Relationship between matrix metalloproteinase-2 mRNA expression and clinicopathological and urokinase-type plasminogen activator system parameters and prognosis in human gastric cancer

Signaling pathways of oxidative stress response: the potential therapeutic targets in gastric cancer

Gastric cancer is one of the top causes of cancer-related death globally. Although novel treatment strategies have been developed, attempts to eradicate gastric cancer have been proven insufficient. Oxidative stress is continually produced and continually present in the human body. Increasing evidences show that oxidative stress contributes significantly to the development of gastric cancer, either through initiation, promotion, and progression of cancer cells or causing cell death. As a result, the purpose of this article is to review the role of oxidative stress response and the subsequent signaling pathways as well as potential oxidative stress-related therapeutic targets in gastric cancer. Understanding the pathophysiology of gastric cancer and developing new therapies for gastric cancer depends on more researches focusing on the potential contributors to oxidative stress and gastric carcinogenesis.

Experimental and Clinical Evidence Supports the Use of Urokinase Plasminogen Activation System Components as Clinically Relevant Biomarkers in Gastroesophageal Adenocarcinoma

Simple Summary

Patients with gastric and oesophageal adenocarcinomas (GOCs) have short life expectancies as their tumours spread to other sites early. This is facilitated by the increased expression of the urokinase plasminogen activation system (uPAS); a feature of the majority of GOCs. There is increasing appreciation of the importance of uPAS expression in a range of cell types within the tumour microenvironment. Abundant clinical evidence indicates that altered expression of uPAS proteins is associated with worse outcomes, including time to tumour recurrence and patient survival. Emerging technologies, including liquid biopsy, suggest a role of uPAS for the detection of circulating tumour cells, which are responsible for the dissemination of cancers. We review and summarise pre-clinical and clinical data that supports the use of uPAS as a biomarker in GOC.

Abstract

Gastric and oesophageal cancers (GOCs) are lethal cancers which metastasise early and recur frequently, even after definitive surgery. The urokinase plasminogen activator system (uPAS) is strongly implicated in the invasion and metastasis of many aggressive tumours including GOCs. Urokinase plasminogen activator (uPA) interaction with its receptor, urokinase plasminogen activator receptor (uPAR), leads to proteolytic activation of plasminogen to plasmin, a broad-spectrum protease which enables tumour cell invasion and dissemination to distant sites. uPA, uPAR and the plasminogen activator inhibitor type 1 (PAI-1) are overexpressed in some GOCs. Accumulating evidence points to a causal role of activated receptor tyrosine kinase pathways enhancing uPAS expression in GOCs. Expression of these components are associated with poorer clinicopathological features and patient survival. Stromal cells, including tumour-associated macrophages and myofibroblasts, also express the key uPAS proteins, supporting the argument of stromal involvement in GOC progression and adverse effect on patient survival. uPAS proteins can be detected on circulating leucocytes, circulating tumour cells and within the serum; all have the potential to be developed into circulating biomarkers of GOC. Herein, we review the experimental and clinical evidence supporting uPAS expression as clinical biomarker in GOC, with the goal of developing targeted therapeutics against the uPAS.

Ab locks for improving the selectivity and safety of antibody drugs

Monoclonal antibodies (mAbs) are a major targeted therapy for malignancies, infectious diseases, autoimmune diseases, transplant rejection and chronic inflammatory diseases due to their antigen specificity and longer half-life than conventional drugs. However, long-term systemic antigen neutralization by mAbs may cause severe adverse events. Improving the selectivity of mAbs to distinguish target antigens at the disease site from normal healthy tissue and reducing severe adverse events caused by the mechanisms-of-action of mAbs is still a pressing need. Development of pro-antibodies (pro-Abs) by installing a protease-cleavable Ab lock is a novel and advanced recombinant Ab-based strategy that efficiently masks the antigen binding ability of mAbs in the normal state and selectively "turns on" the mAb activity when the pro-Ab reaches the proteolytic protease-overexpressed diseased tissue. In this review, we discuss the design and advantages/disadvantages of different Ab lock strategies, focusing particularly on spatial-hindrance-based and affinity peptide-based approaches. We expect that the development of different masking strategies for mAbs will benefit the local reactivity of mAbs at the disease site, increase the therapeutic efficacy and safety of long-term treatment with mAbs in chronic diseases and even permit scientists to develop Ab drugs for formerly undruggable targets and satisfy the unmet medical needs of mAb therapy.

