Indirect Activation of Blood Coagulation in Colon Cancer

Hypochlorite-induced aggregation of fibrinogen underlies a novel antioxidant role in blood plasma

Fibrinogen, a major constituent of blood plasma, is highly susceptible to reaction with biological oxidants. It has been proposed that fibrinogen plays a role in antioxidant defence, but oxidation of fibrinogen is also known to disrupt normal blood clotting and is implicated in the pathology of atherosclerosis. In the present study, we show that the biological oxidant hypochlorite promotes the formation of soluble high molecular weight fibrinogen assemblies ≥40 × 10⁶ Da, that do not accumulate when fibrinogen is induced to aggregate by other stresses such as heating or hydroxyl-mediated damage in vitro. Hypochlorite-modified fibrinogen is stable at 37 °C as assessed by precipitation assays, and has reduced susceptibility to iron-induced (hydroxyl-mediated) precipitation compared to native fibrinogen. In contrast to hypochlorite-modified albumin, which is known to be immunostimulatory, hypochlorite-modified fibrinogen does not induce RAW 264.7 (macrophage-like) cells or EOC 13.31 (microglia-like) cells to produce reactive oxygen species or induce cell death. Furthermore, depletion of fibrinogen from human blood plasma increases the immunostimulatory property of blood plasma after it is supplemented with hypochlorite in situ. We propose that reaction of hypochlorite with fibrinogen in blood plasma potentially reduces the accumulation of other hypochlorite-modified species such as immunostimulatory hypochlorite-modified albumin. The latter represent a novel role for fibrinogen in blood plasma antioxidant defence.

Preoperative plasma fibrinogen, but not D-dimer might represent a prognostic factor in non-metastatic colorectal cancer: A prospective cohort study

BACKGROUNDS

Cancer progression has been associated with host hemostasis system. Whether preoperative plasma hemostasis factors can predict survival in colorectal cancer is quite intriguing.

METHODS

We conducted a prospective cohort study to validate the prognostic significance of three hemostasis parameters - fibrinogen, fibrin degradation products (FDPs) and D-dimer - in non-metastatic colorectal cancer patients treated with curative resection.

RESULTS

All three parameters were positively correlated with C reactive protein (CRP) levels and Glasgow Prognostic scores (GPS). In univariate cox hazards regression model, as continuous variables, both fibrinogen (HR: 1.07, 95%CI: 1.01-1.13) and FDPs (HR: 1.17, 95%CI: 1.05-1.31) were prognostic, while D-dimer levels were not. Patients with hyperfibrinogenemia had a 2.12-fold increased mortality risk compared with patients without hyperfibrinogenemia. Patients with positive FDPs had a 3.68-fold increased mortality risk compared with patients with negative FDPs. In multivariate models, hyperfibrinogenemia was prognostic (HR: 3.39, 95%CI: 1.34-8.67) in patients with normal GPS scores.

CONCLUSIONS

Preoperative fibrinogen levels appeared as an independent mortality risk factor in non-metastatic colorectal cancer patients with normal GPS scores. Fibrinogen could be a reliable marker to identify high risk patients for those without systematic inflammation responses.

Subventricular zone involvement in Glioblastoma - A proteomic evaluation and clinicoradiological correlation

Glioblastoma multiforme (GBM), the most malignant of all gliomas is characterized by a high degree of heterogeneity and poor response to treatment. The sub-ventricular zone (SVZ) is the major site of neurogenesis in the brain and is rich in neural stem cells. Based on the proximity of the GBM tumors to the SVZ, the tumors can be further classified into SVZ+ and SVZ−. The tumors located in close contact with the SVZ are classified as SVZ+, while the tumors located distantly from the SVZ are classified as SVZ−. To gain an insight into the increased aggressiveness of SVZ+ over SVZ− tumors, we have used proteomics techniques like 2D-DIGE and LC-MS/MS to investigate any possible proteomic differences between the two subtypes. Serum proteomic analysis revealed significant alterations of various acute phase proteins and lipid carrying proteins, while tissue proteomic analysis revealed significant alterations in cytoskeletal, lipid binding, chaperone and cell cycle regulating proteins, which are already known to be associated with disease pathobiology. These findings provide cues to molecular basis behind increased aggressiveness of SVZ+ GBM tumors over SVZ− GBM tumors and plausible therapeutic targets to improve treatment modalities for these highly invasive tumors.

D-Dimer and Carcinoembryonic Antigen Levels: Useful Indicators for Predicting the Tumor Stage and Postoperative Survival

The purpose of this prospective study is to determine the preoperative plasma D-dimer and serum Carcinoembryonic Antigen (CEA) levels of patients scheduled for curative surgical resection for colorectal cancer and to evaluate the significance of these levels on the prognosis and postoperative survival rate. One hundred sixty-five patients with colorectal cancer, who were scheduled to have elective resection between January 2008 and January 2011, were included in the study. A significant increase was observed in the D-dimer levels, particularly in poorly differentiated tumors. The distance covered by the tumor inside the walls of the colon and rectum (T-stage) was significant for both D-dimer and CEA levels. As the T-stage increased, there was also a significant increase in the D-dimer and CEA levels. A high significance and correlation level was detected between the TNM staging and both D-dimer and CEA. A significant relationship was found between the advanced tumor stage and short postoperative survival rate of patients with colorectal cancer. Therefore, the analysis of preoperative D-dimer and CEA levels can be useful in predicting the stage and differentiation of the tumor and the postoperative survival rate.

