Matrilysin (MMP-7) promotes invasion of ovarian cancer cells by activation of progelatinase

Although matrilysin (MMP-7) is overexpressed in various malignancies, few studies have evaluated its role in epithelial ovarian cancer (EOC) invasion and metastasis. We report that the secretion of MMP-7 in EOC is stimulated significantly by vascular endothelial growth factor (VEGF) and interlukin-8 (IL-8). We also examined the in vivo expression of MMP-7 in EOC and its effects on the in vitro invasion and progelatinase activation. We report that MMP-7 is overexpressed in ovarian cancer cell lines and EOC surgical specimens. DOV13 cells incubated with active rhMMP-7 significantly increased cellular invasion and proMMP-2 activation. RhMMP-7 also showed the ability to activate proMMP-2 and proMMP-9 in immortalized ovarian epithelial cell (IOSE-29) conditioned medium. In addition, rhMMP-7 was able to activate progelatinase in a concentration-dependent manner in vitro. TIMP-2 or the generic MMP inhibitor-GM6001 inhibited both the activation of proMMP-2 and the increased invasion of DOV13 cells promoted by rhMMP-7. By incubation of MMP2-TIMP-2 complex with equal molar rhMMP-7, MMP-2 was dissociated from the complex and activated in a time-dependent manner, suggesting that TIMP-2 helps to keep the latency of MMP-2. TIMP-2 also showed inhibitory effects on the MMP-7 induced increase of gelatinolytic activity in DOV13 and IOSE-29 conditioned media. A strong co-localization of MMP-7 and MMP-2 was observed in DOV13 cells and ovarian carcinoma permanent tissue sections. These results indicate MMP-7 is overexpressed in malignant ovarian epithelium and suggest MMP-7 may facilitate tumor cell invasion in vivo partly through the induction of progelatinase activation.     

BAG3 (BCL2-associated athanogene 3) interacts with MMP-2 to positively regulate invasion by ovarian carcinoma cells

BAG3 (BCL2-associated athanogene 3) is a member of the BAG family proteins, which interact with and regulate Hsp70. Our aim in the present study was to correlate BAG3 expression in ovarian cancer with invasion and progression-free survival. We found that BAG3 interacts with MMP2 in cultured ovarian cancer cells, and that knockdown of BAG3 expression downregulated MMP2 expression and diminished cell motility and invasiveness. The incidence of BAG3 positivity was significantly higher at advanced clinical stages of ovarian cancer than at early stages. We suggest that BAG3 binds to MMP2 to positively regulate the process of cell invasion.     

乙酰肝素酶对卵巢癌细胞侵袭和黏附的影响

目的： 探讨乙酰肝素酶（heparanase,HPSE）在卵巢癌A2780细胞侵袭、转移中的作用。 方法： 构建携HPSE基因真核表达载体pcDNA3.1-HPSE,脂质体法将pcDNA3.1-HPSE和对照pcDNA3.1质粒转染至A2780细胞,G418筛选得稳定细胞株pcDNA3.1-HPSE-A2780和pcDNA3.1-A2780。MTT法和集落形成实验检测转染后A2780细胞的增殖;Matrigel侵袭、Transwell小室和黏附实验检测转染后A2780细胞的侵袭、迁移和黏附能力。 结果： 成功构建pcDNA3.1-HPSE载体,并转染入A2780细胞。pcDNA3.1-HPSE转染不影响A2780细胞的增殖（P＞0.05）,也不影响A2780细胞的迁移能力（P>0.05）。pcDNA3.1-HPSE转染促进A2780细胞的侵袭(0.477±0.024 vs 0.250±0.081,P=0.003),降低其黏附能力（0.728±0.089 vs 0518±0.080,P=0.002)。 结论： HPSE通过促进肿瘤细胞的侵袭和降低黏附,在卵巢上皮癌浸润、转移中发挥重要作用     

Nonsteroidal anti-inflammatory drugs inhibit growth of human neuroendocrine tumor cells via G1 cell-cycle arrest

