Increased circulating levels of thrombin-activatable fibrinolysis inhibitor in lung cancer patients

Key therapeutic targets implicated at the early stage of hepatocellular carcinoma identified through machine-learning approaches

Hepatocellular carcinoma (HCC) is the most frequent type of primary liver cancer. Early-stage detection plays an essential role in making treatment decisions and identifying dominant molecular mechanisms. We utilized machine learning algorithms to find significant mRNAs and microRNAs (miRNAs) at the early and late stages of HCC. First, pre-processing approaches, including organization, nested cross-validation, cleaning, and normalization were applied. Next, the t-test/ANOVA methods and binary particle swarm optimization were used as a filter and wrapper method in the feature selection step, respectively. Then, classifiers, based on machine learning and deep learning algorithms were utilized to evaluate the discrimination power of selected features (mRNAs and miRNAs) in the classification step. Finally, the association rule mining algorithm was applied to selected features for identifying key mRNAs and miRNAs that can help decode dominant molecular mechanisms in HCC stages. The applied methods could identify key genes associated with the early (e.g., Vitronectin, thrombin-activatable fibrinolysis inhibitor, lactate dehydrogenase D (LDHD), miR-590) and late-stage (e.g., SPRY domain containing 4, regucalcin, miR-3199-1, miR-194-2, miR-4999) of HCC. This research could establish a clear picture of putative candidate genes, which could be the main actors at the early and late stages of HCC.

Molecular mechanisms investigation for liver metastasis of colorectal cancer by combined bioinformatic gene expression profile analysis

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers worldwide. As the molecular mechanism for liver metastasis of CRC has not yet been completely discovered, identification of hub genes and pathways of this disease is of importance for revealing potential molecular mechanism of colorectal cancer progression. This study aimed to identify potential biomarkers and survival analysis of hub genes for CRC treatment.

METHODS

The differentially expressed genes (DEGs) between colorectal cancer liver metastasis and primary tumor were screened using microarray data from two datasets GSE179979, GSE144259 obtained from the Gene Expression Omnibus (GEO) database. Gene ontology (GO) and KEGG pathway enrichment analyses were performed for DEGs using DAVID database, the protein-protein interaction (PPI) network was constructed using the Cytoscape software, and module analysis was performed using MCODE. Then, overall survival (OS), progression free interval (PFI) and disease specific survival (DSS) analysis of hub genes was performed by using TCGA database. The correlations between hub genes and clinical values were validated through CRN and immunohistochemistry (IHC) stain.

RESULTS

A total of 64 DEGs were obtained, KEGG pathway analysis showed that the significant pathways included PPAR signaling pathway, Complement and coagulation cascades. Four hub genes (ITIH2, ALB, CPB2, HGFAC) and two biomarkers (CPB2, HGFAC) with significantly prognostic values were verified by Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) cohort.

CONCLUSIONS

 CPB2 and HGFAC may serve as new biomarkers in diagnosing liver metastasis of CRC or potential drug target.

Comprehensive analysis for clarifying transcriptomics landscapes of spread through air spaces in lung adenocarcinoma

Patients with spread through air spaces (STAS) have worse postoperative survival and a higher recurrence rate in lung adenocarcinoma, even in the earliest phases of the disease. At present, the molecular pathogenesis of STAS is not well understood. Therefore, to illustrate the underlying pathogenic mechanism of STAS, we accomplished a comprehensive analysis of a microarray dataset of STAS. Differential expression analysis revealed 841 differentially expressed genes (DEGs) between STAS_positive and STAS_negative groups. Additionally, we acquired two hub genes associated with survival. Gene set variation analysis (GSVA) confirmed that the main differential signaling pathways between the two groups were hypoxia VHL targets, PKC, and pyrimidine metabolism pathways. Analysis of immune activity showed that the increased expression of MHC-class-Ⅰ was observed in the STAS_positive group. These findings provided novel insights for a better knowledge of pathogenic mechanisms and potential therapeutic markers for STAS treatment.