Components of the Plasminogen-Plasmin System as Biologic Markers for Cancer

Members of the plasminogen-plasmin (PP) system participate in many physiologic functions. In particular, uPA, its receptor (uPAR) and its inhibitor PAI-1 play an important role in cell migration, cell proliferation and tissue remodeling. Through a number of interactions, these components of the PP system are also involved in the pathogenesis of many diseases. In cancer, they modulate the essential processes of tumor development, growth, invasion and metastasis as well as angiogenesis and fibrosis. Thus, quantification of uPA, uPAR and PAI-1 in tumors and, in some cases in the circulating blood, became of potential value in the prognostication of many types of cancer. These include cancer of the breast, stomach, colon and rectum, esophagus, pancreas, glioma, lung, kidney, prostate, uterine cervix, ovary, liver and bone. Published data are reviewed in this chapter. Clinical validation of the prognostic value has also been made, particularly in cancer of the breast. Inclusion of these biomarkers in the risk assessment of cancer patients is now considered in the risk-adapted management in carcinoma of the breast. Factors limiting its broader use are discussed with suggestions how these can be overcome. Hopefully the use of these biomarkers will be applied to other types of cancer in the near future.

Involvement of urokinase-type plasminogen activator system in cancer: an overview

Currently, there are several studies supporting the role of urokinase-type plasminogen activator (uPA) system in cancer. The association of uPA to its receptor triggers the conversion of plasminogen into plasmin. This process is regulated by the uPA inhibitors (PAI-1 and PAI-2). Plasmin promotes degradation of basement membrane and extracellular matrix (ECM) components as well as activation of ECM latent matrix metalloproteases. Degradation and remodeling of the surrounding tissues is crucial in the early steps of tumor progression by facilitating expansion of the tumor mass, release of tumor growth factors, activation of cytokines as well as induction of tumor cell proliferation, migration, and invasion. Hence, many tumors showed a correlation between uPA system component levels and tumor aggressiveness and survival. Therefore, this review summarizes the structure of the uPA system, its contribution to cancer progression, and the clinical relevance of uPA family members in cancer diagnosis. In addition, the review evaluates the significance of uPA system in the development of cancer-targeted therapies.

VEGF and metalloproteinase 2 (MMP 2) expression in gastric cancer tissue

BACKGROUND

Neoplasms are the second leading cause of death in Poland after vessel diseases, despite the huge progress in medical sciences in the last 20 years. Recently, gastric cancer morbidity has decreased, but mortality is still at a high level.

MATERIAL/METHODS

Tissues from 24 patients with a histopathologically diagnosed mucosal and adenomucosal gastric cancer were tested. Patients were divided into 2 equal groups: patients without metastases (G1) and patients with metastases in the liver (G2). In all tested tissues of G1 and G2, the expression of VEGF (vascular endothelial growth factor) and metalloproteinase 2, respectively, were estimated.

RESULTS

Results revealed a statistically significant increase in the VEGF expression for G1 and G2 in relation to the margin (p1<0.001; p2<0.001). The increase of gene expression for VEGF did not significantly differ statistically in G1 and G2. The obtained results revealed a statistically significant difference in the increase of gene expression for MMP-2 in G1 in relation to the margin (p<0.05) and a very high one in G2 in relation to the average margin value (p<0.001). A highly statistically significant correlation was obtained for VEGF and MMP-2 in the tissue of patients with metastases (p<0.001; r=0.714). The highly elevated expression of MMP-2 in the tissue of gastric cancer in patients with metastases confirms its participation in the invasiveness of the neoplasmatic process.

CONCLUSIONS

The highly significant correlation between VEGF and MMP-2 suggests a connection between both mechanisms in the progression of gastric cancer.