Phosphatidylserine exposing-platelets and microparticles promote procoagulant activity in colon cancer patients

Background

Colon cancer is invariably accompanied by altered coagulation activity; however, the precise role of phosphatidylserine (PS) in the hypercoagulable state of colon cancer patients remains unclear. We explored the exposure of PS on platelets and microparticles (MPs), and evaluate its role in procoagulant activity in colon cancer patients.

Methods

PS-positive platelets and MPs, mainly from platelets and endothelial cells, were detected by flow cytometry and confocal microscopy, and their procoagulant activity was assessed with purified coagulation complex assays, clotting time, and fibrin turbidity.

Results

Plasma levels of PS-positive platelets increased gradually from stage I to IV and were higher in all stages of the patients than in the healthy control, while PS-positive platelet-derived MPs only increased significantly in stage III/IV patients. Meanwhile, PS-positive MPs and endothelial-derived MPs in stage II/III/IV patients were markedly higher than ones in controls but no difference with stage I. Tissue factor positive MPs were higher in all 4 stages of colon cancer patients than in the healthy control. Platelets and MPs from the patients demonstrated significantly enhanced intrinsic/extrinsic FXa and thrombin generation, greatly shortened coagulation time, and increased fibrin formation. Combined treatment with PS antagonist lactadherin, strongly prolonged the coagulation time and reduced fibrin formation by inhibiting factor tenase and prothrombinase complex activity. In contrast, pretreatment with anti tissue factor antibody played a lesser role in suppression of procoagulant activity.

Conclusion

Our results suggest that PS-positive platelets and MPs contribute to hypercoagulability and represent a potential therapeutic target to prevent coagulation in patients with colon cancer.

Acute phase proteins are major clients for the chaperone action of α₂-macroglobulin in human plasma

Extracellular protein misfolding is implicated in many age-related diseases including Alzheimer's disease, macular degeneration and arthritis. In this study, putative endogenous clients for the chaperone activity of α₂-macroglobulin (α₂M) were identified after human plasma was subjected to physiologically relevant sheer stress at 37 °C for 10 days. Western blot analysis showed that four major acute phase proteins: ceruloplasmin, fibrinogen, α₁-acid glycoprotein and complement component 3, preferentially co-purified with α₂M after plasma was stressed. Furthermore, the formation of complexes between α₂M and these putative chaperone clients, detected by sandwich ELISA, was shown to be enhanced in response to stress. These results support the hypothesis that α₂M plays an important role in extracellular proteostasis by sequestering misfolded proteins and targeting them for disposal, particularly during acute phase reactions.

Co-localization of Protein Z, Protein Z-Dependent protease inhibitor and coagulation factor X in human colon cancer tissue: implications for coagulation regulation on tumor cells

INTRODUCTION

Several hemostatic system components, including factor X (FX), contribute to cancer progression. The Protein Z (PZ)/protein Z-dependent protease inhibitor (ZPI) complex directly inhibits factor Xa proteolytic activity. The aim of this study was to determine the antigenic distribution of ZPI and PZ, in relation to FX, as well as indicators of blood coagulation activation (F1+2 and fibrin) in human colon cancer tissue.

MATERIALS & METHODS

Studies were performed on human colon cancer fragments. Immunohistochemical (IHC) ABC procedures and double staining method employed polyclonal antibodies against PZ, FX, F1+2 and monoclonal antibodies against ZPI and fibrin. In-situ hybridization (ISH) methods employed biotin-labeled 25-nucleotide single-stranded DNA probes directed to either FX, PZ or ZPI mRNAs.

RESULTS

Expression of FX, PZ and ZPI in association with colon cancer cells was observed by IHC. Moreover, the presence of both F1+2 and fibrin in association with colon cancer cells was found, which indicates that blood coagulation activation proceeds extravascularly at the tumor site. Furthermore, expression of FX and PZ was visualized in association with endothelial cells. In turn, colon cancer-associated macrophages were characterized by FX , PZ and ZPI presence. The double staining studies revealed strong FX/PZ, FX/ZPI, as well as PZ/ZPI co-localization on colon cancer cells. ISH studies revealed the presence of FX mRNA, PZ mRNA and ZPI mRNA in colon cancer cells indicating induced synthesis of these proteins.

CONCLUSIONS

The localization of PZ/ZPI and FX in colon cancer cells indicates that PZ/ZPI may contribute to anticoagulant events at the tumor site. Strong co-localization of PZ/ZPI and FX in cancer cells, and the presence of the mRNAs encoding the proteins, suggests their role in the tumor's biology. However, the presence of F1+2 and fibrin at the colon cancer site also suggests that the regulation of FXa by the PZ/ZPI complex at this site is incomplete.

