The biology and tumour-related properties of monocyte tissue factor

Tofacitinib Affects M1-like and M2-like Polarization and Tissue Factor Expression in Macrophages of Healthy Donors and IBD Patients

BACKGROUND

Tofacitinib, as inhibitor of Janus kinases (JAK), interrupts the transmission of numerous pro-inflammatory cytokines involved in the pathogenesis of inflammatory bowel diseases (IBD). Therefore, tofacitinib provides a potent option to treat ulcerative colitis (UC). Besides the anti-inflammatory potential, inhibition of widespread JAKs carries the risk of side effects. Macrophages are involved in the form of different subtypes in inflammation, wound healing, and even coagulation. This study aimed to explore the balanced use of tofacitinib in M1-like as well as M2-like macrophages of healthy donors and patients with IBD.

METHODS

Monocytes of healthy donors and patients with chronic courses of IBD were obtained from blood samples. Macrophage colony-stimulating factor (M-CSF)-derived macrophages were treated with tofacitinib (1 µM, 5 µM, 10 µM) and polarized with either lipopolysaccharide and interferon (IFN)-γ towards M1-like-phenotype or with interleukin (IL)-4 towards M2-like-phenotype. ELISA and flow cytometry were used to evaluate cytokine levels and surface molecules.

RESULTS

Tofacitinib had a modulating effect on M1-like macrophages whereby the effect on pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, IL-12, IL-23) was less pronounced than the induction of anti-inflammatory IL-10. However, during M2-like polarization tofacitinib impaired the development of the corresponding phenotype becoming evident through decreased IL-10 levels and CD206 expression in treated macrophages. In both phenotypes, tofacitinib strongly downregulated the expression of immunostimulatory molecules (CD80, CD86, CD83, CD40). Furthermore, a dose-dependent correlation between treatment with tofacitinib and expressed tissue factor was noticed.

CONCLUSIONS

Tofacitinib influences both polarizations (M1/M2) and the expression of tissue factor in a dose-dependent manner.

Tissue factor overexpression in triple-negative breast cancer promotes immune evasion by impeding T-cell infiltration and effector function

Triple-negative breast cancer (TNBC) remains a most deadly human malignancy with limited response to chemotherapy, targeted therapy and immunotherapy. Tumor immunoenvironment plays an increasingly important role in therapy outcome. Tissue factor (TF) is the target of the FDA-approved ADC Tivdak. HuSC1-39 is the parent antibody of MRG004A, a clinical stage TF-ADC (NCT04843709). Here, we employed HuSC1-39 (termed "anti-TF") to investigate the role of TF in regulating immune-tolerance in TNBC. We found that patients with aberrant TF expression had a poor prognosis and low immune effector cell infiltration, characterizing as "cold tumor". In the 4T1 TNBC syngeneic mouse model, knockout of tumor cell TF inhibited tumor growth and increased tumor infiltration of effector T cell, which was not dependent on the clotting inhibition. In an immune-reconstituted M-NSG mouse model of TNBC, anti-TF inhibited tumor growth, which was further enhanced by a dual-targeting anti-TF&TGFβR fusion protein. There were diminished P-AKT and P-ERK signaling and profound tumor cell death in treated tumors. Transcriptome analyses and immunohistochemistry revealed a dramatically improved tumor immunoenvironment including the increase of effector T cells, decrease of Treg cells and the transformation of tumor into "hot tumor". Moreover, employing qPCR analysis and T cell culture, we further demonstrated that TF expression in tumor cells is sufficient to block the synthesis and secretion of T cell-recruiting chemokine CXCL9/10/11. Treatment of TF-high TNBC cells with anti-TF or TF-knockout all stimulated CXCL9/10/11 production, promoted T cell migration and effector function. Thus, we have identified a new mechanism of TF in TNBC tumor progression and therapy resistance.

Systematic study of tissue factor expression in solid tumors

BACKGROUND

Elevated tissue factor (TF) expression, although restricted in normal tissue, has been reported in multiple solid cancers, and expression has been associated with poor prognosis. This manuscript compares TF expression across various solid tumor types via immunohistochemistry in a single study, which has not been performed previously.

AIMS

To increase insight in the prevalence and cellular localization of TF expression across solid cancer types, we performed a detailed and systematic analysis of TF expression in tumor tissue obtained from patients with ovarian, esophageal, bladder, cervical, endometrial, pancreatic, prostate, colon, breast, non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), and glioblastoma. The spatial and temporal variation of TF expression was analyzed over time and upon disease progression in patient-matched biopsies taken at different timepoints. In addition, TF expression in patient-matched primary tumor and metastatic lesions was also analyzed.

