Validation of Selected Head and Neck Cancer Prognostic Markers from the Pathology Atlas in an Oral Tongue Cancer Cohort.

The Pathology Atlas is an open-access database that reports the prognostic value of protein-coding transcripts in 17 cancers, including head and neck cancer. However, cancers of the various head and neck anatomical sites are specific biological entities. Thus, the aim of the present study was to validate promising prognostic markers for head and neck cancer reported in the Pathology Atlas in oral tongue squamous cell carcinoma (OTSCC). We selected three promising markers from the Pathology Atlas (CALML5, CD59, LIMA1), and analyzed their prognostic value in a Norwegian OTSCC cohort comprising 121 patients. We correlated target protein and mRNA expression in formalin-fixed, paraffin-embedded cancer tissue to five-year disease-specific survival (DSS) in univariate and multivariate analyses. Protein expression of CALML5 and LIMA1 were significantly associated with five-year DSS in the OTSCC cohort in univariate analyses (p = 0.016 and p = 0.043, respectively). In multivariate analyses, lymph node metastases, tumor differentiation, and CALML5 were independent prognosticators. The prognostic role of the other selected markers for head and neck cancer patients identified through unbiased approaches could not be validated in our OTSCC cohort. This underlines the need for subsite-specific analyses for head and neck cancer.

Tumor budding score predicts lymph node status in oral tongue squamous cell carcinoma and should be included in the pathology report.

BACKGROUND: The majority of oral cavity cancers arise in the oral tongue. The aim of this study was to evaluate the prognostic value of tumor budding in oral tongue squamous cell carcinoma, both as a separate variable and in combination with depth of invasion. We also assessed the prognostic impact of the 8th edition of the American Joint Committee on Cancer's TNM classification (TNM8), where depth of invasion (DOI) supplements diameter in the tumor size (T) categorization. METHODS: Patients diagnosed with primary oral tongue squamous cell carcinoma were evaluated retrospectively. Spearman bivariate correlation analyses with bootstrapping were used to identify correlation between variables. Prognostic value of clinical and histopathological variables was assessed by Log rank and Cox regression analyses with bootstrapping using 5-year disease specific survival as outcome. The significance level for the hypothesis test was 0.05. RESULTS: One-hundred and fifty patients had available material for microscopic evaluation on Hematoxylin and Eosin-stained slides and were included in the analyses. Reclassification of tumors according to TNM8 caused a shift towards a higher T status compared to the previous classification. The tumor budding score was associated with lymph node metastases where 23% of the patients with low-budding tumors had lymph node metastases, compared with 43% of those with high-budding tumors. T-status, lymph node status, tumor budding, depth of invasion, and the combined tumor budding/depth of invasion score were all significantly associated with survival in univariate analyses. In multivariate analyses only N-status was an independent prognosticator of survival. CONCLUSION: Reclassification according to TNM8 shifted many tumors to a higher T-status, and also increased the prognostic value of the T-status. This supports the implementation of depth of invasion to the T-categorization in TNM8. Tumor budding correlated with lymph node metastases and survival. Therefore, information on tumor budding can aid clinicians in treatment planning and should be included in pathology reports of oral tongue squamous cell carcinomas.

A combined histo-score based on tumor differentiation and lymphocytic infiltrate is a robust prognostic marker for mobile tongue cancer.

We wanted to evaluate the prognostic value of common histopathological variables in a large cohort of patients with cancer in the mobile tongue as such information can be important for treatment stratification of the individual patient, especially for patients with low-stage disease. In addition, we wanted to investigate whether an alternative scoring model with fewer options would compromise the prognostic value. One hundred fifty patients with oral tongue squamous cell carcinomas that were treated in curative intent and with available HE-stained tumor sections were included. We reclassified all tumors and performed univariate and multivariate survival analyses of histopathological and clinical variables. For the complete cohort, lymph node status, grade of differentiation, perineural infiltration, and lymphocytic infiltration were independent prognosticators. In the low-stage disease group, independent prognostic factors were tumor size, grade of differentiation, and lymphocytic infiltrate. For patients with low-stage disease, a histo-score combining the scores for tumor differentiation and lymphocytic infiltrate identified a group of patients with particularly low survival, as patients with moderately or poorly differentiated tumors and little lymphocytic infiltrate had a less favorable 5-year survival outcome than patients in the high-stage disease group. This study shows that a histo-score combining tumor differentiation and lymphocytic infiltration should be given special consideration in treatment planning. Our results also illustrate that many variables can be scored with fewer options than previously suggested to increase their reproducibility, and still maintain their prognostic value.