Primary tumor and metastasis-sectioning the different steps of the metastatic cascade

Patients with lung cancer in the majority die of metastases. Treatment options include surgery, chemo- and radiotherapy, targeted therapy by tyrosine kinase inhibitors (TKIs), and immuno-oncologic treatment. Despite the success with these treatment options, cure of lung cancer is achieved in only a very small proportion of patients. In most patients’ recurrence and metastasis will occur, and finally kill the patient. Metastasis is a multistep procedure. It requires a change in adhesion of tumor cells for detachment from their neighboring cells. The next step is migration either as single cells [epithelial-mesenchymal transition (EMT)], or as cell clusters (hybrid-EMT or bulk migration). A combination of genetic changes is required to facilitate migration. Then tumor cells have to orient themselves along matrix proteins, detect oxygen concentrations, prevent attacks by immune cells, and induce a tumor-friendly switch of stroma cells (macrophages, myofibroblasts, etc.). Having entered the blood stream tumor cells need to adapt to shear stress, avoid being trapped by coagulation, but also use coagulation in small veins for adherence to endothelia, and express homing molecules for extravasation. Within a metastatic site, tumor cells need a well-prepared niche to establish a metastatic focus. Tumor cells again have to establish a vascular net for maintaining nutrition and oxygen supply, communicate with stroma cells, grow out and set further metastases. In this review the different steps will be discussed with a focus on pulmonary carcinomas. The vast amount of research manuscripts published so far are not easy to analyze: in most reports’ single steps of the metastatic cascade are interpreted as evidence for the whole process; for example, migration is interpreted as evidence for metastasis. In lung cancer most often latency periods are shorter, in between 1–5 years. In other cases, despite widespread migration occurs, tumor cells die within the circulation and do not reach a metastatic site. Therefore, migration is a requisite, but does not necessarily predict metastasis. The intention of this review is to point to these different aspects and hopefully provoke research directed into a more functional analysis of the metastatic process.

Fibrinolysis in patients with chemotherapy-induced thrombocytopenia and the effect of platelet transfusion

Essentials Bleeding in chemotherapy induced thrombocytopenia (CIT) might be influenced by hyperfibrinolysis. t-PA-thromboelastography is a fast and reliable assay for hyperfibrinolysis in CIT patients. Clots of CIT patients are more susceptible to t-PA induced lysis compared to healthy individuals. Besides platelets, other factors are likely to influence clot lysis in CIT patients.

BACKGROUND

Bleeding events in chemotherapy-induced thrombocytopenic (CIT) patients with similar platelet counts might be influenced by changes in clot lysis potential.

OBJECTIVES

To investigate, in an observational study, thromboelastographic lysis parameters, alterations in clot strength and susceptibility to clot lysis in CIT patients. To identify factors associated with fibrinolytic profiles, and to evaluate the effects of platelet transfusions.

METHODS

Independent determinants of tissue-type plasminogen activator (t-PA)-ROTEM lysis parameters were identified with multivariable linear regression. Clot formation, strength and lysis parameters were compared with the results of healthy individuals. Characteristics of CIT patients with and without hyperfibrinolytic profiles were compared. t-PA-ROTEM results before, 1 hour after and 24 hours after platelet transfusion were compared.

RESULTS

A total of 72 consecutive CIT patients were included. t-PA-ROTEM lysis parameters correlated with changes in fibrinolytic proteins. Clot formation time was longer, maximum clot firmness was weaker and lysis times were shorter than in healthy individuals. CIT patients had low plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor levels, and 40% showed hyperfibrinolytic profiles. Platelet transfusions resulted in less hyperfibrinolytic profiles in many, but not all CIT patients. Patients without hyperfibrinolytic profiles had higher fibrinogen, factor VIII and α2 -antiplasmin levels.

CONCLUSIONS

t-PA-ROTEM can be used as a fast and reliable assay to detect hyperfibrinolytic profiles in CIT patients. CIT patients have weaker clots, which are more susceptible to clot lysis, than healthy individuals. Besides platelets, other factors are likely to influence clot susceptibility to fibrinolysis in CIT patients. The impact of a hyperfibrinolytic t-PA-ROTEM profile on bleeding remains to be investigated.

