EMMPRIN-mediated MMP regulation in tumor and endothelial cells

Tumor invasion and metastasis are multistep processes which require extracellular matrix remodeling by proteolytic enzymes such as matrix metalloproteinases (MMPs). The production of these enzymes is stimulated by many soluble or cell-bound factors. Among these factors, extracellular matrix metalloproteinase inducer (EMMPRIN) is known to increase in vitro stromal cell production of MMP-1, MMP-2 and MMP-3. In this study, we demonstrated that EMMPRIN-transfected MDA-MB-436 tumor cells displayed a more invasive capacity than vector-transfected cells in a modified Boyden chamber invasion assay. Using gelatin zymography and protein analyses, we showed that EMMPRIN-transfected cancer cells produced significantly more latent and active MMP-2 and MMP-3 than vector-transfected cancer cells. We found that EMMPRIN did not regulate MMP-1, MMP-9, membrane type-1 MMP (MT1-MMP) expression and had also no effect on the production of the specific tissue inhibitors of MMPs (TIMPs), TIMP-1 and TIMP-2. We also demonstrated that tumor-derived EMMPRIN stimulated MMP-1, -2, and -3 without modification of MMP-9, MT1-MMP, TIMP-1 and TIMP-2 production in human umbilical vein endothelial cells (HUVEC). These data provide support for the role of EMMPRIN in tumor invasion, metastasis, and neoangiogenesis by stimulating extracellular matrix remodeling around tumor cell clusters, stroma, and blood vessels. This revised version was published online in July 2006 with corrections to the Cover Date.     

A role for endothelial-derived matrix metalloproteinase-2 in breast cancer cell transmigration across the endothelial-basement membrane barrier

Invasive cancer cells utilize matrix metalloproteinases (MMPs) to degrade the extracellular matrix and basement membrane in the process of metastasis. Among multiple members of the MMP family, the gelatinase MMP-2 has been implicated in the development and dissemination of malignancies. However, the cellular source of MMP-2 and its effect on metastatic extravasation have not been well characterized. The objective of this study was to test the hypothesis that active MMP-2 derived from endothelial cells facilitated the transmigration of breast cancer cells across the microvascular barrier. Gelatin zymography was used to assess latent and active MMP-2 production in conditioned media from MDA-MB-231 human breast cancer cells, human lung microvascular endothelial cells (HLMVEC) and co-culture of these two cells. Transmigrated cancer cells were measured during MMP-2 knockdown with siRNA and pharmacological inhibition of MMP activity with OA-HY. The results showed consistent MMP-2 secretion by the HLMVECs, whereas a low level production was seen in the MDA-MB-231 cells. Inhibition of MMP-2 expression or activity in HLMVECs significantly attenuated the transmigration of MDA-MB-231 cells across an endothelial monolayer barrier grown on a reconstituted basement membrane. The data provide evidence supporting a potential role for the endothelial production of MMPs in promoting cancer cell extravasation. We suggest that the interaction between malignant cells and peritumoral benign tissues including the vascular endothelium may serve as an important mechanism in the regulation of tumor invasion and metastasis.     

Tumorigenic potential of extracellular matrix metalloproteinase inducer

Extracellular matrix metalloproteinase inducer (EMMPRIN), a glycoprotein present on the cancer cell plasma membrane, enhances fibroblast synthesis of matrix metalloproteinases (MMPs). The demonstration that peritumoral fibroblasts synthesize most of the MMPs in human tumors rather than the cancer cells themselves has ignited interest in the role of EMMPRIN in tumor dissemination. In this report we have demonstrated a role for EMMPRIN in cancer progression. Human MDA-MB-436 breast cancer cells, which are tumorigenic but slow growing in vivo, were transfected with EMMPRIN cDNA and injected orthotopically into mammary tissue of female NCr nu/nu mice. Green fluorescent protein was used to visualize metastases. In three experiments, breast cancer cell clones transfected with EMMPRIN cDNA were considerably more tumorigenic and invasive than plasmid-transfected cancer cells. Increased gelatinase A and gelatinase B expression (demonstrated by in situ hybridization and gelatin substrate zymography) was demonstrated in EMMPRIN-enhanced tumors. In contrast to de novo breast cancers in humans, human tumors transplanted into mice elicited minimal stromal or inflammatory cell reactions. Based on these experimental studies and our previous demonstration that EMMPRIN is prominently displayed in human cancer tissue, we propose that EMMPRIN plays an important role in cancer progression by increasing synthesis of MMPs.     

