Tissue factor in tumour progression

The Tissue Factor Pathway in Cancer: Overview and Role of Heparan Sulfate Proteoglycans

Historically, the only focus on tissue factor (TF) in clinical pathophysiology has been on its function as the initiation of the extrinsic coagulation cascade. This obsolete vessel-wall TF dogma is now being challenged by the findings that TF circulates throughout the body as a soluble form, a cell-associated protein, and a binding microparticle. Furthermore, it has been observed that TF is expressed by various cell types, including T-lymphocytes and platelets, and that certain pathological situations, such as chronic and acute inflammatory states, and cancer, may increase its expression and activity. Transmembrane G protein-coupled protease-activated receptors can be proteolytically cleaved by the TF:FVIIa complex that develops when TF binds to Factor VII (PARs). The TF:FVIIa complex can activate integrins, receptor tyrosine kinases (RTKs), and PARs in addition to PARs. Cancer cells use these signaling pathways to promote cell division, angiogenesis, metastasis, and the maintenance of cancer stem-like cells. Proteoglycans play a crucial role in the biochemical and mechanical properties of the cellular extracellular matrix, where they control cellular behavior via interacting with transmembrane receptors. For TFPI.fXa complexes, heparan sulfate proteoglycans (HSPGs) may serve as the primary receptor for uptake and degradation. The regulation of TF expression, TF signaling mechanisms, their pathogenic effects, and their therapeutic targeting in cancer are all covered in detail here.

Small cell lung cancer: circulating tumor cell lines and expression of mediators of angiogenesis and coagulation

Aim

Coagulation is frequently activated in cancer patients and has been correlated with an unfavorable prognosis. To evaluate whether a putative release of tissue factor (TF) by circulating tumor cells (CTCs) represents a target to impair the dissemination of small cell lung cancer (SCLC), the expression of relevant proteins in a panel of permanent SCLC and SCLC CTC cell lines that have been established at the Medical University of Vienna.

Methods

Five CTC and SCLC lines were analyzed using a TF enzyme-linked immunosorbent assay (ELISA) tests, RNA sequencing, and western blot arrays covering 55 angiogenic mediators. Furthermore, the influence of topotecan and epirubicin as well as hypoxia-like conditions on the expression of these mediators was investigated.

Results

The results demonstrate that the SCLC CTC cell lines express no significant amounts of active TF but thrombospondin-1 (TSP-1), urokinase-type plasminogen activator receptor (uPAR), vascular endothelial-derived growth factor (VEGF) and angiopoietin-2 in two cases. The major difference between the SCLC and SCLC CTC cell lines found was the loss of the expression of angiogenin in the blood-derived CTC lines. Topotecan and epirubicin decreased the expression of VEGF, whereas hypoxia-like conditions upregulated VEGF.

Conclusions

Active TF capable of triggering coagulation seems not to be expressed in SCLC CTC cell lines in significant levels and, thus, CTC-derived TF seems dispensable for dissemination. Nevertheless, all CTC lines form large spheroids, termed tumorospheres, which may become trapped in clots of the microvasculature and extravasate in this supportive microenvironment. The contribution of clotting to the protection and dissemination of CTCs in SCLC may be different from other solid tumors such as breast cancer.

Hemostatic Biomarkers and Cancer Prognosis: Where Do We Stand?

Cancer patients are characterized by hypercoagulable state and an increased rate of thrombotic events, the most common being venous thromboembolism. Several hemostatic pathways that are significantly implicated in mechanisms of thromboembolic disease are also involved in growth, invasion, and metastatic spread of malignant cells as well in tumor-induced neo-angiogenesis. This close connection between cancer and the hemostatic system has prompted numerous studies on the role of alterations in the level plasma biomarkers of the different compartments of hemostasis in predicting cancer prognosis. In this review, we collect the results of several exemplificative studies that have evaluated clotting activation biomarkers in relation to different cancer outcomes with a final emphasis on current research and forthcoming directions in this field.

Cancer-Associated Splanchnic Vein Thrombosis

Splanchnic vein thrombosis (SVT), which includes portal, mesenteric, and splenic vein thrombosis and the Budd-Chiari syndrome, is an infrequent manifestation of venous thromboembolism (VTE). Like typical site VTE, SVT is also frequently associated with cancer, particularly intra-abdominal solid malignancies and myeloproliferative neoplasms (MPNs). The clinical presentation of SVT is nonspecific. Symptoms may be related to the underlying malignancy, and thrombosis is incidentally diagnosed by imaging studies for cancer staging or follow-up in a substantial proportion of cases. The occurrence of SVT predicts worse prognosis in patients with liver or pancreatic cancer and, not uncommonly, SVT may precede the diagnosis of cancer. Therefore, the occurrence of an apparently unprovoked SVT should prompt careful patient evaluation for the presence of an underlying malignancy or MPN. Cancer patients carry a high risk of VTE extension and recurrence and long-term anticoagulant treatment is suggested in the absence of high risk of bleeding. Either LMWH or direct oral anticoagulants (DOACs) are suggested for the treatment of patients with cancer-related SVT, although limited experience is available on the use of DOACs in these settings. Vitamin K antagonists (VKAs) are suggested for the short and long-term treatment of SVT associated with MPN. This review outlines the epidemiological aspects, pathogenesis, risk factors, and diagnosis of cancer-associated SVT, and addresses questions regarding the management of this challenging condition.

Clinical Benefits of Oral Anticoagulant Use in Cancer Patients at Increased Risk for Venous Thromboembolism per Khorana Index

Background

Cancer patients are at increased risk for venous thromboembolism (VTE) due to cancer-induced hypercoagulability. However, current guidelines do not routinely recommend prophylactic use of oral anticoagulants to prevent VTE in cancer patients.

Objective

To evaluate the efficacy and safety of novel oral anticoagulants (NOACs) versus no anticoagulant use (no-use) and, additionally, differential effects between NOACs and warfarin, in VTE and adverse bleeding prevention among cancer patients, in consideration of risk stratification by gender, high-risk chemotherapy exposure, and Khorana index.

Methods

This national health insurance data-based study with a 180-day follow-up enrolled cancer patients with or without oral anticoagulant use in 2017. The primary outcome was VTE risk in oral anticoagulant users vs non-users. Four propensity score-matched comparison pairs were designed: use vs no-use, NOAC vs no-use, warfarin vs no-use, and NOAC vs warfarin. A logistic regression model was used to investigate between-group differences in VTE and bleeding risk.

Results

When compared to no-use, NOACs showed substantial effects in preventing VTE complications (OR=0.40, p<0.001), primarily deep vein thrombosis (DVT) events (OR=0.38, p<0.001), in both male and female cancer patients as well as those with a Khorana score ≥1. Adverse bleeding risk was comparable or lower in NOAC-receiving female patients (p=0.13) and male patients (p=0.04), respectively. In contrast, no protective effects were found with warfarin compared to no-use in controlling thrombosis and adverse bleeding risk. In a head-to-head comparison of NOACs versus warfarin, DVT risk in those patients exposed to high-risk chemotherapy was significantly decreased with NOAC use (OR=0.19, p=0.03).

Conclusion

NOACs can be a promising thromboprophylactic option in both male and female cancer patients with VTE risk.

Splanchnic Vein Thrombosis: Current Perspectives

Splanchnic vein thrombosis (SVT) including portal, mesenteric, splenic vein thrombosis and the Budd-Chiari syndrome, is a manifestation of unusual site venous thromboembolism. SVT presents with a lower incidence than deep vein thrombosis of the lower limbs and pulmonary embolism, with portal vein thrombosis and Budd-Chiari syndrome being respectively the most and the least common presentations of SVT. SVT is classified as provoked if secondary to a local or systemic risk factor, or unprovoked if the causative trigger cannot be identified. Diagnostic evaluation is often affected by the lack of specificity of clinical manifestations: the presence of one or more risk factors in a patient with a high clinical suspicion may suggest the execution of diagnostic tests. Doppler ultrasonography represents the first line diagnostic tool because of its accuracy and wide availability. Further investigations, such as computed tomography and magnetic resonance angiography, should be executed in case of suspected thrombosis of the mesenteric veins, suspicion of SVT-related complications, or to complete information after Doppler ultrasonography. Once SVT diagnosis is established, a careful patient evaluation should be performed in order to assess the risks and benefits of the anticoagulant therapy and to drive the optimal treatment intensity. Due to the low quality and large heterogeneity of published data, guidance documents and expert opinion could direct therapeutic decision, suggesting which patients to treat, which anticoagulant to use and the duration of treatment.

