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

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.

Tissue plasminogen activator is a ligand of cation-independent mannose 6-phosphate receptor and consists of glycoforms that contain mannose 6-phosphate

Plasmin is the key enzyme in fibrinolysis. Upon interaction with plasminogen activators, the zymogen plasminogen is converted to active plasmin. Some studies indicate plasminogen activation is regulated by cation-independent mannose 6-phosphate receptor (CI-MPR), a protein that facilitates lysosomal enzyme trafficking and insulin-like growth factor 2 downregulation. Plasminogen regulation may be accomplished by CI-MPR binding to plasminogen or urokinase plasminogen activator receptor. We asked whether other members of the plasminogen activation system, such as tissue plasminogen activator (tPA), also interact with CI-MPR. Because tPA is a glycoprotein with three N-linked glycosylation sites, we hypothesized that tPA contains mannose 6-phosphate (M6P) and binds CI-MPR in a M6P-dependent manner. Using surface plasmon resonance, we found that two sources of tPA bound the extracellular region of human and bovine CI-MPR with low-mid nanomolar affinities. Binding was partially inhibited with phosphatase treatment or M6P. Subsequent studies revealed that the five N-terminal domains of CI-MPR were sufficient for tPA binding, and this interaction was also partially mediated by M6P. The three glycosylation sites of tPA were analyzed by mass spectrometry, and glycoforms containing M6P and M6P-N-acetylglucosamine were identified at position N448 of tPA. In summary, we found that tPA contains M6P and is a CI-MPR ligand.

Plasmin and Plasminogen System in the Tumor Microenvironment: Implications for Cancer Diagnosis, Prognosis, and Therapy

The tumor microenvironment (TME) is now being widely accepted as the key contributor to a range of processes involved in cancer progression from tumor growth to metastasis and chemoresistance. The extracellular matrix (ECM) and the proteases that mediate the remodeling of the ECM form an integral part of the TME. Plasmin is a broad-spectrum, highly potent, serine protease whose activation from its precursor plasminogen is tightly regulated by the activators (uPA, uPAR, and tPA), the inhibitors (PAI-1, PAI-2), and plasminogen receptors. Collectively, this system is called the plasminogen activation system. The expression of the components of the plasminogen activation system by malignant cells and the surrounding stromal cells modulates the TME resulting in sustained cancer progression signals. In this review, we provide a detailed discussion of the roles of plasminogen activation system in tumor growth, invasion, metastasis, and chemoresistance with specific emphasis on their role in the TME. We particularly review the recent highlights of the plasminogen receptor S100A10 (p11), which is a pivotal component of the plasminogen activation system.

The Role of the Plasminogen Activation System in Angioedema: Novel Insights on the Pathogenesis

The main physiological functions of plasmin, the active form of its proenzyme plasminogen, are blood clot fibrinolysis and restoration of normal blood flow. The plasminogen activation (PA) system includes urokinase-type plasminogen activator (uPA), tissue-type PA (tPA), and two types of plasminogen activator inhibitors (PAI-1 and PAI-2). In addition to the regulation of fibrinolysis, the PA system plays an important role in other biological processes, which include degradation of extracellular matrix such as embryogenesis, cell migration, tissue remodeling, wound healing, angiogenesis, inflammation, and immune response. Recently, the link between PA system and angioedema has been a subject of scientific debate. Angioedema is defined as localized and self-limiting edema of subcutaneous and submucosal tissues, mediated by bradykinin and mast cell mediators. Different forms of angioedema are linked to uncontrolled activation of coagulation and fibrinolysis systems. Moreover, plasmin itself can induce a potentiation of bradykinin production with consequent swelling episodes. The number of studies investigating the PA system involvement in angioedema has grown in recent years, highlighting its relevance in etiopathogenesis. In this review, we present the components and diverse functions of the PA system in physiology and its importance in angioedema pathogenesis.

Mathematical Model and Numerical Simulation for Electric Field Induced Cancer Cell Migration

A mathematical model describing the interaction of cancer cells with the urokinase plasminogen activation system is represented by a system of partial differential equations, in which cancer cell dynamics accounts for diffusion, chemotaxis, and haptotaxis contributions. The mutual relations between nerve fibers and tumors have been recently investigated, in particular, the role of nerves in the development of tumors, as well neurogenesis induced by cancer cells. Such mechanisms are mediated by neurotransmitters released by neurons as a consequence of electrical stimuli flowing along the nerves, and therefore electric fields can be present inside biological tissues, in particular, inside tumors. Considering cancer cells as negatively charged particles immersed in the correct biological environment and subjected to an external electric field, the effect of the latter on cancer cell dynamics is still unknown. Here, we implement a mathematical model that accounts for the interaction of cancer cells with the urokinase plasminogen activation system subjected to a uniform applied electric field, simulating the first stage of cancer cell dynamics in a three-dimensional axial symmetric domain. The obtained numerical results predict that cancer cells can be moved along a preferred direction by an applied electric field, suggesting new and interesting strategies in cancer therapy.

