Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human pancreatic adenocarcinomas: clinicopathologic and prognostic significance of matrilysin expression

Toward development of a surface-enhanced Raman scattering (SERS)-based cancer diagnostic immunoassay panel

Proteomic analyses of readily obtained human fluids (e.g., serum, urine, and saliva) indicate that the diagnosis of complex diseases will be enhanced by the simultaneous measurement of multiple biomarkers from such samples. This paper describes the development of a nanoparticle-based multiplexed platform that has the potential for simultaneous read-out of large numbers of biomolecules. For this purpose, we have chosen pancreatic adenocarcinoma (PA) as a test bed for diagnosis and prognosis. PA is a devastating form of cancer in which an estimated 86% of diagnoses resulted in death in the United States in 2010. The high mortality rate is due, in part, to the asymptomatic development of the disease and the dearth of sensitive diagnostics available for early detection. One promising route lies in the development of a serum biomarker panel that can generate a signature unique to early stage PA. We describe the design and development of a proof-of-concept PA biomarker immunoassay array coupled with surface-enhanced Raman scattering (SERS) as a sensitive readout method.

The pancreas cancer microenvironment

Pancreatic ductal adenocarcinoma (PDA) is a common and lethal malignancy resulting in more than 250,000 deaths per year worldwide. Despite extensive efforts, cytotoxic and targeted therapies have provided only limited efficacy for patients with PDA to date. One contributing factor to the failure of systemic therapies may be the abundant tumor stromal content that is the characteristic of PDA. The PDA stroma, aptly termed the tumor microenvironment, occupies the majority of the tumor mass, and consists of a dynamic assortment of extracellular matrix components and nonneoplastic cells including fibroblastic, vascular, and immune cells. Recent work has revealed that the PDA stroma supports tumor growth and promotes metastasis and simultaneously serves as a physical barrier to drug delivery. Accordingly, methods that alter stromal composition or function, for instance interference with the vasculature via Notch/Hedgehog pathway inhibition or relief of vascular compression by hyaluronidase, are under active investigation. Here, we will review our current understanding of the PDA tumor microenvironment, and highlight opportunities for further exploration that may benefit patients.

REG4 contributes to the invasiveness of pancreatic cancer by upregulating MMP-7 and MMP-9

Recent studies have shown that overexpression of regenerating gene family member 4 (REG4) is associated with the initiation and progression of pancreatic cancer. In our study, we explored the role of REG4 in the invasion of pancreatic cancer. Real-time PCR and Western blot analysis were used to determine REG4 expression in pancreatic cancer cell lines. An MTT assay was carried out to test the effect of REG4 on the growth of pancreatic cancer cells. The involvement of REG4 in cancer cell invasion was examined by Transwell invasion assay. Two MMPs, MMP-7 and MMP-9, were identified from a pool of candidate genes as being related to REG4-induced cell invasion by PCR and Western blotting. Immunohistochemistry was used to confirm the correlation between REG4 and the two MMPs. High expression of REG4 was found in BXPC-3 cells and its culture media. But in PANC-1 and ASPC-1 cell lines, REG4 expression levels were very low, and no detectable protein was found in the culture medium. The MTT and Transwell invasion assays showed that recombinant REG4 protein and BXPC-3 conditioned media significantly promoted the proliferation and invasiveness of pancreatic cancer cells. It was also shown that MMP-7 and MMP-9 are upregulated by REG4 induction using real-time PCR and Western blotting analysis. Immunohistochemical study further verified this result. In conclusion, REG4 promotes not only growth but also in vitro invasiveness of pancreatic cancer cells by upregulating MMP-7 and MMP-9.

Genome-wide characterization of pancreatic adenocarcinoma patients using next generation sequencing

Pancreatic adenocarcinoma (PAC) is among the most lethal malignancies. While research has implicated multiple genes in disease pathogenesis, identification of therapeutic leads has been difficult and the majority of currently available therapies provide only marginal benefit. To address this issue, our goal was to genomically characterize individual PAC patients to understand the range of aberrations that are occurring in each tumor. Because our understanding of PAC tumorigenesis is limited, evaluation of separate cases may reveal aberrations, that are less common but may provide relevant information on the disease, or that may represent viable therapeutic targets for the patient. We used next generation sequencing to assess global somatic events across 3 PAC patients to characterize each patient and to identify potential targets. This study is the first to report whole genome sequencing (WGS) findings in paired tumor/normal samples collected from 3 separate PAC patients. We generated on average 132 billion mappable bases across all patients using WGS, and identified 142 somatic coding events including point mutations, insertion/deletions, and chromosomal copy number variants. We did not identify any significant somatic translocation events. We also performed RNA sequencing on 2 of these patients' tumors for which tumor RNA was available to evaluate expression changes that may be associated with somatic events, and generated over 100 million mapped reads for each patient. We further performed pathway analysis of all sequencing data to identify processes that may be the most heavily impacted from somatic and expression alterations. As expected, the KRAS signaling pathway was the most heavily impacted pathway (P<0.05), along with tumor-stroma interactions and tumor suppressive pathways. While sequencing of more patients is needed, the high resolution genomic and transcriptomic information we have acquired here provides valuable information on the molecular composition of PAC and helps to establish a foundation for improved therapeutic selection.

Genome-wide characterization of pancreatic adenocarcinoma patients using next generation sequencing

Pancreatic adenocarcinoma (PAC) is among the most lethal malignancies. While research has implicated multiple genes in disease pathogenesis, identification of therapeutic leads has been difficult and the majority of currently available therapies provide only marginal benefit. To address this issue, our goal was to genomically characterize individual PAC patients to understand the range of aberrations that are occurring in each tumor. Because our understanding of PAC tumorigenesis is limited, evaluation of separate cases may reveal aberrations, that are less common but may provide relevant information on the disease, or that may represent viable therapeutic targets for the patient. We used next generation sequencing to assess global somatic events across 3 PAC patients to characterize each patient and to identify potential targets. This study is the first to report whole genome sequencing (WGS) findings in paired tumor/normal samples collected from 3 separate PAC patients. We generated on average 132 billion mappable bases across all patients using WGS, and identified 142 somatic coding events including point mutations, insertion/deletions, and chromosomal copy number variants. We did not identify any significant somatic translocation events. We also performed RNA sequencing on 2 of these patients' tumors for which tumor RNA was available to evaluate expression changes that may be associated with somatic events, and generated over 100 million mapped reads for each patient. We further performed pathway analysis of all sequencing data to identify processes that may be the most heavily impacted from somatic and expression alterations. As expected, the KRAS signaling pathway was the most heavily impacted pathway (P<0.05), along with tumor-stroma interactions and tumor suppressive pathways. While sequencing of more patients is needed, the high resolution genomic and transcriptomic information we have acquired here provides valuable information on the molecular composition of PAC and helps to establish a foundation for improved therapeutic selection.

Involvement of inflammatory factors in pancreatic carcinogenesis and preventive effects of anti-inflammatory agents

Chronic inflammation is known to be a risk for many cancers, including pancreatic cancer. Heavy alcohol drinking and cigarette smoking are major causes of pancreatitis, and epidemiological studies have shown that smoking and chronic pancreatitis are risk factors for pancreatic cancer. Meanwhile, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are elevated in pancreatitis and pancreatic cancer tissues in humans and in animal models. Selective inhibitors of iNOS and COX-2 suppress pancreatic cancer development in a chemical carcinogenesis model of hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). In addition, hyperlipidemia, obesity, and type II diabetes are also suggested to be associated with chronic inflammation in the pancreas and involved in pancreatic cancer development. We have shown that a high-fat diet increased pancreatic cancer development in BOP-treated hamsters, along with aggravation of hyperlipidemia, severe fatty infiltration, and increased expression of adipokines and inflammatory factors in the pancreas. Of note, fatty pancreas has been observed in obese and/or diabetic cases in humans. Preventive effects of anti-hyperlipidemic/anti-diabetic agents on pancreatic cancer have also been shown in humans and animals. Taking this evidence into consideration, modulation of inflammatory factors by anti-inflammatory agents will provide useful data for prevention of pancreatic cancer.

