Invasiveness and MMP expression in pancreatic carcinoma

Fluoroquinolones Suppress TGF-β and PMA-Induced MMP-9 Production in Cancer Cells: Implications in Repurposing Quinolone Antibiotics for Cancer Treatment

BACKGROUND

Fluoroquinolones (FQs) are potent antimicrobials with multiple effects on host cells and tissues. Although FQs can attenuate cancer invasion and metastasis, the underlying molecular mechanisms remain unclear. Matrix metalloproteinase-9 (MMP-9) has functional roles in tumor angiogenesis, invasion, and metastasis, and is associated with cancer progression and poor prognosis, suggesting that inhibitors of MMP-9 activity and transcription are prime candidates for cancer therapy. Despite numerous preclinical data supporting the use of MMP-9 inhibitors as anticancer drugs, the few available examples are not therapeutically useful due to low specificity and off-target effects. We examined the effects of FQs on MMP-9 production in cancer cells following transforming growth factor beta (TGF-β) and phorbol 12-myristate 13-acetate (PMA) stimulation.

EXPERIMENTAL APPROACHES

Using confluent cultures of HepG2 and A549 cells, the effects of FQs (ciprofloxacin, levofloxacin, clinafloxacin, gatifloxacin, and enrofloxacin) on TGF-β and PMA-induced MMP-9 mRNA expression and production were studied in RNA extracts and culture supernatants, respectively. FQs specifically abrogated TGF-β and PMA-induced MMP-9 levels and activity in a concentration and time-dependent manner, without affecting other MMPs or proteins involved in epithelial-mesenchymal transition. Additionally, FQs inhibited TGF-β and PMA-induced cell migration via p38 and cyclic AMP signaling pathways.

CONCLUSIONS AND IMPLICATIONS

Overall, we demonstrated that FQs inhibit cancer cell migration and invasion by downregulating MMP-9 expression and revealed the cellular mechanisms underlying their potential value in cancer treatment.

Biomarkers of tumor invasiveness in proteomics (Review)

Over the past two decades, quantitative proteomics has emerged as an important tool for deciphering the complex molecular events involved in cancers. The number of references involving studies on the cancer metastatic process has doubled since 2010, while the last 5 years have seen the development of novel technologies combining deep proteome coverage capabilities with quantitative consistency and accuracy. To highlight key findings within this huge amount of information, the present review identified a list of tumor invasive biomarkers based on both the literature and data collected on a biocollection of experimental cell lines, tumor models of increasing invasiveness and tumor samples from patients with colorectal or breast cancer. Crossing these different data sources led to 76 proteins of interest out of 1,245 mentioned in the literature. Information on these proteins can potentially be translated into clinical prospects, since they represent potential targets for the development and evaluation of innovative therapies, alone or in combination. Herein, a systematical review of the biology of each of these proteins, including their specific subcellular/extracellular or multiple localizations is presented. Finally, as an important advantage of quantitative proteomics is the ability to provide data on all these molecules simultaneously in cell pellets, body fluids or paraffin‑embedded sections of tumors/invaded tissues, the significance of some of their interconnections is discussed.

Novel potential biomarkers for pancreatic cancer - A systematic review

BACKGROUND

It is estimated that in developed countries the incidence rate of pancreatic cancer (PC) will continue to rise and by 2020 will be the second most fatal cancer. The mortality of PC patients closely parallels the incidence rate, as this malignancy remains asymptomatic until it reaches an advanced stage of disease. Thus, novel biochemical markers that improve the management of PC patients are necessary. The aim of the work that follows is to investigate whether selected inflammatory mediators might be used in the diagnosis of PC, with the aim of improving the prognosis for PC patients.

METHODS

We performed a thorough search for literature pertaining to our investigation via the MEDLINE/PubMed database.

RESULTS

It has been proved that certain inflammatory mediators might be involved in tumor progression, such as growth, proliferation, migration and angiogenesis of tumor cells. In the present review, we summarized and referred to a number of original papers concerning the clinical significance of selected cytokines and specific inflammatory proteins such as C-reactive protein, as well as of various matrix metalloproteinases and their tissue inhibitors, as potential biomarkers for PC in comparison to well-established tumor markers for this malignancy.

CONCLUSION

Presented proteins might be potential biomarkers in the diagnosis and progression of PC.

Beta 2-microglobulin regulates amyloid precursor-like protein 2 expression and the migration of pancreatic cancer cells

Beta 2-microglobulin (β₂m) is a component of the major histocompatibility complex (MHC) class I molecule, which presents tumor antigens to T lymphocytes to trigger cancer cell destruction. Notably, β₂m has been reported as persistently expressed, rather than down regulated, in some tumor types. For renal cell and oral squamous cell carcinomas, β₂m expression has been linked to increased migratory capabilities. The migratory ability of pancreatic cancer cells contributes to their metastatic tendencies and lethal nature. Therefore, in this study, we examined the impact of β₂m on pancreatic cancer cell migration. We found that β₂m protein is amply expressed in several human pancreatic cancer cell lines (S2-013, PANC-1, and MIA PaCa-2). Reducing β₂m expression by short interfering RNA (siRNA) transfection significantly slowed the migration of the PANC-1 and S2-013 cancer cell lines, but increased the migration of the MIA PaCa-2 cell line. The amyloid precursor-like protein 2 (APLP2) has been documented as contributing to pancreatic cancer cell migration, invasiveness, and metastasis. We have previously shown that β₂m/HLA class I/peptide complexes associate with APLP2 in S2-013 cells, and in this study we also detected their association in PANC-1 cells but not MIA PaCa-2 cells. In addition, siRNA down regulation of β₂m expression diminished the expression of APLP2 in S2-013 and PANC-1 but heightened the level of APLP2 in MIA PaCa-2 cells, consistent with our migration data and co-immunoprecipitation data. Thus, our findings indicate that β₂m regulates pancreatic cancer cell migration, and furthermore suggest that APLP2 is an intermediary in this process.