METHODS AND RESULTS

TF expression was detected via immunohistochemistry (IHC) using a validated TF-specific antibody. TF was expressed in all cancer types tested, with highest prevalence in pancreatic cancer, cervical cancer, colon cancer, glioblastoma, HNSCC, and NSCLC, and lowest in breast cancer. Staining was predominantly membranous in pancreatic, cervical, and HNSCC, and cytoplasmic in glioblastoma and bladder cancer. In general, expression was consistent between biopsies obtained from the same patient over time, although variability was observed for individual patients. NSCLC biopsies of primary tumor and matched lymph node metastases showed no clear difference in TF expression overall, although individual patient changes were observed.

CONCLUSION

This study shows that TF is expressed across a broad range of solid cancer types, and expression is present upon tumor dissemination and over the course of treatment.

Tissue Factor Expression in Colorectal Adenocarcinoma: Association with Angiogenesis and Clinical and Pathological Aspects

Introduction Tissue factor (TF) expression has been described in various neoplasms and was correlated with angiogenesis and metastases.

Objectives To describe TF expression in colorectal cancers, correlating it with microvessel density and clinical and pathological variables.

Methods Immunohistochemistry was used to determine TF expression and microvessel density. The Student t-test was used to compare high and low TF expression with microvessel density and with age. The chi-squared test was used for other comparisons, and Kaplan-Meier curves were used for survival analyses.

Results Forty-three patients were operated with curative intent. Their mean age was 58.1 ± 12.6 years old, and 62.8% were male. The rectum was the most common location (60,4%), and most tumors reached the serosa and peri-intestinal fat (72.1%). Lymph nodes were positive in 46.5%, and 72.1% of the tumors were moderately differentiated adenocarcinomas. Death occurred in 27.6 ± 12.8 months in 51.1% of the patients who had recurrence. Tissue factor expression was intense in 88.4%. There was a positive correlation between TF expression and microvessel density (p = 0.02), and between TF and older age (p < 0.01). There was no correlation between TF expression and other variables (gender, histological type, penetration into the intestinal wall, and lymphatic and systemic metastases). Tissue factor expression did not correlate with survival.

Conclusion Tissue factor expression correlated with increased microvessel density and older age. Further studies are necessary to ascertain the clinical relevance of TF in colorectal cancer.

Contribution of allosteric disulfide in the structural regulation of membrane-bound tissue factor-factor VIIa binary complex

Two distinct populations, active and cryptic forms of tissue factor (TF), reside on the cell surface. Apart from phospholipid contribution, various models have been introduced to explain decryption/encryption of TF. The proposed model, the switching of Cys186-Cys209 bond of TF, has become the matter of controversy. However, it is well accepted that this disulfide has an immense influence upon ligand factor VIIa (FVIIa) for its binding. However, molecular level understanding for this remains unveiled due to lack of detailed structural information. In this regard, we have performed the molecular dynamic study of membrane-bound TF/TF-FVIIa in both the forms (±Cys186-Cys209 allosteric disulfide bond), individually. Dynamic study depicts that disulfide bond provides structural rigidity of TF in both free and ligand-bound forms. This disulfide bond also governs the conformation of FVIIa structure as well as the binding affinity of FVIIa toward TF. Significant differences in lipid-protein interaction profiles of both the forms of TF in the complex were observed. Two forms of TF, oxidized and reduced, have different structural conformation and behave differentially toward its ligand FVIIa. This disulfide bond not only alters the conformation of GLA domain of FVIIa in the vicinity but allosterically regulates the conformation of the distantly located FVIIa protease domain. We suggest that the redox status of the disulfide bond also governs the lipid-mediated interactions with both TF and FVIIa. Communicated by Ramaswamy H. Sarma.

Differential ability of tissue factor antibody clones on detection of tissue factor in blood cells and microparticles

INTRODUCTION

Tissue factor (TF), the primary initiator of coagulation in vivo, plays a major role in both thrombosis and hemostasis. The expression of TF in monocytes is well documented, but its presence in other blood cells has been disputed, possibly due to methodological variations among different studies.