Expression of gelatinase B and the extracellular matrix metalloproteinase inducer EMMPRIN in benign and malignant pigment cell lesions of the skin.

By the degradative effect on basement membrane collagen type IV, matrix metalloproteinases (MMPs) or gelatinases are important in the early invasion of malignant tumors. These enzymes may be released by the tumor cells themselves or may be derived from nearby fibroblasts that have been stimulated by the extracellular MMP inducer EMMPRIN. We studied the distribution of 92-kd gelatinase B (MMP-9) and of EMMPRIN in 33 benign and 41 malignant, paraffin-embedded pigment cell lesions using immunohistochemistry and monoclonal antibodies. In benign pigment cell lesions, EMMPRIN but not gelatinase B was expressed in cellular blue nevi whereas all other benign lesions, including common blue nevi, were negative. In malignant melanomas (MMs), both gelatinase B and EMMPRIN were variably expressed in the pure and invasive radial growth phase but not in the vertical growth phase. All lentigo maligna cases and all metastatic lesions were negative. Of MMs with thickness < 1.6 mm, 63% expressed gelatinase B and 70% expressed EMMPRIN, whereas in MMs with > 1.6 mm thickness, only 10% expressed gelatinase B and only 25% expressed EMMPRIN. We conclude that early invasion of MM is associated with de novo expression of gelatinase B and EMMPRIN by neoplastic melanocytes. Expression of EMMPRIN and MMP-9 may be partly responsible for the stromal changes observed in thin MM. Their absence in the vertical growth phase and in metastatic lesions suggests that other factors are involved in tissue degradation during later stages of tumor progression in MM. The lack of both gelatinase B and EMMPRIN in lentigo maligna may contribute to the indolent behavior of this type of pigment cell lesion.     

Differential expression of extracellular matrix metalloproteinase inducer (CD147) in normal and ulcerated corneas: role in epithelio-stromal interactions and matrix metalloproteinase induction

Extracellular matrix metalloproteinase inducer (EMMPRIN) was originally identified on the tumor cell surface as an inducer of matrix metalloproteinase (MMP) production in neighboring fibroblasts. Here we demonstrate a role for EMMPRIN in MMP induction during corneal wound healing. MMP and EMMPRIN expression was analyzed in normal and ulcerated human corneas, as well as in corneal epithelial and stromal cells in culture using confocal microscopy, zymography, immunoblots, and real-time polymerase chain reaction. In normal cornea EMMPRIN was predominantly expressed in the epithelium but was markedly induced in the anterior stroma of ulcerated corneas. This coincided with MMP-2 induction that co-localized with EMMPRIN at the epithelio-stromal boundary. The role of epithelial-stromal interaction in MMP induction was investigated in an in vitro co-culture system and demonstrated an induction and co-localization of EMMPRIN and MMP-2 in the fibroblasts at the interface with epithelial cells. Direct contact of fibroblasts with EMMPRIN-containing purified epithelial cell membranes also induced MMP-1, MMP-2, and EMMPRIN and this was inhibited by a blocking anti-EMMPRIN antibody, suggesting that EMMPRIN was primarily responsible for this induction. These findings, and the up-regulation of EMMPRIN by epidermal growth factor and transforming growth factor-beta, demonstrate a role for EMMPRIN in wound healing and suggest that sustained local up-regulation of EMMPRIN and MMPs in chronic situations in which healing is delayed may lead to excessive matrix degradation and corneal melts.     

