The distribution of matrix metalloproteinases and tissue inhibitor of metalloproteinases in colorectal cancer

Mapping the Binding Sites of MMPs on Types II and III Collagens Using Triple-Helical Peptide Toolkits

Libraries of triple-helical collagen-like peptides (Collagen Toolkits) have helped to define collagens II and III binding specificities of numerous collagen-binding proteins. Here I describe a simple solid-phase binding assay utilizing a biotin-streptavidin system to screen the Collagen Toolkits for binding of two distinct matrix metalloproteinases (MMPs) implicated in cancer: the collagenolytic MMP1 (collagenase 1) and the non-collagenolytic MMP3 (stromelysin 1). The screening revealed markedly disparate binding footprints of these MMPs on collagens II and III, in line with their distinct biological activities. Analogous screening of other potentially collagen-binding proteases may shed light on their inherent tissue retention capabilities and their pro- or anti-metastatic potential.

Colorectal cancer diagnostic biomarkers: Beyond faecal haemoglobin

Colorectal cancer (CRC) is the third most common cancer worldwide, and the second commonest cause of cancer deaths worldwide. One of the most important prognostic factors, and thus a potential target for improving cancer care, is the stage of cancer at diagnosis. Earlier stage diagnosis is associated with better prognosis and longer survival times after treatment. At the same time, the use of targeted therapies and immunotherapy is improving CRC outcomes. Diagnostic biomarkers are key to both early detection and prediction of treatment responses. Currently faecal immunochemical testing for haemoglobin is perhaps the most widespread CRC diagnostic biomarker. However other biomarkers are approved for clinical use and others are in the validation stage of research prior to clinical use. This review focuses on these the evidence behind these biomarkers, their current and potential future use.

Structural studies of the MMP-3 interaction with triple-helical collagen introduce new roles for the enzyme in tissue remodelling

Matrix metalloproteinase-3 (MMP-3) participates in normal extracellular matrix turnover during embryonic development, organ morphogenesis and wound healing, and in tissue-destruction associated with aneurysm, cancer, arthritis and heart failure. Despite its inability to cleave triple-helical collagens, MMP-3 can still bind to them, but the mechanism, location and role of binding are not known. We used the Collagen Toolkits, libraries of triple-helical peptides that embrace the entire helical domains of collagens II and III, to map MMP-3 interaction sites. The enzyme recognises five sites on collagen II and three sites on collagen III. They share a glycine-phenylalanine-hydroxyproline/alanine (GFO/A) motif that is recognised by the enzyme in a context-dependent manner. Neither MMP-3 zymogen (proMMP-3) nor the individual catalytic (Cat) and hemopexin (Hpx) domains of MMP-3 interact with the peptides, revealing cooperative binding of both domains to the triple helix. The Toolkit binding data combined with molecular modelling enabled us to deduce the putative collagen-binding mode of MMP-3, where all three collagen chains make contacts with the enzyme in the valley running across both Cat and Hpx domains. The observed binding pattern casts light on how MMP-3 could regulate collagen turnover and compete with various collagen-binding proteins regulating cell adhesion and proliferation.

Assessment of gelatinase expression and activity in articular cartilage

Two methods for the assessment of the expression of gelatinases A and B, MMP-2 and MMP-9, in articular cartilage are described. Immunohistochemical analysis of tissue sections provides information about the precise localization of the enzymes within the tissue, pinpointing the cells that synthesize the proteinases, and zymography of cell/ tissue conditioned culture media allows a semi-quantitative assessment of the gelatinases and their activation status.

Elevated serum matrix metalloproteinase 9 (MMP-9) concentration predicts the presence of colorectal neoplasia in symptomatic patients

Early detection of polyps or colorectal carcinoma can reduce colorectal carcinoma-associated deaths. Previous studies have demonstrated raised serum levels of matrix metalloproteinase 9 (sMMP-9) in a range of cancers. The aim of this study was to investigate the role of sMMP-9 levels in identifying colorectal neoplasia. Consenting patients donated a blood sample and were assessed by proforma-led history and physical examination. Samples were analysed for sMMP-9 concentration (enzyme-linked immuno-sorbant assay) and compared to final diagnoses. Logistic regression modelling determined independent factors associated with neoplasia. A total of 365 patients were recruited of whom 300 were analysed, including 46 normal controls. A total of 27 significant adenomas and 63 malignancies were identified. The median sMMP-9 concentration was 443ng ml⁻¹ (IQR: 219–782; mean: 546). Patients with neoplasia had significantly elevated sMMP-9 levels (P<0.001). Logistic regression modelling identified elevated log(sMMP-9) as the most significant predictor of neoplasia (χ²=38.33, P<0.001). Other significant factors were age, sex, smoking history, abdominal pain and weight loss. The model accurately predicted neoplasia in 77.3% of cases. Sensitivity and specificity were 77.9 and 77.1%. sMMP-9 estimation can accurately stratify patient to low- or high-risk cohorts. Serum sampling is a potential means of avoiding unnecessary colonoscopy and reducing patient anxiety, iatrogenic morbidity and mortality, and cost.