Therapeutic options to inhibit growth of human NETs of the GEP system are limited. Since NSAIDs might provide an antiproliferative treatment alternative with acceptable toxicity, we examined the effects of different NSAIDs on growth and survival in a representative set of human GEP NET cell lines. Growth and apoptosis were determined based on cell numbers, cell-cycle analyses, kinase assays, DNA fragmentation and PARP cleavage. Expression of COX and cell cycle-regulatory molecules was examined by immunoblotting and reporter gene assays. Depending on the drug and cell line investigated, NSAID treatment resulted in profound growth inhibition of GEP NET cells. Growth-inhibitory effects were achieved with either COX-2 selective (NS398) or unselective (indomethacin, sulindac) compounds. Cell-cycle analyses documented a G1 arrest in NSAID-treated GEP NET populations. In addition, 100 microM sulindac or indomethacin induced apoptosis. All 3 COX inhibitors prevented CDK-2 activation. In parallel to the NSAID-mediated reduction of CDK-2 activity, p21(cip-1) promoter activity and cellular p21(cip-1) levels increased and p21(cip-1) was sequestered into CDK-2 complexes. Thus, the G1 arrest likely resulted from p21(cip-1)-dependent inhibition of CDK-2 activity. At therapeutically relevant concentrations, sulindac significantly reduced GEP NET cell numbers, whereas IFN-alpha and octreotide remained ineffective. The extent of growth inhibition in GEP NETs was comparable to the antiproliferative effects of sulindac in established NSAID-sensitive cell models. NSAIDs acted as potent antiproliferative agents in GEP NET cells via G1 cell-cycle arrest and might therefore offer a therapeutic alternative to current treatment modalities.     

Phosphatidylcholine-associated nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit DNA synthesis and the growth of colon cancer cells in vitro

The use of NSAIDs or COX-2 inhibitors for chemoprevention of colorectal cancer has been suggested for patients at high risk for this disease. However, the gastrointestinal side effects of traditional NSAIDs which consist of bleeding and ulceration, and the cardiovascular effects of COX-2 inhibitors may limit their usefulness. In preclinical studies, our laboratory has shown that the addition of phosphatidylcholine (PC) to the NSAIDs aspirin (ASA) or ibuprofen (IBU) results in a NSAID–PC with fewer GI side effects and also maintained or enhanced analgesic, anti-pyretic and anti-inflammatory efficacy over the unmodified NSAID. Because NSAID–PCs have not been tested for anti-cancer activity, in the present study, ASA–PC and IBU–PC were tested on the SW-480 human colon cancer cell line. SW-480 cells were incubated in media containing 1–5 mM NSAID or NSAID–PC for 2 days. Measurements were made of cell number, cell proliferation (DNA synthesis), and manner of cell death (necrosis and apoptosis). ASA and IBU reduced cell number in a dose-dependent manner with IBU showing a greater potency than ASA. The association of PC to the NSAID resulted in greater reductions of cell number for both NSAIDs. Furthermore, the NSAID–PC formulation had significantly greater efficacy and potency to inhibit cellular DNA synthesis than the unmodified NSAID. PC alone at the doses and times used had no effect on cell number in this cell line, but did have a small effect to reduce DNA synthesis. None of the drugs had a clear effect on cell death by necrosis. Only IBU and IBU–PC caused cell death by apoptosis in SW-480 cells. We conclude that NSAID–PCs have activity to impede the growth of colon cancer cells in vitro, which is due, in major part, to a marked reduction in DNA synthetic activity of these cells. This growth inhibitory effect appears to be independent of COX-2 activity, since it is known that SW-480 cells do not have this inducible COX isoform. Due to its greater efficacy in this model system, IBU–PC should be further evaluated as a chemopreventive agent that is safer for the GI tract than unmodified NSAID.     

Activation of Smad signaling enhances collagenase-3 (MMP-13) expression and invasion of head and neck squamous carcinoma cells

Squamous cell carcinoma (SCC) cells of the head and neck specifically express collagenase-3 (matrix metalloproteinase-13 (MMP-13)), the expression of which correlates with their invasion capacity. Transforming growth factor-beta (TGF-beta) enhances MMP-13 and collagenase-1 (MMP-1) expression and invasion of SCC cells via p38 mitogen-activated protein kinase. Here, we have examined the role of Smad signaling in regulating MMP-13 expression and in invasion of head and neck SCC cells. Treatment with TGF-beta resulted in activation of Smad2 and Smad3 in SCC cells, but had no effect on their proliferation or viability. Basal activation of Smad3 and p38 was noted in SCC cells without exogenous TGF-beta stimulation, and adenoviral delivery of Smad7 and dominant-negative Smad3 inhibited p38 activation in these cells. Adenoviral overexpression of Smad3 augmented the upregulatory effect of TGF-beta on MMP-13 expression by SCC cells. Disruption of Smad signaling by adenoviral expression of kinase-defective TGF-beta type I receptor (activin-receptor-like kinase-5), Smad7, and dominant-negative Smad3 potently suppressed the basal and TGF-beta-induced expression of MMP-13 and MMP-1 in SCC cells, and inhibited their basal and TGF-beta-induced invasion through Matrigel and type I collagen. Adenoviral overexpression of Smad7 in cutaneous and oral SCC cells significantly inhibited their implantation in skin of SCID mice and growth of xenografts in vivo, as compared to LacZ adenovirus-transduced control cells. Together, these results show that Smad signaling plays an important role in promoting the invasive phenotype of human head and neck SCC cells by upregulating their collagenase expression.     

