High levels of stromelysin-3 correlate with poor prognosis in patients with breast carcinoma

The expression of matrix metalloproteinase 2, 9 and 11 in Ethiopian breast cancer patients

INTRODUCTION

Matrix metalloproteinases (MMPs) play a pathophysiological role in cancer initiation and progression. Numerous studies have examined an association between MMP-2, MMP-9, and MMP-11 expression and clinicopathological characteristics of breast cancer (BC); however, no research has been done on the MMP expression levels in BC cases from Ethiopia.

MATERIALS AND METHODS

A total of 58 formalin-fixed paraffin-embedded breast tissue samples encompassing 16 benign breast tumors and 42 BC were collected. The RNA was extracted and quantitative reverse-transcription PCR was performed. GraphPad Prism version 8.0.0 was used for statistical analysis.

RESULTS

The MMP-11 expression levels were significantly higher in breast cancer cases than in benign breast tumors (P = 0.012). Additionally, BC cases with positive lymph nodes and ER-positive receptors had higher MMP-11, MMP-9, and MMP-2 expression than cases with negative lymph nodes and ER-negative, respectively. The MMP-11 and MMP-9 expressions were higher in grade III and luminal A-like tumors than in grade I-II and other subtypes, respectively.

CONCLUSION

The MMP-11 expression was higher in BC than in benign breast tumors. Additionally, MMP-11, MMP-9, and MMP-2 were higher in BC with positive lymph nodes and estrogen receptors. Our findings suggest an important impact of MMPs in BC pathophysiology, particularly MMP-11.

High MMP-11 expression associated with low CD8+ T cells decreases the survival rate in patients with breast cancer

Matrix metalloproteinase-11 (MMP-11) promote cancer invasion and metastasis through degrading the extracellular matrix. Protein degradation by MMP-11 in tumor cells may progressively suppress cancer surveillance activities with blocking immune response in breast cancer. The aim of study is to analyze clinicopathological parameters, molecular interactions and anticancer immune response in patients with MMP-11 expression and to provide candidate target drugs. We investigated the clinicopathologic parameters, specific gene sets, tumor antigenicity, and immunologic relevance according to MMP-11 expression in 226 and 776 breast cancer patients from the Hanyang University Guri Hospital (HUGH) cohort and The Cancer Genome Atlas (TCGA) data, respectively. We analyzed pathway networks and in vitro drug response. High MMP-11 expression was associated with worse survival rate in breast cancer from HUGH cohort and TCGA data (all p < 0.05). In analysis of immunologic gene sets, high MMP-11 expression was related to low immune response such as CD8+T cell, CD4+T cell and B cell. In silico cytometry, there was a decrease of cancer testis antigen and low tumor infiltrating lymphocyte in patient with high MMP-11 expression: activated dendritic cell, CD8+T cell, CD4+ memory T cell, and memory B cell. In pathway networks, MMP-11 was linked to the pathways including low immune response, response to growth hormone and catabolic process. We found that pictilisib and AZ960 effectively inhibited the breast cancer cell lines with high MMP-11 expression. Strategies making use of MMP-11-related hub genes could contribute to better clinical management/research for patients with breast cancer.

Structure, regulatory factors and cancer-related physiological effects of ADAM9

The ADAMs family belongs to the transmembrane protein superfamily of zinc-dependent metalloproteases, which consists of multiple domains. These domains have independent but complementary functions that enable them to participate in multiple biological processes. Among them, ADAM9 can not only participate in the degradation of extracellular matrix as a metalloprotease, but also mediate tumor cell adhesion through its deintegrin domain, which is closely related to tumor invasion and metastasis. It is widely expressed in a variety of tumor cells and can affect the proliferation, invasion and metastasis of related cancer cells. We provide our views on current progress, its increasing importance as a strategic treatment goal, and our vision for the future of ADAM9.

Matrix Metalloproteinase-11 Promotes Early Mouse Mammary Gland Tumor Growth through Metabolic Reprogramming and Increased IGF1/AKT/FoxO1 Signaling Pathway, Enhanced ER Stress and Alteration in Mitochondrial UPR

Matrix metalloproteinase 11 (MMP11) is an extracellular proteolytic enzyme belonging to the matrix metalloproteinase (MMP11) family. These proteases are involved in extracellular matrix (ECM) remodeling and activation of latent factors. MMP11 is a negative regulator of adipose tissue development and controls energy metabolism in vivo. In cancer, MMP11 expression is associated with poorer survival, and preclinical studies in mice showed that MMP11 accelerates tumor growth. How the metabolic role of MMP11 contributes to cancer development is poorly understood. To address this issue, we developed a series of preclinical mouse mammary gland tumor models by genetic engineering. Tumor growth was studied in mice either deficient (Loss of Function-LOF) or overexpressing MMP11 (Gain of Function-GOF) crossed with a transgenic model of breast cancer induced by the polyoma middle T antigen (PyMT) driven by the murine mammary tumor virus promoter (MMTV) (MMTV-PyMT). Both GOF and LOF models support roles for MMP11, favoring early tumor growth by increasing proliferation and reducing apoptosis. Of interest, MMP11 promotes Insulin-like Growth Factor-1 (IGF1)/protein kinase B (AKT)/Forkhead box protein O1 (FoxO1) signaling and is associated with a metabolic switch in the tumor, activation of the endoplasmic reticulum stress response, and an alteration in the mitochondrial unfolded protein response with decreased proteasome activity. In addition, high resonance magic angle spinning (HRMAS) metabolomics analysis of tumors from both models established a metabolic signature that favors tumorigenesis when MMP11 is overexpressed. These data support the idea that MMP11 contributes to an adaptive metabolic response, named metabolic flexibility, promoting cancer growth.

Overexpression of MMP Family Members Functions as Prognostic Biomarker for Breast Cancer Patients: A Systematic Review and Meta-Analysis

Background

Matrix metalloproteinases (MMPs) are regarded to be relevant to the prognosis of breast cancer. Numerous studies have confirmed the association between MMPs and tumor growth, invasion and metastasis in breast cancer. However, their prognostic values for survival in patients with breast cancer remain controversial. Hence, a meta-analysis was performed to clarify a more accurate estimation of the role of MMPs on prognosis of breast cancer patients.

Method

A systemic electronic search was conducted in PubMed, Embase and Web of science databases to identify eligible studies, which were associated with the relationship between MMPs and prognosis of breast cancer. The correlation in random-effect model was evaluated by using the hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

A total of 28 studies covering 4944 patients were included for meta-analysis. A summary hazard ratio (HR) of all studies was calculated, as well as the sub-group HRs. The combined HRs calculated by either univariate or multivariate analysis both suggested that overexpression of MMPs had an unfavorable impact on overall survival (OS) (HR = 1.694, 95%CI: 1.347–2.129, P < 0.001; HR = 1.611, 95%CI: 1.419–1.830, P < 0.001, respectively). And the univariate analysis showed that patients with overexpression of MMPs had worse relapse-free survival (RFS) (HR = 1.969, 95%CI: 1.460–2.655, P < 0.001) in all eligible studies. In the sub-group analyses, HRs of MMP-9 positivity with poor OS were 1.794 (95%CI: 1.330–2.420, P < 0.001) and 1.709 (95%CI: 1.157–2.526, P = 0.007) which were separately evaluated by univariate and multivariate analysis. A small number of articles demonstrated that MMP-2 overexpression was not related with shorter OS (HR = 1.400, 95%CI: 0.610–3.029, P = 0.427). Four studies included in the OS analysis of MMPs expression in serum suggested that positive expression of serum MMPs may be an unfavorable factor (HR = 1.630, 95%CI: 1.065–2.494) for breast cancer patients. No publication bias was observed in the current meta-analysis.

Conclusions

Our findings suggested that MMPs overexpression (especially MMP-9, MMP-2, MMPs overexpression in serum) might indicate a higher risk of poor prognosis in breast cancer. Larger prospective studies are further needed to estimate the prognostic values of MMPs overexpression.

Diagnostic and prognostic role of matrix metalloproteases in cancer

BACKGROUND

Matrix metalloproteases (MMPs) are key players in the progression and metastasis of cancer. MMPs cleave extracellular matrix components and in this way promote tumor growth, invasion and vascularization. MMPs also affect tumor progression by regulating availability and activity of growth factors, inflammatory cytokines and chemokines. Accordingly, several MMPs have been found to serve as prognostic indicators in solid tumors. Usually the increased levels of MMPs in patients' tumor tissue or serum/plasma are associated with poor outcome. Interestingly, recent results show that certain MMPs also serve as tumor suppressors.

