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

Exosome-Mediated Activation of the Prostasin-Matriptase Serine Protease Cascade in B Lymphoma Cells

Prostasin and matriptase are extracellular membrane serine proteases with opposing effects in solid epithelial tumors. Matriptase is an oncoprotein that promotes tumor initiation and progression, and prostasin is a tumor suppressor that reduces tumor invasion and metastasis. Previous studies have shown that a subgroup of Burkitt lymphoma have high levels of ectopic matriptase expression but no prostasin. Reducing the matriptase level via small interfering RNAs in B lymphoma cells impeded tumor xenograft growth in mice. Here, we report a novel approach to matriptase regulation in B cancer cells by prostasin via exosomes to initiate a prostasin-matriptase protease activation cascade. The activation and shedding of matriptase were monitored by measuring its quantity and trypsin-like serine protease activity in conditioned media. Sustained activation of the protease cascade in the cells was achieved by the stable expression of prostasin. The B cancer cells with prostasin expression presented phenotypes consistent with its tumor suppressor role, such as reduced growth and increased apoptosis. Prostasin exosomes could be developed as an agent to initiate the prostasin-matriptase cascade for treating B lymphoma with further studies in animal models.

The Proteolytic Landscape of Ovarian Cancer: Applications in Nanomedicine

Ovarian cancer (OvCa) is one of the leading causes of mortality globally with an overall 5-year survival of 47%. The predominant subtype of OvCa is epithelial carcinoma, which can be highly aggressive. This review launches with a summary of the clinical features of OvCa, including staging and current techniques for diagnosis and therapy. Further, the important role of proteases in OvCa progression and dissemination is described. Proteases contribute to tumor angiogenesis, remodeling of extracellular matrix, migration and invasion, major processes in OvCa pathology. Multiple proteases, such as metalloproteinases, trypsin, cathepsin and others, are overexpressed in the tumor tissue. Presence of these catabolic enzymes in OvCa tissue can be exploited for improving early diagnosis and therapeutic options in advanced cases. Nanomedicine, being on the interface of molecular and cellular scales, can be designed to be activated by proteases in the OvCa microenvironment. Various types of protease-enabled nanomedicines are described and the studies that focus on their diagnostic, therapeutic and theranostic potential are reviewed.

Comparative study of the binding between chlorogenic acid and four proteins by isothermal titration calorimetry, spectroscopy and docking methods

As a polyphenolic compound, chlorogenic acid has antioxidant, anti-inflammatory, antiviral, anti-obesity and other effects. Based on the interactions between chlorogenic acid and the proteins (human serum albumin (HSA), pepsin (Pep), trypsin (Try), fat mass and obesity-associated protein (FTO)), results will provide clues for screening effective inhibitors. The interaction between chlorogenic acid and the four proteins (HSA, Pep, Try, FTO) was analyzed by the aid of fluorescence quenching, synchronous fluorescence, three-dimensional fluorescence, isothermal titration calorimetry, and molecular docking. It can be concluded that there is no obvious interaction between chlorogenic acid and FTO. The binding affinity between chlorogenic acid and three proteins is HSA > Try > Pep. The binding process is spontaneous, and the quenching type is static quenching. Hydrophobic interaction and hydrogen bonding is observed in the binding process. This study provides valuable information for understanding the interaction mechanism between chlorogenic acid and proteins, and provides clues for screening inhibitors.

Active MMP-8 point-of-care (PoC)/chairside enzyme-test as an adjunctive tool for early and real-time diagnosis of peri-implantitis

Objective

The aim of this study was to investigate the utility of the active matrix metalloproteinase (aMMP‐8)‐point‐of‐care (PoC) test as a quantitative real‐time chair‐side diagnostic tool for peri‐implant diagnosis, as well as assess the potentially developing and ongoing risk relative to the traditional clinical methods.

Background

Current peri‐implant and periodontal disease diagnoses rely on clinical and radiological examinations. This case‐control study investigated the applicability of aMMP‐8‐PoC immunotest for quantitative real‐time diagnosis and monitoring of dental implants in health and disease.

Methods

Sixty‐eight patients visiting a specialist clinic for maintenance following dental implant placement underwent assessment of their peri‐implant health. aMMP‐8‐PoC peri‐implant sulcular fluid (PISF) lateral‐flow immunotests were performed using ImplantSafe® technology quantitated by ORALyzer®. In addition, the PISF samples were analyzed for total MMP‐8, calprotectin, and interleukin (IL)‐6 by enzyme‐linked immunosorbent assays (ELISA), aMMP‐8 by western immunoblot, and MMP‐2 and MMP‐9 by gelatin zymography.

Results

The aMMP‐8‐PoC test promptly recorded and reflected peri‐implant disease, differentiating it clearly from health. X‐ray findings (bone loss > 2 mm), peri‐implant pocket depth ≥ 3 mm, and bleeding on probing were significantly more prevalent among implants positive for the aMMP‐8‐PoC test. aMMP‐8/ORALyzer analysis was more precise in recording disease than total MMP‐8, calprotectin, IL‐6, MMP‐2, and MMP‐9.

Conclusions

The aMMP‐8‐PoC test can be conveniently implemented to alert for and detect active collagenolysis affecting peri‐implant tissues, both in the early and advanced stages of the disease. Active and fragmented MMP‐8 exhibits a strong and significant association with peri‐implantitis as compared to total MMP‐8 and other biomarkers and can be utilized as the POC/chairside biomarker of choice in the new classification of peri‐implantitis.

Magnetic CuFe2O4 with intrinsic protease-like activity inhibited cancer cell proliferation and migration through mediating intracellular proteins

Protease has been widely used in biological and industrial fields. Developing efficient artificial enzyme mimics remains a major technical challenge due to the high stability of peptide bonds. Nanoenzymes with high stability, high activity and low cost, provided new opportunities to break through natural enzyme inherent limitations. However, compared with many nanomaterials with inherent peroxidase activity, the intrinsic mimic proteases properties of magnetic nanomaterials were seldom explored, let alone the interaction between magnetic nanomaterials and cellular proteins. Herein, we reported for the first time that magnetic CuFe₂O₄ possesses inherent protease activity to hydrolyze bovine serum albumin (BSA) and casein under physiological conditions, and the CuFe₂O₄ is more resistant to high temperature than the natural trypsin. It also exhibited significantly higher catalytic efficiency than other copper nanomaterials and can be recycled for many times. Protease participated in pathophysiological processes and all stages of tumor progression. Interesting, CuFe₂O₄ exhibited anti-proliferative effect on A549, SKOV3, HT-29, BABL-3T3 and HUVEC cells, as well as it was particularly sensitive against SKOV3 cells. CuFe₂O₄ was about 30 times more effective than conventional chemotherapy drugs oxaliplatin and artesunate against SKOV3 cells. In addition, CuFe₂O₄ also mediated the expression of intracellular proteins, such as MMP-2, MMP-9, F-actin, and NF-kB, which may be associated with global protein hydrolysis by CuFe₂O₄, leading to inhibition of cell migration. The merits of the high magnetic properties, good protease-mimic and antitumor activities make CuFe₂O₄ nanoparticles very prospective candidates for many applications such as proteomics and biotechnology.

