Evidence that cells from experimental tumours can activate coagulation factor X

Prognostic Impact of the Angiogenic Gene POSTN and Its Related Genes on Lung Adenocarcinoma

Background

The function of angiogenesis-related genes (ARGs) in lung adenocarcinoma (LUAD) remains poorly documented. This study was designed to reveal ARGs in LUAD and related networks.

Methods

We worked with sequencing data and clinical information pertaining to LUAD from public databases. ARGs were retrieved from the HALLMARK_ANGIOGENESIS gene set. Differential analysis and Kaplan–Meier (K–M) analysis were performed to authenticate the ARGs associated with LUAD. Weighted gene correlation network analysis was performed on the mining hub genes linked to the abovementioned genes, and functional enrichment analysis was done. Subsequently, Cox regression analyses were used to construct the prognostic gene. POSTN and microvessel density were detected using immunohistochemistry.

Results

POSTN, an ARG that was highly expressed in patients with LUAD and was closely associated with their weak overall survival was identified. Differentially expressed genes associated with POSTN were mainly enriched in entries related to the tubulointerstitial system, immune response, and epithelial cells. A positive correlation was demonstrated between POSTN expression and tumor microvessel density in LUAD. Subsequently, a prognostic gene signature was constructed and revealed that 4 genes may predict the survival of LUAD patients. Furthermore, the ESTIMATE and CIBERSORT analyses suggested that our risk scoring system may be implicated in altering the immune microenvironment of patients with LUAD. Finally, a ceRNA network was constructed based on the prognostic genes, and the regulatory networks were examined.

Conclusion

POSTN, a novel prognostic gene signature associated with ARGs, was constructed for the prognosis of patients with LUAD. This signature may alter the immune microenvironment by modulating the activation of the tubulointerstitial system, epithelial cells, and immune cells, ultimately affecting patient survival.

Thrombosis and cancer: Trousseau syndrome revisited

In this introductory chapter a story has been reviewed concerning the evolution of the concept of "cancer and thrombosis", since its first description by Armand Trousseau in 1865. From scattered reports on experimental material (tumor extracts) or on animal models of tumor/metastasis growth, through the progress of cell biology and experimental pharmacology, during the last 20 years interest has moved to clinical questions, such as: how to prevent and treat thrombosis, a frequent complication of both solid and hematologic malignancies? Has an occult cancer to be suspected in the majority of cases of idiopathic deep vein thrombosis? Do we need to prevent pharmacologically the occurrence of chemotherapy-associated thrombosis? Do anticoagulants have an impact on the natural history of some tumors? Why antiangiogenetic agents may be associated to a thrombotic risk? Presently, a continuous cross-talk between clinical results and experimental data is required to provide answers to these questions, taking advantage of a multidisciplinary approach to this old but still partially mysterious issue.

Inhibition of metastases by anticoagulants

Metastasis involves several distinct steps, including one in which the tumor cell, after entry into the bloodstream, comes to rest in a capillary located at the distant site where a metastatic tumor will ultimately form. Components of the blood-clotting pathway may contribute to metastasis by trapping cells in capillaries or by facilitating adherence of cells to capillary walls. Conceivably, anticoagulants could interfere with this step in the metastatic process. In this review, we have summarized current knowledge on the interaction of malignant cells, clotting factors, and anticoagulants. We used computerized (MEDLINE) and manual searches to identify studies done in humans, in animals, and in in vitro systems that were published in English between 1952 and 1998. We found many reports that the formation of metastatic tumors could be inhibited by heparin, a vitamin K antagonist (warfarin), and inhibitors of platelet aggregation (prostacyclin and dipyridamole). Despite these encouraging preliminary results and a compelling biochemical rationale, only limited information exists on the clinical use of anticoagulants for the prevention or treatment of metastatic cancer because there have been so few controlled and prospectively randomized studies on this topic. In view of the preliminary results, anticoagulants may hold promise for the prevention and treatment of metastases. We believe that larger controlled investigations are strongly warranted to evaluate the clinical potential of anticoagulants for the prevention and treatment of metastases in humans.

Venous thromboembolism and cancer

The association of thrombosis with malignant disease has been recognized for well over 100 years. Evidence from experimental and clinical studies indicates that the haemostatic system is involved in the growth, invasion and metastasis of tumours. Laboratory parameters of haemostasis are frequently deranged in patients with cancer and overt thrombosis is common spontaneously where it may be the first sign of malignancy or secondary to therapy. The mechanisms by which coagulation activation facilitates the malignant process remain to be completely elucidated, but it is clear that cells and proteins of the coagulation and fibrinolytic systems are involved at many steps in the processes of tumour growth and dissemination. The low-molecular-weight heparins with their well-proven safety and efficacy profiles offer unique modalities for the prevention and treatment of cancer-associated thrombosis. They may also play a role in overall mortality reduction in patients with malignant disease.

Activators of coagulation in cultured human lung-tumor cells

Tumor matrix generation and tumor cell growth are supported by coagulation processes within the tumor tissue. Activators of coagulation were searched for in suspensions of 9 permanent human squamous-cell lung-cancer (EPLC 32MI, U1752), large-cell lung-cancer (LCLC 97TMI, LCLC 103H, U1810), and small-cell lung-cancer (N-592, H-526, DMS79, 86MI) cell lines. Incubation with these cells shortened the recalcification time in normal plasma (also in the presence of antibodies against tissue factor) or coagulation-factor-VII-, VIII-, IX- or X-deficient plasmas. The activators of coagulation in the 2 most active cell lines (U1752 and LCLC 103H) were further characterized in purified systems: the cleavage of chromogenic substrates, and the generation of markers of pro-thrombin activation were assessed. Three activators of coagulation were found in intact or sonicated cell suspensions and culture supernatants: (i) a tissue factor (TF)-like activity; (ii) an activity activating factor X, which in contrast to "cancer pro-coagulant" was not inhibited by iodoacetamide; and (iii) an activity-activating pro-thrombin, which was inhibited by the serine protease inhibitor PMSF and appeared to require plasmatic co-factor(s). The heterogeneous expression of coagulation activators by lung-tumor cell lines might be of significance for tumor biology and response to therapy.