OBJECTIVE

This review discusses the latest view on MMPs as diagnostic and prognostic indicators in cancer patients.

METHODS

Studies with clinical samples of 70 or more patients are included in particular. In addition, the possible roles of MMPs in future molecular diagnostics and in the evaluation of therapeutic responses are discussed.

CONCLUSION

MMP-9 in particular has shown prognostic value in various types of tumor, and its measurement in circulation, urine or tumor tissue might help in clinical surveillance of otherwise problematic patient cases. There is upcoming new knowledge on MMPs in therapy response evaluation, in which MMPs might be useful together with CT scans and other clinically more established prognostic factors. Certain MMPs have a dual role in terms of cancer-modulating properties and thus it is essential to evaluate their expression and function in tumor cells and host environment to select validated therapy targets but spare MMP antitargets.

Diagnostic and prognostic relevance of MMP-11 expression in the stromal fibroblast-like cells adjacent to invasive ductal carcinoma of the breast

BACKGROUND

Matrix metalloproteinase 11 (MMP-11) is a matrix degrading enzyme known to be involved in the remodeling of extracellular matrix proteins. This enzyme recently has been reported to play a key role in tumor progression and results in poor clinical outcomes for several different types of tumors.

METHODS

A total of 192 patients diagnosed with invasive ductal carcinoma between 2000 and 2005 were included in this study. MMP-11 expression in tumors and stromal fibroblast-like cells was analyzed by immunohistochemical staining on a tissue microarray. Subsequently, evaluation of the associations between MMP-11 expression and clinicopathological characteristics was performed.

RESULTS

MMP-11 expression of stromal fibroblast-like cells was correlated with prognostic factors, including tumor size, metastasis, histological grade, central tumor fibrosis, p53 expression, and luminal A subtype and was linked to therapeutic markers, such as ER and HER2 (all p < 0.05). There was a significant relationship between worse overall survival and MMP-11 expression in both tumors and stromal fibroblast-like cells (all p < 0.05). In multivariate analysis, MMP-11 expression of stromal fibroblast-like cells was still significantly associated with poor prognosis (p = 0.043).

CONCLUSIONS

MMP-11 expression was significantly related to clinicopathological parameters, which may be essential to the prediction of disease outcome in patients with invasive ductal carcinoma of the breast.

Study of matrix metalloproteinases and their inhibitors in prostate cancer

BACKGROUND

Extracellular matrix metalloproteases (MMPs) have raised an extraordinary interest in cancer research because of their potential role in basal membrane and extracellular matrix degradation, consequently facilitating tumour invasion and metastases development.

METHODS

An immunohistochemical study was performed using tissue arrays and specific antibodies against MMPs 1, 2, 7, 9, 11, 13, 14, and their tissue inhibitors, TIMPs 1, 2 and 3. More than 2600 determinations on cancer specimens from 133 patients with clinically localised prostate carcinoma, 20 patients with prostatic intraepithelial neoplasia and 50 patients with benign prostate hyperplasia and controls, were performed.

RESULTS

When compared with benign pathologies, prostate carcinomas had higher expression of all MMPs and TIMPs. Dendogram shows a first-order division of tumours into two distinct MMPs/TIMPs molecular profiles, one of them with high MMPs/TIMs expression profile (n=70; 52.6%). Tumours with high expression of MMP-11 or -13, or cluster thereof, were significantly associated with higher probability of biochemical recurrence.

CONCLUSION

The expression of MMPs and TIMPs seems to have an important role in the molecular biology of prostate carcinomas, and their expression by tumours may be of clinical interest to used as indicators of tumour aggressiveness.

Tissue-dependent induction of apoptosis by matrix metalloproteinase stromelysin-3 during amphibian metamorphosis

Matrix metalloproteinases (MMPs) are a superfamily of Zn(2+)-dependent proteases that are capable of cleaving the proteinaceous component of the extracellular matrix (ECM). The ECM is a critical medium for cell-cell interactions and can also directly signal cells through cell surface ECM receptors, such as integrins. In addition, many growth factors and signaling molecules are stored in the ECM. Thus, ECM remodeling and/or degradation by MMPs are expected to affect cell fate and behavior during many developmental and pathological processes. Numerous studies have shown that the expression of MMP mRNAs and proteins associates tightly with diverse developmental and pathological processes, such as tumor metastasis and mammary gland involution. In vivo evidence to support the roles of MMPs in these processes has been much harder to get. Here, we will review some of our studies on MMP11, or stromelysin-3, during the thyroid hormone-dependent amphibian metamorphosis, a process that resembles the so-called postembryonic development in mammals (from a few months before to several months after birth in humans when organ growth and maturation take place). Our investigations demonstrate that stromelysin-3 controls apoptosis in different tissues via at least two distinct mechanisms.

Expression and prognostic significance of metalloproteases and their inhibitors in luminal A and basal-like phenotypes of breast carcinoma

To analyze the expression and prognostic value of matrix metalloproteases and their tissue inhibitors in luminal A and basal-like breast carcinomas, an immunohistochemical study was performed on cancer specimens from 93 randomly selected patients with invasive primary ductal tumors of the breast (46 with and 47 without distant metastasis) and with luminal A (n = 48) (ER+, HER2-) or basal-like (HER2-, ER-, PgR-) (n = 45) lesions. Luminal B cases were too few to analyze. Specimens were also studied using tissue microarrays and specific antibodies against matrix metalloproteases 1, 2, 7, 9, 11, 13, and 14 and tissue inhibitors 1, 2, and 3. There were no significant differences in matrix metalloprotease or tissue inhibitor expression in the 2 phenotypes of tumors. In basal-like carcinomas, high scores for matrix metalloproteases 9 and 11 were significantly associated with a high distant metastasis rate. Likewise, data showed associations between matrix metalloprotease/tissue inhibitor expression by either stromal fibroblasts or mononuclear inflammatory cells and distant relapse-free survival in both tumor phenotypes. In addition, in infiltrating luminal A and basal-like tumors, we identified a prometastatic phenotype of mononuclear inflammatory cells, showing a high matrix metalloprotease/tissue inhibitor molecular profile. Expression of matrix metalloproteases and tissue inhibitors is related to the characteristics of breast tumor cells. As prognostic factors in breast carcinomas of both luminal A and basal-like phenotypes, our results point to the importance of the expression of matrix metalloproteases and tissue inhibitors by the stromal cells.

Differential regulation of cell type-specific apoptosis by stromelysin-3: a potential mechanism via the cleavage of the laminin receptor during tail resorption in Xenopus laevis

Matrix metalloproteinases (MMPs) have been extensively studied because of their functional attributes in development and diseases. However, relatively few in vivo functional studies have been reported on the roles of MMPs in postembryonic organ development. Amphibian metamorphosis is a unique model for studying MMP function during vertebrate development because of its dependence on thyroid hormone (T3) and the ability to easily manipulate this process with exogenous T3. The MMP stromelysin-3 (ST3) is induced by T3, and its expression correlates with cell death during metamorphosis. We have previously shown that ST3 is both necessary and sufficient for larval epithelial cell death in the remodeling intestine. To investigate the roles of ST3 in other organs and especially on different cell types, we have analyzed the effect of transgenic overexpression of ST3 in the tail of premetamorphic tadpoles. We report for the first time that ST3 expression, in the absence of T3, caused significant muscle cell death in the tail of premetamorphic transgenic tadpoles. On the other hand, only relatively low levels of epidermal cell death were induced by precocious ST3 expression in the tail, contrasting what takes place during natural and T3-induced metamorphosis when ST3 expression is high. This cell type-specific apoptotic response to ST3 in the tail suggests distinct mechanisms regulating cell death in different tissues. Furthermore, our analyses of laminin receptor, an in vivo substrate of ST3 in the intestine, suggest that laminin receptor cleavage may be an underlying mechanism for the cell type-specific effects of ST3.