Induction of matrix metalloproteinase-1 (MMP-1) during epidermal invasion of the stroma in human skin organ culture: keratinocyte stimulation of fibroblast MMP-1 production.

Organ cultures of human skin were incubated for 8 days under growth factor-free conditions or exposed to 10 ng ml(-1) of human recombinant epidermal growth factor (EGF) during the incubation period. Normal histological features were preserved in the absence of growth factor, while epithelial cells underwent a proliferative response and invaded the underlying stroma in the presence of exogenous EGF. The same concentrations of EGF that induced stromal invasion also resulted in up-regulation of matrix metalloproteinase-9 (MMP-9; 92-kD gelatinase B) in organ culture and keratinocyte monolayer culture, and expression of MMP-1 (interstitial collagenase) in organ culture and fibroblast monolayer culture. When skin organ cultures were exposed to a potent, irreversible EGF-receptor tyrosine kinase (EGF-RTK) antagonist along with EGF, abnormal histological features were reversed, and MMP-9 production was suppressed. In contrast, EGF-RKT antagonism had only a modest inhibitory effect on MMP-1 production. Culture fluid from keratinocytes grown in monolayer culture stimulated fibroblast proliferation and MMP-1 elaboration. Treatment of fibroblasts with the same EGF-RTK antagonist inhibited keratinocyte-induced fibroblast proliferation but had only a modest inhibitory effect (approximately 20% inhibition) on MMP-1 production. In contrast, treatment of dermal fibroblasts with Interleukin-1 Receptor Antagonist had no effect on keratinocyte-induced fibroblast growth but strongly inhibited MMP-1 production (greater than 70% inhibition). These data indicate that stromal invasion by epithelial cells in EGF-treated skin is associated with events occurring in both the epidermis and dermis. The direct effect of the exogenous growth factor appears to be primarily on the epidermis. Dermal events reflect, at least in part, a response to factors elaborated in the epidermis.     

Non-steroidal anti-inflammatory drugs inhibit cellular proliferation and upregulate cyclooxygenase-2 protein expression in endometrial cancer cells

We determined the effects of several non-steroidal anti-inflammatory drugs (NSAIDs), aspirin (acetylsalicylic acid, ASA), indomethacin and a cyclooxygenase-2 (COX-2)-selective inhibitor (NS398), on cellular proliferation and regulation of COX-2 protein expression in endometrial cancer cells in vitro, and investigated their modes of action. All three NSAIDs markedly inhibited the proliferation of Ishikawa, HEC-1A and AN3CA endometrial cancer cell lines in a time- and concentration-dependent manner. ASA and indomethacin triggered apoptosis in cells of all three lines through release of cytosolic cytochrome c, activation of caspase-9 and-3, and cleavage of poly(ADP-ribose) polymerase (PARP), but NS398 induced minimal apoptosis only in Ishikawa cells. ASA altered the cell cycle distribution, with G2/M phase accumulation of cells, and induced overexpression of Ki-67 protein. Both ASA and indomethacin reduced the protein levels of Bcl-2 and Bcl-xl, but upregulated those of Bax and Bcl-xs. COX-2 protein expression and PGE(2) production were upregulated by ASA and indomethacin in all three cell lines. However, NS398 did not alter COX-2 protein expression or PGE(2) production in these cells. These results indicate that NSAIDs inhibit proliferation of endometrial cancer cells independently of the reduction of COX-2 protein expression. A cytochrome c-dependent apoptotic pathway and/or cell cycle arrest may contribute to the inhibitory effects of these NSAIDs.     

