Proteolysis in human breast cancer

Development of a Risk Score Model for Osteosarcoma Based on DNA Methylation-Driven Differentially Expressed Genes

Osteosarcoma (OS) is the commonest malignant bone tumor in adolescent patients, and patients face amputation, tumor metastasis, chemotherapy resistance, and even death. We investigated the potential connection between abnormal methylation differentially expressed genes and the survival rate of osteosarcoma patients. GSE36002 and GSE12865 datasets of GEO database were utilized for abnormal methylation differentially expressed genes, followed by function and pathway enrichment analyses, the protein-protein interaction network in the STRING database, and cluster analysis in the MCODE app of Cytoscape. The RNA-seq and clinical data from the TARGET-OS project of TCGA were used for univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses to predict the risk genes of osteosarcoma. 1191 hypermethylation-downregulated genes might function through plasma membrane, negative regulation of transcription from the RNA polymerase II promoter, and pathways, including transcriptional misregulation in cancer. 127 hypomethylation-upregulated genes were enriched in proteolysis, negative regulation of the canonical Wnt signaling pathway, and metabolic signaling pathways. The univariate Cox analysis revealed 638 genes ( $P<0.01$ ), including 50 hypermethylation-downregulated genes and 4 hypomethylation-upregulated genes, subsequently based on LASSO Cox regression analysis for 54 aberrant methylation-driven genes, and three genes (COL13A1, MXI1, and TBRG1) were selected to construct the risk score model. The three genes (COL13A1, MXI1, and TBRG1) regulated by DNA methylation were identified to relate with the outcomes of OS patients, which might provide a new insight to the pathological mechanism of osteosarcoma.

Anti-cancer effect of metformin on the metastasis and invasion of primary breast cancer cells through mediating NF-kB activity

Current evidence strongly suggests that aberrant activation of the nuclear factor kappa B (NF-kB) signaling cascade is connected to carcinogenesis. The matrix metalloproteinases (MMP) which are also the key agents for tumor metastasis may be potent candidates for tumor diagnosis in clinics. In this in vitro study, we hypothesized that metformin with an effective dose can inhibit tumor cell proliferation and metastasis by modulating the expressions of MMP-2 and -9 and interfering with NF-kB signaling in primary breast cancer cells (PBCCs). 300 000 cells per ml were obtained from biopsies of breast tumors from five human donors. The cell viability and proliferation were tested. Immunocytochemistry was performed for MMP-2, MMP-9, and NF-kB, and enzyme-linked immunosorbent assay for NF-kB activity, quantitative real-time PCR for RELA/p65, IkBα, MMP-2, and MMP-9. Three different doses of metformin (5, 10, and 25 mM) (Met) reduced the viability and proliferation of PBCCs in a dose-dependent manner, maximum inhibition was observed at 25 mM Met. The expression of RELA/p65 was not affected by 25 mM Met. Nuclear immunoreactivity and activity of NF-kB reduced while cytoplasmic NF-kB (p65) elevated by 25 mM Met compared to non-treatment (P <  0.05). The expression and immunoreactivity of MMP-9 but not MMP-2 were decreased by 25 mM Met treatment, compared with the non-treatment (P <  0.05). Metformin may have an essential antitumor role in the invasion and metastasis pathways of PBCCs by downregulating the MMP-9 expression blocking both the activity and nuclear translocation of NF-kB.

Inhibition of platelet-derived growth factor C and their receptors additionally increases doxorubicin effects in triple-negative breast cancer cells

Complex of platelet-derived growth factor (PDGF) isoforms and PDGF receptors have important functions in the regulation of growth and survival of various cell types. Herein, it was found that aberrant PDGFC expression is closely associated with survival rates in triple-negative breast cancer (TNBC) patients. In addition, PDGFC expression was identified to be significantly increased in TNBC cells unlike other subtypes such as PDGFA, PDGFB, and PDGFD. Apparently, the effects of specific PDGF receptor (PDGFR) inhibitors such as sunitinib and ponatinib on HCC1806 and Hs578T TNBC cells were investigated. Both inhibitors decreased cell viability in a dose-dependent manner. In addition, the inhibitors completely inhibited cell growth in both the cell lines and decreased the expression of matrix metalloproteinase-1 (MMP-1), one of the metastasis-related genes. Cell migration was also decreased by the inhibitors. Finally, the combined effects of the inhibitors with doxorubicin (DOX) were investigated. The results showed that the combination of two PDGFR inhibitors with DOX inhibited the growth of cells and enhanced the apoptotic cell death more uniformly than DOX. Consequently, it is demonstrated that PDGFR inhibitors, sunitinib and ponatinib hold the potential for effective treatment of TNBC.

Analysis of the serum peptidome associated with Toxoplasma gondii infection

Toxoplasma gondii is an obligate intracellular parasite that can cause severe disease in immunocompromised individuals and congenitally infected neonates. In order to determine whether serum peptide profile could reveal disease markers or allow determination of toxoplasmosis aggressiveness, mouse sera were collected from acutely infected, chronically infected and control subjects, and analyzed by a quantitative label-free pepdomics approach (LC-MS/MS). Six hundred and seven endogenous peptides were identified among all samples, with peptide profiling of difference that readily distinguished between acutely infected samples and other samples. Among these peptides detected in this study, 81 and 68 differentially expressed peptides (DEPs) were found in the acute and chronic infection stages, respectively. Through Gene Ontology analysis, most of the precursor proteins of these DEPs were associated with biological regulation and binding activity. These findings in this study will help in the search of peptide targets with a key role in disease diagnosis and create new opportunities for the development of better means for the prevention and control of toxoplasmosis. SIGNIFICANCE: Toxoplasma gondii is an unicellular parasite which infects humans and a wide range of warm-blooded animals. The serum peptidome contains a large set of low molecular weight endogenous peptides derived from secretion, protease activity and PTMs. In the present study we quantified the effects of T. gondii infection on the serum peptidome to identify novel disease regulated secretory factors. We developed an optimized label-free LC-MS/MS method to analyze endogenous peptides during toxoplasmosis progression. This resulted in quantification of 607 unique peptides at both acute and chronic infection stages. Collectively, our deep peptidomic analysis of serum revealed that peptide variations were affected by disease development, and peptidomics is an ideal method for quantifying changes in circulating factors on a global scale in response to pathophysiological perturbations such as T. gondii infection.

Detection of Breast Cancer by Surface-enhanced Laser Desorption/Ionization Time-of-flight Mass Spectrometry Tissue and Serum Protein Profiling

Aim

Novel diagnostic breast cancer markers have been extensively searched for in the proteome, using, among others, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). Thus far, the majority of SELDI-TOF MS studies have investigated samples originating from biorepositories, which hampers biomarker discovery as they likely suffer from variable adherence to collection protocols.

Material and methods

We investigated breast cancer (n=75) and control (n=26) serum and tissue samples, collected prospectively by rigorous adherence to a strictly defined protocol. Sera were collected preoperatively and postoperatively, and serum and tissue samples were analyzed by SELDI-TOF MS using the IMAC30 Ni and Q10 pH 8 array.

Results

Three serum peaks were significantly associated with breast cancer, while in tissue, 27 discriminative peaks were detected. Several peak clusters gradually increased or decreased in intensity from healthy to benign to cancer, or with increasing cancer stage. The constructed classification trees had a tenfold cross-validated performance of 67% to 87%. Two tissue peaks were identified as N-terminal albumin fragments. These are likely to have been generated by (breast) cancer-specific proteolytic activity in the tumor microenvironment.

Conclusions

These albumin fragments can potentially provide insights into the pathophysiological mechanisms associated with, or underlying, breast cancer, and aid in improving breast cancer diagnosis.

Development of a fully automated chemiluminescence immunoassay for urine monomeric laminin-γ2 as a promising diagnostic tool of non-muscle invasive bladder cancer

BACKGROUND

Monomeric laminin-γ2 in urine is a potential biomarker for bladder cancer. However, the current detection system uses an antibody that cannot discriminate between monomeric laminin-γ2 and the heterotrimeric γ2 chain of laminin-332, which may cause false-positive reactions. The present study aimed to develop a fully automated chemiluminescence immunoassay system using a specific monoclonal antibody against monomeric laminin-γ2.