Keratinocyte growth factor induces matrix metalloproteinase-9 expression and correlates with venous invasion in pancreatic cancer

Keratinocyte growth factor (KGF), also known as fibroblast growth factor-7, and KGF receptor (KGFR) play important roles in the growth of epithelial cells and are overexpressed in a variety of malignant epithelial tumors, including pancreatic ductal adenocarcinoma (PDAC). We previously reported that co-expression of KGF and KGFR in PDAC is associated with venous invasion, enhanced vascular endothelial growth factor A expression and poor prognosis. Matrix metalloproteinase-9 (MMP-9) is known to participate in the degradation of type IV collagen, which is a primary component of extracellular matrices in the vascular basement membrane. In the present study, we examined the expression and roles of KGF, KGFR and MMP-9 in human PDAC cell lines and tissues. Quantitative real-time polymerase chain reaction analysis demonstrated the expression of MMP-9 mRNA in all eight PDAC cell lines. KGF, KGFR and MMP-9 were, respectively, expressed in 27 (43%), 23 (37%) and 35 (56%) of 63 patients. Each expression of KGF, KGFR or MMP-9 correlated positively with venous invasion. Furthermore, expression of KGF or MMP-9 correlated positively with liver metastasis. KGF-positive cases exhibited shorter survival than KGF-negative cases, while KGFR and MMP-9 expression were unrelated to prognosis. Administration of recombinant human KGF increased MMP-9 expression in PDAC cells, while transient transfection with short hairpin RNAs targeting KGF transcripts reduced MMP-9 expression in PDAC cells. Moreover, recombinant human KGF significantly enhanced migration and invasion of PDAC cells. These findings suggest that KGF and KGFR promote venous invasion via MMP-9 in PDAC, and closely correlate with liver metastasis. The KGF/KGFR pathway may be a critical therapeutic target for PDAC metastasis.

Human matrix metalloproteinases: an ubiquitarian class of enzymes involved in several pathological processes

Human matrix metalloproteinases (MMPs) belong to the M10 family of the MA clan of endopeptidases. They are ubiquitarian enzymes, structurally characterized by an active site where a Zn(2+) atom, coordinated by three histidines, plays the catalytic role, assisted by a glutamic acid as a general base. Various MMPs display different domain composition, which is very important for macromolecular substrates recognition. Substrate specificity is very different among MMPs, being often associated to their cellular compartmentalization and/or cellular type where they are expressed. An extensive review of the different MMPs structural and functional features is integrated with their pathological role in several types of diseases, spanning from cancer to cardiovascular diseases and to neurodegeneration. It emerges a very complex and crucial role played by these enzymes in many physiological and pathological processes.

The effect of a novel frizzled 8-related antiproliferative factor on in vitro carcinoma and melanoma cell proliferation and invasion

Antiproliferative factor (APF) is a potent frizzled protein 8-related sialoglycopeptide inhibitor of bladder epithelial cell proliferation that mediates its activity by binding to cytoskeletal associated protein 4 in the cell membrane. Synthetic asialylated APF (as-APF) (Galβ1-3GalNAcα-O-TVPAAVVVA) was previously shown to inhibit both normal bladder epithelial as well as T24 bladder carcinoma cell proliferation and heparin-binding epidermal growth factor-like growth factor (HB-EGF) production at low nanomolar concentrations, and an L: -pipecolic acid derivative (Galβ1-3GalNAcα-O-TV-pipecolic acid-AAVVVA) was also shown to inhibit normal bladder epithelial cell proliferation. To better determine their spectrum of activity, we measured the effects of these APF derivatives on the proliferation of cells derived from additional urologic carcinomas (bladder and kidney), non-urologic carcinomas (ovary, lung, colon, pancreas, and breast), and melanomas using a (3)H-thymidine incorporation assay. We also measured the effects of as-APF on cell HB-EGF and matrix metalloproteinase (MMP2) secretion plus cell invasion, using qRT-PCR, Western blot and an in vitro invasion assay. L: -pipecolic acid as-APF and/or as-APF significantly inhibited proliferation of each cell line in a dose-dependent manner with IC(50)'s in the nanomolar range, regardless of tissue origin, cell type (carcinoma vs. melanoma), or p53 or ras mutation status. as-APF also inhibited HB-EGF and MMP2 production plus in vitro invasion of tested bladder, kidney, breast, lung, and melanoma tumor cell lines, in a dose-dependent manner (IC(50) = 1-100 nM). Synthetic APF derivatives are potent inhibitors of urologic and non-urologic carcinoma plus melanoma cell proliferation, MMP2 production, and invasion, and may be useful for development as adjunctive antitumor therapy(ies).

Claudin-4 expression predicts survival in pancreatic ductal adenocarcinoma

BACKGROUND

Identification of prognostic markers would be useful in the clinical management of patients with pancreatic ductal adenocarcinoma (PDAC). The clinical relevance of claudin-4 (CLDN4), recently identified as overexpressed in PDAC, is unknown.

METHODS

Using quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR), we analyzed CLDN4 mRNA expression in a panel of 9 pancreatic cancer cell lines and formalin-fixed paraffin-embedded (FFPE) tissues from 100 patients with PDAC. The CLDN4 expression levels were then correlated with clinicopathological variables and patient outcome. We also performed immunohistochemical analysis in 20 FFPE samples of PDAC to investigate the expression of CLDN4 protein.

RESULTS

Increased expression of CLDN4 was confirmed in all the pancreatic cancer cell lines tested compared with normal ductal epithelial cells and fibroblasts. We found that low expression of CLDN4 was significantly associated with shorter survival in patients with PDAC (hazard ratio; 1.362, 95% confidence interval; 1.011-1.873, P = 0.0419). Patients with high CLDN4 expression survived longer for a median of 63.0 months, compared with 14.7 months in patients with low CLDN4 expression (P = 0.0067). In immunohistochemical analysis, the level of CLDN4 mRNA expression was significantly correlated with the expression of CLDN4 protein (P = 0.0168).

CONCLUSION

Increased expression of CLDN4 mRNA predicts better prognosis in PDAC.

Systematic review of immunohistochemical biomarkers to identify prognostic subgroups of patients with pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) carries a dismal prognosis. There is a need to identify prognostic subtypes of PDAC to predict clinical and therapeutic outcomes accurately, and define novel therapeutic targets. The purpose of this review was to provide a systematic summary and review of available data on immunohistochemical (IHC) prognostic and predictive markers in patients with PDAC.

METHODS

Relevant articles in English published between January 1990 and June 2010 were obtained from PubMed searches. Other articles identified from cross-checking references and additional sources were reviewed. The inclusion was limited to studies evaluating IHC markers in a multivariable setting.

RESULTS

Database searches identified 76 independent prognostic and predictive molecular markers implicated in pancreatic tumour growth, apoptosis, angiogenesis, invasion and resistance to chemotherapy. Of these, 11 markers (Ki-67, p27, p53, transforming growth factor β1, Bcl-2, survivin, vascular endothelial growth factor, cyclo-oxygenase 2, CD34, S100A4 and human equilibrative nucleoside transporter 1) provided independent prognostic or predictive information in two or more separate studies.