Hypoxia stimulates breast carcinoma cell invasion through MT1-MMP and MMP-2 activation

The process of cancer cell invasion involves degradation of the extracellular matrix (ECM) by proteases, integrin adhesion and cell motility. The role of ECM degrading proteases on the hypoxia-induced invasion of breast carcinoma cells was investigated. Hypoxia markedly increased the invasion capacity of MDA-MB-231 and MDA-MB-435 breast carcinoma cell lines. Matrix metalloproteinase (MMP) inhibitors blocked the hypoxia-induced invasion, whereas other protease inhibitors had no effect. Antibodies or siRNAs blocking either membrane type-1 MMP (MT1-MMP) or MMP-2 were effective in reducing the hypoxia-induced invasion. Serum-free reconstitution experiments confirmed the involvement of the MT1-MMP/MMP-2/tissue inhibitor of metalloproteinase-2 complex in this hypoxia-induced response. Overexpression of MT1-MMP in a poorly invasive breast cancer cell line, T47-D, promoted hypoxia-induced invasion and MMP-2 activation. Cell surface accumulation and activation of MT1-MMP without apparent regulation at the mRNA or protein levels indicated a post-translational adaptive response to hypoxia. Inhibition of the small GTPase RhoA eliminated the hypoxia-induced invasion and blocked the localization of MT1-MMP to the plasma membrane. Zymographic and molecular analysis of human breast tumors showed a strong correlation between hypoxic microenvironments and MMP-2 activation without changes in MT1-MMP expression. Our studies suggest that hypoxic tumor microenvironments promote breast cancer invasion through an MT1-MMP-dependent mechanism.     

Geranylgeranylacetone inhibits lysophosphatidic acid-induced invasion of human ovarian carcinoma cells in vitro

BACKGROUND: Lysophosphatidic acid (LPA) induced a dose-dependent increase of cancer cell invasion by promoting Rho/Rho-associated kinase signaling. Prenylation of Rho is essential for regulating cell growth, motility, and invasion. Geranylgeranylacetone (GGA), an isoprenoid compound, is used clinically as an antiulcer drug. Recent findings suggested that GGA might inhibit the small GTPase activation by suppressing prenylation. The authors hypothesized that the anticancer effects of GGA result from the inhibition of Rho activation. METHODS: The authors examined the effect of GGA using an in vitro invasion assay in human ovarian carcinoma cells, and analyzed the mechanism of the GGA effect on Rho activation, stress fiber formation and focal adhesion assembly, which are essential processes for cell invasion. RESULTS: The induction of ovarian carcinoma cell invasion by LPA was inhibited by the addition of GGA in a dose-dependent manner. Treatment of cancer cells with GGA resulted in inactivation of Rho, changes in cell morphology, loss of stress fiber formation and focal adhesion assembly, and the suppression of tyrosine phosphorylation of focal adhesion proteins. The effect of GGA on cancer cells was partially prevented by the addition of geranylgeraniol, which is an intermediate of geranylgeranyl pyrophosphate and compensates geranylgeranylation of Rho. CONCLUSIONS: The inhibition of LPA-induced invasion by GGA was, at least in part, derived from suppressed Rho activation by preventing geranylgeranylation.     

Nonsteroidal anti-inflammatory drugs (NSAIDs) and mammographic density

Mammographic density has been established as a strong risk factor for breast cancer while use of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) has been associated with a reduction in risk of breast cancer. The hypothesis is that NSAIDs reverses the expression of prostaglandin E₂, thereby reducing the local production of estrogens. This report describes the differences in mammographic densities by duration of NSAID use in a multiethnic population. Information for this analysis was available from two previous investigations: a nutritional intervention study with 218 women and a nested case-control study of breast density with 1274 women. On the basis of self-reported medication use from a questionnaire common to both investigations, women were categorized into no use, up to 1 year, 2–5 years, 6–10 years, and 11+ years. Screening mammograms were assessed for density using a computer-assisted method. We applied general linear models to calculate mean percent densities for each medication use category while adjusting for covariates. The analysis of the overall study population did not show a significant association between total NSAID use and mammographic density. Contrary to our hypothesis, women with long-term total NSAID use had non-significantly higher densities than non-users. In addition, the results differed by menopausal status. Whereas the trend of higher densities with longer duration of total NSAID use was significant among postmenopausal women, breast density was slightly lower among premenopausal women with long-term NSAID use. Experimental studies need to be performed to study the effect, if any, of NSAID use on breast density.     