IL-10 correlates with the expression of carboxypeptidase B2 and lymphovascular invasion in inflammatory breast cancer: The potential role of tumor infiltrated macrophages

Pro-carboxypeptidase B2 (pro-CPB2) or thrombin-activatable fibrinolysis inhibitor (TAFI) is a glycoprotein encoded by the CPB2 gene and deregulated in several cancer types, including breast cancer. Thrombin binding to thrombomodulin (TM), encoded by THBD, is important for TAFI activation. CPB2 gene expression is influenced by genetic polymorphism and cytokines such as interleukin 10 (IL-10). Our previous results showed that tumor infiltrating monocytes/macrophages (CD14⁺/CD16⁺) isolated from inflammatory breast cancer (IBC) patients' secrete high levels of IL-10. The aim of the present study is to test genetic polymorphism and expression of CPB2 in healthy breast tissues and carcinoma tissues of non-IBC and IBC patients. Furthermore, to investigate whether IL-10 modulates the expression of CPB2 and THBD in vivo and in-vitro. We tested CPB2 Thr325Ile polymorphism using restriction fragment length polymorphism, (RFLP) technique in healthy and carcinoma breast tissues. The mRNA expression of CPB2, THBD and IL10 were assessed by RT-qPCR. Infiltration of CD14⁺ cells was assessed by immunohistochemistry. In addition, we investigated the correlation between infiltration of CD14⁺ cells and expression of IL10 and CPB2. Furthermore, we correlated IL10 expression with the expression of both CPB2 and THBD in breast carcinoma tissues. Finally, we validated the role of recombinant IL-10 in regulating the expression of CPB2 and THBD using different breast cancer cell lines. Our results showed that CPB2 genotypes carrying the high-risk allele [Thr/Ile (CT) and Ile/Ile (TT)] were more frequent in both IBC and non-IBC patients compared to control group. CPB2 genotypes did not show any statistical correlation with CPB2 mRNA expression levels or patients' clinical pathological properties. Interestingly, CPB2 and IL10 expression were significantly higher and positively correlated with the incidence of CD14⁺ cells in carcinoma tissues of IBC as compared to non-IBC. On the other hand, THBD expression was significantly lower in IBC carcinoma versus non-IBC tissues. Based on molecular subtypes, CPB2 and IL10 expression were significantly higher in triple negative (TN) as compared to hormonal positive (HP) carcinoma tissues of IBC. Moreover, CPB2 expression was positively correlated with presence of lymphovascular invasion and the expression of IL10 in carcinoma tissues of IBC patients. Furthermore, recombinant human IL-10 stimulated CPB2 expression in SUM-149 (IBC cell line) but not in MDA-MB-231 (non-IBC cell line), while there was no significant effect THBD expression. In conclusion, carcinoma tissues of IBC patients are characterized by higher expression of CPB2 and lower expression of THBD. Moreover, CPB2 positively correlates with IL10 mRNA expression, incidence of CD14⁺ cells and lymphovascular invasion in IBC patients. IL-10 stimulated CPB2 expression in TN-IBC cell line suggests a relevant role of CPB2 in the aggressive phenotype of IBC.

Suppression of TAFI by siRNA inhibits invasion and migration of breast cancer cells

Human thrombin activatable fibrinolysis inhibitor (TAFI), also known as carboxypeptidase B2 (CPB2), is a procarboxypeptidase enzyme. The purpose of the present study was to observe the expression of TAFI in breast cancer (BC) and breast cancer cell (BCC) lines and to investigate the effect of TAFI suppression by small interfering (si)RNA gene silencing on invasion and migration of BCC lines. A significant increase in TAFI level was identified by immunohistochemical analysis in BC tissues compared with normal breast tissues. TAFI suppression also inhibited cell viability, invasion and migration ability as demonstrated by MTT, Transwell chamber, and wound scratch assays, respectively (P<0.05). The data suggested that suppression of TAFI by siRNA inhibits invasion and migration of breast cancer cells and that TAFI may be a new target for breast cancer therapy.

Determinants of hypofibrinolysis in patients with digestive tract cancer

Introduction

Recently, we demonstrated that digestive tract cancer (DTC) is associated with reduced fibrin clot permeability and impaired fibrinolysis.

Aim

We investigated determinants of fibrinolysis in DTC patients.

Material and methods

In 44 consecutive patients with DTC and 47 controls matched for age, sex, and cardiovascular risk, we evaluated fibrinolysis proteins, platelet activation markers, thrombin formation, together with plasma clot lysis time assays in the absence (CLT) and presence of carboxypeptidase potato inhibitor (CLT CPI) that blocks thrombin activatable fibrinolysis inhibitor (TAFI).