Induction of membrane-type matrix metalloproteinase 1 (MT1-MMP) expression in human fibroblasts by breast adenocarcinoma cells

Membrane-type matrix metalloproteinase 1 (MT1-MMP) has been recently described as an activator of proMMP-2 (MMP-2) which is involved in tumor invasion. We have shown by in situ hybridization that MT1-MMP is produced by stromal cells in close contact to preinvasive and invasive tumor cells of breast carcinomas. Of particular interest was the observation that some fibroblasts express this enzyme in focal areas in preinvasive lesions, suggesting that particular tumor cells may stimulate fibroblasts to produce MT1-MMP. We have therefore compared the ability of two different breast cancer cell lines, one non-invasive (MCF7) and one invasive (MDA-MB-231) to stimulate MT1-MMP production in human fibroblasts with consequent proMMP-2-activation. The MDA-MB-231 conditioned medium induced MT1-MMP mRNAs in human fibroblasts and a parallel activation of proMMP-2 whereas MCF7 conditioned medium did not have any effect. These results suggest the existence of soluble factor(s) secreted by invasive or some preinvasive breast tumor cells which stimulate fibroblasts to produce and activate MMPs, and emphasize the cooperation between cancer and stromal cells in tumor invasion.     

Inhibition of cyclooxygenase-2 suppresses the invasiveness of oral squamous cell carcinoma cell lines via down-regulation of matrix metalloproteinase-2 production and activation

Increased cyclooxygenase (COX-2) expression in tumors is known to be correlated with tumor invasion, angiogenesis, resistance to apoptosis, and suppression of host immunity. We previously reported that the invasiveness of human oral squamous cell carcinoma (OSCC) cell lines NA and HSC-4 was suppressed by treatment with either NS-398, a selective COX-2 inhibitor, or COX-2 antisense oligonucleotide (AS). In the present study, to explore the effects of COX-2 inhibition on the interaction between cancer cells and fibroblasts, we examined the effects of these anti-COX-2 reagents on the expression of matrix metalloproteinases (MMPs) in fibroblast cell lines WI-38 and MRC-5. Western blotting and enzyme-linked immunosorbent assay revealed that NS-398 and COX-2 AS down-regulated the expression and secretion of MMP-2 and the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) in human fibroblast cell lines. Furthermore, invasion activity of OSCC cells was down-regulated by the addition of culture supernatant from fibroblasts treated with anti-COX-2 reagents in a Matrigel^® invasion assay. These results suggest that selective COX-2 inhibition suppresses the invasion activity of OSCC cells via down-regulation of an MMP-2-activating mechanism involving TIMP-2 and production of the MMP-2 protein by an interaction between cancer cells and stromal fibroblasts. Genetic or pharmacological inhibition of COX-2 may therefore be a beneficial strategy in the treatment of OSCC.     

EMMPRIN基因沉默对巨噬/泡沫细胞中MMP-9表达及单核细胞迁移能力的影响

目的:观察细胞外基质金属蛋白酶诱导因子(EMMPRIN)基因沉默对巨噬/泡沫细胞中基质金属蛋白酶9(MMP-9)表达以及单核细胞迁移能力的影响。方法:根据RNA干扰原理,设计合成EMMPRIN-siR-NA。通过荧光定量PCR和Western blotting观察巨噬、泡沫细胞中EMMPRIN基因和蛋白被抑制情况。采用West-ern blotting观察特异性抑制EMMPRIN表达对巨噬、泡沫细胞中MMP-9蛋白表达的影响,通过迁移实验观察特异性抑制EMMPRIN表达对单核细胞迁移能力的影响。结果:采用EMMPRIN-siRNA转染巨噬、泡沫细胞,抑制细胞内EMMPRIN的基因和蛋白表达(P0.01)后使巨噬、泡沫细胞中MMP-9的蛋白表达减少了50%和40%。此外特异性抑制EMMPRIN表达使单核细胞在趋化因子MCP-1、VEGF趋化诱导下迁移能力明显减弱(P0.05)。结论:EMMPRIN基因沉默使巨噬、泡沫细胞中MMP-9的蛋白表达明显减少、活性明显减弱同时使单核细胞的趋化迁移能力降低。由此可见EMMPRIN在MMP的表达、活化及单核细胞迁移中扮演重要角色,可能成为防治动脉粥样硬化新的治疗靶点。     

Matrix metalloproteinase 9 (gelatinase B) is expressed in multinucleated giant cells of human giant cell tumor of bone and is associated with vascular invasion.