An aMMP-8 Point-of-Care and Questionnaire Based Real-Time Diagnostic Toolkit for Medical Practitioners

The aim of this cross-sectional study is to propose an efficient strategy based on biomarkers adjunct with an interview/questionnaire covering risk factors for periodontitis for the identification of undiagnosed periodontitis by medical professionals. Active matrix metalloproteinase (aMMP)-8 levels in mouthrinse were analyzed by a point-of-care (PoC)/chairside lateral-flow immunotest, and salivary total MMP-8, total MMP-9 and calprotectin levels were analyzed by enzyme-linked immunosorbent assays (ELISAs) and active MMP-9 by gelatin zymography for 149 Greek patients. Patients underwent a full-mouth oral health examination for diagnosis according to the 2018 classification system of periodontal diseases. In addition, patient characteristics (risk factors: age, gender, education level, smoking and body mass index) were recorded. Receiver operating curve (ROC) analysis indicated better diagnostic precision to identify undiagnosed periodontitis for oral fluid biomarkers in adjunct with an interview/questionnaire compared with a plain questionnaire (i.e., risk factors): aMMP-8 AUC (95% confidence interval) = 0.834 (0.761-0.906), total MMP-8 = 0.800 (0.722-0.878), active MMP-9 = 0.787 (0.704-0.870), total MMP-9 = 0.773 (0.687-0.858) and calprotectin = 0.773 (0.687-0.858) vs. questionnaire = 0.764 (0.676-0.851). The findings of this study suggest that oral fluid biomarker analysis, such as a rapid aMMP-8 PoC immunotest, could be used as an adjunct to an interview/questionnaire to improve the precision of timely identification of asymptomatic, undiagnosed periodontitis patients by medical professionals. This strategy appears to be viable for referring patients to a dentist for diagnosis and treatment need assessment.

EnDuo, a novel derivative of Endostar, inhibits the migration of colon cancer cells, suppresses matrix metalloproteinase-2/9 expression and impedes AKT/ERK activation

BACKGROUND/AIMS

Colon cancer remains a life-threating disease with increasing morbidity and mortality worldwide despite the advancement in modern medical treatment. Therefore, novel and effective anti-colon cancers drugs are urgently needed. In this study, we investigated the anti-metastatic property EnDuo, a modified version of Endostar, and the underlying mechanisms.

METHODS

Colon cancer cells were treated with different concentrations of EnDuo (50 μg/mL, 100 μg/mL, 200 μg/mL), and Endostar (100 μg/mL) as positive control. Cell Counting Kit-8 assay was performed to test the effect of EnDuo on cell viability. A scratch wound assay and transwell assay were employed to evaluate the relocation and motility of malignant colon cells following treatment with EnDuo. Western blot analysis was used to determine inhibitory effects of EnDuo by detecting the phosphorylation level of AKT and ERK proteins, and the expression of MMP-2 and MMP-9 proteins.

RESULTS

Our results showed that EnDuo impedes the migration of colon cancer cells in a dose-dependent manner. At the molecular level, EnDuo induced a significant reduction in the phosphorylation of AKT and ERK proteins, and inhibited the expression of MMP-2 and MMP-9 proteins.

CONCLUSIONS

Collectively, these results demonstrate that EnDuo exhibits a comparable anti-metastatic effect by suppressing the migration of colon cancer cells. Possibly, EnDuo interrupts the PI3K/AKT/ERK signaling pathway to arrest cell migration. Our study provides a novel insight to the potential clinical applications of EnDuo against colon cancers in the future.

Role of trypsin and protease-activated receptor-2 in ovarian cancer

Proteases have been implicated in the tumorigenesis and aggressiveness of a variety of cancer types. In fact, proteases have proven to be very clinically useful as tumor biomarkers in the blood of patients. Proteases are typically involved in complex systems of substrates, activators, and inhibitors, thus making our ability to establish their exact function in cancer more difficult. Trypsin, perhaps the most famous of proteases, has been shown to play a role in cancer progression, but its functional role in ovarian cancer has not been much studied. PAR2, a transmembrane receptor that is known to be activated by trypsin, has been reported to be associated with ovarian cancer. Here, we found that stimulation of ovarian cancer cell lines with trypsin or PAR2 activating peptide markedly increased MAPK signaling and cell proliferation. Additionally, HE4, a WAP-family glycoprotein and ovarian cancer biomarker, was found to inhibit trypsin degradation, thereby retaining its activity. Patient data seemed to support this phenomenon, as the serum of ovarian cancer patients with high HE4 expression, revealed significantly elevated trypsin levels. These data support the hypothesis that trypsin plays a tumorigenic role in ovarian cancer, which can be mediated by its receptor PAR2, and potentiated by HE4.

The Antiviral Potential of Host Protease Inhibitors

The replication of numerous pathogenic viruses depends on host proteases, which therefore emerged as potential antiviral drug targets. In some cases, e.g., for influenza viruses, their function during the viral propagation cycle is relatively well understood, where they cleave and activate viral surface glycoproteins. For other viruses, e.g., Ebola virus, the function of host proteases during replication is still not clear. Host proteases may also contribute to the pathogenicity of virus infection by activating proinflammatory cytokines. For some coronaviruses, human proteases can also serve in a nonproteolytical fashion simply as receptors for virus entry. However, blocking of such protein-protein contacts is challenging, because receptor surfaces are often flat and difficult to address with small molecules. In contrast, many proteases possess well-defined binding pockets. Therefore, they can be considered as well-druggable targets, especially, if they are extracellularly active. The number of their experimental crystal structures is steadily increasing, which is an important prerequisite for a rational structure-based inhibitor design using computational chemistry tools in combination with classical medicinal chemistry approaches. Moreover, host proteases can be considered as stable targets, and their inhibition should prevent rapid resistance developments, which is often observed when addressing viral proteins. Otherwise, the inhibition of host proteases can also affect normal physiological processes leading to a higher probability of side effects and a narrow therapeutic window. Therefore, they should be preferably used in combination therapies with additional antiviral drugs. This strategy should provide a stronger antiviral efficacy, allow to use lower drug doses, and minimize side effects. Despite numerous experimental findings on their antiviral activity, no small-molecule inhibitors of host proteases have been approved for the treatment of virus infections, so far.