Loss of S100A14 expression at the tumor-invading front correlates with poor differentiation and worse prognosis in oral squamous cell carcinoma.

BACKGROUND: We previously showed a tumor-suppressive function of S100A14 in oral squamous cell carcinoma (OSCC). This study aimed to examine the prognostic significance and differentiation-related function of S100A14 in OSCC. METHODS: S100A14 expression was examined in 170 OSCCs from Norwegian and Nepalese populations using immunohistochemistry. Pro-differentiation function was investigated by overexpressing and silencing S100A14 expression in OSCC-derived cells. External transcriptomic datasets were used to validate association between S100A14 and differentiation markers in OSCC. RESULT: Loss of S100A14 expression at the invading tumor fronts significantly correlated with poor differentiation and reduced 10-years survival of OSCC-patients. Multivariate Cox analysis identified S100A14 to be an independent prognostic factor. Modulation of S100A14 expression in OSCC-derived cells positively correlated with the expression of differentiation markers. Analysis of external datasets supported the pro-differentiation function of S100A14. CONCLUSION: These results indicate that S100A14 is a pro-differentiation protein and its expression might be useful as a prognostic marker in OSCC.

Characteristics and prognosis of primary treatment-naïve oral cavity squamous cell carcinoma in Norway, a descriptive retrospective study.

OBJECTIVES: Incidence of oral cavity squamous cell carcinomas is rising worldwide, and population characterization is important to follow for future trends. The aim of this retrospective study was to present a large cohort of primary oral cavity squamous cell carcinoma from all four health regions of Norway, with descriptive clinicopathological characteristics and five-year survival outcomes. MATERIALS AND METHODS: Patients diagnosed with primary treatment-naïve oral cavity squamous cell carcinomas at all four university hospitals in Norway between 2005-2009 were retrospectively included in this study. Clinicopathological data from the electronic health records were compared to survival data. RESULTS: A total of 535 patients with primary treatment-naïve oral cavity squamous cell carcinomas were identified. The median survival follow-up time was 48 months (range 0-125 months) after treatment. The median five-year overall survival was found to be 47%. Median five-year disease-specific survival was 52%, ranging from 80% for stage I to 33% for stage IV patients. For patients given treatment with curative intent, the overall survival was found to be 56% and disease-specific survival 62%. Median age at diagnosis was 67 years (range 24-101 years), 64 years for men and 72 years for women. The male: female ratio was 1.2. No gender difference was found in neither tumor status (p = 0.180) nor node status (p = 0.266), but both factors influenced significantly on survival (p<0.001 for both). CONCLUSIONS: We present a large cohort of primary treatment-naïve oral cavity squamous cell carcinomas in Norway. Five-year disease-specific survival was 52%, and patients eligible for curative treatment had a five-year disease-specific survival up to 62%.

Grading of oral squamous cell carcinomas - Intra and interrater agreeability: Simpler is better?

BACKGROUND: Numerous studies have been presented on histological grading of oral squamous cell carcinomas (OSCC) for predicting survival, but uncertainty of their usefulness rises due to discordances of results. A scoring system should be robust and well validated, and intra- and interrater agreement can be used as a tool to visualize the strength of reproducibility. METHODS: Here, we present an intra- and inter-observer study on evaluation of OSCC using some of the most common histopathological parameters. The observers were from different Norwegian university hospitals, and calibration to ensure accuracy was first performed. Percentage of the agreement was calculated for the score made by the individual observer at different times, as well as between pairs of observers. RESULTS: The evaluation made by the same observer at two different time points (intrarater) correlated better than observations made by different participants (interrater). In an attempt to increase the rate of agreement, many of the parameters were either dichotomized into simply low- and high grade, or to a three-tier system when more than three options in the original design. This increased the concurrence with 15.4% for the intrarater and with 23% for the interrater comparisons. CONCLUSION: High agreement for histopathological parameters can be difficult to obtain on hematoxylin and eosin staining in scoring systems with many options. A simpler system might be more advantageous to achieve higher degree of reproducibility.