Human giant cell tumor (GCT) consists of multinucleated giant cells and mononuclear stromal cells, and is characterized by frequent vascular invasion without distant metastases. To study the role of matrix metalloproteinases (MMPs) in the vascular invasion, we examined production of MMP-1 (tissue collagenase), -2 (gelatinase A), -3 (stromelysin-1), -9 (gelatinase B), and tissue inhibitors of metalloproteinases (TIMP-1 and -2) in GCT. MMP-9 was highly and predominantly expressed in giant cells by both immunohistochemistry and in situ hybridization. Expression of other MMPs was also observed in some cases but was inconstant. Sandwich enzyme immunoassays demonstrated that MMP-9 is the predominant MMP secreted by GCT. There was a definite imbalance between the amounts of MMP-9 and those of TIMPs in the culture media of GCT, leading to detectable gelatinolytic activity in an assay using 14C-gelatin. Gelatin zymography demonstrated the main activity at about 90 kd, which was identified as the zymogen of MMP-9 by immunoblotting. Immunohistochemistry for type IV collagen and laminin, major basement membrane components, showed that disappearance of the proteins is closely associated with MMP-9-positive giant cells. These results indicate the production of MMP-9 by multinucleated giant cells and suggest that the metalloproteinase may contribute to proteolysis associated with vascular invasion and local bone resorption in human GCT.     

Role of DDR1 in the gelatinases secretion induced by native type IV collagen in MDA-MB-231 breast cancer cells

Discoidin domain receptors (DDRs) are receptor tyrosine kinases that get activated by collagens in its native triple-helical form. In mammalian cells, DDR family consists of two members, namely DDR1 and DDR2, which mediates migration and proliferation of several cell types. DDR1 is activated by native type IV collagen and overexpressed in human breast cancer. Type IV collagen is the main component of basement membrane (BM), and the ability to degrade and penetrate BM is related with an increased potential for invasion and metastasis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that collectively are capable of degrading all components of the extracellular matrix, including the BM. In breast cancer cells, denatured type IV collagen induces MMP-9 secretion and invasion. However, the role of DDR1 in the regulation of gelatinases (MMP-2 and -9) secretion and invasion in breast cancer cells remains to be studied. We demonstrate here that native type IV collagen induces MMP-2 and -9 secretions and invasion through a DDR1 and Src-dependent pathway, together with an increase of MMP-2 and -9-cell surface levels. MMP-2 and -9 secretions require PKC kinase activity, epidermal growth factor receptor (EGFR) activation, arachidonic acid (AA) production and AA metabolites in MDA-MB-231 breast cancer cells. In summary, our data demonstrate, for the first time, that DDR1 mediates MMP-2 and -9 secretions and invasion induced by native type IV collagen in MDA-MB-231 breast cancer cells.     

Progesterone receptor modulator CDB-2914 induces extracellular matrix metalloproteinase inducer in cultured human uterine leiomyoma cells

Effects of progesterone receptor modulator CDB-2914 on the expression of the extracellular matrix (ECM) components were examined in cultured human uterine leiomyoma and myometrial cells. ECM metalloproteinase inducer (EMMPRIN), matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMPs) and collagen levels were assessed by Western blot analysis, MMP activity assay and real-time RT-PCR. RNA interference (RNAi) of EMMPRIN was performed using small interfering mRNA. In cultured leiomyoma cells, CDB-2914 treatment at concentrations greater than or equal to 10(-8) M significantly increased EMMPRIN, MMP-1 and MMP-8 protein contents and MMP-1, MMP-2, MMP-3 and MMP-9 mRNA levels, and activity of MMP-1, MMP-2, MMP-3 and MMP-9 in the medium. TIMP-1 and TIMP-2 were significantly decreased at mRNA and protein levels by CDB-2914 treatment at concentrations > or =10(-7) M in these cells. CDB-2914 treatment decreased types I and III collagen protein contents. However, CDB-2914 treatment did not affect the ECM component expression in cultured myometrial cells. RNAi of EMMPRIN abrogated CDB-2914-mediated both induction of MMPs and reduction of TIMPs and collagens in cultured leiomyoma cells. These results suggest that CDB-2914 modulates the expression of EMMPRIN, MMPs, TIMPs and collagens in cultured leiomyoma cells without comparable effects on myometrial cells.     