Expression of Matrix Metalloproteinases-2/-9 is Associated With Microvessel Density in Pancreatic Cancer

This study aimed to investigate the association of matrix-metalloproteinase (MMP)-2 and MMP-9 with microvessel density (MVD) in pancreatic cancer. The tumor tissues and para-tumor tissues of 30 patients with pancreatic cancer were pathologically examined. The normal pancreatic tissues of another 17 patients served as controls. The expression of MMP-2 and MMP-9 was examined using immunohistochemistry and scored. The association of MMP-2 and MMP-9 with the MVD values and pathological features were analyzed. The positive expression rates of MMP-2 and MMP-9 in the tumor tissues were significantly higher than those in the para-tumor tissues (P < 0.01). In normal pancreatic tissues, both MMP-2 and MMP-9 expressions were negative. The MVD values increased significantly along with higher tumor node metastasis stages (P = 0.04). The MVD values were positively correlated with MMP-2 scores (r = 0.563, P < 0.05) and MMP-9 scores (r = 0.451, P < 0.05). The expression of MMP-2 and MMP-9 is associated with angiogenesis in pancreatic cancer. MMPs might be used as prognostic factors and therapy targets for patients with pancreatic cancer.

Systemic delivery of microencapsulated 3-bromopyruvate for the therapy of pancreatic cancer

PURPOSE

This study characterized the therapeutic efficacy of a systemically administered formulation of 3-bromopyruvate (3-BrPA), microencapsulated in a complex with β-cyclodextrin (β-CD), using an orthotopic xenograft mouse model of pancreatic ductal adenocarcinoma (PDAC).

EXPERIMENTAL DESIGN

The presence of the β-CD-3-BrPA complex was confirmed using nuclear magnetic resonance spectroscopy. Monolayer as well as three-dimensional organotypic cell culture was used to determine the half-maximal inhibitory concentrations (IC50) of β-CD-3-BrPA, free 3-BrPA, β-CD (control), and gemcitabine in MiaPaCa-2 and Suit-2 cell lines, both in normoxia and hypoxia. Phase-contrast microscopy, bioluminescence imaging (BLI), as well as zymography and Matrigel assays were used to characterize the effects of the drug in vitro. An orthotopic lucMiaPaCa-2 xenograft tumor model was used to investigate the in vivo efficacy.

RESULTS

β-CD-3-BrPA and free 3-BrPA demonstrated an almost identical IC50 profile in both PDAC cell lines with higher sensitivity in hypoxia. Using the Matrigel invasion assay as well as zymography, 3-BrPA showed anti-invasive effects in sublethal drug concentrations. In vivo, animals treated with β-CD-3-BrPA demonstrated minimal or no tumor progression as evident by the BLI signal as opposed to animals treated with gemcitabine or the β-CD (60-fold and 140-fold signal increase, respectively). In contrast to animals treated with free 3-BrPA, no lethal toxicity was observed for β-CD-3-BrPA.

CONCLUSION

The microencapsulation of 3-BrPA represents a promising step towards achieving the goal of systemically deliverable antiglycolytic tumor therapy. The strong anticancer effects of β-CD-3-BrPA combined with its favorable toxicity profile suggest that clinical trials, particularly in patients with PDAC, should be considered.

Urinary TIMP-1 and MMP-2 levels detect the presence of pancreatic malignancies

Background:

A majority of patients with pancreatic malignancies, including both pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine tumours (pNETs), present with advanced disease due to a lack of specific symptoms and current diagnostic limitations, making this disease extremely difficult to detect. Our goal was to determine whether urinary matrix metalloproteases (uMMPs) and/or their endogenous inhibitors, urinary tissue inhibitor of metalloproteases (uTIMPs), could be detected in the urine of patients with pancreatic malignancies and whether they may serve as independent predictors of disease status.

Methods:

Retrospective analyses of urine samples (n=139) from PDAC and pNET patients as well as age- and sex-matched controls were conducted. Urinary MMP-2 and uTIMP-1 levels were determined using ELISA and zymography. Biomarker expression in tumour and normal pancreatic tissues was analysed via immunohistochemistry (IHC).

Results:

Multivariable logistic regression analyses indicated that, when controlling for age and sex, uMMP-2 (P<0.0001) and uTIMP-1 (P<0.0001) but not uMMP-9, were significant independent predictors for distinguishing between PDAC patients and healthy controls. Our data also indicated that uMMP-2 was an independent predictor of the presence of pNET. In addition, uTIMP-1 levels could differentiate the two cancer groups, PDAC and pNET, respectively. Immunohistochemistry analysis confirmed that MMP-2 and TIMP-1 protein expression is significantly upregulated in PDAC tissue compared with the normal pancreas.

Conclusions:

Taken together, our results suggest that the detection of uMMP-2 and uTIMP-1 may have diagnostic value in the detection of pancreatic malignancies and that uTIMP-1 may be useful in distinguishing between pancreatic adenocarcinoma and neuroendocrine tumours.

Highly Protective Association of MMP-2-1306C/T Promoter Polymorphism With Asthma in a North Indian Population: A Pilot Study

Purpose

Asthma is the most prevalent disease in India according to the national survey conducted by NFHS 2 in 1998-1999. Matrix metalloproteinase-2 (MMP-2), a collagenase encoded by the MMP-2 gene, degrades the type IV collagen and is responsible for inflammatory responses. This is a pilot study evaluating the role of MMP-2 -1306C/T promoter single nucleotide polymorphism (SNP) in asthma pathogenesis.