MATERIALS AND METHODS

We studied TF expression on platelets, monocytes, lymphocytes and microparticles (MPs) by flow cytometry (FCM) with five commercially available mouse anti-human TF antibodies (HTF-1, TF9-10H10, CLB/TF-5, VIC7 and VD8). The ability of different TF antibodies to inhibit cell surface TF activity was explored by incubating LPS-stimulated monocytes and MPs derived from LPS-stimulated monocytes (MMPs) with TF antibodies followed by measuring TF activity.

RESULTS

HTF-1 detected TF only on LPS-stimulated monocytes, whereas, TF9-10H10 and VD8 detected TF associated with MPs and MMPs in addition to LPS stimulated monocytes. Surprisingly, CLB/TF-5 and VIC7 detected TF on platelets, monocytes even under unstimulated conditions, in addition to MPs and MMPs. CLB/TF-5 also detected TF on unstimulated lymphocytes. Inhibitory studies showed that at a final concentration of 10 μg/mL, HTF-1, CLB/TF-5 and VD8 inhibited monocyte TF activity by 81-84% and MMP TF activity by 92-96%; whereas TF9-10H10 had no inhibitory effect on TF activity in monocytes and MMPs.

CONCLUSIONS

Our results suggest non-specific binding by the CLB/TF-5 and VIC7 antibodies in a FCM test system and explain at least some of the reports on TF presence in blood cells, particularly TF associated with platelets and MPs. TF9-10H10 and VD8 are more suitable to detect TF on MPs by FCM.

Arterial and venous thrombosis in cancer patients

The most frequent ultimate cause of death is myocardial arrest. In many cases this is due to myocardial hypoxia, generally arising from failure of the coronary macro- and microcirculation to deliver enough oxygenated red cells to the cardiomyocytes. The principle reason for this is occlusive thrombosis, either by isolated circulating thrombi, or by rupture of upstream plaque. However, an additionally serious pathology causing potentially fatal stress to the heart is extra-cardiac disease, such as pulmonary hypertension. A primary cause of the latter is pulmonary embolus, considered to be a venous thromboembolism. Whilst the thrombotic scenario has for decades been the dominating paradigm in cardiovascular disease, these issues have, until recently, been infrequently considered in cancer. However, there is now a developing view that cancer is also a thrombotic disease, and notably a disease predominantly of the venous circulation, manifesting as deep vein thrombosis and pulmonary embolism. Indeed, for many, a venous thromboembolism is one of the first symptoms of a developing cancer. Furthermore, many of the standard chemotherapies in cancer are prothrombotic. Accordingly, thromboprophylaxis in cancer with heparins or oral anticoagulation (such as Warfarin), especially in high risk groups (such as those who are immobile and on high dose chemotherapy), may be an important therapy. The objective of this communication is to summarise current views on the epidemiology and pathophysiology of arterial and venous thrombosis in cancer.

Tissue factor in tumour progression

The linkage between activation of the coagulation system and cancer is well established, as is deregulation of tissue factor (TF) by cancer cells, their vascular stroma and cancer-associated inflammatory cells. TF is no longer perceived as an 'alternative' coagulation factor, but rather as a central trigger of the coagulation cascade and an important cell-associated signalling receptor activated by factor VIIa, and interacting with several other regulatory entities, most notably protease-activated receptors (PAR-1 and PAR-2). Preclinical studies revealed the role of oncogenic transformation and tumour micro-environment as TF regulators in cancer, along with the impact of this receptor on gene expression, tumour growth, metastasis, angiogenesis and, possibly, formation of the cancer stem cell niche. Increasing interest surrounds the shedding of TF-containing microvesicles from cancer cells, their entry into the circulation and their role in the intercellular transfer of TF activity, cancer coagulopathy and other processes. Recent data also suggest differential roles of cell autonomous versus global effects of TF in various settings. Questions are raised regarding the consequences of TF expression by tumour cells themselves and by their associated host stroma. Progress in these areas may soon begin to impact on clinical practice and, as such, raises several important questions. Can TF be exploited as a therapeutic target in cancer? Where and when may this be safe and beneficial? Is expression of TF in various disease settings useful as a biomarker of cancer progression or the associated hypercoagulability? What clinical questions related to TF are especially worthy of further exploration, at present and in the near future? Some of these developments and questions will be discussed in this chapter.