Mutational analysis of the cleavage of the cancer-associated laminin receptor by stromelysin-3 reveals the contribution of flanking sequences to site recognition and cleavage efficiency

The matrix metalloproteinase stromelysin-3 (ST3) has long been implicated to play an important role in cell fate determination during normal and pathological processes. Using the thyroid hormone-dependent Xenopus laevis metamorphosis as a model, we have previously shown that ST3 is required for apoptosis during intestinal remodeling and that laminin receptor (LR) is an in vivo substrate of ST3 during this process. ST3 cleaves LR at two distinct sites that are conserved in mammalian LR. Human ST3 and LR are both associated with tumor development and cancer progression and human LR can also be cleaved by ST3, implicating a role of LR cleavage by ST3 in human cancers. Here, we carried out a series of mutational analyses on the two cleavage sites in LR. Our findings revealed that in addition to primary sequence at the cleavage site (positions P3-P3', with the cleavage occurring between P1-P1'), flanking sequences/conformation also influenced the cleavage of LR by ST3. Furthermore, alanine substitution studies led to a surprising finding that surrounding sequence and/or conformation dictated the site of cleavage in LR by ST3. These results thus have important implications in our understanding of substrate recognition and cleavage by ST3 and argue for the importance of studying ST3 cleavage in the context of full-length substrates. Furthermore, the LR cleavage mutants generated here will also be valuable tools for future studies on the role of LR cleavage by ST3 in vertebrate development and cancer progression.

Matrix metalloproteinase expression and outcome in patients with breast cancer: analysis of a published database

Traditionally, matrix metalloproteinases (MMPs) have been implicated in cancer invasion and metastasis. Because of their role in these processes, several MMPs have been investigated for potential prognostic value as well as targets for antimetastatic therapy. In this investigation, we used a publically available database to relate messenger RNA expression levels for 17 different MMPs to tumor characteristics and outcome in patients with breast cancer. Of the MMPs investigated, only MMP-1 was significantly increased in tumors >2 cm in size compared with those <or=2 cm while MMP-1, -9, -12 and -15 were significantly elevated in high-grade compared with low-grade tumors. Only MMP-10 was higher in lymph node-positive compared with lymph node-negative cancers. Using univariate analysis, high expressions of MMP-1, -9, -12, -14 and -15 were associated with poor overall survival. Of these five, only MMP-14 predicted outcome independent of tumor size, tumor grade and lymph node status. None of the MMPs investigated were associated with good outcome. We conclude that only a minority of MMPs, i.e. MMP-1, -9, -12, -14 and -15, are associated with adverse outcome in patients with breast cancer. These MMPs are likely to be involved in mediating breast cancer progression and may thus be good targets for designing specific MMP inhibitors for the treatment of breast cancer.

Overexpression of matrix metalloproteinases and their inhibitors in mononuclear inflammatory cells in breast cancer correlates with metastasis-relapse

An immunohistochemical study was performed using tissue microarrays and specific antibodies against matrix metalloproteinase (MMP)-1, -2, -7, -9, -11, -13 and –14, tissular inhibitors of metalloproteinase (TIMP)-1, -2 and -3. More than 2600 determinations on cancer specimens from 131 patients with primary ductal invasive tumours of the breast were performed. To identify specific groups of tumours with distinct expression profiles the data were analysed by unsupervised hierarchical cluster analysis by each cellular type. We did not find well-defined cluster of cases for tumour cells or fibroblastic cells. However, for mononuclear inflammatory cells the dendogram shows a first-order division of the tumours into two distinct MMP/TIMP molecular profiles, designated group 1 (n=89) and group 2 (n=42). Matrix metalloproteinase-7, -9, -11, -13 and -14, and TIMP-1 and -2, were identified as showing significant high expression in group 2 compared with group 1. Multivariate analysis demonstrated that clustering for mononuclear inflammatory cells was the most potent independent factor associated with distant relapse-free survival (group 2: 5.6 (3.5–9.6), P<0.001). We identify a phenotype of mononuclear inflammatory cells infiltrating tumours, which is associated with the development of distant metastasis. Therefore, this finding suggests that these host inflammatory cells could be a possible target for inhibition of metastasis.

Regulation of extracellular matrix remodeling and cell fate determination by matrix metalloproteinase stromelysin-3 during thyroid hormone-dependent post-embryonic development

Interactions between cells and extracellular matrix (ECM), in particular the basement membrane (BM), are fundamentally important for the regulation of a wide variety of physiological and pathological processes. Matrix metalloproteinases (MMP) play critical roles in ECM remodeling and/or regulation of cell-ECM interactions because of their ability to cleave protein components of the ECM. Of particular interest among MMP is stromelysin-3 (ST3), which was first isolated from a human breast cancer and also shown to be correlated with apoptosis during development and invasion of tumor cells in mammals. We have been using intestinal remodeling during thyroid hormone (TH)-dependent amphibian metamorphosis as a model to study the role of ST3 during post-embryonic tissue remodeling and organ development in vertebrates. This process involves complete degeneration of the tadpole or larval epithelium through apoptosis and de novo development of the adult epithelium. Here, we will first summarize expression studies by us and others showing a tight spatial and temporal correlation of the expression of ST3 mRNA and protein with larval cell death and adult tissue development. We will then review in vitro and in vivo data supporting a critical role of ST3 in TH-induced larval epithelial cell death and ECM remodeling. We will further discuss the potential mechanisms of ST3 function during metamorphosis and its broader implications.

Study of matrix metalloproteinases and their inhibitors in breast cancer

An immunohistochemical study was performed using tissue microarrays and specific antibodies against matrix metalloproteinases (MMPs) 1, 2, 7, 9, 11, 13, 14, and their tisullar inhibitors (TIMPs) 1, 2, and 3. More than 2600 determinations on cancer specimens from 131 patients with primary ductal invasive tumours of the breast (65 with and 66 without distant metastasis) and controls were performed. Staining results were categorised using a score based on the intensity of the staining and a specific software program calculated the percentage of immunostained cells automatically. We observed a broad variation of the total immunostaining scores and the cell type expressing each protein. There were multiple and significant associations between the expression of the different MMPs and TIMPs evaluated and some parameters indicative of tumour aggressiveness, such as large tumour size, advanced tumour grade, high Nottinham prognostic index, negative oestrogen receptor status, peritumoural inflammation, desmoplastic reaction, and infiltrating tumoural edge. Likewise, the detection of elevated immunohistochemical scores for MMP-9, 11, TIMP-1, and TIMP-2, was significantly associated with a higher rate of distant metastases. The expression of MMP-9 or TIMP-2 by tumour cells, MMP-1, 7, 9, 11, 13, or TIMP-3 by fibroblastic cells, and MMP-7, 9, 11, 13, 14, TIMP-1, or TIMP-2 by mononuclear inflammatory cells, was also significantly associated with a higher rate of distant metastases.

The collagenase-1 (MMP-1) gene promoter polymorphism - 1607/2G is associated with favourable prognosis in patients with colorectal cancer

Matrix metalloproteinase (MMP) overexpression has been implicated in the pathogenesis of colorectal carcinoma (CRC). Accumulating evidence suggests that MMP promoter single nucleotide polymorphisms (SNPs) effecting gene transcription are associated with enhanced susceptibility for the development of malignant disease, increased tumour invasiveness and poor patient survival. The aim of the current investigation was to determine whether such associations exist in a large CRC patient/control study population. Using an allelic discrimination real-time polymerase chain reaction, polymorphisms in the MMP-1, MMP-2 and MMP-3 gene promoters (−1607, −1306, and −1612 bp, respectively) were assessed in normal blood mononuclear cells from patients with CRC (n=503) and control subjects (n=471). Genotypes corresponding to each MMP SNP were correlated with tumour characteristics and clinical outcome. The frequency of each genotype was not statistically different between patients and control subjects and no significant differences were noted between the genotypes and tumour characteristics for the three MMP SNPs. CRC patients with the 2G/2G genotype for the MMP-1 SNP had significantly better 5-year survival compared to patients with a 1G allele (P<0.05). Our results demonstrate that CRC patients with a 2G/2G genotype in the MMP-1 gene promoter SNP have a favourable prognosis. Although our results were unexpected, given that this genotype is associated with enhanced MMP-1 transcriptional activity, they are consistent with recent data highlighting the anti-tumorigenic properties of MMPs.

