Differential expression of matrilysin-1 (MMP-7), 92 kD gelatinase (MMP-9), and metalloelastase (MMP-12) in oral verrucous and squamous cell cancer

Squamous cell carcinoma (SCC) of the oral cavity is a highly invasive tumour of stratified squamous epithelium that spreads through degradation of the basement membrane (BM) and extracellular matrix (ECM). There are currently no reliable tissue or serum markers to predict whether the tumour has metastasized at the time of diagnosis. Verrucous carcinoma (VC) of the oral cavity is a rare low-grade variant of oral SCC that penetrates into the subepithelial connective tissue. Many matrix metalloproteinases (MMPs), such as MMP-1, -2, -7, -9, -13, and -14, as well as integrin receptors have been implicated in cancer invasion. Integrin alphavbeta6 is induced in SCC and appears to be involved in up-regulation of MMP-9 expression by oral keratinocytes and promotion of their migration. The aim of this study was to investigate whether the pattern of MMP expression or that of alphavbeta6 integrin contributes to the differences in the biological behaviour of oral SCC and VC. The results show that the less aggressive nature of oral VC may be connected to its MMP expression profile. Typically, VCs were devoid of epithelial MMP-3, -7, -9, -12 and -13 expression, compared with SCCs. MMP-19 was expressed by epithelial keratinocytes in hyperproliferative areas of verrucous hyperplasia, VC, and SCC, but was absent in the invasive cancer cell nests of SCC. MMP-26 was expressed by hyperproliferative keratinocytes in VC as well as by invasive cancer cells in SCCs. MMP-10 was expressed widely in the epithelium of all SCC specimens. alphavbeta6 integrin expression was also detected in some cases of epithelial hyperplasia but was significantly more abundant in cancers at the invasive front. The absence of MMP-7, -9 and -12 from epithelial cells may serve as a good prognostic marker of non-invasive oral carcinoma. Blocking the activity of invasion-specific MMPs or alphavbeta6 integrin might offer novel therapeutic modalities in early-stage oral carcinoma.     

The clinicopathological and prognostic significance of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP-9 according to their localization in invasive breast carcinoma

AIMS: To investigate the clinicopathological and prognostic significance of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP-9 proteins expression in invasive breast carcinoma and their relationship to tumour proliferation and expression of c-erbB2 and peroxisome proliferator-activated receptor (PPAR) gamma. METHODS: Immunohistochemistry was carried out on 175 paraffin-embedded breast tissue specimens to detect MT1-MMP, MMP-9, oestrogen receptor (ER), progesterone receptor, c-erbB-2, Ki67, topoisomerase IIalpha (topo IIalpha) and PPARgamma protein expression. RESULTS: Both MT1-MMP and MMP-9 were expressed in the cytoplasm of the malignant cells and the peritumoral stroma. Cytoplasmic MT1-MMP was more often observed in ER+ tumours (P = 0.022), of a lower nuclear grade (P = 0.020) and with reduced expression of Ki67 and topo IIalpha (P = 0.027 and P = 0.006, respectively). Moreover, cytoplasmic MT1-MMP was positively associated with MMP-9 (P = 0.010) and PPARgamma (P < 0.0001). Cytoplasmic MMP-9 was inversely associated with Ki67 (P = 0.034) and topo IIalpha (P = 0.004), whereas its relationship with MT1-MMP (P = 0.034) and PPARgamma (P = 0.024) was found to be positive. Stromal MMP-9 was more often observed in c-erbB2+ tumours (P = 0.043) and had an unfavourable impact on overall and relapse-free survival in both univariate (P = 0.0157 and P = 0.0274, respectively) and multivariate analyses (P = 0.007 and P = 0.024, respectively). CONCLUSIONS: Cytoplasmic MT1-MMP and MMP-9 seem to be related to well-differentiated tumours, with a low proliferation potential, while stromal MMP-9 is associated with an aggressive tumour phenotype and is recognized as an independent poor prognostic indicator.     