Presence of high-endothelial venules correlates with a favorable immune microenvironment in oral squamous cell carcinoma.

Oral squamous cell carcinomas are associated with a poor prognosis, which may be partly due to functional impairment of the immune response. Lymphocyte recruitment to the tumor site is facilitated by high-endothelial venules, whereas expression of programmed-death ligand 1 (PD-L1) can impair T-cell function. Thus, we hypothesize that these factors are important in shaping the immune response in oral squamous cell carcinoma. In the present study, we characterized the immune infiltrate in formalin-fixed, paraffin-embedded tumor samples from 75 oral squamous cell carcinoma patients. We used immunohistochemistry to determine the distribution of immune cell subsets, high-endothelial venules, and PD-L1, as well as quantitative real-time polymerase chain reaction to assess the expression of inflammatory cytokines and chemokines associated with lymphocyte trafficking. Finally, we calculated correlations between the presence of immune cell subsets, the gene expression patterns, high-endothelial venules, PD-L1, and the clinicopathological parameters, including patient survival. The presence of high-endothelial venules correlated with increased number of CD3+ T cells and CD20+ B cells, higher levels of the chemokines CXCL12 and CCL21, and lower levels of CCL20, irrespective of the tumors' T stage. In univariate analysis, high levels of CD20+ B cells and CD68+ macrophages, positive high-endothelial venule status, and low T and N stages predicted longer patient survival. However, only the presence of high-endothelial venules and a low T stage were independent positive prognosticators. This indicates that high-endothelial venules are important mediators and a convenient marker of an antitumor immune response in oral squamous cell carcinoma. Our findings suggest that these vessels are a potential immunomodulatory target in this type of cancer. PD-L1 staining in tumor cells correlated with lower T stage, increased infiltration of CD4+ cells, and higher expression of several inflammation-related cytokines. Thus, oral squamous cell carcinomas rich in CD4+ cells may preferentially respond to PD-1/PD-L1 blockade therapy.

Cleavage of the urokinase receptor (uPAR) on oral cancer cells: regulation by transforming growth factor - ß1 (TGF-ß1) and potential effects on migration and invasion.

BACKGROUND: Urokinase plasminogen activator (uPA) receptor (uPAR) is up-regulated at the invasive tumour front of human oral squamous cell carcinoma (OSCC), indicating a role for uPAR in tumour progression. We previously observed elevated expression of uPAR at the tumour-stroma interface in a mouse model for OSCC, which was associated with increased proteolytic activity. The tumour microenvironment regulated uPAR expression, as well as its glycosylation and cleavage. Both full-length- and cleaved uPAR (uPAR (II-III)) are involved in highly regulated processes such as cell signalling, proliferation, migration, stem cell mobilization and invasion. The aim of the current study was to analyse tumour associated factors and their effect on uPAR cleavage, and the potential implications for cell proliferation, migration and invasion. METHODS: Mouse uPAR was stably overexpressed in the mouse OSCC cell line AT84. The ratio of full-length versus cleaved uPAR as analysed by Western blotting and its regulation was assessed by addition of different protease inhibitors and transforming growth factor - ß1 (TGF-ß1). The role of uPAR cleavage in cell proliferation and migration was analysed using real-time cell analysis and invasion was assessed using the myoma invasion model. RESULTS: We found that when uPAR was overexpressed a proportion of the receptor was cleaved, thus the cells presented both full-length uPAR and uPAR (II-III). Cleavage was mainly performed by serine proteases and urokinase plasminogen activator (uPA) in particular. When the OSCC cells were stimulated with TGF-ß1, the production of the uPA inhibitor PAI-1 was increased, resulting in a reduction of uPAR cleavage. By inhibiting cleavage of uPAR, cell migration was reduced, and by inhibiting uPA activity, invasion was reduced. We could also show that medium containing soluble uPAR (suPAR), and cleaved soluble uPAR (suPAR (II-III)), induced migration in OSCC cells with low endogenous levels of uPAR. CONCLUSIONS: These results show that soluble factors in the tumour microenvironment, such as TGF-ß1, PAI-1 and uPA, can influence the ratio of full length and uPAR (II-III) and thereby potentially effect cell migration and invasion. Resolving how uPAR cleavage is controlled is therefore vital for understanding how OSCC progresses and potentially provides new targets for therapy.