CONCLUSION

None of the molecular markers described can be recommended for routine clinical use as they were identified in small cohorts and there were inconsistencies between studies. Their prognostic and predictive values need to be validated further in prospective multicentre studies in larger patient populations. A panel of molecular markers may become useful in predicting individual patient outcome and directing novel types of intervention.

Single-nucleotide polymorphisms of matrix metalloproteinases and their inhibitors in gastrointestinal cancer

Matrix metalloproteinases (MMPs) are implicated in cancer development and progression and are associated with prognosis. Single-nucleotide polymorphisms (SNPs) of MMPs, most frequently located in the promoter region of the genes, have been shown to influence cancer susceptibility and/or progression. SNPs of MMP-1, -2, -3, -7, -8, -9, -12, -13 and -21 and of the tissue inhibitor of metalloproteinases (TIMPs) TIMP-1 and TIMP-2 have been studied in digestive tract tumors. The contribution of these polymorphisms to the cancer risk and prognosis of gastrointestinal tumors are reviewed in this paper.

Proteolytic action of kallikrein-related peptidase 7 produces unique active matrix metalloproteinase-9 lacking the C-terminal hemopexin domains

The gelatinases, matrix metalloproteinase (MMP)-9 and -2, are produced as latent, inactive enzymes that can be proteolytically activated by a number of proteases. In many normal and pathological conditions, where the expression of MMPs is deregulated, changes in the expression of other proteases have also been reported. Human kallikrein-related peptidase 7 (KLK7), a chymotryptic-like serine protease, is overexpressed in many different types of neoplastic conditions, which have also been shown to express high levels of both MMP-9 and -2. Since the activation of MMPs by KLK7 has never been examined, we sought to determine whether KLK7 can activate these MMPs. To test this hypothesis KLK7 was incubated with the recombinant MMPs and the products of the reaction were analyzed for their activity. Incubation of proMMP-9 with KLK7 resulted in the production of a novel truncated, active MMP-9 lacking the C-terminal hemopexin domains. In contrast, KLK7 degraded, but did not activate, proMMP-2. The novel activation of proMMP-9 by KLK7 was further confirmed using conditioned medium prepared from an MMP-9-expressing cell line, MDA-MMP-9. Our results clearly establish that KLK7 activates proMMP-9 to produce a novel truncated, active MMP-9 product not generated by other proteases. These findings suggest that KLK7 may play an important role in the activation of MMP-9 in tumors that express high levels of both these proteases and the resulting truncated MMP may possess altered substrate specificities compared with full-length MMP-9 activated by other proteases.

Stat3 and MMP7 contribute to pancreatic ductal adenocarcinoma initiation and progression

Chronic pancreatitis is a well-known risk factor for pancreatic ductal adenocarcinoma (PDA) development in humans, and inflammation promotes PDA initiation and progression in mouse models of the disease. However, the mechanistic link between inflammatory damage and PDA initiation is unclear. Using a Kras-driven mouse model of PDA, we establish that the inflammatory mediator Stat3 is a critical component of spontaneous and pancreatitis-accelerated PDA precursor formation and supports cell proliferation, metaplasia-associated inflammation, and MMP7 expression during neoplastic development. Furthermore, we show that Stat3 signaling enforces MMP7 expression in PDA cells and that MMP7 deletion limits tumor size and metastasis in mice. Finally, we demonstrate that serum MMP7 level in human patients with PDA correlated with metastatic disease and survival.

Tissue biomarkers for prognosis in pancreatic ductal adenocarcinoma: a systematic review and meta-analysis

PURPOSE

The management of pancreatic ductal adenocarcinoma (PDAC) continues to present a great challenge particularly with regard to prediction of outcome following pancreaticoduodenectomy. Molecular markers have been extensively investigated by numerous groups with the aim of enhancing prognostication; however, despite hundreds of studies that have sought to assess the potential prognostic value of molecular markers in predicting the clinical course following resection of PDAC, at this time, no molecular marker assay forms part of recommended clinical practice.

EXPERIMENTAL DESIGN

We conducted a systematic review and meta-analysis of the published literature for immunohistochemistry-based biomarkers of PDAC outcome. A dual search strategy was applied to the PubMed database on January 6, 2010, to identify cohort studies that reported associations between immunohistochemical biomarker expression and survival outcomes in PDAC, and conformed to the REMARK (REporting recommendations for tumor MARKer prognostic studies) criteria.

RESULTS

A total of 103 distinct proteins met all inclusion criteria. Promising markers that emerged for the prediction of overall survival included BAX (HR = 0.31, 95% CI: 0.71-0.56), Bcl-2 (HR = 0.41, 95% CI: 0.27-0.63), survivin (HR = 0.46, 95% CI: 0.29-0.73), Ki-67: (HR = 2.42, 95% CI: 1.87-3.14), COX-2 (HR = 1.39, 95% CI: 1.13-1.71), E-cadherin (HR = 1.80, 95% CI: 1.33-2.42), and S100 calcium-binding proteins, in particular S100A2 (HR = 3.23, 95% CI: 1.58-6.62).

CONCLUSIONS

We noted that that there was incomplete adherence to the REMARK guidelines with inadequate methodology reporting as well as failure to perform multivariate analysis. Addressing the persistent incomplete adoption of these criteria may eventually result in the incorporation of molecular marker assessment within PDAC management algorithms.

Ukrain affects pancreas cancer cell phenotype in vitro by targeting MMP-9 and intra-/extracellular SPARC expression

BACKGROUND/AIMS

We investigated whether the anticancer drug Ukrain (UK) is able to modulate the expression of some of the key markers of tumor progression in pancreatic cell carcinoma, in order to assess its potential therapeutic effect.

METHODS

Three cell lines (HPAF-II, PL45, HPAC) were treated with UK (5, 10 and 20 μM) for 48 h, or left untreated. Secreted protein acidic and rich in cysteine (SPARC) mRNA levels were assessed by real-time PCR. Matrix metalloproteinases (MMP)-2 and -9 activity was analyzed by SDS zymography; SPARC protein levels in cell lysates and supernatants were determined by Western blot. Cell cycle was determined by flow cytometric analysis, and invasion by matrigel invasion assay.

RESULTS

UK down-regulated MMP-2 and MMP-9, suggesting that UK may decrease pancreatic cancer cell invasion, as confirmed by the matrigel invasion assay. SPARC protein down-regulation in supernatants points to an inhibition by UK of extracellular matrix remodeling in the tumor microenvironment. At the same time, SPARC mRNA and cellular protein level up-regulation suggests that UK can affect cell proliferation by cell cycle inhibition, showing a cell cycle G2/M arrest in UK-treated cells.

CONCLUSION

Our results suggest that UK modulates two major aspects involved in tumorigenesis of pancreatic cancer cells, such as extracellular matrix remodeling and cell proliferation.

MMP-1 is a (pre-)invasive factor in Barrett-associated esophageal adenocarcinomas and is associated with positive lymph node status

Background

Esophageal adenocarcinomas (EACs) arise due to gastroesophageal reflux, with Barrett's esophagus (BE) regarded as precancerous lesion. Matrix metalloproteinases (MMPs) might play a role during the multistep carcinogenetic process.

Methods

Expression of MMP-1 and -13 was analyzed in esophageal cancer (n = 41 EAC with BE, n = 19 EAC without BE, and n = 10 esophageal squamous-cell carcinomas, ESCC), furthermore in BE without intraepithelial neoplasia (IN) (n = 18), and the cell line OE-33. MMP-1 was co-labelled with Ki-67 (proliferation), Cdx-2 (marker for intestinal metaplasia, BE) and analyzed on mRNA level. MMP-1 staining results were correlated with clinicopatholocical parameters.