Association of 12 serum biochemical markers of angiogenesis, tumour invasion and bone turnover with bone metastases from breast cancer: a crossectional and longitudinal evaluation

Complex biological pathways including angiogenesis, invasion, osteoclastic activation and bone matrix degradation are involved in the formation of bone metastasis (BM). The aim of our study was to investigate the cross-sectional and longitudinal associations of a panel of 12 serum biochemical markers reflecting biological pathways underlying BM development. In a cross-sectional study, we investigated 29 patients with primary breast carcinoma without BM (BC/BM-), 28 patients with breast carcinoma and BM (BC/BM+) and 15 healthy women. In longitudinal analyses, we investigated 34 patients for whom serum was obtained a two different time points: at the time of primary BC diagnosis and after a median time of 3 years. During this follow-up, 15 patients developed BM, whereas the other 19 remained free of BM. In patients who developed BM, the second samples were obtained before BM was documented by bone scan. The cross-sectional analyses have shown all biochemical markers to be significantly elevated in patients with BM, when compared to the patients without BM and healthy controls, except TGFbeta1 that was significantly decreased. Multivariable analyses showed that only the bone resorption markers TRACP 5b, CTX and ICTP, and the marker of angiogenesis VEGF were independently associated with BM. Those markers correctly distinguished 85% of BC patients with or without BM from normal individuals. Longitudinal analyses showed that patients with primary BC who developed BM during follow-up had higher levels of TRACP5b (+95%, P=0.08) at the time of primary diagnosis, those patients had also a higher increases of ICTP (P=0.006), MMP-7 (P=0.004) and TIMP-1 (P=0.017) during follow-up than patients who did not progress toward bone metastasis. This study provides evidence of increase and interrelationship of circulating markers of angiogenesis, invasion and bone resorption in patients with BC with and without BM. Markers of bone resorption have the highest independent diagnostic value for detecting and potentially predicting BM in breast carcinoma patients.

Small integrin binding ligand N-linked glycoprotein gene family expression in different cancers

PURPOSE

Members of the small integrin binding ligand N-linked glycoprotein (SIBLING) gene family have the capacity to bind and modulate the activity of matrix metalloproteinases (MMPs). The expression levels of five SIBLING gene family members [bone sialoprotein (BSP), osteopontin (OPN), dentin matrix protein 1 (DMP1), matrix extracellular phosphoglycoprotein (MEPE), and dentin sialophosphoprotein (DSPP)] and certain MMPs were determined using a commercial cancer array.

EXPERIMENTAL DESIGN

Cancer profiling arrays containing normalized cDNA from both tumor and corresponding normal tissues from 241 individual patients were used to screen for SIBLING and MMP expression in nine distinct cancer types.

RESULTS

Significantly elevated expression levels were observed for BSP in cancer of the breast, colon, stomach, rectum, thyroid, and kidney; OPN in cancer of the breast, uterus, colon, ovary, lung, rectum, and thyroid; DMP1 in cancer of the breast, uterus, colon, and lung; and dentin sialophosphoprotein in breast and lung cancer. The degree of correlation between a SIBLING and its partner MMP was found to be significant within a given cancer type (e.g., BSP and MMP-2 in colon cancer, OPN and MMP-3 in ovarian cancer; DMP1 and MMP-9 in lung cancer). The expression levels of SIBLINGs were distinct within subtypes of cancer (e.g., breast ductal tumors compared with lobular tumors). In general, SIBLING expression increased with cancer stage for breast, colon, lung, and rectal cancer.

CONCLUSIONS

These results suggest SIBLINGs as potential markers of early disease progression in a number of different cancer types, some of which currently lack vigorous clinical markers.

From a unique cell to metastasis is a long way to go: clues to stromelysin-3 participation

Stromelysin-3 (ST3) overexpression is associated with poor patient clinical outcome in numerous carcinomas. The ST3 is expressed by peritumoral fibroblast-like cells. Review of the literature shows that ST3 is an active partner of cancer cells along the whole natural cancer history, and is essential for optimal tumor development as it reduces death of cancer cells invading adjacent connective tissues at the primary tumor site. Paradoxically, ST3 lowers metastasis development in vivo in mice. However, this beneficial effect does not counterbalance the deleterious anti-apoptotic function of ST3.

Legumain expression in relation to clinicopathologic and biological variables in colorectal cancer

PURPOSE

Legumain, a novel asparaginyl endopeptidase, has been observed to be highly expressed in several types of tumors including colorectal cancer. However, there is no study examining the relationship of legumain expression to clinocopathologic and biological variables in colorectal cancers.

EXPERIMENTAL DESIGN

We investigated legumain expression in 164 primary colorectal cancers, 34 corresponding distant normal mucosa samples, 89 adjacent normal mucosa samples, and 33 lymph node metastases using immunohistochemistry. We also did Western blotting analysis on three additional colorectal cancers and three colonic cell lines.

RESULTS

Legumain expression was increased in primary tumors compared with distant or adjacent normal mucosa (P < 0.05), but there was no significant change between primary tumors and metastases (P > 0.05). Legumain expression was positively related to poorer differentiation/mucinous carcinoma (P = 0.04), higher degree of necrosis (P = 0.03) and apoptosis (P < 0.0001), positive proliferating cell nuclear antigen (P < 0.0001) and p53 expression (P = 0.049), and had a positive tendency towards stromelysin 3 (P = 0.058) and PINCH positivity (P = 0.05). The patients with tumors that showed both weak and lower percentage of the legumain expression, either in tumor (P = 0.01) or in stroma (P = 0.04), had a better prognosis.

CONCLUSIONS

The legumain expression may be involved in colorectal cancer development and have a prognostic value in the patients.

Stromelysin 3, Ets-1, and vascular endothelial growth factor expression in oral precancerous and cancerous lesions: correlation with microvessel density, progression, and prognosis

PURPOSE

Identification of molecular changes characteristic of development and progression of oral cancer are of paramount importance for effective intervention. Stromelysin 3 (MMP11) is a unique matrix metalloproteinase shown to have dual function during cancer progression. The transcription factor Ets-1 and vascular endothelial growth factor (VEGF) are important proangiogenic factors in cancer. This study was designed to test the hypothesis that concomitant expression of stromelysin 3, Ets-1, and/or VEGF affects the development, progression, and prognosis of oral cancer.

PATIENTS AND METHODS

Immunohistochemical analysis of stromelysin 3, Ets-1, VEGF, and platelet/endothelial cell adhesion molecule 1 (a marker for intratumoral microvessel density) was carried out in serial paraffin embedded tissue sections of 220 oral squamous cell carcinomas (OSCC), 90 precancerous lesions (59 hyperplasias and 31 dysplasias), and 81 matched histologically normal oral tissues.

RESULTS

Ets-1, VEGF, and stromelysin 3 expression independently correlated with increased intratumoral microvessel density in precancerous lesions (P = 0.05, 0.001, and 0.026, respectively) as well as in SCCs (P = 0.005, 0.01, and 0.031, respectively). Logistic regression analysis revealed that concomitant expression of stromelysin 3 and Ets-1 (stromelysin 3(+)/ Ets-1(+) phenotype; odds ratio, 3.7; P = 0.001) was the most significant predictor for transition to precancerous stage, whereas dual expression of stromelysin 3 and VEGF (stromelysin 3(+)/ VEGF(+) phenotype; odds ratio, 2.07; P = 0.004) was the most important predictor for progression from precancerous stage to frank malignancy. Intriguingly, Ets-1 expression was significantly associated with VEGF expression and stromelysin 3 expression in precancerous tissues as well as OSCCs. Follow-up data for 144 patients for a maximum period of 115 months showed that VEGF [hazards ratio (HR), 4.532; P = 0.004] and Ets-1 (HR = 2.182; P = 0.049) expression significantly correlated with reduced disease-free survival in univariate analysis. In bivariate analysis, patients harboring Ets-1(+)/VEGF(+) phenotype had the worst survival (median disease-free survival, 50 months; HR, 2.943; P = 0.003). Multivariate analysis using Cox's proportional hazards model showed that increased VEGF expression was the most significant adverse prognosticator in OSCC patients (HR, 4.470; P = 0.004).

CONCLUSIONS

In conclusion, this study provides the first evidence of concomitant expression of stromelysin 3, VEGF, and Ets-1 in clinical specimens in different stages of development of oral cancer. In early stages, concomitant expression of stromelysin 3 and Ets-1 favors the development of a precancerous state, whereas dual expression of stromelysin 3 and VEGF is associated with progression from precancerous to cancerous state. VEGF expression is an adverse prognosticator for disease-free survival.

