinoma cells and its possible pathways has been investigated. The downregulation of CD147 by transfection with siRNA resulted in MMP-9 expression and decreased activity in the cervical squamous carcinoma cell line SiHa. In vitro analysis showed that the invasive capacity of SiHa cells decreased. Thus CD147 inhibition and subsequent MMP-9 deletion may have anti-tumour effects by inhibiting the invasiveness of human cervical squamous carcinoma cells.

4F2hc-silencing impairs tumorigenicity of HeLa cells via modulation of galectin-3 and β-catenin signaling, and MMP-2 expression

4F2hc is a type-II glycoprotein whose covalent-bound association with one of several described light chains yields a heterodimer mainly involved in large neutral amino acid transport. Likewise, it is well known that the heavy chain interacts with β-integrins mediating integrin-dependent events such as survival, proliferation, migration and even transformation. 4F2hc is a ubiquitous protein whose overexpression has been related to tumor development and progression. Stable silencing of 4F2hc in HeLa cells using an artificial miRNA impairs in vivo tumorigenicity and leads to an ineffective proliferation response to mitogens. 4F2hc colocalizes with β1-integrins and CD147, but this interaction does not occur in lipid rafts in HeLa cells. Moreover, silenced cells present defects in integrin- (FAK, Akt and ERK1/2) and hypoxia-dependent signaling, and reduced expression/activity of MMP-2. These alterations seem to be dependent on the inappropriate formation of CD147/4F2hc/β1-integrin heterocomplexes on the cell surface, arising when CD147 cannot interact with 4F2hc. Although extracellular galectin-3 accumulates due to the decrease in MMP-2 activity, galectin-3 signaling events are blocked due to an impaired interaction with 4F2hc, inducing an increased degradation of β-catenin. Furthermore, cell motility is compromised after protein silencing, suggesting that 4F2hc is related to tumor invasion by facilitating cell motility. Therefore, here we propose a molecular mechanism by which 4F2hc participates in tumor progression, favoring first steps of epithelial-mesenchymal transition by inhibition of β-catenin proteasomal degradation through Akt/GSK-3β signaling and enabling cell motility.

Basigin-2 is the predominant basigin isoform that promotes tumor cell migration and invasion and correlates with poor prognosis in epithelial ovarian cancer

Background

Basigin, which has four isoforms, has been demonstrated to be involved in progression of various human cancers. The aim of this study was to examine the prognostic value of basigin-2 protein expression in epithelial ovarian cancer. Furthermore, the function of basigin-2 in ovarian cancer was further investigated in cell culture models.

Methods

Immunohistochemistry staining was performed to investigate basigin-2 expression in a total of 146 ovarian tissue specimens. Kaplan Meier analysis and Cox proportional hazards model were applied to assess the relationship between basigin-2 and progression-free survival (PFS) and overall survival (OS). Real-time PCR, RT-PCR and western blot were used to explore basigin-2, basigin-3 and basigin-4 expression in ovarian cancer cell lines and tissues. To evaluate possible contributions of basigin-2 to MMP secretion and cell migration and invasion, the overexpression vectors pcDNA3.1-basigin-2 and basigin-2 siRNA were transfected into HO-8910 and HO-8910 PM cells respectively.

Results

High basigin-2 expression was associated with lymph-vascular space involvement, lymph node metastasis and poor prognosis of epithelial ovarian cancer. Multivariate analyses indicated that basigin-2 positivity was an independent prognostic factor for PFS (P = 0.006) and OS (P = 0.019), respectively. Overexpression of basigin-2 increased the secretion of MMP-2/9 and cancer cell migration and invasion of HO-8910 cells, whereas knockdown of basigin-2 reduced active MMP-2/9 production, migration and invasion of HO-8910 PM cells.

Conclusions

The expression of basigin-2 might be an independent prognostic marker and basigin-2 inhibition would be a potential strategy for epithelial ovarian cancer patients, especially in inhibiting and preventing cancer cell invasion and metastasis.

Membrane-associated matrix proteolysis and heart failure

The extracellular matrix (ECM) is a complex entity containing a large portfolio of structural proteins, signaling molecules, and proteases. Changes in the overall integrity and activational state of these ECM constituents can contribute to tissue structure and function, which is certainly true of the myocardium. Changes in the expression patterns and activational states of a family of ECM proteolytic enzymes, the matrix metalloproteinases (MMPs), have been identified in all forms of left ventricle remodeling and can be a contributory factor in the progression to heart failure. However, new clinical and basic research has identified some surprising and unpredicted changes in MMP profiles in left ventricle remodeling processes, such as with pressure or volume overload, as well as with myocardial infarction. From these studies, it has become recognized that proteolytic processing of signaling molecules by certain MMP types, particularly the transmembrane MMPs, actually may facilitate ECM accumulation and modulate fibroblast transdifferentiation; both are critical events in adverse left ventricle remodeling. Based on the ever-increasing substrates and diversity of biological actions of MMPs, it is likely that continued research about the relationship of left ventricle remodeling in this family of proteases will yield new insights into the ECM remodeling process and new therapeutic targets.

CD147, MMP9 expression and clinical significance of basal-like breast cancer

Our objective is to investigate the expression of CD147 and metallo-proteinase 9 (MMP9) in patients with basal-like breast cancer (BLBC) so as to determine whether these two genes may be correlated with prognosis of BLBC. We examined the expression of the CD147 and MMP9 in BLBC by immunohistochemistry. Furthermore, we analyzed the correlation between BLBC and several factors related to tumor progression, along with the prognostic value of BLBC. BLBC was significantly associated with CD147 and MMP9 expression (P = 0.000), and prone to lymph node metastasis and distant metastasis. Patients with BLBC showed shorter disease-free survival (P = 0.005) and overall survival (OS) (P = 0.011). In univariate analysis, CD147, MMP9, lymph node metastasis and clinical stage are independent prognostic factors affecting OS. In multivariate analysis, only clinical stage was identified as an independent prognostic factor. Patients with BLBC have a high expression of CD147 and MMP9; BLBC is correlated with a poor prognosis.