Morphological changes of cerebral vessels and expression patterns of MMP-2 and MMP-9 on cerebrovascular wall of alcoholic rats

Alcohol abuse increases the incidence of cerebral accidents, which correlates with cerebrovascular structural changes. The present study was designed to observe the cerebrovascular remodeling of drinking rats with light microscopy and transmission electron microscopy (TEM). Short-term alcohol administration induced apparent amplification of perivascular spaces around small vessels in brain tissue, while long-term administration caused pathological changes of basilar arteries (BAs), including endothelial exfoliation, inner elastic lamina (IEL) fragmentation and thickening of tunica media and adventitia. In addition, the relationship between cerebrovascular remodeling and MMP-2 and MMP-9 synthesized by endothelial cells and vascular smooth muscle cells was explored by immunohistochemistry. The two protein expression in cerebral vessels changed dynamically, peaking at 1-2 weeks after treatment, and decreasing as treatment continued. These results suggest that MMP-2 and MMP-9 may play a significant role in blood-brain barrier disruption after alcohol abuse. But the chronic changes of cerebral arteries resulted from drinking are not coincident with time course of MMP-2 and MMP-9 expression in situ.     

Expression and Roles of MMP-2, MMP-9, MMP-13, TIMP-1, and TIMP-2 in Allergic Nasal Mucosa

Purpose

Allergic rhinitis (AR) and asthma share many characteristics, but structural changes are observed far less often in AR. Matrix metalloproteinases (MMPs) constitute a family of Zn-dependent endopeptidases that can decompose the extracellular matrix and basement membrane, and regulate cell infiltration. We analyzed the expression of MMPs and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs), in allergic nasal mucosa after nasal allergen challenge (NAC) and determined their relationship to inflammatory cells.

Methods

Nasal mucosa specimens were obtained at surgery performed for hypertrophied turbinates. We performed NAC with house dust mite (HDM) allergen disks and control disks, and took biopsies at 30 minutes, 6 hours, and 12 hours after NAC. Cells expressing MMP-2, MMP-9, MMP-13, TIMP-1, and TIMP-2, as well as eosinophils and mast cells, were analyzed immunohistochemically. The MMPs and TIMPs in allergic nasal mucosa were quantified using enzyme-linked immunosorbent assays.

Results

At 30 minutes post-NAC, HDM-exposed nasal mucosa exhibited significantly more MMP-2+, MMP-9+, MMP-13+, TIMP-1+, and TIMP-2+ cells compared with control mucosa, and the numbers of MMP-9+ and TIMP-1+ cells correlated strongly with the number of mast cells. At 6 hours post-NAC, the numbers of MMP+ and TIMP+ cells did not differ significantly between HDM-exposed mucosa and control mucosa, but the ratios of MMP+ cells to TIMP+ cells were higher in HDM-exposed mucosa. At 12 hours post-NAC, the number of MMP-13+ cells tended to be higher in HDM-exposed mucosa and was strongly correlated with the number of eosinophils. Quantitatively, the levels of MMP-2 and MMP-13 were significantly higher than the MMP-9 level, and the TIMP-2 level was significantly higher than the TIMP-1 level in allergic nasal mucosa.

Conclusions

We demonstrated increased expression of MMP-2, MMP-9, and MMP-13 in allergic nasal mucosa, high MMPs-to-TIMP-1 ratios, and a strong correlation between MMP-9 and mast cells and between MMP-13 and eosinophils. The imbalance between MMPs and TIMPs may contribute to the migration of inflammatory cells such as eosinophils and mast cells to the nasal mucosa of AR patients, suggesting a possible active role of MMPs in AR.     

Increased MMP-2 activity during intervertebral disc degeneration is correlated to MMP-14 levels

Intervertebral disc (IVD) degeneration is associated with the increased expression of several matrix metalloproteinases (MMPs), in particular MMP-2. However, little is known about the actual activity of MMP-2 in healthy and degenerated discs, or what mechanisms are involved in its activation. A major activation pathway involves complex formation with MMP-14 and a tissue inhibitor of metalloproteinases-2 (TIMP-2). In a series of 56 human IVDs, obtained at autopsy and graded according to the Thompson score (I-V), we analysed whether MMP-2 activity was increased in different stages of IVD degeneration and to what extent activation was related to the production of MMP-14 and TIMP-2. MMP-2 activation and production were quantified by gelatin zymography. Immunohistochemical staining of MMP-14 and TIMP-2 was quantified with a video overlay-based system. A positive correlation was observed between the amount of active MMP-2 and pro-MMP-2 and degeneration grade (p < 0.001, correlation coefficient (CC) 0.557; and p < 0.001, CC 0.556, respectively). MMP-2 activity correlated positively with MMP-14 and less strongly with TIMP-2 (p = 0.001, CC 0.436; and p = 0.03, CC 0.288, respectively). Moreover, immunopositivity for MMP-14 correlated to degeneration grade (p = 0.002, CC 0.398). IVD degeneration was associated with the activity of MMP-2 and the correlation of its activation with MMP-14 production suggests MMP-14 activates MMP-2 during degeneration. As MMP-14 is capable of activating several other enzymes that are also thought to be involved in IVD degeneration, it may be a key mediator of the degenerative process.     