A clinical research on the potential pathogenesis of somatic cancer related cerebral venous sinus thrombosis

To investigate the pathogenesis of somatic solid cancer-related cerebral venous sinus thrombosis (CVST).A total of 174 patients with CVST were recruited from the hospital between January 2006 and December 2017 and divided into two groups: (1) somatic cancer-related CVST group, defined as active somatic solid cancer patients with acute CVST; (2) cancer group (CG), defined as active somatic solid cancer patients without CVST. The cancer group patients were age and gender-matched somatic cancer-related CVST group patients. In addition, the types and amount distribution of cancer in cancer group were also matched with somatic cancer-related CVST group patients.Compared to cancer group patients, somatic cancer-related CVST group patients had more intracranial metastasis, a higher platelet count, higher plasma D-dimer, carcinoembryonic antigen (CEA) and cancer antigen (CA) 125 levels, a greater platelet to lymphocyte ratio (PLR), and a greater platelet to neutrophil ratio (PNR). The risk for CVST in somatic cancer-related CVST group patients increased independently by 0.7% (odds ratio [OR] 1.007; 95% confidence interval [CI] 1.000, 1.015; P = .047) with a 1 ng/ml increase in D-dimer levels, by 4.6% (OR 1.046; 95% CI 1.011, 1.083; P = .010) with a 1 U/ml increase in CEA, by 2.7% (OR 1.027; 95% CI 1.003, 1.051; P = .025) with a 1 U/ml increase in CA125, and by 10.6% (OR 1.106; 95% CI 1.002, 1.220; P = .045) with a 1 unit increase in PNR.It was suggested that together impacts of elevated plasma D-dimer, CA125, CEA levels, and a greater PNR may lead to hypercoagulability and to trigger the development of cancer-related CVST.

Extracellular Vesicles in Cancer: Purpose and Promise

Extracellular vesicles refer collectively to a heterogeneous group of membrane-bound vesicles released from cells and loaded with bioactive proteins, nucleic acids, and lipids. The concept of extracellular vesicles has rapidly evolved from once being viewed as cellular debris to their recognition as packets of cellular information with considerable promise for clinical applications as biomarker platforms and therapeutic vehicles. These shed vesicles have emerged as critical mediators of intercellular communication in both local and distant microenvironments during normal physiological processes, as well as in orchestrating systemic pathophysiological events in disease. This mode of cellular crosstalk is particularly relevant to modulating the tumor microenvironment and orchestrating paths of least resistance during metastases. Here, we describe recent advances for the roles of extracellular vesicles in tumor progression and their potential as disease biomarkers.

Roles of Coagulation Proteases and PARs (Protease-Activated Receptors) in Mouse Models of Inflammatory Diseases

Activation of the blood coagulation cascade leads to fibrin deposition and platelet activation that are required for hemostasis. However, aberrant activation of coagulation can lead to thrombosis. Thrombi can cause tissue ischemia, and fibrin degradation products and activated platelets can enhance inflammation. In addition, coagulation proteases activate cells by cleavage of PARs (protease-activated receptors), including PAR1 and PAR2. Direct oral anticoagulants have recently been developed to specifically inhibit the coagulation proteases FXa (factor Xa) and thrombin. Administration of these inhibitors to wild-type mice can be used to determine the roles of FXa and thrombin in different inflammatory diseases. These results can be compared with the phenotypes of mice with deficiencies of either Par1 (F2r) or Par2 (F2rl1). However, inhibition of coagulation proteases will have effects beyond reducing PAR signaling, and a deficiency of PARs will abolish signaling from all proteases that activate these receptors. We will summarize studies that examine the roles of coagulation proteases, particularly FXa and thrombin, and PARs in different mouse models of inflammatory disease. Targeting FXa and thrombin or PARs may reduce inflammatory diseases in humans.

Hemostatic biomarkers in cancer progression

Malignant disease is characterized by a hemostatic imbalance, usually shifted towards a procoagulant direction, and a high incidence of thrombotic complications. The mechanisms of hemostasis that are critically involved in thrombosis are also implicated in tumor progression, angiogenesis, and metastatic spread. As there is a close relationship between cancer and the clotting system, circulating biomarkers of activation of various hemostasis compartments (i.e. coagulation, fibrinolysis, platelets, endothelium, and other blood cells) have been extensively studied to predict cancer outcomes along with predicting the thrombotic risk. In this review, we will summarize the results of published studies and will focus on ongoing research and future directions of clotting activation bioproducts as biomarkers of cancer disease and progression.

YAP and MRTF-A, transcriptional co-activators of RhoA-mediated gene expression, are critical for glioblastoma tumorigenicity

The role of YAP (Yes-associated protein 1) and MRTF-A (myocardin-related transcription factor A), two transcriptional co-activators regulated downstream of GPCRs (G protein-coupled receptors) and RhoA, in the growth of glioblastoma cells and in vivo glioblastoma multiforme (GBM) tumor development was explored using human glioblastoma cell lines and tumor-initiating cells derived from patient-derived xenografts (PDX). Knockdown of these co-activators in GSC-23 PDX cells using short hairpin RNA significantly attenuated in vitro self-renewal capability assessed by limiting dilution, oncogene expression, and neurosphere formation. Orthotopic xenografts of the MRTF-A and YAP knockdown PDX cells formed significantly smaller tumors and were of lower morbidity than wild-type cells. In vitro studies used PDX and 1321N1 glioblastoma cells to examine functional responses to sphingosine 1-phosphate (S1P), a GPCR agonist that activates RhoA signaling, demonstrated that YAP signaling was required for cell migration and invasion, whereas MRTF-A was required for cell adhesion; both YAP and MRTF-A were required for proliferation. Gene expression analysis by RNA-sequencing of S1P-treated MRTF-A or YAP knockout cells identified 44 genes that were induced through RhoA and highly dependent on YAP, MRTF-A, or both. Knockdown of F3 (tissue factor (TF)), a target gene regulated selectively through YAP, blocked cell invasion and migration, whereas knockdown of HBEGF (heparin-binding epidermal growth factor-like growth factor), a gene selectively induced through MRTF-A, prevented cell adhesion in response to S1P. Proliferation was sensitive to knockdown of target genes regulated through either or both YAP and MRTF-A. Expression of TF and HBEGF was also selectively decreased in tumors from PDX cells lacking YAP or MRTF-A, indicating that these transcriptional pathways are regulated in preclinical GBM models and suggesting that their activation through GPCRs and RhoA contributes to growth and maintenance of human GBM.

Tissue factor mediates microvesicles shedding from MDA-MB-231 breast cancer cells

Extracellular vesicles, such as microvesicles (MVs), were identified as important players in tumor progression and acquisition of an aggressive phenotype. Tissue factor (TF) is a transmembrane protein that initiates the blood coagulation cascade. In tumor cells, TF has been associated with aggressiveness and cancer progression. Previous studies demonstrate that TF is incorporated into MVs secreted by tumor cells; however, it is unknown whether TF is actively involved in the release of MVs. Here, we investigated the influence of TF expression on the release of MVs. TF silencing was achieved through CRISPR/Cas9 approaches in the human breast cancer cell line, MDA-MB-231. TF knockout in MDA-MB-231 cells efficiently reduced TF-dependent signaling and procoagulant activity. Remarkably, silencing of TF caused a significant decrease in the number of MVs released by MDA-MB-231 cells. We also observed an increase in actin-positive membrane projections in TF knockout cells and a reduction in RhoA expression when compared to TF-expressing cells. Treatment of MDA-MB-231 cells with the RhoA-ROCK signaling pathway inhibitor, fasudil, significantly reduced the release of MVs. Taken together, our results suggest a novel and relevant role for TF in tumor biology by playing an active role in the MVs secretion.