Measurement of the Uncomplexed Fraction of Tissue Inhibitor of Metalloproteinases-1 in the Prognostic Evaluation of Primary Breast Cancer Patients*

Several studies have demonstrated an association between high tumor tissue levels of total tissue inhibitor of metalloproteinases-1 (TIMP-1) and a poor prognosis of primary breast cancer patients. In the present study we investigated whether measurements of the uncomplexed fraction of TIMP-1 added prognostic information to that already obtained from total TIMP-1. We measured the uncomplexed fraction of TIMP-1, using a thoroughly validated ELISA specific for this fraction, in 341 tumor tissue extracts obtained from patients with primary breast cancer. These measurements were related to previously performed measurements of total TIMP-1 as well as to patient outcome. The observation time was 8.3 years (range, 7.3-11.3 years). During this period 136 patients died, and 153 patients experienced recurrence of disease. Cox regression analysis of recurrence-free survival (RFS) suggested that a score based on both uncomplexed and total TIMP-1, reflecting the tumor level of TIMP-1/MMP complexes, would be a more precise estimate of prognosis than total TIMP-1 alone. Univariate survival analysis showed a highly significant relationship between high values of the score and poor outcomes for RFS (p = 0.0002; hazard ratio = 2.7; 95% confidence interval, 1.5-4.8). Similar results were found for overall survival (p = 0.0001; hazard ratio = 3.3; 95% confidence interval, 1.8-6.3). Multivariate analysis of RFS and overall survival demonstrated that the score was significant including the classical prognostic factors used in breast cancer (p < 0.0001). The present study raises the hypothesis that it is the tumor level of TIMP-1/MMP complexes (i.e. activated matrix metalloproteinases) rather than TIMP-1 itself that determines prognosis, supporting the use of the combined score and not only total TIMP-1 in stratification of breast cancer patients.

Prognostic Significance of Stromelysin-3 and Tissue Inhibitor of Matrix Metalloproteinase-2 in Esophageal Cancer

OBJECTIVE

Stromelysins (matrix metalloproteinases: MMP-10 or ST-2 and MMP-11 or ST-3) and tissue inhibitors of matrix metalloproteinases (TIMP-1 and 2) have been shown to be associated with human tumor progression, invasion and metastasis. The aim of the present study was to determine the prognostic significance of these proteins in esophageal squamous cell carcinoma (ESCC).

METHODS

Immunohistochemical analysis was carried out in 65 surgically resected ESCCs and 49 distant histologically normal esophageal tissues and 16 cases of dysplasias. Statistical analyses were performed to determine the associations between the protein expression and clinicopathological parameters and survival of esophageal cancer patients.

RESULTS

Expression of ST-2, ST-3, TIMP-1 and TIMP-2 was observed in 43/65 (66%), 51/65 (78%), 43/65 (66%) and 47/65 (72%) ESCC cases, respectively. Univariate analysis showed that TIMP-2 expression was associated with tumor site (OR = 2.63, p = 0.017). TIMP-1+/TIMP-2+ phenotype was inversely correlated with nodal invasiveness of the tumor (OR = 0.4, p = 0.04). Interestingly, p53 expression was associated with increased levels of ST-3 (OR = 0.11, p = 0.02) and TIMP-1 (OR = 3.2, p = 0.007) suggesting possible involvement of p53 in the regulation of these proteins. An increased expression of ST-2, ST-3, TIMP-1 and TIMP-2 was observed in 11/16 (69%), 7/17 (44%), 11/16 (69%) and 8/16 (50%) dysplasias also suggesting that these alterations are early events in esophageal tumorigenesis. All the ESCC patients were followed up postesophagectomy for a maximum period of 59 months (mean disease-free survival = 12 months). Kaplan-Meier survival analysis showed that patients with ST-3-positive and TIMP-2-negative carcinoma had a significantly shorter disease-free survival (median disease-free survival time of 4 months) as compared to patients in the other groups (median disease-free survival time of 20 months; p = 0.0016). To our knowledge this is the first report showing that ST-3+/TIMP-2- phenotype remained of significant predictive value for disease-free survival (p = 0.0007) in multivariate analysis including a conventional clinicopathological factor, tumor stage (p = 0.051).

CONCLUSION

Our results suggest that ST-3+/TIMP-2- phenotype is an adverse prognosticator in esophageal cancer patients.

Tumor cell-mediated induction of the stromal factor stromelysin-3 requires heterotypic cell contact-dependent activation of specific protein kinase C isoforms

Stromelysin-3 (ST3, MMP-11) has been shown to be strongly overexpressed in stromal fibroblasts of most invasive human carcinomas. However, the molecular mechanisms leading to ST3 expression in nonmalignant fibroblasts remain unknown. The aim of the present study was to analyze the signaling pathways activated in normal pulmonary fibroblasts after their interaction with non-small cell lung cancer (NSCLC) cells and leading to ST3 expression. The use of selective signaling pathway inhibitors showed that conventional and novel protein kinase Cs (PKC) were required for ST3 induction, whereas Src kinases exerted a negative control. We observed by both conventional and real time confocal microscopy that green fluorescent protein-tagged PKCalpha and PKCepsilon, but not PKCdelta, transfected in fibroblasts, accumulate selectively at the cell-cell contacts between fibroblasts and tumor cells. In agreement, RNAi-mediated depletion of PKCalpha and PKCepsilon, but not PKCdelta significantly decreased co-culture-dependent ST3 production. Finally, a tetracycline-inducible expression model allowed us to confirm the central role of these PKC isoforms and the negative regulatory function of c-Src in the control of ST3 expression. Altogether, our data emphasize signaling changes occurring in the tumor microenvironment that may define new stromal targets for therapeutic intervention.

Stromelysin-3 expression is an early event in human oral tumorigenesis

Stromelysin-3 (ST3/MMP11) is associated with human tumour progression. To determine the clinical significance of ST3 in oral tumorigenesis, its expression was analysed in different stages of tobacco-associated oral cancer. Immunohistochemical analysis of ST3 expression in 79 oral precancerous lesions, 177 SCCs and 35 histologically normal oral tissues was carried out and corroborated by immunoblotting and RT-PCR. ST3/MMP11 protein expression was observed in 45/79 (57%) precancerous lesions [28/48 (58%) with hyperplasia and 17/31 (55%) with dysplasia] and in 123/177 (70%) oral SCCs. In precancerous lesions, ST3 expression was higher compared to normal oral tissues (p = 0.000) and associated with MVD (p = 0.05), a marker for angiogenesis. ST3 was also expressed in cells cultured from precancerous and cancerous lesions that had undergone epithelial-to-mesenchymal transition. In oral cancer patients, ST3 positivity was associated with lymph node involvement (p = 0.025) and increased intratumoral MVD (p = 0.009). Ninety-eight oral SCC patients were followed up for a period of 94 months (median 22.5 months). Kaplan-Meier survival analysis showed that ST3 expression was not a significant prognostic indicator. ST3 expression in oral hyperplastic and dysplastic lesions suggests its association with progression of phenotypic alterations acquired early during the malignant transformation pathway of oral epithelium and implicates it not only in angiogenesis and invasion but also in tumorigenesis. Thus, ST3 may serve as a potential target for developing molecular therapeutics for early intervention in oral tumorigenesis.

Stromal cell involvement in cancer

Solid tumors co-opt the body's endogenous extracellular proteolytic machinery for their invasion and metastasis. This is supported by a large number of independent observations ranging from histochemical and prognostic studies of cancer patient material to animal experiments. There are several extracellular proteolytic systems that are relevant in the context of cancer, but the plasminogen activation (PA) system and the matrix metalloproteases (MMPs) remain the most thoroughly investigated. Localization studies by immunohistochemistry and in situ mRNA hybridization in tumors of common human cancers have repeatedly identified members of the PA and MMP systems in stromal cells. The cancer cells, of epithelial origin, contribute PA and MMP components in some cases, but their contribution fades in comparison with the overwhelming expression of proteolytic components by fibroblasts, macrophages, endothelial cells, and other stromal cells. Ideal animal models of human cancers should recapitulate this fundamental proteolytic aspect of tumor biology. However, in the transplantable tumor models where PA or MMP components have been studied at the cellular level in vivo, this is most often not the case. Transgenic cancer models may provide a closer parallel to the human situation, in that PA and MMP components are synthesized by the tumor stroma. The pivotal role of stromal cells has been confirmed experimentally in mouse models in which the expression pattern of proteolytic components is strongly reminiscent of human tumors. In these models it is possible to reconstitute the wild-type tumor characteristics of proteolytically deficient tumor-bearing mice by transplantation with wild-type fibroblasts or hemapoietic cells. These studies collectively show that cancer-associated proteolysis is a collaborative effort of malignant cancer cells and various stromal cells--a collaboration in which stromal cells contribute the majority of the active proteolytic components that are necessary for the invasive behavior of the tumors. This cellular division of labor positions the stromal cells as prime targets for future research and possibly therapy. Vascular endothelial cells are already the focus of intense therapeutically relevant research, but tumor-associated fibroblasts, macrophages, neutrophils, lymphendothelial cells, etc. provide additional largely unexplored territory in the ongoing search for efficient countermeasures against invasive cancer.