Extracellular matrix metalloproteinase inducer is associated with severity of brain oedema following experimental subarachnoid haemorrhage in rats

OBJECTIVE

Brain oedema is a major cause of clinical deterioration and death following brain trauma; cellular mechanisms involved in its development remain elusive. This study investigated the role of extracellular matrix metalloproteinase inducer (EMMPRIN) in brain oedema.

METHODS

The monofilament puncture model was used to induce subarachnoid haemorrhage. Adult male Sprague-Dawley rats were divided into five groups (n = 20 per group): sham-operated, sacrificed immediately after surgery (sham group); sacrificed 12, 24 or 72 h after subarachnoid haemorrhage induction (SAH-12, SAH-24 and SAH-72 groups, respectively); treated with EMMPRIN inhibitor immediately after subarachnoid haemorrhage, sacrificed at 24 h (SAH-inhibition group). Mean brain water content, and EMMPRIN mRNA and protein levels, were determined.

RESULTS

Compared with the sham group, mean brain water content, EMMPRIN mRNA and protein levels in the SAH-12, SAH-24 and SAH-72 groups increased rapidly and significantly (maximal at 24 h). EMMPRIN inhibition significantly reduced mean brain water content and EMMPRIN mRNA and protein levels in the SAH-inhibition group, compared with the SAH-24 group.

CONCLUSIONS

EMMPRIN upregulation may be important in the formation of brain oedema; inhibition of EMMPRIN activity may provide a potential approach to reduce oedema after subarachnoid haemorrhage.

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.

High expression of CD147 and MMP-9 is correlated with poor prognosis of triple-negative breast cancer (TNBC) patients

The aim of this study was to investigate expression of CD147 and MMP-9 in triple-negative breast cancer (TNBC) so as to determine whether these two proteins may be correlated with poor prognosis of TNBC patients. We examined the expression levels of the CD147 and MMP-9 in 127 patients with TNBC and 30 patients with mammary gland fibroma using immunohistochemical staining before any treatments. Furthermore, we analyzed the correlation between the expression of these two proteins and various clinicopathologic factors including survival status of patients with TNBC. Positive stain of CD147 and MMP-9 was observed in all samples of TNBC. A statistically positive correlation was observed between the expression levels of CD147 and MMP-9 in TNBC tissues. The incidences of high expression were 48.0 % for CD147 and 53.5 % for MMP-9 in 127 TNBC tissues, respectively. High expression of either CD147 or MMP-9 was significantly correlated with clinical feature and shorter progression-free survival (PFS) (P(CD147) = 0.039; P(MMP-9) = 0.017) and overall survival (OS) (P(CD147) = 0.037; P(MMP-9) = 0.023). The expression levels of CD147 and MMP-9 are positively correlated with invasion, metastasis and shorter PFS/OS of TNBC. Patients with high expression of CD147 and MMP-9 had poor prognosis than TNBC patients with low expression.

Modulation of CD147-induced matrix metalloproteinase activity: role of CD147 N-glycosylation

Degradation of the basement membrane by MMPs (matrix metalloproteinases) is one of the most critical steps in tumour progression. CD147 is a tumour-associated antigen that plays a key regulatory role for MMP activities. In the present study, mass spectrum analysis demonstrated that the purified native CD147 from human lung cancer tissue was N-glycosylated and contained a series of high-mannose and complex-type N-linked glycan structures. Moreover, native glycosylated CD147 existed exclusively as oligomers in solution and directly stimulated MMP production more efficiently than non-glycosylated prokaryotic CD147. The glycosylation site mutation results indicated that, among three N-glycan attachment sites, the N152Q mutants were retained in the endoplasmic reticulum and unfolded protein response signalling was activated. This improper intracellular accumulation impaired its MMP-inducing activity. Increased β1,6-branching of N-glycans as a result of overexpression of GnT-V (N-acetylglucosaminyltransferase V) plays an important role in tumour metastasis. In the present study, we identified CD147 as a target protein of GnT-V and found that overexpression of GnT-V resulted in an elevated level of CD147 at the plasma membrane and in cell-conditioned medium, thereby increasing the induction of MMPs. The present study reveals the important role of N-glycosylation of CD147 in its biological function and implied that targeting aberrant β1,6-branching of N-glycans on CD147 would be valuable for the development of novel therapeutic modalities against carcinoma.

HAb18G/CD147 promotes activation of hepatic stellate cells and is a target for antibody therapy of liver fibrosis

BACKGROUND & AIMS

Activated hepatic stellate cells (HSCs) located in the Disse's space play a crucial role in liver fibrosis. HAb18G/CD147, a tumor-related glycoprotein, is highly expressed in hepatocellular carcinoma cells and fibroblasts. Whether HAb18G/CD147 plays an important role in the hepatic fibrogenesis is unknown.

METHODS

Immunohistochemistry for HAb18G/CD147 and α-smooth muscle actin expression in diseased liver tissues was used for correlation analysis. The function of HAb18G/CD147 in fibrogenesis was evaluated with the human HSCs LX-2 cell line and carbon tetrachloride-induced mouse liver fibrosis model. The specific antibody HAb18 targeting HAb18G/CD147 was injected intravenously into the mouse to investigate whether HAb18G/CD147 could be a potential target for liver fibrosis treatment.

RESULTS

HAb18G/CD147 is highly expressed on activated HSCs in the sinusoid. The positive rates of HAb18G/CD147 expression in human HBV-related liver cirrhosis, liver biopsy with HBV and liver adjacent to hemangioma were 95.6% (65/68), 14.8% (8/54) and 6.4% (8/125), respectively. HAb18G/CD147 expression was significantly correlated with the Child-Pugh grade (r=0.2848, p=0.0186) and with the expression of α-smooth muscle actin in HSCs (r=0.4434, p=0.0002) in liver cirrhosis. Transforming growth factor-β1 upregulated HAb18G/CD147 expression in LX-2 cells. Transfection of HAb18G/CD147 promoted the profibrogenic genes expression. In mouse liver fibrosis model, HAb18G/CD147 expression increased with the development of fibrogenesis and decreased during the liver fibrosis spontaneous recovery. The HAb18 targeting HAb18G/CD147 could attenuate liver fibrosis.