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.

Blood coagulation changes in nude mice bearing human colon carcinomas

We studied several blood coagulation parameters and tumor tissue procoagulant activity (PCA) in nude mice bearing human colorectal carcinomas (HCC). In a control group of 51 tumor-free nude mice, platelet number was 1.2 +/- 0.03 x 10(6)/microliters, thrombotest activity 90% +/- 2.6 and fibrinogen 172 +/- 11 mg/dl. The same parameters were studied in nude mice (n = 71) bearing 7 different HCC lines subcutaneously (s.c.). The results did not significantly differ from those in control mice but there was broad variability among groups of mice injected with different HCC lines, ranging from 0.36 to 2.55 x 10(6)/microliters for platelets, from 100 to 28% for thrombotest activity and from 42 to 460 mg/dl for fibrinogen. The results were significantly (p less than 0.05) different from those in the tumor-free group when each group of HCC-bearing animals was analyzed individually. A malignant HCC line that grew in the liver of nude mice (n = 24) significantly (p less than 0.001) reduced thrombotest activity (58% +/- 5.9). The PCA of tissue extracts from tumors grown s.c. in nude mice was assayed. All the HCC xenografts expressed PCA which differed significantly for the various tumor lines (from 25.5 +/- 1.9 to 2.8 +/- 0.6 unit/mg in tumor tissue). Cancer procoagulant (CP), a cysteine proteinase with a direct factor-X-activating effect, was present in different amounts (84.7 +/- 4.3 to 59.5 +/- 9.0%) in the tumors. Our results indicates that the nude mouse is a suitable model for evaluating the hemostatic changes induced by human tumors and may represent a tool for investigating the underlying biochemical mechanisms.

Factor IXi-antithrombin (IXiAT) and thrombin-antithrombin (TAT) complexes in lung cancer patients

Coagulation activation frequently occurs in cancer patients, resulting in thromboembolic complications and/or intravascular coagulation activation. The mechanisms leading to these alterations still are poorly understood. One explanation for the coagulation activation in malignant diseases is the presence of a direct factor X-activating cancer procoagulant. Coagulation activation in lung cancer patients develops at earlier stages than factor X activation; we demonstrated increased factor IXiAT complexes in addition to elevated TAT complexes. The increases of factor IXiAT complexes were not dependent upon the stage of the disease. In contrast, TAT complexes were higher in patients suffering from advanced pulmonary non-small cell carcinoma than in patients with limited disease. In conclusion, coagulation activation in pulmonary cancer patients occurs at earlier steps in the coagulation cascade than factor X activation. While this activation is not dependent upon the stage of the disease, the observation that TAT complexes showed higher elevations in patients with advanced than in those with limited pulmonary non-small cell carcinoma could be an indication of a cancer procoagulant that directly activates factor X.

Viral transformation increases vitamin K-dependent gamma-carboxylation of glutamate

Mammalian cells contain a microsomal vitamin K-dependent carboxylase activity which catalyzes the gamma-carboxylation of glutamate. While most cells have a limited ability to fully gamma-carboxylate proteins, it has been suggested that the ability of transformed cells to perform this complex post-translational modification may play a role in tumor biology. In this study, we examined the effect of transformation by adenovirus oncogenes on the ability of cells to efficiently gamma-carboxylate a vitamin K-dependent protein. Several morphologically transformed BHK-21 cell lines (BHK-Ad) were isolated following the chromosomal integration of the viral oncogenes E1A/E1B from human adenovirus type 12 (Ad12). The lines were capable of growing in soft agar and low serum and produced functional E1A as determined by promoter activation studies. Using a vector for the expression of the vitamin K-dependent recombinant human protein C (HPC), a regulator of the clotting cascade, Ad-transformed and nontransformed lines secreting rHPC were generated. The rHPC from the transformed and nontransformed cell lines displayed identical serine protease activities, and there were no apparent differences in the proteolytic processing of the proteins, although a minor difference in the proportion of each HPC glycoform was observed. However, the functional anticoagulant activity, which depends on the gamma-carboxyglutamic acid (Gla) content, was approximately 70% higher in the Ad-transformed lines. Approximately 90% of the rHPC from the Ad-transformed lines exhibited a calcium-dependent (high Gla) elution profile on anion-exchange resin, compared to only 15 to 26% from the nontransformed cell clones. By analyzing endogenous microsomal carboxylase, we determined that enzyme activity increased approximately 50% following transformation. Overall, our data demonstrate that transformation can increase the potential of a cell to efficiently gamma-carboxylate a protein and lend support to the suggested involvement of this post-translational modification in tumor cell function. Further, our results demonstrate a potential means of altering cells to enable full modification of vitamin K-dependent factors for structure/function studies and potentially for therapeutic use.

von Willebrand factor in head and neck cancer

Laboratory abnormalities in blood coagulation factors are common in patients with cancer but the significance is unknown. Twenty-eight patients with head and neck cancer were studied at the time of diagnosis. Twenty-five were advanced-stage (III or IV) patients. Levels of clotting factors, antithrombin III, and plasminogen were normal. Levels of von Willebrand factor (vWF), both antigenic and functional (ristocetin cofactor), were elevated. This group of patients were followed for a minimum of 41 months (median, 48 months). Fifteen patients died within the follow-up period. von Willebrand factor levels were significantly higher in these 15 than the 13 survivors. Extreme elevation of ristocetin cofactor (greater than 300 U/dl) was seen in six of the 15 patients who died and in none of the survivors. Plasma vWF is elevated in head and neck cancer and the level measured at the time of diagnosis may have prognostic and potentially therapeutic implications.