Extracellular matrix metalloproteinase inducer in interstitial pneumonias

Extracellular matrix metalloproteinase inducer (EMMPRIN), a glycosylated transmembrane protein that induces matrix metalloproteinases (MMPs), is minimally expressed in the normal adult lung. We previously reported that it is up-regulated in murine bleomycin-induced lung injury. In this study, we determined the expression of EMMPRIN and its association with MMP-2, MMP-7, and MMP-9 in interstitial pneumonias (IPs). We performed immunohistochemistry for EMMPRIN and MMPs on lung tissue from 22 subjects with various IPs. We did bronchoalveolar lavage (BAL) on 9 of these subjects and 13 others with IPs to measure the soluble EMMPRIN in BAL fluid. For comparison, immunohistochemistry or BAL was done on 14 subjects without IPs. The staining intensity for each protein was scored from 0 to 3 in various epithelial cell types. Soluble EMMPRIN in BAL fluid was measured by an enzyme-linked immunosorbent assay. Extracellular matrix metalloproteinase inducer was prominent in abnormal epithelial cells. It was more prominent in hyperplastic type II cells, compared with epithelium in alveolar bronchiolization. It was also elevated in BAL fluid from the subjects with IPs. Matrix metalloproteinases were expressed in cells expressing EMMPRIN, although the profile of MMPs varied among the different abnormal epithelial cell types with MMP-2 and MMP-7 in hyperplastic type II cells and MMP-7 and MMP-9 in cells showing squamous metaplasia and cells comprising bronchiolization. These results suggest a role of EMMPRIN in reepithelialization in IPs.     

Overexpression of MMP-9 contributes to invasiveness of prostate cancer cell line LNCaP

Matrix metallaprotinase-9 (MMP-9) is zinc-containing proteinase whose expression and trafficking are frequently altered in cancer. MMP-9 in the plasma membrane and the secreted forms are thought to contribute to the invasive and metastatic properties of malignant tumors. We have manipulated the expression of MMP-9 in prostate tumor cell line LNCaP and measured their capacity to invade through a basement membrane matrix. Stable expression of human MMP-9 in a poorly metastatic LNCaP prostate cancer cell line produced a 2-3-fold increase in MMP-9 activity and a comparable increase in invasiveness. Transient transfection of LNCaP stable clone expressing MMP-9 with MMP-9 antisense oligonucleotide (ASODN) produced 55-90% less MMP-9 than control cells and were proportionately less invasive. In contrast, manipulating MMP-9 levels had no effect on cell migration across an uncoated membrane. A standard MMP-9 inhibitor at a concentration ranging from 1-10 nM, caused a nearly quantitative inhibition of extracellular MMP-9 activity and had significant effect on basement membrane invasion. Collectively, these results confirm the role of MMP-9 in tissue remodeling associated with prostate tumor invasion.     

Melanoma invasion in reconstructed human skin is influenced by skin cells – investigation of the role of proteolytic enzymes