CONCLUSIONS

These data suggest that HAb18G/CD147 plays a role in HSC activation and is a potential therapeutic target in fibrosis/cirrhosis.

CD147/EMMPRIN: an effective therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is characterized by high resistance to conventional systemic therapies, rapid progression, easy metastasis and frequent recurrence. There is therefore an urgent requirement to develop novel systemic agents which specifically target hepatoma-associated antigen in the tumors of HCC patients. CD147, a transmembrane glycoprotein, is highly expressed by HCC cells and is strongly associated with HCC progression and prognosis. CD147 in HCC cells modulates HCC growth, promotes invasion and metastasis by stimulating adjacent fibroblasts and HCC cells to produce elevated levels of several extracellular matrix metalloproteinases (MMPs) in the HCC microenvironment. It is also involved in HCC angiogenesis and multidrug resistance (MDR). Clinical progress has been made in HCC treatment using CD147-directed monoclonal antibodies. Here, we give an overview of the literature regarding the molecular features and expression of CD147 in human HCC tissues. We specifically focus on the role of CD147 in HCC invasion and metastasis, as well as in angiogenesis and multidrug resistance. In addition, advances in therapeutic strategies targeting HCC CD147 are summarized.

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.

Hepatic artery injection of ¹³¹I-labelled metuximab combined with chemoembolization for intermediate hepatocellular carcinoma: a prospective nonrandomized study

PURPOSE

Hepatocellular carcinoma (HCC) is the fifth and seventh most common cause of cancer in men and women, respectively. Transcatheter arterial chemoembolization (TACE) is the standardized therapy for the intermediate stage of HCC. However, the 3-year overall survival remains low (<30 %) in these patients. Thus, there is a critical need for the development of treatment modalities to improve the survival rate. This study aimed to evaluate whether the combination of (131)I-metuximab with chemoembolization could improve treatment efficiency.

METHODS

Between January 2009 and January 2010, a prospective two-arm nonrandomized study was performed in patients with intermediate HCC. Of 138 patients, 68 (combination therapy group) received 132 courses of intraarterial (131)I-metuximab injections combined with chemoembolization (mean 1.94 per patient, median 2, range 1-2), followed by 152 sessions of TACE (mean 2.24 per patient, median 2, range 0-4). The remaining 70 patients (monotherapy group) received 296 sessions of TACE (mean 4.23 per patient, median 4, range 1-7).

RESULTS

The overall median survival times for the combination therapy group and the group treated only with TACE were 26.7 months (95 % CI 20.7-31.3 months) and 20.6 months (95 % CI 15.3-24.7 months), respectively. The combination therapy group had a significantly higher survival rate than the TACE-only group (P = 0.038). Age ≥65 years, serum albumin ≤35 g/l, and treatment category (combination therapy or TACE only) were independent prognostic factors for survival according to multivariate analysis.

CONCLUSION

The combination of (131)I-metuximab and chemoembolization extended survival in patients with intermediate HCC compared with TACE only, and was well tolerated by patients with Child-Pugh class A or B disease. This combination seems to be a promising treatment modality for patients with intermediate HCC.

EMMPRIN/CD147 up-regulates urokinase-type plasminogen activator: implications in oral tumor progression

Backgrounds

An elevated level of EMMPRIN in cancer tissues have been correlated with tumor invasion in numerous cancers including oral cavity and larynx. Although EMMPRIN's effect has been generally attributed to its MMP inducing activity, we have previously demonstrated in breast cancer model that EMMPRIN can also enhance invasion by upregulating uPA. In this study, the role of EMMPRIN in regulating uPA and invasion was investigated in oral squamous cell carcinoma (OSCC) progression.

Methods

Precancerous and invasive oral tumoral tissues were used as well as the corresponding cell lines, DOK and SCC-9 respectively. The paracrine regulation of uPA by EMMPRIN was investigated by treating culture cells with EMMPRIN-enriched membrane vesicles. UPA expression was analyzed by qPCR and immunostaining and the consequence on the invasion capacity was studied using modified Boyden chamber assay, in the presence or absence of EMMPRIN blocking antibody, the uPA inhibitor amiloride or the MMP inhibitor marimastat.

Results

OSCC tumors were shown to express more EMMPRIN and uPA compared to dysplastic lesions. The corresponding cell models, SCC-9 and DOK cells, displayed similar expression pattern. In both cell types EMMPRIN upregulated the expression of uPA as well as that of MMP-2 and MMP-9. EMMPRIN treatment led to a significant increase in cell invasion both in the invasive SCC-9 and in the less invasive dysplastic DOK cells, in an MMP and uPA dependent manner.

Conclusions

Our results suggest that the upregulation of uPA contributes to EMMPRIN's effect in promoting oral tumor invasion.

Expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and its expected roles in the bovine endometrium during gestation

Extracellular matrix metalloproteinase inducer (EMMPRIN) and its induced matrix metalloproteinases (MMPs) play a crucial role in tissue remodeling during the peri-implantation period. However, the role of EMMPRIN in the bovine placenta is still unclear. We have postulated that EMMPRIN might play a regulatory role in trophoblastic cell functions during gestation by itself or through the regulation of MMP expression. In this study, EMMPRIN mRNA was detected in the bovine placentome and interplacentome throughout gestation, and its expression was significantly higher in the cotyledon during late gestation. In situ hybridization showed that EMMPRIN mRNA was expressed in the caruncular epithelium and the cotyledonary epithelium, including binucleate cells. Western blot analysis detected a band representing a protein of approximately 65 kDa in the caruncular and cotyledonary tissues, and the intensity of its expression was increased in both of these tissues during late gestation. The expression levels of MMP-2 and MMP-14 in the bovine placenta were higher during late gestation, as was observed for EMMPRIN. Therefore, EMMPRIN might regulate trophoblastic cell functions, especially those of binucleate cells, through MMP expression in the bovine placenta.

EMMPRIN regulates cytoskeleton reorganization and cell adhesion in prostate cancer

BACKGROUND

Proteins on cell surface play important roles during cancer progression and metastasis via their ability to mediate cell-to-cell interactions and navigate the communication between cells and the microenvironment.