MAPK inhibitors induce serine peptidase inhibitor Kazal type 1 (SPINK1) secretion in BRAF V600E-mutant colorectal adenocarcinoma

The mitogen-activated protein kinase (MAPK) pathway plays a central role in colorectal cancers (CRC). In particular, BRAF V600E-mutant tumors, which represent around 10% of CRCs, are refractory to current therapies. Overexpression and secretion of serine peptidase inhibitor Kazal type 1 (SPINK1) are observed in around 50% of CRCs, and its serum level can be used as a biomarker for poor prognosis. Utilizing a recently developed extendable blocking probe assay, we analyzed the BRAF mutation status in a CRC patient cohort (N = 571) using tissue-derived RNA as the starting material. From the same RNA samples, we measured the relative SPINK1 expression levels using a quantitative real-time PCR method. Expression of mutant BRAF V600E correlated with poor prognosis, as did low expression of SPINK1 mRNA. Further, BRAF V600E correlated negatively with SPINK1 levels. In order to investigate the effect of MAPK pathway-targeted therapies on SPINK1 secretion, we conducted in vitro studies using both wild-type and V600E CRC cell lines. BRAF inhibitor vemurafenib, and subsequent MAPK pathway inhibitors trametinib and SCH772984, significantly increased SPINK1 secretion in V600E CRC cell lines Colo205 and HT-29 with a concomitant decrease in trypsin-1 and -2 secretion. Notably, no SPINK1 increase or trypsin-1 decrease was observed in BRAF wild-type CRC cell line Caco-2 in response to MAPK pathway inhibitors. In further mechanistic studies, we observed that only trametinib was able to diminish completely both MEK and ERK phosphorylation in the V600E CRC cells. Furthermore, the key regulator of integrated stress response, activating transcription factor 4 (ATF-4), was downregulated both at mRNA and at protein level in response to trametinib treatment. In conclusion, these data suggest that sustained inhibition of not only MAPK pathway activation, but also ATF-4 and trypsin, might be beneficial in the therapy of BRAF V600E-mutant CRC and that SPINK1 levels may serve as an indicator of therapy response.

Biomarker development, from bench to bedside

This review describes studies performed by our group and other laboratories in the field aimed at development of biomarkers not only for cancer but also for other diseases. The markers covered include tumor-associated trypsin inhibitor (TATI), tumor-associated trypsin (TAT), human chorionic gonadotropin (hCG), prostate-specific antigen (PSA) and their various molecular forms, their biology and diagnostic use. The discovery of TATI was the result of a hypothesis-driven project aimed at finding new biomarkers for ovarian cancer among urinary peptides. TATI has since proved to be a useful prognostic marker for several cancers. Recently, it has been named Serine Peptidase Inhibitor Kazal Type 1 (SPINK1) after being rediscovered by several groups as a tumor-associated peptide by gene expression profiling and proteomic techniques and shown to promote tumor development by stimulating the EGF receptor. To explain why a trypsin inhibitor is strongly expressed in some cancers, research focused on the protease that it inhibited led to the finding of tumor-associated trypsin (TAT). Elevated serum concentrations of TAT-2 were found in some cancer types, but fairly high background levels of pancreatic trypsinogen-2 limited the use of TAT-2 for cancer diagnostics. However, trypsinogen-2 and its complex with α1-protease inhibitor proved to be very sensitive and specific markers for pancreatitis. Studies on hCG were initiated by the need to develop more rapid and sensitive pregnancy tests. These studies showed that serum from men and non-pregnant women contains measurable concentrations of hCG derived from the pituitary. Subsequent development of assays for the subunits of hCG showed that the β subunit of hCG (hCGβ) is expressed at low concentrations by most cancers and that it is a strong prognostic marker. These studies led to the formation of a working group for standardization of hCG determinations and the development of new reference reagents for several molecular forms of hCG. The preparation of intact hCG has been adopted as the fifth international standard by WHO. Availability of several well-defined forms of hCG made it possible to characterize the epitopes of nearly 100 monoclonal antibodies. This will facilitate design of immunoassays with pre-defined specificity. Finally, the discovery of different forms of immunoreactive PSA in serum from a prostate cancer patient led to identification of the complex between PSA and α1-antichymotrypsin, and the use of assays for free and total PSA in serum for improved diagnosis of prostate cancer. Epitope mapping of PSA antibodies and establishment of PSA standards has facilitated establishment well-standardized assays for the various forms of PSA.

Do salivary and serum collagenases have a role in an association between obstructive sleep apnea syndrome and periodontal disease? A preliminary case-control study

OBJECTIVES

Despite increasing evidence for an association of obstructive sleep apnea syndrome (OSAS) and periodontal disease, the pathophysiological linking mechanisms remain unclear. This study aims to evaluate the salivary and serum matrix metalloproteinase-2, -8, -9 (MMP-2, -8, -9), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), myeloperoxidase (MPO), neutrophil elastase (NE), neutrophil gelatinase-associated lipocalin (NGAL), as well as degree of activation of MMP-2, -9 of patients with and without OSAS.

DESIGN

A total of 50 individuals were included in the study. There were 13, 17 and 20 individuals, respectively in the control (non-OSAS) group, mild-to-moderate OSAS and severe OSAS groups. Saliva, serum samples and clinical periodontal parameters were collected. Biofluid samples were analysed by immunofluorometric assay (IFMA), enzyme-linked immunosorbent assay (ELISA), western immunoblotting and gelatine zymography. Statistical analyses were performed using D'Agostino-Pearson omnibus normality test, Kruskal-Wallis test and Spearman rho rank correlation analysis.

RESULTS

There were no statistically significant differences in clinical periodontal parameters between the study groups. Salivary NE and proMMP-2 levels were significantly lower in the OSAS groups than the control group (p<0.05). Serum proMMP-9 concentration and the degree of MMP-9 activation in saliva were significantly lower in the severe OSAS group than the control group (p<0.05). There were significant correlations between salivary and serum proMMP-9 and -2 concentrations (p<0.05). Serum proMMP-2, NE and salivary proMMP-9 and -2 negatively correlated with indicators of OSAS severity (p<0.05).

CONCLUSIONS

The present findings do not support a pathophysiological link between the severity of OSAS and clinical periodontal status via neutrophil enzymes or MMPs.

Molecular functions of the iron-regulated metastasis suppressor, NDRG1, and its potential as a molecular target for cancer therapy

N-myc down-regulated gene 1 (NDRG1) is a known metastasis suppressor in multiple cancers, being also involved in embryogenesis and development, cell growth and differentiation, lipid biosynthesis and myelination, stress responses and immunity. In addition to its primary role as a metastasis suppressor, NDRG1 can also influence other stages of carcinogenesis, namely angiogenesis and primary tumour growth. NDRG1 is regulated by multiple effectors in normal and neoplastic cells, including N-myc, histone acetylation, hypoxia, cellular iron levels and intracellular calcium. Further, studies have found that NDRG1 is up-regulated in neoplastic cells after treatment with novel iron chelators, which are a promising therapy for effective cancer management. Although the pathways by which NDRG1 exerts its functions in cancers have been documented, the relationship between the molecular structure of this protein and its functions remains unclear. In fact, recent studies suggest that, in certain cancers, NDRG1 is post-translationally modified, possibly by the activity of endogenous trypsins, leading to a subsequent alteration in its metastasis suppressor activity. This review describes the role of this important metastasis suppressor and discusses interesting unresolved issues regarding this protein.