METHODS

In total, 237 urine specimens (84 from patients with bladder cancer, 48 from patients with benign urological disease, and 105 from healthy donors) were collected, and monomeric laminin-γ2 values in the urine were measured using a fully automated chemiluminescence immunoassay.

RESULTS

The results revealed that laminin-γ2 values in patients with benign urological disease were comparable to those of healthy donors and that the chemiluminescence immunoassay's lower limit of detection was 10 pg/mL (approximately 20-fold better than the sandwich enzyme-linked immunosorbent assay's limit of 200 pg/mL). Moreover, the chemiluminescence immunoassay demonstrated that patients with bladder cancer, including non-muscle invasive bladder cancer (≤pT1), had higher laminin-γ2 values than patients with benign urological disease or healthy donors.

CONCLUSIONS

These results suggest that urine monomeric laminin-γ2 may be a promising biomarker to diagnose cases of non-muscle invasive bladder cancer using a fully automated chemiluminescence immunoassay system.

Tricetin inhibits human osteosarcoma cells metastasis by transcriptionally repressing MMP-9 via p38 and Akt pathways

Tricetin, a dietary flavonoid, has cytostatic properties and anti-metastasis activities in various cancer cells. However, the detailed impacts and underlying mechanisms of tricetin on human osteosarcoma cell metastasis are still unclear. Here, the hypothesis that tricetin possesses the anti-metastatic effects on human osteosarcoma cells was tested. The effects of tricetin on cell viability, motility, migration, and invasion in human osteosarcoma U2OS and HOS cells were investigated. Gelatin zymography, western blotting, polymerase chain reaction (PCR), and the luciferase assay were used to further explore the underlying mechanisms involved in anti-metastatic effects in U2OS cells. Their results showed that Tricetin, up to 80 μM without cytotoxicity, attenuated U2OS and HOS cells motility, invasiveness, and migration by reducing matrix metalloproteinase (MMP)-9 enzyme activities. In U2OS cells, tricetin decreased MMP-9 protein and mRNA expressions, which was confirmed by real-time PCR. Next, tricetin reduced phosphorylation of p38 and Akt, but no effect on phosphorylation of ERK1/2 and JNK. In conclusion, tricetin possesses the anti-metastatic activity of osteosarcoma cells by transcriptionally repressing MMP-9 via p38 and Akt signaling pathways. This may be potentially useful as anti-metastatic agents for osteosarcoma chemotherapy.

Urinary laminin-γ2 is a novel biomarker of non-muscle invasive urothelial carcinoma

Lack of appropriate biomarkers has hampered early detection of urothelial cancer (UC), therefore, development of biomarkers for its diagnosis at earlier stages is of importance. Laminin‐332 (Ln‐332, formerly Ln‐5), a component of basement membranes, consists of Ln‐α3, Ln‐β3, and Ln‐γ2 polypeptides. However, monomeric Ln‐γ2 alone is frequently expressed in malignant neoplasms. If Ln‐γ2 is also expressed in UC and secreted into the urine, its detection could be useful for UC diagnosis. Here, we evaluated Ln‐γ2 levels from 60 patients with urinary diseases (including UC) by Western blotting, and detected it in approximately 53% of UC cases. Using immunohistochemistry, we confirmed Ln‐γ2 expression in UC tissues that were positive for Ln‐γ2, whereas Ln‐α3 expression was absent. We next developed a sandwich enzyme‐linked immunosorbent assay and applied it for screening 39 patients with non‐muscle invasive UC and 61 patients with benign urologic diseases. The Ln‐γ2 levels were higher in UC patients than in those with benign urologic diseases. Ln‐γ2 was detected even in patients with earlier stages of UC, such as Ta, T1, or carcinoma in situ. The sensitivity of Ln‐γ2 testing for UC was 97.4%, and the specificity was 45.9%, using a cut‐off of 0.5 μg/g∙crn. Ln‐γ2 had greater diagnostic value for detecting non‐muscle invasive UC compared to conventional urine cytology and available biomarkers for UC, and may be useful as a urine biomarker for the diagnosis and monitoring of UC.

Immunoexpression of ROCK-1 and MMP-9 as prognostic markers in breast cancer

Breast cancer is the most common tumor in women and it has high mortality mainly due to the occurrence of tumor metastasis. Both the processes of cell migration and anchorage to the substrate are essential for the development of metastasis. These processes occur by rearrangements of the actin cytoskeleton, regulated by Rho-associated protein kinase 1 (ROCK-1). The degradation of the extracellular matrix, influenced by metalloproteinase 9 (MMP-9) also exerts greater cell invasiveness. The present study evaluated the ROCK-1 and MMP-9 proteins using an immunohistochemical method through the selection of invasive ductal breast carcinoma. The protein expression was correlated to clinicopathological parameters and overall survival of the patients. High expression of the ROCK-1 protein was correlated statistically to the status of lymph nodes (p=0.007) and showed variable expression in different clinical stages of the tumor. MMP-9 showed a strong immunostaining in patients with metastasis that had died, whereas there was no marker in normal breast tissues. In addition, 46.6% of patients classified as poor prognosis showed high expression of ROCK-1 and MMP-9 protein and another 40.0% just showed high expression of MMP-9. Thus, the differential expression of ROCK-1 and MMP-9 proteins suggests their potential use as prognostic markers in breast cancer.

The Complex Interaction of Matrix Metalloproteinases in the Migration of Cancer Cells through Breast Tissue Stroma

Breast cancer mortality is directly linked to metastatic spread. The metastatic cell must exhibit a complex phenotype that includes the capacity to escape from the primary tumour mass, invade the surrounding normal tissue, and penetrate into the circulation before proliferating in the parenchyma of distant organs to produce a metastasis. In the normal breast, cellular structures change cyclically in response to ovarian hormones leading to regulated cell proliferation and apoptosis. Matrix metalloproteinases (MMPs) are a family of zinc dependent endopeptidases. Their primary function is degradation of proteins in the extracellular matrix to allow ductal progression through the basement membrane. A complex balance between matrix metalloproteinases and their inhibitors regulate these changes. These proteinases interact with cytokines, growth factors, and tumour necrosis factors to stimulate branching morphologies in normal breast tissues. In breast cancer this process is disrupted facilitating tumour progression and metastasis and inhibiting apoptosis increasing the life of the metastatic cells. This paper highlights the role of matrix metalloproteinases in cell progression through the breast stroma and reviews the complex relationships between the different proteinases and their inhibitors in relation to breast cancer cells as they metastasise.

Anti-metastatic and anti-tumor growth effects of Origanum majorana on highly metastatic human breast cancer cells: inhibition of NFκB signaling and reduction of nitric oxide production

Background

We have recently reported that Origanummajorana exhibits anticancer activity by promoting cell cycle arrest and apoptosis of the metastatic MDA-MB-231 breast cancer cell line. Here, we extended our study by investigating the effect of O. majorana on the migration, invasion and tumor growth of these cells.

Results

We demonstrate that non-cytotoxic concentrations of O. majorana significantly inhibited the migration and invasion of the MDA-MB-231 cells as shown by wound-healing and matrigel invasion assays. We also show that O. majorana induce homotypic aggregation of MDA-MB-231 associated with an upregulation of E-cadherin protein and promoter activity. Furthermore, we show that O. majorana decrease the adhesion of MDA-MB-231 to HUVECs and inhibits transendothelial migration of MDA-MB-231 through TNF-α-activated HUVECs. Gelatin zymography assay shows that O. majorana suppresses the activities of matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9). ELISA, RT-PCR and Western blot results revealed that O. majorana decreases the expression of MMP-2, MMP-9, urokinase plasminogen activator receptor (uPAR), ICAM-1 and VEGF. Further investigation revealed that O. majorana suppresses the phosphorylation of IκB, downregulates the nuclear level of NFκB and reduces Nitric Oxide (NO) production in MDA-MB-231 cells. Most importantly, by using chick embryo tumor growth assay, we also show that O. majorana promotes inhibition of tumor growth and metastasis in vivo.

Conclusion

Our findings identify Origanummajorana as a promising chemopreventive and therapeutic candidate that modulate breast cancer growth and metastasis.