Results

On protein level, MMP-1 expression was found in 39 of 41 (95%) EAC with BE, in 19 of 19 (100%) EAC without BE, in 6 of 10 (60%) ESCC, and in 10 of 18 (56%) BE without IN. No expression of MMP-13 was found in these specimens. Quantification showed 48% MMP-1 positive cells in EAC with BE, compared to 35% in adjacent BE (p < 0.05), 44% in EAC without BE, 32% in ESCC, and 4% in BE without IN. Immunofluorescence double staining experiments revealed increased MMP-1 expressing in proliferating cells (MMP-1+/Ki-67+) (r = 0.943 for BE and r = 0.811 for EAC). On mRNA-level, expression of MMP-1 was significantly higher in EAC compared to BE (p = 0.01) and confirmed immunohistochemical staining results. High MMP-1 levels were associated with lymph node metastases but not with poorer survival (p = 0.307).

Conclusions

Our findings suggest that MMP-1 plays a role as preinvasive factor in BE-associated EAC. Expression of MMP-1 in proliferating BE and EAC cells suggest malignant proliferation following the clonal expansion model.

Catecholamine up-regulates MMP-7 expression by activating AP-1 and STAT3 in gastric cancer

BACKGROUND

Stress, anxiety and depression can cause complex physiological and neuroendocrine changes, resulting in increased level of stress related hormone catecholamine, which may constitute a primary mechanism by which physiological factors impact gene expression in tumors. In the present study, we investigated the effects of catecholamine stimulation on MMP-7 expression in gastric cancer cells and elucidated the molecular mechanisms of the up-regulation of MMP-7 level by catecholamine through an adrenergic signaling pathway.

RESULTS

Increased MMP-7 expression was identified at both mRNA and protein levels in the gastric cancer cells in response to isoproterenol stimulation. β2-AR antigonist effectively abrogated isoproterenol-induced MMP-7 expression. The activation of STAT3 and AP-1 was prominently induced by isoproterenol stimulation and AP-1 displayed a greater efficacy than STAT3 in isoproterenol-induced MMP-7 expression. Mutagenesis of three STAT3 binding sites in MMP-7 promoter failed to repress the transactivation of MMP-7 promoter and silencing STAT3 expression was not effective in preventing isoproterenol-induced MMP-7 expression. However, isoproterenol-induced MMP-7 promoter activities were completely disappeared when the AP-1 site was mutated. STAT3 and c-Jun could physically interact and bind to the AP-1 site, implicating that the interplay of both transcriptional factors on the AP-1 site is responsible for isoproterenol-stimulated MMP-7 expression in gastric cancer cells. The expression of MMP-7 in gastric cancer tissues was found to be at the site where β2-AR was overexpressed and the levels of MMP-7 and β2-AR were the highest in the metastatic locus of gastric cancer.

CONCLUSIONS

Up-regulation of MMP-7 expression through β2-AR-mediated signaling pathway is involved in invasion and metastasis of gastric cancer.

MMP-7 as a prognostic marker in colorectal cancer

Matrix metalloproteinase-7 is capable of degrading many extracellular matrix proteins and cellular adhesions. In many malignancies, it is overexpressed, and it plays a role in cancer progression by enhancing tumor invasion and thereby metastatic potential. The purpose of this study was to evaluate the association between MMP-7 tissue expression and prognosis in colorectal cancer. From 623 patients who underwent surgery for colorectal cancer, surgical specimens were collected into tissue array blocks and stained by immunohistochemistry for MMP-7. Specimens from 545 patients were suitable for analysis. In specimens from 105 patients (19.3%), MMP-7 scored as high; in 103 (18.9%), as moderate; and in 134 (24.9%), as mild. In 203 cases (37.2%), immunoreactivity was negative. A significant correlation appeared between MMP-7 immunoexpression and tumor differentiation. High MMP-7 positivity associated with poor prognosis during a 5-year follow-up. During longer follow-up, the differences in survival between groups disappeared. MMP-7 is a potential target for tumor therapy, which should be evaluated in clinical trials.

MicroRNA-203 expression as a new prognostic marker of pancreatic adenocarcinoma

BACKGROUND

Detection of aberrant microRNA (miR) expression may contribute to diagnosis and prognosis of various cancers. The aim of this study is to evaluate the correlation between miR-203 expression and prognosis of patients with pancreatic adenocarcinoma after curative resection.

METHODS

A total of 113 formalin-fixed paraffin-embedded tissue samples of pancreatic adenocarcinoma, 20 samples of chronic pancreatitis, and 8 samples of normal pancreas were obtained. We investigated the association of miR-203 expression measured by quantitative reverse-transcription polymerase chain reaction assays with clinicopathological parameters and survival times.

RESULTS

miR-203 was overexpressed in pancreatic adenocarcinoma samples compared with chronic pancreatitis (P < 0.001) and normal pancreas (P = 0.001) samples. An association between miR-203 expression and clinicopathological factors of pancreatic adenocarcinoma was not observed. On univariate analysis, the high-miR-203 group and the subgroup (20%) of cases with the highest miR-203 overexpression had significantly shorter survival time (P = 0.048 and P = 0.024, respectively). Multivariate analysis revealed that miR-203 expression was an independent predictor of poor prognosis in cases with no residual tumor (relative risk 2.298, P = 0.027).

CONCLUSIONS

miR-203 expression is a new prognostic marker in pancreatic adenocarcinoma patients.

Matrix metalloproteinase (MMP)-7 in salivary gland cancer

INTRODUCTION

High levels of certain matrix metalloproteinases (MMPs) have been detected in various human cancers. The purpose of this study was to analyze the expression of MMP-7 in salivary gland cancer (SGC) by immunohistochemistry and to associate the results with the clinical data and the 10-year survival of the SGC patients.

MATERIAL AND METHODS

Immunohistochemistry for MMP-7 was performed in a series of 107 paraffin-embedded sections of SGC. The samples represent the entire SGC population in Finland from 1991-1996. Mortality follow-up ended December 31, 2006.

RESULTS

The study population of 107 patients consisted of 47 male and 60 female subjects, ranging in age at the time of diagnosis between 23 and 90 years. The minimum follow-up time was 10.6 years and the maximum 15.9 years. By age-adjusted analysis lower staining intensity was associated with worse overall survival of patients with acinic cell carcinoma (p = 0.047, HR 6.5, 95% Cl 1.0-41.7) and in mucoepidermoid carcinoma (p = 0.010, HR 9.3, 95% CI 1.7-50.0). Low staining intensity was also associated with worse disease-specific survival of patients with acinic cell carcinoma (0-1 vs. 2-3; p = 0.047, HR 13.7, 1.0-200.0). VCI Ki-67 was an important prognostic factor for survival of the entire data set (p < 0.0001, HR 4.7, 95% Cl 2.3-9.8).

CONCLUSIONS

MMP-7 is associated with the prognosis of patients with acinic cell and mucoepidermoid carcinoma.

Molecular mechanism of pancreatic cancer--understanding proliferation, invasion, and metastasis

INTRODUCTION

The purpose of this review is to highlight the molecular mechanisms leading to the development and progression of pancreatic ductal adenocarcinoma (PDAC) with particular emphasis on tumor cell proliferation, local invasion, and metastasis. Recent advances in the field of PDAC biology have shed light on the molecular events that trigger PDAC initiation and maintenance.