Methods

A case-control study was performed with a total of 824 adult subjects, including 410 adult asthmatics and 414 healthy controls from regions of North India. The MMP-2 -1306C/T polymorphism was genotyped by the Tetra-Primer Amplification Refractory Mutation System Polymerase Chain Reaction (Tetra-Primer ARMS PCR).

Results

Statistical analysis of the results for the MMP-2 -1306C/T polymorphism revealed an extremely protective role of the mutant T allele in asthma pathogenesis with OR=0.45, 95% CI (0.35-0.58) and P=0.000. The heterozygous CT genotype also conferred protection from asthma with OR=0.37, 95% CI (0.27-0.51) and P=0.000. The homozygous TT genotype was also significantly associated with asthma with OR=0.35, 95% CI (0.16-0.72) and P=0.002. Moreover, the polymorphism was significantly associated with all the phenotypic traits of the disease.

Conclusion

The MMP-2 -1306C/T promoter polymorphism confers significant protection from asthma in the studied North Indian population

Chlorotoxin-Fc fusion inhibits release of MMP-2 from pancreatic cancer cells

Chlorotoxin (CTX) is a 36-amino acid peptide derived from Leiurus quinquestriatus (scorpion) venom, which inhibits low-conductance chloride channels in colonic epithelial cells. It has been reported that CTX also binds to matrix metalloproteinase-2 (MMP-2), membrane type-1 MMP, and tissue inhibitor of metalloproteinase-2, as well as CLC-3 chloride ion channels and other proteins. Pancreatic cancer cells require the activation of MMP-2 during invasion and migration. In this study, the fusion protein was generated by joining the CTX peptide to the amino terminus of the human IgG-Fc domain without a hinge domain, the monomeric form of chlorotoxin (M-CTX-Fc). The resulting fusion protein was then used to target pancreatic cancer cells (PANC-1) in vitro. M-CTX-Fc decreased MMP-2 release into the media of PANC-1 cells in a dose-dependent manner. M-CTX-Fc internalization into PANC-1 cells was observed. When the cells were treated with chlorpromazine (CPZ), the internalization of the fusion protein was reduced, implicating a clathrin-dependent internalization mechanism of M-CTX-Fc in PANC-1 cells. Furthermore, M-CTX-Fc clearly exhibited the inhibition of the migration depending on the concentration, but human IgG, as negative control of Fc, was not affected. The M-CTX-Fc may be an effective instrument for targeting pancreatic cancer.

Role of Peroxisome Proliferator-Activated Receptor β/δ and B-Cell Lymphoma-6 in Regulation of Genes Involved in Metastasis and Migration in Pancreatic Cancer Cells

PPARβ/δ is a ligand-activated transcription factor that regulates various cellular functions via induction of target genes directly or in concert with its associated transcriptional repressor, BCL-6. Matrix remodeling proteinases are frequently over-expressed in pancreatic cancer and are involved with metastasis. The present study tested the hypothesis that PPARβ/δ is expressed in human pancreatic cancer cells and that its activation could regulate MMP-9, decreasing cancer cells ability to transverse the basement membrane. In human pancreatic cancer tissue there was significantly higher expression of MMP-9 and PPARβ/δ, and lower levels of BCL-6 mRNA. PPARβ/δ activation reduced the TNF α -induced expression of various genes implicated in metastasis and reduced the invasion through a basement membrane in cell culture models. Through the use of short hairpin RNA inhibitors of PPARβ/δ, BCL-6, and MMP-9, it was evident that PPARβ/δ was responsible for the ligand-dependent effects whereas BCL-6 dissociation upon GW501516 treatment was ultimately responsible for decreasing MMP-9 expression and hence invasion activity. These results suggest that PPARβ/δ plays a role in regulating pancreatic cancer cell invasion through regulation of genes via ligand-dependent release of BCL-6 and that activation of the receptor may provide an alternative therapeutic method for controlling migration and metastasis.

Targeting the cancer-stroma interaction: a potential approach for pancreatic cancer treatment

Recent studies have demonstrated that the interaction between the cancer and the stroma, play a key role in the development of pancreatic cancer. The desmoplasia, which consists of fibroblasts, pancreatic stellate cells, lymphatic and vascular endothelial cells, immune cells, pathologic increased nerves, and the extracellular matrix (ECM), creates a complex tumor microenvironment that promotes pancreatic cancer development, invasion, metastasis, and resistance to chemotherapy. Thus, the potential approach for targeting the components of this desmoplastic reaction or the pancreatic tumor microenvironment might represent a novel therapeutic approach to advanced pancreatic carcinoma. Novel therapies that target on the pancreatic tumor microenvironment should become one of the more effective treatments for pancreatic cancer.

Role of glial cell line-derived neurotrophic factor in perineural invasion of pancreatic cancer

Perineural invasion (PNI) is the initial infiltration of tumor cells into the retroperitoneal nerve plexus and along the nerves. It precludes curative resection, is thought to be the major cause of local recurrence following resection, and is a special metastatic route in pancreatic cancer. Glial cell line-derived neurotrophic factor (GDNF) was recently recognized as a key player in the PNI process. This review covers the most recently published studies on the role of GDNF in pancreatic cancer. We introduce the players in PNI, summarize the distribution of GDNF and its receptors in pancreatic cancer, and discuss the effects and underlying mechanism of GDNF in the PNI process. Finally, we also review some potential inhibitors for GDNF-targeted therapy.