Blood coagulation factor Xa as an emerging drug target

INTRODUCTION

Factor (F)Xa is well-known as an important player in the coagulation cascade responsible for thrombin generation. More recently, FXa emerged as an essential player in cell biology via activation of protease-activated receptors (PAR)-1 and -2. This pleiotropic role of FXa forms the basis for its potential contribution to the pathogenesis of several diseases.

AREAS COVERED

The role of FXa in pathophysiology is reviewed with special emphasis on its signal transduction properties. To this end, we first discuss the important role of FXa in the coagulation cascade, we continue with recent data on FXa induced signaling in pathophysiology with special emphasis on tissue remodeling and fibrosis and discuss the potential of FXa as an emerging drug target.

EXPERT OPINION

FXa is more than a passive intermediate in the coagulation cascade and FXa may in fact orchestrate fundamental processes during pathophysiology. Targeting FXa may be an exciting new therapeutic strategy in the treatment of (fibro)proliferative diseases for which current treatment options are limited.

Expression of protein C (PC), protein S (PS) and thrombomodulin (TM) in human colorectal cancer

INTRODUCTION

Colorectal cancer (CRC) is often complicated by thromboembolic episodes. It has been recognized that blood coagulation proteins play a role in cancer progression. An important inhibitory mechanism is provided by the protein C (PC) system consisting of PC, protein S (PS) and thrombomodulin (TM). Recently, novel biological activities have been ascribed to the PC system that do not relate to their hemostatic functions, eg. in angiogenesis, apoptosis and inflammation.

OBJECTIVES

The purpose of the study was to elucidate the solid phase interactions between CRC tissue and components of the PC system that may contribute to tumor progression.

MATERIAL AND METHODS

CRC tissues were obtained at surgical resection during treatment of 66 patients. Immunohistochemical studies were performed using polyclonal antibodies against PC, PS and TM. A semiquantitative analysis of the protein expression was also performed.

RESULTS

Weak expression of PC was observed in cancer cells of two-thirds of the specimens examined, while in 3/66 cases there was no staining for PC in cancer cells. One fourth of CRCs exhibited strong expression of PC. The presence of PS was demonstrated in 64/66 cases of CRC. However, its expression was irregular in terms of intensity of staining and percentage of cancer cells exhibiting protein expression. Weak expression of TM was demonstrated in two thirds of the cases examined, while a strong TM staining was revealed in one third of colon cancers.

CONCLUSION

Heterogeneous expression of the PC system components in CRC tissue may point to their biological activity modulating tumor growth.

Identification of protein clusters predictive of response to chemotherapy in breast cancer patients

An attempt for the identification of potential biomarkers predictive of response to chemotherapy (CHT) in breast cancer patients has been performed by the use of two-dimensional electrophoresis and mass spectrometry analysis. Since growth and progression of tumor cells depend also on stromal factors in the microenvironment, we choose to investigate the proteins secreted in Tumor Interstitial Fluid (TIF) and in Normal Interstitial Fluids (NIF). One-hundred and twenty-two proteins have been analyzed and a comparison was also made between the proteomic profile of responders versus nonresponders to CHT. At baseline, proteins isolated in TIF and NIF of all the 28 patients show significant differences in expression. Two clusters of proteins, differentially expressed in TIF with respect to NIF were found. Most significant is the decreased expression in TIF of CRYAB. In the protein metabolism group, also FIBB was found decreased. Some proteins involved in energy pathways were overexpressed (PGAM-1, ALDO A, PGK1, G3Pcn), while some other were down-regulated (CAH2, G3Pdx, PRDX6, TPIS). The same trend was observed for signal transduction proteins, with 14-3-3-Z overexpressed, and ANXA2 and PEBP 1 down-regulated. Moreover, an analysis has been conducted comparing protein expression in interstitial fluids of responders and nonresponders, irrespective of TIF or NIF source. This analysis lead us to identify two clusters of proteins with a modified expression, which might be predictive of response to CHT. In responders, an increase in expression of LDHA, G3Pdx, PGK1sx (energy pathways), VIME (cell growth and maintenance) and 14-3-3-Z (signal transduction), coupled with a decreased expression of TPIS, CAH 2, G3Psx, PGK 1dx (energy pathways), TBB5 (cell growth and maintenance), LDHB and FIBB (protein metabolism), was found. We observed that CHT modifies the expression of these cluster proteins since, after treatment, their expression in TIF of responder is generally decreased. Patients not responding to CHT show an unchanged expression pattern in TIF, with the exception of protein 14-3-3-Z, which is overexpressed, and a decreased expression in NIF of several cluster proteins. In conclusion, the identification of protein clusters associated with response to CHT might be important for predicting the efficacy of a specific antineoplastic drug and for the development of less empiric strategies in choosing the therapy to be prescribed to the single patient.