The role of plasma D-dimer levels for predicting lymph node and mediastinal lymph node involvement in non-small cell lung cancer

INTRODUCTION

Elevated plasma D-dimer levels have been suggested as a predictor of poor prognosis in NSCLC. But rare study showed the relationship between D-dimer levels and lymph node involvement.

OBJECTIVES

To evaluate the role of plasma D-dimer levels in predicting lymph node and mediastinal lymph node involvement in NSCLC.

METHODS

Preoperative plasma D-dimer levels were quantified in 253 NSCLC patients that underwent radical lung resection with systemic lymph node dissection. Patients were classified as lymph node negative (N0) versus lymph node positive (N1 + N2) and mediastinal lymph node negative (N0 + N1) versus mediastinal lymph node positive (N2).

RESULTS

Median plasma D-dimer level was significantly lower in Group N0 (94.0 μg/L) compared to Group N1 + N2 (177.0 μg/L) and in Group N0 + N1 (122.0 μg/L) compared to Group N2 (198.0 μg/L). Similar results were found in patients stratified by age, sex, smoking status and histological type, expect in patients with squamous carcinoma. The Receiver Operating Characteristic (ROC) curve for plasma D-dimer levels of N0 versus N1 + N2 showed an area under the curve (AUC) of 0.757 and when a cutoff value was 124.0 μg/L DDU, the sensitivity and specificity was 0.80 and 0.68. The ROC curve for plasma D-dimer levels of N0 + N1 versus N2 showed an AUC of 0.720 and when a cutoff value was 147.0 μg/L DDU, the sensitivity and specificity was 0.75 and 0.67.

CONCLUSIONS

Plasma D-dimer level has utility for predicting lymph node and mediastinal lymph node status in patients with operable NSCLC.

Chimeric antigen receptor-modified T Cells inhibit the growth and metastases of established tissue factor-positive tumors in NOG mice

Chimeric antigen receptor (CAR)-modified T cell (CAR T) is a promising therapeutic option for patients with cancer. Such an approach requires the identification of tumor-specific antigen targets that are expressed in solid tumors. We developed a new third-generation CAR directed against tissue factor (TF), a surface molecule overexpressed in some types of lung cancer, melanoma and other cancers. First, we demonstrated by immunohistochemistry that TF was overexpressed in squamous cell carcinoma and adenocarcinoma of non-small cell lung cancer (NSCLC) and melanoma using a human tissue microarray. In the presence of TF-positive cancer cells, the CAR-modified T cells (TF-CAR T) were highly activated and showed specific cytotoxicity to TF-positive cancer cells in vitro. In established s.c. xenograft and lung metastasis models, TF-CAR T cells could significantly suppress the growth of s.c. xenograft and metastasis of TF-positive cancer cells. Additionally, the safety evaluation of TF-CAR T cells in vivo showed that the treatment did not cause obvious toxicity in mice. Taken together, these findings indicate that TF-CAR T cells might be a novel potential therapeutic agent for the treatment of patients with TF-positive cancers.

Malignant transformation in melanocytes is associated with increased production of procoagulant microvesicles

Shedding of microvesicles (MVs) by cancer cells is implicated in a variety of biological effects, including the establishment of cancer-associated hypercoagulable states. However, the mechanisms underlying malignant transformation and the acquisition of procoagulant properties by tumour-derived MVs are poorly understood. Here we investigated the procoagulant and prothrombotic properties of MVs produced by a melanocyte-derived cell line (melan-a) as compared to its tumourigenic melanoma counterpart Tm1. Tumour cells exhibit a two-fold higher rate of MVs production as compared to melan-a. Melanoma MVs display greater procoagulant activity and elevated levels of the clotting initiator protein tissue factor (TF). On the other hand, tumour- and melanocyte- derived MVs expose similar levels of the procoagulant lipid phosphatidylserine, displaying identical abilities to support thrombin generation by the prothrombinase complex. By using an arterial thrombosis model, we observed that melanoma- but not melanocyte-derived MVs strongly accelerate thrombus formation in a TF-dependent manner, and accumulate at the site of vascular injury. Analysis of plasma obtained from melanoma-bearing mice showed the presence of MVs with a similar procoagulant pattern as compared to Tm1 MVs produced in vitro. Remarkably, flow-cytometric analysis demonstrated that 60% of ex vivo MVs are TF-positive and carry the melanoma-associated antigen, demonstrating its tumour origin. Altogether our data suggest that malignant transformation in melanocytes increases the production of procoagulant MVs, which may contribute for a variety of coagulation- related protumoural responses.

Coagulation and fibrinolysis in gastric cancer

Coagulation is a highly conserved process occurring after an injury to a blood vessel and resulting in hemostasis. In the thrombus microenvironment, finely orchestrated events restore vessel integrity through platelet activation, adhesion, and aggregation (primary hemostasis), followed by the coagulation cascades, thrombin generation, and fibrin clot deposition (secondary hemostasis). Several studies on cancer have provided insight into dramatic changes to coagulation-related events (i.e., fibrin clot deposition, fibrinolysis) during tumor pathogenesis, progression, and metastasis, in addition to a tumor-driven systemic activation of hemostasis and thrombosis (Trousseau's syndrome). Diverse molecular and cellular effectors participate in the cross talk between hemostasis and tumors. Here, we focus on some aspects of the interconnection between cancer biology and hemostatic components, with particular attention to some key coagulation-related proteins (e.g., tissue factor, thrombin, fibrinogen, and D-dimers) in the particular case of gastric cancer (GC). Recent advances in deciphering the complex molecular link between GC and the coagulation system are described, showing their important roles in better management of patients affected by GC.

The prognostic value of D-dimer levels in endometrial cancer patients treated with intensity-modulated radiation therapy

Explain the important role of plasma D-dimer in cancers. Plasma D-dimer is increased in various tumors. However, the predictive value of plasma D-dimer is unclear. This study is aimed to evaluate the prognostic value of the D-dimer level in patients managed with intensity-modulated radiation for endometrial cancer. The D-dimer levels of forty patients with endometrial cancer were assessed before (D1) and after (D2) intensity-modulated radiation therapy (IMRT), respectively. The D-dimer level changes (ΔD) were defined as D2 minus D1. Cox regression and log-rank tests were used to evaluate the D-dimer levels in relation to progression free survival (PFS) and overall survival (OS). The OS and PFS of patients with a low D1 were significantly longer than those with a high D1 (P< 0.001, P< 0.001). We saw the similar correlation between D2, PFS and OS (P< 0.001, P< 0.001). Multivariate survival analyses showed that D-dimer was independently associated with OS and PFS in patients with endometrial cancer. The ΔD level was not related to the OS and PFS in endometrial cancer patients. The levels of D-dimer may be considered as an important predictor of PFS and OS in endometrial cancer patients treated with IMRT.

Interrelation of blood coagulation and hemorheology in cancer

Cancer progression is associated with activation of blood coagulation. Blood coagulation process, platelet hemostasis and hemorheological properties were evaluated in patients with solid tumors (n = 27) before and after surgery and in healthy control (n = 20). The main features of blood coagulation process in cancer patients were elevated intensity and shortened period of contact phase of coagulation and inhibited fibrinolysis stage. Such prothrombotic state was fixed before surgery as well as in early postoperative period in spite of preventing thromboprophylactic treatment. Platelets depletion within the high level of spontaneous and ADP-induced platelet aggregation was fixed in cancer. The main cause of blood viscosity decrease in cancer patients was dramatic fall of Hct, because blood viscosity adjusted by Hct 40% was increased owing to the rise of plasma viscosity and substantially worsened RBC microrheological properties. The results of our study indicated close correlation between hemorheological and hemostasis parameters; these interrelations were more numerous and strong in cancer. In cancer patients the combination of a high aggregation activity of platelets, reduced number of erythrocytes (Hct), an increase of RBC aggregation and plasma viscosity caused impairment of blood oxygen transportation efficacy that provoke hypoxia in the microcirculation favoring thrombosis, settlement of tumor and metastasis.

