Proteolytic degradation of extracellular matrix in tumor invasion

Quercetin Enhances the Suppressive Effects of Doxorubicin on the Migration of MDA-MB-231 Breast Cancer Cell Line

Background: Cancer cell metastasis is facilitated by matrix-metalloproteinases through degradation of extracellular matrix (ECM) proteins and is a major cause of mortality. One of the most common remedies for cancer is chemotherapy, which has many side effects. Therefore, it seems necessary to find a way to reduce the side effects of these drugs while maintaining their anticancer effects. Quercetin (que) is a natural substance that has been reported to have anticancer activities. Objectives: This study aims at evaluating the effect of que in combination with doxorubicin (dox) on the migration of the MDA-MB-231 breast cancer cell line. Methods: The effects of que and dox on cell viability in 24h and 48 h was assessed by MTT assay. Also, the effects of the same drugs on the cancer cells migration were evaluated, using the wound healing assay. Lastly, the effects of que and dox were assessed on the expression of MMP-2 and MMP-9 genes. Results: The combination of 50 µM of que with 32 nM of dox was selected by CI comparison. The viability and migration of cancer cells and the gelatinases genes expression were decreased after treatment with individual drugs. The migration and the expression of MMP-2 and MMP-9 genes after treatment with the combination of que and dox was significantly reduced compared to the treatment with que and dox alone. Conclusions: Que inhibits the viability and migration of MDA-MB-231 cancer cells and synergistically enhances the effects of dox on the survival and migration of these cells. Hence, we propose this drug combination as a path for further research on breast cancer therapy.

A structural mechanism of flavonoids in inhibiting serine proteases

The crystal structure of quercerin:uPA reveals that catechol serves as the functional group in inhibiting serine proteases.

The source of matrix-degrading enzymes in human cancer: Problems of research reproducibility and possible solutions

Matrix degradation is central to tumor pathogenesis. Enzymes that degrade extracellular matrix are abundant in tumors. But which out of the complex mixture of cells that form a tumor produces them? Surprisingly, several hundred studies devoted to this question have provided confusion rather than clarity. Our analysis of these studies identifies likely reasons as to why this may be the case, which has implications for the broader issue of research reproducibility.

Type IV collagen α1-chain noncollagenous domain blocks MMP-2 activation both in-vitro and in-vivo

α1(IV)NC1 inhibits angiogenesis by regulating MAPK activation, this biological function was partly attributed α1(IV)NC1 binding to α1β1-integrin. However, its potent antiangiogenic activity and the molecular targets of α1(IV)NC1 has not been investigated. In the present study, the regulation of MMP-2 activation by α1(IV)NC1 was evaluated. α1β1-integrin which is required for inhibition of angiogenesis is not playing a role in cellular invasion and inhibition of MMP-2 activation by α1(IV)NC1. We found that α1(IV)NC1 binds the CBD of MMP-2 and forming a stable complex that prevents activation of MMP-2. The antiangiogenic activity of α1(IV)NC1 is mediated, in part, by this binding activity. In addition, up-regulation of TIMP-2 by α1(IV)NC1 led to saturation of MT1-MMP binding sites, which in turn led to inhibition of MMP-2 activation. In-vivo studies using α1-integrin null-mice treated with higher doses of α1(IV)NC1 showed integrin independent inhibition of tumor growth and active-MMP-2, without affecting MMP-9, MMP-7 and angiostatin.

Baicalein inhibits the invasion and metastatic capabilities of hepatocellular carcinoma cells via down-regulation of the ERK pathway

Baicalein, a widely used Chinese herbal medicine, has historically been used in anti-inflammatory and anti-cancer therapies. However, the anti-metastatic effect and molecular mechanism(s) of baicalein on hepatocellular carcinoma (HCC) remain poorly understood. Therefore, the purpose of this study was to assess the anti-metastatic effects of baicalein and related mechanism(s) on HCC. Based on assays utilized in both HCC cell lines and in an animal model, we found that baicalein inhibited tumor cell metastasis in vivo and in vitro. Furthermore, after treatment with baicalein for 24 hours, there was a decrease in the levels of matrix metalloproteinase-2 (MMP-2), MMP-9 and urokinase-type plasminogen activator (u-PA) expression as well as proteinase activity in hepatocellular carcinoma MHCC97H cells. Meanwhile, the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 were increased in a dose-dependent fashion. Moreover, baicalein treatment dramatically decreased the levels of the phosphorylated forms of MEK1 and ERK1/2. MEK1 overexpression partially blocked the anti-metastatic effects of baicalein. Combined treatment with an ERK inhibitor (U0126) and baicalein resulted in a synergistic reduction in MMP-2, MMP-9 and u-PA expression and an increase in TIMP-1 and TIMP-2 expression; the invasive capabilities of MHCC97H cells were also inhibited. In conclusion, baicalein inhibits tumor cell invasion and metastasis by reducing cell motility and migration via the suppression of the ERK pathway, suggesting that baicalein is a potential therapeutic agent for HCC.

Protective Effect of Stachybotrys microspora Triprenyl Phenol-7on the Deposition of IgA to the Glomerular Mesangium in Nivalenol-induced IgA Nephropathy Using BALB/c Mice

Activators of tissue proteolysis including Stachybotrys microspora triprenyl phenol (SMTP)-7 are a new class of agents that are expected to be effective for amelioration of chronic tissue destructive diseases. The present study was performed to examine whether SMTP-7 is effective for the amelioration or protection of early-stage IgA nephropathy (IgAN) induced by nivalenol (NIV) in female BALB/c mice. In Experiment 1, mice were administered NIV at 24 ppm in diet for 8 weeks, and during the NIV treatment, they were intraperitoneally injected with SMTP-7 (10 mg/kg) three times a week. In Experiment 2, mice were injected similarly with SMTP-7 during the last 4 weeks of a 16-week NIV treatment. Immunofluorescence analysis revealed an inhibitory effect of SMTP-7 on the glomerular deposition of IgA in Experiment 1; however, it was ineffective in Experiment 2. On the other hand, SMTP-7 did not affect the serum concentration of IgA in both experiments. These results suggest that SMTP-7 has a potential to decrease the progression of IgAN induced by NIV through inhibition of local accumulation of IgA in the glomerular mesangium, while it was ineffective for suppression of IgA production. On the other hand, SMTP-7 was found to be ineffective for already deposited IgA, suggesting that SMTP-7 may not be effective for ameliorating advanced IgAN.

Roles of matrix metalloproteinase-26 in the growth, invasion and angiogenesis of breast cancer

Matrix metalloproteinase-26 (MMP-26) is a novel member of the MMP family and plays a significant role in the progression of estrogen-dependent malignancies. The present study aimed to investigate the roles of MMP-26 in the growth, invasion and angiogenesis of breast cancer. pcDNA3.1(+)-neo expression plasmids carrying the proMMP-26 coding sequence were used to transfect a breast cancer cell line (MCF-7 cells). The mRNA and protein expression of MMP-26 was determined by RT-PCR, immunofluorescence analysis and flow cytometry. The morphology of transfected cells was observed under an electron microscope. An adherence and spreading assay, Boyden chamber assay, in vivo tumorigenicity assay and in vivo angiogenesis were further modeled to elucidate the roles of MMP-26 in the invasion and angiogenesis of breast cancer. Using electron microscopy, the MMP-26-transfected cells demonstrated increased atypia, including unusual mitotic figures, glucogen pools and special lysosomes in the cytoplasm. The adherence and spreading ability of MMP-26-transfected cells were increased significantly compared with cells in the control group. The Boyden chamber assay demonstrated that the migration and invasion ability of MMP-26-transfected cells was dramatically accelerated compared with the control group, but markedly reduced in the presence of anti-MMP-26 antibody. MMP-26 also increased the malignant phenotype in vivo. The number of vessel branches and the total length of vessels induced by MMP-26-transfected cells were significantly increased compared to those induced by non-transfected cells. The plasmid carrying the proMMP-26 gene was successfully transfected into breast cancer cells. Our results demonstrate that MMP-26 overexpression promotes the growth and invasion of breast cancer cells and induces angiogenesis.

Calpains as potential anti-cancer targets

INTRODUCTION

The intracellular signaling cysteine proteases, calpains (specifically the ubiquitous calpains 1 and 2), are involved in numerous physiological and pathological phenomena. Several works have highlighted the implication of calpains in processes crucial for cancer development and progression. For these reasons, calpains are considered by several authors as potential anti-cancer targets.

AREAS COVERED

How calpains are implicated in cancer formation and development, how these enzymes are deregulated in cancer cells and how these proteases could be targeted by anti-cancer drugs. Studies published in the last 10 years are focused on.