Identification of human plasma proteins as major clients for the extracellular chaperone clusterin

Clusterin (CLU) is an extracellular chaperone that is likely to play an important role in protein folding quality control. This study identified three deposition disease-associated proteins as major plasma clients for clusterin by studying CLU-client complexes formed in response to physiologically relevant stress (shear stress, approximately 36 dynes/cm(2) at 37 degrees C). Analysis of plasma samples by size exclusion chromatography indicated that (i) relative to control plasma, stressed plasma contained proportionally more soluble protein species of high molecular weight, and (ii) high molecular weight species were far more abundant when proteins purified by anti-CLU immunoaffinity chromatography from stressed plasma were compared with those purified from control plasma. SDS-PAGE and Western blot analyses indicated that a variety of proteins co-purified with CLU from both stressed and control plasma; however, several proteins were uniquely present or much more abundant when plasma was stressed. These proteins were identified by mass spectrometry as ceruloplasmin, fibrinogen, and albumin. Immunodot blot analysis of size exclusion chromatography fractionated plasma suggested that CLU-client complexes generated in situ are very large and may reach >or=4 x 10(7) Da. Lastly, sandwich enzyme-linked immunosorbent assay detected complexes containing CLU and ceruloplasmin, fibrinogen, or albumin in stressed but not control plasma. We have previously proposed that CLU-client complexes serve as vehicles to dispose of damaged misfolded extracellular proteins in vivo via receptor-mediated endocytosis. A better understanding of these mechanisms is likely to ultimately lead to the identification of new therapies for extracellular protein deposition disorders.

Tissue factor and tumor: clinical and laboratory aspects

This review summarizes data demonstrating the role of TF in tumor development, metastasis and angiogenesis. TF is a transmembrane protein that is expressed constitutively in some kinds of extravascular cells and transiently in intravascular cells after stimulation with cytokines and growth factors. Originally TF was considered to have a function in the initiation of coagulation. In the last years it became evident that TF plays a role in physiological and pathological processes outside the hemostasis. Up-regulation of TF expression appears to be characteristic of tumor tissue. In a variety of human tumors it was shown by immunohistochemistry, that TF can be expressed in malignant cells as well as in tumor-infiltrating macrophages or endothelial cells. Such abnormal TF expression contributes to the angiogenic process by a shift in the balance between endogenous proangiogenic and antiangiogenic factors. Observations of a significant correlation between elevated TF expression with increased microvessel density and VEGF expression underline the TF involvement in tumor angiogenesis. Furthermore, TF expression influences also metastasis. The effect of TF on metastasis may result from its angiogenic effect, but also from the production of growth factors or adhesion proteins.

Tumors and fibrinogen. The role of fibrinogen as an extracellular matrix protein

The progression of a tumor from benign and localized to invasive and metastatic growth is the major cause of poor clinical outcome in cancer patients. Much like in a healing wound, the deposition of fibrin(ogen), along with other adhesive glycoproteins, into the extracellular matrix (ECM) serves as a scaffold to support binding of growth factors and to promote the cellular responses of adhesion, proliferation, and migration during angiogenesis and tumor cell growth. Inappropriate synthesis and deposition of ECM constituents is linked to altered regulation of cell proliferation, leading to tumor cell growth and malignant transformation. Fibrin deposition occurs within the stroma of a majority of tumor types. In contrast, abundant FBG, not fibrin, is present within the stroma of breast cancers. It is thought to originate from exudation of plasma FBG and subsequent deposition into the tumor stroma and not endogenous synthesis and secretion of FBG by breast tumor cells. However, we show that MCF-7 human breast cancer cells synthesize and secrete FBG polypeptides, suggesting that the origin of FBG in the stroma of breast carcinoma may be due to endogenous synthesis and deposition. Moreover, FBG assembles into ECM as conformationally altered FBG, not as fibrin. Studies in our laboratory demonstrate that FBG alters the ability of breast cancer cells to migrate. Together, the results of studies from our laboratory, as well as the laboratories of others, indicate that the presence of fibrin(ogen) within the tumor stroma likely affects the progression of tumor cell growth and metastasis. This review focuses on FBG within tumors and its relationship with other tumor constituents, ultimately focusing on the role of FBG in breast cancer.

Plasma D-dimer level in patients with colorectal cancer: its role as a tumor marker

The purpose of this study was to explore the relationship between the preoperative plasma D-dimer (DD) levels and the tumor pathology of colorectal cancer. The plasma DD levels were measured preoperatively in 108 patients with colorectal cancer, and then were correlated with the tumor pathology and stage. The diagnostic value of the DD levels for the tumor stage was then compared with that of the preoperative carcinoembryonic antigen (CEA) levels. The preoperative DD levels were higher in patients with either a large-sized tumor or a tumor showing deep wall penetration. Lymph-node metastasis, lymphatic invasion, hepatic metastasis, and peritoneal dissemination were all associated with higher DD levels. A stepwise increase in the median DD level was found with the tumor stage. The preoperative DD levels also significantly correlated with CEA levels. When a cutoff value of 0.6 microg/ml was used in the DD assay, the sensitivity and specificity for Dukes C or D cancer were 67.2% and 64.0%, and those for Dukes D cancer were 91.3% and 57.6%, respectively. Although the DD assay was less specific, its diagnostic value in the preoperative staging of colorectal cancer was comparable to that of the CEA assay. The measurement of the preoperative DD level is thus considered to be useful for the preoperative staging of colorectal cancer.

Fibrin and fibrinogen degradation products in plasma of patients with colorectal adenocarcinoma

PURPOSE

The aim of the present study was to correlate the preoperative plasma levels of TDP in patients with colorectal cancer to tumor stage, metastasis, and postoperative thromboembolic complications.