Melanoma invasion is a complex multi stage process involving changes to the cell/extracellular matrix (ECM) and cell/cell interactions. We have previously shown using an in vitro model of reconstructed human skin (consisting of human dermis with a basement membrane [BM] and populated with human skin cells) that some melanoma cells (HBL cell line) invade more actively in the presence of adjacent normal skin cells. The aim of the present study was to further investigate the relationship between melanoma cells, skin cells and ECM proteins during melanoma cell invasion through reconstructed skin, extending this to a study of three melanoma cell lines. We also examined whether such cell/cell induced invasion is due to increased expression and activation of matrix-metalloproteinase-2 (MMP-2) and MMP-9, or due to increases in general protease activity for keratinocytes, fibroblasts or melanoma lines. Addition of skin cells dramatically altered the invasive behaviour of the three metastatic melanoma cell lines (HBL, C8161 and A375SM) used; they increased the invasive ability of HBLs which were unable to invade on their own; they potentiated the invasion of C8161 cells which were invasive in their own right, but reduced the invasion of A375-SM cells which were aggressive invaders in the absence of skin cells. Latent forms of MMP-2, and MMP-9, were clearly expressed by the normal skin cells whereas all three melanoma lines weakly expressed these proteases. Fibroblast and keratinocyte MMPs were activated specifically by culture on type I collagen and on dermis which retained an intact basement membrane. These findings demonstrate that while there is an active communication between melanoma cells and adjacent skin cells, the invasive process is dictated by the melanoma cells and not the skin cells. However, activation of skin cell derived MMPs may play an important role in facilitating invasion by particular melanoma phenotypes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Human breast cancer cells activate procollagenase-1 and invade type I collagen: invasion is inhibited by all-trans retinoic acid

Matrix metalloproteinases (MMPs) play an important role in tumor cell invasion and metastasis. These processes require the dissolution of the basement membrane and invasion of the stromal matrix (ECM), and are mediated by MMPs. Consequently, MMP inhibitors may be attractive as new anticancer agents. To examine the potential contribution of collagenase-1 (MMP-1) in invasion of stromal matrix, we used the highly invasive and metastatic breast cancer cell line MDA-MB-231 as a model system. These cells express procollagenase-1 constitutively and this expression can be repressed by all-trans retinoic acid. Invasion of these cells into a collagen type I matrix was assessed by scanning electron microscopy (SEM), and was quantitated with a computer program and confocal laser scanning microscopy (CLSM). We found that MDA-MB-231 cells freely invaded the collagen type 1 matrix, suggesting that these cells possess a mechanism for activating the latent collagenase-1. In contrast, down-regulation of collagenase-1 expression by all-trans retinoic acid caused these cells to become less invasive. To confirm a role for collagenase-1 in mediating collagen type I invasion, assays were carried out in the presence of FN-439, an inhibitor of collagenase-1 enzyme activity. We found that in the presence of the proteinase inhibitor, invasion of type I collagen by MDA-MB-231 cells was also reduced. These results indicate that collagenase-1 produced by the breast tumor cells may enhance stromal matrix degradation by enabling the tumor cells to modulate their own invasive behavior, and suggest that decreasing collagenase-1 levels may be effective in breast cancer therapy.     

A novel 3-dimensional culture system as an in vitro model for studying oral cancer cell invasion

Tissue microenvironment plays a critical role in tumour growth and invasion. This study established a novel 3-dimensional (3-D) cell invasion model for direct microscopic observation of oral cancer cell invasion into the underlying basement membrane and connective tissue stroma. A multilayer cell construct was developed using the OptiCell chamber, consisting of a lower layer of oral mucosa fibroblasts embedded in collagen gel and an overlaying upper layer of oral cancer cells. The two layers are separated by a basement membrane composed of reconstituted extracellular matrix. To verify the applicability of the cell invasion model, multilayer cell constructs of oral squamous cell carcinoma and oral mucosal fibroblasts were exposed to extrinsic urokinase-type plasminogen activator (uPA) or plasminogen activator inhibitor (PAI-1), which are known effectors of cell migration. In addition, the constructs were exposed to both normoxic and hypoxic culture conditions. Microscopic study showed that the presence of uPA enhanced cell invasion, while PAI-1 inhibited cell migration. Western blot and zymographic analysis demonstrated that hypoxia up-regulated uPA and matrix metalloproteinases (MMPs) expression and activity; conversely, PAI-1 level was down-regulated in response to hypoxic challenge as compared to normoxic condition. Our results indicated that the novel 3-D invasion model could serve as an excellent in vitro model to study cancer cell invasion and to test conditions or mediators of cellular migration.     