Factor X-activating procoagulant in normal and malignant breast tissue

Factor X-activating activity (FXAA) was determined by a chromogenic assay in normal and malignant breast tissue. FXAA was found in all tissue (n = 38) irrespective of pathology, and the activity of normal tissue was similar to that of tumours. FXAA correlated with tissue hemoglobin in normal breast (p less than 0.02) but not in tumours. FXAA was markedly reduced by aluminium hydroxide, barium citrate, anti-human factor VII, DFP, PMSF and phospholipase C, but was unaffected by iodoacetamide and mercuric chloride. It is concluded that FXAA is a serine protease with the properties of a tissue factor-factor VII complex. FXAA occurs in normal and malignant breast tissue, although the 'normal' activity may be an artefact of the homogenization process.

The coagulopathy of childhood leukemia. Thrombin activation or primary fibrinolysis?

Little information is available on the prevalence and etiology of the coagulopathy present in some children with acute leukemia at disease presentation. We studied 102 children with newly diagnosed acute leukemia (50 retrospective: Group A; and 52 prospective: Group B) with prothrombin time (PT), partial thromboplastin time (PTT), thrombin time (TT), fibrinogen (FIB), and fibrin degradation products (FDP). All patients in Group B also had assessment of thrombin activation by measurement of the crosslinked fibrin fragment, D-dimer, and of primary fibrinolysis with the B beta 1-42 peptide. Additionally, ten patients from Group B had Factors II, V, VII, and X measured, and eight of these patients had measurement of tissue factor from sonicated bone marrow cells. Thirty-two percent of Group A and 40% of Group B had totally normal coagulation studies, whereas 20% of Group A and 10% of Group B had a severe coagulopathy on disease presentation. A high percentage of both groups had elevated PT (Group A, 52%; Group B, 27%) and increased FDP (Group A, 39%; Group B, 25%). In Group B, 38% of the patients had a positive D-dimer, whereas only 4% of this prospective group had an elevated B beta 1-42 peptide (P less than 0.00001). Nine of ten patients with a positive D-dimer had low levels of one or more of the extrinsic pathway factors. Three of four patients with the highest tissue factor levels were of monocytoid leukemia cell type. These data indicate that the coagulopathy associated with acute leukemia of childhood is usually mediated by thrombin activation.

Cancer procoagulant in serum of rats during development of experimental epithelioma

The activity of cancer procoagulant (CP) during the development of Guérin epithelioma was studied in the blood of Wistar rats. Blood was collected from the carotid artery and, after clotting, proteins adsorbing on aluminum hydroxide were removed from the serum. Then procoagulant activity was determined in the test system without factor VII by means of substrate S-2222 specific for factor Xa. A statistically significant increase in the activity of CP in serum was detected, coinciding with the period of intensive tumor growth (15th-25th day of disease).

Procoagulant activity of human tumours: existence of Xa and thrombin-like activities

We have analysed 15 infiltrating duct carcinomas of the breast, 10 gastrointestinal adenocarcinomas, one each of the thyroid and larynx, and four mesenchymal tumours for the presence and the nature of procoagulant activity (PCA). The metastatic tumours had a significantly higher PCA (P = 0.01-0.001) as compared to the non-metastatic tumours in the respective groups, and almost 20-25 times the activity as compared to normal tissue (P = 0.001). Although the majority of the tumours had FVII-dependent tissue thromboplastin-like activity, some of the tumour homogenates revealed the presence of an FVII-independent PCA. Unlike the known alternate PCA, which acts via factor X activation, this PCA was factor X independent. It caused clot formation in FX-deficient plasma (six cases) and purified fibrinogen solution (four cases), indicating the presence of a Xa-like enzyme or a thrombin-like activity respectively.

Clotting activation and impairment of fibrinolysis in malignancy

Different coagulation and fibrinolysis parameters were investigated in 149 patients with metastatic and non-metastatic tumours and results were compared with those obtained in a healthy population. Results showed a significant increase of thrombin-antithrombin complexes, fibrinopeptide A (FPA) and fibrin monomers in the group of patients (p less than 0.001). There was also a significant prolongation of euglobulin lysis time (p less than 0.005) and an increase of plasminogen activator inhibitor activity (p less than 0.0001), fibrinogen degradation products (p less than 0.001), and D-dimer (p less than 0.05) in the group of patients as compared to controls; FPA levels were also increased in patients with metastases (p less than 0.005). This study demonstrates clotting activation, at the level of fibrinogen to fibrin conversion, and impairment of fibrinolysis in patients with malignancy.

Procoagulant activity of mouse transformed cells: different expression in freshly isolated or cultured cells

This study was originally designed to investigate whether there is any correlation between the type of procoagulant activity (PCA) and the tumorigenicity of transformed cells. The data obtained are relevant to this question and to defining the differences in the expression of cellular activities depending on the in vitro system used. PCA was measured and characterized in normal, immortalized, and tumorigenic mouse fibroblasts. In all the cell lines studied the activity was of tissue factor type, as established with functional, enzymatic, and immunochemical criteria. However, the PCA of cells freshly isolated from the tumors induced by tumorigenic cell lines was of cancer procoagulant type, i.e. a cysteine protease with direct factor X activator activity. The same cells, when cultured in vitro, expressed again PCA of tissue-factor type. These results suggest that either a tumor-host interaction is required for the expression of cancer procoagulant or the latter activity, produced by tumor cells under in vitro conditions, is destroyed or inactivated during the culture period. Our findings caution against defining the procoagulant activity of tumors based on experiments on cultured cells.