METHODS

In this study a targeted proteomic analysis was conducted to identify the differential expression of cell surface proteins in human benign (BPH-1) versus malignant (LNCaP and PC-3) prostate epithelial cells. We identified EMMPRIN (extracellular matrix metalloproteinase inducer) as a key candidate and shRNA functional approaches were subsequently applied to determine the role of EMMPRIN in prostate cancer cell adhesion, migration, invasion as well as cytoskeleton organization.

RESULTS

EMMPRIN was found to be highly expressed on the surface of prostate cancer cells compared to BPH-1 cells, consistent with a correlation between elevated EMMPRIN and metastasis found in other tumors. No significant changes in cell proliferation, cell cycle progression, or apoptosis were detected in EMMPRIN knockdown cells compared to the scramble controls. Furthermore, EMMPRIN silencing markedly decreased the ability of PC-3 cells to form filopodia, a critical feature of invasive behavior, while it increased expression of cell-cell adhesion and gap junction proteins.

CONCLUSIONS

Our results suggest that EMMPRIN regulates cell adhesion, invasion, and cytoskeleton reorganization in prostate cancer cells. This study identifies a new function for EMMPRIN as a contributor to prostate cancer cell-cell communication and cytoskeleton changes towards metastatic spread, and suggests its potential value as a marker of prostate cancer progression to metastasis.

EMMPRIN contributes to the in vitro invasion of human salivary adenoid cystic carcinoma cells

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a transmembrane glycoprotein that is involved in tumor invasion by stimulating matrix metalloproteinase (MMP) expression. Our previous immunohistochemical study found that the expression of EMMPRIN in salivary adenoid cystic carcinoma (SACC) was positively correlated with tumor perineural and perivascular invasion. The present study was designed to further investigate the role of EMMPRIN in the invasion of SACC. Western blot results showed that EMMPRIN was upregulated in the highly metastatic SACC cell line SACC-LM, compared to SACC-83, a SACC cell line with low metastatic ability. Blocking of EMMPRIN by its antibody significantly decreased the adhesion, secretion of MMP-2 and MMP-9, and invasion activity of SACC-LM cells in vitro (P<0.01). Co-cultures of SACC-LM cells with fibroblasts significantly produced elevated levels of MMP-2 and MMP-9, and promoted the in vitro invasion activity of SACC-LM cells, compared with cultures of SACC-LM cells alone (P<0.01). These results indicate that EMMPRIN may play an important role in the invasion of SACC by stimulating the expression of MMP-2 and MMP-9 in tumor and stromal cells.

HAb18G/CD147 promotes cell motility by regulating annexin II-activated RhoA and Rac1 signaling pathways in hepatocellular carcinoma cells

Tumor cells can move as individual cells in two interconvertible modes: mesenchymal mode and amoeboid mode. Cytoskeleton rearrangement plays an important role in the interconversion. Previously, we reported that HAb18G/CD147 and annexin II are interacting proteins involved in cytoskeleton rearrangement, yet the role of their interaction is unclear. In this study we found that the depletion of HAb18G/CD147 produced a rounded morphology, which is associated with amoeboid movement, whereas the depletion of annexin II resulted in an elongated morphology, which is associated with mesenchymal movement. The extracellular portion of HAb18G/CD147 can interact with a phosphorylation-inactive mutant of annexin II and inhibit its phosphorylation. HAb18G/CD147 inhibits Rho signaling pathways and amoeboid movement by inhibiting annexin II phosphorylation, promotes membrane localization of WAVE2 and Rac1 activation by way of the integrin-FAK-PI3K/PIP3 signaling pathway, and promotes the formation of lamellipodia and mesenchymal movement.

CONCLUSION

These results suggest that the interaction of HAb18G/CD147 with annexin II is involved in the interconversion between mesenchymal and amoeboid movement of hepatocellular carcinoma cells.

An efficient method for refolding the extracellular portion of CD147 from the total bacterial lysate

CD147 is a widely expressed transmembrane protein that mediates signal transduction, and it plays important roles in many physiological and pathological processes, such as tumor invasion and metastasis. The extracellular portion of CD147 (CD147(EC)) is responsible for its functional interactions with different signaling molecules. Due to the existence of two disulfide bonds, CD147(EC) is mainly expressed as an inclusion body in Escherichia coli. Here, we report a convenient rapid-dilution refolding protocol that enables the refolding of CD147(EC) efficiently from total bacterial lysate instead of pure inclusion bodies. Using this method, over 25 mg of CD147(EC) can be purified from 1 l of bacterial culture in M9 medium. The refolded CD147(EC) is well folded as characterized by nuclear magnetic resonance (NMR), and it can induce the expression of matrix metalloproteinase-9 in fibroblast cells. The described protocol is also applicable to the refolding of two immunoglobulin domains of CD147(EC) individually. Interestingly, we noticed that little protein was produced for the C-terminal immunoglobulin (Ig) domain of CD147(EC) by bacteria in M9 medium, even though it was overexpressed in Luria-Bertani (LB) medium. However, when the pH of the bacterial culture in M9 medium was adjusted in accordance with that in LB medium during growth, comparable expression level could be achieved.

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.

EMMPRIN and its ligand cyclophilin A as novel diagnostic markers in inflammatory cardiomyopathy

BACKGROUND

During inflammatory cardiomyopathy matrix metalloproteinases are crucially involved in cardiac remodeling. The aim of the present study was to investigate whether the "extracellular matrix metalloproteinase inducer" EMMPRIN (CD147) and its ligand Cyclophilin A (CyPA) are upregulated in inflammatory cardiomyopathy and may serve as diagnostic markers. Therefore, a series of 102 human endomyocardial biopsies were analyzed for the expression of EMMPRIN and CyPA and correlated with histological and immunohistological findings.