Results

In the DTC group CLT (by 22.3%) and CLT CPI (by 27.4%) were longer compared with controls. The DTC patients had higher plasma fibrinolysis inhibitors, plasminogen activator inhibitor 1 (PAI-1) (by 18.2%), TAFI activity (by 17.3%), and antigen (by 11.2%). The patients had markedly increased platelet markers – soluble CD40 ligand (by 338%) and P-selectin (by 97%), together with von Willebrand factor (vWF) antigen (by 61%). Thrombin-antithrombin complexes (TAT) (by 48.7%) and soluble thrombomodulin (sTM) (by 17.2%) were also increased in the DTC group (all p < 0.05). Patients with high-grade tumours (n = 26) compared with remainders (n = 18) had longer CLT, higher tissue-type plasminogen activator antigen, both TAFI antigen and activity levels, vWF, and sTM. Multiple regression analysis after adjustment for potential confounders showed that independent predictors of CLT in DTC patients were TAT, TAFI activity, and vWF. The only independent predictor of CLT CPI was TAT.

Conclusions

Hypofibrinolysis in DTC patients is largely driven by enhanced thrombin generation, TAFI, and endothelial injury.

Data supporting the structural and functional characterization of Thrombin-Activatable Fibrinolysis Inhibitor in breast cancer

The data in this paper is related to the research article entitled “Thrombin-activatable fibrinolysis inhibitor Thr325Ile polymorphism and plasma level in breast cancer: A pilot study” (Fawzy et al., 2015) [1]. Many emerging studies have begun to unravel the pathophysiologic role of the fibrinolytic system in breast cancer (BC) progression (Zorio et al., 2008) [2]. Activation of the fibrinolytic plasminogen/plasmin system results in degradation of protein barriers, thereby mediating cell migration essential for tumor growth, angiogenesis, and dissemination (Castellino and Ploplis, 2005) [3]. In the current study, in silico data analysis of Thrombin-Activatable Fibrinolysis Inhibitor (TAFI) gene and protein has been done. Data have been retrieved from several databases mentioned in details in the text. Determination and analysis of the structural and functional impact of TAFI and its expression could help elucidate the contribution of the TAFI pathway to acquired hemostatic dysfunction and will form the basis of potential therapeutic strategies to manipulate this pathway. An inhibition of TAFI (e.g. by FXI inhibitors) will offer the therapeutic possibilities to improve the decreased fibrinolysis and increase the efficiency of fibrinolytic therapy in thrombotic disorders including cancer.

Thrombin-activatable fibrinolysis inhibitor Thr325Ile polymorphism and plasma level in breast cancer: A pilot study

This study aimed to investigate thrombin-activatable fibrinolysis inhibitor (TAFI) Thr325Ile polymorphism and TAFI antigen (Ag) levels in breast cancer (BC) in the Egyptian population to clarify their role in relation to BC. A group of 300 females was recruited in this study; of these 150 unrelated patients with different stages of BC and 150 age-matched healthy controls. Plasma TAFI Ag was measured by ELISA and TAFI Thr325Ile (rs1926447) polymorphism was genotyped using TaqMan single nucleotide polymorphism (SNP) genotyping assay. The results showed the genotypes of the minor allele; Thr/Ile (CT) and Ile/Ile (TT) were significantly more frequent in patients compared to control group (50.0% and 22.0% vs. 42.0% and 13.3%, respectively) and were also associated with BC susceptibility [OR = 1.9 and 2.6; 95% CI: (1.1–3.3) and (1.3–5.5), respectively P = 0.01]. Ile325 allele carriers were more frequent in cases than in controls (47.0% vs. 34.0%) [OR = 1.7, (95% CI = 1.2–2.4), P = 0.001]. However, TAFI Thr325Ile polymorphism was not associated with BC stage or other clincopathological characteristics. TAFI Ag levels were correlated with advanced stages of BC, poor prognosis and risk of recurrence (P = 0.02, P = 0.04 and P  < 0.001, respectively) and Thr325Ile SNP was significantly correlated with TAFI antigen levels with the C/C genotype corresponding to the highest and the T/T genotype to the lowest TAFI antigen levels (P < 0.001) in the study groups. In conclusion, this study showed for the first time that TAFI Thr325Ile polymorphism could have a contribution to BC susceptibility in our population. Furthermore, high TAFI plasma levels may serve as a predictor of poor prognosis in patients with BC.

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TAFI Thr325Ile polymorphism associated with breast cancer in studied population

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TAFI Thr325Ile polymorphism was significantly correlated with TAFI antigen levels.

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High TAFI antigen levels were correlated with advanced stages of breast cancer.