EXPERT OPINION

Targeting calpain activity with specific inhibitors could be a novel approach to limiting development of primary tumors and formation of metastases, by inhibiting tumor cell migration and invasion, which allows dissemination as well as tumor neovascularization, which in turn allows expansion. However, such drugs could interfere with anti-cancer treatments, as ubiquitous calpains play crucial roles in chemotherapy-induced apoptosis. For these reasons, drugs targeting calpains would have to be used selectively to avoid interference with other treatments and physiological processes. Further studies will be required concerning the other members of the calpain family and their potential implication in cancer development before considering treatments targeting their activity.

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

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

Alterations in integrin expression modulates invasion of pancreatic cancer cells

BACKGROUND

Factors mediating the invasion of pancreatic cancer cells through the extracellular matrix (ECM) are not fully understood.

METHODS

In this study, sub-populations of the human pancreatic cancer cell line, MiaPaCa-2 were established which displayed differences in invasion, adhesion, anoikis, anchorage-independent growth and integrin expression.

RESULTS

Clone #3 displayed higher invasion with less adhesion, while Clone #8 was less invasive with increased adhesion to ECM proteins compared to MiaPaCa-2. Clone #8 was more sensitive to anoikis than Clone #3 and MiaPaCa-2, and displayed low colony-forming efficiency in an anchorage-independent growth assay. Integrins beta 1, alpha 5 and alpha 6 were over-expressed in Clone #8. Using small interfering RNA (siRNA), integrin beta1 knockdown in Clone #8 cells increased invasion through matrigel and fibronectin, increased motility, decreased adhesion and anoikis. Integrin alpha 5 and alpha 6 knockdown also resulted in increased motility, invasion through matrigel and decreased adhesion.

CONCLUSION

Our results suggest that altered expression of integrins interacting with different extracellular matrixes may play a significant role in suppressing the aggressive invasive phenotype. Analysis of these clonal populations of MiaPaCa-2 provides a model for investigations into the invasive properties of pancreatic carcinoma.

Genome-wide identification of Xenopus matrix metalloproteinases: conservation and unique duplications in amphibians

Background

Matrix metalloproteinases (MMPs) are members of the superfamily of Zn²⁺ dependent extracellular or membrane-bound endopeptidases which have been implicated to play critical roles in vertebrate development and human pathogenesis. A number of MMP genes have been found to be upregulated in some or all organs during frog metamorphosis, suggesting that different MMPs may have different functions in various organs/tissues. The recent advances in EST (expressed sequence tag) sequencing and the completion of the genome of Xenopus (X.) tropicalis prompted us to systematically analyze the existence of MMPs in the Xenopus genome.

Results

We examined X. laevis and X. tropicalis ESTs and genomic sequences for MMPs and obtained likely homologs for 20 out of the 25 MMPs known in higher vertebrates. Four of the five missing MMPs, i.e. MMPs 8, 10, 12 and 27, were all encoded on human Chromosome 11 and the other missing MMP, MMP22 (a chicken MMP), was also absent in human genome. In addition, we identified several novel MMPs which appears to be derived from unique duplications over evolution, are present in the genomes of both Xenopus species.

Conclusion

We identified the homologs of most of the mammalian MMPs in Xenopus and discovered a number of novel MMPs. Our results suggest that MMP genes undergo dynamic changes over evolution. It will be of interest in the future to investigate whether MMP expression and functions during vertebrate development are conserved. The sequence information reported here should facilitate such an endeavor in the near future.

Regulation of COX-2 mediated signaling by alpha3 type IV noncollagenous domain in tumor angiogenesis

Human alpha3 chain, a noncollagenous domain of type IV collagen [alpha3(IV)NC1], inhibits angiogenesis and tumor growth. These biologic functions are partly attributed to the binding of alpha3(IV)NC1 to alphaVbeta3 and alpha3beta1 integrins. alpha3(IV)NC1 binds alphaVbeta3 integrin, leading to translation inhibition by inhibiting focal adhesion kinase/phosphatidylinositol 3-kinase/Akt/mTOR/4E-BP1 pathways. In the present study, we evaluated the role of alpha3beta1 and alphaVbeta3 integrins in tube formation and regulation of cyclooxygenase-2 (COX-2) on alpha3(IV)NC1 stimulation. We found that although both integrins were required for the inhibition of tube formation by alpha3(IV)NC1 in endothelial cells, only alpha3beta1 integrin was sufficient to regulate COX-2 in hypoxic endothelial cells. We show that binding of alpha3(IV)NC1 to alpha3beta1 integrin leads to inhibition of COX-2-mediated pro-angiogenic factors, vascular endothelial growth factor, and basic fibroblast growth factor by regulating IkappaBalpha/NFkappaB axis, and is independent of alphaVbeta3 integrin. Furthermore, beta3 integrin-null endothelial cells, when treated with alpha3(IV)NC1, inhibited hypoxia-mediated COX-2 expression, whereas COX-2 inhibition was not observed in alpha3 integrin-null endothelial cells, indicating that regulation of COX-2 by alpha3(IV)NC1 is mediated by integrin alpha3beta1. Our in vitro and in vivo findings demonstrate that alpha3beta1 integrin is critical for alpha3(IV)NC1-mediated inhibition of COX-2-dependent angiogenic signaling and inhibition of tumor progression.

Matrix metalloproteinase-9 is differentially expressed in nonfunctioning invasive and noninvasive pituitary adenomas and increases invasion in human pituitary adenoma cell line

The complete resection of pituitary adenomas (PAs) is unlikely when there is an extensive local dural invasion and given that the molecular mechanisms remain primarily unknown. DNA microarray analysis was performed to identify differentially expressed genes between nonfunctioning invasive and noninvasive PAs. Gene clustering revealed a robust eightfold increase in matrix metalloproteinase (MMP)-9 expression in surgically resected human invasive PAs and in the (nonfunctioning) HP75 human pituitary tumor-derived cell line treated with phorbol-12-myristate-13-acetate; these results were confirmed by real-time polymerase chain reaction, gelatin zymography, reverse transcriptase-polymerase chain reaction, Western blot, immunohistochemistry, and Northern blot analyses. The activation of protein kinase C (PKC) increased both MMP-9 activity and expression, which were blocked by some PKC inhibitors (Gö6976, bisindolylmaleimide, and Rottlerin), PKC-alpha, and PKC-delta small interfering (si)RNAs but not by hispidin (PKC-beta inhibitor). In a transmembrane invasion assay, phorbol-12-myristate-13-acetate (100 nmol/L) increased the number of invaded HP75 cells, a process that was attenuated by PKC inhibitors, MMP-9 antibody, PKC-alpha siRNA, or PKC-delta siRNA. These results demonstrate that MMP-9 and PKC-alpha or PKC-delta may provide putative therapeutic targets for the control of PA dural invasion.

Perioperative endocrine status and prognosis in early breast cancer

Although the relationship between breast cancer and hormones has been known for almost two centuries, it is only during the last 16 years that evidence suggesting the hormonal profile of the patient at the time of surgery can affect the outcome, came to light. A series of studies investigated the hypothesis that unopposed estrogen (observed during the follicular phase of the cycle) may adversely affect the overall and/or disease-free survival of women operated on at that time. The findings have been, at times, contradictory. The retrospective nature of the studies, poor recording of last menstrual period, small study size, and the possible effect of the timing of the diagnostic procedures (cytology or core biopsy) on the outcome may be responsible for the conflicting results. Despite this, more sophisticated studies based on pathological or hormonal observations/measurements, confirmed the relation of luteal phase surgery to better outcome. Estrogen-induced increased protease activity activates a cascade of proteolysis and allows the more discohesive tumor cells to gain access to the circulation. Moreover, disseminated cells might be able to proliferate easier because of several estrogen-dependent growth factors. Diminished immune function during the follicular phase, because of natural killer cell activity and mononuclear cell phagocytic activity down-regulation may also be implicated in the dissemination of viable tumor cells. Taken together these findings provide a framework for explaining the observation that luteal phase surgery can lead to an improved outcome. By altering the perioperative hormonal milieu it may be possible to reduce deaths from breast cancer in a simple and nontoxic manner.