Exosome-bound WD repeat protein Monad inhibits breast cancer cell invasion by degrading amphiregulin mRNA

Increased stabilization of mRNA coding for key cancer genes can contribute to invasiveness. This is achieved by down-regulation of exosome cofactors, which bind to 3'-UTR in cancer-related genes. Here, we identified amphiregulin, an EGFR ligand, as a target of WD repeat protein Monad, a component of R2TP/prefoldin-like complex, in MDA-MB-231 breast cancer cells. Monad specifically interacted with both the 3'-UTR of amphiregulin mRNA and the RNA degrading exosome, and enhanced decay of amphiregulin transcripts. Knockdown of Monad increased invasion and this effect was abolished with anti-amphiregulin neutralizing antibody. These results suggest that Monad could prevent amphiregulin-mediated invasion by degrading amphiregulin mRNA.

A functional comparison between the HER2(high)/HER3 and the HER2(low)/HER3 dimers on heregulin-β1-induced MMP-1 and MMP-9 expression in breast cancer cells

Overexpression of HER2 correlates with more aggressive tumors and increased resistance to cancer chemotherapy. However, a functional comparison between the HER2^high/HER3 and the HER2^low/HER3 dimers on tumor metastasis has not been conducted. Herein we examined the regulation mechanism of heregulin-β1 (HRG)-induced MMP-1 and -9 expression in breast cancer cell lines. Our results showed that the basal levels of MMP-1 and -9 mRNA and protein expression were increased by HRG treatment. In addition, HRG-induced MMP-1 and -9 expression was significantly decreased by MEK1/2 inhibitor, U0126 but not by phosphatidylinositol 3-kinase (PI-3K) inhibitor, LY294002. To confirm the role of MEK/ERK pathway on HRG-induced MMP-1 and -9 expression, MCF7 cells were transfected with constitutively active adenoviral-MEK (CA-MEK). The level of MMP-1 and -9 expressions was increased by CA-MEK. MMP-1 and -9 mRNA and protein expressions in response to HRG were higher in HER2 overexpressed cells than in vector alone. The phosphorylation of HER2, HER3, ERK, Akt, and JNK were also significantly increased in HER2 overexpressed MCF7 cells compared with vector alone. HRG-induced MMP-1 and -9 expressions were significantly decreased by lapatinib, which inhibits HER1 and HER2 activity, in both vector alone and HER2 overexpressed MCF7 cells. Finally, HRG-induced MMP-1 and MMP-9 expression was decreased by HER3 siRNA overexpression. Taken together, we suggested that HRG-induced MMP-1 and MMP-9 expression is mediated through HER3 dependent pathway and highly expressed HER2 may be associated with more aggressive metastasis than the low expressed HER2 in breast cancer cells.

Identification of function for CD44 intracytoplasmic domain (CD44-ICD): modulation of matrix metalloproteinase 9 (MMP-9) transcription via novel promoter response element

CD44 is a multifunctional cell receptor that conveys a cancer phenotype, regulates macrophage inflammatory gene expression and vascular gene activation in proatherogenic environments, and is also a marker of many cancer stem cells. CD44 undergoes sequential proteolytic cleavages that produce an intracytoplasmic domain called CD44-ICD. However, the role of CD44-ICD in cell function is unknown. We take a major step toward the elucidation of the CD44-ICD function by using a CD44-ICD-specific antibody, a modification of a ChIP assay to detect small molecules, and extensive computational analysis. We show that CD44-ICD translocates into the nucleus, where it then binds to a novel DNA consensus sequence in the promoter region of the MMP-9 gene to regulate its expression. We also show that the expression of many other genes that contain this novel response element in their promoters is up- or down-regulated by CD44-ICD. Furthermore, hypoxia-inducible factor-1α (Hif1α)-responsive genes also have the CD44-ICD consensus sequence and respond to CD44-ICD induction under normoxic conditions and therefore independent of Hif1α expression. Additionally, CD44-ICD early responsive genes encode for critical enzymes in the glycolytic pathway, revealing how CD44 could be a gatekeeper of the Warburg effect (aerobic glycolysis) in cancer cells and possibly cancer stem cells. The link of CD44 to metabolism is novel and opens a new area of research not previously considered, particularly in the study of obesity and cancer. In summary, our results finally give a function to the CD44-ICD and will accelerate the study of the regulation of many CD44-dependent genes.

Matrix metalloproteinase 3 is a mediator of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) may be triggered by epithelial injury that results in aberrant production of growth factors, cytokines, and proteinases, leading to proliferation of myofibroblasts, excess deposition of collagen, and destruction of the lung architecture. The precise mechanisms and key signaling mediators responsible for this aberrant repair process remain unclear. We assessed the importance of matrix metalloproteinase-3 (MMP-3) in the pathogenesis of IPF through i) determination of MMP-3 expression in patients with IPF, ii) in vivo experiments examining the relevance of MMP-3 in experimental models of fibrosis, and iii) in vitro experiments to elucidate possible mechanisms of action. Gene expression analysis, quantitative RT-PCR, and Western blot analysis of explanted human lungs revealed enhanced expression of MMP-3 in IPF, compared with control. Transient adenoviral vector-mediated expression of recombinant MMP-3 in rat lung resulted in accumulation of myofibroblasts and pulmonary fibrosis. Conversely, MMP-3-null mice were protected against bleomycin-induced pulmonary fibrosis. In vitro treatment of cultured lung epithelial cells with purified MMP-3 resulted in activation of the β-catenin signaling pathway, via cleavage of E-cadherin, and induction of epithelial-mesenchymal transition. These processes were inhibited in bleomycin-treated MMP-3-null mice, as assessed by cytosolic translocation of β-catenin and cyclin D1 expression. These observations support a novel role for MMP-3 in the pathogenesis of IPF, through activation of β-catenin signaling and induction of epithelial-mesenchymal transition.

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

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

ERK/MAPK pathways play critical roles in EGFR ligands-induced MMP1 expression

Activation of epidermal growth factor receptor (EGFR)-induced signaling pathways has been correlated with tumor progression, invasion and metastasis in a variety of cancers including breast carcinoma, but the underlying mechanism is not well understood. Matrix metalloproteinases (MMPs) have been implicated in cancer invasion and metastasis for their extracellular matrix (ECM)-proteolytic activity. However, the correlation of EGFR pathway with MMP expression in breast cancer has not been established. The aim of this study was to elucidate the interaction between EGFR ligands and their signaling pathway and MMP expression which might be closely related with breast cancer pathogenesis. We investigated the effect of EGF ligands on the MMP1 expression in SK-BR3 cell lines using RT-PCR, Western blot, ELISA and EMSA. Treatments with EGFR ligands, EGF and TGF-α enhanced MMP1 expression at the level of both transcription and translation in SK-BR3 breast cancer cells. EGF and TGF-α treatment resulted in phosphorylation of EGFR, and consequent activation of ERK1/2 pathway. Tyrosine kinase inhibitors of HER family, erlotinib, lapatinib and canertinib suppressed EGF-ligands mediated MMP1 overexpression. The specific MEK inhibitor, U0126, significantly blocks EGF and TGF-α-mediated ERK1/2 activation and subsequent MMP1 induction in SK-BR3 cells. Inhibition of the Akt pathway with LY294002 paradoxically augmented MMP1 expression by reciprocal activation of ERK1/2 pathway. These data suggest that invasive potential of SK-BR3 cell would be affected by these drugs by suppression of EGFR ligands-induced MMP1 expression.

Expression of matrix metalloproteinases (MMPs) in primary human breast cancer and breast cancer cell lines: New findings and review of the literature

BACKGROUND

Matrix metalloproteinases (MMPs) are a family of structural and functional related endopeptidases. They play a crucial role in tumor invasion and building of metastatic formations because of their ability to degrade extracellular matrix proteins. Under physiological conditions their activity is precisely regulated in order to prevent tissue disruption. This physiological balance seems to be disrupted in cancer making tumor cells capable of invading the tissue. In breast cancer different expression levels of several MMPs have been found.