Unique transcriptional changes in coagulation cascade genes in SARS-CoV-2-infected lung epithelial cells: A potential factor in COVID-19 coagulopathies

ABSTRACTSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a global pandemic. In addition to the acute pulmonary symptoms of COVID-19 (the disease associated with SARS-CoV-2 infection), pulmonary and distal coagulopathies have caused morbidity and mortality in many patients. Currently, the molecular pathogenesis underlying COVID-19 associated coagulopathies are unknown. While there are many theories for the cause of this pathology, including hyper inflammation and excess tissue damage, the cellular and molecular underpinnings are not yet clear. By analyzing transcriptomic data sets from experimental and clinical research teams, we determined that changes in the gene expression of genes important in the extrinsic coagulation cascade in the lung epithelium may be important triggers for COVID-19 coagulopathy. This regulation of the extrinsic blood coagulation cascade is not seen with influenza A virus (IAV)-infected NHBEs suggesting that the lung epithelial derived coagulopathies are specific to SARS-Cov-2 infection. This study is the first to identify potential lung epithelial cell derived factors contributing to COVID-19 associated coagulopathy.GRAPHICAL ABSTRACTAUTHOR SUMMARYWhy was this study done?Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a global pandemic.In addition to the acute pulmonary symptoms of COVID-19 (the disease associated with SARS-CoV-2 infection), pulmonary and distal coagulopathies have caused morbidity and mortality in many patients.Currently, the molecular pathogenesis underlying COVID-19 associated coagulopathies are unknown. Understanding the molecular basis of dysregulated blood coagulation during SARS-CoV-2 infection may help promote new therapeutic strategies to mitigate these complications in COVID-19 patients.What did the researchers do and find?We analyzed three publicly available RNA sequencing datasets to identify possible molecular etiologies of COVID-19 associated coagulopathies. These data sets include sequencing libraries from clinically isolated samples of bronchoalveolar lavage fluid (BALF) and peripheral blood mononuclear cells (PBMCs) from SARS-CoV-2 positive patients and healthy controls. We also analyzed a publicly available RNA sequencing dataset derived from in vitro SARS-CoV-2 infected primary normal human bronchial epithelial (NHBE) cells and mock infected samples.Pathway analysis of both NHBE and BALF differential gene expression gene sets. We found that SARS-CoV-2 infection induces the activation of the extrinsic blood coagulation cascade and suppression of the plasminogen activation system in both NHBEs and cells isolated from the BALF. PBMCs did not differentially express genes regulating blood coagulation.Comparison with influenza A virus (IAV)-infected NHBEs revealed that the regulation of the extrinsic blood coagulation cascade is unique to SARS-CoV-2, and not seen with IAV infection.What do these findings mean?The hyper-activation of the extrinsic blood coagulation cascade and the suppression of the plasminogen activation system in SARS-CoV-2 infected epithelial cells may drive diverse coagulopathies in the lung and distal organ systems.The gene transcription pattern in SARS-CoV-2 infected epithelial cells is distinct from IAV infected epithelial cells with regards to the regulation of blood coagulation.

Influence of urokinase gene knockout on tissue levels of biogenic amines in mice with melanoma.