Evidence for a cooperative role of gelatinase A and membrane type-1 matrix metalloproteinase during Xenopus laevis development

Matrix metalloproteinases (MMPs) are a large family of extracellular or membrane-bound proteases. Their ability to cleave extracellular matrix (ECM) proteins has implicated a role in ECM remodeling to affect cell fate and behavior during development and in pathogenesis. We have shown previously that membrane-type 1 (MT1)-MMP [corrected] is coexpressed temporally and spatially with the MMP gelatinase A (GelA) in all cell types of the intestine and tail where GelA is expressed during Xenopus laevis metamorphosis, suggesting a cooperative role of these MMPs in development. Here, we show that Xenopus GelA and MT1-MMP interact with each other in vivo and that overexpression of MT1-MMP and GelA together in Xenopus embryos leads to the activation of pro-GelA. We further show that both MMPs are expressed during Xenopus embryogenesis, although MT1-MMP gene is expressed earlier than the GelA gene. To investigate whether the embryonic MMPs play a role in development, we have studied whether precocious expression of these MMPs alters development. Our results show that overexpression of both MMPs causes developmental abnormalities and embryonic death by a mechanism that requires the catalytic activity of the MMPs. More importantly, we show that coexpression of wild type MT1-MMP and GelA leads to a cooperative effect on embryonic development and that this cooperative effect is abolished when the catalytic activity of either MMP is eliminated through a point mutation in the catalytic domain. Thus, our studies support a cooperative role of these MMPs in embryonic development, likely through the activation of pro-GelA by MT1-MMP.

Clinical significance of human kallikrein gene 6 messenger RNA expression in colorectal cancer

PURPOSE

Human kallikrein gene 6 (KLK6) is a member of the human kallikrein gene family, and recent studies have found that many kallikreins have altered expression patterns in various malignancies. The purpose of the current study was to quantify the expression of KLK6 in malignant and benign colorectal tissues and to statistically analyze whether KLK6 expression levels correlate with clinicopathologic variables and prognosis in patients with colorectal cancer.

EXPERIMENTAL DESIGNS

Paired colorectal tissue samples from cancerous and corresponding noncancerous tissues were obtained from 63 patients with colorectal cancer who underwent surgical resection. Quantitative analyses of KLK6 mRNA expression were done using real-time quantitative reverse transcription-PCR.

RESULTS

KLK6 mRNA overexpression in cancerous tissues compared with normal counterparts was observed in 57 of 63 (90%) patients. The mean expression level of KLK6 mRNA in cancerous tissues was significantly higher than that in noncancerous tissues (P < 0.0001). Elevated KLK6 expression was significantly correlated with serosal invasion (P < 0.05), liver metastasis (P < 0.05), and advanced Duke's stage (P < 0.01). Furthermore, patients with high KLK6 expression had a significantly poorer actuarial overall survival than patients with low KLK6 expression (5-year overall survival rates: 54% and 73%, respectively, P < 0.05).

CONCLUSIONS

The results of this study indicated that KLK6 mRNA expression was significantly higher in cancerous than in noncancerous colorectal tissues, and high expression of KLK6 mRNA correlated with serosal invasion, liver metastasis, advanced Duke's stage, and a poor prognosis for patients with colorectal cancer.

Expression of stromelysin-1 (MMP-3), gelatinase B (MMP-9), and plasminogen activator system during fetal calvarial development

AIMS

To investigate whether degrading proteases can be found in patent calvarial sutures. Sutural growth and fusion means replacement of the sutural connective tissue, rich in fibronectin and collagen type V, by expanding calvarial bone. Proliferation of one tissue into the border area of another implies the presence of enzymes able to degrade extracellular matrix (ECM). An important family of proteases is the matrix metalloproteinases (MMPs), as is the plasminogen/plasmin system.

METHODS AND RESULTS

Expression of two MMPs with substrate specifity for fibronectin and collagen type V and of the plasminogen activator system was studied by immunohistochemistry in samples of human fetal calvariae (age range weeks 19-35 of gestation). In all cases, intense staining for MMPs, urokinase, and urokinase receptor was found in the sutural connective tissue and along the outer and inner borders of calvarial bone.

CONCLUSIONS

Our findings suggest that degradation of sutural connective tissue takes place during sutural growth. This might facilitate proliferation of calvarial bone. Recently, it was shown that an important regulatory mechanism of sutural growth is apoptosis of osteoblasts in the osteogenic front. Intact fibronectin is known to prevent apoptosis of proliferating osteoblasts while fibronectin degradation induces their apoptosis.

Human kallikrein gene 11 (KLK11) mRNA overexpression is associated with poor prognosis in patients with epithelial ovarian cancer

PURPOSE

The purpose of this study was to examine expression levels of the human tissue kallikrein 11 gene (KLK11) in epithelial ovarian tumors and to identify the relationship between KLK11 expression and patient survival.

EXPERIMENTAL DESIGN

KLK11 mRNA expression was examined by semiquantitative PCR in 64 epithelial ovarian tumors (7 adenomas, 6 low malignant potential tumors, and 51 adenocarcinomas) and in 10 normal ovaries. Semiquantitative PCR results were correlated with clinicopathologic variables and overall survival. cDNA from human normal tissues and tumor tissues was also analyzed.

RESULTS

KLK11 mRNA expression was detected in various human cancer tissues including breast, lung, colon, prostate, pancreas, and ovarian carcinoma. The mean value of relative KLK11 expression ratio was significantly higher in ovarian tumor samples than in normal ovary samples (compared with normal samples: adenoma, P = 0.0006; low malignant potential tumor, P = 0.0049; and carcinoma, P < 0.0001). No statistically significant associations between KLK11 mRNA expression level and clinical stage, histological type, or histological grade were observed. The log-rank test showed that high KLK11 mRNA expression and advanced clinical stage significantly correlated with poor patient survival (P = 0.0185 and P = 0.0043, respectively). High KLK11 mRNA expression and clinical stage remained significantly associated with overall survival (P = 0.0225 and P = 0.0202, respectively) after multivariate analysis.

CONCLUSIONS

KLK11 expression may play an important role in ovarian cancer development and act as an independent prognostic marker in ovarian cancer patients.

An immunohistochemical study of TIMP-3 expression in oesophageal squamous cell carcinoma

Tissue inhibitor of metalloproteinase-3 (TIMP-3) inhibits the activity of matrix metalloproteinase, which may play an important role in carcinoma invasion and metastasis. We have investigated the relationship between TIMP-3 reduction and clinicopathological factors in oesophageal squamous cell carcinoma (ESCC). We examined tissue specimens that had been removed from 90 patients with thoracic oesophageal cancer who had undergone surgery between 1983 and 2001. Immunohistochemical staining was performed by the standard streptavidin–biotin method. Immunostaining of TIMP-3 was seen in the cytoplasm of cancer cells and normal oesophageal epithelial cells, particularly in cells located in shallow areas of the tumour. TIMP-3 preserved (+), moderate (±), and reduced (−) cases accounted for 30, 27, and 33 of the 90 patients, respectively (33, 30, 37%). Significant correlations were observed between TIMP-3 expression and depth of tumour invasion (P=0.001), number of lymph node metastases (P=0.003), infiltrative growth pattern (P=0.003), and disease stage (P=0.005). The survival rates of patients with TIMP-3 (−) cancer were significantly lower than those of patients with TIMP-3 (+) and TIMP-3 (±) cancer (P=0.0003). The mean 5-year survival rates of patients with TIMP-3 (+), (±), and (−) were 50, 58, and 21%, respectively. In conclusion, decreased expression of TIMP-3 protein correlates with invasive activity and metastasis. This makes the prognosis for patients with cancer that has lost TIMP-3 significantly less favourable than that for patients with cancer that has maintained TIMP-3.

Cathepsin D is up-regulated in inflammatory bowel disease macrophages

Down-regulation of receptors involved in the recognition or transmission of inflammatory signals and a reduced responsiveness support the concept that macrophages are 'desensitized' during their differentiation in the intestinal mucosa. During inflammatory bowel disease (IBD) intestinal macrophages (IMACs) change to a reactive or 'aggressive' type. After having established a method of isolation and purification of IMACs, message for cathepsin D was one of the mRNAs we found to be up-regulated in a subtractive hybridization of Crohn's disease (CD) macrophages versus IMACs from control mucosa. The expression of cathepsin D in intestinal mucosa was analysed by immunohistochemistry in biopsies from IBD and control patients and in a mouse model of dextran sulphate sodium (DSS)-induced acute and chronic colitis. IMACs were isolated and purified from normal and inflamed mucosa by immunomagnetic beads armed with a CD33 antibody. RT-PCR was performed for cathepsin D mRNA. Results were confirmed by Northern blot and flow cytometrical analysis. Immunohistochemistry revealed a significant increase in the cathepsin D protein expression in inflamed intestinal mucosa from IBD patients compared to non-inflamed mucosa. No cathepsin D polymerase chain reaction (PCR) product could be obtained with mRNA from CD33-positive IMACs from normal mucosa. Reverse transcription (RT)-PCR showed an induction of mRNA for cathepsin D in purified IMACs from IBD patients. Northern blot and flow cytometry analysis confirmed these results. Cathepsin D protein was also found in intestinal mucosa in acute and chronic DSS-colitis but was absent in normal mucosa. This study shows that expression of cathepsin D is induced in inflammation-associated IMACs. The presence of cathepsin D might contribute to the mucosal damage in IBD.