Matrix metalloproteinase distribution during early corneal wound healing

AIM

To compare matrix metalloproteinase (MMP) localisation in anterior keratectomy (AK) and lamellar keratectomy (LK) wounds.

METHODS

Wounds were produced in one eye of 24 rabbits. The AK wounds were made to approximately 120 microm in depth and then allowed to re-epithelialise. The LK wounds were of similar depth, but the anterior stroma and epithelium were replaced after a second deeper keratectomy had been performed. Immunohistochemistry was used to localise the MMP-1, -2, -3, and -9 at intervals from 4 h to 14 days following surgery. The contralateral eyes acted as controls.

RESULTS

After an AK wound MMP-1 was present at the leading edge of migrating epithelium after 18 h, while MMP-2 and -9 were localised behind the advancing epithelial edge. The presence of these enzymes rapidly fell to low levels after epithelial closure. There was only faint MMP-3 localisation between days 3 and 7. After an LK wound, MMP-1, -3, and -9 were not detected in the stromal interface, but MMP-2 was present at all time points.

CONCLUSIONS

This study suggests that after an AK wound, MMP-1 is a key mediator of epithelial migration, while MMP-2 and -9, and to a lesser extent MMP-3, may participate in the remodelling of corneal stroma and the reformation of epithelial basement membrane. In contrast, an LK wound results in a much lower stimulus for MMP activation. The action of MMP-2 in stromal repair is thus partly independent of epithelial injury.

Expression of matrix metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and -2) in prostate cancer tissue

Matrix metalloproteinases (MMPs) have been implicated in progression and metastases of different tumours. The balance between the MMPs and their natural inhibitors (tissue inhibitors of matrix metalloproteinases; TIMP) seems to be an important factor related to this role. Here, the expression of MMP-2 and -9 along with TIMP-1 and -2 was examined in prostate cancer tissue. A total of 40 radical prostatectomy specimens were embedded in paraffin and immunohistochemical staining was performed to detect MMP-2 and -9, and TIMP-1 and -2. The immunoreactivity was assessed semiquantitively using routine light microscopy. The intensity of staining was correlated to preoperative PSA, T category, Gleason score and clinical parameters of the specimens. The imbalance of MMPs and TIMPs was recognised as a significant loss of TIMP-1 in malignant epithelium and an upregulation of MMPs. Palpable tumours (T2, T3) expressed significantly more MMP-2 and significantly less MMP-9 than T1c tumours. Our data are in accordance with other literature reports in that an imbalance of MMPs and TIMPs is found in malignant tumours. The observed imbalance of MMP and TIMP is mainly caused by a loss of TIMP-1. Furthermore, palpable tumours demonstrated significantly more MMP-2 and significantly less MMP-9 expression than nonpalpable tumours.

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

OBJECTIVE

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

SAMPLE POPULATION

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

PROCEDURE

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

RESULTS

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

CONCLUSIONS AND CLINICAL RELEVANCE

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

Measuring gelatinase activity in colorectal cancer

AIMS

Gelatinases (MMP-2, -9) are the most extensively studied MMPs in cancer. The aim of the study was to determine the levels of active and latent forms of the gelatinases in paired colorectal tumour and normal tissue ( n=77) and correlate these with pathological stage.

METHODS

Gelatinase levels were compared following the techniques of gelatin zymography (active and latent) and the novel gelatinase activity assays (total and endogenous/active).

RESULTS

Both latent and active MMP-2 and MMP-9 lysis bands (zymography) and both total (active and latent) MMP-9 and endogenous (active) MMP-9 and MMP-2 levels (activity assays) were greater in tumour than normal colorectal tissue. Total MMP-2 and MMP-9 levels as determined by activity assays correlated with both the Dukes staging (e.g. total MMP-9 in tumours: adenoma, 1.0 (0.3--3.6); Dukes A, 9.6 (2.4--35.4); Dukes B, 14.7 (1.5--103.9); Dukes C, 22.3 (2.2--57.9) and Dukes D, 37.4 (2.1--47.0) ng/mg protein) and with lymphatic invasion (e.g. total MMP-9; in tumours which had undergone lymphatic invasion, 22.7 (2.1--57.9) and those with no lymphatic invasion, 14.0 (1.5--103.9) ng/mg protein).

CONCLUSIONS

Both gelatinases were upregulated in tumour tissue, however total and not endogenous active levels correlated with the pathological stage of the tumour. Therefore gelatinases may only be activated when required for tumour invasion and metastasis.

Matrix metalloproteinases, their tissue inhibitors and colorectal cancer staging

BACKGROUND

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are important in tumour invasion and metastasis. The levels of MMPs, TIMPs and total MMP activity were compared in paired colorectal tumour (n = 50) and normal tissue (n = 49) samples and correlated with clinical and pathological staging.

METHODS

Gelatin zymography (MMP-2 and MMP-9), enzyme-linked immunosorbent assays (MMP-1, MMP-3, TIMP-1 and TIMP-2) and quenched fluorescent substrate hydrolysis (total MMP activity) were employed in resection specimens from 50 patients, four with adenomas and 46 with colorectal cancer.