Active stromelysin-3 (MMP-11) increases MCF-7 survival in three-dimensional Matrigel culture via activation of p42/p44 MAP-kinase

Stromelysin-3 (ST3) has the characteristic structure of matrix metalloproteinases (MMP), but its substrate specificity and pattern of expression differ markedly from that of other MMP family members. ST3 was originally isolated on the basis of its expression in primary breast cancers and has been shown to be overexpressed in virtually all primary carcinomas, suggesting that ST3 participates in the initial development of epithelial malignancies. Recent data using murine models reported that ST3 expression was able to increase tumor take by suppressing cell apoptosis. Our present goal was to set up an in vitro model in which we could study this new function. For this purpose, we analyzed survival of MCF-7 transfectants expressing either wild-type or catalytically inactive ST3 (ST3wt or ST3cat-) in three-dimensional (3-D) culture conditions by inclusion in Matrigel. In such conditions, that mimic the in vivo microenvironment, we found a marked decrease in the percentage of cell death when active ST3 was expressed (ST3wt transfectants vs. ST3cat- or vector only transfectants) as assessed by FACS and TUNEL analysis. The addition of batimastat, a broad spectrum MMP inhibitor, reversed the increased cell survival in ST3wt transfectants, confirming that ST3 enzymatic activity was required for this effect. Finally, we analyzed the expression of anti- and pro-apoptotic proteins as well as activation of cell survival pathways and we found that ST3-mediated cell survival was accompanied by activation of both p42/p44 MAPK and AKT. Our data confirm and extend the anti-apoptotic function of ST3 and provide a useful model to dissect this new role and identify new physiological substrates.

Identification of peptide substrates for human MMP-11 (stromelysin-3) using phage display

The MMP-11 proteinase, also known as stromelysin-3, probably plays an important role in human cancer because MMP-11 is frequently overexpressed in human tumors and MMP-11 levels affect tumorogenesis in mice. Unlike other MMPs, however, human MMP-11 does not cleave extracellular matrix proteins, such as collagen, laminin, fibronectin, and elastin. To help identify physiologic MMP-11 substrates, a phage display library was used to find peptide substrates for MMP-11. One class of peptides containing 26 members had the consensus sequence A(A/Q)(N/A) downward arrow (L/Y)(T/V/M/R)(R/K), where downward arrow denotes the cleavage site. This consensus sequence was similar to that for other MMPs, which also cleave peptides containing Ala in position 3, Ala in position 1, and Leu/Tyr in position 1', but differed from most other MMP substrates in that proline was rarely found in position 3 and Asn was frequently found in position 1. A second class of peptides containing four members had the consensus sequence G(G/A)E downward arrow LR. Although other MMPs also cleave peptides with these residues, other MMPs prefer proline at position 3 in this sequence. In vitro assays with MMP-11 and representative peptides from both classes yielded modest kcat/Km values relative to values found for other MMPs with their preferred peptide substrates. These reactions also showed that peptides with proline in position 3 were poor substrates for MMP-11. A structural basis for the lower kcat/Km values of human MMP-11, relative to other MMPs, and poor cleavage of position 3 proline substrates by MMP-11 is provided. Taken together, these findings explain why MMP-11 does not cleave most other MMP substrates and predict that MMP-11 has unique substrates that may contribute to human cancer.

Expression of ADAM-9 mRNA and protein in human breast cancer

The ADAMs (a disintegrin and metalloprotease) are membrane proteins containing both protease and adhesion domains and thus may be potentially important in cancer invasion and metastasis. The aim of our study was to investigate the distribution and potential clinical significance of ADAM-9 in breast cancer. ADAM-9 expression was measured using both reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. ADAM-9 mRNA was expressed more frequently in both breast carcinomas (72/110, 66%) and fibroadenomas (21/38, 55%) compared to normal breast tissue (6/25, 24%) (p = 0.0004, p = 0.028, respectively). Multiple forms of ADAM-9 protein were detected by Western blotting, i.e., at 124, 84 and 48 kDa under reducing conditions and at 115, 76, 55, 52 and 46 kDa under nonreducing conditions. The 84 and 55 kDa forms were detected more frequently in the primary cancers compared to normal breast tissue (p < 0.0001, p = 0.0002, respectively). In addition, relative levels of the 84 kDa mature form were significantly higher in the primary cancers than in the fibroadenomas (p = 0.003), while the reverse was found for the 124 kDa precursor form (p = 0.026). In the carcinomas, the 84 kDa form of ADAM-9 protein was expressed at higher levels in node-positive than node-negative cancers (p = 0.05) and correlated positively with HER-2/neu protein levels (r = 0.313, p = 0.016). This is the first report to describe expression of any ADAM in a large number of human carcinomas.

Matrix metalloproteinases in tumor-host cell communication

The microenvironment or stroma immediately surrounding tumor cells consists of a three-dimensional extracellular matrix (ECM) and stromal cells such as fibroblasts and inflammatory cells. The matrix metalloproteinases (MMPs) constitute a family of over 24 members, which collectively are capable of degrading virtually the entire ECM. Strict regulation of MMP expression is critical in order to maintain proper ECM homeostasis, but in disease states such as cancer there is often a high level of MMP activity at the tumor-stroma interface. Several studies have documented the importance of MMP-mediated ECM destruction in the successful dissemination of several tumor types, but it has become increasingly clear that they are also involved in earlier stages of tumorigenesis. MMPs are implicated in a wide variety of roles that can assist tumor initiation, growth, migration, angiogenesis, the selection of apoptosis-resistant subpopulations, and in invasion and metastasis. Interestingly, the factors responsible for many of these effects are derived from the cell surfaces of the tumor or stromal cells or are embedded in the ECM. Therefore, the MMPs can no longer be thought of solely as ECM destructionists, but as part of an elegant communication system through which the tumor interacts with the stroma.

Stromelysin-3 expression by mammary tumor-associated fibroblasts under in vitro breast cancer cell induction

To understand better the influence of the host stromal phenotype on stromal expression of stromelysin-3 (ST3) in breast cancer, we have investigated ST3 expression by host stromal cells isolated from 9 different primary breast carcinomas. These tumor-associated fibroblasts were cocultivated with 3 epithelial cancer cell lines of mammary origin (MDA-MB-231, SK-BR-3 and MCF-7), as well as with normal human mammary epithelial cells (NME and 184A1) and keratinocytes, using both direct and indirect coculture systems. ST3 expression was demonstrated by both in situ hybridization and immunocytochemistry. The results showed that ST3 expression by stromal cells was cancer-specific. Indeed, ST3 expression by tumor-associated stromal cells was induced by 3 malignant cancer cell lines (MDA-MB-231, SK-BR-3 and MCF-7), whereas no ST3 was expressed under normal mammary epithelial cell stimulation. ST3 expression was weak or absent in unstimulated tumor-associated fibroblasts. However, after direct coculture with cancer cells, expression of ST3 transcripts reappeared in 8 of the 9 cases and was observed only in fibroblasts located in close contact with tumor cells. Under similar coculture conditions and using the same cancer cell line stimulation, ST3 expression was, however, quite variable among these 9 cases, reflecting the difference of protease expression observed on the sections of the original tumors. Tumor induction of ST3 expression was much more important by direct cell-cell contact than by indirect stimulation and was not influenced by the addition of basic fibroblast growth factor (bFGF) and anti-bFGF to the culture medium. Our results suggest that the host stromal cell phenotype may significantly influence host stromal cell protease expression under cancer cell stimulation.