Hypoxia regulates the expression of tissue factor pathway signaling elements in a rat glioma model

Hypoxia and necrosis are fundamental features of glioma, and their emergence is critical for the rapid biological progression of this fatal tumor. The presence of vaso-occlusive thrombus is higher in grade IV tumors [glioblastoma multiforme (GBM)] compared with lower grade tumors, suggesting that the procoagulant properties of the tumor contribute to its aggressive behavior, as well as the establishment of tumor hypoxia and necrosis. Tissue factor (TF), the primary cellular initiator of coagulation, is overexpressed in GBMs and likely favors a thrombotic microenvironment. Phosphatase and tensin homolog (PTEN) loss and hypoxia are two common alterations observed in glioma that may be responsible for TF upregulation. In the present study, ST1 and P7 rat glioma lines, with different levels of aggressiveness, were comparatively analyzed with the aim of identifying differences in procoagulant mechanisms. The results indicated that P7 cells display potent procoagulant activity compared with ST1 cells. Flow cytometric analysis showed less pronounced levels of TF in ST1 cells compared with P7 cells. Notably, P7 cells supported factor X (FX) activation via factor VIIa, whereas no significant FXa generation was observed in ST1 cells. Furthermore, the exposure of phosphatidylserine on the surface of P7 and ST1 cells was investigated. The results supported the assembly of prothrombinase complexes, accounting for the production of thrombin. Furthermore, reverse transcription-quantitative polymerase chain reaction showed that CoCl₂ (known to induce a hypoxic-like stress) led to an upregulation of TF levels in P7 and ST1 cells. Therefore, increased TF expression in P7 cells was accompanied by increased TF procoagulant activity. In addition, hypoxia increased the shedding of procoagulant TF-bearing microvesicles in both cell lines. Finally, hypoxic stress induced by treatment with CoCl₂ upregulated the expression of the PAR1 receptor in both P7 and ST1 cells. In addition to PAR1, P7, but not ST1 cells, expressed higher levels of PAR2 under hypoxic stress. Thus, modulating these molecular interactions may provide additional insights for the development of more efficient therapeutic strategies against aggressive glioma.

Therapeutic Potential of miR-494 in Thrombosis and Other Diseases: A Review

Functional nucleic acids, such as microRNAs (miRNAs), have been implicated in the pathophysiology of many diseases. The miRNA expression profiles of various cancers including haematological malignancies are well defined, but the role of miRNAs in haemostasis and the regulation of coagulation is poorly understood. We identified that miR-494 is oestrogen responsive and directly targets the anticoagulant protein, Protein S, as a mechanism for acquiring Protein S deficiency under high oestrogenic conditions such as during pregnancy and oral contraceptive use. Furthermore, previous studies have also characterised miR-494 to be involved in many biological processes. This paper reviews the current knowledge in the role of miRNAs in regulating haemostatic proteins and the known biological functions of miR-494, highlighting miR-494 as an emerging therapeutic target, with an overview of the strategy we have employed in identifying functional nucleic acids such as miRNAs that target haemostatic factors and the therapeutic potential of miR-494-directed therapy for the treatment of thrombotic disorders.

Effect of 10 different polymorphisms on preoperative volumetric characteristics of glioblastoma multiforme

There is a distinct diversity between the appearance of every glioblastoma multiforme (GBM) on pretreatment magnetic resonance imaging (MRI) with a potential impact on clinical outcome and survival of the patients. The object of this study was to determine the impact of 10 different single nucleotide polymorphisms (SNPs) on various volumetric parameters in patients harboring a GBM. We prospectively analyzed 20 steroid-naïve adult patients who had been treated for newly diagnosed GBM. The volumetry was performed using MRI with the help of a semiautomated quantitative software measuring contrast enhancing tumor volume including necrosis, central necrosis alone and peritumoral edema (PTE). We calculated ratios between the tumor volume and edema (ETR), respectively necrosis (NTR). SNP analysis was done using genomic DNA extracted from peripheral blood genotyped via PCR and sequencing. There was a strong correlation between tumor volume and PTE (p < 0.001), necrosis (p < 0.001) and NTR (p = 0.003). Age and sex had no influence on volumetric data. The Aquaporin 4-31G > A SNP had a significant influence on the ETR (p = 0.042) by decreasing the measured edema compared with the tumor volume. The Interleukin 8-251A > T SNP was significantly correlated with an increased tumor (p = 0.048), PTE (p = 0.033) and necrosis volume (p = 0.028). We found two SNPs with a distinct impact on pretreatment tumor characteristics, presenting a potential explanation for the individual diversity of GBM appearance on MRI and influence on survival.

CUSP9* treatment protocol for recurrent glioblastoma: aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, ritonavir, sertraline augmenting continuous low dose temozolomide

CUSP9 treatment protocol for recurrent glioblastoma was published one year ago. We now present a slight modification, designated CUSP9*. CUSP9* drugs--aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, sertraline, ritonavir, are all widely approved by regulatory authorities, marketed for non-cancer indications. Each drug inhibits one or more important growth-enhancing pathways used by glioblastoma. By blocking survival paths, the aim is to render temozolomide, the current standard cytotoxic drug used in primary glioblastoma treatment, more effective. Although esthetically unpleasing to use so many drugs at once, the closely similar drugs of the original CUSP9 used together have been well-tolerated when given on a compassionate-use basis in the cases that have come to our attention so far. We expect similarly good tolerability for CUSP9*. The combined action of this suite of drugs blocks signaling at, or the activity of, AKT phosphorylation, aldehyde dehydrogenase, angiotensin converting enzyme, carbonic anhydrase -2,- 9, -12, cyclooxygenase-1 and -2, cathepsin B, Hedgehog, interleukin-6, 5-lipoxygenase, matrix metalloproteinase -2 and -9, mammalian target of rapamycin, neurokinin-1, p-gp efflux pump, thioredoxin reductase, tissue factor, 20 kDa translationally controlled tumor protein, and vascular endothelial growth factor. We believe that given the current prognosis after a glioblastoma has recurred, a trial of CUSP9* is warranted.

Preoperative D-dimers as an independent prognostic marker in cervical carcinoma

Activation of coagulation and fibrinolysis has been observed in many tumors. Our study aimed to investigate the clinical and prognostic significance of various plasma coagulation tests in patients with cervical cancer. A total of 296 patients with cervical cancer were included in the analysis. Patients were followed up for at least 60 months until death. Pretreatment parameters including activated partial thromboplastin time, D-dimer, fibrinogen, prothrombin time, thrombin time, lactate dehydrogenase, and squamous cell carcinoma antigen were evaluated. Prothrombin time (hazard ratio = 1.825; P = 0.006) and plasma D-dimer levels (hazard ratio = 2.179; P = 0.036) were identified as significant independent predictors of overall survival. Patients with elevated D-dimer levels had a significantly shorter overall survival compared with those with low-D-dimer levels (<0.5 μg/ml) in the stage I subgroup (n = 98, P = 0.019) and stage II subgroup (n = 77, P = 0.044). D-dimer levels differed significantly according to mortality (P < 0.001), stage I versus stage II (P = 0.030), and stage I versus stage III/IV (P = 0.038). DD level of patients with chemotherapy and/or radiotherapy was higher than patients with other treatment (P < 0.001). Patients with a low-D-dimer level (<0.5 μg/ml) showed a significantly better 5-year overall survival (OS) compared with patients with an increased D-dimer level for different histological typing of squamous cell carcinoma (SCC) (P = 0.001) and non-SCC (P < 0.043). In conclusion, the pretreatment plasma D-dimer level is a potential prognostic factor for cervical cancer.