Factor X-activating activity in normal and malignant colorectal tissue

The factor X-activating activity (FXAA) of homogenates from human colorectal tumours and corresponding normal colonic mucosa from the same patients was assessed with a specific chromogenic substrate technique. FXAA was detected in all normal and tumour tissue tested, but was significantly higher in tumour tissue. The procoagulant activity was inhibited by DFP, but was unaffected by iodoacetamide and mercuric chloride. FXAA was largely abolished by prior incubation of both normal and tumour tissue homogenates with a rabbit anti-human factor VII serum, but was greatly enhanced by the addition of purified factor VII. FXAA was partially adsorbed on to aluminium hydroxide and almost completely abolished by treatment with barium citrate. It is concluded that the FXAA of both normal and malignant colorectal tissue is the result of tissue factor-factor VII interaction.

DMSO-induced changes in the procoagulant and fibrinolytic activity of B16 melanoma cells: influence on lung colony formation

In this study DMSO (dimethylsulphoxide) was used as a tool to test the significance of in vitro modifications of procoagulant and fibrinolytic activity of tumor cells for their in vivo metastatic ability. B16 melanoma cells were chosen as the experimental model. After four days' treatment DMSO increased both the procoagulant and fibrinolytic (plasminogen activator) activity of B16 melanoma cells in a dose-related manner. DMSO treated cells showed significantly greater lung colonizing ability than untreated cells. Our results indicate that DMSO treatment in vitro can modulate procoagulant and fibrinolytic activity and the metastatic ability of B16 melanoma cells; however a direct causal relationship between these in vitro and in vivo effects remains to be established.

Factor X-activating activity in patients with colorectal carcinoma

The ability of malignant tissue from 50 patients with colorectal carcinoma to activate blood coagulation factor X directly was compared with samples of adjacent, macroscopically normal colonic mucosa from the same patients, and tissue from four patients with non-malignant bowel disease. The resected tissue was homogenized and incubated with purified factor X and calcium ions. The subsequent generation of activated factor X was measured spectrophotometrically with a chromogenic substrate. Results were expressed as absorbance units, and as the ratio of tumour and normal activities. Factor X-activating activity (FXAA) was present in all normal and malignant tissues tested. FXAA was significantly greater (P less than 0.001) in the tumour homogenates than in the uninvolved tissue. The tumour:normal ratio was significantly (greater than 1.2) elevated in 38 patients (76 per cent). FXAA was not correlated with the degree of differentiation of the tumour, the Dukes' classification of the disease or the exact site of the tumour. There was no difference between the FXAA content of non-involved tissue from the colorectal cancer group and colonic mucosa from patients with non-malignant bowel disease. It is concluded that colorectal carcinomas contain significantly more FXAA than adjacent, non-malignant colonic mucosa from the same subject, but there is no direct evidence for a relationship between procoagulant levels and the extent of malignancy in these patients.

Untreated prostatic carcinoma is not associated with frequent thrombohemorrhagic disorders

We conducted an evaluation of the hemostatic integrity of patients with untreated cancer of the prostate. Of 60 patients analyzed retrospectively, only 1 had a mild case of disseminated intravascular coagulation, possibly associated with concomitant estrogen therapy, and in 1 patient mild deep vein thrombosis developed preoperatively, also possibly associated with multiple medications for concurrent disorders. Of 16 other patients prospectively evaluated on admission, only 1 had frankly abnormal levels of fibrinopeptide A unaccompanied by other coagulation abnormalities. Occasional individuals had minimal, negligible deviations of partial thromboplastin times, thrombin time, or antithrombin III values. In none of these patients did hemostatic complications develop during their hospital stay. These results demonstrate that although an occasional coagulation abnormality may occur in patients with cancer of the prostate (albeit with a lower incidence than in other neoplasms), this malignancy does not require increased precautions with respect to those given to the patient population at large.

Several murine metastasizing tumors possess a cysteine proteinase with cancer procoagulant characteristics

Cancer Procoagulant (CP), a cysteine proteinase which triggers blood coagulation by directly activating Factor X (FX) in the absence of Factor VII (F VII), has recently been isolated from rabbit V2 carcinoma and biochemically characterized. We have studied the procoagulant activity of tissue extracts from 4 murine experimental tumors in order to define whether or not a F VII-independent activity with cysteine proteinase characteristics was present. The tumors studied were: Lewis lung carcinoma (3LL), B16 melanoma (B16), JW sarcoma (JWS) and the M4 variant of the mFS6 fibrosarcoma (M4). Extracts from 3LL, B16 and JWS tumor initiated coagulation in both the presence and absence of F VII, their procoagulant activity was sensitive to iodoacetamide (1 mM) and mercury chloride (0.1 mM). The procoagulant of M4 extract was dependent on the presence of F VII and was not significantly affected by the cysteine proteinase inhibitors. An Ouchterlony double immunodiffusion study showed immunological cross-reactivity of all but M4 extracts to a polyclonal antibody to purified CP. The present study suggests that the procoagulant(s) present in the murine tumors 3LL, B16 and JWS are enzymatically and immunologically indistinguishable from cancer procoagulant of the rabbit V2 carcinoma.