Presence of tumour high-endothelial venules is an independent positive prognostic factor and stratifies patients with advanced-stage oral squamous cell carcinoma.

Staging of oral squamous cell carcinoma is based on the tumour-node-metastasis (TNM) system, which has been deemed insufficient for prognostic purposes. Hence, better prognostic tools are needed to reflect the biological diversity of these cancers. Previously, high numbers of specialized blood vessels called high-endothelial venules have been reported to be associated with prolonged survival in patients with breast cancer. In this study, we analysed the prognostic value and morphological characteristics of tumour-associated high-endothelial venules in oral cancer. The presence of tumour-associated high-endothelial venules was evaluated by immunohistochemistry in 75 patients with oral squamous cell carcinoma and analysed with correlation to clinicopathological parameters, patients' survival and vessel morphology. Ten of the samples were analysed at multiple levels to evaluate intratumoural heterogeneity. The presence of tumour-associated high-endothelial venules was found to be associated with lower disease-specific death in multivariate regression analyses (P = 0.002). High-endothelial venules were present in all (n = 53) T1-T2 tumours, but only in two thirds (n = 14) of the T3-T4 tumours. The morphology of high-endothelial venules was heterogeneous and correlated with lymphocyte density. High-endothelial venules were found to be distributed homogeneously within the tumours. We found the presence of tumour-associated high-endothelial venules to be an easy-to-use, robust, and independent positive prognostic factor for patients with oral cancer. Absence of these vessels in advanced-stage tumours might identify patients with more aggressive disease. Evaluating the presence of tumour-associated high-endothelial venules might help to tailor the treatment of oral cancer patients to their individual needs.

Plectin as a prognostic marker in non-metastatic oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is associated with a poor 5-year survival rate. In general, patients diagnosed with small tumors have a fairly good prognosis, but some small tumors have an aggressive behavior leading to early death. There are at present no reliable prognostic biomarkers for oral cancers. Thus, to optimize treatment for the individual patient, there is a need for biomarkers that can predict tumor behavior. METHOD: In the present study the potential prognostic value of plectin was evaluated by a tissue microarray (TMA) based immunohistochemical analysis of primary tumor tissue obtained from a North Norwegian cohort of 115 patients diagnosed with OSCC. The expression of plectin was compared with clinicopathological variables and 5 year survival. RESULTS: The statistical analysis revealed that low expression of plectin in the tumor cells predicted a favorable outcome for patients with non-metastatic disease (p = 0.008). Furthermore, the expression of plectin was found to correlate (p = 0.01) with the expression of uPAR, which we have previously found to be a potential prognostic marker for T1N0 tumors. CONCLUSIONS: Our results indicate that low expression of plectin predicts a favorable outcome for patients with non-metastatic OSCC and the expression level of plectin may therefore be used in the treatment stratification for patients with early stage disease.

Macrophages modulate migration and invasion of human tongue squamous cell carcinoma.