Matrix metalloproteinases in cancer: prognostic markers and therapeutic targets

Degradation of extracellular matrix is crucial for malignant tumour growth, invasion, metastasis and angiogenesis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent neutral endopeptidases collectively capable of degrading essentially all matrix components. Elevated levels of distinct MMPs can be detected in tumour tissue or serum of patients with advanced cancer and their role as prognostic indicators in cancer is studied. In addition, therapeutic intervention of tumour growth and invasion based on inhibition of MMP activity is under intensive investigation and several MMP inhibitors are in clinical trials in cancer. In this review, we discuss the current view on the feasibility of MMPs as prognostic markers and as targets for therapeutic intervention in cancer.

Stromelysin-3 is expressed by aggressive meningiomas

BACKGROUND

Stromelysin-3 (ST3) that belongs to the metalloproteinase family is proposed to play a role in tumor invasion. The purpose of this work was to study the variation of ST3 expression in meningiomas.

METHODS

Twenty atypical meningiomas were retrieved from the Pathology Department's files at Hopital de Bellevue, Saint-Etienne, France. They were compared with 20 benign meningiomas randomly selected from the same file. The tumors were classified using standard histologic criteria. Frozen sections of the tumors were immunostained for ST3 and MIB-1 to evaluate the proliferative activity of tumor cells.

RESULTS

The study included 5 fibrous meningiomas, 10 transitional meningiomas, 20 syncitial meningiomas, 2 secretory meningiomas, 2 microcystic meningiomas, and 1 angiomatous meningioma. Stromelysin-3 was expressed within the stromal and neoplastic cells of only 1 benign meningioma and 13 atypical meningiomas. The MIB-1 proliferation index was significantly higher in the meningiomas expressing ST3 (Student t test: P < 0.001). The invasion of bone, muscle, and brain by meningiomas as well the recurrence were statistically correlated with their ST3 expression (Kruskal-Wallis nonparametric correlation test, P = 0.001 and P = 0.008, respectively).

CONCLUSIONS

Stromelysin-3 might play an important role in the invasiveness of meningiomas. Therefore, considering, ST3 in association with evaluation of the MIB-1 proliferating index may be an useful tool to assess the behavior of meningiomas.

Expression of cathepsin D, stromelysin-3, and urokinase by reactive stromal cells on breast carcinoma prognosis

BACKGROUND

Current literature suggests that several proteases act in a cascade to mediate remodeling of the extracellular matrix and favor cancer progression. Others and the authors of this study recently identified cathepsin D, stromelysin-3, and urokinase plasminogen activator (uPA) expression by reactive stromal cells as significant factors of poor prognosis in breast carcinoma. The authors evaluated the joint effect of protease expression on cancer aggressiveness.

METHODS

Protease expression was analyzed by immunohistochemistry (cathepsin D) and in situ hybridization (stromelysin-3 and uPA) on formalin fixed paraffin embedded specimens from 557 breast carcinomas without distant metastasis at diagnosis and with an average of 10 years of follow-up.

RESULTS

Of the 557 breast carcinomas, 80 (14.3%) expressed all 3 proteases, and 134 (24%) expressed none of them. An adjusted Cox model revealed significantly worse distant metastasis free survival (DMFS) with expression of all three proteases (P < 0.0001). The DMFS of patients whose tumor lacked at least one of the three proteases was similar to that of patients without any protease expression, irrespective of the type or number of proteases missing.

CONCLUSIONS

This study suggests that proteases expressed by reactive stromal cells are interdependent and that a breach in the protease pathway may impair breast carcinoma progression.

Matrix metalloproteinase inhibitors: past lessons and future prospects in breast cancer

The matrix metalloproteinases (MMPs) play a central role in invasion and metastasis. However, despite striking activity in preclinical models, the clinical development of the matrix metalloproteinase inhibitors (MMPIs) has been difficult. The results of important phase III trials are now emerging and it is therefore opportune to review the current state of the MMPIs. In this article the evidence for the role of MMPs in the progression of breast cancer, the development of the MMPIs and the recent phase III results are discussed. Despite the problems encountered it is hoped that the MMPIs may yet provide another mechanism for the long-term control of micrometastatic disease. Furthermore, important lessons can be learnt from their development that are relevant to the development of other biological agents.

Elevated furin expression in aggressive human head and neck tumors and tumor cell lines

Pro-protein convertases (PCs) are proteases that recognize and cleave precursor proteins. Furin, a well-studied PC, is ubiquitously expressed, and it has been implicated in many physiological and pathological processes. Some substrates for furin, such as membrane type 1 (MT1) matrix metalloproteinase (MMP), an MMP that activates gelatinase, a collagen-degrading enzyme, are associated with the advanced malignant phenotype. This report examines the expression of furin in carcinoma cell lines of different invasive ability. The levels of furin mRNA and protein correlated with the aggressiveness of tumor cell lines derived from head and neck and lung cancers. Furin expression also was investigated in primary head and neck squamous cell carcinomas (HNSCCs). Furin mRNA was not detected in nonmetastasizing carcinomas. In contrast, furin mRNA was expressed in metastasizing HNSCCs. Immunohistochemistry and Western blot analysis confirmed these results at the protein level. Furin activity was investigated indirectly by evaluating the expression of the pro-form and the processed form of MT1-MMP. Metastasizing HNSCCs showed increased expression of MT1-MMP. Furthermore, pro-MT1-MMP expression was noted in most of the nonmetastasizing HNSCCs analyzed by Western blot, and it was absent in the metastasizing HNSCCs. This finding suggests a lower level of furin-mediated MT1-MMP activation in the less aggressive cancers. These observations indicate that furin plays a role in tumor progression. Its overexpression in more aggressive or metastasizing cancers resulted in increased MMP processing.

Functional role of matrix metalloproteinases (MMPs) in mammary epithelial cell development

The extracellular matrix (ECM) is an important regulator of mammary epithelial cell (MEC) function and is remodeled by matrix metalloproteinases (MMPs). To investigate the significance and regulation of MMP activity in normal MEC, we utilized a primary culture model in which rat MEC were grown three dimensionally within a reconstituted basement membrane (RBM) in defined serum-free medium. Zymograms of culture medium demonstrated that five major gelatinases of 97, 80, 74, 69, and 65 kDa were secreted by MEC and were distinct from gelatinases of RBM origin. Based on molecular weight, p-aminophenylmercuric acid activation, immunoblotting with MMP-specific antibodies, inhibition by EDTA, a peptide containing the prodomain sequence of MMP (TMRKPRCGNPDVAN) and two synthetic MMP inhibitors (BB-94 and CGS 27023A), these were classified as inactive and active forms of MMP-9 and MMP-2. The maximal MMP activities occurred when MEC were in a rapid proliferation and branching phase and declined after they underwent functional differentiation. Known regulators of MEC growth and differentiation were evaluated for their ability to modulate gelatinase activity in primary culture. Secretion of one or both MMPs was inhibited by EGF, TGFalpha, prolactin, and hydrocortisone and stimulated by progesterone. Furthermore, the functional significance of MMPs was demonstrated since three MMP inhibitors blocked branching morphogenesis elicited by the absence of hydrocortisone. Additionally, two synthetic MMP inhibitors not only inhibited epithelial cell growth but also inhibited normal alveolar development of the MEC. Finally, these drugs were found to enhance MMP secretion from MEC, although the activity of the secreted MMPs was inhibited as long as the drug was present.

Crystal structure of the stromelysin-3 (MMP-11) catalytic domain complexed with a phosphinic inhibitor mimicking the transition-state

Stromelysin-3 (ST3) is a matrix metalloproteinase (MMP-11) whose proteolytic activity plays an important role in tumorigenicity enhancement. In breast cancer, ST3 is a bad prognosis marker: its expression is associated with a poor clinical outcome. This enzyme therefore represents an attractive therapeutic target. The topology of matrix metalloproteinases (MMPs) is remarkably well conserved, making the design of highly specific inhibitors difficult. The major difference between MMPs lies in the S(1)' subsite, a well-defined hydrophobic pocket of variable depth. The present crystal structure, the first 3D-structure of the ST3 catalytic domain in interaction with a phosphinic inhibitor mimicking a (d, l) peptide, clearly demonstrates that its S(1)' pocket corresponds to a tunnel running through the enzyme. This open channel is filled by the inhibitor P(1)' group which adopts a constrained conformation to fit this pocket, together with two water molecules interacting with the ST3-specific residue Gln215. These observations provide clues for the design of more specific inhibitors and show how ST3 can accommodate a phosphinic inhibitor mimicking a (d, l) peptide. The presence of a water molecule interacting with one oxygen atom of the inhibitor phosphinyl group and the proline residue of the Met-turn suggests how the intermediate formed during proteolysis may be stabilized. Furthermore, the hydrogen bond distance observed between the methyl of the phosphinic group and the carbonyl group of Ala182 mimics the interaction between this carbonyl group and the amide group of the cleaved peptidic bond. Our crystal structure provides a good model to study the MMPs mechanism of proteolysis.