A novel discriminant score based on tumor-associated trypsin inhibitor for accurate diagnosis of metastasis in patients with breast cancer

Invasion and metastasis of solid tumors require proteolytic enzymes for degradation of the basal membrane and extracellular matrix. Currently, there are no reliable methodologies to predict the risk for metastatic disease. In this context, our aim has been focused on the development of a noninvasive score based on tumor-associated trypsin inhibitor (TATI) for the assessment of metastasis in patients with breast cancer. TATI, trypsin, and soluble epidermal growth factor receptor (sEGFR) were assayed by enzyme-linked immunosorbent assay. CA 15.3 serum level was assayed by microparticle enzyme immunoassay in 265 patients with breast cancer. Statistical analyses were performed by logistic regression and receiver operating characteristic analysis curves. Using multivariate discriminant analysis, a score is selected based on absolute values of the four biochemical markers: TATI-metastatic breast cancer score (TATI-MBCS) = [0.03 × CA 15.3 (U/L) + 0.039 × TATI (ng/ml) + 0.04 × trypsin (ng/ml) + 0.023 × sEGFR (ng/ml) - 6.49 (numerical constant)]. This function correctly classified 84% of metastatic breast cancer at cutoff value = 0.62 (i.e., greater than 0.62 indicates patients with metastatic breast cancer and less than 0.62 indicates patients with nonmetastatic breast cancer). In conclusion, TATI-MBCS is a novel, noninvasive, and simple score which can be applied to discriminate patients with metastatic breast cancer.

Proteolytic cleavage and truncation of NDRG1 in human prostate cancer cells, but not normal prostate epithelial cells

NDRG1 (N-myc downstream regulated gene-1) is a metastasis suppressor that is down-regulated in prostate cancer. NDRG1 phosphorylation is associated with inhibition of metastasis and Western blots indicate two bands at ~41 and ~46 kDa. Previous investigations by others suggest the higher band is due to NDRG1 phosphorylation. However, the current study using a dephosphorylation assay and the Phos-tag (phosphate-binding tag) SDS/PAGE assay, demonstrated that the 46 kDa NDRG1 protein band was not due to phosphorylation. Further experiments showed that the NDRG1 protein bands were not affected upon glycosidase treatment, despite marked effects of these enzymes on the glycosylated protein, fetuin. Analysis using RT–PCR (reverse transcriptase–PCR) demonstrated only a single amplicon, and thus, the two bands could not result from an alternatively spliced NDRG1 transcript. Western-blot analysis of prostate cancer cell lysates identified the 41 kDa band to be a truncated form of NDRG1, with MS confirming the full and truncated proteins to be NDRG1. Significantly, this truncated protein was not present in normal human PrECs (prostate epithelial cells). Western-blot analysis using anti-NDRG1 raised to its N-terminal sequence failed to detect the truncated protein, suggesting that it lacked N-terminus amino acids (residues 1–49). Sequence analysis predicted a pseudotrypsin protease cleavage site between Cys⁴⁹–Gly⁵⁰. Such cleavage of NDRG1 in cancer cells may result in loss of NDRG1 tumour suppressive activity.

Low trypsinogen-1 expression in pediatric ulcerative colitis patients who undergo surgery

AIM: To investigate whether matrix metalloproteinases-9 (MMP-9) or trypsinogens could serve as histological markers for an aggressive disease course in pediatric ulcerative colitis (UC).

METHODS: We identified 24 patients with pediatric onset (≤ 16 years) UC who had undergone surgery during childhood/adolescence a median of 2.1 years (range 0.1-7.4 years) after the diagnosis (between 1990 and 2008) in Children’s Hospital, Helsinki, Finland. We also identified 27 conservatively treated UC patients and matched them based on their age at the time of diagnosis and follow-up at a median of 6 years (range 3-11 years) to serve as disease controls. Twenty children for whom inflammatory bowel disease (IBD) had been excluded as a result of endoscopy served as non-IBD controls. Colon biopsies taken by diagnostic endoscopy before the onset of therapy were stained using immunohistochemistry to study the expression of MMP-9, trypsinogen-1 (Tryp-1), Tryp-2, and a trypsin inhibitor (TATI). The profiles of these proteases and inhibitor at diagnosis were compared between the surgery group, the conservatively treated UC patients and the non-IBD controls.

RESULTS: The proportions of Tryp-1 and Tryp-2 positive samples in the colon epithelium and in the inflammatory cells of the colon stroma were comparable between the studied groups at diagnosis. Interestingly, the immunopositivity of Tryp-1 (median 1; range 0-3) was significantly lower in the epithelium of the colon in the pediatric UC patients undergoing surgery when compared to that of the conservatively treated UC patients (median 2; range 0-3; P = 0.03) and non-IBD controls (median 2; range 0-3; P = 0.04). For Tryp-2, there was no such difference. In the inflammatory cells of the colon stroma, the immunopositivities of Tryp-1 and Tryp-2 were comparable between the studied groups at diagnosis. Also, the proportion of samples positive for TATI, as well as the immunopositivity, was comparable between the studied groups in the colon epithelium. In the stromal inflammatory cells of the colon, TATI was not detected. In UC patients, there were significantly more MMP-9 positive samples and a higher immunopositivity in the stromal inflammatory cells of the colon when compared to the samples from the non-IBD patients (P = 0.006 and P = 0.002, respectively); the immunopositivity correlated with the histological grade of inflammation (95%CI: 0.22-0.62; P = 0.0002), but not with the other markers of active disease. There were no differences in the immunopositivity or in the proportions of MMP-9 positive samples when examined by epithelial staining. The staining profiles in the ileal biopsies were comparable between the studied groups for all of the studied markers.

CONCLUSION: For pediatric UC patients who require surgery, the immunopositivity of Tryp-1 at diagnosis is lower when compared to that of patients with a more benign disease course.

Tumour-associated trypsin inhibitor TATI is a prognostic marker in colorectal cancer

BACKGROUND

The tumour-associated trypsin inhibitor TATI is expressed together with trypsin in many cancer forms, and an elevated serum level associates with poor prognosis. TATI can reduce tissue destruction by inhibiting trypsin and other proteinases, and in some cancer forms, its high tissue expression is associated with favourable prognosis. We analyzed the prognostic values of TATI, trypsinogen-1 and trypsinogen-2 immunoexpression from tissue array blocks constructed from surgical specimens of 592 colorectal cancer patients.