Oral tongue squamous cell carcinoma (OTSCC) has a high mortality rate and the incidence is rising worldwide. Despite advances in treatment, the disease lacks specific prognostic markers and treatment modality. The spreading of OTSCC is dependent on the tumor microenvironment and involves tumor-associated macrophages (TAMs). Although the presence of TAMs is associated with poor prognosis in OTSCC, the specific mechanisms underlying this are still unknown. The aim here was to investigate the effect of macrophages (Mfs) on HSC-3 tongue carcinoma cells and NF-kappaB activity. We polarized THP-1 cells to M1 (inflammatory), M2 (TAM-like) and R848 (imidazoquinoline-treated) type Mfs. We then investigated the effect of Mfs on HSC-3 cell migration and NF-kappaB activity, cytokine production and invasion using several different in vitro migration models, a human 3D tissue invasion model, antibody arrays, confocal microscopy, immunohistochemistry and a mouse invasion model. We found that in co-culture studies all types of Mfs fused with HSC-3 cells, a process which was partially due to efferocytosis. HSC-3 cells induced expression of epidermal growth factor and transforming growth factor-beta in co-cultures with M2 Mfs. Direct cell-cell contact between M2 Mfs and HSC-3 cells induced migration and invasion of HSC-3 cells while M1 Mfs reduced HSC-3 cell invasion. M2 Mfs had an excess of NF-kappaB p50 subunit and a lack of p65 subunits both in the presence and absence of HSC-3 cells, indicating dysregulation and pro-tumorigenic NF-kappaB activation. TAM-like cells were abundantly present in close vicinity to carcinoma cells in OTSCC patient samples. We conclude that M2 Mfs/TAMs have an important role in OTSCC regulating adhesion, migration, invasion and cytokine production of carcinoma cells favouring tumor growth. These results demonstrate that OTSCC patients could benefit from therapies targeting TAMs, polarizing TAM-like M2 Mfs to inflammatory macrophages and modulating NF-kappaB activity.

Intracellular MMP-2 activity in skeletal muscle is associated with type II fibers.

Matrix metalloproteinase 2 (MMP-2) is a proteolytic enzyme implicated in motility, differentiation, and regeneration of skeletal muscle fibers through processing of extracellular substrates. Although MMP-2 has been found to be localized intracellularly in cardiomyocytes where the enzyme is thought to contribute to post-ischemic loss of contractility, little is known about intracellular MMP-2 activity in skeletal muscle fibers. In the present study we demonstrate intracellular MMP-2 in normal skeletal muscle by immunohistochemical staining. Immunogold electron microscopic analyses indicated that the enzyme was concentrated in Z-lines of the sarcomers, in the nuclear membrane, and in mitochondria. By use of in situ zymography, we found that gelatinolytic activity in muscle fibers was co-localized with immunofluorecent staining for MMP-2. Staining for MMP-9, the other member of the gelatinase group of the MMPs, was negative. The broad-spectrum metalloprotease inhibitor EDTA and the selective gelatinase inhibitor CTT2, but not the cysteine inhibitor E64, strongly reduced the gelatinolytic activity. The intracellular gelatinolytic activity was much more prominent in fast twitch type II fibers than in slow twitch type I fibers, and there was a decrease in intracellular gelatinolytic activity and MMP-2 expression in muscles from mice exposed to high intensity interval training. Together our results indicate that MMP-2 is part of the intracellular proteolytic network in normal skeletal muscle, especially in fast twitch type II fibers. Further, the results suggest that intracellular MMP-2 in skeletal muscle fibers is active during normal homeostasis, and affected by the level of physical activity.

Characterisation and prognostic value of tertiary lymphoid structures in oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinomas are often heavily infiltrated by immune cells. The organization of B-cells, follicular dendritic cells, T-cells and high-endothelial venules into structures termed tertiary lymphoid structures have been detected in various types of cancer, where their presence is found to predict favourable outcome. The purpose of the present study was to evaluate the incidence of tertiary lymphoid structures in oral squamous cell carcinomas, and if present, analyse whether they were associated with clinical outcome. METHODS: Tumour samples from 80 patients with oral squamous cell carcinoma were immunohistochemically stained for B-cells, follicular dendritic cells, T-cells, germinal centre B-cells and high-endothelial venules. Some samples were sectioned at multiple levels to assess whether the presence of tertiary lymphoid structures varied within the tumour. RESULTS: Tumour-associated tertiary lymphoid structures were detected in 21 % of the tumours and were associated with lower disease-specific death. The presence of tertiary lymphoid structures varied within different levels of a tissue block. CONCLUSIONS: Tertiary lymphoid structure formation was found to be a positive prognostic factor for patients with oral squamous cell carcinoma. Increased knowledge about tertiary lymphoid structure formation in oral squamous cell carcinoma might help to develop and guide immune-modulatory cancer treatments.

Tumour microenvironments induce expression of urokinase plasminogen activator receptor (uPAR) and concomitant activation of gelatinolytic enzymes.