METHODS

Ninety-one patients with colorectal cancer, 20 patients with colorectal adenoma, and 71 patients without neoplastic lesions in the colon or rectum were included in this prospective study. Before surgery, total fibrin and fibrinogen degradation products (TDP) were measured in plasma of all patients with a specific enzyme-linked immunosorbent assay test. Phlebography was performed postoperatively in 82 of 91 patients with colorectal cancer.

RESULTS

Median TDP in plasma of patients with colorectal cancer (805 (range, 339-5,024) ng fibrinogen equivalents (ngFE)) was significantly higher than TDP in patients with colorectal adenoma (591 (range, 417-1386) ngFE/ml) and TDP in patients without neoplastic lesions in the colon (632.8 (range, 180-2622) ngFE/ml; P < or = 0.003). In patients with colorectal cancer and liver metastasis, TDP in plasma (1085.5 (range, 468-5024) ngFE/ml) was significantly higher than in patients with localized tumor growth (753 (range, (339-2,780) ngFE/ml; P < or = 0.02). Twenty of 82 patients (24 percent) with cancer developed thromboembolic complications. TDP was preoperatively significantly higher in this group of patients (1,101 (range, 468-2,167) ngFE/ml) compared with patients without thromboembolic complications (753 (range, 339-5024) ngFE/ml; P < or = 0.04).

CONCLUSION

Preoperative plasma levels of TDP were elevated in patients with colorectal cancer, especially in patients with liver metastasis and in patients developing postoperative deep venous thrombosis.

Haemostasis activation markers in plasma of patients with benign and malignant gynaecological tumours: a pilot study

Coagulation and fibrinolysis activation have been investigated in fifty-eight women with recently detected gynaecological tumours. Twenty-six were benign and 32 malignant: of the last group nine patients had metastases. A control group consisted of 31 age-matched healthy women. Prothrombin fragment 1 + 2, thrombin-antithrombin III and D-dimer were measured. The median values of all analytes were significantly higher in the malignant tumour group, but not in the benign tumour group, as compared to the control group. The group of patients with a gynaecological tumour and metastases differed from the non-metastasized tumour group in prothrombin fragment 1 + 2, thrombin-antithrombin III and D-dimer. In the non-metastasized malignant tumour group solely prothrombin fragment 1 + 2 was significantly higher than in the benign tumour group. Coagulation and fibrinolysis predominating as can be derived from the elevated D-dimer/thrombin-antithrombin III and D-dimer/prothrombin fragment 1 + 2 ratios. The studied constituents do not enable a differentiation between the benign and malignant processes. However, as the differences of these values in both malignant tumour groups were significant, this might be used to trace the existence of metastases in gynaecological tumours. Investigation of these analytes in several specific types of gynaecological tumours might be clinically relevant.

Coagulation factor XIII in plasma of patients with benign and malignant gynaecological tumours

Fibrinogen and factor XIII were measured in sixty-four women with recently detected gynaecological tumours. Twenty-six of these tumours were benign and 32 were malignant: of the last group, nine patients had metastases. No patient showed clinical signs of bleeding or thrombosis. A reference group consisted of 31 age-matched healthy women. For fibrinogen, no significant deviation between the patient groups and the control group was found. The median values of factor XIII were higher in the benign tumour group than in the control group. In patients with a gynaecological tumour and metastases, factor XIII was significantly lower than in the non-metastasized malignancy group or in the benign tumour group.

Enhanced antitumor effect of Bacillus Calmette-Guérin in combination with fibrinogen on urinary bladder tumor

Although intravesical instillation of Bacillus Calmette-Guérin (BCG) is an established and effective therapy for superficial urinary bladder tumor (UBT), the current major problems are BCG-resistant UBT and recurrence after BCG therapy. The injection of BCG and fibrinogen could be expected to induce the formation of a fibrin mesh, which would trap BCG and and prolong its antitumor action. The present study has been designed to investigate whether fibrinogen has the ability to augment antitumor activity of BCG against UBT. A single injection of BCG/fibrinogen solution into the subcutaneous tissue of C3H/He mice was performed. Histopathological examination revealed prolonged accumulation of BCG and marked infiltration of inflammatory cells at the injected site, as compared with the injection of BCG or fibrinogen alone. When BCG was used in combination with gelatin sponge, prolonged BCG accumulation was also observed, but not many inflammatory cells were induced, as compared with injection of BCG/fibrinogen combination. When BCG/fibrinogen solution was injected into MBT-2 murine UBT transplanted into C3H/He mice, the formation of fibrin fibers, which trap BCG, was induced, and many inflammatory cells around the tumor were seen. A pronounced inhibitory effect on tumor growth and prolonged survival of tumor-bearing mice were achieved, as compared with the injection of BCG alone. Dead BCG/fibrinogen solution had a modest inhibitory effect on the tumor growth. This study suggests that combination treatment with BCG and exogenous fibrinogen may prolong accumulation of BCG by BCG by trapping BCG in fibrin meshwork, and may induce marked infiltration of inflammatory cells into tumor stroma, causing marked regression of the tumor. The possible clinical implications of the combined use of BCG and fibrinogen are discussed.