Heparanase and tumor invasion patterns in human oral squamous cell carcinoma xenografts

The role of heparanase, an endo-beta-glucuronidase specifically degrading heparan sulfate (HS) glycosaminoglycans, in the mechanism of cancer cell invasion was investigated. Three human oral squamous cell carcinoma (SCC) cell lines (i.e., HSC-2, HSC-3 and LMF4), exhibiting various degrees of invasiveness to their surrounding tissues, were xenografted to the tongue of SCID mice in order to establish experimental cancer foci. Cancer cells and their surrounding tissues were examined for the expression of heparanase mRNA by an in situ hybridization technique, and for various basement membrane (BM)-associated molecules (i.e., perlecan, laminins and type IV collagen) by immunohistochemical procedures. BM structures surrounding cancer tissues were also examined by electron microscopy. Increasing levels of heparanase mRNA expression were observed with the progression of cancer invasiveness, as manifested by the destruction of BM structures. Enhanced heparanase enzyme activities in cancer tissues with more invasive properties were demonstrated by the disappearance of HS glycosaminoglycans in the face of retained HS proteoglycan core proteins. These results demonstrated a positive correlation between the heparanase enzyme activities and the invasiveness of human oral SCC. The roles of heparanase in cancer cell invasion were not precisely clarified by the present morphological study, but the enhanced heparanase activity in an early phase of BM destruction by cancer cells suggested the participation of this enzyme from the early phase of cancer invasion.

Human kallikrein gene 13 (KLK13) expression by quantitative RT-PCR: an independent indicator of favourable prognosis in breast cancer

Kallikreins are a group of serine proteases with diverse physiological functions. KLK13 (previously known as KLK-L4) is a novel kallikrein gene located on chromosome 19q13.4 and shares a high degree of homology with other kallikrein family members. Many kallikrein genes were found to be differentially expressed in various malignancies, and their regulation is controlled by steroid hormones in prostate and breast cancer cell lines. We studied the expression of KLK13 by quantitative reverse transcriptase-polymerase chain reaction in 173 patients with epithelial breast carcinoma. An optimal cutoff point equal to the 40th percentile was defined, based on the ability of KLK13 to predict disease-free survival. KLK13 values were then associated with other established prognostic factors and with disease-free survival and overall survival. Higher positivity for KLK13 expression was found in older, oestrogen receptor positive patients. In univariate analysis, KLK13 expression is a significant predictor of improved disease-free survival and overall survival (P<0.001 and P=0.009, respectively). Cox multivariate analysis indicated that KLK13 was an independent prognostic variable in the subgroups of patients with Grade I-II tumours and in patients who were oestrogen receptor and progesterone receptor positive, and node positive. Hazard ratios derived from Cox analysis, related to disease-free survival and overall survival were 0.22 (P=0.001) and 0.24 (P=0.008), respectively, for the Grade I-II group; 0.36 (P=0.008) and 0.44 (P=0.038), respectively, for the node positive group and 0.36 (P=0.008) and 0.18 (P=0.008), respectively, for the oestrogen receptor positive group. The adjusted hazard ratio for progesterone receptor positive patients for disease-free survival was 0.25 (P=0.012). For patients in the node positive and oestrogen receptor positive subgroup (n=51) the adjusted hazard ratio was 0.25 (P=0.006) and for the node positive and progesterone receptor positive subgroup (n=46) the hazard ratio was 0.24 (P=0.008). Taken together, these data suggest that higher KLK13 expression in these subgroups of breast cancer patients is associated with an approximately 55 to 80% reduction in the risk of relapse or death. We conclude that KLK13 expression, as assessed by quantitative reverse transcriptase-polymerase chain reaction, is an independent favourable prognostic marker for breast carcinoma.

Inhibition of endothelial cell functions and of angiogenesis by the metastasis inhibitor NAMI-A

NAMI-A is a ruthenium-based compound with selective anti-metastasis activity in experimental models of solid tumours. We studied whether this activity was dependent on anti-angiogenic ability of NAMI-A. We thus investigated its in vitro effects on endothelial cell functions necessary for angiogenesis to develop, as well as its in vivo effects in the chick embryo chorioallantoic membrane model. Endothelial cell proliferation, chemotaxis, and secretion of the matrix-degrading enzyme metalloproteinase-2 were inhibited by NAMI-A in a dose-dependent manner, and without morphologic signs of cell apoptosis or necrosis. Lastly, NAMI-A displayed a dose-dependent in vivo anti-angiogenic activity in the chorioallantoic membrane model. These data suggest that the anti-angiogenic activity of NAMI-A can contribute to its anti-metastatic efficacy in mice bearing malignant solid tumours.

Correlation between cathepsin D expression and p53 protein nuclear accumulation in oesophageal squamous cell carcinoma

AIM

The lysosomal protease cathepsin D has been reported to be associated with tumour progression in malignant tumours. Expression of the gene encoding cathepsin D is known to be stimulated by oestrogen in mammary cancer cells. Recent experiments revealed that a p53 DNA binding site is located in the promoter region of the cathepsin D gene. This fact indicates that cathepsin D expression may correlate with p53 protein expression. The purpose of this study is to evaluate the expression patterns of the cathepsin D and p53 proteins in oesophageal squamous cell carcinoma (SCC).

METHODS

In 154 patients with oesophageal SCC, expression of the cathepsin D and p53 proteins was measured in tumours by means of immunohistochemistry using monoclonal antibodies against cathepsin D (clone, 1C11) and p53 (clone, BP53-12).

RESULTS

Cathepsin D was detected in tumour cells, although it was not found in normal oesophageal epithelium adjacent to carcinoma. High cathepsin D expression (positive tumour cells > 10%) was detected in 76 of 154 cases (49%) and high p53 nuclear expression (positive tumour cells > 50%) was detected in 70 cases (46%). High cathepsin D expression was significantly associated with invasive tumour growth (p = 0.002), poor prognosis (p = 0.049), and nuclear accumulation of p53 protein (p = 0.001). Overexpression of both p53 and cathepsin D was seen in 45 of the 154 cases (29.2%). In addition, there was a positive correlation between the cathepsin D index (percentage of cathepsin D positive tumour cells) and Ki-67 labelling index (percentage of Ki-67 positive tumour cells) in 154 oesophageal SCCs (rho = 0.257; p = 0.009). However, in multivariate survival analysis, cathepsin D expression by the tumours was not an independent prognostic factor in patients with oesophageal SCC (p = 0.236).

CONCLUSIONS

The expression of cathepsin D by cancer cells may play an important role in the invasive growth of oesophageal SCC. Overexpression of both p53 and cathepsin D was seen frequently in tumours; p53 gene abnormalities may correlate with cathepsin D overexpression in oesophageal SCC.

Immunolocalization of urokinase and its receptor in prematurely fused cranial sutures of infants

In cranial sutural samples derived from five children with premature cranial suture fusion we have performed immunostaining for the urokinase plasminogen activator (uPA) and urokinase receptor (uPAR). We have found a strong reactivity for cell- or matrix-bound uPA and uPAR in the sutural connective tissue and associated with the osteoblasts and osteocytes lining the calvarial bone. The sutural tissue itself showed a banding with different intensity of urokinase and uPAR staining concerning connective tissue. It is proposed that the components of the plasminogen activating system are involved in tissue turnover of sutural tissue and in sutural growth.