Modified dendrimer cross-linked collagen-based matrices

Dendrimer cross-linking has been achieved with pepsin digested over 80% type-I bovine collagen to create strong hydrogels with good cell compatibility. Herein we investigate the use of commercially available collagen-based products with the dendrimer cross-linking technology. Specifically PureCol(®) (PC), a 97% bovine type-I collagen, human collagen (HC) and human extracellular matrix (hECM) were concentrated, and then cross-linked with polypropyleneimine octaamine generation two dendrimers using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) chemistry. PC gels with 30 and 20 mg/ml bovine collagen were fabricated, and despite similar concentrations to >80% type-I bovine collagen dendrimer cross-linked gels (CG), PC gels demonstrated increased swelling and decreased stability, as determined with collagenase digestion. The highly purified bovine (PC) and human sourced-collagen (HC) gels were similar in performance, but not as stable as the CG gels, which may correlate to the manufacturer's collagen purification and storage. Finally, the addition of hECM components to PC to create PC-hECM gels, resulted in a looser gel network, compared to heparinized dendrimer cross- linked bovine >80% type-I collagen gels (CHG). However, all collagen-based gels supported 3T3 fibroblast cell growth over 4 days, indicating these gels may be suitable for tissue-engineering applications.

Significance of combination therapy of zoledronic acid and gemcitabine on pancreatic cancer

In the present study, we examined the cytotoxic effects of combination therapy with zoledronic acid (ZOL) and gemcitabine (GEM) on pancreatic cancer cells in vitro and in vivo. Four human pancreatic cancer cell lines were treated with ZOL, GEM or a combination of both, and the effects of the respective drug regimens on cell proliferation, invasion and matrix metalloproteinase (MMP) expression were examined. A pancreatic cancer cell line was also intrasplenically or orthotopically implanted into athymic mice and the effects of these drugs on tumor metastasis and growth in vivo were evaluated by histological and immunohistochemical analyses. Combination treatment with low doses of ZOL and GEM efficiently inhibited the proliferation (P < 0.001) and invasion (P < 0.001) of pancreatic cancer cells in vitro. Western blotting assay revealed that MMP-2 and MMP-9 expression levels were decreased after ZOL treatment. In vivo, combined treatment significantly inhibited tumor growth (P < 0.05) and the development of liver metastasis (P < 0.05). These data revealed that ZOL and GEM, when used in combination, have significant antitumor, anti-metastatic and anti-angiogenic effects on pancreatic cancer cells. The present study is the first to report the significance of the combination treatment of ZOL and GEM in pancreatic cancer using an in vivo model. These data are promising for the future application of this drug regimen in patients with pancreatic cancer.

Angiogenesis In Vitro Utilizing Murine Vascular Explants in Miniaturized 3-Dimensional Collagen Gels

Models of angiogenesis in vitro are used to study blood vessel morphogenesis and the effects of compounds that influence vascular growth. Herein, we describe techniques to induce angiogenesis-like sprouting from explants of mouse aortae and microvessels cultured in 3-dimensional gels of native type I collagen. The gels are supported by rings of nylon mesh that are sized to fit in 96-well culture plates. This mechanically-supported, miniaturized, 3-dimensional culture system requires only small quantities of cells and reagents and facilitates handling, staining, and imaging by conventional and confocal microscopy.

Clinical significance of the measurements of serum matrix metalloproteinase-9 and its inhibitor (tissue inhibitor of metalloproteinase-1) in patients with pancreatic cancer: metalloproteinase-9 as an independent prognostic factor

OBJECTIVE

Pancreatic cancer (PC) is a malignant tumor with high mortality. Aggressive growth and metastases of PC are the result of basement membrane degradation that may be attributed to the action of matrix metalloproteinase-9 (MMP-9). The aim of the study was to determine the diagnostic and prognostic significance of the measurements of serum MMP-9 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in patients with PC.

METHODS

The study involved 78 patients with PC, 45 with chronic pancreatitis, and 70 healthy subjects. We assayed the serum concentrations of MMP-9, TIMP-1, and classic tumor markers (carbohydrate antigen 19-9 and carcinoembryonic antigen) and defined the prognostic value and the diagnostic criteria for all the proteins tested.

RESULTS

In the patients with PC, the serum levels of MMP-9, TIMP-1, and the tumor markers were higher as compared with those in the patients with chronic pancreatitis and the healthy subjects. The diagnostic sensitivity and the area under the receiver operating characteristic curve for TIMP-1 were higher than for MMP-9 and the tumor markers. The elevated preoperative concentration of MMP-9 was a significant independent prognostic factor for the patients' survival.

CONCLUSIONS

These findings indicate a potential clinical significance of serum TIMP-1 and MMP-9 measurements in the diagnosis and prognosis of patients with PC, respectively.

Characterization of tumor-derived pancreatic stellate cells

BACKGROUND

Pancreatic stellate cells (PSCs) are key mediators of the desmoplastic reaction that characterizes pancreatic adenocarcinoma. We sought to isolate and characterize tumor-derived pancreatic stellate (TDPS) cells to further understand how these stromal cells influence pancreatic cancer behavior.

METHODS

We established a stable line of non-immortalized PSCs from a patient with pancreatic adenocarcinoma using a modified prolonged outgrowth method. Cell staining for cytokeratin, vimentin, and alpha smooth muscle actin (alphaSMA) was performed. Total RNA was harvested from TDPS and panc-1 cells and gene expression determined by microarray analysis.

RESULTS

TDPS cells contain lipid droplets in the cytoplasm, and later stain positive for both vimentin and alphaSMA, indicative of activated myofibroblasts. Microarray analysis revealed a distinct gene expression profile compared with pancreatic cancer cells, including expression of proteases that facilitate cancer cell invasion and growth factors known to activate pancreatic cancer cells. Additionally, TDPS cells expressed many of the key components of the pancreatic tumor stroma, including collagen, fibronectin, and S100A4, confirming their importance in the tumor microenvironment.