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High TAFI plasma level could be used to recognize tumor prognosis and risk of recurrence.

Tissue-type plasminogen activator-induced fibrinolysis is enhanced in patients with breast, lung, pancreas and colon cancer

Although cancer-mediated changes in hemostatic proteins unquestionably promote hypercoagulation, the effects of neoplasia on fibrinolysis in the circulation are less well defined. The goals of the present investigation were to determine if plasma obtained from patients with breast, lung, pancreas and colon cancer was less or more susceptible to lysis by tissue-type plasminogen activator (tPA) compared to plasma obtained from normal individuals. Archived plasma obtained from patients with breast (n = 18), colon/pancreas (n = 27) or lung (n = 19) was compared to normal individual plasma (n = 30) using a thrombelastographic assay that assessed fibrinolytic vulnerability to exogenously added tPA. Plasma samples were activated with tissue factor/celite, had tPA added, and had data collected until clot lysis occurred. Additional, similar samples had potato carboxypeptidase inhibitor added to assess the role played by thrombin-activatable fibrinolysis inhibitor in cancer-modulated fibrinolysis. Rather than inflicting a hypofibrinolytic state, the three groups of cancers demonstrated increased vulnerability to tPA (e.g. decreased time to lysis, increased speed of lysis, decreased clot lysis time). However, hypercoagulation manifested as increased speed of clot formation and strength compensated for enhanced fibrinolytic vulnerability, resulting in a clot residence time that was not different from normal individual thrombi. In sum, enhanced hypercoagulability associated with cancer was in part diminished by enhanced fibrinolytic vulnerability to tPA.

Components of the Plasminogen-Plasmin System as Biologic Markers for Cancer

Members of the plasminogen-plasmin (PP) system participate in many physiologic functions. In particular, uPA, its receptor (uPAR) and its inhibitor PAI-1 play an important role in cell migration, cell proliferation and tissue remodeling. Through a number of interactions, these components of the PP system are also involved in the pathogenesis of many diseases. In cancer, they modulate the essential processes of tumor development, growth, invasion and metastasis as well as angiogenesis and fibrosis. Thus, quantification of uPA, uPAR and PAI-1 in tumors and, in some cases in the circulating blood, became of potential value in the prognostication of many types of cancer. These include cancer of the breast, stomach, colon and rectum, esophagus, pancreas, glioma, lung, kidney, prostate, uterine cervix, ovary, liver and bone. Published data are reviewed in this chapter. Clinical validation of the prognostic value has also been made, particularly in cancer of the breast. Inclusion of these biomarkers in the risk assessment of cancer patients is now considered in the risk-adapted management in carcinoma of the breast. Factors limiting its broader use are discussed with suggestions how these can be overcome. Hopefully the use of these biomarkers will be applied to other types of cancer in the near future.

Is there any role of thrombin activatable fibrinolysis inhibitor in the development of a hypercoagulable state in gastric cancer

Background

The purpose of this study was to investigate plasma levels of thrombin activatable fibrinolysis inhibitor (TAFI) and TAFI’s relationship with coagulation markers (prothrombin fragment 1 + 2) in gastric cancer patients.

Methods

Thirty-three patients with gastric adenocarcinoma and 29 healthy control subjects were prospectively enrolled in the study. Patients who had a history of secondary malignancy, thrombosis related disease, oral contraceptive use, diabetes mellitus, chronic renal failure or similar chronic metabolic disease were excluded from the study. A fasting blood sample was drawn from patients to determine the plasma levels of TAFI and Prothrombin Fragment 1 + 2 (F 1 + 2). In addition, data on patient age, sex, body mass index (BMI) and stage of disease were recorded. The same parameters, except stage of disease, were also recorded for the control group. Subsequently, we assessed the difference in the levels of TAFI and F 1 + 2 between the patient and control groups. Moreover, we investigated the relation of TAFI and F 1 + 2 levels with age, sex, BMI and stage of disease in the gastric cancer group.

Results

There were no statistical differences in any demographic variables (age, gender and BMI) between the groups (Table 1). The mean plasma TAFI levels of the gastric cancer group (69.4 ± 33.1) and control group (73.3 ± 27.5) were statistically similar (P = 0.62). The mean plasma F 1 + 2 level in the gastric cancer group was significantly higher than for those in the control group (549.7 ± 325.3 vs 151.9 ± 67.1, respectively; P < 0.001). In the gastric cancer group, none of the demographic variables (age, gender and BMI) were correlated with either TAFI or F 1 + 2 levels. Also, no significant associations were found between the stage of the cancer and either TAFI or F 1 + 2 levels.