Quantification of matrix metalloproteinase activity in plasma of patients enrolled in a BAY 12-9566 phase I study

The expression of matrix metalloproteinases (MMPs) is often associated with invasiveness or grade of tumours. Increased blood levels of MMP proteins, including MMP-1, MMP-2, MMP-3 and MMP-9 have been detected in various types of cancers. With the exception of one study, MMPs in serum and plasma have been determined using ELISA. In the present study we measured the activity of the MMPs found in human plasma samples using gelatin enzymography and fluorimetric degradation assays. We used plasma samples from healthy control subjects and cancer patients enrolled in a dose-finding study for the MMP inhibitor, BAY 12-9566, to assess the activity of MMPs found in plasma and screen for efficacy of the MMP inhibitor. BAY 12-9566 has inhibitory activity toward MMP-2, MMP-3 and MMP-9. Patients with advanced solid tumours were enrolled in our study and plasma was collected on day 1 before dosing and at steady-state of the drug on day 15. Our results show that BAY 12-9566 was effective in lowering the plasma gelatinolytic activity in the group of 29 patients when considering the data obtained from a fluorimetric gelatinase assay. The data obtained from gelatin enzymography, however, did not reach significance. The fluorimetric degradation assay could be a useful tool to screen plasma from cancer patients in other clinical trials assessing MMP inhibitors.

Multiple regulatory elements in the murine stromelysin-3 promoter. Evidence for direct control by CCAAT/enhancer-binding protein beta and thyroid and retinoid receptors

Stromelysin-3 (ST3) belongs to the matrix metalloproteinase (MMPs) family, a protease family involved in tissue remodeling. Although this family of enzymes is regulated by nuclear receptors, few hormone-responsive elements have been demonstrated in MMP promoters. In order to identify regulatory elements and/or factors that control the expression of the mouse st3 gene, we have analyzed genomic sequences encompassing 5 kilobase pairs of the ST3 promoter. Analysis of these sequences revealed several CCAAT/enhancer-binding proteins (C/EBP) and retinoic acid-responsive elements (RAREs), as well as one thyroid-responsive element. However, in contrast to most MMP promoters, no AP-1-binding sites were identified. Specific binding activities were demonstrated for all elements. Consistent with previous reports, retinoid X receptor is required for maximal binding to the ST3 RAREs and the TRE. The ST3-C/EBP element was shown to mediate dose-dependent promoter activation by C/EBPbeta. Among the RAREs, the proximal DR1-RARE was shown to be sufficient for ST3 promoter activation by ligand-bound retinoid receptors, whereas the two distal DR2-RAREs appear to be involved more in the control of base-line promoter activity. Accordingly, ST3 expression was induced by retinoic acid and was reduced in cells where specific retinoic acid receptors had been inactivated. The involvement of these conserved regulatory elements is discussed in the context of physiological or pathological situations associated with st3 expression. Our findings therefore assign to C/EBP, retinoids, and thyroid hormone important roles in the regulation of ST3 gene expression.

New paradigms for the treatment of cancer: the role of anti-angiogenesis agents

Angiogenesis, the sprouting of new blood vessels, plays a role in diverse disease states including cancer, diabetic retinopathy, age-related macular degeneration, rheumatoid arthritis, psoriasis, atherosclerosis, and restenosis. With regard to cancer, the clinical association of tumor vascularity with tumor aggressiveness has been clearly demonstrated in numerous tumor types. The observation of increased microvessel density in tumors not only serves as an independent prognostic indicator, but also suggests that anti-angiogenic therapy may be an important component of treatment regimens for cancer patients. The complexity of the angiogenic process, which involves both positive and negative regulators, provides a number of targets for therapy. Many positive regulators, including growth factor receptors, matrix metalloproteinases, and integrins, have been correlated with increased vascularity of tumors and poor prognosis for patient survival. Thus, these serve as ideal targets for anti-angiogenesis therapy. Many inhibitors of these targets are currently undergoing clinical evaluation as potential anti-cancer agents. In this article, we discuss the role of positive regulators in angiogenesis and tumor growth and describe the anti-angiogenic agents under development.

Target molecules for anti-angiogenic therapy: from basic research to clinical trials

There is growing evidence that anti-angiogenic drugs will improve future therapies of diseases like cancer, rheumatoid arthritis and ocular neovascularisation. However, it is still uncertain which kind of substance, out of the large number of angiogenesis inhibitors, will prove to be a suitable agent to treat these human diseases. There are currently more than 30 angiogenesis inhibitors in clinical trials and a multitude of promising new candidates are under investigation in vitro and in animal models. Important therapeutic strategies are: suppression of activity of the major angiogenic regulators like vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF); inhibition of function of alphav-integrins and matrix metalloproteinases (MMPs); the exploitation of endogenous anti-angiogenic molecules like angiostatin, endostatin or thrombospondin. Given the wide spectrum of diseases which could be treated by anti-angiogenic compounds, it is important for today's clinicians to understand their essential mode of action at a cellular and molecular level. Here we give an in-depth overview of the basic pathophysiological mechanisms underlying the different anti-angiogenic approaches used to date based on the most recent fundamental and clinical research data. The angiogenesis inhibitors in clinical trials are presented and promising future drug candidates are discussed.

Demonstration in vivo that stromelysin-3 functions through its proteolytic activity

Stromelysin-3 (ST3), a matrix metalloproteinase (MMP) expressed in aggressive carcinomas, has been shown to promote tumor development in different in vivo experimental models. However, the inability of its mature form to degrade extracellular matrix components casts doubt on whether ST3 functions in vivo as a protease. In this study, we evaluated whether the ST3 tumor-promoting effect could be ascribed to its proteolytic activity and whether this putative protease could be targeted with MMP inhibitors. Catalytically inactive mutant cDNA of human (h) ST3 or mouse (m) ST3 were generated and transfected into MCF7 cells. When injected into nude mice in the presence of matrigel, the mutant-bearing cells did not exhibit the enhanced tumorigenicity elicited by MCF7 cells transfected with wild-type ST3 cDNA. In a second approach, TIMP2 overproduction in MCF7 cells expressing hST3 was induced by retroviral infection. The co-expression of ST3 and TIMP2 failed to enhance the tumorigenicity of MCF7 cells. Notably, matrigel depleted of low-molecular-weight proteins and growth factors failed to promote the tumorigenicity of ST3-expressing MCF7 cells. These findings provide the first in vivo evidence that ST3 is indeed a protease that can modulate cancer progression by remodeling extracellular matrix and probably by inducing it to release the necessary microenvironmental factors. Thus, ST3 represents an interesting target for specific MMP inhibition.

Matrix metalloproteinases: biologic activity and clinical implications

Tumor progression is a complex, multistage process by which a normal cell undergoes genetic changes that result in phenotypic alterations and the acquisition of the ability to spread and colonize distant sites in the body. Although many factors regulate malignant tumor growth and spread, interactions between a tumor and its surrounding microenvironment result in the production of important protein products that are crucial to each step of tumor progression. The matrix metalloproteinases (MMPs) are a family of degradative enzymes with clear links to malignancy. These enzymes are associated with tumor cell invasion of the basement membrane and stroma, blood vessel penetration, and metastasis. They have more recently been implicated in primary and metastatic tumor growth and angiogenesis, and they may even have a role in tumor promotion. This review outlines our current understanding of the MMP family, including the association of particular MMPs with malignant phenotypes and the role of MMPs in specific steps of the metastatic cascade. As scientific understanding of the MMPs has advanced, therapeutic strategies that capitalize on blocking the enzymes have rapidly developed. The preclinical and clinical evolution of the synthetic MMP inhibitors (MMPIs) is also examined, with the discussion encompassing important methodologic issues associated with determining clinical efficacy of MMPIs and other novel therapeutic agents.