BACKGROUND: The urokinase plasminogen activator receptor (uPAR) is associated with poor prognosis in oral squamous cell carcinoma (OSCC), and increased expression of uPAR is often found at the invasive tumour front. The aim of the current study was to elucidate the role of uPAR in invasion and metastasis of OSCC, and the effects of various tumour microenvironments in these processes. Furthermore, we wanted to study whether the cells' expression level of uPAR affected the activity of gelatinolytic enzymes. METHODS: The Plaur gene was both overexpressed and knocked-down in the murine OSCC cell line AT84. Tongue and skin tumours were established in syngeneic mice, and cells were also studied in an ex vivo leiomyoma invasion model. Soluble factors derived from leiomyoma tissue, as well as purified extracellular matrix (ECM) proteins, were assessed for their ability to affect uPAR expression, glycosylation and cleavage. Activity of gelatinolytic enzymes in the tissues were assessed by in situ zymography. RESULTS: We found that increased levels of uPAR did not induce tumour invasion or metastasis. However, cells expressing low endogenous levels of uPAR in vitro up-regulated uPAR expression both in tongue, skin and leiomyoma tissue. Various ECM proteins had no effect on uPAR expression, while soluble factors originating from the leiomyoma tissue increased both the expression and glycosylation of uPAR, and possibly also affected the proteolytic processing of uPAR. Tumours with high levels of uPAR, as well as cells invading leiomyoma tissue with up-regulated uPAR expression, all displayed enhanced activity of gelatinolytic enzymes. CONCLUSIONS: Although high levels of uPAR are not sufficient to induce invasion and metastasis, the activity of gelatinolytic enzymes was increased. Furthermore, several tumour microenvironments have the capacity to induce up-regulation of uPAR expression, and soluble factors in the tumour microenvironment may have an important role in the regulation of posttranslational modification of uPAR.

Clinicopathological characteristics of oral squamous cell carcinoma in Northern Norway: a retrospective study.

BACKGROUND: The main aim of the study was to evaluate if patients with oral squamous carcinomas in Northern Norway differ from patients in other countries with regard to clinicopathological characteristics and also study the influence of risk factors. Such a comparison is of demographical interest, and also important for the interpretation of result from studies on prognostic biomarkers. METHODS: We describe clinicopathological characteristics of 133 North Norwegian patients diagnosed with squamous cell carcinoma of the oral cavity in the period 1986-2002, and evaluate the significance of different risk factors. RESULTS: The cohort consisted of 69 men and 64 women, giving male/female ratio of 1.1. Forty-seven of the 133 patients (35%) died of the disease within 5 years from diagnosis. There was no significant difference between the genders concerning time to disease specific death, even though men both smoked and drank more alcohol than women. As expected, the strongest predictors for disease specific death were tumour size and the presence of regional lymph node metastasis. We also found that heavy smokers and drinkers presented with more advanced disease, more often localized to the floor of mouth compared to non-smoking and abstinent patients, who more often presented with tumours of the mobile tongue. CONCLUSIONS: Our results correlate well with previously published clinicopathological data on comparable cohorts, which is important when considering the applicability of results from biomarker studies performed on this material compared to other cohorts, and vice versa.

Urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) are potential predictive biomarkers in early stage oral squamous cell carcinomas (OSCC).

Oral squamous cell carcinoma (OSCC) is often associated with metastatic disease and a poor 5 year survival rate. Patients diagnosed with small tumours generally have a more favourable outcome, but some of these small tumours are aggressive and lead to early death. To avoid harmful overtreatment of patients with favourable prognosis, there is a need for predictive biomarkers that can be used for treatment stratification. In this study we assessed the possibility to use components of the plasminogen activator (PA) system as prognostic markers for OSCC outcome and compared this to the commonly used biomarker Ki-67. A tissue-micro-array (TMA) based immunohistochemical analysis of primary tumour tissue obtained from a North Norwegian cohort of 115 patients diagnosed with OSCC was conducted. The expression of the biomarkers was compared with clinicopathological variables and disease specific death. The statistical analyses revealed that low expression of uPAR (p = 0.031) and PAI-1 (p = 0.021) in the tumour cells was significantly associated with low disease specific death in patients with small tumours and no lymph node metastasis (T1N0). The commonly used biomarker, Ki-67, was not associated with disease specific death in any of the groups of patients analysed. The conclusion is that uPAR and PAI-1 are potential predictive biomarkers in early stage tumours and that this warrants further studies on a larger cohort of patients.