The levels of trypsinogen isoenzymes in ovarian tumour cyst fluids are associated with promatrix metalloproteinase-9 but not promatrix metalloproteinase-2 activation

Proteolysis mediated by matrix metalloproteinases (MMPs) and serine proteinases is associated with cancer invasion and metastasis. Activation of latent proMMPs, and especially the proforms of the type IV collagen degrading gelatinases A and B (proMMP-2 and proMMP-9), is thought to be a critical step in this process. We have recently found that human tumour-associated trypsin-2 is a potent activator of proMMP-9 and it also activates proMMP-2 in vitro. Trypsinogen, MMP-2, and MMP-9 are expressed in ovarian cancer. To elucidate the function of trypsin in vivo, we studied whether high concentrations of trypsinogen-1, trypsinogen-2, their alpha(1)-proteinase inhibitor (API) complexes, and tumour-associated trypsin inhibitor (TATI) are associated with proMMP-2 and proMMP-9 activation in ovarian tumour cyst fluids. Zymography and immunofluorometric analysis of 61 cyst fluids showed a significant association between high trypsin concentrations and the activation of MMP-9 (P = 0.003-0.05). In contrast, the trypsin concentrations were inversely associated with the activation of MMP-2 (P = 0.01-0.02). Immunohistochemical analysis of ovarian tumour tissue demonstrated expression of trypsinogen-2 and TATI in the secretory epithelium. MMP-2 was detected both in stromal and epithelial cells whereas MMP-9 was detected in neutrophils and macrophage-like cells in stromal and epithelial areas. These results suggest that trypsin may play a role in the regulation of the MMP-dependent proteolysis associated with invasion and metastasis of ovarian cancer.

Human kallikrein gene 5 (KLK5) expression is an indicator of poor prognosis in ovarian cancer

Kallikrein gene 5 (KLK5, also known as KLK-L2), located on chromosome 19q13.4, is one of the newly identified members of the kallikrein gene family, which is a subgroup of the serine protease enzyme family. In normal human tissues, KLK5 is highly expressed in skin, mammary gland and testis. Preliminary RT-PCR analysis has indicated that KLK5 is expressed in a subset of ovarian tumours. We have thus hypothesized that KLK5 may be a new prognostic indicator in ovarian cancer. We have examined the mRNA expression of KLK5 in 142 malignant ovarian tissues. Tumours were pulverized, total RNA was extracted, and cDNA was prepared by reverse transcription. KLK5 was amplified by PCR using gene specific primers, and the identity of the PCR product was verified by sequencing. Ovarian tissues were then classified as KLK5 positive or negative, based on ethidium bromide staining of the PCR product on agarose gels. KLK5 was found to be highly expressed in 58/142 (41%) of ovarian cancer samples while its level of expression was very low in normal ovarian tissues. We found a strong positive relation between KLK5 expression and tumour grade (P = 0.006) and disease stage (P = 0.027). Univariate survival analysis revealed that patients with ovarian tumours positive for KLK5 expression had an increased risk for relapse and death (P = 0.018 and 0.022, respectively). In multivariate analysis, KLK5 expression showed independent prognostic value only in the subset of tumours with lower grade disease (grades I and II). We conclude that KLK5 expression is associated with more aggressive forms of epithelial ovarian carcinoma and has indepdent prognostic value in low grade tumours.

Expression of tissue inhibitors of metalloproteinases (TIMPs) in hepatocellular carcinoma

BACKGROUND

Matrix metalloproteinases (MMPs) have been implicated in the remodelling of extracellular matrix (ECM), including basement membrane. ECM remodelling is associated with pathological processes, including hepatic fibrosis, tumor invasion and metastasis. Tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 were known to inhibit MMP-9 and MMP-2, respectively. In the present study, we examined the expression of TIMP-1 and TIMP-2 in surgical specimen pairs of hepatocellular carcinoma and nontumoral liver and the correlation between their expression and clinicopathological characteristics.

METHODS

The localization of both transcripts and protein of TIMP-1 and TIMP-2 was studied by using in situ hybridization and immunohistochemistry.

RESULTS

TIMP-1 and TIMP-2 mRNA transcripts were found in tumor cells, hepatocyte, sinusoidal cells, endothelial cells and stromal cells. Signal intensity of TIMP-1 was stronger than that of TIMP-2. The results of immunohistochemical stainings were concordant with those obtained by in situ hybridization. Expression of TIMP-1 and TIMP-2 was observed in tumorous tissue, in nontumorous tissue and in the portions of the tumors adjacent to the capsules. However, a clear difference in TIMP-1 and TIMP-2 mRNA expression was not observed among the three tissue types. The intensity of TIMP-2 expression was generally weaker than that of TIMP-1, and the intensity of TIMP-1 and TIMP-2 mRNA expression did not correlate with variable clinicopathological characteristics.

CONCLUSION

TIMPs was expressed in tumor cells and many cell types of the nontumoral liver. Further investigations for TIMPs' unknown functional role are needed.

Requirement for matrix metalloproteinase stromelysin-3 in cell migration and apoptosis during tissue remodeling in Xenopus laevis

The matrix metalloproteinase (MMP) stromelysin-3 (ST3) was originally discovered as a gene whose expression was associated with human breast cancer carcinomas and with apoptosis during organogenesis and tissue remodeling. It has been shown previously, in our studies as well as those by others, that ST3 mRNA is highly upregulated during apoptotic tissue remodeling during Xenopus laevis metamorphosis. Using a function-blocking antibody against the catalytic domain of Xenopus ST3, we demonstrate here that ST3 protein is specifically expressed in the cells adjacent to the remodeling extracellular matrix (ECM) that lies beneath the apoptotic larval intestinal epithelium in X. laevis in vivo, and during thyroid hormone-induced intestinal remodeling in organ cultures. More importantly, addition of this antibody, but not the preimmune antiserum or unrelated antibodies, to the medium of intestinal organ cultures leads to an inhibition of thyroid hormone-induced ECM remodeling, apoptosis of the larval epithelium, and the invasion of the adult intestinal primodia into the connective tissue, a process critical for adult epithelial morphogenesis. On the other hand, the antibody has little effect on adult epithelial cell proliferation. Furthermore, a known MMP inhibitor can also inhibit epithelial transformation in vitro. These results indicate that ST3 is required for cell fate determination and cell migration during morphogenesis, most likely through ECM remodeling.

Molecular pathogenesis of oral squamous carcinoma

Oral squamous carcinogenesis is a multistep process in which multiple genetic events occur that alter the normal functions of oncogenes and tumour suppressor genes. This can result in increased production of growth factors or numbers of cell surface receptors, enhanced intracellular messenger messenger signalling, and/or increased production of transcription factors. In combination with the loss of tumour suppressor activity, this leads to a cell phenotype capable of increased cell proliferation, with loss of cell cohesion, and the ability to infiltrate local tissue and spread to distant sites. Recent advances in the understanding of the molecular control of these various pathways will allow more accurate diagnosis and assessment of prognosis, and might lead the way for more novel approaches to treatment and prevention.

Induction of matrix metalloprotease-7 is common in mucinous ovarian tumors including early stage disease

Matrix metalloproteases are known to play an important role in tumor invasion by mediating degradation of the extracellular matrix. In this study, we have investigated the immunohistochemical expression of matrix metalloprotease -7 (MMP-7) in 44 mucinous ovarian tumors (9 adenomas, 13 low malignant potential tumors, 22 adenocarcinomas) and 6 normal ovaries. Positive staining of MMP-7 is observed in all mucinous ovarian tumors, whereas little or no staining was observed in surface epithelium as well as the epithelial cells of germinal inclusion cyst of the normal ovary. Positive immunostaining of MMP-7 is also observed in the secreted mucin in the tumor glands, which suggests the secretion of the MMP-7 protein from tumor cells. mRNA expression of MMP-7 was confirmed using RT-PCR. The MMP-7 gene was amplified in parallel with an internal control gene beta-tubulin using a thermal cycler. mRNA expression levels of MMP-7 were significantly elevated in mucinous tumor samples compared with that in normal ovaries. Our results suggest that MMP-7 is frequently overexpressed in mucinous ovarian tumors and secreted with the mucin which is produced from the tumor cells. MMP-7 may therefore contribute to mucinous ovarian tumor development or enhanced growth capacity of mucinous ovarian tumors. MMP-7 may also serve as a target for therapeutic intervention in the down regulation of tumor progression.