Paclitaxel downregulates tissue factor in cancer and host tumour-associated cells

Paclitaxel, a microtubule-stabilising compound with potent anti-tumour activity, has been clinically used in a wide variety of malignancies. Tissue factor (TF) is often expressed by tumour-associated endothelial and inflammatory cells, as well as by cancer cells themselves, and it is considered a hallmark of cancer progression. We investigated whether paclitaxel could modulate TF in human mononuclear (MN) cells, human umbilical vein endothelial cells (HUVEC) and the metastatic breast carcinoma cell line MDA-MB-231. Cells were incubated with or without paclitaxel at 37 degrees C. At the end of incubation, cells were disrupted and tested for procoagulant activity by a one-stage clotting assay, for TF antigen levels by ELISA and TF mRNA by real-time RT-PCR. IL-6 and IL-1beta were tested by ELISA in conditioned medium. Both the strong TF activity and antigen constitutively expressed by MDA-MB-231 and the TF induced by LPS, TNF-alpha and IL-1beta in MN cells and HUVEC were significantly reduced by paclitaxel. In the presence of paclitaxel, lower TF mRNA levels were also detected. Since paclitaxel has been shown to induce the expression of inflammatory genes in monocytes and tumour cells, we tested whether paclitaxel could influence IL-6 and IL-1beta release from the cells used in this paper. Neither the constitutive expression of IL-6 and IL-1beta by MDA-MB-231 nor the basal and LPS-induced release from MN cells and HUVEC was affected. Our data support the hypothesis that the anti-tumour effects of paclitaxel may, at least in part, be mediated by the capacity of this drug to modulate the procoagulant potential of cancer and host cells.

Vascular determinants of cancer stem cell dormancy--do age and coagulation system play a role?

The inability of tumour-initiating cancer stem cells (CSCs) to bring about a net increase in tumour mass could be described as a source of tumour dormancy. While CSCs may be intrinsically capable of driving malignant growth, to do so they require compatible surroundings of supportive cells, growth factors, adhesion molecules and energy sources (e.g. glucose and oxygen), all of which constitute what may be referred to as a 'permissive' CSC niche. However, in some circumstances, the configuration of these factors could be incompatible with CSC growth (a 'non-permissive' niche) and lead to their death or dormancy. CSCs and their niches may also differ between adult and paediatric cancers. In this regard the various facets of the tumour-vascular interface could serve as elements of the CSC niche. Indeed, transformed cells with an increased tumour-initiating capability may preferentially reside in specific zones adjacent to tumour blood vessels, or alternatively originate from poorly perfused and hypoxic areas, to which they have adapted. CSCs themselves may produce increased amounts of angiogenic factors, or rely for this on their progeny or activated host stromal cells. It is likely that 'vascular' properties of tumour-initiating cells and those of their niches may diversify and evolve with tumour progression. The emerging themes in this area include the role of vascular (and bone marrow) aging, vascular and metabolic comorbidities (e.g. atherosclerosis) and the effects of the coagulation system (both at the local and systemic levels), all of which could impact the functionality of CSCs and their niches and affect tumour growth, dormancy and formation of occult as well as overt metastases. In this article we will discuss some of the vascular properties of CSCs relevant to tumour dormancy and progression, including: (i) the role of CSCs in regulating tumour vascular supply, i.e the onset and maintenance of tumour angiogenesis; (ii) the consequences of changing vascular demand (vascular dependence) of CSC and their progeny; (iii) the interplay between CSCs and the vascular system during the process of metastasis, and especially (iv) the impact of the coagulation system on the properties of CSC and their niches. We will use the oncogene-driven expression of tissue factor (TF) in cancer cells as a paradigm in this regard, as TF represents a common denominator of several vascular processes that commonly occur in cancer, most notably coagulation and angiogenesis. In so doing we will explore the therapeutic implications of targeting TF and the coagulation system to modulate the dynamics of tumour growth and tumour dormancy.

Tissue factor in cancer

PURPOSE OF REVIEW

Tissue factor is increasingly viewed as an integral part of the vicious circle that links the vascular system with cancer progression at multiple systemic, cellular and molecular levels.

RECENT FINDINGS

The emerging tenet in this area is that oncogenic events/pathways driving the malignant process also stimulate the expression of tissue factor by cancer cells and promote the release of tissue factor-containing microvesicles into the circulation. The combined effects of these changes likely contribute to cancer coagulopathy, cessation of tumour dormancy, aggressive growth, angiogenesis and metastasis, notably through a combination of procoagulant and signalling effects set in motion by tissue factor. As certain tumour-associated host cell types (inflammatory cells, endothelium) may also express tissue factor their contribution is plausible, though poorly understood. Interestingly, tissue factor could be 'shared' between various subsets of cancer and host cells due to intercellular transfer of tissue factor-containing microvesicles. It has recently been proposed that tissue factor may influence the interactions between tumour initiating (stem) cells and their growth or prometastatic niches.