AQP4,MMP-2及MMP-9在高血压性脑出血后脑水肿中的早期表达

目的：探讨水通道蛋白4（AQP4）及基质金属蛋白酶2，9（MMP-2，MMP-9）表达在高血压性脑出血后早期脑水肿发生中的作用。方法：应用免疫组织化学方法检测高血压性脑出血患者出血后24h内血肿周围脑组织中AQP4及MMP-2、MMP-9的表达。结果：高血压性脑出血患者血肿周围有明显的脑动脉硬化和脑水肿发生，正常对照组中未发现明显的MMP-2，MMP-9阳性表达，AOP4可见少量表达，而在高血压性脑出血组出血24h内AQP4，MMP-2及MMP-9则见明显表达（P〈0．01），尤其是AQP4的阳性表达升高更为显著，在小血管及神经胶质细胞中均见大量表达。结论：AQP4、MMP-2及MMP-9的早期上调表达与高血压性脑出血后脑水肿的发生具有密切的关系。尤其是AQP4的表达在早期脑水肿的发生、发展中具有重要的作用。     

The multifunctional role of the immunohistochemical expression of MMP-7 in invasive breast cancer

The secretion of matrix metalloproteinases (MMPs) is crucial in the metastasis of cancer cells, since MMPs are responsible for the degradation of extracellular matrix (ECM). Among them, matrix metalloproteinase-7 (MMP-7) or matrilysin 1 is a stromelysin which degrades type-IV collagen, fibronectin and laminin. Immunohistochemistry was performed to detect MMP-7 protein in infiltrative breast carcinomas. MMP-7 was studied along with clinicopathological parameters, disease-free and overall survival, and p53, c-erbB-2, topoIIa, MMP-2, uPAR and beta-catenin. MMP-7 immunoreactivity was detected in the cytoplasm of cancer cells in 54.2% (96/177) and tumor stromal cells in 47.5% (84/177), as well as in normal epithelium adjacent to malignant epithelium. MMP-7 reactivity in cancer cells displayed an inverse association with nuclear grade (p=0.049) and topoIIa (p=0.03). A parallel association was observed between the expression of MMP-7 in both malignant and stromal cells with uPAR in cancer cells (p=0.033 and p=0.027, respectively). MMP-7 of tumor stromal cells depicted a parallel correlation with MMP-2 of the same cell type (p=0.044), while abnormal beta-catenin expression was inversely associated with MMP-7 of cancer cells (p=0.047). Our results show the multifunctional role of MMP-7 in the mammary gland, since it seems to be associated with a less aggressive phenotype, while, at the same time, being involved in invasion, through its collaboration with indicators of invasion.     

In vivo collagenase-2 (MMP-8) expression by human bronchial epithelial cells and monocytes/macrophages in bronchiectasis

The purpose of this study was to determine whether other cellular sources than neutrophils can express matrix metalloproteinase (MMP)-8 protein and mRNA in bronchiectatic (BE) lung. The molecular forms of MMP-8 in the BE bronchoalveolar lavage fluid (BALF) and healthy control BALF were analysed by western immunoblotting. MMP-8 expression was demonstrated by immunohistochemistry and in situ hybridization in BE lung tissue and by immunohistochemistry in control lung tissue. In the BE BALF, different MMP-8 species were detected: 70-80 kD MMP-8 apparently of polymorphonuclear leukocyte (PMN) origin and also 40-60 kD MMP-8 from non-PMN cellular sources, such as bronchial epithelial cells, glandular cells or monocytes/macrophages. Both of these MMP-8 species were elevated and converted to a significant extent to activated forms in BE BALF compared with healthy control BALF. The levels of high molecular weight (>80 kD) MMP-8 complexes, evidently representing MMP-8 trapped by endogenous MMP inhibitors and/or MMP-8 dimers, were significantly elevated in BE BALF compared with healthy control BALF. In BE lung tissue, the MMP-8 protein and mRNA expression was found in bronchial ciliated epithelial cells, glandular cells, neutrophils, and monocytes/macrophages infiltrating the bronchial epithelial area. Minimal MMP-8 expression was observed in neutrophils, monocytes/macrophages, and epithelial cells in control lung tissues. In this study, new potential cellular sources have been demonstrated for MMP-8 in the inflamed lung. MMP-8 from multiple cellular sources, including inflamed lung epithelium, was activated to a significant extent in the BE BALF, indicating a major role for MMP-8 in the destruction of lung and bronchial tissues.     