Plasma-dependent and -independent mechanisms of platelet aggregation induced by human tumour cell lines

Tumour cell induced platelet aggregation (TCIPA) may facilitate haematogenous tumour metastasis. In this study of the aggregatory responses of human platelets to human tumour cell lines, we have found two distinct mechanisms of TCIPA. Colon carcinoma lines Colo 205 and Colo 397 produced TCIPA which was dependent upon thrombin generated through the activation of clotting factor VII, consistent with the expression of tissue factor activity by these cells. This mechanism was calcium dependent and was partially mediated by platelet ADP release as it was inhibited by apyrase. A uterine carcinosarcoma line (Colo 526) produced TCIPA by a novel mechanism which was dependent upon calcium, but was independent of thrombin generation and of the presence of plasma proteins, indicating that this aggregatory response is initiated by a direct platelet-tumour cell interaction.

Murine tumor-induced platelet aggregation and coagulation: mechanisms, inhibitors, and species differences

This study examined the platelet-aggregating and procoagulant activities of two hematogenously disseminating tumors, a mouse lymphoblastic leukemia (L5178Y) and a mouse renal adenocarcinoma (RAG). Tumor-induced human platelet aggregation was inhibited by addition of the following agents to platelet-rich plasma (PRP): a calcium channel blocker (verapamil), a chelator of divalent cations (EDTA), stimulators of adenylate cyclase (2-fluoroadenosine and forskolin), and inhibitors of cAMP phosphodiesterase (oxagrelate and papaverine). The platelet-aggregating activities of both cell lines were completely blocked by treatment of the cells with heat, sonication, phospholipase A2, and Triton X-100. These data suggest that L5178Y and RAG cell-induced human platelet aggregation are dependent on a heat-labile phospholipid component of the tumor cell membrane. L5178Y cells had greater platelet-aggregating activity in human plasma than in rat or mouse plasma, whereas RAG cells had greater procoagulant activity in rat or mouse plasma than in human plasma. The procoagulant activity of RAG cells in rat and mouse plasma was demonstrated by three lines of evidence: RAG cells induced heparinized PRP to clot; the thrombin inhibitor DAPA lengthened of the clotting time and the lag time before aggregation; and RAG cells shortened of the recalcification time of the plasma. The above data indicate that RAG cell-induced murine platelet aggregation and coagulation is dependent on thrombin generation.

Vitamin-K-dependent proteins in microsomes of primary Lewis lung tumors

Microsomes isolated from Lewis lung (LL) primary tumors raised in C57BL/6 mice have been shown to (i) contain a 4-hydroxycoumarin (warfarin)-sensitive cycle of vitamin K metabolism which is at least qualitatively similar to that of liver, and (ii) catalyze the incorporation of NaH14 CO3 into endogenous protein in a vitamin-K hydroquinone-dependent reaction to produce gamma-carboxyglutamate. As in liver microsomes, LL microsomal reduction of vitamin K 2,3-epoxide to vitamin K was greatly enhanced by exogenous dithiols such as dithiothreitol, but under identical conditions the former was 10-fold faster. The R(+) and S(-) warfarin enantiomers were highly and equally effective inhibitors of both the liver and tumor vitamin K 2,3-epoxide reductases-the average I50 against the tumor enzyme was 0.25 microM. Partially purified reductases isolated by centrifugation of sodium-cholate-treated liver and LL tumor microsomes over a discontinuous sucrose gradient were also inhibited by the sulfhydryl reagent N-ethylmaleimide following their reduction by dithiothreitol. Like the activity of the epoxide reductase, that of the gamma-carboxylase was much lower in tumor than in liver microsomes and was only detectable in microsomes isolated from tumor-bearing mice previously administered S(-) warfarin. In view of the reported inhibition of LL tumor metastasis by warfarin and diet-induced vitamin-K deficiency, vitamin-K-dependent proteins may play a role in the spread and/or subsequent growth of LL cells.

The significance of the fibrin/fibrinogen degradation product in serum of carcinoma patients with hematogenous metastasis

Fibrin/fibrinogen degradation product (FDP) was measured in 270 cases with various carcinomas. An elevation of FDP (5 micrograms/ml or more) was observed in 68 cases (25%). Of the 68 elevated FDP cases, 5 (82%) were inoperable or received nonradical resection. Forty of those 56 cases (71%) showed hematogenous metastasis. FDP in those cases which showed hematogenous metastasis was found to be due to fibrinolysis accompanied by consumption coagulopathy.

Generation of procoagulant activity by mononuclear phagocytes: optimisation of an in vitro assay

Leucocyte procoagulant activity (PCA) has previously been advocated as a useful measurement of cell-mediated immune reactivity. The assay is, however, susceptible to inter- and intra-experimental variation. This investigation identifies several factors which influence the stability and reproducibility of the test. Major factors which affect the recalcification time of plasma, include plasma lability, medium/buffer pH and both the nature and concentration of the indicator cells used in the assay. C. parvum-induced mouse peritoneal exudate cells have been used as a novel source of mononuclear phagocytes in the generation of PCA. Their sensitivity as indicator cells has been demonstrated by their responsiveness to stimulation by phytomitogen, endotoxin, and lymphokine (macrophage procoagulant-inducing factor). A simple test based on antigen-induced PCA of these cells, has provided an in vitro index of in vivo sensitisation to sheep red blood cells. Optimisation and standardisation of conditions detailed in this report for estimating PCA, renders the assay of value in monitoring lymphocyte and macrophage activation.