METHODS AND RESULTS

Endomyocardial biopsies were stained for EMMPRIN and CyPA in addition to standard histology (HE, Trichrom) and immunohistological stainings (MHC-II, CD68, CD3). 39 (38.2%) biopsies met the immunohistological criteria of an inflammatory cardiomyopathy. EMMPRIN, which was predominantly expressed on cardiomyocytes, was slightly (but significantly) upregulated in non inflammatory cardiomyopathies compared to normal histopathological findings and highly upregulated in inflammatory cardiomyopathy compared to both non inflammatory cardiomyopathy and normal histopathology. In contrast, CyPA reveals no enhanced expression in non inflammatory cardiomyopathies and a highly enhanced expression in inflammatory cardiomyopathy, where it is closely associated with leucocytes infiltrates. We found a strong correlation between both EMMPRIN and CyPA with the expression of MHC-II molecules (correlation coefficient 0.475 and 0.527, p<0.05). Moreover, we found a correlation for both EMMPRIN and CyPA with CD68 (correlation coefficient 0.393 and 0.387, p<0.05) and CD3 (correlation coefficient 0.360 and 0.235, p<0.05).

CONCLUSION

EMMPRIN is enhanced in both inflammatory and non inflammatory cardiomyopathies and can serve as a marker of myocardial remodeling. CyPA may represent a novel and specific marker for cardiac inflammation.

Hepatic arterial iodine-131-labeled metuximab injection combined with chemoembolization for unresectable hepatocellular carcinoma: interim safety and survival data from 110 patients

Few options are available to treat patients with hepatocellular carcinoma (HCC). It was tested whether the combination of iodine-131(¹³¹I)-metuximab with chemoembolization could improve outcomes in patients with intermediate HCC. Between April 2008 and April 2009, 110 patients with unresectable HCC were treated with 113 intra-arterial ¹³¹I-metuximab injections combined with chemoembolization (mean, 1.03 per patient; median, 1; range, 1-2), followed by 264 sessions of transcatheter arterial chemoembolization (mean, 2.4 per patient; median, 3; range, 1-6). The survival rates at 6, 12, and 18 months were 88.2%, 79.1%, and 57.4%, respectively, by the Kaplan-Meier method. Of these patients, 12% exhibited grade 3/4 bilirubin toxicity, 5% exhibited grade 3/4 white blood count toxicity, and 7% exhibited grade 3/4 platelet toxicity. Response rates based on World Health Organization and European Association for the Study of the Liver criteria were 42.73% and 61.82%, respectively. The combination of ¹³¹I-metuximab and chemoembolization appeared to extend survival in patients with unresectable HCC compared with historical controls, as well as being well tolerated by patients with Child-Pugh A and B. This combination may represent a promising treatment modality for patients with intermediate HCC.

Characterization of basigin isoforms and the inhibitory function of basigin-3 in human hepatocellular carcinoma proliferation and invasion

Basigin, which has four isoforms, plays an important role in invasion of hepatocellular carcinoma (HCC). Detailed transcriptional regulation and functions of the basigin isoforms have not been reported except in the case of the predominant isoform basigin-2, which act as inducer of matrix metalloproteinases (MMPs). Here we determined that basigin-2, basigin-3, and basigin-4 were the most abundant transcript variants in human cell lines. GeneRacer PCR and luciferase reporter assays showed that basigin-3 and basigin-4 were initiated from an alternative promoter. Basigin-3 and basigin-4 were widely expressed in various normal human tissues at the mRNA level and were upregulated in HCC tissues compared to in normal tissues. Western blotting and confocal imaging showed that glycosylated basigin-3 and basigin-4 were expressed and localized to the plasma membrane. However, in cultured cell lines, only native basigin-3, and not basigin-4, was detected at protein level. Overexpression of basigin-3 inhibited HCC cell proliferation, MMP induction, and cell invasion in vitro and in vivo. Bimolecular fluorescence complementation assays and nuclear magnetic resonance (NMR) analysis indicated that basigin-3 interacted with basigin-2 to form hetero-oligomers. In conclusion, we systematically investigated the alternative splicing of basigin and found that basigin-3 could inhibit HCC proliferation and invasion, probably through interaction with basigin-2 as an endogenous inhibitor via hetero-oligomerization.

Extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) as a novel regulator of myogenic cell differentiation

Matrix metalloproteinases (MMPs) are thought to play an important role in skeletal muscle cell growth and differentiation. In view of the MMP inducing function of EMMPRIN/CD147, its role in myogenic cell differentiation was investigated. EMMPRIN level increased during differentiation of both rat primary myoblasts derived from satellite cells and mouse C2.7 myogenic cells and was associated with an alteration in its molecular forms. In parallel, expression of pro-MMP-9 gradually decreased and that of pro-MMP-2 and active MMP-2 increased. While small interfering RNA (siRNA) inhibition of EMMPRIN expression accelerated cell differentiation, exogenously added recombinant EMMPRIN inhibited differentiation by an MMP-mediated mechanism, as the MMP inhibitor marimastat abrogated EMMPRIN's effect. Our results further suggest that EMMPRIN regulates differentiation through an MMP activation of transforming growth factor beta (TGFβ), a known inhibitor of myoblast's differentiation, as the increased activation and signaling of TGFβ by EMMPRIN was attenuated in the presence of marimastat. EMMPRIN inhibition may thus represent a novel strategy in the treatment of muscular degenerative disorders.

New strategy for large-scale preparation of the extracellular domain of tumor-associated antigen HAb18G/CD147 (HAb18GED)

HAb18G/CD147, a cancer-associated biomarker, can promote tumor growth, invasion and metastasis. Here, we established a new strategy to express the extracellular domain of HAb18G/CD147 (HAb18GED) by using the FRT/Flp-In recombinase-based site-directed integration system. Two clones expressing HAb18GED were established, and 600 mg HAb18GED was obtained with more than 95% purity. Our results showed that purified HAb18GED exhibited strong activities to stimulate the secretion of pro-MMP2 and MMP-2 and promote the invasion of HCC cells. Overall, our study effectively overcame the difficulty of large-scale HAb18GED preparation and laid a solid foundation for the further studies on structure and functions of HAb18G/CD147.