RESULTS

It is now clear that apart from the genetic alterations within the tumor cells, interactions of the tumor with its environment are necessary for proliferation and invasion. Interestingly, a number of developmental signaling pathways are reactivated in PDAC. Progress has also been made in the understanding of the molecular events that govern the process of metastasis.

CONCLUSION

Although our understanding of the mechanisms underlying PDAC pathobiology are more advanced than ever, little progress has been made in the clinical treatment of PDAC, and successful bench-to-bedside transfer of knowledge to boost new treatment options is still unsatisfying.

MMP-7 overexpression is an independent prognostic marker in gastric cancer

To enable cancer to invade and to metastasize, the surrounding stroma must be degraded. Matrix metalloproteinase-7 (MMP-7) is capable of degrading many extracellular matrix proteins and cellular adhesions, is overexpressed in many malignancies, and plays a role in tumour progression. The purpose of this study was to evaluate the association between MMP-7 tissue expression and patients' prognosis in gastric cancer. From 264 patients who underwent surgery for gastric cancer, surgical specimens were collected on tissue array blocks and stained by immunohistochemistry for MMP-7. In 27 (10.2%) of the specimens, immunopositivity was found as high, in 50 (18.9%) as moderate and in 51 (19.3%) as weak. In 136 cases (51.5%), the immunopositivity was negative. A statistically significant correlation appeared between high MMP-7 expression and poor survival. In conclusion, our results suggest that MMP-7 expression may prove helpful in evaluating gastric cancer prognosis.

S100A4 mRNA is a diagnostic and prognostic marker in pancreatic carcinoma

OBJECTIVE

The aim of this study is to evaluate the clinical significance of S100A4 mRNA expression in pancreatic cancer.

MATERIALS AND METHODS

We obtained invasive ductal carcinoma (IDC) cells from ten lesions, intraductal papillary mucinous neoplasm (IPMN) cells from 20 lesions, and normal ductal cells from 20 normal pancreatic tissues by laser microdissection of frozen tissues. S100A4 expression was examined in the microdissected cells and in formalin-fixed paraffin-embedded (FFPE) samples of 87 pancreatic cancers by quantitative reverse transcription-polymerase chain reaction.

RESULTS

IDC cells expressed higher levels of S100A4 than IPMN cells (P = 0.002) and normal ductal cells (P < 0.001), although the difference between IPMN cells and normal ductal cells was not statistically significant (P = 0.070). Analysis of FFPE samples revealed that high S100A4 expression was significantly associated with a shorter overall survival (P = 0.023). In immunohistochemical analysis, the extent of S100A4 mRNA expression was significantly correlated with the expression of S100A4 protein (P = 0.028).

CONCLUSION

S100A4 could be a marker for malignancy in pancreatic tumors and for poor prognosis in patients with pancreatic cancer.

The role of MMP7 and its cross-talk with the FAS/FASL system during the acquisition of chemoresistance to oxaliplatin

Background

The efficacy of oxaliplatin in cancer chemotherapy is limited by the development of drug resistance. MMP7 has been related to the loss of tumor cell response to cytotoxic agents although the exact mechanism is not fully understood. Moreover, MMP7 is an independent prognosis factor for survival in patients with colorectal cancer. The aim of the present study was to analyze the role of MMP7 and its cross-talk with the Fas/FasL system during the acquisition of oxaliplatin resistance in colon cancer cells.

Principal Findings

For this purpose we have developed three different oxaliplatin-resistant cell lines (RHT29, RHCT116 p53^+/+, RHCT116 p53^−/−) from the parental HT29, HCT116 p53^+/+ and HCT116 p53^−/− colon cancer cells. MMP7 basal expression was higher in the resistant compared to the parental cell lines. MMP7 was also upregulated by oxaliplatin in both HT29 (p53 mutant) and RHCT116 p53^−/− but not in the RHCT116 p53^+/+. Inhibition of MMP by 1,10-phenantroline monohydrate or siRNA of MMP7 restores cell sensitivity to oxaliplatin-induced apoptosis in both HT29 and RHCT116 p53^−/− but not in the RHCT116 p53^+/+. Some of these effects are caused by alterations in Fas receptor. Fas is upregulated by oxaliplatin in colon cancer cells, however the RHT29 cells treated with oxaliplatin showed a 3.8-fold lower Fas expression at the cell surface than the HT29 cells. Decrease of Fas at the plasma membrane seems to be caused by MMP7 since its inhibition restores Fas levels. Moreover, functional analysis of Fas demonstrates that this receptor was less potent in inducing apoptosis in RHT29 cells and that its activation induces MAPK signaling in resistant cells.

Conclusions

Taking together, these results suggest that MMP7 is related to the acquisition of oxaliplatin-resistance and that its inhibition restores drug sensitivity by increasing Fas receptor. Furthermore, Fas undergoes a change in its functionality in oxaliplatin-resistant cells inducing survival pathways instead of apoptotic signals.

Depletion of cell surface CD44 in nonmelanoma skin tumours is associated with increased expression of matrix metalloproteinase 7

BACKGROUND

Expression of matrix metalloproteinase (MMP)-7 and MMP-9 is low in the normal epidermis and is induced by physiological processes such as wound healing, but also malignant transformation of epidermal cells. The activity of both MMPs has been associated with the hyaluronan (HA) receptor CD44. We previously reported that the levels of CD44 and HA differ between the two types of epidermal tumours, basal (BCC) and squamous cell carcinoma (SCC), as well as between different grades of SCC.

OBJECTIVES

To investigate if the immunostaining patterns of MMP-7 and MMP-9 correlate to those of CD44 and HA in BCC and SCC.

METHODS

Paraffin sections from 71 BCCs, 21 in situ SCCs and 27 SCCs were immunostained for MMP-7 and -9.

RESULTS

Positive immunostaining for MMP-7 and MMP-9 was found in tumour cells of both BCC and SCC, while the staining intensity tended to be stronger in SCC. The staining intensity of MMP-7 was inversely correlated with that of CD44 in both tumour types. In well-differentiated SCC, the intensity of MMP-7 was generally weak, while CD44 staining was strong and homogeneously distributed. In poorly differentiated SCC, an increase in MMP-7 was seen, and the staining intensity of CD44 became weak and was locally absent. No correlation was seen between MMP-9 and CD44 or either of the two MMPs and HA.

CONCLUSIONS

Our results show that in nonmelanoma skin tumours MMP-7 and -9 are present in the tumour cells, and suggest a link between MMP-7 activity and the depletion of cell surface CD44.

Genetic polymorphisms in the MMP-7 gene and breast cancer survival

Matrix metalloproteinase-7 (MMP-7) is a small secreted proteolytic enzyme with broad substrate specificity. Its expression has been shown to be associated with tumor invasion, metastasis and survival for a variety of cancers. We systematically evaluated single nucleotide polymorphisms (SNPs) in MMP-7 in relation to breast cancer survival in a large follow-up study. Included were 1,079 breast cancer cases that were recruited from 1996 to 1998 and followed for a median of 7.1 years as part of the Shanghai Breast Cancer Study (SBCS). Eleven SNPs, including 2 known functional promoter SNPs, were analyzed using the Affymetrix Targeted Genotyping System. Associations with survival were evaluated by Cox proportional hazards regression and Kaplan-Meier functions. Statistically significant associations with disease-free and/or overall survival (OS) were found for 5 polymorphisms; these associations were explained primarily by 2 SNPs (rs11568818 and rs11225297) that were in high linkage disequilibrium (LD) with the others. Patients homozygous for the rs11568818 rare allele (G) had a significantly worse prognosis (OS HR: 6.7, 95% CI: 2.4-18.6) than patients homozygous for the common allele (A). Significantly improved survival was seen for patients with the rs11225297 T allele, and this association occurred in a dose-response manner; patients with AT (OS HR: 0.7, 95% CI: 0.5-0.9) and TT (OS HR: 0.3, 95% CI: 0.1-0.8) fared better than patients with AA (p-value for trend: 0.001). Thus, common MMP-7 genetic polymorphisms were found to be significant determinants of survival among Chinese women with breast cancer.