(99m)Tc-ixolaris targets glioblastoma-associated tissue factor: in vitro and pre-clinical applications

BACKGROUND

The clotting initiator protein tissue factor (TF) has recently been described as a potential target that can be exploited to image aggressive tumors. Ixolaris is a specific TF inhibitor that blocks tumor cell procoagulant activity and tumor growth.

OBJECTIVE

Herein we evaluated the ability of (99m)Tc-ixolaris to target tumor-derived TF using an orthotopic glioblastoma (GBM) model in mice.

METHODS

The right forebrains of Swiss mice were stereotactically inoculated with U87-MG human GBM cells. Histological and immunohistochemical analyses were performed on the resulting tumors after 35-45 days. The biodistribution of (99m)Tc-ixolaris was evaluated by semi-quantitative whole-body scintigraphy and a quantitative analysis of radioactivity in isolated organs.

RESULTS

No (99m)Tc-ixolaris uptake was observed in brain of tumor-free mice, independently of the integrity of brain-blood barrier. In contrast, the presence of TF-expressing brain tumor masses determined a significant (99m)Tc-ixolaris uptake.

CONCLUSION

(99m)Tc-ixolaris recognized TF-expressing GBM cells in vivo. Given the proposed role of TF in tumor progression, (99m)Tc-ixolaris is a promising radiopharmaceutical agent for quantifying cancer-associated TF in aggressive tumors, including GBM.

Tissue factor-expressing tumor cells can bind to immobilized recombinant tissue factor pathway inhibitor under static and shear conditions in vitro

Mammary tumors and malignant breast cancer cell lines over-express the coagulation factor, tissue factor (TF). High expression of TF is associated with a poor prognosis in breast cancer. Tissue factor pathway inhibitor (TFPI), the endogenous inhibitor of TF, is constitutively expressed on the endothelium. We hypothesized that TF-expressing tumor cells can bind to immobilized recombinant TFPI, leading to arrest of the tumor cells under shear in vitro. We evaluated the adhesion of breast cancer cells to immobilized TFPI under static and shear conditions (0.35 – 1.3 dyn/cm²). We found that high-TF-expressing breast cancer cells, MDA-MB-231 (with a TF density of 460,000/cell), but not low TF-expressing MCF-7 (with a TF density of 1,400/cell), adhered to recombinant TFPI, under static and shear conditions. Adhesion of MDA-MB-231 cells to TFPI required activated factor VII (FVIIa), but not FX, and was inhibited by a factor VIIa-blocking anti-TF antibody. Under shear, adhesion to TFPI was dependent on the TFPI-coating concentration, FVIIa concentration and shear stress, with no observed adhesion at shear stresses greater than 1.0 dyn/cm². This is the first study showing that TF-expressing tumor cells can be captured by immobilized TFPI, a ligand constitutively expressed on the endothelium, under low shear in vitro. Based on our results, we hypothesize that TFPI could be a novel ligand mediating the arrest of TF-expressing tumor cells in high TFPI-expressing vessels under conditions of low shear during metastasis.

Thrombomodulin modulates cell migration in human melanoma cell lines

Malignant melanoma cells are known to have altered expressions of growth factors as compared with normal melanocytes. Thrombomodulin (TM) is a thrombin receptor on endothelial cells that converts thrombin from a procoagulant to an anticoagulant enzyme. TM expression is downregulated in tumor cells, and this phenomenon correlates with tumor cell invasiveness and a poor prognosis in patients with cancer. In this study, we evaluated TM expression in two human melanoma cell lines that are known to have either low (WM35) or high (A375) aggressive phenotypes. Analysis by quantitative real-time PCR (qPCR) showed that the mRNA expression of TM is modestly (WM35) or dramatically (A375) downregulated in melanoma cells, as compared with human primary melanocytes. TM expression levels inversely correlated with in-vitro migration properties of tumor cells. In addition, interleukin-8 expression also correlated with the degree of aggressiveness, as indicated by high expression levels of this cytokine in A375 cells. Overexpression of TM in A375 cells by transient transfection reversed their aggressive phenotype and dramatically decreased interleukin-8 expression by these cells. Taken together, these results suggest that downregulation of TM plays a crucial role in melanocyte transformation and melanoma progression.

Interconnections between autophagy and the coagulation cascade in hepatocellular carcinoma

Autophagy has an important role in tumor biology of hepatocellular carcinoma (HCC). Recent studies demonstrated that tissue factor (TF) combined with coagulation factor VII (FVII) has a pathological role by activating a G-protein-coupled receptor called protease-activated receptor 2 (PAR2) for tumor growth. The present study aimed to investigate the interactions of autophagy and the coagulation cascade in HCC. Seventy HCC patients who underwent curative liver resection were recruited. Immunohistochemical staining and western blotting were performed to determine TF, FVII, PAR2 and light chain 3 (LC3A/B) expressions in tumors and their contiguous normal regions. We found that the levels of autophagic marker LC3A/B-II and coagulation proteins (TF, FVII and PAR2) were inversely correlated in human HCC tissues. Treatments with TF, FVII or PAR2 agonist downregulated LC3A/B-II with an increased level of mTOR in Hep3B cells; in contrast, knockdown of TF, FVII or PAR2 increased LC3A/B. Furthermore, mTOR silencing restored the impaired expression of LC3A/B-II in TF-, FVII- or PAR2-treated Hep3B cells and activated autophagy. Last, as an in vivo correlate, we administered TF, FVII or PAR2 agonist in a NOD/severe combined immunodeficiency xenograft model and showed decreased LC3A/B protein levels in HepG2 tumors with treatments. Overall, our present study demonstrated that TF, FVII and PAR2 regulated autophagy mainly via mTOR signaling. The interaction of coagulation and autophagic pathways may provide potential targets for further therapeutic application in HCC.

Expression of tissue factor signaling pathway elements correlates with the production of vascular endothelial growth factor and interleukin-8 in human astrocytoma patients

The expression levels of tissue factor (TF), the clotting initiator protein, have been correlated with angiogenesis and the histological grade of malignancy in glioma patients. The pro-tumor function of TF is linked to a family of G protein-coupled receptors known as protease-activated receptors (PARs), which may be activated by blood coagulation proteases. Activation of PARs elicits a number of responses, including the expression of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8). In the present study, we analyzed the expression of TF signaling pathway elements (TF, PAR1 and PAR2) and evaluated their correlation with the expression of downstream products (VEGF and IL-8) in human astrocytoma patients. Quantitative PCR (qPCR) showed a significant increase in TF expression in grade IV (glioblastoma) tumors, which was inversely correlated with the expression of the tumor-suppressor PTEN. Immunohistochemistry and qPCR analyses demonstrated a highly significant elevation in the expression of PAR1, but not PAR2, in tumor samples from high-grade astrocytoma patients. The elevated VEGF expression levels detected in the high-grade astrocytoma samples were positively correlated with TF, PAR1 and PAR2 expression. In addition, IL-8 was significantly increased in glioblastoma patients and positively correlated with TF and PAR2 expression. Further in vitro assays employing the human glioma cell lines U87-MG and HOG demonstrated that a synthetic peptide PAR2 agonist stimulated VEGF and IL-8 production. Our findings suggest a role for TF signaling pathway elements in astrocytoma progression, particularly in glioblastoma. Therefore, TF/PAR signaling elements may be suitable targets for the development of new therapies for the treatment of aggressive glioma.