EMMPRIN promotes melanoma cells malignant properties through a HIF-2alpha mediated up-regulation of VEGF-receptor-2

EMMPRIN's expression in melanoma tissue was reported to be predictive of poor prognosis. Here we demonstrate that EMMPRIN up-regulated VEGF receptor-2 (VEGFR-2) in two different primary melanoma cell lines and consequently increased migration and proliferation of these cells while inhibiting their apoptosis. SiRNA inhibition of VEGFR-2 expression abrogated these EMMPRIN effects. EMMPRIN regulation of VEGFR-2 was mediated through the over-expression of HIF-2α and its translocation to the nucleus where it forms heterodimers with HIF-1β. These results were supported by an in vivo correlation between the expression of EMMPRIN with that of VEGFR-2 in human melanoma tissues as well as with the extent of HIF-2α localization in the nucleus. They demonstrate a novel mechanism by which EMMPRIN promotes tumor progression through HIF-2α/VEGFR-2 mediated mechanism, with an autocrine role in melanoma cell malignancy. The inhibition of EMMPRIN in cancer may thus simultaneously target both the VEGFR-2/VEGF system and the matrix degrading proteases to block tumor cell growth and invasion.

Up-regulated EMMPRIN/CD147 protein expression might play a role in colorectal carcinogenesis and its subsequent progression without an alteration of its glycosylation and mRNA level

PURPOSE

Extracellular matrix metalloproteinase inducer (EMMPRIN) was reported to involve in the invasion and metastasis of malignancies by regulating the expression of vascular endothelial growth factor (VEGF) in stromal and cancer cells. The study aimed to clarify the role of EMMPRIN expression in tumorigenesis and progression of colorectal carcinomas (CRC).

METHODS

EMMPRIN expression was examined on tissue microarray containing colorectal carcinomas, adenoma and non-neoplastic mucosa (NNM) by immunohistochemistry and in situ hybridization (ISH). Colorectal carcinoma cell lines (DLD-1, HCT-15, SW480 and WiDr) and tissues were studied for EMMPRIN expression by Western blot or RT-PCR, followed by sequencing.

RESULTS

All carcinoma cell lines showed EMMPRIN expression at both mRNA and protein levels. Two synonymous mutations were found in carcinoma cell lines at codon109 (GCT → GCC: Ala) or 179 (GAT → GAC: Asp). Frozen CRC tissues displayed higher EMMPRIN expression than paired NNM (P < 0.05). EMMPRIN expression was immunohistochemically stronger in colorectal high-grade adenoma, adenocarcinoma and metastatic carcinoma than non-neoplastic superficial epithelium and low-grade adenoma (P < 0.05). In contrast, its mRNA level was similar from colorectal NNM, adenoma to adenocarcinoma by ISH, in line with the findings of RT-PCR (P > 0.05). Immunohistochemically, EMMPRIN expression was positively correlated with tumor size, depth of invasion, vascular or lymphatic invasion, grade of infiltration (INF), ki-67 and VEGF expression of CRCs (P < 0.05). Among them, depth of invasion was an independent associated factor for EMMPRIN expression in CRCs (P < 0.05).

CONCLUSIONS

Up-regulated EMMPRIN protein expression might contribute to colorectal carcinogenesis without the alteration of its glycosylation and mRNA level. Aberrant EMMPRIN protein expression might promote growth or invasion of CRCs possibly through increased ki-67 expression and inducible angiogenesis via up-regulating VEGF expression.

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.

Annexin II promotes invasion and migration of human hepatocellular carcinoma cells in vitro via its interaction with HAb18G/CD147

HAb18G/CD147, a member of the immunoglobulin family enriched on the surface of tumor cells, is reported to be correlated with invasion, metastasis, growth, and survival of malignant cells. Here, we found that annexin II, a 36-kDa Ca(2+)- and phospholipid-binding protein and in vivo substrate for tyrosine kinase and PKC, is a new interaction protein of HAb18G/CD147 in human hepatocellular carcinoma (HCC) cells. In the present study, we explored the unclear role of annxin II in HCC invasion and migration and the interaction effects between HAb18G/CD147 and annexin II. Our data show that downregulation of annexin II in HCC cells significantly decreased the secretion of MMP, migration ability, and invasive potential, and affected the cytoskeleton rearrangement of tumor cells. The MMP-2 level and invasive potential of HCC cells were regulated by both annexin II and HAb18G/CD147. Also, interaction effects exist between the two molecules in tumor progression, including MMP-2 production, migration, and invasion. These results suggest that annexin II promotes the invasion and migration of HCC cells in vitro, and annexin II and HAb18G/CD147 interact with each other in the same signal transduction pathway working as a functional complex in tumor progression.

Evaluation of EMMPRIN and MMP-2 in the prognosis of primary cutaneous malignant melanoma

The aim of the study was to investigate whether the presence of matrix metalloproteinase-2 (MMP-2) and its inducer, extracellular matrix metalloproteinase inducer (EMMPRIN), in primary cutaneous malignant melanoma (PCMM) might help to predict patient prognosis. Immunohistochemical staining was performed on formalin-fixed, paraffin-embedded sections of PCMM from 150 patients. Association of clinical variables (gender, age, tumor location, thickness, Clark level and AJCC stage) with EMMPRIN and MMP-2 expression were analyzed by Fisher's exact test. Survival rates were subsequently estimated using the Kaplan-Meier method and compared using the log-rank test. The expression of EMMPRIN and MMP-2 was detected in 117/150 (78.0%) and 115/150 (76.7%) of patients with PCMM, respectively. Higher positive rates of both EMMPRIN and MMP-2 expression were significantly correlated with increased tumor thickness (both P=0.004), higher Clark level (P=0.02 and 0.03) and higher AJCC stage (both P=0.006). A significant correlation was found between the expression of EMMPRIN and MMP-2 in PCMM (r=0.89, P=0.01). Kaplan-Meier analysis demonstrated that patients who had EMMPRIN+/MMP-2+ expression had a significantly decreased 3-year disease-free survival (P=0.005) and 5-year overall survival (P=0.006). In multivariate analyses, tumor thickness and EMMPRIN+/MMP-2+ co-expression were the significant predictors of clinical outcome. EMMPRIN and MMP-2 may be independent biomarkers for disease recurrence and overall survival in patients with PCMM. A combined detection of EMMPRIN/MMP-2 co-expression may benefit us in prediction of a poor survival of PCMM.