SUMMARY

Whereas targeting tissue factor in cancer is appealing, the prospects in this regard will depend on the identification of disease specific indications, active agents and their safe regimens.

Tissue factor pathway inhibitor: structure, biology and involvement in disease

Tissue factor (TF)-initiated coagulation plays a significant role in the pathophysiology of many diseases, including cancer and inflammation. Tissue factor pathway inhibitor (TFPI) is a plasma Kunitz-type serine protease inhibitor, which modulates initiations of coagulation induced by TF. In a factor (F) Xa-dependent feedback system, TFPI binds directly and inhibits the TF-FVII/FVIIa complex. Normally, TFPI exists in plasma both as a full-length molecule and as variably carboxy-terminal truncated forms. TFPI also circulates in complex with plasma lipoproteins. The levels and the dual inhibitor effect of TFPI on FXa and TF-FVII/FVIIa complex offers insight into the mechanisms of various pathological conditions triggered by TF. The use of selective pharmacological inhibitors has become an indispensable tool in experimental haemostasis and thrombosis research. In vivo administration of recombinant TFPI (rTFPI) in an experimental animal model prevents thrombosis (and re-thrombosis after thrombolysis), reduces mortality from E. coli-induced-septic shock, prevents fibrin deposition on subendothelial human matrix and protects against disseminated intravascular coagulation (DIC). Thus, TFPI may play an important role in modulating TF-induced thrombogenesis and it may also provide a unique therapeutic approach for prophylaxis and/or treatment of various diseases. In this review, we consider structural and biochemical aspects of the TFPI molecule and detail its inhibitory mechanisms and therapeutic implications in various disease conditions.

Seminal tissue factor revisited

Studies of seminal tissue factor (TF) are few and mostly based on small numbers. Due to the reported lack of factor (F) X in semen, it has been suggested that TF may not have a role in seminal coagulum formation. However, recent identification of a number of haemostatic factors in semen justifies a re-evaluation of its occurrence. Semen specimens were collected from sub-fertile (n = 19), normally fertile (n = 33), semen donors (n = 30) and vasectomized subjects (n = 62), some fractionated into sperm, a prostasome-rich fraction and seminal plasma. Functional and antigenic TF levels were measured and related to conventional fertility parameters. Semen contains high concentration of functional and antigenic TF. Most TF was found in seminal plasma prepared by low-speed centrifugation. When further fractionated by ultracentrifugation much of this may reside in the pellet (prostasomal fraction). It was also detectable on sperm. TF antigen levels were higher in vasectomized subjects than sub-fertile, normally fertile, donor (p = 0.02) and a 'pooled normal semen parameters' (PNSP) stratification (derived from a combination of measurements) (p = 0.06). The sub-fertile group showed a wider variation than normal, donor or the PNSP subjects. Seminal TF antigen levels correlated significantly with sperm agglutination (p = 0.03) and abnormal sperm morphology (p = 0.04). Subjects with anti-sperm antibodies also showed high TF antigen levels. In conclusion, semen contains functional and antigenic TF at high concentrations. A full complement of clotting factors probably exists in semen, so some pro-coagulant role for TF should not be excluded. Decreased seminal TF levels appear to be associated with seminal parameters that are known to favour male fertility.

Angiotensin II induces the expression of tissue factor and its mechanism in human monocytes