Conclusion

In our study, TAFI levels of gastric cancer patients were similar to healthy subjects. The results of our study suggest that TAFI does not play a role in pathogenesis of the hypercoagulable state in gastric cancer patients.

Thrombin activatable fibrinolysis inhibitor and thrombin-antithrombin-III-complex levels in patients with gastric cancer

The relation between cancer and coagulation is the subject of investigation since a relation between tumor and thrombosis has been determined. Antithrombin III is an important thrombin inhibitor, and increased thrombin-antithrombin (TAT) complex levels activate coagulation. Activated thrombin activatable fibrinolysis inhibitor (TAFI) inhibits the conversion of plasminogen to plasmin. In addition, it directly inactivates plasmin. Defective fibrinolysis increases the risk of thrombosis. In this study, we evaluated homeostatic parameters, TAFI, and TAT levels in patients with gastric cancer applying to the medical oncology outpatient clinic. Fifty-two patients and 35 healthy controls were included. ELISA was used to measure TAFI and TAT complex levels. These were statistically higher in the patient group (p < 0.05 and p = 0.001, respectively). D-dimer levels were higher in stage IV (p = 0.05). Correlations between lymph nodes and TAFI and TAT levels were examined. Weak but positive correlation between lymph nodes and TAFI was detected (R = 0.452, p = 0.027). TAFI and TAT levels were evaluated using relative operating characteristic analysis to differentiate the disease. TAT was more specific than TAFI according to this analysis (TAFI area under curve (AUC), 0.676; TAT AUC, 0.874). Thrombotic events and bleeding disorders need to be borne in mind in gastric cancer. This situation is due to the impairment of the balance between coagulation and fibrinolysis. Further studies are now needed to evaluate the effects of TAFI and TAT on survey and prognosis as well as the potential of these parameters as tumor markers for gastric cancer.

Activated thrombin activatable fibrinolysis inhibitor (TAFIa) is associated with inflammatory markers in inflammatory bowel diseases TAFIa level in patients with IBD

BACKGROUND

Thrombin activatable fibrinolysis inhibitor (TAFI) has been reported to be involved in the pathogenesis and progression of inflammatory bowel disease (IBD). Activated TAFI (TAFIa) attenuates fibrinolysis by cleaving C-terminal lysine residues thus down-regulating plasminogen activation. To date, no reports on TAFIa in IBD have been published.

METHODS

Plasma levels of TAFIa were measured using a functional assay in 55 consecutive patients with ulcerative colitis (UC) and 50 with Crohn's disease (CD). Associations of TAFIa with disease activity, hemostatic variables and inflammatory markers were assessed.

RESULTS

Plasma TAFIa was higher in CD patients than in those with UC. The disease activity correlated positively with TAFIa levels in the UC group, but not in the CD group. In UC patients, there were positive correlations of TAFIa with white blood cells, C-reactive protein and fibrinogen and an inverse correlation with albumin. In the CD group, a positive correlation was shown for C-reactive protein, fibrinogen and platelet count, while a negative correlation was noted for albumin.

CONCLUSIONS

This study is the first to show that TAFIa is increased in CD patients compared with UC and its levels are associated with inflammatory markers in both forms of IBD. These findings fit in the hypothesis that TAFIa may be a marker of active IBD, and in particular of active UC.

Venous thromboembolism in patients with cancer and its relationship to the coagulation cascade and vascular endothelial growth factor

Venous thromboembolism (VTE) is a well-recognized problem in malignancy. Patients with cancer who have VTE have a worse prognosis than other patients with cancer. Hypercoagulability in patients with cancer is related to malignancy itself and its treatment. These patients have multiple risk factors for thromboembolism, such as being immobilized, having central venous catheters, and receiving chemoradiation therapy. Cancer procoagulant, tissue factor, factor VIII, and thrombin have important roles in causing cancer-associated thromboembolism. Tumors require neovascularization for delivering oxygen and other nutrients. Therefore, angiogenesis facilitates tumor growth, invasion, and metastasis. New blood vessels formed by angiogenesis are thrombogenic. Hypercoagulability and tumor growth are closely related. Vascular endothelial growth factor (VEGF) is a proangiogenic factor that may also cause VTE in patients with cancer. The relationship between cancer, angiogenesis, VEGF, and thrombosis is reviewed herein. Studies are ongoing to enhance our understanding of this complex interaction.