METHODS

To fill the gap in our knowledge about MMP expression in breast cancer, we analyzed the expression of all known human MMPs in a panel of twenty-five tissue samples (five normal breast tissues, ten grade 2 (G2) and ten grade 3 (G3) breast cancer tissues). As we found different expression levels for several MMPs in normal breast and breast cancer tissue as well as depending on tumor grade, we additionally analyzed the expression of MMPs in four breast cancer cell lines (MCF-7, MDA-MB-468, BT 20, ZR 75/1) commonly used in research. The results could thus be used as model for further studies on human breast cancer. Expression analysis was performed on mRNA and protein level using semiquantitative RT-PCR, Western blot, immunohistochemistry and immunocytochemistry.

RESULTS

In summary, we identified several MMPs (MMP-1, -2, -8, -9, -10, -11, -12, -13, -15, -19, -23, -24, -27 and -28) with a stronger expression in breast cancer tissue compared to normal breast tissue. Of those, expression of MMP-8, -10, -12 and -27 is related to tumor grade since it is higher in analyzed G3 compared to G2 tissue samples. In contrast, MMP-7 and MMP-27 mRNA showed a weaker expression in tumor samples compared to healthy tissue. In addition, we demonstrated that the four breast cancer cell lines examined, are constitutively expressing a wide variety of MMPs. Of those, MDA-MB-468 showed the strongest mRNA and protein expression for most of the MMPs analyzed.

CONCLUSION

MMP-1, -2, -8, -9, -10, -11, -12, -13, -15, -19, -23, -24, -27 and -28 might thus be associated with breast cancer development and tumor progression. Therefore, these MMPs are proper candidates for further functional analysis of their role in breast cancer.

Matrix metalloproteinase-2 polymorphisms and breast cancer susceptibility

Matrix metalloproteinase-2 (MMP-2) is a well-known mediator of cancer metastasis but is also thought to be involved in several aspects of cancer development, including cell growth and inflammation. We comprehensively characterized genetic variation across the MMP-2 gene and evaluated associations with breast cancer risk using a two-phase (phase 1 and phase 2) study design. A total of 39 polymorphisms were genotyped among 6,066 Chinese women participating in the Shanghai Breast Cancer Study, a population-based case-control study. Two MMP-2 promoter polymorphisms were found to have consistent results between phase 1 and phase 2 participants, and to be significantly associated with breast cancer risk among all genotyped participants. Minor allele homozygotes for rs11644561 (G/A) were found to have a decreased risk of breast cancer [odds ratio (OR), 0.6; 95% confidence interval (CI), 0.3-1.0] compared with major allele homozygotes, as were minor allele homozygotes for rs11643630 (T/G) compared with major allele homozygotes (OR, 0.8; 95% CI, 0.7-1.0). When analyzed together, a rare haplotype (4.4%) with both rs11644561 A and rs11643630 G was found to have a significantly reduced risk of breast cancer (OR, 0.6; 95% CI, 0.4-0.8). In addition, rare allele homozygotes for rs243865 (-1306 C/T) tended to have an increased risk of breast cancer (OR, 1.4; 95% CI, 0.9-2.4). Together, these findings support a role for MMP-2 genetic variation in breast cancer susceptibility.

Prognostic significance of MMP-9 and TIMP-1 serum and tissue expression in breast cancer

Tumor progression and metastasis contribute to the great majority of breast cancer deaths. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are thought to be involved in tumor progression and metastasis. Thus, we determined whether the expression of MMP-9 and TIMP-1 is associated with prognosis in breast cancer patients. We measured serum MMP-9 and TIMP-1 by enzyme-linked immunosorbent assay in 60 breast cancer patients, 18 benign breast disease patients and 15 healthy controls. We also evaluated the expression of MMP-9 and TIMP-1 protein and mRNA in paraffin-embedded tumor tissues from the 60 breast cancer patients by immunohistochemistry and in situ hybridization. We then correlated serum and tissue levels of MMP-9 and TIMP-1 in breast cancer samples and their expression with patients' clinicopathologic characteristics. We found that serum levels of MMP-9 and TIMP-1 were significantly higher in breast cancer patients than in benign breast disease and in healthy controls. High serum levels of MMP-9 and TIMP-1 were associated with lymph node metastasis, higher tumor stage and lower relapse-free and overall survival (OS) rates. Compared to low expression, high tissue expression of MMP-9 protein was associated with lymph node metastasis and higher tumor stage; and high tissue expression of TIMP-1 was associated with a lower OS rate. Our findings suggest that MMP-9 and TIMP-1 may further be evaluated as biomarkers for predicting progression and prognosis of breast cancer.

PEGylated DX-1000: pharmacokinetics and antineoplastic activity of a specific plasmin inhibitor

Novel inhibitors of the urokinase-mediated plasminogen (plg) activation system are potentially of great clinical benefit as anticancer treatments. Using phage display, we identified DX-1000 a tissue factor pathway inhibitor-derived Kunitz domain protein which is a specific high-affinity inhibitor of plasmin (pln) (K(i) = 99 pM). When tested in vitro, DX-1000 blocks plasmin-mediated pro-matrix metalloproteinase-9 (proMMP-9) activation on cells and dose-dependently inhibits tube formation, while not significantly affecting hemostasis and coagulation. However, this low-molecular weight protein inhibitor ( approximately 7 kDa) exhibits rapid plasma clearance in mice and rabbits, limiting its potential clinical use in chronic diseases. After site-specific PEGylation, DX-1000 retains its activity and exhibits a decreased plasma clearance. This PEGylated derivative is effective in vitro, as well as potent in inhibiting tumor growth of green fluorescent protein (GFP)-labeled MDA-MB-231 cells. 4PEG-DX-1000 treatment causes a significant reduction of urokinase-type plasminogen activator (uPA) and plasminogen expressions, a reduction of tumor proliferation, and vascularization. 4PEG-DX-1000 treatment significantly decreases the level of active mitogen-activated protein kinase (MAPK) in the primary tumors and reduces metastasis incidence. Together, our results demonstrate the potential value of plasmin inhibitors as therapeutic agents for blocking breast cancer growth and metastasis.

COUP-TFI modulates estrogen signaling and influences proliferation, survival and migration of breast cancer cells

We previously showed that COUP-TFI interacts with the Estrogen Receptor alpha (ER alpha) to recruit Extracellular signal Regulated Kinases (ERKs) in an Estradiol (E2)-independent manner, resulting in an enhancement of ER alpha transcriptional activity. However, the involvement of COUP-TFI in physiologically relevant functions of ER alpha, such as the mitogenic activity that E2 has on breast cancer cells, remains poorly understood. Here, we first showed that the amounts of COUP-TFI protein are higher in dedifferentiated mammary cell lines (MDA-MB-231) and tumor breast cells as compared to the differentiated MCF-7 cell line and normal breast cells. To evaluate the functional relevance of the COUP-TFI/ER alpha interplay in mammary cells, we generated MCF-7 cells that stably over-express COUP-TFI. We found that the over-expression of COUP-TFI enhances motility and invasiveness of MCF-7 cells. COUP-TFI also promotes the proliferation of MCF-7 cells through ER alpha-dependent mechanisms that target cell cycle progression and cell survival. To further investigate the mechanisms underlying these effects of COUP-TFI, we evaluated the expression of known E2-target genes in breast cancer, and found that COUP-TFI differentially regulated genes involved in cell proliferation, apoptosis, and migration/invasion. Notably, Cathepsin D (CTSD) transcript and protein levels were significantly higher in presence and absence of E2 in MCF-7 over-expressing COUP-TFI. Chromatin Immunoprecipitation assays showed that ER alpha, phospho-RNA Polymerase II, as well as p68 RNA Helicase, a phospho-Serine 118 dependent co-activator of ER alpha, were preferentially recruited onto the CTSD gene proximal promoter in COUP-TFI over-expressing cells. These results suggest that COUP-TFI selectively regulates the expression of endogenous E2-target genes and consequently modifies ER alpha positive mammary cells response to E2.

Characterisation of two rat mammary tumour models for breast cancer research by gene expression profiling

Breast cancer is the most frequently occurring cancer in women. Treatment options are still an active area of research. Models used for this purpose include induced models in rodents. By the advent of microarrays it has become possible to evaluate models not only for similar morphology or selected markers by polymerase chain reaction (PCR) or immunohistochemistry but also for the expression of thousands of genes at once. This study presents gene expression profiles of the hormone-sensitive 7,12-dimethylbenzanthracene-induced and the metastasising MTLn3-model. The models are discussed for their relevance to breast cancer in humans.