The renin-angiotensin system (RAS) is linked with the vascular motion and the secretion of aldosterone. The purpose of the present study was to elucidate whether angiotensin II (Ang II) induces monocytes (Mo) to express tissue factor (TF) and if Ang II subtype 1 receptor (AT1R) antagonists inhibit the effect of Ang II. The roles of different intracellular signal transduction pathways and IkappaB/NF-kappaB in Ang II-induced TF expression of Mo were also studied to explore the mechanisms involved. Mo were isolated from heparinized human blood by a two-step gradient centrifugation, cultured in RPMI-1640 and exposed to Ang II and other test reagents. Mo TF activity and TF antigen were determined with a one-stage clotting method and ELISA, respectively, after the culture. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the TF mRNA levels in Mo. The level of IkappaBalpha in Mo was detected by Western blot analysis. Electrophoresis mobility shift assay (EMSA) was performed to evaluate the binding activity of NF-kappaB in Mo. The experiment results are as follows: (1) Ang II (10(-10)-10(-7) M) induced Mo to express TF activity but had no marked effect on other mononuclear cells. Ang II 10(-10)-10(-7) M) also caused increased TF mRNA expression and TF antigen from Mo in a dose-dependent manner. The TF antigen of Mo was elevated at 4 h after Mo was exposed to Ang II (10(-7) M) in culture, reached the peak at 6 h, and then declined from 12 h. The changes of TF activity were positively correlated with those of TF antigen. TF mRNA expression was elevated at 1 h, peaked at 3 h, and declined after 8 h. (2) Losartan (10(-6)-10(-5) M) significantly inhibited the stimulative effects of Ang II on TF activity, TF antigen and TF mRNA in Mo in a dose-dependent manner. (3) The protein kinase C (PKC) inhibitor, staurosporine, and the protein tyrosine kinase (PTK) inhibitor, genistein, both lowered TF levels in Mo, but the inhibitory effect of staurosporine was stronger than that of genistein. The effect of mitogen-activated protein kinase (MAPK) inhibitor, U0126, on monocytic TF expression was not significant. (4) Western blot analysis revealed that after Ang II (10(-7) M)exposure, levels of IkappaBalpha began to decrease at 15 min, reached a nadir at 60 min (P<.01), and recovered at 180 min. (5) EMSA showed that NF-kappaB binding activity started to increase at 15 min, reached a peak at 60 min, and returned to baseline at 180 min. The present data suggest that Ang II can directly induce TF expression in human Mo and this effect is mediated by AT1R. PKC may play the most important role in Ang II-induced TF expression among the three signal pathways detected. In addition, activation of NF-kappaB is also involved in the TF expression of Mo induced by Ang II.

Studies on rabbit natural and recombinant tissue factors: intracellular retention and regulation of surface expression in cultured cells

Tissue factor (TF) is the most important trigger of blood coagulation in vascular pathology. Rabbit TF, with or without (ΔC) its COOH-terminal intracellular tail, has been conjugated to green fluorescent protein (GFP) to study subcellular localization and other functions of TF. TF-GFP and TFΔC-GFP are associated with Na2CO3-resistant buoyant fractions in HEK-293 cells (lipid rafts); there is no morphological difference in the surface distribution of these or other GFP-labeled membrane proteins present in or excluded from rafts (confocal microscopy, HEK-293 cells). Endogenous TF expressed by rabbit aortic smooth muscle cells (SMCs) is also raft associated. Membranes from HEK-293 cells expressing recombinant TF-GFP or wild-type TF were equipotent to clot human plasma; however, TFΔC-GFP was ∼20-fold more active (per membrane weight). Immunoblot confirmed that the deletion mutant is more abundantly expressed, and confocal microscopy showed that it has preferential membrane localization, whereas TF-GFP is mainly intracellular (nuclear lining and multiple granules). With a similar half-life (<4 h), the two constructions differ by their intracellular retention, lower for TFΔC-GFP. In serum-starved SMCs, the expression of endogenous TF was upregulated by interleukin-1β and/or FBS treatment (immunoblot, immunofluorescence, clotting assay). However, TF secretion or surface expression was not regulated by stimuli of physiological intensity (such as stimulation of the coexpressed kinin B1receptors), although a calcium ionophore was highly active in this respect. TF is a raft-associated molecule whose surface expression (secretion) is apparently retarded or impaired by structural determinant(s) located in its COOH-terminal tail.

Haemostatic alterations in colorectal cancer: perspectives for future treatment

The role of the haemostatic system in colorectal cancer (CRC) is reviewed. Correlations between the activation of the haemostatic system and overall survival have been suggested. Experimental studies indicate that the haemostatic system plays a key role in growth, invasion and dissemination of tumour cells, and in tumour related angiogenesis. Additional activation by the surgical trauma and postoperative infections are discussed. Finally, anti-cancer modalities directed against regulation of the haemostatic system in CRC are considered.

A quantitative real-time PCR method for tissue factor mRNA

BACKGROUND

Tissue factor (TF) is primarily known for its function to initiate blood coagulation. The range of in vivo expression of TF is wide and requires a dynamic assay for monitoring. A general method for TF mRNA quantitation that is dynamic, sensitive and applicable to a variety of experimental systems or clinical situations is therefore desirable.