CONCLUSIONS

Characterization of tumor-derived PSCs will facilitate further studies to determine how the tumor microenvironment promotes the aggressive behavior of pancreatic cancer.

Ape1/Ref-1 induces glial cell-derived neurotropic factor (GDNF) responsiveness by upregulating GDNF receptor alpha1 expression

Apurinic/apyrimidinic endonuclease 1 (Ape1/Ref-1) dysregulation has been identified in several human tumors and in patients with a variety of neurodegenerative diseases. However, the function of Ape1/Ref-1 is unclear. We show here that Ape1/Ref-1 increases the expression of glial cell-derived neurotropic factor (GDNF) receptor alpha1 (GFRalpha1), a key receptor for GDNF. Expression of Ape1/Ref-1 led to an increase in the GDNF responsiveness in human fibroblast. Ape1/Ref-1 induced GFRalpha1 transcription through enhanced binding of NF-kappaB complexes to the GFRalpha1 promoter. GFRalpha1 levels correlate proportionally with Ape1/Ref-1 in cancer cells. The knockdown of endogenous Ape1/Ref-1 in pancreatic cancer cells markedly suppressed GFRalpha1 expression and invasion in response to GNDF, while overexpression of GFRalpha1 restored invasion. In neuronal cells, the Ape1/Ref-1-mediated increase in GDNF responsiveness not only stimulated neurite outgrowth but also protected the cells from beta-amyloid peptide and oxidative stress. Our results show that Ape1/Ref-1 is a novel physiological regulator of GDNF responsiveness, and they also suggest that Ape1/Ref-1-induced GFRalpha1 expression may play important roles in pancreatic cancer progression and neuronal cell survival.

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.

Predictive value of lymph node and tumor matrix metalloproteinase expression in the analysis of metastatic periampullary tumors

BACKGROUND AND OBJECTIVES

Matrix metalloproteinases (MMP) are endogenous peptidases capable of degrading various components of the basement membrane. The ability of malignant epithelial cells to degrade extracellular matrix and basement membrane is an important step in the process of metastatic invasion. In this study, we prospectively compared the outcome of patients undergoing laparotomy for resection of periampullary malignancies with lymph node and tumor MMP expression to determine if there was a correlation between metalloproteinase expression and patient outcome.

METHODS

Sixteen patients undergoing operation were followed prospectively. Expression of MMP-2 and -9 and their inhibitors TIMP (tissue inhibitor of matrix metalloproteinase) -1 and -2 were measured in lymph node and tumor samples by semiquantitative PCR analysis.

RESULTS

All patients who died from their disease process had significantly greater MMP-2 expression in their lymph nodes relative to TIMP-2 expression. In contrast, patients with prolonged disease-free survival had decreased nodal MMP-2/TIMP-2 expression (P = 0.001). Patients with relatively higher MMP-2/TIMP-2 expression in their tumors also had a worse prognosis (P = 0.06).

CONCLUSION

The data demonstrate that the mRNA expression of MMPs and TIMPs in the draining lymph node of patients with periampullary adenocarcinomas may hold prognostic significance for patient survival. This prognostic information may be of use in patients when planning future adjuvant therapies.

Prostaglandin E2 enhances pancreatic cancer invasiveness through an Ets-1-dependent induction of matrix metalloproteinase-2

Accumulating evidence suggests an important role for cyclooxygenase-2 (COX-2) in the pathogenesis of a wide range of malignancies. Here we tested the hypothesis that the COX-2 product prostaglandin E(2) (PGE(2)) increases cellular invasive potential by inducing matrix metalloproteinase-2 (MMP-2) expression and activity through an extracellular signal-regulated kinase (ERK)/Ets-1-dependent mechanism in pancreatic cancer. PANC-1 and MIAPaCa-2 pancreatic cancer cells were treated with PGE(2) or rofecoxib, a selective COX-2 inhibitor. MMP-2 expression and activity were assayed using Western blot analysis and zymography, respectively. MMP-2 promoter activity was analyzed with a luciferase-based assay. Ets-1 activity was analyzed using gel shift assay. Ets-1 expression was specifically silenced using RNA interference. Cellular invasive and migratory potentials were determined using a Boyden chamber assay with or without Matrigel, respectively. Exogenous PGE(2) induced MMP-2 expression and activity and increased ERK1/2 phosphorylation, Ets-1 binding activity, and MMP-2 promoter activity. PGE(2) also increased cellular migratory and invasive potentials. The mitogen-activated protein kinase kinase inhibitor PD98059 and Ets-1 silencing each abolished PGE(2)-induced increases in MMP-2 expression. PD98059 and Ets-1 silencing each abrogated the effect of PGE(2) on cellular invasive potential but not on cellular migratory potential. Rofecoxib suppressed MMP-2 expression and activity, Ets-1 binding activity, MMP-2 promoter activity, and cellular migratory and invasive potentials. These results suggest that PGE(2) mediates pancreatic cancer cellular invasiveness through an ERK/Ets-1-dependent induction of MMP-2 expression and activity. They also suggest that COX-2 inhibition may represent a strategy to inhibit invasive potential in pancreatic cancer.

Nerve growth factor stimulates MMP-2 expression and activity and increases invasion by human pancreatic cancer cells

Pancreatic cancer frequently invades and migrates along neural tissue. Although the exact mechanisms are unknown, perineural invasion negatively impacts prognosis for pancreatic cancer patients. Matrix metalloproteinases (MMPs) are overexpressed in pancreatic cancer and are associated with poor prognosis. We hypothesized that nerve growth factor (NGF) released from neural tissue increases the invasive properties of pancreatic cancer cells. In the present study we investigated the effect of NGF on the expression and activity of MMP-2 in human pancreatic cancer cells. NGF dose dependently increased MMP-2 protein in the culture medium and stimulated MMP-2 gelatinolytic activity. This effect was mediated by specific binding of NGF to its receptor trk A, which was detected on all pancreatic cancer cells, with subsequent activation of the p44/42 MAPK signaling pathway. The NGF-induced increase in MMP-2 expression and activity lead to an enhanced invasion in vitro. These findings support the hypothesis that neurotrophic factors, e.g., NGF, are critically involved in mediating perineural invasion of pancreatic cancer.