Amorphous calcium phosphate-mediated binding of matrix metalloproteinase-9 to fibrin is inhibited by pyrophosphate and bisphosphonate

Coordinate regulation of fibrinolytic and collagenolytic systems is essential for normal tissue remodeling and wound healing. To define the molecular mechanisms which link these two proteolytic systems, we have investigated the role of fibrin in matrix metalloproteinase (MMP) function. Both active and latent forms of MMP-9 (gelatinase B) bind to fibrin in a selective, dose-dependent manner; latent enzyme is activated by plasmin during fibrinolysis. Fibrin binding of MMP-9 is mediated by amorphous calcium phosphate (ACP), and proceeds in a step-wise fashion with formation of ACP as the first and rate-limiting step. MMP-9 rapidly binds preformed ACP to yield a transient ACP: MMP-9 complex that avidly binds fibrin. Here we report the effect(s) on fibrin: ACP: MMP-9 formation/dissociation of pyrophosphate (POP), an endogenous calcification inhibitor, and its bisphosphonate analog, alendronate (PCP). MMP-9 was obtained from neutrophil lysate and ACP formation was monitored turbidimetrically. Free MMP-9, ACP: MMP-9 and fibrin: ACP: MMP-9 complexes were analyzed by gelatin zymography. POP at physiologic concentrations (0.5-2.5 microM) inhibited both ACP formation and subsequent fibrin binding of MMP-9 at orthophosphate concentrations of 250 microM. PCP exhibited a similar inhibitory effect. With both substances, inhibition was slightly overcome (>2.5 microM) by higher phosphate (500 microM). In contrast, supraphysiologic concentrations of either POP or PCP (>50 microM) were required to inhibit MMP-9 binding to preformed ACP or to induce dissociation of preformed ACP: MMP-9 complexes (50-100 microM). Neither POP nor PCP had any effect on preformed fibrin: ACP: MMP-9 at concentrations up 1 mM. POP is an endogenous by-product of numerous metabolic pathways and may regulate bone turnover, soft tissue calcification, and contribute to the pathogenesis of calcium pyrophosphate crystal disease (CPPD). These studies support another role for POP and fibrin: ACP: MMP-9 complexes in physiologic and pathologic processes, including tumorigenesis and cancer metastasis.

Protein markers in colorectal cancer: predictors of liver metastasis

OBJECTIVE

To assess the significance of the expression of five protein markers (nm23, p53, c-erbB-2, u-PA, and VEGF) to the development of metastasis in colorectal cancer.

SUMMARY BACKGROUND DATA

The metastatic cascade is a complex multistep process involving several genetic alterations, angiogenesis activation, and tissue proteolysis. Although the prognosis of colorectal cancer depends on the stage of the tumor, the development of metastasis is difficult to predict.

METHODS

Paraffin-embedded specimens of 58 patients who underwent surgery for colorectal cancer were retrospectively analyzed by immunohistochemistry, and the coexpression of these protein markers was related to patient outcome.

RESULTS

The risk of developing liver secondaries was correlated with the expression of nm23 protein (p < 0.0001); this was also the case in those patients with Dukes' stage B showing positive nm23 immunostaining (p = 0.006). The determination of the number of positive markers or the cumulative intensity score did not improve the predictive value over and above that of nm23 protein alone.

CONCLUSION

Expression of nm23 protein is correlated with the risk of developing liver metastasis. Its evaluation alone may help to determine which patients who have undergone apparently curative resection of a colorectal cancer have an increased risk of liver recurrence, especially those with Dukes' stage B tumors who might be considered for adjuvant chemotherapy.

Matrix metalloproteinase 9 is induced by the Epstein-Barr virus BZLF1 transactivator

Type IV collagenases, matrix metalloproteinase (MMP) 2 and MMP9 are implicated in tumor invasion and metastasis. In patients with nasopharyngeal carcinoma (NPC), poor prognosis due to development of local and distant metastasis has been reported to be predicted by antibody titers against the Z protein which is an AP-1 family transcription factor encoded by the EBV BZLF1 immediate-early gene. Here we report that in patients with NPC, expression of Z in tumor cells correlates with advanced cervical lymph node metastasis which may suggest that Z affects tumor invasion and metastasis. We therefore tested if Z would induce expression of type IV collagenases. Transfection of Z expression plasmid into the C33A epithelial cell line increased expression of MMP9, but MMP2 expression was unaltered. Mutational analysis of the Z protein revealed that, in addition to all three functional domains of Z (dimerization domain, DNA binding domain, and activation domain), the carboxyl terminal 17 amino acids which stabilize the Z protein were necessary for induction of MMP9 expression. Analysis of the MMP9 promoter demonstrated that only AP-1 site close to the transcriptional start-site was essential for transactivation by Z. Previously we reported that Epstein-Barr virus latent membrane protein 1 (LMP1) stimulates MMP9 expression (Yoshizaki et al. Proc. Natl. Acad. Sci. 1998; 95: 3621-6). Thus, Z together with LMP1 may contribute to invasion and metastasis of NPC by inducing expression of MMP9.

Inhibitory role of plasminogen activator inhibitor-1 in invasion and proliferation of HLE hepatocellular carcinoma cells

Plasminogen activator inhibitor (PAI)-1, a serine protease inhibitor, inactivates urokinase-type plasminogen activator (uPA) and regulates degradation of the extracellular matrix; whether it functions for or against tumor progression, however, has been the subject of controversy. To assess the role of PAI-1 in invasion and proliferation of hepatocellular carcinoma (HCC) cells, HLE cells were transfected with a vector capable of expressing an antisense PAI-1 transcript. Analysis of seven stably transfected clones (PAI-1-) showed reductions of 81% in PAI-1 mRNA by northern blot analysis and 63% in the cellular PAI-1 antigen level by enzyme-linked immunosorbent assay (ELISA). There was no change in the levels of secreted PAI-1 or PAI-2. The activity of cellular uPA increased by 54%, without change in the protein level or the secreted uPA activity evaluated by ELISA. Morphologically, PAI-1 antisense induced a spindle shape with narrower cytoplasmic processes in HLE cells. The forced inhibition of PAI-1 increased the invasion and the growth of PAI-1- cells by 75% and 82%, respectively. These results suggest that PAI-1 plays a role in inhibiting invasion and proliferation, and the balance between uPA and PAI-1 expression is important to assess the invasiveness of HCC cells.

PD 098059, an inhibitor of ERK1 activation, attenuates the in vivo invasiveness of head and neck squamous cell carcinoma

Increased mortality of patients with oral cancer largely reflects the local and regional spread of the disease. The invasiveness of these tumours requires hydrolases which are regulated through AP-1-dependent transcriptional mechanisms. Since the amount/activity of transcription factors bound to the AP-1 motif are regulated partly through the extracellular signal-regulated kinases (ERK1/ERK2), we determined the effect of PD 098059, an inhibitor of ERK1/ERK2 activation, on the in vivo invasiveness of a human squamous cell carcinoma cell line (UM-SCC-1) derived from the oral cavity. We utilized the floor of mouth musculature consisting of the mylohyoid, geniohyoid and genioglossus muscle (which are sequentially arranged), as a natural barrier to assess tumour spread in vivo in the nude mouse. Mice were inoculated with tumour cells superficial to the mylohyoid muscle. After 18 days, tumours were injected with either empty liposomes (control) or liposomes containing 5 microM PD 098059 and, after an additional 22 days, the jaws of mice examined histologically. Highly infiltrative tumours, which had penetrated the genioglossus muscle, were evident in 10/12 control mice. In contrast, in 9/12 mice in which the tumours were injected with PD 098059, tumours did not extend beyond the mylohyoid or geniohyoid muscles. Tumours penetrated bone nutrient canals in 7/12 control mice but in only 3/12 PD 098059-treated mice. Neurotropism, characteristic of aggressive oral squamous cell carcinoma, was evident in 6/12 control mice but was completely abolished (0/12 mice) in the PD 098059-treated mice. Using a staging system based on the muscle layer involved, neurotropism, as well as bone involvement, we found the inhibition of invasion to be statistically significant (P < 0.01). The reduced invasiveness of the PD 098059-liposome-treated oral cancers was associated with diminished 92-kDa type IV collagenase and ERK1/ERK2 activities but was not a consequence of a slower tumour growth rate. This is the first study to demonstrate reduced in vivo invasiveness of a malignancy brought about by an inhibitor of ERK1/ERK2 activation. These results raise the exciting possibility that second generation PD 098059 congeners may reduce the spread of the disease in patients afflicted with oral cancers.

Molecular cloning and functional characterization of a snake venom metalloprotease

A cDNA clone, MT-d, encoding metalloprotease precursor was isolated from snake (Agkistrodon halys brevicaudus) venom gland cDNA library. MT-d-I protein containing both metalloprotease and disintegrin domains, and MT-d-II protein containing the metalloprotease domain only were expressed in Escherichia coli and refolded successfully into their functional forms. Each of the refolded enzyme species exhibited distinct substrate specificity. Proteolytic activity of the MT-d-1 was able to hydrolyse type I gelatin, type-III and V collagens in contrast with the catalytic function of MT-d-II. MT-d-I protein having metalloprotease activity was also able to inhibit platelet aggregation. Functionally active MT-d-I protein underwent autoproteolytic processing in vitro to produce metalloprotease and disintegrin; this processing was accompanied by significant changes in the substrate specificity of the enzyme activity. Experimental evidence strongly suggests that the disintegrin domain in the metalloprotease precursor modulates the catalytic function of the enzyme in hydrolysing extracellular matrix proteins.