OBJECTIVES

To develop a method for sensitive and dynamic quantitation of TF mRNA in human blood cells.

METHODS

TF mRNA expression was analysed and evaluated in monocyte isolations, in whole blood (healthy volunteers and patients scheduled for percutaneous coronary intervention, PCI) and in a panel of human cell lines. RNA was extracted, reverse transcribed and subjected to real-time PCR amplification, according to the TaqMan technology. A TF plasmid was constructed as calibrator of the assay. Two housekeeping genes used as endogenous controls for cDNA quality and integrity were evaluated.

RESULTS

The assay was linear by seven orders of magnitude and detected down to 10(2) copies of the TF plasmid. The coefficient of variation was 4% intra-assay and 28% between the assays when using beta2MG as endogenous control. The beta-actin gene expression was induced by treatment with lipopolysaccharide (LPS) in blood leukocytes and could not be used as an endogenous control. However, beta2MG showed only minor variations upon treatment with LPS. The TF mRNA and antigen expression, measured in a Western blot, correlated well (R(2)=0.903) in a panel of 11 human cell lines.

CONCLUSIONS

We have established a method for sensitive and dynamic quantitation of TF mRNA in experimental systems and for clinical situations.

The role of tissue factor in colorectal cancer

The possible role of tissue factor (TF) in colorectal cancer (CRC) is reviewed. A correlation between TF expression and advanced stages of malignancy, and a correlation between TF expression and overall survival have been suggested in CRC. This is supported by experimental studies indicating that TF plays a key role in growth, invasion and dissemination of tumour cells, and in tumour related angiogenesis as well. In addition, the activation of TF in CRC patients in relation to the surgical trauma, perioperative blood transfusion and development of postoperative bacterial infectious complications are discussed. Finally, future directions for the development of anticancer modalities directed against regulation of TF are considered.

Tumoral angiogenesis and tissue factor expression during hepatocellular carcinoma progression in a transgenic mouse model

BACKGROUND/AIMS

The hypervascularity described in hepatocellular carcinoma varies according to the progression and the differentiation of the tumor, suggesting an angiogenic switch during tumor development.

METHODS

We used a transgenic mouse model of hepatocellular carcinoma induced by the expression of SV40-T antigen, in which male mice developed hepatic tumors at various temporal and histological stages, whereas female mice remained tumor-free. We analyzed, by immunostaining and reverse transcription-polymerase chain reaction, factors involved in tumoral angiogenesis.

RESULTS

We demonstrated that tumoral angiogenesis occurred before the development of diffuse hepatocarcinoma. We showed that some SV40-T-positive cells with an endothelial phenotype are involved in angiogenic processes, suggesting a partial vasculogenic mimicry. This tumoral angiogenesis is associated with platelet activation due to tissue factor expression in endothelial cells and invading macrophages. Normal and transgenic livers exhibited different pattern of expression of hypoxia-inducible factor 1 alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) mRNA.

CONCLUSIONS

This model of hepatocellular carcinoma displays marked tumoral angiogenesis, with proliferation, remodeling and arterialization of hepatic sinusoids, probably associated with a partial vasculogenic mimicry. Abnormal angiogenesis observed in hepatocarcinoma was associated with platelet activation by tissue factor (TF) produced by endothelial cells and invading macrophages. In this transgenic model, HIF-1alpha, VEGF, and TF play a crucial role in tumoral angiogenesis.

NCX-4016 (NO-aspirin) inhibits lipopolysaccharide-induced tissue factor expression in vivo: role of nitric oxide

BACKGROUND

NCX-4016 is an acetylsalicylic acid (ASA) derivative containing a nitric oxide-releasing moiety. Compared with ASA, NCX-4016 has a broader spectrum of antithrombotic and antiinflammatory activities. We hypothesized that NCX-4016 might inhibit in vivo lipopolysaccharide (LPS)-induced expression of tissue factor (TF).