RESULTS

The levels of active MMP-2 and MMP-9 and total MMP-1, MMP-3 and TIMP-1 were significantly greater in tumour tissue than in normal colon (e.g. TIMP-1 tumour median 72 (range 25-351) versus normal 26 (4-107) ng per mg total protein content; P<0.05); however, TIMP-2 levels were significantly greater in normal tissue (P<0.05). Total MMP activity was significantly greater in tumour than in normal tissue (15 025 (1750-174 400) versus 7250 (750-354 650) pmol l-1 min-1 mg protein-1; P<0.05). Correlations were found between both MMP and TIMP levels and pathological tumour staging. MMP-1 appeared to be most important as its concentration correlated positively with Dukes staging, tumour differentiation and lymphatic invasion.

CONCLUSION

The levels of the studied MMPs and total MMP activity were upregulated in colorectal tumours. MMP-1 is important in colorectal cancer progression.

Matrix metalloproteinases: biologic activity and clinical implications

Tumor progression is a complex, multistage process by which a normal cell undergoes genetic changes that result in phenotypic alterations and the acquisition of the ability to spread and colonize distant sites in the body. Although many factors regulate malignant tumor growth and spread, interactions between a tumor and its surrounding microenvironment result in the production of important protein products that are crucial to each step of tumor progression. The matrix metalloproteinases (MMPs) are a family of degradative enzymes with clear links to malignancy. These enzymes are associated with tumor cell invasion of the basement membrane and stroma, blood vessel penetration, and metastasis. They have more recently been implicated in primary and metastatic tumor growth and angiogenesis, and they may even have a role in tumor promotion. This review outlines our current understanding of the MMP family, including the association of particular MMPs with malignant phenotypes and the role of MMPs in specific steps of the metastatic cascade. As scientific understanding of the MMPs has advanced, therapeutic strategies that capitalize on blocking the enzymes have rapidly developed. The preclinical and clinical evolution of the synthetic MMP inhibitors (MMPIs) is also examined, with the discussion encompassing important methodologic issues associated with determining clinical efficacy of MMPIs and other novel therapeutic agents.

Proteolysis in human breast and colorectal cancer

Proteolysis occurs when proteinase activity exceeds inhibitor activity. Proteolysis is normally tightly regulated and is involved in cancer invasion and metastasis. The aim of this study was to compare proteolysis in breast and colorectal cancer. Proteinase and inhibitor expression were analysed in paired tumour and normal tissue samples from 43 breast and 24 colorectal cancer patients using substrate zymography, Western blotting and quenched fluorescence substrate hydrolysis. The expression of the latent forms of matrix metalloproteinase-2 (MMP-2), MMP-3 and MMP-9, urokinase plasminogen activator (uPA), tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 expression were observed in both tumour and normal tissue samples from breast and colorectal tissue; however, expression was greater in the tumour tissue. Expression of active MMP-2 and MMP-9 and the total MMP activity were greater in tumour compared to normal samples in both tissues (P < 0.05). The expression of all proteinases and total MMP activity was greater in colorectal tissue than breast tissue samples. Breast and colorectal cancer demonstrated different proteinase profiles, however proteolysis in both tissues was greater in tumour tissue than normal tissue.

Proteolysis in colorectal cancer

BACKGROUND

The process of metastasis is complex, involving many interrelated stages, including proteolysis. Proteolysis occurs in both normal and pathological processes and involves the breakdown of the extracellular matrix and/or basement membrane by proteolytic enzymes. Normally, proteolysis is tightly controlled by specific endogenous proteinase inhibitors. However, in certain disease processes, including cancer, controlled but abnormal proteolysis seems to occur. Proteinases involved in tumour invasion and metastasis include the matrix metalloproteinases (MMPs) and the serine proteinases.

AIMS

To gain a greater understanding of the proteolytic process occurring in colorectal cancer and to determine which, if any, proteinases are upregulated.

METHODS

The synthesis of proteinases and their inhibitors was compared in paired tumour and normal tissue samples from patients with colorectal cancer (n = 24). Substrate zymography was used to determine the synthesis of MMPs (MMP-2, MMP-9, and MMP-3) and the plasminogen activators (urokinase and tissue-type plasminogen activators); enzyme linked immunosorbent assays (ELISAs) were used to determine the concentrations of MMP-1 and tissue inhibitor of metalloproteinase 1 (TIMP-1); and the technique of quenched fluorescence substrate hydrolysis was performed to determine the total MMP activity of each sample.

RESULTS

In general, both proteinase and inhibitor expression was greater in the tumour tissue when compared with the corresponding normal colorectal tissue. The amount of active MMPs was greater in the tumour tissue.

CONCLUSIONS

The increased extracellular proteinase concentrations and activity may encourage tumour invasion and metastasis. This study points to MMP-9 as being of potential major importance in the development of this form of cancer.

Matrix metalloproteinases and the development of cancer

Proteolytic remodeling of the extracellular matrix is an important aspect of the creation and progression of cancer. Matrix metalloproteinases are important at several points during multi-stage neoplastic progression in tumor cells and responding blood vessels, inflammatory cells and stroma.