Matrix metalloproteinases in cancer: their value as diagnostic and prognostic markers and therapeutic targets.

Biomarkers are used as tools in cancer diagnostics and in treatment stratification. In most cancers, there are increased levels of one or several members of the matrix metalloproteinases (MMPs). This is a family of proteolytic enzymes that are involved in many phases of cancer progression, including angiogenesis, invasiveness, and metastasis. It has therefore been expected that MMPs could serve as both diagnostic and prognostic markers in cancer patients, but despite a huge number of studies, it has been difficult to establish MMPs as cancer biomarkers. In the present paper, we assess some of the challenges associated with MMP research as well as putative reasons for the conflicting data on the value of these enzymes as diagnostic and prognostic markers in cancer patients. We also review the prognostic value of a number of MMPs in patients with lung, colorectal, breast, and prostate cancers. The review also discusses MMPs as potential target molecules for therapeutic agents and new strategies for development of such drugs.

In vitro reconstitution of complexes between pro-matrix metalloproteinase-9 and the proteoglycans serglycin and versican.

Previously, we have shown that a proportion of the matrix metalloproteinase-9 (MMP-9) synthesized by the macrophage cell line THP-1 binds to a chondroitin sulfate proteoglycan (CSPG) core protein to form a reduction-sensitive heteromer. It was also shown that the hemopexin-like (PEX) domain and the fibronectin-like (FnII) module in the enzyme are involved in heteromer formation. In this paper, we show that reduction-sensitive and SDS-stable heteromers may be reconstituted in vitro by mixing proMMP-9 with either serglycin, versican or CSPGs isolated from various monocytic cell lines. In addition, a strong but SDS-soluble proMMP-9·CSPG heteromer was formed. The two macromolecules in the SDS-stable reduction-sensitive heteromers were not linked together by disulfide bonds. As for the heteromer isolated from THP-1 cells, in vitro reconstituted SDS-stable and SDS-soluble heteromers showed weaker binding to gelatin than the proMMP-9 monomer. Furthermore, gelatin inhibited in vitro reconstitution of the heteromers, showing that the FnII module is involved in the complex formation. Tissue inhibitor of metalloproteinase (TIMP)-1 was not be detected in the proMMP-9·CSPG complexes. However, the presence of TIMP-1 inhibited formation of the SDS-soluble heteromer, but not the SDS-stable reduction-sensitive heteromer. This indicates that different regions in the PEX domain are involved formation of these heteromers.

Tissue- and cell-specific co-localization of intracellular gelatinolytic activity and matrix metalloproteinase 2.

Matrix metalloproteinase 2 (MMP-2) is a proteolytic enzyme that degrades extracellular matrix proteins. Recent studies indicate that MMP-2 also has a role in intracellular proteolysis during various pathological conditions, such as ischemic injuries in heart and brain and in tumor growth. The present study was performed to map the distribution of intracellular MMP-2 activity in various mouse tissues and cells under physiological conditions. Samples from normal brain, heart, lung, liver, spleen, pancreas, kidney, adrenal gland, thyroid gland, gonads, oral mucosa, salivary glands, esophagus, intestines, and skin were subjected to high-resolution in situ gelatin zymography and immunohistochemical staining. In hepatocytes, cardiac myocytes, kidney tubuli cells, epithelial cells in the oral mucosa as well as in excretory ducts of salivary glands, and adrenal cortical cells, we found strong intracellular gelatinolytic activity that was significantly reduced by the metalloprotease inhibitor EDTA but not by the cysteine protease inhibitor E-64. Furthermore, the gelatinolytic activity was co-localized with MMP-2. Western blotting and electron microscopy combined with immunogold labeling revealed the presence of MMP-2 in different intracellular compartments of isolated hepatocytes. Our results indicate that MMP-2 takes part in intracellular proteolysis in specific tissues and cells during physiological conditions.