e22109 Background: The plasminogen activation system and biogenic amines are involved in melanoma pathogenesis, but currently, the mutual influence of the components of these systems on each other is unknown. The purpose of the study was to reveal the dynamics of biogenic amines in the brain and intact and tumorous skin (B16/F10 melanoma) in C57BL/6-PlautmI.IBug-ThisPlau6FDhu/GFDhu mice with uPA gene knockout. Methods: The study included male and female C57BL/6-PlautmI.IBug-This Plau6FDhu/GFDhu mice, n = 38; the comparison group included C57BL/6 mice without uPA gene knockout, n = 61. Melanoma was transplanted under the skin of the back. Levels of biogenic amines were measured in tissues taken in week 3 of carcinogenesis by ELISA using standard test systems (Cusabio, China). Results: The total content of biogenic amines was elevated in tissues of intact C57BL/6-PlautmI.IBug-ThisPlau6FDhu/GFDhu mice: in the skin – due to the noradrenaline (NA) rise by 4.8 times in males and by 4.9 times in females, histamine (H) – by 3.6 times in males and 1.6 times (p < 0.05) in females, serotonin (5HT) by 3.4 times in males and 8.3 times in females; in the brain – due to the NA rise by 3.5 times in males and 3.2 times in females, dophamine by 2.1 times in males and 2.9 times in females, while H levels declined. Distinctive features of the melanoma development in C57BL/6-PlautmI.IBug-ThisPlau6FDhu/GFDhu mice included: lower levels of adrenaline with high NA concentrations and an enhanced synthesis and inactivation of 5HTin the brain. The content of catecholamines in the tumor nodes was the same as in C57BL/6 mice, with a high concentration of H recorded in the tumor and skin, together with a high 5HT level in the skin. Conclusions: The uPA gene knockout limits the development of stress at the central regulatory and peripheral effector levels, and modulates the immune antitumor response by increasing serotonergic mediation in the brain and increasing serotonin and histamine levels in the skin of mice with B16/F10 melanoma.

Relationship of chronic neurogenic pain and fibrinolysis in the blood of patients with melanoma.

e22085 Background: The plasminogen regulation system is critical in triggering proteolysis to cleave the extracellular matrix and basement membrane. The “uPA-uPAR” system is involved in extravascular fibrinolysis and is responsible for the formation of plasmin associated with invasion and metastasis. The purpose of the study was to analyze levels of factors of the plasminogen regulation system in the blood of patients with cutaneous melanoma (M) and chronic neurogenic pain (CNP). Methods: Blood levels of PAP, uPA, uPAR and PAI-1 were measured by ELISA in patients with Т3-4NxM0 melanoma: 21 women with CNP (pelvic pain - 7, osteochondrosis – 14), mean age 67.2±2.7 years; 17 men with CNP (osteochondrosis), mean age 65.6±3.1 years. The control group included patients with melanoma similar in age, gender and disease stages without CNP. Results: Blood levels of PAP in women with M+CNP were twice higher than in patients with M without CNP, the levels in men with M+CNP did not change; uPA content increased in both women and men with M without CNP by 1.4 and 1.5 times, uPA activity was elevated only in women by 2.4 times, in men it was reduced by 2 times; uPAR was increased by 1.5 times in women and men compared to the values in both female and male patients with M without CNP. PAI-1 content in women and men with M+CNP was similar to control values, and its activity was increased in women by 1.5 times and decreased in men by 2.5 times. Conclusions: The study gives significant additional information on the effect of CNP on relationships in the plasminogen activation system in a combination of cutaneous melanoma and CNB showing marked gender differences. The results should be taken into account in the special treatment of patients with melanoma.

Changes in the content of some components of the plasminogen activation system in the plasma of bladder cancer patients

Bladder cancer (BC) continues to be a disease with a high mortality rate. Bladder cancer is the sixth for men and seventeenth for women in the incidence of malignancy worldwide. The invasion and metastasis of malignant tumors are caused by a sequence of processes, including loss of cell-cell and / or cell-matrix adhesion, proteolysis, and induction of angiogenesis. Different protease systems are involved in these processes, especially during the invasion and development of metastases. One such protease system is a plasminogen activation system or fibrinolysis system. Changes in the balance of plasminogen activation systems have been investigated in many types of malignancies, and these changes may not only indicate the functioning of this system but may also have prognostic significance. In malignancies, the components of this system are involved in the growth, invasion, and metastasis of tumors, affecting cell migration and angiogenesis. The main, but a well-studied component of the plasminogen activation system is serine proteinase – urokinase-type plasminogen activator (uPA). In contrast to uPA, tissue-type plasminogen activator (tPA) is characterized by a high affinity for fibrin and is involved in thrombolysis. Both types of plasminogen activators are synthesized in tumor tissues: tPA and uPA. The largest player among the inhibitors of fibrinolysis is the plasminogen activator inhibitor type 1 (PAI-1), involved in the pathogenesis of many cardiovascular diseases, as well as in cancer. The purpose of this study was to detect changes in the content of plasminogen activator tissue type tPA and PAI-1 in the blood plasma of patients with BC at different stages of the disease. The study involved 40 men who were verified with a diagnosis of BC. The content of tPA and PAI-1 in preoperative blood plasma was determined by enzyme immunoassay in ELISA modification. In our study, changes in the tPA and PAI-1 content of the blood plasma at different stages were identified, which can characterize tumor growth and invasion and can supplement existing disease information.