肝细胞癌组织中MMP-2的表达与侵袭转移的关系

目的:探讨人肝细胞性肝癌(hepatocellularcarcinoma,HCC)中基质金属蛋白酶2(matrixmetalloproteinase2,MMP2)的表达与其侵袭转移的关系。方法:用半定量逆转录PCR(RTPCR)方法检测癌、癌旁组织及正常组织中MMP2mRNA的表达;用免疫组织化学方法检测癌、癌旁组织及正常组织中MMP2蛋白质的表达。结果:MMP2在肝癌中的表达高于癌旁组织和正常组织,差异有统计学意义,P<0.05;癌旁组织和正常组织中MMP2的表达差异无统计学意义,P>0.05。癌组织中MMP2的表达与术后复发时间呈负相关,P=0.013,R2=0.842;与病理学分级呈正相关,P=0.000,R2=0.797。癌组织中MMP2的表达与肝外转移呈正相关,P=0.003,R2=0.834。癌旁组织中MMP2的表达与术后复发时间呈负相关,P=0.021,R2=0.877。结论:MMP2与肿瘤的分化程度、侵袭、转移能力和复发倾向相关。在临床中可望作为肿瘤分化、复发和转移的评估指标之一。     

肝细胞癌组织中MMP-2的表达与侵袭转移的关系

OBJECTIVE：To investigate the association between MMP-2 expression of hepatocellular carcinoma （HCC） and its invasion and metastasis. METHODS： Semi-quantitative RT-PCR and immunohistochemical analysis technology were used to detect MMP-2 mRNA expression and MMP-2 protein expression respectively in HCC, non-HCC liver tissue samples and normal liver tissue samples. RESULTS： The level of MMP-2 expression in HCC was higher than that in adjacent non-HCC liver tissue and in normal liver tissue and the difference was statistically significant, P〈0.05. and the difference of MMP-2 expression between adjacent non-HCC liver tissue and normal liver tissue had no statistical significance, P〉0. 05. MMP-2 expression in HCC had an inverse correlation with recurrence after surgical treatment, P=0.013, R^2=0.842, and a posi- tive correlation with pathological grade, P = 0. 000, R^2 = 0. 797. There was a positive correlation between MMP-2 expression in HCC and extrahepatie metastasis, P=0. 003, R^ =0. 834. Significant inverse correlation was found between MMP-2 expression in adjacent non-HCC liver tissue and extrahepatie metastasis, P=0. 021, R^2= 0. 877. CONCLUSIONS： MMP-2 has an association with degree of tumor differentiation, capability of invasion and metastasis and tendency of recurrence. MMP-2 way be one of indexes of differentiation, recurrence and metastasis.     

Silencing of IQGAP1 by shRNA inhibits the invasion of ovarian carcinoma HO-8910PM cells in vitro

Background

IQGAP1 is a scaffolding protein and overexpressed in many human tumors, including ovarian cancer. However, the contribution of IQGAP1 to invasive properties of ovarian cancer cells remains unknown. Here, we investigated the effect of IQGAP1-specific short hairpin RNA (shRNA) expressing plasmids on metastatic potential of ovarian cancer HO-8910PM cells.

Methods

We used RT-PCR and Western blot analysis to characterize expression of IQGAP1 in three human ovarian cancer-derived cell lines SK-OV-3, HO-8910 and HO-8910PM. We then determined whether expression of endogenous IQGAP1 correlated with invasive and migratory ability by using an in vitro Matrigel assay and cell migration assay. We further knocked down IQGAP1 using shRNA expressing plasmids controlled by U1 promoter in HO-8910PM cells and examined the proliferation activity, invasive and migration potential of IQGAP1 shRNA transfectants using MTT assay, in vitro Matrigel-coated invasion assay and migration assay.

Results

IQGAP1 expression level seemed to be closely associated with the enhanced invasion and migration in ovarian cancer cell lines. Levels of both IQGAP1 mRNA and protein were significantly reduced in HO-8910PM cells transfected with plasmid-based IQGAP1-specific shRNAs. RNAi-mediated knockdown of IQGAP1 expression in HO-8910PM cells resulted in a significant decrease in cell invasion and migration.

Conclusion

Our findings support the hypothesis that IQGAP1 promotes tumor progression and identify IQGAP1 as a potential therapeutic strategy for ovarian cancer and some other tumors with over-expression of the IQGAP1 gene.     