RESULTS

TATI positivity correlated negatively with differentiation (p < 0.001) and positively with the histological type of adenocarcinoma (p < 0.001). Trypsinogen-1 and trypsinogen-2 positivity correlated with Dukes' stage (p = 0.045, p = 0.050); the percentage of trypsinogen-1- and trypsinogen-2-positive tumours was lower in metastasized (Dukes' stage C-D) than in local (Dukes' stage A-B) disease. In addition, trypsinogen-2 correlated inversely with differentiation (p = 0.012). In univariate analysis, the expression of TATI associated with more favourable cancer-specific survival (p = 0.010). In multivariate analysis, low TATI (p = 0.044), age (p < 0.001), Dukes' stage (p < 0.001), tumour differentiation (p = 0.020) and location in the rectum (p = 0.006) were independent prognostic factors for adverse outcome. Furthermore, TATI expression was an independent prognostic factor in a subgroup of trypsinogen-1- (p = 0.007) and trypsinogen-2-positive (p = 0.006) tumours.

CONCLUSION

TATI tissue expression is an independent prognostic marker in colorectal cancer.

Matrix metalloprotein-9 activation under cell-to-cell interaction between endothelial cells and monocytes: possible role of hypoxia and tumor necrosis factor-α

Matrix metalloproteinase (MMP)-9 plays an important role in cardiovascular events. However, the mechanisms underlying in vivo activation of MMP-9 are largely unknown. We investigated the secretion and activation of MMP-9 under a cell-to-cell interaction, and the effects of hypoxia and cytokine. Human umbilical vein endothelial cell (HUVEC) and THP-1 (human monocyte cell line) were cultured individually, or cocultured under normoxic and hypoxic conditions. In a coculture of HUVEC and THP-1, proMMP-9 secretion was increased twofold compared with individual culture of HUVEC and THP-1, whereas MMP-2 secretion was unchanged. The increase in proMMP-9 secretion was suppressed by antiadhesion molecule antibodies and mitogen-activated protein kinase inhibitors, PD98059 (MAPK/ERK kinase1 inhibitor) and SP600125 (Jun N-terminal kinase inhibitor). ProMMP-9 secretion was increased by tumor necrosis factor (TNF)-α at 50 ng/ml (P < 0.05) but was not activated under normoxic (20%) conditions. ProMMP-9 in coculture was activated under hypoxic (<1%) conditions, and was potentiated by TNF-α (both P < 0.05). To further investigate the mechanism of hypoxia-induced MMP-9 activation, heat shock protein (Hsp)90, which was suggested to be related to MMP-9 activation, was measured by Western blot analysis. The ratio of Hsp90 to glyceraldehyde-3-phosphate dehydrogenase was increased in hypoxic (<1%) coculture conditions with TNF-α (P < 0.05). Treatment with geldanamycin and 17-DMAG (Hsp90 inhibitor) suppressed the active form of MMP-9. Cell-to-cell interaction between endothelial cells and monocytes promotes proMMP-9 synthesis and secretion. Hypoxia and inflammation are suggested to play an important role in activating proMMP-9, presumably via Hsp90.

Regulation of matrix metalloproteinase activity in health and disease

The activity of matrix metalloproteinases (MMPs) is regulated at several levels, including enzyme activation, inhibition, complex formation and compartmentalization. Regulation at the transcriptional level is also important, although this is not a subject of the present minireview. Most MMPs are secreted and have their function in the extracellular environment. This is also the case for the membrane-type MMPs (MT-MMPs). MMPs are also found inside cells, both in the nucleus, cytosol and organelles. The role of intracellular located MMPs is still poorly understood, although recent studies have unraveled some of their functions. The localization, activation and activity of MMPs are regulated by their interactions with other proteins, proteoglycan core proteins and/or their glycosaminoglycan chains, as well as other molecules. Complexes formed between MMPs and various molecules may also include interactions with noncatalytic sites. Such exosites are regions involved in substrate processing, localized outside the active site, and are potential binding sites of specific MMP inhibitors. Knowledge about regulation of MMP activity is essential for understanding various physiological processes and pathogenesis of diseases, as well as for the development of new MMP targeting drugs.

Matrix metalloproteinases-7, -8, -9 and TIMP-1 in the follow-up of diisocyanate-induced asthma

BACKGROUND

Diisocyanate-induced asthma (DIA) is known to be associated with poor prognosis. We wished to clarify if matrix metalloproteinases (MMP)-7, -8 or -9 or tissue inhibitor of matrix metalloproteinases (TIMP-1) are associated with the functional or inflammatory outcome in DIA patients.

METHODS

This is a longitudinal study where 17 patients with DIA diagnosed by a specific challenge test to diisocyanates were monitored. Exposure to diisocyanates was terminated seven (mean) months before the challenge test. The studies included spirometry, histamine challenge test and bronchoscopy. MMP-7, MMP-8, TIMP-1 [Enzyme-linked immunosorbent assay (ELISA)- and immunofluorometric assay-methods], MMP-9 (ELISA and zymography), interferon-gamma, tumour necrosis factor-alpha, interleukin-6, -8, -15, -17, CXCL-5/ENA-78, monocyte chemoattractant protein-1 and macrophage inhibitory factor (MIF) (ELISA) were assayed from bronchoalveolar lavage (BAL) fluid. Inhaled steroid therapy was initiated after the examinations, which were repeated at 6 months and at 3 years during the treatment. The results were compared with those of 15 healthy controls.

RESULTS

Inhaled steroid medication increased BAL levels of MMP-9 and MMP-9/TIMP-1 and decreased MMP-7 and MMP-7/TIMP-1. The increase in MMP-9 levels was associated with a decline in the TH-2 type inflammation.

CONCLUSIONS

Our data suggest that reduced TH-2 type inflammation in DIA after inhaled steroid medication is reflected as elevated MMP-9 and MMP-9/TIMP-1 levels in BAL. MIF may be the inducer of MMP-9. This might point to some protective role for MMP-9 in DIA.

Urinary matrix metalloproteinase -8, -9, -14 and their regulators (TRY-1, TRY-2, TATI) in patients with diabetic nephropathy

Matrix metalloproteinase-9 (MMP-9) has been shown to be involved in the development of diabetic nephropathy (DNP). We studied the levels, molecular forms, and degree of activation of urinary MMP-8, -9, -14, trypsin-1 and -2, as well as tumor-associated trypsin inhibitor (TATI) of DNP patients and healthy controls. Urinary samples were analyzed for MMPs by Western blotting and gelatin zymography and for trypsin-1, -2, and TATI by time-resolved immunofluorometric assays. Total MMP-8 immunoreactivity, the proportion of active MMP-9, and gelatinolytic activity in urine were significantly higher in DNP patients than in controls. In urine of DNP patients the proportion of active polymorphonuclear neutrophil (PMN)-type (but not fibroblast-type) MMP-8 was increased. MMP-8 and MMP-9 were found to form high molecular weight complexes in DNP urine. Total immunoreactivity of soluble urinary MMP-14 and the levels of trypsin (TRY)-1 and TRY-2, but not of TATI, were also significantly increased in DNP. Zymography, Western blotting, and immunofluorometric analysis of DNP urine showed a significant association especially between activation of MMP-9 as well as PMN-type MMP-8 and TRY-2. Our findings suggest that a trypsin-MMP cascade is involved in the pathogenesis of DNP, which may offer new possibilities for diagnosis and treatment of DNP with MMP inhibitors.