Correlation between increased granulocyte elastase release and activation of blood coagulation in patients with lung cancer

BACKGROUND

Coagulopathies often are associated with malignant tumors. The pathogenesis of these complications in cancer is not clear. Host inflammatory (monocyte/macrophage) cell-mediated triggering of clotting activation has been suggested.

METHODS

The objective of this study was to evaluate the role of neutrophil-derived elastase in the activation of blood coagulation and fibrinolysis in lung cancer. The study population was 42 consecutive patients with lung cancer (34 men and 8 women). Thirteen patients had small cell lung cancer (SCLC), 13 had squamous cell lung cancer, and 16 had adenocarcinoma. Hemostatic function was assessed by measuring D-dimer (DD), thrombin-antithrombin III complex (TAT), plasmin-alpha 2-antiplasmin complex (PAP), fibrin degradation product (FDP), fibrinogen, prothrombin time (PT) and activated partial thromboplastin time (APTT). Elastase-alpha 1-protease inhibitor (EPI) complex was measured as a marker of neutrophil activation.

RESULTS

Significant elevation of the elastase plasma levels and coagulation-fibrinolysis parameters was found in patients with cancer compared with control subjects. Among all patients, the plasma concentration of EPI was significantly correlated with APTT, DD, TAT, PAP, and fibrinogen. Although in patients with non-small cell lung cancer (non-SCLC), DD, TAT, PAP, APTT, and fibrinogen were significantly correlated with EPI, such a correlation was not found in patients with SCLC. Patients with non-SCLC had stronger correlation of EPI with TAT, PAP, and PT than did patients with advanced stages of disease.

CONCLUSION

The activation of coagulation-fibrinolysis system in lung cancer may be triggered, at least in part, by an increased release of neutrophil elastase. This mechanism is stage related and seems to operate predominantly in non-SCLC.

Thrombin enhances tumor cell adhesive and metastatic properties via increased alpha IIb beta 3 expression on the cell surface

The association between blood coagulation and cancer growth and metastatic dissemination is not yet completely understood. In this study we demonstrate that thrombin is capable of enhancing tumor cell adhesive properties and thereby increases tumor cell metastatic potential. Following exposure to alpha-thrombin, Walker 256 carcinosarcoma cells and B16 amelanotic melanoma cells became more adherent to both endothelial cell monolayers and the subendothelial matrix component, fibronectin. Preincubation of W256 and B16a cells with doses of alpha-thrombin from 0.01 to 10.0 U/ml produced a bell shape dose-response curve with the maximal effect (a 2-5-fold increase in adhesion) observed at 0.1 U/ml (corresponding to 0.8 nM). Complexes of alpha-thrombin with its inhibitors, hirudin and antithrombin III-heparin, diminished its effect on tumor cell adhesion. The effect of thrombin on tumor cell adhesion may be mediated by the alpha IIb beta 3 integrin as thrombin increased cell surface expression of the alpha IIb beta 3 complex. The significance of the in vitro observations was further substantiated by results of in vivo studies. Pretreatment of B16a cells with alpha-thrombin resulted in a 2-fold increase in the number of metastatic lung colonies in an experimental metastasis model. The data indicate a new role for thrombin in the metastatic spread of cancer.

The role of fibrin in tumor metastasis

A volume of data that has accumulated for over a century has suggested that fibrin may facilitate the persistence and progression of malignancy. Techniques that have been developed recently have shown that fibrin is indeed a component of the connective tissue stroma in human malignancy but in only a few tumor types. However, therapeutic intervention studies with drugs that limit thrombin activity or enhance fibrinolysis have shown favorable clinical effects in at least one such tumor type. These favorable findings affirm the concept that cause-and-effect relationships do, in fact, exist between thrombin generation with fibrin formation and tumor progression, and suggest that a rational basis exists for the design of future drug intervention trials that target reactions relevant to specific tumor types. These findings also provide a basis for the design of experiments capable of defining further the role of fibrin in the integrity of these tumor types. Because fibrinogen is found much more commonly than fibrin in the connective tissue of a variety of human malignancies, attention might reassumably be directed to determining the possible contribution of this molecule as well as of fibrin to tumor progression.

Tissue factor as a tumor procoagulant

Tissue factor is a cell surface glycoprotein responsible for initiating the extrinsic pathway of coagulation. Many tumor cell homogenates and intact tumor cells have been shown to contain tissue factor activity. Immunohistochemical studies show that many tumors associated with Trousseau's syndrome express tissue factor on their cell surfaces. Tumor cells shed membrane fragments which carry tissue factor that can account for the activation of the clotting system. Tumor cells also produce soluble substances that can induce tissue factor expression on host cells, such as endothelium and monocytes, at sites distant from the tumor. Although, all the functional TF molecules are localized on the outer cell membrane in many tumor cells, the procoagulant activity on the intact cell surface is largely dormant and can be greatly enhanced upon cell injury or damage. Tissue factor procoagulant activity on the cell surface can be modulated by alterations in the plasma membrane without loss of cell viability. Tissue factor activity on cell surfaces is largely regulated by a plasma inhibitor, tissue factor pathway inhibitor. This inhibitor binds to both functional and non-functional tissue factor/VIIa complexes on the cell surface and prevents non-functional tissue factor/VIIa complexes from becoming functional after cell injury or lysis. Heparin, but not warfarin, therapy is effective in preventing the occurrence of devastating thrombotic events in patients with Trousseau's syndrome and the reason(s) for this are still unknown.