Isolation and characterization of cancer procoagulant: a cysteine proteinase from malignant tissue

Cancer procoagulant, a proteolytic procoagulant enzyme, has been purified from rabbit V2 carcinoma extracts by two procedures. In the first, the protein was purified by benzamidine--Sepharose affinity chromatography, gel filtration chromatography, and phenyl-Sepharose hydrophobic chromatography. Antiserum was raised against the purified protein and was used to prepare an immunoadsorbent column. In the second, tumor extracts were purified by immunoaffinity chromatography followed by p-(chloromercuri)benzoate affinity chromatography. The second procedure was substantially quicker and easier. The final product of both procedures was homogeneous on the basis of analytical sodium dodecyl sulfate--polyacrylamide gel electrophoresis and isoelectric focusing. The molecular weight was 68 000 and the isoelectric point 4.8. The proteinase activity of cancer procoagulant directly activated factor X, in the absence of factor VII, and was inhibited by 1 mM iodoacetamide and 0.1 mM mercury which are classic cysteine proteinase inhibitors. A carbohydrate analysis showed less than 1 mol of hexose or sialic acid/mol of protein. The amino acid analysis showed that serine (19.1%), glycine (18.77%), and glutamic acid (12.5%) were the prevalent amino acids. The amino acid composition of cancer procoagulant was substantially different than other known factor X activating proteinases or other cysteine proteinases including cathepsin B.

Procoagulant activity of mouse and human cultured cells following various types of transformation

The presence of fibrin deposits in the microenvironment of tumor cells has been reported repeatedly and considered to play an important role in tumor biology. Among the mechanisms by which fibrin may be deposited in tumors, procoagulant activities (PCA) of different types have been described in cancer cells. The present study was aimed at establishing whether the nature of cellular PCA was a characteristic associated with malignant transformation. PCA of normal and transformed cells was investigated on pairs of murine and human origin. The transformed counterparts were obtained after treatment with low-dose radiation, chemical carcinogen, viral infection or after in vitro spontaneous immortalization. Both before and after any type of transformation cell PCA was of the tissue thromboplastin type, identified on the basis of biological criteria: requirement of factor VII for its expression and lack of inhibition by the serine protease inhibitor diisopropylfluorophosphate (DFP). Transformed cells of murine origin showed significantly lower activity than their normal counterparts, whereas all the transformed human cell lines expressed significantly higher activity than normal. An inverse correlation between the levels of PCA and the cell density in culture was observed in all but one of the lines tested. These findings suggest that the factor X activating property described in some tumors or in transformed cells cannot be considered as a general marker of transformation.

Effect of surgery on tumor-induced accelerated coagulation in a rat carcinoma

Accelerated coagulation detected by thromboelastography has been reported in early stages of tumor growth. The present investigation was conducted to determine the changes in tumor-induced accelerated coagulation following complete and partial resection of the tumor. Male Fisher rats were divided into four groups: (1) control, (2) tumor-bearing rats, (3) complete resection, (4) partial resection. In groups 2, 3, and 4 a 2-mm3 piece of squamous cell carcinoma (NCI 11095) was implanted subcutaneously in the left flank. Seven days later blood samples were obtained from the tumor and control groups and tested on a thromboelastograph to determine the effect of the tumor on the coagulation of the hosts. Six weeks following the initial tumor implantation a sham operation was performed on group 2, complete resection on group 3, and a partial resection on group 4. After a rest period of 3 weeks blood samples were obtained from the four groups of rats and tested on a thromboelastograph. The results indicate that there is a significant acceleration of coagulation in tumor-bearing animals. The effect of surgery on this tumor-induced phenomenon depends on the type of procedure performed. Complete resection returns the coagulation status toward normal whereas sham operation or a partial resection do not. In this tumor model, hypercoagulability of the blood, therefore, indicates the presence of residual tumor.

Purification and characterization of platelet aggregating activity from tumor cells: copurification with procoagulant activity

The platelet aggregating component from murine 15091A mammary adenocarcinoma cells was purified by solubilization of activity with CHAPS (3-[(3-cholidamidopropyl)-dimethylammonio]-1-propane sulfonate), fractionation with ammonium sulfate, ion exchange chromatography on DEAE cellulose, and hydrophobic interaction chromatography on dodecyl agarose. A purification of 90-100 fold over the initial cell homogenate was achieved. SDS-PAGE of the purified material resulted in a single major band with a molecular weight of 51,000 +/- 2,000. Procoagulant activity was found to copurify with platelet aggregating activity. Reconstitution with phospholipids was necessary to obtain platelet aggregating activity and procoagulant activity. Trypsin abolished both platelet aggregating and procoagulant activities. The irreversible proteinase inhibitors phenylmethylsulfonyl fluoride, N alpha-p-tosyl-L-lysine chloromethyl ketone, iodoacetamide or phenanthroline had no effect on platelet aggregating or procoagulant activities. Platelet aggregation induced by this material was inhibited by low concentrations of the specific irreversible thrombin inhibitors, dansylarginine N-(3-ethyl-1, 5-pentanediyl) amide and D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone. This is the first report of copurification of tumor cell platelet aggregating and coagulating activities.