Activation of blood coagulation in cancer: implications for tumour progression

Several studies have suggested a role for blood coagulation proteins in tumour progression. Herein, we discuss (1) the activation of the blood clotting cascade in the tumour microenvironment and its impact on primary tumour growth; (2) the intravascular activation of blood coagulation and its impact on tumour metastasis and cancer-associated thrombosis; and (3) antitumour therapies that target blood-coagulation-associated proteins. Expression levels of the clotting initiator protein TF (tissue factor) have been correlated with tumour cell aggressiveness. Simultaneous TF expression and PS (phosphatidylserine) exposure by tumour cells promote the extravascular activation of blood coagulation. The generation of blood coagulation enzymes in the tumour microenvironment may trigger the activation of PARs (protease-activated receptors). In particular, PAR1 and PAR2 have been associated with many aspects of tumour biology. The procoagulant activity of circulating tumour cells favours metastasis, whereas the release of TF-bearing MVs (microvesicles) into the circulation has been correlated with cancer-associated thrombosis. Given the role of coagulation proteins in tumour progression, it has been proposed that they could be targets for the development of new antitumour therapies.

Tissue factor-targeted lidamycin inhibits growth and metastasis of colon carcinoma

Colon cancer is the third most common cancer in the world. The overexpression of tissue factor (TF) in colon cancer cells makes it an ideal target for colon cancer therapy. The purpose of the present study was to develop a TF-targeting energized fusion protein, mlFVII-LDP-AE, which is composed of a mouse Factor VII light chain (mlFVII) as the targeting domain conjugated to the highly cytotoxic antibiotic lidamycin (LDM, LDP-AE) as the effector domain. The potential efficacy of mlFVII-LDP-AE for mouse colon cancer therapy was tested in a mouse colon cancer subcutaneous xenograft model and a live metastasis model in BALB/c mice. mlFVII-LDP-AE showed a tumor growth inhibition rate of 91.2% (at a dose of 0.8 mg/kg) and a tumor metastasis inhibition rate of 84.7% (at a dose of 0.6 mg/kg). The results showed that mlFVII-LDP-AE was able to effectively inhibit the growth and metastasis of mouse colon cancer. As human TF and FVII have features similar to those of mice, human FVII light chain (hlFVII)-targeted LDM (hlFVII-LDP-AE) may be expected to have therapeutic potential for human colon cancer.

Early growth response gene-1 and hypoxia-inducible factor-1α affect tumor metastasis via regulation of tissue factor

BACKGROUND

Hypoxia up-regulated expression of tissue factor (TF) may facilitate tumor cell metastasis, but transcriptional mechanisms remain undefined.

MATERIAL AND METHODS

To verify the role of Egr-1 in hypoxia-induced TF expression in breast cancer cells, quantitative PCR and Western blot analysis were performed. The secretion of VEGF under hypoxia was detected by enzyme-linked immunosorbent assay (ELISA). Egr-1 and HIF-1α siRNA were transiently transfected into breast cancer cells to evaluate their specific roles.

RESULTS

The increased Egr-1 expression occurring in hypoxic breast cancer cells can up-regulate TF expression and stimulating protein 1(Sp1) was not responsible for the hypoxia-induced expression of TF. HIF-1α mediated the hypoxia-induced up-regulation of TF expression through vascular endothelial growth factor (VEGF). The regulatory effects of Egr-1 on TF under hypoxia were independent of HIF-1α. Either Egr-1 or HIF-1α was responsible for hypoxic induction of tumor cells adhesion. HIF-1α, but not Egr-1, had a pivotal role in human breast cancer cells invasion. Both Egr-1 and HIF-1α were critical to angiogenesis induced by hypoxic conditions in MDA-MB-231 and HUVEC co-cultures. In nude mice, both Egr-1 and HIF-1α small interfering RNA (siRNA) could decrease extravasation of MDA-MB-435 cells in the lung after tail vein injection.

CONCLUSIONS

Hypoxia-induced expression of TF in human breast cancer cells depends on Egr-1 and HIF-1α, and both of these proteins may play an important role in breast cancer metastasis, either directly or indirectly through the TF pathway.

EGFP-EGF1-conjugated PLGA nanoparticles for targeted delivery of siRNA into injured brain microvascular endothelial cells for efficient RNA interference

Injured endothelium is an important target for drug and/or gene therapy because brain microvascular endothelial cells (BMECs) play critical roles in various pathophysiological conditions. RNA-mediated gene silencing presents a new therapeutic approach for treating such diseases, but major challenge is to ensure minimal toxicity and target delivery of siRNA to injured BMECs. Injured BMECs overexpress tissue factor (TF), which the fusion protein EGFP-EGF1 could be targeted to. In this study, TNF alpha (TNF-α) was chosen as a stimulus for primary BMECs to produce injured endothelium in vitro. The EGFP-EGF1-PLGA nanoparticles (ENPs) with loaded TF-siRNA were used as a new carrier for targeted delivery to the injured BMECs. The nanoparticles then produced intracellular RNA interference against TF. We compared ENP-based transfections with NP-mediated transfections, and our studies show that the ENP-based transfections result in a more efficient downregulation of TF. Our findings also show that the TF siRNA-loaded ENPs had minimal toxicity, with almost 96% of the cells viable 24 h after transfection while Lipofectamine-based transfections resulted in only 75% of the cells. Therefore, ENP-based transfection could be used for efficient siRNA transfection to injured BMECs and for efficient RNA interference (RNAi). This transfection could serve as a potential treatment for diseases, such as stroke, atherosclerosis and cancer.

Clinical and prognostic significance of coagulation assays in melanoma

The activation of coagulation and fibrinolysis is frequently found among cancer patients. Such tumors are considered to be associated with a higher risk of invasion, metastases, and eventually worse outcome. The aim of this study is to explore the clinical and prognostic value of blood coagulation tests for melanoma patients. Pretreatment blood coagulation tests including prothrombin time (PT), activated partial thromboplastin time (APTT), prothrombin activity (PTA), international normalized ratio (INR), D-dimer (DD), fibrinogen (F) levels, and platelet (PLT) counts were carried out. This prospective study included 61 melanoma patients [stage I-II (n=10), stage III (n=14), stage IV (n=37), M1c (n=26) disease], and 50 healthy controls. It included 34 (56%) men, median age 53 years, range 16-88 years. Over half of the patients (54%) were in the metastatic stage and most of them (70%) had M1c. The plasma level of pretreatment blood coagulation tests including DD, F, APTT, INR levels, and PLT counts showed a statistically significant difference between the patient and the control group (P<0.001 for all, but P=0.049 for INR). The levels of INR, DD, F, and PLT counts were higher and APTT was lower in the melanoma group, whereas the PT and PTA levels did not show any significant difference. There was a significant association between PT, PTA, INR, and PLT levels and the age of the patient. Patients with node metastasis in M0 disease had higher levels of PTA and PLT counts (P=0.002 and 0.048, respectively) and lower levels of PT and INR (P=0.056 and 0.046, respectively). The M1c patients tended to have higher plasma F levels (437 vs. 297 mg/dl, P=0.055) than M1a and M1b patients. The 1-year survival rate for all patients was 70%. In association with distant metastasis, advanced metastatic stage (M1c), elevated lactate dehydrogenase, and erythrocyte sedimentation rate, only elevated plasma F levels had a significantly adverse effect on survival among the coagulation parameters (P=0.031). The 1-year survival rates for patients with high and normal F levels were 58 and 88%, respectively. In conclusion, changes in the coagulation-fibrinolytic system are often present in melanoma and elevation in the plasma F level is associated with decreased survival.

Microenvironment for cancer stem cells

Cancer stem cells and their metastatic niche are one of hot topics for tumor study. This review introduces the definition of microenvironment (niche) for cancer stem cells, related cells and factors, characteristics and regulation of niche, premetastatic niche and tissue components. The research progress in this field can provide some clues to the metastatic mechanism of tumors and the development and improvement of chemotherapeutic drugs.