Clinical trials with anticoagulant and antiplatelet therapies

Clinical trials of drugs that influence coagulation and fibrinolysis pathways have been undertaken in patients with malignancy because these pathways are capable of influencing malignant progression. The validity of this concept was originally confirmed in experimental animal models of malignancy. Earlier pilot studies in human disease have been succeeded by definitive prospective randomized clinical trials that have revealed heterogeneity of responsiveness to anticoagulant and fibrinolytic agents that may be attributable to differences in mechanisms of interaction of the tumor cells of various types of malignancy with these pathways in vivo. In certain tumor types studied thus far, increased tumor response rates and prolongation of survival have been observed that suggest the possibility that substantial benefit may be realized from this treatment approach in patients with malignancy. In addition, the availability of newer and potentially more effective therapeutic agents holds promise for even greater gains in previously tested tumor types. The ability to design treatment regimens that correspond to defined mechanisms that pertain to specific tumor types should permit future studies to be designed rationally. Current data suggest that anticoagulant and fibrinolytic agents might reasonably be tested in tumor types characterized by the existence of a tumor cell-associated coagulation pathway with thrombin generation and conversion of fibrinogen to fibrin (such as small cell carcinoma of the lung). By contrast, protease inhibitors might reasonably be tested in tumor types characterized by expression of tumor cell plasminogen activators. Expansion of current views on the possible role of antithrombic drugs in cancer therapy is justified. For example, antithrombotic drugs classified as non-steroidal anti-inflammatory agents may inhibit carcinogenesis while polyanionic drugs with anticoagulant properties, such as suramin and heparin, may inhibit growth factor interactions with cells. Intriguing new opportunities clearly exist for interactions between clinical and basic investigators that may provide both novel biologic insights and improved patient care.

Immunohistochemical identification of tissue factor in solid tumors

Patients with cancer experience a much higher than expected incidence of thromboembolic disorders, commonly referred as Trousseau syndrome. Although this association has been well documented, the etiology of the hypercoagulable state is not known. The expression on tumor cells of tissue factor (TF), a membrane-bound lipoprotein that functions as a cofactor to factor VIIa in the initiation of the extrinsic pathway of blood coagulation, has been postulated as a possible mechanism. Whereas the distribution of TF in normal tissues is known, no large survey of TF expression in malignant tissues has been reported. In this study a polyclonal, monospecific rabbit anti-human TF IgG was used for immunohistochemical localization of TF antigen in 85 different tumor specimens. In general, cell types which normally express TF continued to do so after malignant transformation (41 of 60 epithelial tumor specimens were positive for TF). Tumors of nonepithelial origin frequently lacked TF, with only 3 of 19 specimens containing evidence of TF antigen. In addition five of six benign tumors did not express TF. Many tumor types commonly associated with Trousseau syndrome, for example lung, pancreatic, breast, colon and gastric carcinomas, stained positively for TF. Based on this survey, it appears that TF expression by tumors may be an important factor in the pathogenesis of a hypercoagulable state in some patients with cancer.

Pathways of coagulation activation in situ in rheumatoid synovial tissue

Immunohistochemical techniques were applied to rheumatoid synovium in order to detect components of coagulation and fibrinolysis pathways within these tissues. These techniques revealed an intact coagulation pathway and plasminogen activator inhibitor-2 associated with macrophage-like cells that were present throughout these tissues, especially in subsurface areas. Cell-associated thrombin generation appeared to account for conversion of abundant fibrinogen to fibrin. Occasional macrophage-like cells also stained for urokinase but tissue-type plasminogen activator and plasminogen activator inhibitor-1 were restricted to vascular endothelium. Intense synovial fibrin deposition (with the limited evidence for associated fibrinolysis) may contribute to local inflammation and explain certain clinical features of rheumatoid arthritis. These findings suggest novel treatment hypotheses for this disease.

Use of fibrinogen to enhance the antitumor effect of OK-432. A new approach to immunotherapy for colorectal carcinoma

OK-432 (5 KE), an immunomodulatory agent prepared from an attenuated strain of Streptococcus pyogenes, was dissolved in 1 ml of aprotinin (1000 KIE) and mixed with 80 mg of fibrinogen containing Factor XIII. A single intratumoral injection of the mixture was performed preoperatively under endoscopy in 20 patients with colorectal carcinoma. Postoperative histopathologic examinations revealed the formation of fibrin fibers at the site of injection and marked infiltration of inflammatory cells into the tumor stroma on the day after injection; the formation of granulomas containing many giant cells after 4 to 7 days; and extensive regression of tumor tissue after 14 days. This study suggests that the high concentration of exogenous fibrinogen gelatinized enough to trap OK-432 in tumor stroma and that OK-432 induced granulomatous hypersensitivity to degenerate tumor stroma, thereby causing regression of the tumors.