前列腺间质细胞中雌二醇对MMP-2，MMP-9及其组织抑制因子表达的影响

目的： 研究雌二醇(E2)对前列腺间质细胞中基质金属蛋白酶(MMP-2、MMP-9）及其组织抑制因子1(TIMP-1)、TIMP-2和雌激素受体α、β（ERα、ERβ）的影响。方法： 实时定量PCR法检测E2在前列腺间质细胞中对MMP-2、MMP-9、TIMP-1、TIMP-2 mRNA水平的影响；半定量RT-PCR法检测E2对ERα、ERβ mRNA水平的影响。酶谱电泳法检测MMP-2、MMP-9的活性。Western blotting检测E2在前列腺间质细胞中对ERα蛋白水平的影响。结果： 前列腺间质细胞中有MMP-2和ERα mRNA的表达，未检测到MMP-9 mRNA；培养液中检测到MMP-2前体（pro-MMP-2），未检测到其活性形式，也未检测到MMP-9前体及其活性形式。用E2处理间质细胞后MMP-2 mRNA水平降低，pro-MMP-2蛋白量减少，雌激素受体抑制剂ICI 182.780可抑制此作用。E2对TIMP-1,2 mRNA表达无显著影响。E2能够增加前列腺间质细胞中ERα mRNA及其蛋白表达的水平。结论： E2能够通过ERα下调前列腺间质细胞中MMP-2的表达。     

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.     

Transcriptional factors for epithelial-mesenchymal transition are associated with mesenchymal differentiation in gliosarcoma

Gliosarcoma is a rare variant of glioblastoma characterized by a biphasic pattern of glial and mesenchymal differentiation. It is unclear whether mesenchymal differentiation in gliosarcomas is because of extensive genomic instability and/or to a mechanism similar to epithelial-mesenchymal transition (EMT). In the present study, we assessed 40 gliosarcomas for immunoreactivity of Slug, Twist, matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), which are involved in EMT in epithelial tumors. Nuclear Slug expression was observed in >50% of neoplastic cells in mesenchymal tumor areas of 33 (83%) gliosarcomas, but not in glial areas (P < 0.0001). Nuclear Twist expression was observed in >50% of neoplastic cells in mesenchymal tumor areas of 35 (88%) gliosarcomas, but glial tumor areas were largely negative except in four cases (P < 0.0001). Expression of MMP-2 and MMP-9 was also significantly more extensive in mesenchymal than in glial tumor areas. None of 20 ordinary glioblastomas showed Slug or Twist expression in >10% neoplastic cells. Thus, expression of Slug, Twist, MMP-2 and MMP-9 was characteristic of mesenchymal tumor areas of gliosarcomas, suggesting that mechanisms involved in the EMT in epithelial neoplasms may play roles in mesenchymal differentiation in gliosarcomas.     

Inverse relationships between the expression of MMP-7 and MMP-11 and predictors of poor prognosis of papillary thyroid carcinoma

AIMS: Matrix metalloproteinases (MMPs) have various functions that play roles in carcinoma development. In this study, we investigated the expression of two representative MMPs, MMP-7 and MMP-11, in papillary thyroid carcinomas. METHODS: We immunohistochemically investigated the expression of these MMPs in 196 cases of papillary carcinoma. RESULTS: A high level of MMP-7 expression was observed in 56 cases (28.3%). The expression level was significantly decreased in cases showing large tumour, N positivity, large pT and poor differentiation. MMP-11 expression was high in 119 cases (60.1%). The expression level was inversely related to tumour size, N factor, pT factor, pN factor, extrathyroid extension, and poor differentiation. CONCLUSIONS: In contrast to other MMPs, MMP-7 and MMP-11 are inversely linked to aggressive characteristics of papillary thyroid carcinoma and their down-regulations may even be a marker of poor prognosis in patients.     