Thrombin-activatable fibrinolysis inhibitor in breast cancer patients

OBJECTIVE

To evaluate the levels of thrombin-activatable fibrinolysis inhibitor (TAFI) activity and also its relationship with other homeostasis markers in breast cancer patients.

SUBJECTS AND METHODS

Forty-two female patients with breast cancer and 24 healthy women (controls) were enrolled in the study and fasting blood samples of all cases were drawn from a large antecubital vein for assay of TAFI and other homeostasis tests.

RESULTS

The TAFI levels were 79.5 ± 15.5 and 39.3 ± 12.1 in patients and controls, respectively, and the difference was statistically significant (p < 0.001). In the patient group, the serum fibrinogen level was 504.9 ± 224.8, while in the control group it was 393.9 ± 100.5, and the difference was also statistically significant (p < 0.001).

CONCLUSION

The data showed that increased levels of TAFI are a contributing factor of thrombotic disorders in breast cancer patients.

High incidence of tumors in diabetic thrombin activatable fibrinolysis inhibitor and apolipoprotein E double-deficient mice

BACKGROUND

Activation of the complement system has been implicated in tumor growth. The antifibrinolytic protein, activated thrombin-activatable fibrinolysis inhibitor (TAFIa), can modulate the activation of the complement system by inactivating the anaphylatoxins C3a and C5a. The apolipoprotein-E (ApoE) genotype has been associated with carcinogenesis.

OBJECTIVE

The aim of this study was to evaluate whether TAFIa can affect the development of cancer in the ApoE-deficient mouse model.

METHODS

TAFI and ApoE double-knockout mice were generated. A group of mice was treated with the diabetogenic and carcinogenic compound streptozotocin (stz). Mice treated with saline, single knockout mice and wild-type (wt) mice served as controls.

RESULTS

Six months after treatment with stz, mice were sacrificed. Hepatic tumors were found in male double-knockout mice treated with stz but none was found in control animals that were not treated with stz or in single knockout of ApoE or wt animals. There was no significant difference in coagulation system activation between the groups of mice. The plasma concentrations of C5a, factor D and transforming growth factor-β1 were increased in TAFI/ApoE double-deficient mice treated with stz compared with the mice of the same genotype treated with saline.

CONCLUSION

Apo-E deficiency alone was not associated with tumors but the lack of TAFI appears to make the mice permissive for tumor formation in ApoE mice.

Biochemical characterization of bovine plasma thrombin-activatable fibrinolysis inhibitor (TAFI)

Background

TAFI is a plasma protein assumed to be an important link between coagulation and fibrinolysis. The three-dimensional crystal structures of authentic mature bovine TAFI (TAFIa) in complex with tick carboxypeptidase inhibitor, authentic full lenght bovine plasma thrombin-activatable fibrinolysis inhibitor (TAFI), and recombinant human TAFI have recently been solved. In light of these recent advances, we have characterized authentic bovine TAFI biochemically and compared it to human TAFI.

Results

The four N-linked glycosylation sequons within the activation peptide were all occupied in bovine TAFI, similar to human TAFI, while the sequon located within the enzyme moiety of the bovine protein was non-glycosylated. The enzymatic stability and the kinetic constants of TAFIa differed somewhat between the two proteins, as did the isoelectric point of TAFI, but not TAFIa. Equivalent to human TAFI, bovine TAFI was a substrate for transglutaminases and could be proteolytically cleaved by trypsin or thrombin/solulin complex, although small differences in the fragmentation patterns were observed. Furthermore, bovine TAFI exhibited intrinsic activity and TAFIa attenuated tPA-mediated fibrinolysis similar to the human protein.

Conclusion

The findings presented here suggest that the properties of these two orthologous proteins are similar and that conclusions reached using the bovine TAFI may be extrapolated to the human protein.