Hemostasis and mechanism of action of selective antimetastatic drugs in mice bearing Lewis lung carcinoma

The selective antimetastatic agents p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK), 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC) and (+/-)1,2-di(3,5-dioxopiperazin-1-yl)propane (ICRF-159) have been shown to markedly depress the formation of spontaneous hematogenous metastases in mice bearing s.c. Lewis lung carcinoma, with a mechanism unrelated to cytotoxicity for tumor cells. The effects on hemostasis of DM-COOK, DTIC and ICRF-159 have thus been examined in comparison with those of a purely cytotoxic agent, cyclophosphamide, in mice bearing i.m. Lewis lung carcinoma. The parameters considered are the number of platelets and their aggregability, prothrombin and partial thromboplastin times, plasma fibrinogen concentration and tumor cell procoagulant activity. Slight variations are caused by drug treatment in tumor-bearing mice as compared with untreated tumor-bearing controls; the pattern of effects of the selective antimetastatic agents does not differ from that of the reference cytotoxic compound used, cyclophosphamide. These data thus indicate that the effects on hemostasis of the drugs examined can contribute only marginally to their antimetastatic action, since more pronounced effects on hemostasis have been shown to be required to significantly affect metastasis formation.

Functional characterization of single-chain factor X from rat liver

14C-Labeled single-chain factor X prepared by vitamin K-dependent carboxylation in vitro was partially purified by adsorption to BaSO4 and chromatography on DEAE-Sephacel. Known activators of factor X were analyzed for their effect on the single-chain molecule. 14C-Labeled factor X antigens were recovered immunochemically from incubation mixtures and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Incubation with trypsin resulted in the generation of factor Xa clotting activity, and the 14C-labeled product migrated after reduction with an apparent molecular weight of 22,500 +/- 1500 (mean +/- 1 SD). The light chain produced by factor Xa was similar to that produced by trypsin (Mr 24,500 +/- 1500; mean +/- 1 SD). Incubation of single-chain factor X with factor VII and thromboplastin, factor IXa, or the factor X activating enzyme from Russell's viper venom gave a reducible product with a light chain of higher apparent molecular weight (Mr 37,000-38,000). Incubation with factor VII and thromboplastin also resulted in the generation of factor Xa clotting activity. Incubation of single-chain factor X with platelets resulted in the binding of about 20% of the 14C. The bound 14C-labeled factor X antigen released by freezing and thawing in the presence of EDTA was reduced to give a 14C-labeled polypeptide with Mr 31,000. Walker 256 tumor cells bound about 30% of the 14C. The bound material, after reduction, gave a 14C-labeled polypeptide with Mr 23,000.

Role of plasma, platelets, and endothelial cells in tumor metastasis

This review studies interactions of tumor cells with a particular host system which is normally responsible for hemostasis and the physiological integrity of the blood vessel luminal surface. With malignancy components of this system are frequently activated, producing abnormalities of blood coagulation, increased platelet responses, and conditions favoring tumor growth and metastasis. Activation of the clotting cascade is mediated by tumor and macrophage procoagulants, acting via Factor X or VII. Thrombin and fibrin are formed. Thrombin also interacts with platelets and the endothelium, potentiating or decreasing coagulation. Generation of thrombin or other tumor mechanisms activate platelets, leading to direct aggregation or secretion of ADP, serotonin, and/or intermediates of the arachidonate metabolism. Vascular lesions caused by tumor attack, platelet secretion, or exogenous agents promoting metastasis may also activate the hemostatic system. It is not yet fully understood how activation of the clotting system, including platelets, contributes to metastasis. Secretion of platelet products appears, however, to be heavily involved. Based on putative mechanisms of action, anticoagulants, platelet inhibitors, thrombocytopenic or vascular repairing agents have been used to control tumor spread. Results depended on the agent and experimental model of metastasis used. Except for coumarin, which was beneficial even against spontaneous metastases, other anticoagulants and platelet inhibitors, excluding perhaps Nafazatrom, gave equivocal results. Thrombocytopenic agents, however, were effective in every tumor system and with any experimental model of metastasis, indicating that platelets play a role in this process. Also consistent were the inhibitory effects of leech salivary gland extract (probably a vascular repairing agent) against lung tumor colonization promoted by ionizing radiation, cyclophosphamide, and cortisone.

Involvement of a cathepsin B-like cysteine proteinase in platelet aggregation induced by tumor cells and their shed membrane vesicles

Murine 15091A mammary adenocarcinoma cells and membrane vesicles spontaneously shed from these tumor cells in culture can induce aggregation of washed human platelets. A spectrum of proteinase inhibitors was tested for their ability to inhibit 15091A induced platelet aggregation. Of the inhibitors tested the most effective were those selective for cysteine proteinases. The effect of the spectrum of proteinase inhibitors on 15091A induced platelet aggregation was compared to the effect on cathepsin B-like cysteine proteinase activity in homogenates of 15091A tumor cells and their spontaneously shed vesicles. The results suggest that there is a correlation between activity of a cathepsin B-like proteinase in 15091A cells and vesicles and the ability of these cells and vesicles to induce aggregation of washed human platelets.

Warfarin inhibits both procoagulant activity and metastatic capacity of Lewis lung carcinoma cells. Role of vitamin K deficiency

Chronic vitamin K deficiency, either dietary or pharmacologically induced with warfarin, depressed significantly the growth of lung secondaries in a spontaneously metastasizing murine tumor, the Lewis Lung Carcinoma. This effect was associated with a marked depression of the procoagulant activity of cancer cells, which could contribute to fibrin deposition around the tumor. Cellular anticoagulation may thus be an important mechanism in the antimetastatic effect of warfarin.