HRPAP20: a novel calmodulin-binding protein that increases breast cancer cell invasion

We previously reported the identification of HRPAP20 (hormone-regulated proliferation-associated protein 20), a novel hormone-regulated, proliferation-associated protein. In tumor cell lines, constitutive HRPAP20 expression enhanced proliferation and suppressed apoptosis, characteristics frequently associated with malignant progression. Here, we report that highly invasive breast cancer cell lines and human breast tumor specimens express elevated HRPAP20, which in transfection experiments in MCF-7 and MDA-MB-231 cells, increased invasion. Results from mechanistic studies revealed that HRPAP20 bound to calmodulin (CaM) via a conserved CaM-binding motif. Transfection of MCF-7 breast cancer cells with HRPAP20 harboring a mutated CaM-binding motif (HRPAP20K73A) inhibited its interaction with CaM and failed to increase invasion. Other experiments revealed that transfection with HRPAP20, but not HRPAP20K73A, increased secretion of matrix metalloproteinase-9 (MMP-9). Moreover, knockdown of HRPAP20 with small interfering RNA in MCF-7/HRPAP20 transfectants and wild-type MDA-MB-231 cells reduced invasion and inhibited secretion of MMP-9. Together these observations suggest that HRPAP20 may be an important regulator of breast tumor cell invasion by a CaM-mediated mechanism that leads to increased MMP-9 secretion. We conclude that dysregulation of HRPAP20 expression in tumor cells may contribute to the observed phenotypic changes associated with breast cancer progression.

MMP-9 and MMP-2 gelatinases and TIMP-1 and TIMP-2 inhibitors in breast cancer: correlations with prognostic factors

The goal of our study was to analyse the prognostic values for some matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in breast cancer. We evaluated the activity and the expression levels of MMP-9, MMP-2, TIMP-1 and TIMP-2 in malignant versus benign fresh breast tumor extracts. For this purpose, gelatinzymography, immunoblotting and ELISA were used to analyse the activity and expression of MMPs and TIMPs. We found that MMP-9 expression level and activity are increased in malignant tumors. In addition, MMP-9/TIMP-1 and MMP-2/TIMP-2 ratio values obtained by us were significantly different in malignant tumors compared to benign tumors. We suggest that the abnormal MMP-9/TIMP-1 balance plays a role in the configuration of breast invasive carcinoma of no special type and also in tumor growth, while altered MMP-2/TIMP-2 ratio value could be associated with lymph node invasion and used as a prognostic marker in correlation with Nottingham Prognostic Index. Finally, we showed that in malignant tumors high expression of estrogen receptors is associated with enhanced activity of MMP-2 and increased bcl- 2 levels, while high expression of progesterone receptors is correlated with low TIMP-1 protein levels.

Relationships between the level of matrix metalloproteinase-2 and tumor size of breast cancer

BACKGROUND

The involvements of matrix metalloproteinase-2 (MMP-2) in the pathogenesis of breast cancers have been established. We determined the concentrations of MMP-2 in serum samples and tumor tissues of breast cancer patients.

METHODS

Gelatin zymography and ELISA were used to measure MMP-2 and MMP-9 concentrations in 90 breast cancer patients, including 60 tissue samples and 30 serum samples.

RESULTS

ProMMP-2, activated MMP-2, proMMP-9 and activated MMP-9 levels were significantly higher in tumor tissues than that of corresponding paired adjacent normal tissue of 60 breast cancer patients (p<0.01). Further linear regression analysis has showed that the tumor size positively correlated with MMP-2 level in tumor tissue samples (R=0.55, p<0.0001), as well as with that of in serum samples (R=0.398, p=0.032). In addition, further statistical analysis for clinic pathological parameters revealed that MMP-2 level was significantly increased in patients with metastasis (p<0.05). Furthermore, MMP-2 level was significantly different between tumor grades (p=0.006).

CONCLUSIONS

MMP-2 levels in serum and tumor tissue might reflect the severity of invasion of breast cancer and various MMP inhibitors might be selectively used as potential anti-metastasis agents according to tumor size.

ETS transcription factors and their emerging roles in human cancer

Cancer can be defined as a genetic disease, resulting as a consequence of multiple events associated with initiation, promotion and metastatic growth. Cancer results from the loss of control of cellular homeostasis. Cell homeostasis is the result of the balance between proliferation and cell death, while cellular transformation can be viewed as a loss of relationship between these events. Oncogenes and tumour suppressor genes act as modulators of cell proliferation, while the balance of apoptotic and anti-apoptotic genes controls cell death. All cancer cells acquire similar sets of functional capacities: (1) independence from mitogenic/growth signals; (2) loss of sensitivity to "anti-growth" signals; (3) evade apoptosis; (4) Neo-angiogenic conversion; (5) release from senescence; and (6) invasiveness and metastasis. One of the goals of molecular biology is to elucidate the mechanisms that contribute to the development and progression of cancer. Such understanding of the molecular basis of cancer will provide new possibilities for: (1) earlier detection as well as better diagnosis and staging of disease with detection of minimal residual disease recurrences and evaluation of response to therapy; (2) prevention; and (3) novel treatment strategies. We feel that increased understanding of ETS-regulated biological pathways will directly impact these areas. ETS proteins are transcription factors that activate or repress the expression of genes that are involved in various biological processes, including cellular proliferation, differentiation, development, transformation and apoptosis. Identification of target genes that are regulated by a specific transcription factor is one of the most critical areas in understanding the molecular mechanisms that control transcription. Furthermore, identification of target gene promoters for normal and oncogenic transcription factors provides insight into the regulation of genes that are involved in control of normal cell growth, and differentiation, as well as provide information critical to understanding cancer development. This review will highlight the current understanding of ETS genes and their role in cancer.

Expression of matrix metalloproteinase (MMP)-2 and MMP-9 in breast cancer with a special reference to activator protein-2, HER2, and prognosis

PURPOSE

In the present study, we investigated the expression and prognostic value of matrix metalloproteinase (MMP)-2 and MMP-9 in breast cancer as well as their relation to transcription factor activator protein (AP)-2 and HER2 oncogene. The role of invasion and metastasis-promoting MMPs and their potential regulators, AP-2 and HER2, is currently still unclear in breast cancer.

EXPERIMENTAL DESIGN

MMP-2 and MMP-9 expressions were analyzed immunohistochemically in a large prospective series of 421 breast cancer patients diagnosed and treated between 1990 and 1995 at Kuopio University Hospital (Kuopio, Finland). The relation of MMP-2 and MMP-9 expressions to AP-2, HER2, clinicopathological data, and survival was investigated.

RESULTS

Both MMP-2 and MMP-9 were expressed in the cytoplasm of malignant and stromal cells. High expression of MMPs in carcinoma cells was related to small tumors (T1, stage I), whereas positive stromal expression of MMPs was associated with aggressive factors. High expression of MMP-2 and MMP-9 in carcinoma cells, but not in stromal cells, was related to high AP-2 expression. Positive stromal MMP-2 expression was associated with HER2 overexpression in the whole patient group and in the node-negative patient subgroup. Positive stromal MMP-9 expression was related to HER2 overexpression in estrogen receptor (ER)-positive disease. In the univariate survival analysis, positive stromal MMP-9 predicted shorter recurrence-free survival (RFS; P=0.0389) and breast cancer-related survival (BCRS; P=0.0081) in ER+ disease, especially in the subgroup of ER+ tumors of < or =2 cm in diameter (T1; P=0.0031 for RFS, and P=0.0089 for BCRS). High MMP-9 expression in cancer cells predicted longer RFS (P=0.0351) in the whole patient group. In the multivariate analysis of the whole patient group, the independent predictors of shorter RFS were reduced MMP-9 expression in carcinoma cells (P=0.0248), HER2 overexpression (P=0.0001), and advanced-stage disease (P=0.0002). Shorter BCRS was predicted by advanced-stage disease (P <0.0001).