The role of plasminogen-plasmin system in cancer

Components of the plasminogen-plasmin system participate in a wide variety of physiologic and pathologic processes, including tumor growth, invasion and metastasis, through their effect on angiogenesis and cell migration. These components are found in most tumors and their expression not only signifies their function but also carries a prognostic value. Their expression is in turn modulated by cytokines and growth factors, many of which are up-regulated in cancer. Though both tPA and uPA are expressed in tumor cells, uPA with its receptor (uPAR) is mostly involved in cellular functions, while tPA with its receptor Annexin II on endothelial surface, regulates intravascular fibrin deposition. Among the inhibitors of fibrinolysis, PAI-1 is a major player in the pathogenesis of many vascular diseases as well as in cancer. Therapeutic interventions, either using plasminogen activators or experimental inhibitor agents against PAI-1, have shown encouraging results in experimental tumors but not been verified clinically.

The 1040C/T polymorphism influencing thermal stability and activity of thrombin activatable fibrinolysis inhibitor is associated with risk for oral cancer

No studies thus far have investigated the contribution of thrombin activatable fibrinolysis inhibitor (TAFI) to oral oncogenesis. We studied the activity-related 1040C/T polymorphism in 150 patients with oral cancer and 138 healthy controls matched by age, gender, and ethnicity. The increased-activity T allele frequency was significantly reduced in patients compared with controls (28.7% vs. 37.0%, P < 0.05). T/T homozygotes had about half the probability of developing oral cancer (O.R. 0.39, 95%C.I. 0.13-1.14), while no significant difference was observed in C/T heterozygotes. The observed prophylactic effect of increased TAFI activity might result from reduction of plasmin and inhibition of extracellular matrix dissolution.

Quantification of the effects of thrombin activatable fibrinolysis inhibitor and α2-antiplasmin on fibrinolysis in normal human plasma

Two major proteins that inhibit fibrinolysis include thrombin activatable fibrinolysis inhibitor (TAFI) and alpha2-antiplasmin. Our goal was to quantify the contribution of TAFI and alpha2-antiplasmin to antifibrinolytic defenses with thrombelastography. Plasma activated with tissue factor/kaolin was subjected to fibrinolysis with tissue-type plasminogen activator (100 U/ml). Prior to activation, TAFI activity was inhibited with either potato carboxypeptidase inhibitor (25 microg/ml) or an anti-TAFI antibody, and alpha2-antiplasmin activity was inhibited with an anti-alpha2-antiplasmin antibody. Data were collected for 30 min, with the time of onset and rate of fibrinolysis determined. Compared with uninhibited samples, TAFI inhibition significantly (P < 0.05) decreased the time of onset of fibrinolysis by 70% and increased the rate of lysis by 70%. There was no difference between potato carboxypeptidase inhibitor and anti-TAFI antibody inhibition. Inhibition of alpha2-antiplasmin resulted in a significantly (P < 0.05) decreased time of onset (85%) and increased the rate of lysis (557%) compared with uninhibited samples. Inhibition of alpha2-antiplasmin activity resulted in a significantly (P < 0.05) greater fibrinolytic response than TAFI inhibition. In conclusion, utilization of standard inhibitors and thrombelastography permitted quantification of the effects of TAFI and alpha2-antiplasmin on fibrinolysis in plasma. Future investigation of diseases involving hypofibrinolysis (e.g. left ventricular assist devices) could be conducted using this assay system.

Curiouser and curiouser: recent advances in measurement of thrombin-activatable fibrinolysis inhibitor (TAFI) and in understanding its molecular genetics, gene regulation, and biological roles

The thrombin-activatable fibrinolysis inhibitor (TAFI) pathway defines a novel molecular connection between blood coagulation and both fibrinolysis and inflammation. TAFI is a plasma zymogen that can be activated by thrombin, the thrombin-thrombomodulin complex, or plasmin. The activated form of TAFI (TAFIa) attenuates fibrinolysis by removing the carboxyl-terminal lysine residues from partially degraded fibrin that mediate positive feedback in the fibrinolytic cascade. A role for TAFIa in modulating inflammation is suggested by the ability of this enzyme to down-regulate pericellular plasminogen activation and to inactivate the inflammatory peptides bradykinin and the anaphylatoxins C3a and C5a. The focus of this review is on recent advances in the clinical measurement of the TAFI pathway in human subjects and what this has revealed in terms of the molecular genetics of TAFI, the biological variation in plasma TAFI antigen levels, potential regulators of expression of the gene encoding TAFI, and the TAFI pathway as a risk factor for the development of vascular diseases. Although this field is in its infancy, much recent progress has been made and the available data suggest that the TAFI pathway is an intriguing new player in a variety of physiological and pathophysiological contexts.