Coagulant and fibrinolytic activities in the leukemic cell lysates

We attempted to examine procoagulant activity (PCA), X activator activity (XAA) and plasminogen activator activity (PlgAA) of various leukemic cell lysates: 17 acute myelocytic leukemias (AML), 4 acute promyelocytic leukemias (APL), 9 acute myelomonocytic leukemias (AMMoL), 7 chronic myelocytic leukemias (CML), 4 CML with blastic crisis, 7 T cell acute lymphocytic leukemias (ALL), 8 adult T cell leukemias (ATL), 8 null cell ALL, 6 B cell lymphocytic leukemias. Among those 70 cases, 4 APL, 4 AMMoL and 5 AML were associated with overt disseminated intravascular coagulation (DIC) and 5 T cell ALL, 7 ATL and 2 null cell ALL were associated with hypofibrinogenemia not adapted for DIC. The sample used was the lysate of 10(7) cells. PCA was measured by recalcification time of normal plasma with the cell lysate, XAA and PlgAA was measured by chromogenic substrate. APL and AML, especially those associated with overt DIC, had high PCA, and lymphocytic leukemia generally had low PCA in comparison with normal controls. Total PCA (PCA multiplied by cell count/microliter) was remarkably increased in DIC and mildly increased in ALL with hypofibrinogenemia. The change in XAA and total XAA (XAA multiplied by cell count/microliter) was not remarkable in any leukemia except for T cell ALL and null cell ALL with hypofibrinogenemia. PlgAA was high in lymphocytic leukemias with hypofibrinogenemia, APL and AMMoL with DIC. Total PlgAA (PlgAA multiplied by cell count/microliter) was high especially in T cell ALL and null cell ALL with hypofibrinogenemia. Thus it is probable that PCA is the most important factor causing DIC in myelogenous leukemia and that PlgAA is the most important factor causing hypofibrinogenemia in lymphocytic leukemia. The measurement of these activities in the leukemic cells is valuable in prediction and prevention of the hemostatic disorder in leukemia.

Inhibition of tumor cell metastasis by modulation of the vascular prostacyclin/thromboxane A2 system

The interaction between metastasizing tumor cells and the hemostatic system of the host has been implicated in successful tumor cell dissemination. Prostacyclin (PGI2) decreases metastasis from tail vein injected B16 amelanotic melanoma (B16a) cells when administered 15 min prior to tumor cells. This effect is potentiated by a phosphodiesterase inhibitor. Initial trapping of 125I Udr labelled tumor cells in pulmonary vascular beds is unaltered by PGI2 but retention time is decreased. PGI2 decreases retention time even when administered 60 min post tumor cells. Structurally unrelated thromboxane (TX) synthetase inhibitors and a TXA2 receptor antagonist also reduce metastasis from tail vein injected B16a cells. Furthermore, one inhibitor, 1-(7-carboxyheptyl)imidazole, when injected intraperitoneally reduced spontaneous metastasis from subcutaneous B16a and Lewis lung carcinoma tumors. These results suggest that selective manipulation of PGI2 and TXA2 can reduce the hematogenous spread of tumor cells.

Fibrin as a component of the tumor stroma: origins and biological significance

An association between cancer and the coagulation system was suggested by Trousseau more than a century ago and initial reports of fibrin deposition in the stroma of solid tumors date back some 25 years. However, the validity and generality of these observations have only quite recently been established, and their implications for an understanding of tumor biology, metastasis, and therapy are only now coming to be appreciated by investigators in the mainstream of cancer research. This article reviews the current status of fibrin's role in the biology of tumor growth, considering in turn: (1) the evidence that fibrin is present in tumors, the nature of such fibrin, and its relation to plasma fibronectin; (2) the mechanisms by which fibrin may come to be deposited in tumors; and (3) the potential biological and medical significance of tumor-associated fibrin deposition and degradation. Among the last are such important possibilities as a barrier function to the immune response and possible roles in angiogenesis, desmoplasia, and metastasis.

Heparin treatment of microangiopathic haemolytic anaemia associated with an experimental tumour

In rats bearing the solid Walker 256 carcinosarcoma microangiopathic haemolytic anaemia (MHA) developed during the course of tumour growth. A phase of hypercoagulability was followed by a significant decrease in plasma fibrinogen, platelet count and antithrombin III. A diminished haematocrit and a rise in plasma haemoglobin and schistocyte count were accompanied by fibrin deposits in the tumour vessels. When the rats were treated with heparin during the growth of the Walker tumour, both DIC and MHA were prevented except of the last period of the experiment. The tumour sizes, however, did not differ in the controls and the heparinized animals. There is a fair amount of evidence to suggest that the MHA was induced by a tumour-dependent DIC which was blocked by heparin over a certain time period. In contrast, the tumour growth was not modified by effective suppression of DIC and MHA.

Is the formation of fibrin a necessary event for the initiation of angiogenic responses in the chick chorioallantoic membrane?

Millipore filters belong to number of solid materials which interact with the chorioallantoic membrane (CAM) and frequently initiate local edemas sometimes accompanied by vascular responses. We observed that such reactions can completely be prevented by coating Millipore filter pieces with hydrophilic polymers (e.g. polyvinylpyrrolidone dextran) or by hydrophobic substances as liquid paraffin and vaseline. Protease inhibitors (Contrikal, epsilon-aminocaproic acid) did not prevent such reactions but increased the incidence of vascular responses. By assaying several blood components we found a relationship between the initiation of vascular responses in the CAM and the process of blood clotting. If small amounts (5 to 10 microliter) of citrated bovine or human plasma arae dropped on the CAM angiogenic responses occur as good as regularly. They are also initiated if the plasmas are recalified and small fibrin fragments are placed on the CAM. Chicken plasma, however, regularly induced such responses only in combination with bovine serum or following application of (or treatment with) fibrinolysis inhibitors. We conclude that the formation of a stable extravascular plasma clot with reduced susceptibility to fibrinolysis could be the most important precondition for the initiation of vascular responses, and that all materials, substances or biofactors capable of activating the clotting cascade should also have the capacity to induce angiogenic responses.