Immunolocalization of urokinase-type plasminogen activator in adenomas and carcinomas of the colorectum

Carcinogenesis in the human colon is associated with a marked increase in the tissue content of the urokinase-type plasminogen activator (u-PA). This study was performed to determine the type of cells responsible for the u-PA increase in carcinomas of the colon and in their precursor lesions, the adenomas, by immunohistological evaluation applying monoclonal antibody 3689 directed to the beta-chain of u-PA. Normal intestinal mucosa (n = 17) showed hardly any staining of u-PA, but some lamina propria cells were faintly positive. Carcinomas (n = 17) and adenomas (n = 16) showed a considerable and comparable staining intensity of u-PA in neoplastic columnar epithelial cells, and this staining was found to be diffuse and cytoplasmic. In a majority of the neoplastic tissues the u-PA staining was found to be patchy and not related to known risk markers of malignancy such as dysplasia in the adenomas, or to prognostic determinants such as Dukes' classification or differentiation in the carcinomas. The observation of strong u-PA positive lamina propria cells in adenomas but infrequently observed in normal mucosa and carcinomas was noteworthy. u-PA staining intensity of the tissue sections was found to correlate well with the u-PA antigen level in the tissue extracts determined by ELISA (r = 0.52, P = 0.0001) but poorly with the u-PA activity determined enzymatically (r = 0.28, P = 0.05). In conclusion, the u-PA increase in neoplasia of the human colon can be attributed to an increased diffuse cytoplasmic content of u-PA in neoplastic columnar epithelial cells.

Coexisting macrophage-associated fibrin formation and tumor cell urokinase in squamous cell and adenocarcinoma of the lung tissues

Mechanisms of coagulation activation in situ were studied by means of immunohistochemical techniques applied to surgically resected primary adenocarcinomas and squamous cell carcinomas of the lung. Findings in these two histologic types were similar. Double-labeling techniques using macrophage-specific antibody together with antibody to either tissue factor, factor VII, factor X, or factor V revealed coincident staining for each of these coagulation factors on tumor-associated macrophages. Staining of tumor cells for these factors was rare and inconsistent. Both macrophages and fibroblasts in the tumor connective tissue stained for the a subunit of factor XIII. Fibrinogen was abundant throughout the tumor connective tissue, but staining for fibrin and D-dimer cross-linked sites of fibrin was restricted to areas adjacent to macrophages, indicating that thrombin was generated in association with tumor macrophages but not with tumor cells. By contrast, tumor cells stained diffusely for urokinase-type plasminogen activator and focally for thrombomodulin. These findings contrast with those reported previously for small cell carcinoma of the lung and suggest that coagulation activation in adenocarcinoma and squamous cell carcinoma of the lung may occur indirectly through activation of certain host cells such as macrophages. By contrast, tumor cell plasminogen activator may mediate certain aspects of the malignant phenotype in these tumor types.

Fibrin formation on vessel walls in hyperplastic and malignant prostate tissue

To explore mechanisms of coagulation activation in adenocarcinoma of the prostate, the occurrence and distribution of components of coagulation and fibrinolysis pathways in situ were studied by means of immunohistochemical techniques applied to frozen sections of fresh malignant and benign hyperplastic prostatic tissue obtained at transurethral resection. Fibrinogen was distributed throughout the perivascular and tumor connective tissue in both malignant and benign disease but was not present in adjacent areas of normal prostate. Antibodies specific for fibrin and D-dimer crosslink sites stained vascular endothelium focally in both malignant and benign tissues. Both neoplastic cells and benign hyperplastic glandular epithelial cells stained weakly and in a patchy distribution for tissue factor and focally for low-molecular-weight urokinase-type plasminogen activator. Focal staining of vascular endothelium was also observed for tissue plasminogen activator and plasmin-antiplasmin complex neoantigen. By contrast, no tissue staining was observed for factor VII, factor X, factor XIII "a" subunit, high-molecular-weight urokinase-type plasminogen activator, plasminogen activator inhibitors 1 to 3, protein C, and protein S. Thus, the similarity in findings between benign hyperplastic and neoplastic prostate tissue, the lack of either an intact tumor cell-associated coagulation pathway or fibrin formation, and the presence of fibrin on vascular endothelium are consistent with the concept that coagulation activation in prostatic cancer may not be due to a direct effect of the tumor cells on the clotting mechanism. Rather, such activation may be induced by a soluble tumor product that activates procoagulant activity on certain host (for example, vascular endothelial) cells. These findings, together with the lack of effect of warfarin anticoagulation on the clinical course of patients with prostatic cancer, contrast with findings in certain other tumor types and suggest that coagulation activation may not contribute to progression of adenocarcinoma of the prostate.

The first international urokinase/warfarin trial in colorectal cancer

Three hundred and forty-four patients with operable colorectal adenocarcinoma, Dukes' stage B or C, were entered into a randomized controlled trial of intraoperative and postoperative intravenous urokinase and/or long-term sodium warfarin therapy. The factorial design of the trial allowed evaluation of each therapy separately. Age, sex, Dukes' stage and cancer site were similar in the treatment groups. Using life-table methods, survival and recurrence/metastases free survival were estimated up to 6 years postoperatively. No significant effects of either therapy on these endpoints were found.