METHODS AND RESULTS

Rats were administered 90 mg/kg NCX-4016 orally for 5 days. Placebo, 50 mg/kg ASA, and 80 mg/kg isosorbide-5-mononitrate (ISMN) were used in control groups. On day 5, rats were injected intraperitoneally with 100 microg/kg LPS and killed 6 hours later. The expression of TF in monocytes was measured by flow cytometry and Western blot analysis. Reverse transcriptase-polymerase chain reaction was performed to assess expression of TF and cyclooxygenase-2 (COX-2) genes. Plasma concentrations of interleukin-1beta and tumor necrosis factor-alpha were measured. Urine samples were collected to evaluate the excretion of the thromboxane metabolite 11-dehydro-thromboxane (TX)B2. Gastric mucosa was inspected. LPS injection was followed by synthesis TF and COX-2 mRNAs in circulating monocytes, which were blunted by NCX-4016 but not by ASA or ISMN. Both NCX-4016 and ISMN reduced TF expression on surface of circulating monocyte. LPS increased the excretion 11-dehydro-TXB2, and this was prevented by NCX-4016 and ASA. Unlike ASA, NCX-4016 reduced plasma interleukin-1beta and tumor necrosis factor-alpha. In addition, NCX-4016 almost completely prevented mucosal damage, whereas ASA increased the extension of gastric lesions in LPS-injected rats.

CONCLUSIONS

NCX-4016 prevents monocyte TF expression; this is accompanied by inhibition of TX and cytokine biosynthesis. These additive effects of nitric oxide release and COX inhibition may help explain efficacy and tolerability of NCX-4016.

Plasminogen activators in inflammation and sepsis

Mortality of severe sepsis remains at 40% to 50%. Intensive efforts over the past two decades have only marginally improved outcome. Improving outcome in sepsis depends on understanding its pathophysiology, which involves triggers, responses of the organism, and dysfunction. Stress, injury, or infection trigger host responses, including local and systemic orchestrated mechanisms. Dysfunction and outcome depend on both trigger and response. Blood coagulation, inflammation, immunity, and fibrinolysis are critical components of the organism's responses. Understanding their role in sepsis pathophysiology is the key to effective treatment. Relevant studies were identified by a systematic literature search, complemented by manual search of individual citations. Using PubMed, 'sepsis' yields more than 62,000 references, 'plasminogen activators' more than 21,000. The selection of citations was guided by preference for reviews that expand important threads of argumentation. Single original studies were included when relevant to critical points. This analytical review describes the essential elements of pathophysiology and the current status of sepsis treatment. Based on this context, an emerging therapeutic option will be discussed: plasminogen activators.

Tissue factor and angiogenesis in cancer

Idiopathic thrombosis often precedes the diagnosis of occult cancer by several years. Whether hypercoagulability predisposes for malignancy or the converse holds true is an unresolved paradigm that stems from the known vicious cycle of clot formation and tumor growth. Central to this paradigm is the interplay between tissue factor (TF), the initiator of coagulation, and angiogenesis, the life support of tumors. Both clotting-dependent and -independent mechanisms of TF-induced angiogenesis have been elucidated that may signal through distinct pathways. This review focuses on the latest studies of TF and angiogenesis and highlights recent applications that have led to the development of promising new TF-targeted cancer therapeutics. Finally a cautionary note is given about unexpected complications arising from antiangiogenic therapy that may potentially involve TF.

Angiogenesis, thrombospondin, and ductal carcinoma in situ of the breast

Angiogenesis, the growth of new vessels from existing vasculature, plays an essential role in tumour development. The process involves interaction between a variety of cells, growth factors, and components of the extracellular matrix, regulated by pro-angiogenic and anti-angiogenic factors. This review profiles these factors, outlines the available methods for measuring new vessel formation, and discusses the importance of angiogenesis in breast cancer, with emphasis on ductal carcinoma in situ.

A peptide derived from human prothrombin fragment 2 inhibits prothrombinase and angiogenesis

We constructed the synthetic peptide library representing human prothrombin fragment 2 (F2) sequence and explored the inhibitory sequence for prothrombinase, which was reconstituted in vitro by adding factor Xa, factor Va, and calcium into phospholipids. The nonapeptide NSAVLQVEN (NSA9) suppressed prothrombinase reconstituted not only on phospholipid vesicles but also on the bovine capillary endothelial (BCE) cell surface. Kinetic analyses demonstrated that NSA9 is a mixed-type inhibitor of Xa. Furthermore, the nonapeptide inhibited the proliferation of BCE cells and also suppressed angiogenesis in chicken embryos. The inhibitory activities of NSA9 were abrogated by pre-incubation with anti-F2 monoclonal antibody, 4E7. These data demonstrate that anti-angiogenic activity of F2 may be related to its ability to inhibit prothrombinase.