Systemic sclerosis fibroblasts inhibit in vitro angiogenesis by MMP-12-dependent cleavage of the endothelial cell urokinase receptor

Failure of endothelial cells to develop new vessels in response to hypoxia is a distinctive feature of systemic sclerosis (SSc) in the avascular phase. We have previously shown that SSc endothelial cells over-express matrix metalloproteinase-12 (MMP-12), which blocks angiogenesis by cleavage of the endothelial urokinase-type plasminogen activator receptor (uPAR). In the present study, we have investigated whether over-expression of MMP-12 and of angiostatic factors, or hypo-expression of angiogenic factors by SSc fibroblasts, contributes to impaired angiogenesis in SSc. Dermal fibroblasts were isolated from healthy subjects (N-Fb) and patients with diffuse SSc (SSc-Fb). Angiogenesis of target normal human microvascular endothelial cells (H-MVECs) was assayed by Matrigel invasion, cell proliferation, and capillary morphogenesis. uPAR cleavage and MMP-12 activity were evaluated by western blotting. We show that the over-expression of MMP-12 by SSc-Fb determines uPAR cleavage in H-MVECs. Conditioned medium from SSc-Fb impaired H-MVEC proliferation, invasion, and capillary morphogenesis. Anti-MMP-12 antibodies restored such impairment. Altered expression of angiostatic/angiogenic factors, including transforming growth factor beta1, did not account for SSc-Fb-dependent impairment of angiogenesis. The over-expression of MMP-12 by both SSc-Fb and SSc endothelial cells indicates that MMP-12 over-production may have a critical pathogenic role in SSc-associated vascular alterations.     

Prognostic value of MMP-2, -9 and TIMP-1,-2 immunoreactive protein at the invasive front in advanced head and neck squamous cell carcinomas

In head and neck cancer as well as in other carcinomas, tumor expansion and spread to distant sites require the secretion of destructive enzymes that degrade the extracellular matrix. A variety of proteases contribute to matrix destruction. Characteristics of the invasive tumor front may reflect tumor prognosis better than do other parts of the tumor. Therefore, it was the aim of the present study to (i) compare central and peripheral tumor zones for differences in the expression of matrix-metalloproteinases (MMP) -2 and -9 and their naturally occurring inhibitors (tissue inhibitor of matrix-metalloproteinases (TIMP) -1 and -2), (ii) examine the morphological potential of malignancy, and (iii) correlate these findings with clinicopathological parameters. The study population consisted of 106 surgical specimens of advanced head and neck squamous cell carcinomas. The invasive front was graded for malignancy, and immunohistochemical staining with MMP-2, MMP-9, TIMP-1 and TIMP-2 antibodies was performed. Both MMP-2 and MMP-9 were found to be significantly overexpressed at the tumor front. The MMP-2-positive invasive front exhibited diminished overall survival times. In multivariate analysis, MMP-2 expression retained its correlation with overall survival in addition to nodal status and total malignancy score. Expression of TIMP-2 correlated with local tumor invasion. We conclude that the expression of MMP-2 at the invasive front is a marker of poor survival and appears to be associated with early recurrence in initially lymph node-negative patients.     

MMP—2和MMP—9在人脑原发性胶质瘤侵袭中的作用

目的 探讨基质金属蛋白酶MMP－2和MMP－9在原发性人脑胶质瘤侵袭行为中的作用。方法 用免疫组织化学S－P法检测MMP－2和MMP－9在胶质瘤和脑内转移瘤中的表达情况;同时通过测量CT影像上的瘤周水肿范围,并与免疫组织化学表达结果作对照比较。结果 1.45例人脑胶质瘤档本中,MMP－2和MMP－9的瘤细胞阳性率分别为35.5%、62.2%,两者之间差别显著（P＜0.05）;MMP－2、MMP－9在高度恶性胶质瘤标本中阳性率分别为56.5%、91.3%,两者之间亦存在明显差别（P＜0.01）;2.MMP－2的染色强度与胶质瘤侵袭指标－－CT瘤周水肿范围无关（P＞0.05）,而MMP－9的染色强度则与其有关（P＜0.05）;也与高度恶性胶质瘤中的表达率无统计学差别（P＞0.05）。结论 MMP－2、MMP－9在人脑胶质瘤中可以作为恶性表型及侵袭指标之一,亦可体现胶质瘤基质降解表型,但不能作为转移表型。其中,MMP－9在人脑胶质瘤侵袭中可能发挥着更重要的作用。     

Neural MMP-28 expression precedes myelination during development and peripheral nerve repair.