Effects of sex steroids and growth factors on invasive activity and 5'-deoxy-5-fluorouridine sensitivity in ovarian adenocarcinoma OMC-3 cells

Effects of sex steroids (estradiol-17 beta, E2; progesterone, Prog) and growth factors (epidermal growth factor, EGF; transforming growth factor-alpha, TGF-alpha) on invasive activity and 5'-deoxy-5-fluorouridine (5'-dFUrd) sensitivity of ovarian adenocarcinoma OMC-3 cells were investigated. Tumor cell migration along a gradient of substratum-bound fibronectin and invasion into reconstituted basement membrane were inhibited by 10 microM Prog, but stimulated by 0.1-10 nM EGF and TGF-alpha in a concentration-dependent manner. E2 did not have any effect on tumor cell migration or invasion. The zymography of tumor conditioned medium showed that the treatment of OMC-3 cells with EGF and TGF-alpha resulted in increases of type IV collagenase, stromelysin and urokinase-type plasminogen activator (uPA). EGF and TGF-alpha up-regulated thymidine phosphorylase (dThdPase) expression of tumor cells and consequently enhanced the antiproliferative action of 5'-dFUrd, which is converted to 5-fluorouracil by dThdPase. E2 and Prog did not have significant effects on the expression of proteolytic enzymes and dThdPase, or on the 5'-dFUrd sensitivity of tumor cells. The inhibitory effect of Prog on tumor cell invasion may depend on its inhibitory action on the motility of tumor cells. These results suggest that EGF and TGF-alpha simultaneously up-regulate the potential of ovarian adenocarcinoma cells to invade extracellular matrices and their dThdPase expression, both of which are associated with the specific action of 5'-dFUrd selectively to kill tumor cells with high invasive and metastatic potential.

Binding of matrix metalloproteinase 9 to fibrin is mediated by amorphous calcium-phosphate

In our previous study we demonstrated selective, dose-dependent binding of matrix metalloproteinase-9 (MMP-9), a neutrophil collagenase, to fibrin. Here we investigated the mechanism of this interaction. We found that MMP-9 to fibrin was dependent on formation of a calcium-phosphate intermediate. The intermediate was precipitable by centrifugation and contained a Ca/P ratio of 1.52-1.54, consistent with amorphous calcium-phosphate (ACP). ACP formation exhibited a temperature optimum at 37 degrees C. Gelatin zymography revealed that interaction of ACP with MMP-9 resulted in formation of a high molecular weight ACP:MMP-9 complex which was required for MMP-9 binding to fibrin. Complex formation was dependent on the generation of viable ACP that required both calcium (7.5-10 mM) and phosphate (225-250 microM) (Ca x P product range, 1.7-2.5 mM2). Carbonate (CO3) and sulfate (SO4) were ineffective as calcium counteranions. Preformed ACP rapidly complexed MMP-9. Thus ACP formation was rate-limiting for MMP-9 fibrin binding activity. No MMP-9 fibrin binding activity was noted at 25 degrees C, an observation consistent with lack of ACP production. The significance of these findings is discussed with respect to normal and pathologic wound healing.

In vitro invasion of small-cell lung cancer cell lines correlates with expression of epidermal growth factor receptor

Formation of metastasis is a multistep process involving attachment to the basement membrane, local proteolysis and migration into surrounding tissues, lymph or bloodstream. In the present study, we have analysed the correlation between in vitro invasion and presence of the epidermal growth factor receptor (EGFR) in a panel of 21 small-cell lung cancer (SCLC) cell lines. We have previously reported that ten of these cell lines expressed EGFR protein detected by radioreceptor and affinity labelling assays. In 11 small-cell lung cancer (SCLC) cell lines, EGFR mRNA was detected by Northern blot analysis. In vitro invasion in a Boyden chamber assay was found in all EGFR-positive cell lines, whereas no invasion was detected in the EGFR-negative cell lines. Quantification of the in vitro invasion in 12 selected SCLC cell lines demonstrated that, in the EGFR-positive cell lines, between 5% and 16% of the cells added to the upper chamber were able to traverse the Matrigel membrane. Expression of several matrix metalloproteases (MMP), of tissue inhibitor of MMP (TIMP) and of cathepsin B was evaluated by immunoprecipitation, Western blot analysis and reverse transcriptase polymerase chain reaction (RT-PCR). However, in vitro invasive SCLC cell lines could not be distinguished from non-invasive cell lines based on the expression pattern of these molecules. In six SCLC cell lines, in vitro invasion was also determined in the presence of the EGFR-neutralizing monoclonal antibody mAb528. The addition of this antibody resulted in a significant reduction of the in vitro invasion in three selected EGFR-positive cell lines. Our results show that only EGFR-positive SCLC cell lines had the in vitro invasive phenotype, and it is therefore suggested that the EGFR might play an important role for the invasion potential of SCLC cell lines.

Unique organization and involvement of GAGA factors in transcriptional regulation of the Xenopus stromelysin-3 gene

Expression of the matrix metalloproteinase (MMP) gene stromelysin-3 ( ST3 ) has been shown to be tightly associated with cell migration and apoptosis inmammals and amphibians. This contrasts with most other MMP genes. We demonstrate here that the Xenopus ST3 gene also has a structure distinct from other MMP genes, with its C-terminal half (the hemopexin domain) encoded by 4 instead of 6 exons, as in other MMP genes. Our primer extension analysis reveals the existence of two transcription start sites and at least one is needed for transcription of the promoter in transient transfection assays. Furthermore, our deletion analysis has demonstrated a requirement for at least one GAGA factor binding site for promoter function. In vitro DNA binding and mutational studies have provided strong evidence for the participation of GAGA or GAGA-like factors in transcriptional regulation of the frog ST3 gene. This contrasts with regulation of the human ST3 promoter. These results suggest that the ST3 gene evolved prior to most other metalloproteinase genes and uses distinct regulation pathways to achieve similar expression profiles and serve similar functions in mammals and amphibians.

Binding of latent matrix metalloproteinase 9 to fibrin: activation via a plasmin-dependent pathway

The binding of two matrix metalloproteinases (MMP) to fibrin was evaluated. MMP-2 (72-kDa) and MMP-9 (92-, 130-, and 225-kDa) were selected since both contain a fibronectin-like region and fibronectin binds fibrin. Gelatin zymography indicated selective and dose dependent binding of MMP-9 to fibrin. No MMP-2 binding to fibrin occurred. Densitometry revealed that the 130- and 225-kDa forms demonstrated similar sigmoidal binding profiles whereas 92-kDa uptake was hyperbolic. Fibronectin and TIMP-1 competition studies indicated that the fibronectin and C-terminal MMP-9 domains, respectively, were not involved with fibrin binding. The MMP-9 collagen-like region may be of regulatory significance since type I and II fibrillar and type IV basement membrane collagens demonstrated fibrin binding. During fibrinolysis, latent fibrin-bound MMP-9 was processed to lower molecular weight forms consistent with proteolytic activation. This process was inhibited by epsilon-aminocaproic acid, indicating a plasmin-dependent pathway. The significance of these findings to procoagulant activity and MMP-mediated extracellular matrix destruction during inflammation and tumor invasion and metastasis is discussed.

Expression of matrix metalloproteinases (MMP-1 and -2) and their inhibitors (TIMP-1, -2 and -3) in oral lichen planus, dysplasia, squamous cell carcinoma and lymph node metastasis

Although matrix metalloproteinases (MMPs) are among the potential key mediators of cancer invasion, their involvement in premalignant lesions and conditions is not clarified. Therefore, we studied, using in situ hybridization, immunohistochemistry and zymography the expression and distribution of MMP-1 and -2, and their tissue inhibitors (TIMPs -1, -2 and -3) in oral squamous cell carcinomas (SCC) and lymph node metastases as well as in oral lichen planus, epithelial dysplasias and normal buccal mucosa. In oral SCC and lymph node metastasis, MMP-1 mRNA was detected in fibroblastic cells of tumoral stroma. In two out of ten carcinomas studied, the peripheral cells of neoplastic islands were also positive. MMP-2 mRNA expression was noted in fibroblasts surrounding the carcinoma cells, and no signal in carcinoma cells was detected. A clear TIMP-3 mRNA expression was seen in stromal cells surrounding the neoplastic islands in all SCCs and lymph node metastases studied. TIMP-1 mRNA was detected in some stromal cells surrounding the neoplastic islands, whereas the mRNA expression for TIMP-2 was negligible. On the other hand, expression of MMPs and TIMPs was consistently low in oral epithelial dysplasias, lichen planus and normal mucosa. In certain epithelial dysplasias and lichen planus, MMP-1 and -2 mRNA expressions were detected in few fibroblasts under the basement membrane zone, but normal mucosa was completely negative. In SCC and lymph node metastasis, a detectable immunostaining for MMP-1 in stromal cells and in some carcinoma cells was observed. MMP-2 immunoreactivity was detected in the peripheral cell layer in neoplastic islands and in some fibroblast-like cells of tumoral stroma. Immunostaining for TIMP-3 was detected in stromal cells surrounding the neoplastic islands. A weak positive staining for TIMP-1 was located in tumoral stroma, whereas the immunostaining for TIMP-2 was negative. Using zymography, elevated levels of MMP-2 and MMP-9 were observed in carcinoma samples in comparison with lichen planus or normal oral mucosa. Our results indicate that the studied MMPs and TIMPs are clearly up-regulated during invasion in oral SCC. However, there was also a clear, although weak, up-regulation of the expression of the MMPs but not TIMPs in some of the lichen planus and dysplastic lesions.