EMMPRIN promotes angiogenesis through hypoxia-inducible factor-2alpha-mediated regulation of soluble VEGF isoforms and their receptor VEGFR-2

Extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) is thought to promote tumor angiogenesis mostly through its protease-inducing function and more recently by its ability to increase tumor cell expression of vascular endothelial growth factor (VEGF). In this study, we present evidence that EMMPRIN can promote angiogenesis by a direct effect on endothelial cells through a paracrine regulation of the VEGF/VEGF-receptor (VEGFR) system. Using human microvascular endothelial cell line-1 endothelial cells, we show that EMMPRIN selectively increased the soluble VEGF isoforms (121 and 165), but not the matrix-bound VEGF 189 form. In addition, EMMPRIN up-regulated the expression of VEGFR-2 without an effect on VEGFR-1. This increase in VEGFR-2 was responsible for the observed EMMPRIN stimulation of the migratory and tube formation capacity of endothelial cells. EMMPRIN's effects, which were matrix metalloproteinase and urokinase-type plasminogen activator independent, were mediated primarily through hypoxia-inducible factor-2alpha expression, also up-regulated by EMMPRIN. VEGFR-2 increase was also observed in vivo in a mouse model of xenograph tumors overexpressing EMMPRIN. These results suggest that in addition to increasing protease production, EMMPRIN may contribute to the formation of a reactive stroma also through the up-regulation of hypoxia-inducible factor-2alpha, VEGFR-2, and the soluble forms of VEGF in endothelial cells, thus directly regulating the angiogenic process.

EMMPRIN and its ligand cyclophilin A regulate MT1-MMP, MMP-9 and M-CSF during foam cell formation

Upon coincubation with platelets, CD34(+) progenitor cells have the potential to differentiate into foam cells, and thereby may promote the progression of atherosclerosis. The exact mechanism of MMP-regulation during the cellular differentiation process to foam cells is still unclear. Thus, we investigated the role of EMMPRIN (CD147) and its ligand cyclophilin A (CyPA) during foam cell formation originating from both monocytes/macrophages and CD34(+) progenitor cells.

METHODS AND RESULTS

Differentiation of CD34(+) progenitor to foam cells was analyzed in a coculture model of progenitor cells and platelets. While CD34(+) cells did not express EMMPRIN or MT1-MMP, mature foam cells strongly expressed EMMPRIN, which was associated with MT1-MMP expression as well as MMP-9. Gene silencing of EMMPRIN by siRNA during the cell differentiation process hindered not only the upregulation of MMPs (MT1-MMP, MMP-9), but also the secretion of the cytokine M-CSF. During the differentiation process CyPA was substantially released into the supernatant. The presence of the CyPA inhibitor NIM811 significantly reduced MMP-9 secretion during the differentiation process. Similar results were obtained using the classical pathway of foam cell formation by coincubating human macrophages with AcLDL. Additionally, the presence of soluble EMMPRIN ligands (CyPA, recombinant EMMPRIN) further enhanced MMP-9 secretion by mature foam cells. Consistently, CyPA and EMMPRIN were found in atherosclerotic plaques of ApoE-deficient mice by immunohistochemistry.

CONCLUSION

EMMPRIN is upregulated during the differentiation process from CD34(+) progenitor cells to foam cells, whereas its ligand, CyPA, is released. The CyPA/EMMPRIN activation pathway may play a relevant role in promoting the vulnerability of atherosclerotic plaques.

HAb18G (CD147), a cancer-associated biomarker and its role in cancer detection

AIMS

To evaluate HAb18G/CD147 as a cancer-associated biomarker using its monoclonal antibody HAb18.

METHODS AND RESULTS

On immunohistochemical analysis of 28 tissue microarrays and pathological sections of 1117 breast tissue samples, HAb18G/CD147 was expressed in carcinoma with an overall positivity rate of 67.76%, which was significantly higher than that in sarcomas (27.34%, P < 0.0001) and normal epithelial (5.18%, P < 0.0001) and fetal (2.67%, P < 0.0001) tissues. In epithelial tissues from 14 organs, the difference in HAb18G/CD147 expression between normal epithelium and the corresponding carcinoma was also significant (P < 0.05 for each pair). This expression in carcinoma was also found at the mRNA level, suggesting transcriptional level regulation of HAb18G/CD147 expression. In a retrospective study of 106 patients with infiltrating ductal carcinoma of the breast, the level of HAb18G/CD147 expression was positively correlated with tumour recurrence/metastasis (P = 0.0003) and negatively correlated with survival of breast cancer patients (P = 0.002). Multivariable Cox regression analysis showed that HAb18G/CD147 was an independent prognostic factor.

CONCLUSIONS

HAb18G/CD147 is significantly expressed in various cancers and appears to have prognostic significance, rendering it a possible cancer-associated biomarker for pathological diagnosis, prognostic evaluation, targeted therapy and radioimmunoimaging of a broad range of cancer types.

Expression of MMP9 and CD147 in invasive squamous cell carcinoma of the uterine cervix and their implication

Matrix metalloproteinase 9 (MMP9) and CD147 play a role in invasion and metastasis of many types of human malignancies. The correlation of the expression of MMP9 and CD147 with invasion and metastasis of invasive squamous cell carcinoma (SCC) of the uterine cervix has not been examined. In the present study, RT-PCR assay was used to detect the expression level of MMP9 mRNA semiquantitatively, and immunohistochemical stain was adapted to evaluate the score of CD147 on the cell membrane or in the cytoplasm of tumor cells of 65 cases of invasive squamous cell carcinoma of the uterine cervix and 21 cases of chronic cervitis tissues. MMP9 and CD147 expression in correlation with invasion, metastasis, and differentiation of invasive SCC of the uterine cervix was analyzed statistically. We found that MMP9 and CD147 expression was elevated significantly in tumor tissue compared to the control (cervical epithelium of chronic cervitis) (P<0.01). In the comparison of MMP9 and CD147 expression in 47 cases with lymph node metastasis and 18 cases without lymph node metastasis, there was a significantly higher expression of MMP9 and CD147 in the group with lymph node metastasis (P<0.05 for MMP9, P<0.01 for CD147). MMP9 expression was significantly higher in 24 cases of poor differentiation than in 41 cases of moderate differentiation (P<0.05). No difference was found in CD147 expression between poor and moderate differentiation (P>0.05). No significant difference in MMP9 and CD147 expression levels was obtained between 26 cases of FIGO stage I tumors and 39 cases of stage II tumors (P>0.05 for MMP9, P>0.05 CD147). There was no correlation between MMP9 or CD147 expression levels and the resected tumor size (P>0.05). The positive correlation (r=0.568, P<0.001) of MMP9 expression and CD147 score was seen in the tumor tissues of 65 cases. The data in this study show that MMP9 and CD147 expression are correlated with invasion, metastasis of squamous cell carcinoma of the uterine cervix, and that MMP9 expression is correlated with poor differentiation of invasive squamous cell carcinoma of the uterine cervix.