RETRACTED: Glucose transporter-1 gene expression is associated with pancreatic cancer invasiveness and MMP-2 activity

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors-in-Chiefs, because an investigation by Harvard Medical School and the Brigham and Women’s Hospital has concluded that Figure 3 is invalid and no underlying research data are available to resolve the discrepancies or validate the reported results.

Inhibition and mechanism of action of a protease inhibitor in human pancreatic cancer cells

OBJECTIVES

Tumor-associated trypsinogen (TAT), urokinase-type plasminogen activator (u-PA), matrix metalloproteinase-2 (MMP-2), and MMP-9 each play a dominant role in the degradation of extracellular matrix (ECM) during the invasion process of pancreatic cancer. Transforming growth factor beta1 (TGF-beta1) is a multifunctional poly-peptide that regulates cell growth and differentiation, ECM deposition, cellular adhesion properties, angiogenesis, and also immune functions. We previously reported that TGF-beta1 up-regulated vascular endothelial growth factor (VEGF) production and protease production of MMP-2 and of u-PA in the highly metastatic pancreatic cancer cell lines SW1990 and CAPAN-2. In this study, we examined the inhibitor effects of a protease inhibitor, gabexate mesilate (GM), on cell invasion, cell proliferation, growth factor production, and ECM degradation. We also examined the effect of GM on the production of growth factor and ECM degradation by these cell proteases and enzymatic activities.

RESULTS

GM down-regulated the invasiveness and liver metastasis potential of SW1990 and CAPAN-2 cells, but it did not affect the proliferation of these cells. GM inhibited not only the enzymatic activities of TAT and u-PA but also the production of MMP-2, and u-PA, all of which have been known to be secondarily down-regulated by TGF-beta1.

CONCLUSIONS

These findings suggested that GM has very good potential for use in the treatment against invasion and metastasis of pancreatic cancer.

The Integrin Cytoplasmic-tail Motif EKQKVDLSTDC Is Sufficient to Promote Tumor Cell Invasion Mediated by Matrix Metalloproteinase (MMP)-2 or MMP-9

Integrins promote cellular invasion through a combination of activities, including adhesion to an extracellular matrix ligand, which result in the generation of intracellular signals that lead to changes in cell behavior. Until now, there have been no data that identify a particular region of the cytoplasmic tail of integrin subunits as being responsible specifically for promoting the invasive activity of tumor cells. In this report, we show that amino acids with the sequence EKQKVDLSTDC, which are the C-terminal residues of the integrin beta6 subunit, promote alphavbeta6-dependent invasion in a matrix metalloproteinase (MMP)-9-dependent fashion. This same peptide sequence, when expressed at the cytoplasmic end of the beta3 integrin subunit, was able to enhance alphavbeta3-mediated invasive and enzymatic activity of tumor cells in an MMP-2-dependent fashion. Our results show that these 11 amino acids, when expressed at the C terminus of the beta subunit, are responsible for regulating the activity of invasion-promoting degradative enzymes, whereas the specific MMP involved in this cellular behavior is dependent on the context of the remainder of the beta integrin subunit.

Activity of the matrix metalloproteinase-9 promoter in human normal and tumor cells

Matrix metalloproteinases (MMPs) belong to a family of proteins essential for those processes involving extracellular matrix degradation, such as embryonic development, morphogenesis, and tissue resorption and remodeling. Some members of this family play a crucial role also in tumor invasion. Most notably, MMP-9 is expressed in invasive tumors, and represents a key protein in brain tumor progression, whereas it is not expressed in adult normal tissues. The expression of the MMP-9, like other members of the family, is transcriptionally regulated. We, therefore, postulated that the MMP-9 promoter could be useful in driving selective expression of exogenous genes in tumor cells. This represents a key feature for gene therapy applications, since currently employed viral promoters induce severe organ toxicity, limiting the clinical benefits. In this study, we investigated the activity of the MMP-9 promoter in driving exogenous gene expression in human cell lines. High levels of reporter gene expression were detected in tumor derived cell lines, whereas the MMP-9 promoter activity in non-tumor cells was negligible. Furthermore, we show that tumor necrosis factor alpha (TNFalpha) is able to enhance considerably the MMP-9 promoter activity only in tumor cells. Since recent studies have indicated that MMP-9 enzymatic activity is detectable in the blood, it would be possible to screen potential responsive patients for a tumor gene therapy approach based on the MMP-9 promoter. Taken together these data suggest that MMP-9 promoter has the characteristics for transcritpionally targeted and inducible gene therapy applications.

Glial cell-derived neurotrophic factor upregulates the expression and activation of matrix metalloproteinase-9 in human pancreatic cancer

BACKGROUND

We have previously reported that the glial cell-derived neurotrophic factor (GDNF) promotes pancreatic cancer cell invasion in vitro. The purpose of this study was to determine whether GDNF regulates the expression and activation of matrix metalloproteinase-9 (MMP-9) in human pancreatic cancer cells.

METHODS

We used human pancreatic cancer cell line MIA PaCa-2. The effect of GDNF on mRNA and protein expression was measured by Northern blot, Western blot and enzyme-linked immunosorbent assay. MMP proteolytic activity was detected by gelatin zymography. To determine which intracellular pathways were involved, we used the following inhibitors: tyrosine kinase inhibitor Genistein, MEK-1 inhibitor PD98059 and PI3-K inhibitor Wortmannin.