Factor VII light chain-targeted lidamycin shows intensified therapeutic efficacy for liver cancer

The overexpression of tissue factor (TF) observed in numerous cancer cells and clinical samples of human cancers makes TF an ideal target for cancer therapy. The purpose of this study is to develop a TF-targeting energized fusion protein hlFVII-LDP-AE, which is composed of a human Factor VII light chain (hlFVII) as the targeting domain conjugated to the cytotoxic antibiotic lidamycin (LDM, LDP-AE) as the effector domain. The potential efficacy of hlFVII-LDP-AE for cancer therapy was tested in vitro by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assays and in vivo with a BALB/c nude mouse xenograft model of human liver cancer line HepG2. The inhibitory concentration (IC(50)) value of hlFVII-LDP-AE varied from 0.15 to 0.64 nM for the various human tumor lines. hlFVII-LDP-AE showed a tumor growth inhibition rate of 90.6% at the dose of 0.6 mg/kg in in vivo animal experiments. The mechanism through which hlFVII-LDP-AE inhibits tumor growth also was determined by Hoechst 33342 staining and Tdt-mediated dUTP nick-end labeling (TUNEL) assay. hlFVII-LDP-AE causes tumor cell death through inducing chromatin condensation and cleavage of genomic DNA. These findings suggest that the hlFVII-LDP-AE protocol is efficacious and tolerated in the mouse model of human liver cancer HepG2 and has clinical applicability for treating cancer patients.

Epigallocatechin-3-gallate inhibits proliferation and migration of human colon cancer SW620 cells in vitro

AIM

Epigallocatechin-3-gallate (EGCG) is the major polyphenolic constituent in green tea. The aim of this study is to investigate the effects of EGCG on proliferation and migration of the human colon cancer SW620 cells.

METHODS

Proliferation and migration of SW620 cells were induced by the protease-activated receptor 2-agonist peptide (PAR2-AP, 100 μmol/L) or factor VIIa (10 nmol/L), and analyzed using MTT and Transwell assays, respectively. The cellular cytoskeleton was stained with rhodamine-conjugated phalloidin and examined with a laser scanning confocal fluorescence microscope. The expression of caspase-7, tissue factor (TF) and matrix metalloproteinase (MMP)-9 in the cells was examined using QT-PCR, ELISA and Western blot assays. The activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and nuclear factor-kappa B (NF-κB) signaling pathways was analyzed with Western blot.

RESULTS

Both PAR2-AP and factor VIIa promoted SW620 cell proliferation and migration, and caused cytoskeleton reorganization (increased filopodia and pseudopodia). Pretreatment with EGCG (25, 50, 75, and 100 μg/mL) dose-dependently blocked the cell proliferation and migration induced by PAR2-AP or factor VIIa. EGCG (100 μg/mL) prevented the cytoskeleton changes induced by PAR2-AP or factor VIIa. EGCG (100 μg/mL) counteracted the down-regulation of caspase-7 expression and up-regulation of TF and MMP-9 expression in the cells treated with PAR2-AP or factor VIIa. Furthermore, it blocked the activation of ERK1/2 and NF-κB (p65/RelA) induced by PAR2-AP or factor VIIa.

CONCLUSION

EGCG blocks the proliferation and migration of SW620 cells induced by PAR2-AP and factor VIIa via inhibition of the ERK1/2 and NF-κB pathways. The compound may serve as a preventive and therapeutic agent for colon cancers.

Inhibition of the renin-angiotensin system downregulates tissue factor and vascular endothelial growth factor in human breast carcinoma cells

INTRODUCTION

The renin-angiotensin system (RAS) promotes angiogenesis and growth of neoplastic cells. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor AT1 blockers may protect against cancer. Tissue factor (TF), for its involvement in tumor growth, angiogenesis, and metastasis is considered a hallmark of cancer progression. In this study we evaluated whether RAS blockade modulates TF constitutive expression by the metastatic breast carcinoma MDA-MB-231 cell line.

MATERIALS AND METHODS

Cell TF activity was assessed by one stage clotting time, TF and VEGF antigens and mRNA levels by ELISA and RT-PCR, respectively. AT(1) was detected by flow-cytometry and angiotensin-II levels by EIA.

RESULTS

Captopril reduced in a concentration-dependent way both the strong constitutive TF activity (983.2±55.2 vs. 686.7±135.1U/5×10(5) cells with 10μg/ml captopril) and antigen (32.3±5.9 vs. 13.2±6.6ng/ml) in MDA-MB-231. Similar results were observed with enalapril. AT1 was present on cell membrane and losartan, a competitive inhibitor of AT1, reduced TF expression to a degree similar as that exerted by ACE inhibitors. Moreover, captopril and losartan downregulated the constitutive mRNA TF expression by ~35%. Similar results were observed with anti-AT1 and angiotensin II antibodies. In addition, the constitutive VEGF antigen and mRNA levels were reduced in the presence of captopril or losartan, and an anti-VEGF antibody downregulated cell TF activity by ~40%.

CONCLUSIONS

These results could, at least in part, contribute to the discussion about the possible effects of ACE inhibitors and AT1 receptor antagonists in malignancy, and offer new clues to support their use for tumor control.

Leptin upregulates tissue factor expression in human breast cancer MCF-7 cells

INTRODUCTION

Obesity is a risk factor for both cardiovascular disease and cancer development. Leptin, a cytokine produced by adipose tissue, controls different processes in peripheral tissues, including cancer development and thrombotic disorders in patients with a variety of clinical disorders. Tissue factor (TF), the trigger of blood clotting, is abundant in the adipose tissue. Since TF, often expressed by cancer cells, is considered a hallmark of cancer progression, we investigated whether leptin could modulate TF in the human metastatic breast carcinoma cell line MCF-7.

MATERIALS AND METHODS

MCF-7 cells were incubated with or without the different reagents at 37 °C. At the end of incubation, cells were tested for procoagulant activity by a one-stage clotting assay, TF and TNF-α antigen levels and mRNA by ELISA and real-time RT-PCR, respectively. Leptin receptor was studied by FACS.

RESULTS

Both TF activity and antigen constitutively expressed by MCF-7 were significantly increased by leptin in a dose-dependent fashion. TF mRNA levels were also enhanced indicating that leptin exerts its effect at the transcription level. The effect of leptin was specific and required binding to its receptor (Ob-R), which was found on the surface of the cells, since antibodies against leptin and Ob-R completely prevented TF expression upregulation. In addition, leptin enhanced both TNF-α mRNA synthesis and secretion from MCF7. An anti-TNF-α MoAb completely abolished the leptin-induced TF expression.

CONCLUSIONS

These data support the hypothesis that leptin, by its upregulation of TF, possibly mediated by TNF-α synthesis, may contribute to processes underlying both cancer and vascular cell disorders.

Deletion of the thrombin cleavage domain of osteopontin mediates breast cancer cell adhesion, proteolytic activity, tumorgenicity, and metastasis

BACKGROUND

Osteopontin (OPN) is a secreted phosphoprotein often overexpressed at high levels in the blood and primary tumors of breast cancer patients. OPN contains two integrin-binding sites and a thrombin cleavage domain located in close proximity to each other.

METHODS

To study the role of the thrombin cleavage site of OPN, MDA-MB-468 human breast cancer cells were stably transfected with either wildtype OPN (468-OPN), mutant OPN lacking the thrombin cleavage domain (468-ΔTC) or an empty vector (468-CON) and assessed for in vitro and in vivo functional differences in malignant/metastatic behavior.

RESULTS

All three cell lines were found to equivalently express thrombin, tissue factor, CD44, αvβ5 integrin and β1 integrin. Relative to 468-OPN and 468-CON cells, 468-ΔTC cells expressing OPN with a deleted thrombin cleavage domain demonstrated decreased cell adhesion (p < 0.001), decreased mRNA expression of MCAM, maspin and TRAIL (p < 0.01), and increased uPA expression and activity (p < 0.01) in vitro. Furthermore, injection of 468-ΔTC cells into the mammary fat pad of nude mice resulted in decreased primary tumor latency time (p < 0.01) and increased primary tumor growth and lymph node metastatic burden (p < 0.001) compared to 468-OPN and 468-CON cells.