Human beta-defensin-1 and -2 and matrix metalloproteinase-25 and -26 expression in chronic and aggressive periodontitis and in peri-implantitis

OBJECTIVE

Aberrant matrix metalloproteinase (MMP) and human beta-defensin (HBD) functions have been found in inflammatory diseases. The objectives of this study were to investigate the immunolocalisation, mRNA expression and molecular forms of MMP-25, MMP-26, HBD-1 and HBD-2 in chronic and aggressive periodontitis and in peri-implantitis. The expression of MMP-25 by cultured human plasmacytoma cells and macrophages, and the effects of MMP-26 and Porphyromonas gingivalis trypsin-like proteinase on HBD-1 and -2 were also studied.

DESIGN

Immunohistochemistry, immunofluorescent analysis, reverse transcriptase polymerase chain reaction and immunoblotting were used to assess localisation, mRNA expression and molecular forms of MMP-25, MMP-26, HBD-1 and HBD-2. HBD degradation by MMP-26 and P. gingivalis proteinase was studied by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

RESULTS

MMP-25 was present in plasma cells and polymorphonuclear leucocytes, and MMP-26 was present in oral and sulcular basement membrane zones. HBD-1 was distributed perivasculary in gingival connective tissue and in oral and sulcular epithelium, and HBD-2 was found to a lesser extent in the perivascular space. Low MMP-25, MMP-26, HBD-1 and HBD-2 mRNA expression was found. Immunoblot revealed 29-57-kDa MMP-25 in myeloma cell lysates, but not in macrophages, and partly activated MMP-25 and -26 in diseased gingival crevicular fluid and peri-implant sulcular fluid. P. gingivalis trypsin-like proteinase degraded HBD-1 and -2.

CONCLUSIONS

Both MMP-25 and -26 were expressed more strongly in extensively inflamed gingiva compared with healthy gingiva. The expression of HBD-1 was stronger than that of HBD-2 in periodontitis and peri-implantitis. De-novo expression of MMP-25 and -26 is associated with periodontal and peri-implant inflammation. Furthermore, P. gingivalis trypsin-like proteinase, but not MMP-26, can degrade HBD-1 and -2, which could lead to a weakened innate immune response.

Biochemistry and clinical role of trypsinogens and pancreatic secretory trypsin inhibitor

Trypsinogens and PSTI/TATI/SPINK1 are expressed, usually together, at high levels by the pancreas but also by many other normal and malignant tissues. The present review describes studies on the expression and putative functions of trypsinogens and PSTI/TATI/SPINK1 in the human body. The clinical aspects are discussed, including the correlations between expression of trypsinogens and PSTI/TATI/SPINK1 in tissues, serum, and urine of patients with pancreatitis or cancer and clinicopathological characteristics, i.e., the roles of trypsinogens and PSTI/TATI/SPINK1 in spontaneous and hereditary pancreatitis, tumor progression, and prognosis.

Levels and Activation of Matrix Metalloproteinases in Aqueous Humor Are Elevated in Uveitis-Related Secondary Glaucoma

PURPOSE

To measure the levels of matrix metalloproteinase (MMP)-2 and tissue inhibitors of metalloproteinases (TIMP)-2 and to study the expression pattern and molecular forms of MMP-2, 8, 9, 13, and 14 and TIMP-1 and 2 in aqueous humor samples in cases of uveitis-related secondary glaucoma (USG) with a history of up to 20 years by comparison with primary open-angle glaucoma (POAG) and cataracts.

METHODS

33 aqueous humor samples were collected during intraocular surgery. MMP-2 and TIMP-2 levels were analyzed by enzyme-linked immunosorbent assay. Molecular forms and activation degrees of MMPs and TIMPs were analyzed by Western immunoblotting and zymography. The results were related to the clinical data.

RESULTS

Enzyme-linked immunosorbent assay measurements of both MMP-2 and TIMP-2 were statistically significantly increased in the USG samples relative to POAG and cataracts (P=0.002). In Western blotting all the MMPs showed increased expression and conversion to their active forms in USG, whereas in the POAG and cataract samples MMPs were found mainly in their latent forms. MMP-8, 9, 13, and 14 showed statistically significantly elevated expression in USG relative to POAG and cataracts on densitometric scanning of Western blots. On zymography, MMP-2 and 9 activation was significantly enhanced in USG compared with POAG and cataracts.

CONCLUSIONS

Increased expression of MMPs and their conversion to active forms is characteristics of the aqueous humor in USG, even with a very long history. This emphasizes the fact that increased MMP expression reflects inflammatory disease activity and is probably associated with the development of USG and its complications. Although intraocular pressure is elevated in both glaucoma types, MMP expression in POAG more closely resembles that in cataracts, and therefore the role of MMPs in USG differs very markedly from that in POAG.

Gingival Crevicular Fluid Matrix Metalloproteinase-25 and -26 Levels in Periodontal Disease

BACKGROUND

Tissue destruction associated with the progression of periodontal disease is caused by a cascade of host and microbial proteolytic enzymes. Host-derived matrix metalloproteinases (MMPs) play an important role in the degradation of the extracellular matrix. Leukolysin/membrane-type 6 (MT-6)/MMP-25, the latest member of the MT-MMP subgroup of the MMP family, is primarily expressed by neutrophils and involved in extracellular matrix turnover. Matrilysin-2/MMP-26 (endometase), a novel member of the matrilysin subgroup of the MMP family, can degrade the extracellular matrix, alpha1-antitrypsin, and activate pro-MMP-9. Our study aimed to examine the levels, molecular forms, and degrees of activation of MMP-25 and MMP-26 in gingival crevicular fluid (GCF) from patients with different periodontal diseases.

METHODS

A total of 105 subjects, 35 with generalized aggressive periodontitis (GAgP), 29 with chronic periodontitis (CP), 20 with gingivitis, and 21 periodontally healthy subjects, were included in this study. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, presence of bleeding on probing, and plaque. GCF MMP-25 and MMP-26 levels were analyzed by computer-quantitated Western immunoblotting using specific antibodies.

RESULTS

The 57-kDa soluble pro-MMP-25 and 45- to 47-kDa active form of MMP-25 were detected by Western immunoblots in CP and GAgP GCF, and lesser levels of these soluble MMP-25 immunoreactive bands were detected in gingivitis GCF. An enhanced and similar degree of MMP-25 activation was found in GAgP, CP, and gingivitis groups. There were no detectable MMP-25 immunoreactivities in the healthy subjects' GCF. GAgP and CP groups had elevated GCF MMP-26 levels and degrees of activation compared to the gingivitis and healthy groups (P <0.008). The gingivitis group had higher GCF MMP-26 levels and degree of activation compared to the healthy group (P <0.008).