Mammalian matrix metalloproteinase 28 (MMP-28) is expressed in several normal adult tissues, and during cutaneous wound healing. We show that, in frog and mouse embryos, MMP-28 is expressed predominantly throughout the nervous system. Xenopus expression increases during neurulation and remains elevated through early limb development where it is expressed in nerves. In the mouse, neural expression peaks at embryonic day (E) 14 but remains detectable through E17. During frog hindlimb regeneration XMMP-28 is not initially expressed in the regenerating nerves but is detectable before myelination. Following hindlimb denervation, XMMP-28 expression is detectable along regenerating nerves before myelination. In embryonic rat neuron-glial co-cultures, MMP-28 decreases after the initiation of myelination. Incubation of embryonic brain tissue with purified MMP-28 leads to the degradation of multiple myelin proteins. These results suggest that MMP-28 plays an evolutionarily conserved role in neural development and is likely to modulate the axonal-glial extracellular microenvironment.     

Effect of cisplatin and BCNU on MMP-2 levels in human glioblastoma cell lines in vitro

Matrix metalloproteinases (MMPs) play an important role in various physiological and pathological conditions such as tissue remodeling, and cancer cell invasion and metastasis. The aim of this study was to determine the effect of the antitumor compounds cis-dichlorodiammine platinum (ii) (cisplatin) and 1, 3 bis (2-chloroethyl)-1-nitrosourea (BCNU) on 72-kDa type IV collagenase activity (MMP-2) in human gliomas. Human glioblastoma cell lines were treated with cisplatin (25M), and BCNU (50M), and the levels of MMP-2 were estimated in serum-free conditioned medium and in cell extracts at different time intervals. Gelatin zymography revealed increased levels of MMP-2 in serum-free conditioned medium and in cell extracts of untreated glioblastoma cell cultures during a 72-h period. In contrast, MMP-2 levels were significantly decreased in cisplatin-treated cells both in conditioned medium and cell extracts. However, no significant changes of MMP-2 levels were noted in BCNU-treated cells. Quantitative analysis of MMP-2 enzyme activity by densitometry and amount of MMP-2 protein by ELISA showed significantly decreased levels of MMP-2 in cisplatin-treated cells compared to BCNU and untreated glioblastoma cells. The results indicate that decreased levels of MMP-2 might represent an additional mechanism by which cisplatin provides its antineoplastic effects.     

MMP-19: cellular localization of a novel metalloproteinase within normal breast tissue and mammary gland tumours

Matrix metalloproteinases (MMPs) are instrumental in promoting and facilitating the spread of malignant diseases and in the de novo formation of blood vessels. This study has mapped the immunoreactivity of a novel, angiogenesis-related metalloproteinase--MMP-19--in normal breast tissue and in benign and malignant breast lesions and compared this pattern of expression with that of MMP-2. In the normal resting mammary gland, MMP-19 was strongly expressed in the myoepithelial layer of the ductal system; the alveolar and ductal epithelia displayed considerable, but lobule-specific, variations in labelling intensity. MMP-19 was also present within the smooth muscle and endothelial layers of large and medium-sized blood vessels, as well as within capillary walls. In benign lesions, all tumour cells and their surrounding vasculature were uniformly and strongly immunoreactive for MMP-19. Progression towards an invasive phenotype and neoplastic dedifferentiation led to the disappearance of MMP-19 from tumour cells and blood vessels and a concomitant rise in the levels of MMP-2. In vitro experiments conducted with isolated smooth muscle cells cultivated on a solid substratum, or within the interstices of a collagen matrix, indicated that the expression of MMP-19 is influenced by the architecture of the surrounding extracellular matrix.