CONCLUSIONS

Expression of MMP-2 and MMP-9 in breast cancer seems to be partly related to expression of AP-2 and HER2. Positive stromal MMP-9 expression predicts poor survival in the hormone-responsive small tumors, whereas MMP-9 expression in carcinoma cells favors survival. Evaluation of MMP-9 expression seems to add valuable information on breast cancer prognosis.

Inflammatory regulation of extracellular matrix remodeling in calcific aortic valve stenosis

BACKGROUND

Calcific aortic stenosis (AS), the most frequent heart valve disorder in developed countries, leads to the calcification and fibrous thickening of the valve. While several studies have addressed the process of valvular calcification, the molecular pathomechanisms of the extensive matrix remodeling remain unclear. Because inflammation is present in stenotic valves, we hypothesized that the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) might influence cell proliferation and regulate the expression and activation of matrix metalloproteinases (MMPs)--enzymes that are thought to be involved in calcific AS.

METHODS

Immunohistochemistry for leukocytes, TNFalpha, MMP-1, and the endogenous MMP inhibitor tissue inhibitor of metalloproteinase (TIMP)-1 was performed on human stenotic (n = 19) and control (n = 8) valves. Primary cultures of human aortic valve myofibroblasts were incubated with and without TNFalpha, and cell proliferation was assessed. The expression and activation of MMP-1 were detected by Western blotting and a specific MMP-1 activity assay.

RESULTS

Control valves showed scattered macrophages and low expression of TNFalpha, MMP-1, and TIMP-1. In stenotic valves, leukocyte infiltration and a strong, colocalized expression of TNFalpha and MMP-1 were present, while TIMP-1 remained unchanged. Double-label immunofluorescence localized TNFalpha mainly to macrophages. In cultured human aortic valve myofibroblasts, TNFalpha stimulated proliferation and induced a time-dependent increase in MMP-1 expression and activation, while TIMP-1 remained unchanged.

CONCLUSION

The results indicate that matrix remodeling in calcific AS involves the expression and activation of MMPs. Activated leukocytes, by the secretion of TNFalpha, may stimulate valvular myofibroblasts to proliferate and express MMPs, thus regulating actively the matrix remodeling in calcific AS.

ETS transcription factors and targets in tumour invasion, angiogenesis and bone metastasis

The ETS gene family encodes unique transcription regulators that have a common ETS DNA binding domain. At least 25 distinct ETS related genes have been isolated from various species. The ETS family transcription factors are known to regulate genetic programs essential for differentiation and development processes and play diverse roles in a number of biological processes such as organogenesis and tissue remodelling during murine development, hematopoiesis, B-cell development, activation of T-cells and signal transduction, as well as osteogenesis, osteoblast differentiation and extracellular matrix mineralization. Based on the observation of overexpression of ETS related genes in various primary and metastatic tumors, their utility as potential therapeutic targets has been suggested. Antisense oligonucleotides, transdominant, and dominant-negative mutants have been exploited to target and inhibit ETS gene expression selectively. These ETS-targeted studies are being pursued to assess their antitumour effect, and hold the potential that such specific ETS-targeted inhibitors may become a viable option for cancer therapy. Collectively, these studies also demonstrate that Ets factors can regulate multiple aspects of the malignant phenotype of many tumor cells in particular neoangiogenesis and extracellular matrix-regulated (ECM-regulated) cell proliferation, motility and invasiveness.

Preoperative serum MMP-9 immunoreactive protein is a prognostic indicator for relapse-free survival in breast carcinoma

The immunoreactive protein for the matrix metalloproteinase-9 (MMP-9) was studied prospectively from the pre-treatment sera of breast carcinoma patients using an enzyme-linked immunoassay (ELISA). The study comprised 71 primary breast carcinoma patients treated in Oulu University Hospital, Finland, between 1988 and 1991. The median follow-up time was over 10 years. Low preoperative serum MMP-9 (<54.5 ng/ml) was found to correlate with a poor relapse-free survival (RFS) in primary breast carcinoma. After 10 years of follow-up only 43% of the patients with low serum MMP-9 were disease-free, whereas 76% of the patients with high serum MMP-9 lived free of the disease (log-rank P=0.008). Low serum MMP-9 also indicated poor RFS in node-negative (P=0.03), stage I-II (P=0.01), progesterone receptor negative (P=0.008) carcinoma as well as in patients <50 years (P=0.02) with primary breast carcinoma. There was no statistical difference in overall survival. In multivariate analysis, preoperative low serum MMP-9 increases the risk of relapse 3.0-fold during the first 10 years of follow-up in primary breast carcinoma.

Integrin Fibronectin Receptors in Matrix Metalloproteinase-1–Dependent Invasion by Breast Cancer and Mammary Epithelial Cells

Integrins contribute to progression in many cancers, including breast cancer. For example, the interaction of alpha(5)beta(1) with plasma fibronectin causes the constitutive invasiveness of human prostate cancer cells. Inhibition of this process reduces tumorigenesis and prevents metastasis and recurrence. In this study, naturally serum-free basement membranes were used as invasion substrates. Immunoassays were used to compare the roles of alpha(5)beta(1) and alpha(4)beta(1) fibronectin receptors in regulating matrix metalloproteinase (MMP)-1-dependent invasion by human breast cancer and mammary epithelial cells. We found that a peptide consisting of fibronectin PHSRN sequence, Ac-PHSRN-NH(2), induces alpha(5)beta(1)-mediated invasion of basement membranes in vitro by human breast cancer and mammary epithelial cells. PHSRN-induced invasion requires interstitial collagenase MMP-1 activity and is suppressed by an equimolar concentration of a peptide consisting of the LDV sequence of the fibronectin connecting segment, Ac-LHGPEILDVPST-NH(2), in mammary epithelial cells, but not in breast cancer cells. This sequence interacts with alpha(4)beta(1), an integrin that is often down-regulated in breast cancer cells. Immunoblotting shows that the PHSRN peptide stimulates MMP-1 production by serum-free human breast cancer and mammary epithelial cells and that the LDV peptide represses PHSRN-stimulated MMP-1 production only in mammary epithelial cells. Furthermore, PHSRN stimulates MMP-1 activity in breast cancer cells and mammary epithelial cells with a time course that closely parallels invasion induction. Thus, down-regulation of surface alpha(4)beta(1) during oncogenic transformation may be crucial for establishment of the alpha(5)beta(1)-induced, MMP-1-dependent invasive phenotype of breast cancer cells.

A Molecular Basis for the Selectivity of Thiadiazole Urea Inhibitors with Stromelysin-1 and Gelatinase-A from Generalized Born Molecular Dynamics Simulations

Matrix metalloproteinases (MMPs) represent a potentially important class of therapeutic targets for the treatment of diseases such as cancer. Selective inhibition of MMPs will be required given the high sequence identity across the family and the discovery that individual MMPs also regulate the natural angiogenesis inhibitor angiostatin. In this study, we have used computational methods to model the selectivity for six thiadiazole urea inhibitors with stromelysin-1 and gelatinase-A, two homologous MMPs that have been implicated in breast cancer. From continuum Generalized Born molecular dynamics (GB-MD) and MM-GBSA analysis, we estimated ligand free energies of binding using 200 snapshots obtained from a short 40 ps simulation of the relevant protein-ligand complex. The MM-GBSA free energies, computed from the continuum GB-MD trajectories, show strong correlation with the experimental affinities (r(2) = 0.74); prior studies have employed explicit water MD simulations. Including estimates for changes in solute entropy in the binding calculations slightly diminishes the overall correlation with experiment (r2 = 0.71). Notably, in every case, the simulation results correctly predict that a given ligand will bind selectively to stromelysin-1 over gelatinase-A which is gratifying given the high degree of structural homology between the two proteins. The increased selectivity for stromelysin-1 appears to be driven by (1) increased favorable van der Waals interactions, (2) increased favorable Coulombic interactions, and (3) decreased unfavorable total electrostatic energies (Coulombic plus desolvation).