Anti-tumor effect of non-steroidal anti-inflammatory drugs on human ovarian cancers

Many reports have demonstrated that non-steroidal anti-inflammatory drugs (NSAIDs) suppress malignant transformation and tumor growth, and some NSAIDs are expected to be new anti-cancer agents. In this study, we examined the anti-tumor effects of the non-specific cyclooxygenase (COX) inhibitors aspirin and piroxicam, and the selective COX-2 inhibitor meloxicam on xenotransplanted ovarian cancer. Tumor growth and survival were compared in female nu/nu mice, xenografted with subcutaneous OVCAR-3 tumors or with intraperitoneal DISS tumors and treated with aspirin (200 ppm in diet, everyday), piroxicam (150 ppm in diet, everyday) or meloxicam (162 ppm in diet, everyday). Al, of the agents tested significantly suppressed the growth of OVCAR-3 tumors xenotransplanted subcutaneously as compared to the control. There was a significant difference in inhibition of OVCAR-3 tumor growth between meloxicam and aspirin treatment. Meloxicam and piroxicam treatment significantly prolonged survival of mice with malignant ascites derived from DISS cells as compared to control and aspirin treatment. Mice treated with meloxicam survived significantly longer than those treated with piroxicam. There was no significant difference in survival between control and aspirin treatment. Necropsy revealed that one of the 6 cancer-bearing mice treated with piroxicam suffered from stomach perforation. These results indicate that a selective COX-2 inhibitor produces greater anti-tumor effect against ovarian cancer than a nonselective COX inhibitor and that meloxicam may have a potential of leading to a novel therapeutic strategy against ovarian cancer.     

基质金属蛋白酶-2及基质金属蛋白酶-9的表达与胆囊癌转移、浸润的关系

目的 探讨胆囊癌组织中基质金属蛋白酶—2(MMP—2)及基质金属蛋白酶—9(MMP—9)的表达及其与胆囊癌浸润、转移的关系。方法 选取手术切除的胆囊癌标本42例及慢性胆囊炎标本15例，采用免疫组织化学的方法(SABC法)检测MMP—2及MMP—9蛋白的表达。并结合临床病理学指标进行统计学处理分析。结果 胆囊癌组织中MMP—2及MMP—9的阳性表达率显高于慢性胆囊炎。低分化及末分化组MMP—2的阳性率显性高于高分化组及中分化组。浆膜层浸润组、淋巴结转移组及肝脏转移组MMP—2的阳性率分别显性高于无浆膜层浸润组、无淋巴结转移组及无肝脏转移组。浆膜层浸润组及淋巴结转移组MMP—9的阳性率显高于无浆膜层浸润组及无淋巴结转移组。胆囊癌组织中MMP—2和MMP—9的表达有显的相关性。(P＜0．05)．二同时阳性表达组其浆膜层浸润、淋巴结和肝脏转移发生率显高于其中之一或均阴性组(P＜0．05)。结论 MMP—2的表达与胆囊癌的分化、浸润、淋巴结及肝脏转移密切相关。MMP—9的表达与胆囊癌浸润及淋巴结转移密切相关。MMP—2和MMP—9在胆囊癌组织中表达正相关，在胆囊癌的侵袭和转移过程中起协同作用。     

Synthetic emmprin peptides inhibit tumor cell-fibroblast interaction-stimulated upregulation of MMP-2 and tumor cell invasion

Stromal cells are the main source of matrix metalloproteinases (MMPs) in human carcinoma tissues. Emmprin is a glycosylated transmembrane protein containing two immunoglobulin (Ig) domains that is expressed in carcinoma cells and stimulates MMP production by adjacent stromal cells. The first Ig domain (ECI) of emmprin contains the biologically active site. We investigated whether synthetic peptides carrying a partial ECI sequence could inhibit emmprin activity. Only the second peptide (emp#2), which contains a putative N-glycosylation site sequence, inhibited emmprin-stimulated production of MMP-2 in co-cultures of fibroblasts and several different human tumor cells types, including carcinoma, sarcoma, melanoma, leukemia and glioma cells. Moreover, emp#2 significantly inhibited the invasive activity of glioblastoma cells promoted by interaction with fibroblasts. Perturbation of emmprin activity by this peptide may have potential therapeutic uses in the prevention of MMP-2-dependent cancer invasion.