CONCLUSIONS

The results presented here suggest that expression of thrombin-uncleavable OPN imparts an early tumor formation advantage as well as a metastatic advantage for breast cancer cells, possibly due to increased proteolytic activity and decreased adhesion and apoptosis. Clarification of the mechanisms responsible for these observations and the translation of this knowledge into the clinic could ultimately provide new therapeutic opportunities for combating breast cancer.

The role of microvesicles in malignancies

Microvesicles are membrane-covered cell fragments whose size varies between 30 and 1,000 nm. They are generated by all cell types, constituvely and in response to activation signals. Their importance in intercellular communication has been only recently discovered. They seem to enhance the potential of information transfer between cells, displaying a large number of proteins and lipids as membrane constituents and as components of the inner vesicular content. The content reflects the phenotype of the donor cell and allows the identification of the microvesicular origine as well. Complex "packets" of molecules are transmitted to the target cells this way, modifying their cellular physiology. Additionally, epigenetic changes may be induced by transmitted DNA and RNAs, that have also been identified in these vesicles. The vesicles can act in close and far distances as well. Microvesicles have been implicated in several physiological and pathological processes. There is an increasing evidence, that they play a pivotal role in tumorigenesis. Vesicles shedding from tumor cells reflect the special potential of the tumor for survival and expansion, independently from cell-to-cell contact. Tumor derived vesicles are fully equipped to facilitate the escape of tumor cells from immune surveillance through their protein and RNA content, at the same time they are involved in the establishment of an optimal environment for newly formed and metastatic tumor cells, influencing angiogenesis and the reorganization of the extracellular matrix. As immune cells, endothels, platelets and stem cells also release microvesicles, a multilevel communication network draws up, allowing a complex interplay between the cells. The concentration of tumor derived vesicles increases in blood plasma and other body fluids with the progression of the disease; therefor they may serve as prognostic markers. The microvesicular approach can offer new perspectives: interfering with the formation, release and propagation of these vesicles, they can be considered as new targets in tumor therapy.

The saponin monomer of dwarf lilyturf tuber, DT-13, reduces human breast cancer cell adhesion and migration during hypoxia via regulation of tissue factor

Adhesion and migration of tumor cells are crucial steps in tumor invasion and metastasis. In the present study, we investigated the effects of saponin monomer 13 of dwarf lilyturf tuber (DT-13) on metastasis of human breast cancer cells (MDA-MB-435) during hypoxia. The effects and molecular mechanisms of DT-13 on MDA-MB-435 cells metastatic phenotype in vitro and in vivo were evaluated by RNA interference; quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assays. DT-13 had no significant effects on cell adhesion and migration under normoxia conditions. Under hypoxic conditions, MDA-MB-435 adhesion to vitronectin was inhibited by about 43.5% or 60.8% after exposure of the cells to DT-13 at 1 microM or 10 microM, respectively. DT-13 decreased the migratory response by hypoxia at 1 or 10 microM, and inhibition ratios were 20% and 30%, respectively. DT-13 inhibited hypoxia-induced expression of alphavbeta3 integrin, tissue factor (TF) and early growth response gene-1 (Egr-1) and decreased excretion of matrix metalloproteinase 9 (MMP-9) of MDA-MB-435 cells under hypoxic conditions. After Egr-1 short interference RNA (siRNA) treatment, DT-13 could still inhibit the up-regulation of TF mRNA and protein levels and its pro-coagulant activity (PCA) under hypoxia. In nude mice, DT-13 decreased extravasation of MDA-MB-435 cells in the lung after tail vein injection. Our data suggest that DT-13 inhibits MDA-MB-435 cells metastasis during hypoxia via regulation of TF, and the effect of DT-13 on TF is partly mediated by Egr-1.

Binding of anti-GRP78 autoantibodies to cell surface GRP78 increases tissue factor procoagulant activity via the release of calcium from endoplasmic reticulum stores

The increased risk of venous thromboembolism in cancer patients has been attributed to enhanced tissue factor (TF) procoagulant activity (PCA) on the surface of cancer cells. Recent studies have shown that TF PCA can be modulated by GRP78, an endoplasmic reticulum (ER)-resident molecular chaperone. In this study, we investigated the role of cell surface GRP78 in modulating TF PCA in several human cancer cell lines. Although both GRP78 and TF are present on the cell surface of cancer cells, there was no evidence of a stable interaction between recombinant human GRP78 and TF, nor was there any effect of exogenously added recombinant GRP78 on cell surface TF PCA. Treatment of cells with the ER stress-inducing agent thapsigargin, an inhibitor of the sarco(endo)plasmic reticulum Ca(2+) pump that causes Ca(2+) efflux from ER stores, increased cytosolic [Ca(2+)] and induced TF PCA. Consistent with these findings, anti-GRP78 autoantibodies that were isolated from the serum of patients with prostate cancer and bind to a specific N-terminal epitope (Leu(98)-Leu(115)) on cell surface GRP78, caused a dose-dependent increase in cytosolic [Ca(2+)] and enhanced TF PCA. The ability to interfere with cell surface GRP78 binding, block phospholipase C activity, sequester ER Ca(2+), or prevent plasma membrane phosphatidylserine exposure resulted in a significant decrease in the TF PCA induced by anti-GRP78 autoantibodies. Taken together, these findings provide evidence that engagement of the anti-GRP78 autoantibodies with cell surface GRP78 increases TF PCA through a mechanism that involves the release of Ca(2+) from ER stores. Furthermore, blocking GRP78 signaling on the surface of cancer cells attenuates TF PCA and has the potential to reduce the risk of cancer-related venous thromboembolism.

Thrombin regulates the metastatic potential of human rhabdomyosarcoma cells: distinct role of PAR1 and PAR3 signaling

We observed that human rhabdomyosarcoma (RMS) cells highly express a tissue factor that promotes thrombin formation, which indirectly and directly affects RMS progression. First, we found that thrombin activates platelets to generate microvesicles (PMV), which transfer to RMS cells' alpha2beta3 integrin and increase their adhesiveness to endothelial cells. Accordingly, RMS cells covered with PMVs showed higher metastatic potential after i.v. injection into immunodeficient mice. Furthermore, PMVs activate mitogen-activated protein kinase (MAPK)p42/44 and AKT to chemoattract RMS cells. We also found that RMS cells express functional protease-activated receptor-1 (PAR1) and PAR3 and respond to thrombin stimulation by MAPKp42/44 and MAPKp38 phosphorylation. To our surprise, thrombin did not affect RMS proliferation or survival; it inhibited the chemotactic and adhesive properties of RMS cells. However, when PAR1-specific agonist thrombin receptor-activating peptide 6 was used, which does not activate PAR3, selective PAR1 stimulation enhanced RMS proliferation. To learn more on the role of PAR1 and PAR3 antagonism in RMS proliferation and metastasis, we knocked down both receptors by using a short hairpin RNA strategy. We found that although thrombin does not affect growth of PAR1(-/-) cells, it stimulated the proliferation of PAR3(-/-) cells. More importantly, PAR3(-/-) cells, in contrast to PAR1(-/-) ones, formed larger tumors in immunodeficient mice. We conclude that thrombin is a novel underappreciated modulator of RMS metastasis and that we have identified a novel role for PAR3 in thrombin signaling.

Instructive role of the vascular niche in promoting tumour growth and tissue repair by angiocrine factors

The precise mechanisms whereby anti-angiogenesis therapy blocks tumour growth or causes vascular toxicity are unknown. We propose that endothelial cells establish a vascular niche that promotes tumour growth and tissue repair not only by delivering nutrients and O2 but also through an 'angiocrine' mechanism by producing stem and progenitor cell-active trophogens. Identification of endothelial-derived instructive angiocrine factors will allow direct tumour targeting, while diminishing the unwanted side effects associated with the use of anti-angiogenic agents.