A soluble factor (EMMPRIN) in exudate influences knee motion after total arthroplasty

Few studies have been conducted to investigate biological factors that affect postoperative knee motion after total knee arthroplasty (TKA). The purpose of this study is to test the hypothesis that range of knee motion (ROM) at 4 weeks after TKA is correlated with the concentration of extracellular matrix metalloproteinase inducer (EMMPRIN) and transforming growth factor (TGF)-beta1 in the exudative fluid harvested from the joint after surgery. A prospective measurement study was conducted with 20 osteoarthritis patients who underwent TKA. At 48 h after surgery, the exudate was harvested from a closed drainage system. Enzyme-linked immunosorbent assay was performed to measure the concentration of TGF-beta1, EMMPRIN, MMP-1, 2, 9, tissue inhibitor of metalloproteinase-1, and Hyalunonan. Knee flexion angle was measured before and at 4 weeks after surgery. There was a significant correlation between the EMMPRIN levels and knee flexion angle (r = 0.557, p = 0.0148). Western blot analysis of the exudate showed a prominent band for EMMPRIN at 27 kDa. On the other hand, there was no correlation between the TGF-beta1 levels and the knee flexion angle. This study showed that EMMPRIN levels after TKA affect the postoperative ROM. As to clinical relevance, EMMPRIN in the exudate after TKA is a promising biological indicator to predict difficulty in restoring postoperative ROM.

Enhanced expression of Hab18g/CD147 and activation of integrin pathway in HCC cells under 3-D co-culture conditions

CD147 is reported to be correlated with the malignancy of some cancers, and its overexpression affects the progression of tumor. In the present study, we investigated the function of HAb18G/CD147, a member of CD147 family, on hepatocellular carcinoma (HCC) adhesion, invasion and metastasis in 3-dimensional (3-D) cell co-culture model. The results showed that the extracellular microenvironment could determine the cellular phenotypes and then affected the cellular functions. The expressions of HAb18G/CD147 in HCC cells and fibroblasts were both obviously elevated in 3-D co-culture model. The overexpression of HAb18G/CD147 increased MMPs' (MMP-2 and MMP-9) production (P < 0.01), and was obviously accompanied with enhanced expressions of paxillin, FAK and p-FAK in 3-D cell co-culture model. All the results suggest that HAb18G/CD147 plays an important role in HCC adhesion, invasion and metastasis mainly via modulating synthesis of MMPs and activating integrin signal pathways in fibroblasts and tumor cells themselves under the 3-D co-culture conditions.

The role of extracellular matrix metalloproteinase inducer protein in prostate cancer progression

Extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) is a multifunctional membrane glycoprotein overexpressed in many solid tumors, and involved in tumor invasion and angiogenesis. We investigated EMMPRIN expression in human prostate cancer (CaP) tissues and cells, and evaluated whether EMMPRIN expression is related to tumor progression and matrix metalloproteinase (MMPs) expression in human CaP. An immunohistochemical study using tissue microarrays of 120 primary CaPs of different grades and 20 matched lymph node metastases from untreated patients was performed. The association of EMMPRIN expression with clinicopathological parameters was evaluated. Co-immunolocalization for EMMPRIN and MMP-1, MMP-2 or MMP-9 in primary tumors was examined using confocal microscopy. Flow cytometry and immunoblotting were used to examine EMMPRIN expression in 11 metastatic CaP cell lines. Heterogeneous expression of EMMPRIN was found in 78/120 (65%) CaPs, correlated significantly with progression parameters including pre-treatment PSA level (P < 0.05) and increased with progression of CaP (Gleason score, P < 0.05; pathological stage, P < 0.01; nodal involvement, P < 0.05 and surgical margin, P < 0.05). Heterogeneous cytoplasmic MMP-1, MMP-2 and MMP-9 associated with EMMPRIN immunolabeling was observed, particularly in tumors with Gleason scores >3 + 4. Metastatic CaP cell lines, except DuCaP, expressed abundant EMMPRIN protein, indicating highly ( approximately 45 to approximately 65 kDa) and less ( approximately 30 kDa) glycosylated forms, although with no relationship to cells being either androgen responsive or nonresponsive. Our results suggest that EMMPRIN may regulate MMPs and be involved in CaP progression, and as such, could provide a target for treating metastatic CaP disease.

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.

Defining ETS transcription regulatory networks and their contribution to breast cancer progression

ETS factors are members of one of the largest families of evolutionarily conserved transcription factors, regulating critical functions in normal cell homeostasis, that when perturbed contribute to tumor progression. The well documented alterations in ETS factor expression and function during breast cancer progression result in pleiotropic effects manifested by the downstream effect on their target genes. Multiple ETS factors bind to the same regulatory sites present on target genes, suggesting redundant or competitive functions. Furthermore, additional events contribute to, or may be necessary for, target gene regulation. In order to advance our understanding of the ETS-dependent regulation of breast cancer progression and metastasis, this prospect article puts forward a model for examining the effects of simultaneous expression of multiple transcription factors on the transcriptome of non-metastatic and metastatic breast cancer. Compared to existing RNA profiles defined following expression of individual transcription factors, the anti- and pro-metastatic signatures obtained by examining specific ETS regulatory networks will significantly improve our ability to accurately predict tumor progression and advance our understanding of gene regulation in cancer. Coordination of multiple ETS gene functions also mediates interactions between tumor and stromal cells and thus contributes to the cancer phenotype. As such, these new insights may provide a novel view of the ETS gene family as well as a focal point for studying the complex biological control involved in tumor progression.