RESULTS

GDNF increased MMP-9 mRNA and protein expression in MIA PaCa-2 cells in a dose-dependent manner. Treatment with GDNF enhanced gelatinolytic activity of the pro and active form of MMP-9. Inhibitor experiments showed that the expression and activity of pro MMP-9 was totally inhibited by Genistein and partially by Wortmannin, whereas PD98059 had no effect. All three compounds inhibited the activity of the active form of MMP-9.

CONCLUSIONS

GDNF upregulates the expression and enzymatic activity of MMP-9 through different signaling pathways in MIA PaCa-2. These findings suggest that GDNF modulates MMP-9 expression and activation, and this may promote pancreatic cancer invasion.

Inhibition of tyrosine kinase Src suppresses pancreatic cancer invasiveness

BACKGROUND

Src is a 60-kDa tyrosine kinase that plays a critical role in signal transduction associated with cell-extracellular matrix interactions. We tested the hypothesis that Src inhibition might suppress pancreatic cancer cellular invasiveness.

METHODS

We tested the effects of pyrazolopyrimidine (a Src kinase-specific inhibitor) on 3 human pancreatic cancer cell lines: BXPC-3, MIAPaCa-2, and PANC-1. Src expression was assayed with Western blotting. Pyrazolopyrimidine-mediated inhibition of Src phosphorylation was confirmed by immunoprecipitation. Matrix metalloproteinase (MMP) activities and cellular invasive potential were assessed by use of zymography and Boyden chamber assays, respectively. Cell growth was assessed with the MTT assay.

RESULTS

Src was expressed in all 3 pancreatic cancer cell lines tested. Pyrazolopyrimidine completely suppressed Src phosphorylation, inhibited MMP2 (72kDa) and MMP9 (92kDa) activities by 40% to 34% (P <.05), and suppressed cellular invasiveness by more than 90% (P <.05) in all 3 cell lines. Pyrazolopyrimidine had variable effects on cell growth: 50% reduction (P <.05) in BXPC-3, 7% reduction (P >.05) in MIAPaCa-2, and 22% reduction (P <.05) in PANC-1.

CONCLUSIONS

Inhibition of Src signaling results in a marked reduction of pancreatic cancer cellular invasiveness. Src may represent a novel therapeutic target for this deadly cancer.

Selective activation of PPARgamma inhibits pancreatic cancer invasion and decreases expression of tissue plasminogen activator

BACKGROUND

PPARgamma is a ligand-activated transcription factor with antitumor effects; its ability to inhibit pancreatic cancer invasion is unknown. The purpose of this study was to define the inhibitory effect of PPARgamma ligands on pancreatic cancer invasion and the expression of invasion-related genes.

METHODS

Western blotting was used to establish expression of PPARgamma in AsPC-1 and SUIT-2 cells. AsPC-1 cells were treated with nontoxic doses of PPARgamma ligands (15d-PGJ(2), troglitazone, or rosiglitazone) and Matrigel Invasion chambers were used to assess invasion in vitro. A microarray for genes that contribute to invasion was used to investigate the antiinvasive targets of PPARgamma. Gene array results were confirmed by use of ribonuclease protection assay or Northern blotting.

RESULTS

Rosiglitazone and 15d-PGJ(2) decreased AsPC-1 cell invasion; GW9662, which inhibits PPARgamma, reversed this effect. The expression of tissue plasminogen activator (tPA) was decreased by rosiglitazone treatment, which was confirmed by Northern blotting. Secreted levels of tPA in AsPC-1 conditioned media were also decreased.

CONCLUSIONS

We demonstrate, for the first time, that secretion of the invasive factor tPA was decreased by rosiglitazone treatment in AsPC-1 cells. PPARgamma ligands inhibit pancreatic cancer cell invasion, suggesting that these agents may represent novel strategies to treat pancreatic cancer.

Inhibition of matrix metalloproteinase-14 in osteosarcoma cells by clodronate

BACKGROUND

Bisphosphonates reduce the bone metastasis formation and angiogenesis but the exact molecular mechanisms involved are unclear. Progelatinase A (proMMP-2; 78 KDa) is activated up during the tumor spread and metastasis by a cell surface-associated matrix metalloproteinase (membrane-type matrix metalloproteinase [MT1-MMP] or MMP-14).

MATERIAL AND METHODS

We evaluated the effects of a bisphosphonate (clodronate) on MT1-MMP mRNA expression and protein production, catalytic activity and proteolytic activation of proMMP-2 by cultured human MG-63 osteosarcoma cells.

RESULTS

Clodronate, at therapeutically attainable noncytotoxic concentrations, dose-dependently inhibited phorbol myristic acetate (PMA)-induced proteolytic activation of proMMP-2 by human MG-63 osteosarcoma cells. Clodronate also downregulated the PMA-induced expression of MT1-MMP mRNA and protein production in human MG-63 osteosarcoma cells, as evidenced by Northern analysis and fluorescent immunohistochemistry. Furthermore, clodronate inhibited directly and dose-dependently MT1-MMP activity, and the MT1-MMP inhibition by clodronate was reduced in the presence of an increased (5 mM) Ca(2+) concentrations when compared to physiological (1 mM) Ca(2+) concentrations.

CONCLUSION

We conclude that (1) the extracellular/cell-associated mechanism of bisphosphonate involves inhibition of MT1-MMP catalytic activity eventually by chelation, and that (2) intracellular mechanism involves downregulation of induced MT1-MMP mRNA and protein expression. The inhibition and downregulation of MT1-MMP by clodronate can be related to their ability to reduce MG-63 osteosarcoma cell invasion and spread. These findings may, at least in part, explain at molecular level the antitumor and antibone resorption activities of clodronate observed in clinical studies.