CONCLUSIONS

The present study demonstrated the presence of soluble or shed forms of MMP-25 and MMP-26 in GCF of patients with different periodontal diseases. Increased levels and activation of MMP-25 and MMP-26 in GCF are associated with an enhanced severity of periodontal inflammation, suggesting that these novel MMPs can participate in the progression of periodontal diseases. They may prove to be diagnostically useful and could be targets of medication in the future.

Urinary Levels of Tumor-Associated Trypsin Inhibitor (TATI) in the Detection of Transitional Cell Carcinoma of the Urinary Bladder

OBJECTIVE

To assess whether urinary levels of tumor-associated trypsin inhibitor (TATI) would aid in the detection of bladder transitional cell carcinoma (TCC); and to compare diagnostic performance of urinary TATI with that of nuclear matrix protein 22 (NMP22) and barbotage cytology.

METHODS

We determined TATI and NMP22 levels in voided urine from 181 subjects: 153 with previous bladder cancer, 20 with urologic pathology other than bladder cancer, and eight healthy volunteers. TATI was analyzed continuously and categorically on the basis of its quartile distribution. We also measured urinary creatinine and barbotage cytology in 173 and 154 patients, respectively.

RESULTS

Urinary TATI levels were significantly higher in TCC patients with evidence of tumor on cystoscopic evaluation (n = 96) than in control subjects (n = 85; p < 0.001). Higher levels of TATI were associated with positive cytology assay results (p = 0.018), higher NMP22 levels (p < 0.001), and invasive tumor stage (p = 0.026). The area under the receiver operating characteristics (ROC) curve (AUC) of TATI for the detection of TCC was 0.712 (95%CI: 0.637-0.786). The overall AUCs for TATI and NMP22 were not statistically different from each other (p = 0.174). In the >75% sensitivity region of the ROC curves, TATI was consistently more specific than NMP22. TATI, NMP22, and cytology were independently associated with bladder cancer (p = 0.049, p = 0.040, and p < 0.001, respectively). Adjustment of TATI for urinary creatinine levels did not affect any of the outcomes.

CONCLUSIONS

Urinary level of TATI may add independent information to urinary cytology and NMP22 in the detection of bladder TCC. TATI seems to outperform NMP22 for bladder TCC detection.

Pancreatic trypsin activates human promatrix metalloproteinase-2

In contrast to the prevalent view in the literature hitherto, the present study shows that pancreatic trypsin can activate human promatrix metalloproteinase-2 (proMMP-2). It is shown that trypsin's ability to activate proMMP-2 is dependent on various environmental factors such as the level of exogenously added Ca(2+) and Brij-35, temperature, as well as trypsin concentration. The activation occurred as a sequential processing of the proenzyme, initially generating an active 62kDa species. This was followed by successive truncation of the C-terminal domain, giving rise to active species of 56kDa, 52kDa and 50kDa. Tissue inhibitor of matrix metalloproteinases-2 (TIMP-2) prevented the trypsin-mediated C-terminal truncation, without affecting the generation of the 62kDa species, while the presence of EDTA increased the rate of the trypsin-mediated activation of proMMP-2. MALDI-TOF MS analysis of the 50kDa form indicated that trypsin generated active forms with either Lys87 or Trp90 as the N-terminal residue and Arg538 as a C-terminal residue. The trypsin-activated MMP-2 was active in solution against both synthetic and physiologic substrates, and the steady-state kinetic coefficients k(cat), K(m) and k(cat)/K(m) were determined for the enzyme activated either by APMA, membrane-type 1 matrix metalloproteinase (MT1-MMP) or trypsin. The trypsin-activated MMP-2 exhibited slightly lower k(cat) and k(cat)/K(m) values as well as a slightly higher K(i) value against TIMP-1 compared to the enzyme activated by APMA or MT1-MMP. Docking studies of TIMP-1 revealed that the slightly weaker binding of the inhibitor to the trypsin-activated MMP-2 could be attributed to its shorter N terminus (Lys87/Trp90 versus Tyr81), as Phe83 and Arg86 interacted directly with the inhibitor. Our results suggest that the trypsin-activated MMP-2 possesses the catalytic and regulatory potential to be of significance in vivo.

Matrix metalloproteinases and their tissue inhibitors in aqueous humor of patients with primary open-angle glaucoma, exfoliation syndrome, and exfoliation glaucoma

PURPOSE

To study extracellular matrix (ECM) metabolism by matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in aqueous humor (AH) samples collected from primary open-angle glaucoma (POAG), exfoliation syndrome (EXS), and exfoliation glaucoma (EXG) in relation to samples derived from cataract control patients.

MATERIALS AND METHODS

Seventy-one AH samples were collected during cataract extraction and trabeculectomy. The expression and molecular forms of MMP-2, -8, -9, -13, and -14 and tissue inhibitor of metalloproteinases-1 and -2 (TIMPs) were analyzed by Western immunoblotting. Gelatinase and collagenase activities were studied by zymography and type I collagen degradation assays, respectively. MMP-2 and TIMP-2 concentrations were measured by ELISA assays.

RESULTS

By Western immunoblotting all the studied MMPs were mainly in their latent form in all diagnostic groups. Zymography demonstrated that MMP-2 represents the major gelatinase in AH. Similarly, type I collagenolytic activity was low and similar in cataract and glaucoma samples. In ELISA measurements the TIMP-2 levels were significantly elevated in glaucoma and EXS samples in comparison to cataract controls (P < 0.05).

CONCLUSION

TIMP-2 is elevated in glaucomatous process over MMP-2, which support and further extend the conjuncture that the ECM accumulation rather than degradation predominates in the pathogenesis of POAG and EXG.

Expression of trypsinogen-1, trypsinogen-2, and tumor-associated trypsin inhibitor in ovarian cancer: prognostic study on tissue and serum

PURPOSE

The purpose is to study the prognostic significance of tissue expression of trypsinogen-1, trypsinogen-2, and tumor-associated trypsin inhibitor (TATI) and serum concentration of trypsinogen-2, trypsin-2-API (complex of trypsin-2 with alpha-1-proteinase inhibitor), and TATI in epithelial ovarian cancer.

EXPERIMENTAL DESIGN

Expression of trypsinogen-1, trypsinogen-2, and TATI was determined by immunohistochemistry with monoclonal antibodies in tissue sections of tumors from 119 patients with untreated primary epithelial ovarian cancer. Preoperative serum concentrations of trypsinogen-2, trypsin-2-API and TATI were analyzed using specific immunoassays.