[Analysis of TIMP-1, TIMP-2 and TIMP-3 expression as a prognostic factor of laryngeal cancer progression]

INTRODUCTION

Tissue inhibitors of matrix metalloproteinases (TIMPs) are natural regulator of activity of matrix metalloproteinases, that are responsible for ECM degradation. TIMPs have been identified in various carcinomas and in most of them dependence between TIMPs and clinical course of the disease have been observed.

AIM

Of the research was to evaluate expression of TIMP-1, TIMP-2 and TIMP-3 in laryngeal cancer and to asses the prognostic significance of these factors.

MATERIAL AND METHOD

104 patients with laryngeal cancer, that underwent surgical treatment were included in the study. Only cases with at least a 5-year follow-up were included. Immunohistochemical studies were performed on formalin fixed, paraffin embedded sections by using monoclonal antibodies against TIMP-1, -2 and -3 antigens and ABC detection system. Results. TIMPs expression was cytoplasmatic, mainly in cancer cells, but also in some stromal cells. TIMP-1 and TIMP-2 correlated with grading (TIMP-1 p = 0,05; TIMP-2 p = 0,001). There was an association between TIMP-2 and TIMP-3 expression and tumor size (TIMP-2 p = 0,037; TIMP-3 p = 0,022). TIMP-3 expression correlated with clinical stage of the disease (p = 0,037). There was an association between TIMP-2 expression and nodal recurrence (p = 0,05). Both overall and disease-free survival were shorter in cases with positive TIMP-2 expression (p = 0,049).

CONCLUSIONS

Our results demonstrate that there is an association between TIMPs expression and clinicopathological features of laryngeal cancer. Moreover TIMP-2 could be an important marker in prognosis of laryngeal cancer patients.

Degradation of soluble VEGF receptor-1 by MMP-7 allows VEGF access to endothelial cells

Vascular endothelial growth factor (VEGF) signaling in endothelial cells serves a critical role in physiologic and pathologic angiogenesis. Endothelial cells secrete soluble VEGF receptor-1 (sVEGFR-1/sFlt-1), an endogenous VEGF inhibitor that sequesters VEGF and blocks its access to VEGF receptors. This raises the question of how VEGF passes through this endogenous VEGF trap to reach its membrane receptors on endothelial cells, a step required for VEGF-driven angiogenesis. Here, we show that matrix metalloproteinase-7 (MMP-7) degrades human sVEGFR-1, which increases VEGF bioavailability around the endothelial cells. Using a tube formation assay, migration assay, and coimmunoprecipitation assay with human umbilical vein endothelial cells (HUVECs), we show that the degradation of sVEGFR-1 by MMP-7 liberates the VEGF(165) isoform from sVEGFR-1. The presence of MMP-7 abrogates the inhibitory effect of sVEGFR-1 on VEGF-induced phosphorylation of VEGF receptor-2 on HUVECs. These data suggest that VEGF escapes the sequestration by endothelial sVEGFR-1 and promotes angiogenesis in the presence of MMP-7.

Matrilysin (MMP-7) is a novel broadly expressed tumor antigen recognized by antigen-specific T cells

PURPOSE

A prerequisite for the development of vaccination strategies is the identification and characterization of relevant tumor-associated antigen. Using microarray and reverse transcription-PCR analysis, we found matrix metalloproteinase (MMP)-7 to be extensively up-regulated in renal cell carcinomas and expressed in a broad variety of malignant cells. MMP-7 can promote cancer invasion and angiogenesis by proteolytic cleavage of extracellular matrix and basement membrane proteins, thus making it a promising target in the context of immunotherapies.

EXPERIMENTAL DESIGN

To analyze the possible use of MMP-7 as a tumor-associated antigen, specific CTLs were induced using monocyte-derived dendritic cells electroporated with MMP-7-mRNA. In addition, to better characterize the fine specificity of these CTLs, MMP-7 MHC class I ligands were isolated and characterized in renal cell carcinoma tissue, which overexpressed MMP-7, by mass spectrometry-based peptide sequencing. Using this approach, we identified a novel HLA-A3-binding antigenic MMP-7 peptide. CTLs generated from healthy donors by in vitro priming with dendritic cells, pulsed with the novel peptide, were used as effectors in (51)Cr-release assays.

RESULTS

The induced CTLs elicited an antigen-specific and HLA-restricted cytolytic activity against tumor cells endogenously expressing the MMP-7 protein. Furthermore, we were able to induce MMP-7-specific CTLs using peripheral blood mononuclear cells from a patient with acute lymphoblastic leukemia capable of recognizing the autologous leukemic blasts while sparing nonmalignant cells.

CONCLUSIONS

Our study describes the identification of a novel broadly expressed T-cell epitope derived from the MMP-7 protein that represents an interesting candidate to be applied in immunotherapies of human malignancies targeting both tumor cells and neovascularization.

Proximity-activated nanoparticles: in vitro performance of specific structural modification by enzymatic cleavage

The development and in vitro performance of a modular nanoscale system capable of specific structural modification by enzymatic activity is described in this work. Due to its small physical size and adaptable characteristics, this system has the potential for utilization in targeted delivery systems and biosensing. Nanoparticle probes were synthesized containing two distinct fluorescent species including a quantum dot base particle and fluorescently labeled cleavable peptide substrate. Activity of these probes was monitored by gel electrophoresis with quantitative cleavage measurements made by fluorometric analysis. The model proximity-activated nanoparticles studied here exhibit significant susceptibility to cleavage by matrix metalloprotease-7 (MMP-7) at physiologically relevant concentrations, with nearly complete cleavage of available substrate molecules after 24 hours. This response is specific to MMP-7 enzyme activity, as cleavage is completely inhibited with the addition of EDTA. Utilization of enzyme-specific modification is a sensitive approach with broad applications for targeted therapeutics and biosensing. The versatility of this nanoparticle system is highlighted in its modular design, as it has the capability to integrate characteristics for detection, biosensing, targeting, and payload delivery into a single, multifunctional nanoparticle structure.

Expression of matrix metalloproteinase 7 is an unfavorable postoperative prognostic factor in cholangiocarcinoma of the perihilar, hilar, and extrahepatic bile ducts

Cholangiocarcinoma of the perihilar, hilar, and extrahepatic bile ducts (collectively referred to as the large bile ducts) is an intractable disease, and a papillary phenotype and well-differentiated histologic grade have been proposed as indicators of a favorable prognosis after surgical resection. In this study, we examined the significance of matrix metalloproteinases (MMPs) in cholangiocarcinoma with respect to clinicopathologic features. We subjected 66 surgically resected specimens of cholangiocarcinoma of the large bile ducts to clinicopathologic examination, including postoperative survival, papillary phenotype, and immunohistochemical expression of MMP-2,-7, -9, and membrane type 1 MMP (MT1-MP). Nonneoplastic biliary epithelium did not express these 4 MMPs, whereas cholangiocarcinoma frequently expressed MMP-2 (33.9%), -7 (75.8%), -9 (47.5%), and MT1-MMP (54.5%). In particular, conventional (nonpapillary) cholangiocarcinoma expressed MMP-7 and MT1-MMP more frequently than papillary cholangiocarcinoma. The expression of MMP-7 and MT1-MMP significantly correlated with the nonpapillary phenotype, poorly differentiated histologic grade, perineural invasion, and advanced TNM stage. In contrast, the expression of MMP-2 and -9 was not associated with any of the clinicopathologic features. Univariate analysis of disease-specific survival revealed that a papillary phenotype and expression of MMP-7 were prognostic factors of cholangiocarcinoma, in addition to TNM stage, poorly differentiated histologic grade, perineural invasion, and microscopic margin status. Multivariate analysis showed only TNM stage to be an independent prognostic factor. Expression of MMP-7 in cholangiocarcinoma is an unfavorable postoperative prognostic factor of cholangiocarcinoma arising from the large bile ducts. Underexpression of MMPs in papillary cholangiocarcinoma might be associated with a favorable prognosis.