Matrix metalloproteinase expression in breast cancer

BACKGROUND

Matrix metalloproteinases (MMPs) have been implicated as possible mediators of invasion and metastasis in some cancers. Our objective was to investigate which MMPs were constitutively expressed in breast tumor cells versus those that could be up-regulated by a number of agents known to affect MMP expression in other cell systems.

METHODS

We evaluated expression of MMPs 1-16 in breast tumor cell lines MDA-MB-231, T47D, and MCF-7 using semiquantitative RT-PCR and gelatin zymography. Exposure to 12-O-tetradecanoylphorbal-3-acetate (TPA), concanavalin-A (Con-A), the fibronectin-mimetic peptide GRGDSP (RGD), extracellular matrix (ECM) components, and anti-integrin antibodies was used to test for possible MMP up-regulation. Mitogen-activated protein kinase inhibitors (MAPK-I) were used to evaluate signal transduction pathways and regulation of MMP expression.

RESULTS

MMPs 1, 2, 7-11, 13, 14, and 16 were constitutively expressed in some tumor cell lines but not in normal breast epithelial cells. Administration of TPA, Con-A, and RGD increased the expression of MMPs 1, 2, 9, and 10. No MMP up-regulation was seen in MDA-MB-231 or MCF-7 after exposure to ECM components or after exposure to anti-integrin antibodies. MAPK-I had no effect on constitutive MMP expression but reduced or abolished the TPA up-regulation of MMP-9 in MDA-MB-231 and MCF-7.

CONCLUSIONS

Breast tumor cell lines constitutively express a number of MMPs. Because MMP expression can be up-regulated by Con-A, the fibronectin-mimetic peptide RGD, and TPA while being susceptible to inhibition by MAPK antagonists, MAPK signaling appears to play a role in this expression.

Up-regulation of matrix metalloproteinase 9 by thrombospondin 1 in gastric cancer

BACKGROUND

Matrix metalloproteinase 9 (MMP-9) plays a key role in tumor cell invasion. It was recently reported that plasma levels of MMP-9 in patients with gastric cancer correlate with the tumors' metastatic potential. We previously demonstrated that thrombospondin 1 (TSP-1) up-regulates MMP-9 expression by endothelial cells and promotes tumor cell invasion. We hypothesized that TSP-1 plays a role in the up-regulation of MMP-9 in gastric cancer.

METHODS

MMP-9, TSP-1, and CSVTCG-specific TSP-1 receptor expression were measured by immunohistochemical staining in 31 consecutive gastric adenocarcinomas from patients who did not undergo neoadjuvant chemotherapy or radiation therapy. Additionally, we measured TSP-1, CSVTCG-specific TSP-1 receptor, and MMP-9 expression by Western blotting, zymography, and immunohistochemical staining in AGS gastric adenocarcinoma cells. We also investigated the effect of TSP-1 on MMP-9 expression by AGS cells.

RESULTS

TSP-1 localized to the tumor-associated extracellular matrix. CSVTCG-specific TSP-1 receptor and MMP-9 colocalized to tumor cells, fibroblasts, and tumor-associated microvessels. Intense staining for TSP-1, CSVTCG-specific TSP-1 receptor, and MMP-9 correlated with markers of aggressive tumor behavior. AGS gastric adenocarcinoma cells expressed high levels of CSVTCG-specific TSP-1 receptor but not TSP-1. TSP-1 up-regulated MMP-9 expression by AGS cells.

CONCLUSIONS

We conclude that TSP-1 plays a role in the up-regulation of MMP-9 expression in gastric cancer. Our data also suggest a correlation between expression of TSP-1, CSVTCG-specific TSP-1 receptor, and MMP-9 and the acquisition of an aggressive tumor phenotype.

Taxotere resistance in SUIT Taxotere resistance in pancreatic carcinoma cell line SUIT 2 and its sublines

AIM: To investigate the specific mechanisms of intrinsic and acquired resistance to taxotere (TXT) in pancreatic adenocarcinoma (PAC).

METHODS: MTT assay was used to detect the sensitivity of PAC cell line SUIT-2 and its sublines (S-007, S-013, S-020, S-028 and TXT selected SUIT-2 cell line, S2/TXT) to TXT. Mdr1 (P-gp), multidrug resistance associated protein (MRP), lung resistance protein (LRP) and β-tubulin isotype gene expressions were detected by RT-PCR. The functionality of P-gp and MRP was tested using their specific blocker verapamil (Ver) and indomethacin (IMC), respectively. The transporter activity of P-gp was also confirmed by Rhodamine 123 accumulation assay.

RESULTS: S-020 and S2/TXT were found to be significantly resistant to TXT (19 and 9.5-fold to their parental cell line SUIT-2, respectively). RT-PCR demonstrated strong expression of Mdr1 in these two cell lines, but weaker expression or no expression in other cells lines. MRP and LRP expressions were found in most of these cell lines. The TXT-resistance in S2-020 and S2/TXT could be reversed almost completely by Ver, but not by IMC. Flow cytometry showed that Ver increased the accumulation of Rhodamine-123 in these two cell lines. Compared with S-020 and SUIT-2, the levels of β-tubulin isotype II, III expressio ns in S-2/TXT were increased remarkably.

CONCLUSION: The both intrinsic and acquired TXT-related drug resistance in these PAC cell lines is mainly mediated by P-gp, but had no relationship to MRP and LRP express ions. The increases of β-tubulin isotype II, III might be collateral changes that occur when the SUIT-2 cells are treated with TXT.