Claudin-4 expression is associated with tumor invasion, MMP-2 and MMP-9 expression in gastric cancer

Claudin-4 is a member of the claudin family, a large family of transmembrane proteins that are essential in the formation and maintenance of tight junctions. Matrix metal-loproteinase (MMP)-2 and -9 degrade type IV collagen of the extracellular matrix and basal membranes. Claudin-4 activates MMP-2, indicating that claudin-mediated increased cancer cell invasion may result from the activation of MMP proteins. In the present study, we used immunohistochemistry to examine the expression levels of claudin-4, MMP-2 and MMP-9 in 189 gastric cancer samples, and analyzed their correlation with tumor invasion, clinicopathologic parameters and clinical outcome. The relationship between claudin-4 expression and MMP-2 and -9 expression was also investigated. The expression of claudin-4 was found to be significantly higher in gastric cancer cases with advanced depth of wall invasion, lymph node metastasis, lymphatic invasion and higher TNM stage. Further analysis revealed claudin-4 expression to be significantly correlated with the expression of MMP-2 and -9. Kaplan-Meier survival analysis indicated that MMP-9 expression was correlated with poor prognosis. These results suggest that claudin-4 expression is associated with tumor invasion and with MMP-2 and -9 expression in gastric cancer. Additionally, MMP-9 expression was demonstrated to serve as a prognostic factor in patients with gastric cancer.

The T-box transcription factor Brachyury promotes epithelial-mesenchymal transition in human tumor cells

Metastatic disease is responsible for the majority of human cancer deaths. Understanding the molecular mechanisms of metastasis is a major step in designing effective cancer therapeutics. Here we show that the T-box transcription factor Brachyury induces in tumor cells epithelial-mesenchymal transition (EMT), an important step in the progression of primary tumors toward metastasis. Overexpression of Brachyury in human carcinoma cells induced changes characteristic of EMT, including upregulation of mesenchymal markers, downregulation of epithelial markers, and an increase in cell migration and invasion. Brachyury overexpression also repressed E-cadherin transcription, an effect partially mediated by Slug. Conversely, inhibition of Brachyury resulted in downregulation of mesenchymal markers and loss of cell migration and invasion and diminished the ability of human tumor cells to form lung metastases in a xenograft model. Furthermore, we found Brachyury to be overexpressed in various human tumor tissues and tumor cell lines compared with normal tissues. We also determined that the percentage of human lung tumor tissues positive for Brachyury expression increased with the stage of the tumor, indicating a potential association between Brachyury and tumor progression. The selective expression of Brachyury in tumor cells and its role in EMT and cancer progression suggest that Brachyury may be an attractive target for antitumor therapies.

The footprints of cancer development: Cancer biomarkers

Diagnostic detection and measurement of cancer disease progression are essential elements for successful cancer disease management. The early stages of cancer development carry the maximum potential for therapeutic interventions. However, these stages are often asymptomatic, leading to delayed diagnosis at the very advanced stages when effective treatments are unavailing. The application of biomarkers to cancer is leading the way because of the unique association of genomic changes in cancer cells with the disease process. They have the potential to not only help identify who will develop cancer but also to predict as to when the event is most likely to occur. In recent years, there has been an enormous effort to develop specific and sensitive biomarkers for precise and accurate screening, diagnosis, prognosis and monitoring of high risk cancer to assist with therapeutic decisions. The present article is a brief review of the emerging trends in the development of biomarkers for early detection and precise evaluation of cancer disease.

Changes of histology and expression of MMP-2 and nm23-H1 in primary and metastatic gastric cancer

AIM: To investigate the changes of histology and expression of MMP-2 and nm23-H1 in primary and metastatic gastric cancer.

METHODS: One hundred and seventy-seven gastric cancer patients with lymph node and/or distal metastasis between 1997 and 2001 were reviewed. Differences in histology of the primary and metastatic gastric cancer were assessed. MMP-2 and nm23-H1 immunoreactivity was compared in 44 patients with tumor infiltration to the serosa layer.

RESULTS: Poorly and moderately differentiated metastatic gastric cancer was found in 88.7% (157/177) and primary gastric cancer in 75.7% (134/177) of the patients. The histological type of metastatic gastric cancer that was not completely in accordance with the preponderant histology of primary gastric cancer was observed in 25 patients (14.1%). MMP-2 immunoreactivity in metastatic gastric cancer was significantly stronger than that in primary gastric cancer, while nm23-H1 immunoreactivity showed no difference in primary and metastatic gastric cancer.