Expression of Wnt5a and its downstream effector beta-catenin in uveal melanoma

Upregulation of the Wnt5a pathway has been reported in some cutaneous melanomas but its role in uveal melanoma has not been assessed. We thus sought to determine whether activation of the Wnt-signalling pathway occurred in uveal melanoma through upregulation of some of the key downstream effectors, and whether expression of these components was associated with tumour characteristics and clinical outcome. Expression of Wnt5a, MMP7, and beta-catenin was determined in 40 primary uveal melanomas by immunohistochemistry and correlated with patient prognosis. The proportion of cells immunoreactive for Wnt5a, MMP7, and beta-catenin was higher in tumours from patients with shorter survival and this difference was statistically significant for Wnt5a (P<0.01) and beta-catenin (P=0.02). These data show for the first time activation of the Wnt/beta-catenin-signalling pathway in uveal melanoma and suggest that components of this pathway might be useful prognostic markers as well as attractive therapeutic targets to treat this disease.

Identification of pro-MMP-7 as a serum marker for renal cell carcinoma by use of proteomic analysis

BACKGROUND

No validated renal cell carcinoma (RCC) marker is known for detection of asymptomatic disease in selected populations or for prognostic purposes or treatment monitoring. We identified immunogenic proteins as tumor markers for RCC by combining conventional proteome analysis with serological screening, and we investigated the diagnostic clinical value of such markers in serum.

METHODS

We studied the immunogenic protein expression profile of CAL 54, a human RCC cell line, by 2-dimensional electrophoresis combined with immunoblotting using sera from healthy donors compared with RCC patients. We developed a homogeneous, fluorescent, dual-monoclonal immunoassay for metalloproteinase 7 (MMP-7) and used it to measure MMP-7 in sera from 30 healthy donors, 30 RCC patients, and 40 control patients.

RESULTS

Pro-MMP-7 (29 kDa; pI 7.7) in the CAL 54 cell line secretome was an immunogenic protein reactive with RCC patient sera but not with control sera. The concentrations of pro-MMP-7 were increased (P <0.0001) in sera of RCC patients (median 7.56 microg/L; range 3.12-30.5 microg/L) compared with healthy controls (median 2.13 microg/L; range 0.17-3.5 microg/L). Serum pro-MMP-7 had a sensitivity of 93% (95% CI 78%-99%) at a specificity of 75% (59%-87%) for RCC in the samples tested.

CONCLUSION

Proteomics technology combined with serology led to the identification of serum pro-MMP-7 as a marker of RCC and represents a powerful tool in searching for candidate proteins as biomarkers.

Increased expression of matrix metalloproteinases-21 and -26 and TIMP-4 in pancreatic adenocarcinoma

Pancreatic adenocarcinoma is known for early aggressive local invasion, high metastatic potential, and a low 5-year survival rate. Matrix metalloproteinases (MMPs) play important roles in tumor growth and invasion. Earlier studies on pancreatic cancer have found increased expression of certain MMPs to correlate with poorer prognosis, short survival time or presence of metastases. We studied the expression of MMP-21, -26, and tissue inhibitor of matrix metalloproteinases (TIMP)-4 in 50 tissue samples, including 25 adenocarcinomas, seven other malignant pancreatic tumors, and 18 control samples of non-neoplastic pancreatic tissue with immunohistochemistry. The regulation of MMP-21, -26, and TIMP-4 mRNAs by cytokines was studied with RT-PCR in pancreatic cancer cell lines PANC-1, BxPC-3, and AsPC-1. MMP-21, -26, and TIMP-4 were detected in cancer cells in 64, 40, and 60% of tumors, respectively. MMP-21 expressed in well-differentiated cancer cells and occasional fibroblasts, like TIMP-4, tended to diminish in intensity from grade I to grade III tumors. Patients with metastatic lymph nodes had increased expression of MMP-26 in actual tumor samples. All cultured cancer cell lines expressed MMP-21 basally at low levels, and presence of the protein was confirmed immunohistochemically in cultured cells. MMP-21 expression was induced by epidermal growth factor (EGF) in PANC-1 cells. MMP-26 was neither expressed basally nor induced by tumor necrosis factor alpha, transforming growth factor beta-1 (TGFbeta1), EGF, or interferon gamma. Basal TIMP-4 expression was lowest in the poorly differentiated cancer cell line PANC-1 compared to better-differentiated BxPC-3 and AsPC-1 cells. TIMP-4 expression was induced by TGFbeta1 in PANC-1 cells and by EGF in BxPC-3 cells. Our findings suggest that MMP-21 is not a marker of invasiveness, but rather of differentiation, in pancreatic cancer and it may be upregulated by EGF. The putative role of MMP-26 as a marker of metastases warrants further studies. Unlike other TIMPs, TIMP-4 was not upregulated in relation to aggressiveness of pancreatic cancer.

Stromal biology of pancreatic cancer

The genetic paradigm of cancer, focused largely on sequential molecular aberrations and associated biological impact in the neoplastic cell compartment of malignant tumors, has dominated our view of cancer pathogenesis. For the most part, this conceptualization has overlooked the dynamic and complex contributions of the surrounding microenvironment comprised of non-tumor cells (stroma) that may resist, react to, and/or foster tumor development. Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease in which a prominent tumor stroma compartment is a defining characteristic. Indeed, the bulk of PDAC tumor volume consists of non-neoplastic fibroblastic, vascular, and inflammatory cells surrounded by immense quantities of extracellular matrix, far exceeding that found in most other tumor types. Remarkably, little is known about the composition and physiology of the PDAC tumor microenvironment, in particular, the role of stroma in tumor initiation and progression. This review attempts to define key challenges, opportunities and state-of-knowledge relating to the PDAC microenvironment research with an emphasis on how inflammatory processes and key cancer pathways may shape the ontogeny of the tumor stroma. Such knowledge may be used to understand the evolution and biology of this lethal cancer and may convert these insights into new points of therapeutic intervention.

MMP-7 (matrilysin) expression in human brain tumors

Matrix metalloproteinases (MMP) which degrades protein components of the extra-cellular matrix and basement membrane seems to be largely involved in cancer invasiveness. MMP proteolitic activity essentially comes from stromal cells but matrilysin (MMP-7) is produced by the tumor itself. Thus, MMP-7 is investigated to address the particular invasive behavior of human glioma. Both MMP-7 mRNA and protein were clearly identified in human glioma. MMP-7 mRNA expression was highly variable within our glioma population. When analyzing MMP-7 mRNA expression in different primary brain tumors, we found highly variable levels of expression not related to their invasive behavior. In successive biopsies obtained in the same patients with glioblastoma, MMP-7 mRNA was quantified and appeared variable, but intra-individual variations were lower than inter-individual differences. With a xenograft model of U87 human tumors in RAG2/gamma(c) immune-deficient mice, the strict tumor origin of MMP-7 was shown. Additionally, MMP-7 expression by U87 cells which is low in culture was stimulated by these cells while forming tumors and the level of expression was higher when the tumor cells were implanted within the brain. These data provide some consistent information about cross-talk occurring between the tumor and the surrounding stroma to regulate MMP-7 expression.