Multiple Aspects of the Phenotype of Mammary Epithelial Cells Transformed by Expression of Activated M-Ras Depend on an Autocrine Mechanism Mediated by Hepatocyte Growth Factor/Scatter Factor

Multiple aspects of the transformed phenotype induced in a murine mammary epithelial cell line scp-2 by expression of activated G22V M-Ras, including maintainance of cell number at low density, anchorage-independent growth, invasion of Matrigel, and secretion of matrix metalloproteinases (MMP) 2 and 9, were dependent on an autocrine mechanism. Conditioned medium from dense cultures of scp-2 cells expressing G22V M-Ras, but not from parental cells, induced activation of Erk and Akt in cells expressing G22V M-Ras, maintained the cell number and promoted anchorage-independent growth of cells expressing G22V M-Ras (although not the parental cells), and induced scattering of MDCK cells. The latter activities were blocked by neutralizing antibodies to hepatocyte growth factor/scatter factor (HGF/SF) and could be mimicked by HGF/SF. Anti-HGF/SF antibodies also inhibited invasion of Matrigel, and the production of MMP-2 and MMP-9, together with urokinase-type plasminogen activator, was secreted by G22V M-Ras scp-2 cells but not by parental cells. Invasion of Matrigel was blocked by an inhibitor of MMPs, BB94, and by the mitogen-activated protein kinase kinase 1/2 kinase inhibitor PD98059 but was only marginally affected by the phosphatidylinositol 3-kinase inhibitor LY294002. Autocrine HGF/SF was thus critical for expression of key features of the phenotype of mammary epithelial cells transformed by expression of activated M-Ras.

Unopposed matrix metalloproteinase-9 expression in human tuberculous granuloma and the role of TNF-alpha-dependent monocyte networks

Tuberculosis is characterized by granuloma formation and caseous necrosis, but the factors causing tissue destruction are poorly understood. Matrix metalloproteinase (MMP)-9 (92-kDa gelatinase) secretion from monocytes is stimulated by Mycobacterium tuberculosis (M. tb) and associated with local tissue injury in tuberculosis patients. We demonstrate strong immunohistochemical MMP-9 staining in monocytic cells at the center of granuloma and adjacent to caseous necrosis in M. tb-infected patient lymph nodes. Minimal tissue inhibitor of MMPs-1 staining indicated that MMP-9 activity is unopposed. Because granulomas characteristically contain few mycobacteria, we investigated whether monocyte-monocyte cytokine networks amplify MMP-9 secretion. Conditioned medium from M. tb-infected primary human monocytes or THP-1 cells (CoMTB) stimulated MMP-9 gene expression and a >10-fold increase in MMP-9 secretion by monocytes at 3-4 days (p < 0.009, vs controls). Although CoMTB stimulated dose-dependent MMP-9 secretion, MMP-1 (52-kDa collagenase) was not induced. Anti-TNF-alpha Ab but not IL-1R antagonist pretreatment decreased CoMTB-induced MMP-9 secretion by 50% (p = 0.0001). Anti-TNF-alpha Ab also inhibited MMP-9 secretion from monocytic cells by 50%, 24 h after direct M. tb infection (p = 0.0002). Conversely, TNF-alpha directly stimulated dose-dependent MMP-9 secretion. Pertussis toxin inhibited CoMTB-induced MMP-9 secretion and enhanced the inhibitory effect of anti-TNF-alpha Ab (p = 0.05). Although chemokines bind to G protein-linked receptors, CXCL8, CXCL10, CCL2, and CCL5 did not stimulate monocyte MMP-9 secretion. However, the response to cholera toxin confirmed that G protein signaling pathways were intact. In summary, MMP-9 within tuberculous granuloma is associated with tissue destruction, and TNF-alpha, critical for antimycobacterial granuloma formation, is a key autocrine and paracrine regulator of MMP-9 secretion.

Involvement of the plasminogen activation system in cow endometritis

The objectives of this study were to investigate the: (a) presence and activity of components of the "plasminogen activators/plasmin" system in dairy cows with or without endometritis; (b) variations in enzyme activity according to the degree of endometritis; and (c) associations between these enzymes and changes in endometrial histology after intrauterine antibiotic treatment. Endometrial biopsies were collected from anestrus (no palpable ovarian structures and milk progesterone <1 ng/ml) Holstein cows, 30-40 days postpartum. On the basis of a vaginoscopic examination, rectal palpation of the cervix and uterus, and endometrial histology, there were 92 cows with endometritis and 20 cows without endometritis. After biopsy collection, each cow was given an intrauterine infusion of 1.5x10(6) IU of procaine penicillin G. In cows with endometritis, genital tract examinations and biopsies were repeated 2 weeks later. Both plasminogen activators (PAs), tissue type (t-PA) and urokinase (u-PA), were immunologically identified in all uterine biopsies. Plasminogen activator activity (PAA) increased, whereas plasminogen activator inhibition (PAI) and plasmin inhibition (PI) decreased in proportion to the degree of inflammation. Two weeks after intrauterine treatment, PAA had decreased significantly in all cows that had reduced severity of endometrial inflammation and had increased significantly in all cows with increased severity of inflammation. The change in the degree of inflammation depended upon plasminogen activator activity; cows with higher PAA were more likely to improve. In conclusion, there was evidence for a role of the plasminogen activation proteolytic system in bovine endometritis.

Matrix metalloproteinase-2 (MMP-2) is associated with survival in breast carcinoma

Adjuvant therapy is one of the major advances in the treatment of breast carcinoma patients – but do all patients need it? New predictive markers, which are able to save breast carcinoma patients from the most toxic adjuvant therapies, are still needed. The expression of matrix metalloproteinases (MMP-2) has been previously linked to invasiveness of carcinoma cells. In this study, we explored the role of MMP-2 as a prognostic factor in breast carcinoma in a large series to be able to show the favourable effect of MMP-2 negativity in poor prognosis subgroup of hormone receptor-negative patients. The MMP-2 immunoreactive protein was evaluated from primary adenocarcinoma of the breast in 453 cases by using a specific monoclonal antibody in immunohistochemical stainings. The MMP-2 protein found in breast carcinoma tumour cells was here shown to be associated with a shortened recurrence-free survival or relative overall survival (P=0.03). It was shown here that MMP-2 negativity is significantly linked to favourable prognosis in patients considered to be at risk due to their hormone receptor negativity. In the patient group presenting with a progesterone receptor-negative tumour, the survival rate of the MMP-2-positive cases was 58% while it was 95% in MMP-2-negative cases after 10 years of follow-up (P=0.005). The present data shows for the first time that MMP-2 negativity could serve as a marker for favourable prognosis in breast carcinoma patients with a hormone receptor-negative tumour usually associated with high risk. MMP-2 is also shown to correlate to shortened survival independent of major prognostic indicators in patients with primary breast carcinoma.

The favorable prognostic impact of tissue inhibitor of matrix metalloproteinases-1 protein overexpression in breast cancer cells

The tissue inhibitor of metalloproteinases-1 (TIMP1) inhibits tumor cell invasion and metastasis in experimental models; in addition, TIMP1 is supposed to possess another important function, cell growth promotion. The potential prognostic significance of TIMP1 in breast cancer remains unclear. We evaluated the significance of the immunohistochemical expression of TIMP1 in a well-documented series of 133 infiltrating breast carcinomas by examining any possible statistical association between this expression and numerous clinicopathological parameters as well as patients' disease-free interval. TIMP1 was generally expressed in both stromal and cancer cells in our specimens. TIMP1 was overexpressed in cancer cells of 60.15% of all cases. Tumors of high histological and nuclear grade were found to overexpress TIMP1 less frequently than the rest (p=0.003 and p=0.057, respectively). Interestingly, TIMP1 overexpression was inversely associated with cell proliferation, the latter being evidenced by Ki67 immunoreactivity (p=0.028). TIMP1 immunostaining was in parallel with metalloproteinase-2 (MMP2) immunoexpression in both cancer and stromal cells. Multivariate analysis disclosed that TIMP1 overexpression in cancer cells was an independent determining factor for prognosis (p=0.006); TIMP1 overexpression in malignant cells appeared to correlate with favorable outcome, particularly in patients with lack of nodal metastases and in patients with MMP2-negative immunophenotype (p=0.0252). The upregulation of TIMP1 cancer cell expression in breast cancer may suggest that this marker has a multifunctional role apart from that of metalloproteinase inhibitor since it was found to be related to malignant cells' differentiation and proliferation. TIMP1 overexpression in cancer cells appears for the first time to be a promising indicator of favorable prognosis in breast cancer.