RESULTS

Fifty-four percent of the tumors expressed trypsinogen-1, 45% expressed trypsinogen-2, and 30% expressed TATI. In patients with stage III and IV disease, TATI tissue expression (P = 0.002) and elevated TATI concentration in serum (P = 0.048) were associated with adverse cancer-specific and progression-free survival in univariate analysis. In multivariate analysis, TATI tissue expression (P = 0.005), tumor grade (P = 0.0001), histological type (P = 0.02), and stage (P = 0.0005) were independent prognostic factors for adverse cancer-specific survival and TATI tissue expression (P = 0.006) and grade (P = 0.0003) for progression-free survival. In multivariate analysis of all patients and those with advanced disease, serum trypsin-2-API concentration was an adverse prognostic factor for cancer-specific and progression-free survival, and it was independent of stage and histological type of the tumor (P <or= 0.01).

CONCLUSIONS

Tissue expression of TATI and an elevated preoperative serum concentration of trypsin-2-API are strong independent prognostic factors in advanced epithelial ovarian cancer. These results suggest that trypsin expression plays a role in the progression of ovarian cancer. TATI and trypsin-2-API are of potential use as an aid for stratification of randomized studies and for selecting treatment strategies.

Pulmonary trypsin-2 in the development of bronchopulmonary dysplasia in preterm infants

OBJECTIVES

In the preterm infant, lung injury can lead to irreversible tissue destruction and abnormal lung development. We examined whether pulmonary trypsin, a potent matrix-degrading serine proteinase and proteinase-cascade activator, is associated with the development of bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

Samples of tracheal aspirate fluid were collected from 32 intubated preterm infants during their first 2 postnatal weeks. The presence and molecular forms of trypsin in tracheal aspirate fluid samples were analyzed by zymography and Western blotting. The concentrations of trypsinogen-1 and -2 and tumor-associated trypsin inhibitor were measured by immunofluorometry. For examining the expression of trypsin-2 in lung tissue, immunohistochemistry was performed on autopsy specimens of fetuses, of preterm infants who died from respiratory distress syndrome or BPD, and of term infants without lung injury.

RESULTS

In infants who subsequently developed BPD (n = 18), we detected significantly higher concentrations of trypsinogen-2 during postnatal days 5 to 10 compared with those who survived without it. There was no difference in trypsinogen-1 concentrations. Tumor-associated trypsin inhibitor concentrations were significantly lower in infants who needed mechanical ventilation for >1 week. Immunohistochemistry demonstrated that trypsin-2 was predominantly expressed in bronchial and bronchiolar epithelium. In 2 preterm infants who died from prolonged respiratory distress syndrome, trypsin-2 was also expressed in vascular endothelium.

CONCLUSIONS

The levels of trypsinogen-2 are higher during postnatal days 5 to 10 in infants who subsequently develop BPD. The results suggest that high levels of pulmonary trypsin-2 may be associated with the development of BPD. This raises the possibility that therapy with exogenous proteinase inhibitors might prevent the development of BPD in preterm infants with respiratory distress.

Endostatin inhibits human tongue carcinoma cell invasion and intravasation and blocks the activation of matrix metalloprotease-2, -9, and -13

Endostatin, a 20-kDa collagen XVIII fragment, inhibits angiogenesis and tumor growth in vivo, but the mechanisms are still unclear. Matrix metalloproteases (MMPs), a family of extracellular and membrane-associated endopeptidases, collectively digest almost all extracellular matrix and basement membrane components, and thus play an important role in tumor progression. We studied the effects of recombinant human endostatin on human MMP-2, -9, -8, and -13. We found that endostatin inhibited the activation and catalytic activity of pro-MMP-9 and -13 as well as recombinant pro-MMP-2. It prevented the fragmentation of pro-MMP-2 that was associated with reduction of catalytic activity. Endostatin had no effect on MMP-8 as shown by collagenase activity assays. An in vitro migration assay and an in vivo chicken chorioallantoic membrane intravasation assay with the human tongue squamous cell carcinoma cell line HSC-3 revealed the biphasic nature of endostatin; low endostatin concentrations inhibited intravasation and migration of these cells in a dose-dependent manner, but at increased concentrations, the inhibitory effect was far less efficient. The results show that endostatin blocks the activation and activities of certain tumor-associated pro-MMPs, such as pro-MMP-2, -9, and -13, which may explain, at least in part, the antitumor effect of endostatin. Our results also suggest that endostatin inhibits tumor progression by directly affecting the tumor cells and not just acting via endothelial cells and blockage of angiogenesis.

Tumor-associated trypsinogen-2 (trypsinogen-2) activates procollagenases (MMP-1, -8, -13) and stromelysin-1 (MMP-3) and degrades type I collagen

A critical step in cancer growth and metastasis is the dissolution of the extracellular matrix surrounding the malignant tumor, which leads to tumor cell invasion and dissemination. Type I collagen degradation involves the initial action of collagenolytic matrix metalloproteinases (MMP-1, -8, and -13) activated by MMP-3 (stromelysin-1). The role of interactive matrix serine proteinases (MSPs), including tumor-associated trypsinogens, has been unclear in collagenolysis. Now, we provide evidence that the major isoenzyme of human tumor-associated trypsinogens, trypsin-2, can directly activate three collagenolytic proMMPs as well as proMMP-3. These proMMP activations are inhibited by tumor-associated trypsin inhibitor (TATI). Furthermore, we demonstrate that trypsin-2 efficiently degrades native soluble type I collagen, which can be inhibited by TATI. However, cell culture studies showed that trypsin-2 transfection into the HSC-3 cell line did not result in MMP-1, -3, -8, and -13 activation but affected MMP-3 and -8 production at the protein level. These findings indicate that human trypsin-2 can be regarded as a potent tumor-associated matrix serine protease capable of being the initial activator of the collagenolytic MMP activation network as well as directly attacking type I collagen.

MMP-9 activation by tumor trypsin-2 enhances in vivo invasion of human tongue carcinoma cells

Various human cancer cells express tumor-associated trypsinogen-2 (TAT-2), which can efficiently activate matrix metalloproteinases (MMPs) in vitro. MMP-2 and MMP-9 are particularly associated with the invasive malignant potential of several tumors. To investigate the role of TAT-2 in tumor invasion, we overexpressed TAT-2 in two malignant human squamous cell carcinoma cell lines of tongue and in non-malignant human papilloma virus transformed gingival keratinocytes. The TAT-2 overexpression significantly increased the levels of active MMP-9 in the most malignant cell line. TAT-2-transfected cells intravasated (invaded blood vessels) up to 60% more efficiently than did the control cells in an in vivo chick embryo chorioallantoic membrane invasion model. This increased intravasation was almost completely abolished by a specific tumor-associated trypsin inhibitor (TATI). These results indicate that TAT-2 has a role in the invasive growth of tumors, either alone or in cascade with gelatinases, especially by generating active MMP-9.