CONCLUSION: Metastatic gastric cancer presents more aggressive histological morphology and higher MMP-2 immunoreactivity than primary gastric cancer. This heterogeneity may elicit a possible mechanism of gastric cancer metastasis.

Evolving role of uPA/uPAR system in human cancers

Recent advancements in cancer research have led to some major breakthroughs; however, the impact on overall cancer-related death rate remains unacceptable, suggesting that further insight into tumor markers and development of targeted therapies is urgently needed. The urokinase plasminogen activator (uPA) system represents a family of serine proteases that are involved in the degradation of basement membrane and the extracellular matrix, leading to tumor cell invasion and metastasis. In this review, we have provided an overview of emerging data, from basic research as well as clinical studies, highlighting the evolving role of uPA/uPAR system in tumor progression. It is currently believed that the expression and activation of uPA plays an important role in tumorigenicity, and high endogenous levels of uPA and uPAR are associated with advanced metastatic cancers. The endogenous inhibitors of this system, PAI-1 and PAI-2, regulate uPA-uPAR activity by either direct inhibition or affecting cell surface expression and internalization. PAI-1's role in cancers is rather unusual; on one hand, it inhibits uPA-uPAR leading to inhibition of invasion and metastasis and on the other it has been reported to facilitate tumor growth and angiogenesis. Individual components of uPA/uPAR system are reported to be differentially expressed in cancer tissues compared to normal tissues and, thus, have the potential to be developed as prognostic and/or therapeutic targets. Therefore, this system represents a highly attractive target that warrants further in-depth studies. Such studies are likely to contribute towards the development of molecularly-driven targeted therapies in the near future.

Clinicopathological significance of MMP-2 and TIMP-2 genotypes in gastric cancer

AIMS

Single nucleotide polymorphisms in matrix metalloproteinase-2 (MMP-2) -1306 C/T and tissue inhibitor of metalloproteinase-2 (TIMP-2) -418 G/C abolish the Sp-1 binding site and down-regulate expression of these genes. We aim to elucidate the role of MMP-2 and TIMP-2 in clinicopathological manifestations of gastric cancer.

METHODS

We enrolled 240 gastric cancer patients and 283 controls. DNA was extracted from peripheral blood leucocytes. MMP-2 and TIMP-2 genotypes were analysed by PCR-direct sequencing and PCR-RFLP method, respectively.

RESULTS

MMP-2 and TIMP-2 genotypes were not associated with gastric cancer development. However, patients with MMP-2 -1306 C/C genotype showed higher risk of lymphatic invasion (odds ratio (OR)=2.77, p=0.01) and venous invasion (OR=2.93, p=0.012). TIMP-2 G/G genotype was associated with serosal invasion (OR=1.89, p=0.009), lymph node metastasis (OR=2.19, p=0.021), lymphatic invasion (OR=2.87, p=0.016) and venous invasion (OR=2.65, p=0.033).

CONCLUSION

Our results suggest MMP-2 and TIMP-2 genotypes play a crucial role in gastric cancer invasion, but not with development of gastric cancer.

Matrix metalloproteinase-2 is a consistent prognostic factor in gastric cancer

In a pioneer study, we showed 10 years ago that enhanced tissue levels of the matrix metalloproteinases (MMPs) MMP-2 and MMP-9 in gastric cancers, as determined by zymography, were related with worse overall survival of the patients. To corroborate these observations, we now assessed MMP-2 and MMP-9 with new techniques in an expanded group of gastric cancer patients (n=81) and included for comparison MMP-7, MMP-8 and the tissue inhibitors of MMPs, TIMP-1 and -2. All MMPs and TIMP-1 were significantly increased in tumour tissue compared to normal gastric mucosa. Matrix metalloproteinase-7, -8 and -9, and the TIMPs showed some correlations with the clinicopathologic parameters TNM, WHO and Laurén classification, but their levels were not related with survival. Regardless of the determination method used, that is, enzyme-linked immunosorbent assay or bioactivity assay, an enhanced tumour MMP-2 level did not show a significant correlation with any of the clinicopathological parameters, but was confirmed to be an independent prognostic factor in gastric cancer.