Implication of extracellular matrix metalloproteinases in the course of chronic inflammatory airway diseases

Matrix metalloproteinases (MMPs) are major proteolytic enzymes that are involved in extracellular matrix (ECM) turn over. MMP-2 (gelatinase A) and MMP-9 (gelatinase B) cleave type IV collagen, which is an important constituent of basement membrane. These enzymes play an important role in normal tissue homeostasis, but imbalance between MMPs and their tissue inhibitors (TIMPs) is thought to be a critical factor in regulating tissue remodeling. MMP-2 is produced by fibroblasts, endothelial, and epithelial cells, while MMP-9 is mainly produced by inflammatory cells. The role of MMPs was investigated through biochemical analysis or in situ expression, in the pathogenesis of two chronic inflammatory airway diseases, asthma and nasal polyposis. Both are characterized with the accumulation of active inflammatory cells, matrix remodeling and epithelial changes. Increased levels of MMP-9 and TIMP-1 were found in asthmatic subjects and NP. In NP, MMP-9 expression was detected in epithelial, endothelial and inflammatory cells. In this setting, MMP-9 could play a crucial role in the transmigration of basement membrane components by inflammatory cells leading to inflammatory cell accumulation and maintenance of inflammation in airway. Moreover, MMP-9 may contribute to cell migration, an important mechanism involved in the repair of the respiratory epithelium.     

Ovarian cancer cell invasion is inhibited by paclitaxel

Overproduction of matrix metalloproteinases (MMPs) and alterations in adhesive and migratory behavior are common characteristics of metastatic cancer cells. Ovarian cancer is a highly invasive type of malignancy. The effect of the antineoplastic drug paclitaxel on human ovarian cancer cell (Ovcar-3) invasion was studied using an in vitro invasion assay with reconstituted basement membrane. The effect of treatment with paclitaxel was also determined separately on certain invasion-associated events, such as the secretion of 72 kDa type IV collagenase (gelatinase A/MMP-2), the expression of the tissue inhibitor of metalloproteinase-2 (TIMP-2), cell attachment and migration. Ovcar-3 cell attachment, migration and in vitro invasion were significantly decreased after paclitaxel treatment (P=0.02, P<0.01 and P=0.001, respectively) whereas no alteration in the secretion of latent MMP-2 was noted. However, the intracellular localization of the immunoreactive protein for MMP-2 was altered in response to paclitaxel treatment. Interestingly, paclitaxel increased the appearance of TIMP-2 protein in culture medium (P=0.002) but did not change the expression of mRNA for TIMP-2 in Ovcar-3 cells. These data show that paclitaxel is an effective suppressor of Ovcar-3 cell invasion. It inhibits attachment and migratory activities of the cells but also causes a release of TIMP-2 protein into the tissue culture medium.     

基质金属蛋白酶及其组织抑制因子在人前列腺组织及各种类型前列腺细胞中的表达

目的：研究基质金属蛋白酶（MMPs）及其组织抑制因子（TIMPs）在人前列腺组织及各种类型细胞中的表达。方法： 用半定量RT－PCR的方法，对癌变和非癌变部分的前列腺组织、原代培养的平滑肌细胞、成纤维细胞、上皮细胞以及4种前列腺上皮细胞系（BPH－1、LNCaP、DU－145和PC－3）中MMP2、MMP7和MMP9、膜型基质金属蛋白酶1和3（MT1－MMP和MT3－MMP）及其组织抑制因子1和2（TIMP－1和TIMP－2）的mRNA 水平进行了测定。结果：MMP-2主要在前列腺基质细胞中表达；MMP-7和MMP-9则在前列腺上皮细胞中有较高的表达；MT1-MMP、MT3-MMP、TIMP-1和TIMP-2在前列腺基质细胞和上皮细胞中均有表达，但MT1-MMP和MT3-MMP在成纤维细胞中的表达量较高；另外，各种基质金属蛋白酶及其组织抑制因子在各种前列腺细胞系中也存在差异表达。结论： MMPs和TIMPs在前列腺组织及其各种类型细胞中的差异表达提示：它们可能在前列腺癌的转移中起着不同的作用。