Increased matrix metalloproteinase-9 activity in human ovarian cancer cells cultured with conditioned medium from human peritoneal tissue

Ovarian cancer cells disseminate by attachment to the peritoneal mesothelial cell surface of the abdominal cavity. We therefore investigated the influence of conditioned medium (CM) from human peritoneal tissues and mesothelial cells on the secretion of matrix metalloproteinases (MMPs) by ovarian cancer cells. The molecular weights of MMPs stimulating factors derived from human peritoneal tissues and mesothelial cells were estimated using microconcentrators with various cut-off membranes. Human peritoneal tissues were obtained from 12 surgical patients, and mesothelial cells were isolated from three peritoneal specimens. Exposure to CM from peritoneal tissue caused a concentration-dependent increase of the MMP-2 and MMP-9 bands in CM from NOM1 ovarian cancer cells, as shown by zymography. There was a significant difference in the increase of MMP-2 and MMP-9 (2.46-fold and 7.14-fold, respectively, at 0.4 mg/ml protein; P < 0.005). CM from mesothelial cells also significantly increased the secretion of MMP-9 by NOM1 cells. The molecular size of possible MMP-9-stimulating factors secreted by peritoneal tissues and mesothelial cells was above M(r) 100000. Further, CM of peritoneal tissues and mesothelial cells also induced the invasiveness of NOM1 cells. These findings suggest that mesothelial cells may secrete some factors which predominantly induce the MMP-9 production and increase invading cell numbers.

Differential influence of antiestrogens on the in vitro release of gelatinases (type IV collagenases) by invasive and non-invasive breast cancer cells

Matrix metalloproteinases (MMPs) play an important role in tumor cell invasion and cancer metastasis. Accordingly, a higher level of these enzymes has been associated with the invasive phenotype. In the present study the effect of the antiestrogens, Analog II (AII), ICI-182,780 (ICI), and tamoxifen (TAM), on the in vitro release of MMPs, particularly gelatinases A and B by the MDA-MB-231 (MDA) and MCF-7 (MCF) human breast cancer cell lines was investigated using a solid-phase radioassay and substrate gel zymography. Quantitatively, the enzyme activity was found to be higher in the incubation medium from estrogen receptor (ER)-negative and more metastatic MDA cells compared to ER-positive and less metastatic MCF cells. Tissue inhibitor of metalloproteinases-1 (TIMP-1) reduced the enzyme activity in media from both MDA (56.36%) and MCF (71.03%) cells. Differential antiestrogen effects on the two cell lines were observed following 4 days of treatment of cells at a concentration of 10(-6)M. The enzyme activity from MDA cells was not influenced by treatment with any of the antiestrogens, whereas, in MCF cells, ICI produced the greatest enzyme inhibition (47.93%), followed by AII (36.51%) and TAM (24.05%). Concurrent treatment of MCF cells with 17-beta-estradiol (10(-9)M) partially reversed the AII- and TAM-induced but did not alter ICI-induced inhibition of enzyme activity. Substrate gel zymography revealed that among the MMPs, the MDA cells released predominantly progelatinase A (72 kDa) along with minor bands of activated forms, 62 kDa and 59 kDa, whereas progelatinase B (92 kDa) was detected predominantly in the medium from MCF cells. Comparison of the overall antiestrogen effect indicates that ICI is the most potent inhibitor of enzyme activity in ER-positive MCF cells and that antiestrogen treatment may limit the metastatic potential of ER-positive breast cancer.

Presence of cerium-cytochemical reactions of glomerular phosphatases of normal gerbil Meriones crassus: an ultrastructural localization study

Phosphatase cytochemical activity in the normal glomerulus of the desert gerbil Meriones crassus was demonstrated using cerium ions as capturing agents. Three major enzymes have been recognized: sodium-potassium adenosine triphosphatase (Na(+)-K(+)-ATPase), alkaline phosphatase (ALPase) and acid phosphatase (ACPase). However, cytochemical staining for these markers to map their localizations and distributions reveal a high positivity of Na(+)-K(+)-ATPase. This appeared as uniform dense precipitates surrounding the glomerular basement membrane (GBM) and the plasma membranes of the epithelial and endothelial cells of the glomerular layers. Negligible ALKase reaction product being over the glomerular epithelia including the GBM. In contrast, the cytochemical profiles of ACPase was unusual, with dense reaction products extensively covering the endoplasmic reticulum at the region of Golgi apparatus products lysosomes (GERL) complex, including its cisternal and tubular elements and the lysosomal-vacuolar apparatus of the glomerular epithelial cells. All other subcellular organelles showed no activity. For Na(+)-K(+)-ATPase, the reaction product was successive when acetate buffer (as decalcifying agent, pH 5.0) was used. This reaction was still seen when a medium containing levamisole was used. Cytochemical controls for all enzymes were incubated in substrate-free media including those using levamisole as an inhibitor of ALPase. The data presented, which is reported for the first time, is not an attempt to determine the contribution of the selected phosphatases in the glomerular physiology and pathology. Such findings may, nevertheless, have functional implications in the fact that these markers may be involved in the ultrafiltration and other metabolic activities of the glomerulus at the molecular and/or cellular level. In addition to earlier morphological and recent histochemical work, the present study updates and recognizes information to be used as a baseline to which the gerbil model can now be employed to investigate the behavioural adaptations of the desert rodents.

An in vitro invasion model for human renal cell carcinoma cell lines mimicking their metastatic abilities

We developed a modified in vitro invasion assay system using monolayers of vascular endothelial cells. A type I collagen gel was formed in plastic dishes, and overlaid with type IV collagen. Calf pulmonary arterial endothelial (CPAE) cells were seeded onto these plates, and incubated until they reached confluence. Five human renal cell carcinoma cell lines with various metastatic potentials in vivo were then seeded on the monolayer CPAE cells, and their colony formation and invasion activities were examined for 9 days. At day 4, the highly metastatic cell lines increased the number of colony foci on monolayer CPAE cells several fold higher than their poorly metastatic counterpart. The horizontal spreading patterns were also different between poorly and highly metastatic cell lines. On day 9, the number of carcinoma foci that penetrated the monolayer of CPAE cells and type IV collagen sheets into type I collagen gels in highly metastatic cell lines greatly increased as compared with that of poorly metastatic cell lines. Our in vitro invasion assay using monolayer CPAE cells would be useful to evaluate protease activities and colony formation during invasion.

The proteolytic potential of normal human melanocytes: comparison with other skin cells and melanoma cell lines

To understand the contribution of epidermal melanocytes in the proteolytic potential of human skin, we have studied melanocytes grown in a low-serum medium deprived of phorbol esters, cholera toxin, and other non-physiological supplements. We focused on the plasminogen activation system and certain matrix metalloproteinases (gelatinases). Supposing that the proteolytic activity of cells can influence binding to collagen matrix and its reorganization, we have analyzed these parameters as well. We found that human melanocytes secreted tissue-type plasminogen activator and utilised it to generate cell-bound plasmin. No urokinase-type plasminogen activator was detected in the cultures but its receptor was found in cell extracts. Both the 72 kDa and 92 kDa gelatinases were secreted by the cells and in equal amounts. In addition, melanocytes secreted the wide-spectrum proteinase inhibitor alpha-2-macroglobulin. Melanocytes cast into collagen matrices retained a rounded morphology, did not extend processes, and were unable to contract collagen lattices. As a control, these parameters were investigated in parallel in cultures of human keratinocytes, dermal fibroblasts, and two melanoma cell lines. The obtained characteristics suggest that normal human melanocytes are proteolytically active cells. This function may pertain to skin physiology and pathophysiology.