Early detection and staging of adenocarcinoma of the pancreas

Early diagnosis is likely to improve the outcome and survival in patients who have pancreatic cancer. The sensitivity and specificity of current screening methods, however, limit their applicability to individuals at high risk for developing pancreatic cancer. Further development of serum markers may lead to improved diagnostic accuracy and allow screening to be implemented more broadly. Proteomic profiling and evaluation of panels of markers hold particular promise for the future. This article provides a review of current methods and results for the early detection and staging of pancreatic cancer, and discusses some potential areas for future development.

Evaluation of matrix metalloproteinase 7 in plasma and pancreatic juice as a biomarker for pancreatic cancer

Differentiating between periampullary carcinoma and chronic pancreatitis with an inflammatory mass is difficult. Consequently, 6% to 9% of pancreatic resections for suspected carcinoma are done inappropriately for chronic pancreatitis. Here, we test if matrix metalloproteinase 7 (MMP-7), a secreted protease frequently expressed in pancreatic carcinoma, can be measured in plasma, pancreatic, and duodenal juice, and if it can distinguish between periampullary carcinoma and chronic pancreatitis. Ninety-four patients who underwent pancreatic surgery for a (peri)pancreatic neoplasm (n = 63) or chronic pancreatitis (n = 31) were analyzed. Median plasma MMP-7 levels were significantly higher in carcinoma (1.95 ng/mL; interquartile range, 0.81-3.22 ng/mL) compared with chronic pancreatitis and benign disease (0.83 ng/mL; interquartile range, 0.25-1.21 ng/mL; P < 0.01). MMP-7 levels in pancreatic juice were higher, although not significantly, in carcinoma (62 ng/mg protein; interquartile range, 18-241 ng/mg protein) compared with chronic pancreatitis and benign disease (23 ng/mg protein; interquartile range, 8.5-99 ng/mg protein; P = 0.17). MMP-7 levels in duodenal juice were universally low. At an arbitrary cutoff of 1.5 ng/mL in plasma, positive and negative predictive values were 83% and 57%, respectively, values comparable to those of today's most common pancreatic tumor marker, carbohydrate antigen 19-9 (CA19-9; 83% and 53%, respectively). Positive and negative likelihood ratios for plasma MMP-7 were 3.35 and 0.52, respectively. The area under the receiver operating characteristic curve for MMP-7 was 0.73 (95% confidence interval, 0.63-0.84) and for CA19-9, 0.75 (95% confidence interval, 0.64-0.85). Combined MMP-7 and CA19-9 assessment gave a positive predictive value of 100%. Thus, plasma MMP-7 levels discriminated between patients with carcinoma and those with chronic pancreatitis or benign disease. The diagnostic accuracy of plasma MMP-7 alone is not sufficient to determine treatment strategy in patients with a periampullary mass, but combined evaluation of plasma MMP-7 with CA19-9 and other markers may be clinically useful.

Epithelial MMP-2 Expression Correlates with Worse Prognosis in Pancreatic Cancer

OBJECTIVE

Matrix metalloproteinases (MMPs) degrade extracellular matrix and are involved in tumor invasion and metastasis in various cancers. In pancreatic cancer, MMP-2 expression is upregulated and correlates with tumor recurrence. The aim of this study was to evaluate the prognostic significance of MMP-2 in pancreatic ductal adenocarcinoma.

METHODS

MMP-2 expression was assessed by immunohistochemistry in 127 patients operated on at Helsinki University Hospital from 1974 to 1998, with expression interpreted separately in epithelial and stromal samples.

RESULTS

Epithelial MMP-2 expression was strong in 5%, moderate in 20%, weak in 25% and negative in 50% of the tumors, with high epithelial MMP-2 expression significantly associated in univariate survival analysis with advanced stage, poor grade and poor survival. Stromal MMP-2 expression was strong in 0%, moderate in 14%, weak in 70% and negative in 16% of the cases, and did not significantly correlate with patient survival.

CONCLUSION

Epithelial MMP-2 correlates with advanced tumor stage and grade, but is not an independent predictor of survival.

Intraductal papillary mucinous neoplasms of the pancreas: an analysis of protein expression and clinical features

BACKGROUND/PURPOSE

The molecular pathology of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas has not been well characterized, and there are no reliable markers to predict the presence of associated invasive carcinoma in patients with IPMNs. We investigated the clinicopathologic characteristics of 37 IPMNs and the immunohistochemical findings of these tumors to investigate the malignancy of IPMNs.

METHODS

Between May 1992 and September 2003, 37 patients with IPMNs, 24 with adenoma and 13 with carcinoma, underwent pancreatic resections at Sapporo Medical University Hospital, Japan. In tumor specimens from these patients, we immunohistochemically analyzed the expression of p53 protein, proliferating-cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), matrix metalloproteinase-7 (MMP-7), and E-cadherin. Clinical features and follow-up after resection were recorded.

RESULTS

Aberrant expression of the proteins examined was frequently observed. Namely, there were significant differences in the expression of MMP-7 according to clinicopathological characteristics. Positive expression of MMP-7 was found in all of nine patients with infiltrating ductal pancreatic adenocarcinoma (IDC) and in all of seven patients with invasive intraductal papillary mucinous adenocarcinoma (IC-IPMC); however, 33.3% of patients with noninvasive IPMA, 58.3% of patients with intraductal papillary mucinous adenoma (IPMA), and all normal pancreatic tissues were negative for MMP-7; differences which were statistically significant (P < 0.05).

CONCLUSIONS

Our current results indicate that MMP-7 may play a significant role in the progression of noninvasive to invasive IPMC.

Matrix metalloproteinases in cancer: comparison of known and novel aspects of their inhibition as a therapeutic approach

Matrix dissolution is a crucial step during tumor progression that converts a premalignant cell to an overtly malignant one. Main players in this step are the various matrix metalloproteinases (MMPs), which differ in substrate specificity and tissue distribution, and thereby also differ in presence and function during various stages of initial and systemic tumor spread. Accordingly, the inhibition of MMP synthesis and/or activity represents novel potential therapeutic strategies for the treatment of cancer patients. Considerable work has already been carried out on synthetic inhibitors of MMP activity, but with little or even adverse effects in recent clinical studies. The reasons may be inappropriate patient populations in too advanced tumor stages, or inappropriate enzymes as targets for inhibition. Upregulation of endogenous tissue inhibitors of MMP (TIMPs) also provided ambiguous results, since TIMPs possess biologic functions in addition to MMP inhibition, for example, TIMP-2 is a main player in the MMP-2 activation cascade. This may explain, at least in part, the adverse effects of TIMP application/upregulation. Other strategies have been sought in order to overcome these problems. These include the downregulation of MMP transcription by cytokines. However, the effects of cytokines (other than MMP inhibition) may also limit the use of this approach. Finally, empiric evidence for control and modulation of MMP transcription and/or activation by several naturally occurring substances, such as flavonoids, green tea polyphenols and curcumin, represent novel options for the control of MMP activity even in early tumor stages. Additionally, these substances have little or no toxic side effects and good bioavailability, and therefore their continuing analysis provides intriguing insight into tumor pathophysiology and possibly new therapeutic options.