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.

Expression of proteinases and inhibitors in human breast cancer progression and survival

AIMS

The expression of proteinases and their inhibitors determines the extracellular matrix (ECM) turnover in normal and pathological processes. In cancer, proteolysis is abnormally regulated, favouring ECM degradation, which aids tumour invasion and metastasis. Previous studies have determined the expression of proteinases and inhibitors in breast cancer using a variety of techniques, including immunohistochemistry; however, most have looked at the expression of individual proteinases and/or inhibitors. Therefore, the aim of the current study was to determine the simultaneous cellular expression of matrix metalloproteinases (MMPs), plasminogen activators (PAs), and tissue inhibitors of metalloproteinases (TIMPs) in patients with breast cancer and correlate this with clinical pathological staging and survival.

METHODS

Immunohistochemistry was used to determine the expression of proteinases (MMP-1, MMP-2, MMP-3, MMP-9, urokinase-type PA, and tissue-type PA) and inhibitors (TIMP-1 and TIMP-2) in 44 patients with breast cancer.

RESULTS

The expression of all the factors studied was stronger or equivalent in tumour cells than in fibroblasts or inflammatory cells within the tumour section. Both positive and negative trends have emerged in the correlation between the cellular expression of proteinases and inhibitors and breast tumour pathology (tumour grade, lymphovascular invasion, and Nottingham prognostic index).

CONCLUSIONS

The interactions between proteinases and their inhibitors in breast cancer progression are complex. Although there are differences in the expression of these factors that relate to differences in breast cancer pathology, there are no outstanding individual factors that consistently correlate with prognosis. Therefore, different factors are probably important at different stages of the process, and the balance in the relative concentrations of proteinases and inhibitors probably determines ECM degradation in breast tumour invasion and metastasis in vivo.

Immunohistochemical analysis of matrix metalloproteinase-1, -3, and -13 in naturally occurring cartilaginous tumors of dogs

OBJECTIVE

To determine immunoreactivity of matrix metalloproteinase (MMP)-1, -3, and -13 in cartilaginous tumors of dogs, correlate expression of MMP with histologic grade of tumors and clinical outcome of dogs, and compare MMP immunoreactivity between chondrosarcomas and chondromas.

SAMPLE POPULATION

Formalin-fixed, paraffin-embedded tissues obtained from samples of naturally occurring chondrosarcomas (n = 31) and chondromas (8) of dogs that were submitted to our veterinary medical diagnostic laboratory.

PROCEDURE

Histologic sections from each sample were stained with H&E and monoclonal antibody to MMP-1, -3, and -13 by use of an avidin-peroxidase immunohistochemical technique. For each section, histologic grade (I, II, or III) and immunohistochemical expression (0, 1, 2, or 3) were evaluated. Clinical outcome was obtained from medical records or interviews with referring veterinarians and scored as a good outcome, moderate outcome, or poor outcome. Correlations among variables and differences between chondrosarcomas and chondromas were analyzed.

RESULTS

Samples from chondrosarcomas had significantly higher immunoreactivity of MMP-1 and -13, compared with immunoreactivity in samples from chondromas. In chondrosarcomas, a significant positive correlation (r, 0.386) was found between MMP-1 and -13 immunoreactivities, and a significant negative correlation (r, -0.390) was detected between MMP-3 and -13 immunoreactivities.

CONCLUSIONS AND CLINICAL RELEVANCE

A significant increase in expression of collagenases (MMP-1 and -13) in chondrosarcomas, compared with expression in chondromas, suggests that collagenases may play an important role in tumor progression, and possibly metastasis, in chondrosarcomas of dogs.

Differentially expressed genes identified in human melanoma cell lines with different metastatic behaviour using high density oligonucleotide arrays

The increasing incidence of melanoma and the lack of effective treatment, with the exception of tumour excision before the onset of the metastatic phase, make it important to identify genes that may function as new molecular markers for diagnosis and/or prognosis or as new targets for therapy. Recently, a new technique using high density oligonucleotide arrays has been developed to simultaneously screen for the expression of thousands of genes. We used this technique to compare the mRNA expression patterns of two human melanoma cell lines with different metastatic behaviour. Eight differentially expressed genes, namely apolipoprotein CII, tyrosinase-related protein 1, transforming growth factor-beta superfamily, subtilisin-like protein, elongation factor 1 alpha2, alpha2-macroglobulin, human cell division cycle 10 and serine/threonine protein kinase (DYRK1A), were selected to validate the array results by Northern blotting and reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, a reliable correlation between differential expression of these genes in the melanoma cell lines and in fresh lesions of melanocytic tumour progression was demonstrated by RT-PCR analysis. Altogether, our data indicate that high density oligonucleotide arrays are a valuable and reliable tool to screen for differentially expressed genes, and that our study may be considered a basic step in the characterization of genes that are involved in the (malignant) progression of melanoma.

HER2/Neu-mediated activation of the ETS transcription factor ER81 and its target gene MMP-1

In this study, we show that the ETS transcription factor ER81 directly binds to and activates the promoter of the matrix metalloproteinase gene, MMP-1. Further, the oncoprotein HER2/Neu synergizes with ER81 to stimulate MMP-1 transcription. The activation of ER81 by HER2/Neu is mediated by MAP kinases, which phosphorylate ER81 in its N-terminal activation domain. Four respective phosphorylation sites have been identified. Blocking phosphorylation at these sites decreases ER81 transcriptional activity, which can be further diminished by abolishment of phosphorylation at two non-MAP kinase sites. Altogether, our results reveal mechanisms of how phosphorylation of ER81 regulates the expression of target genes such as MMP-1, which may be important for many physiological processes from embryogenesis to adulthood as well as for tumor metastasis.

Urokinase plasminogen activator and plasmin efficiently convert hemofiltrate CC chemokine 1 into its active

We have previously isolated from human hemofiltrate an N-terminally truncated form of the hemofiltrate CC chemokine 1 (HCC-1), and characterized HCC-1[9-74] as a strong agonist of CCR1, CCR5, and to a lower extent CCR3. In this study, we show that conditioned media from human tumor cell lines PC-3 and 143B contain proteolytic activities that convert HCC-1 into the [9-74] form. This activity was fully inhibited by inhibitors of urokinase-type plasminogen activator (uPA), including PA inhibitor-1, an anti-uPA mAb, and amiloride. Pure preparations of uPA processed HCC-1 with high efficiency, without further degrading HCC-1[9-74]. Plasmin could also generate HCC-1[9-74], but degraded the active product as well. The kinetics of HCC-1 cleavage by uPA and plasmin (Michaelis constant, K(m), of 0.76 +/- 0.4 microM for uPA, and 0.096 +/- 0.05 microM for plasmin; catalytic rate constant, k(cat): 3.36 +/- 0.96 s(-1) for uPA and 6 +/- 3.6 s(-1) for plasmin) are fully compatible with a role in vivo. The activation of an abundant inactive precursor into a broad-spectrum chemokine by uPA and plasmin directly links the production of uPA by numerous tumors and their ability to recruit mononuclear leukocytes, without the need for the transcriptional activation of chemokine genes.

Anomalous dystroglycan in carcinoma cell lines

Dystroglycan is a receptor responsible for crucial interactions between extracellular matrix and cytoplasmic space. We provide the first evidence that dystroglycan is truncated. In HC11 normal murine and the 184B5 non-tumorigenic mammary human cell lines, the expected beta-dystroglycan 43 kDa band was found but human breast T47D, BT549, MCF7, colon HT29, HCT116, SW620, prostate DU145 and cervical HeLa cancer cells expressed an anomalous approximately 31 kDa beta-dystroglycan band. alpha-Dystroglycan was udetectable in most of the cell lines in which beta-dystroglycan was found as a approximately 31 kDa species. An anomalous approximately 31 kDa beta-dystroglycan band was also observed in N-methyl-N-nitrosurea-induced primary rat mammary tumours. Reverse transcriptase polymerase chain reaction experiments confirmed the absence of alternative splicing events and/or expression of eventual dystroglycan isoforms. Using protein extraction procedures at low- and high-ionic strength, we demonstrated that both the 43 kDa and approximately 31 kDa beta-dystroglycan bands harbour their transmembrane segment.