The role of the hemostatic system in tumor growth, metastasis, and angiogenesis: tissue factor is a bifunctional molecule capable of inducing both fibrin deposition and angiogenesis in cancer

Combining KRAS gene status with preoperative D‑dimer levels as a predictive marker of venous thromboembolism risk in patients with resectable colorectal cancer: A prospective cohort study

Colorectal cancer (CRC), one of the most prevalent types of cancer, is accompanied by a notably high incidence of thrombotic complications. The present study aimed to elucidate the association between KRAS mutations and hypercoagulability in operable CRC. The prognostic value of preoperative D-dimer levels was also investigated, thus providing novel insights into the development of therapeutic strategies to enhance patient survival and diminish morbidity. Therefore, a prospective analysis of 333 CRC cases post-surgery at Yan'an Hospital Affiliated to Kunming Medical University, between May 2019 and October 2022 was performed. Data on demographics, tumor characteristics and D-dimer levels were compiled from the electronic health records. Venous thromboembolism (VTE) was diagnosed by doppler or computed tomography angiography, with D-dimer thresholds set at 550 and 1,650 µg/l. KRAS mutations at codons 12 and 13 were assessed in a subset of 56 cases. Subsequently, the factors affecting the hypercoagulable state in these patients were prospectively analyzed, focusing on the pivotal role of KRAS. The results showed that KRAS mutations were associated with elevated preoperative D-dimer levels, with 1,076 µg/l compared with 485 µg/l in the wild-type cohort, indicative of a hypercoagulable state. Increased D-dimer levels were also associated with vascular invasion, distant metastases and a heightened risk of postoperative VTE. Furthermore, multivariate analyses identified KRAS mutations, distant metastases and vascular invasion as independent predictors of elevated D-dimer levels, with relative risk values of 2.912, 1.884 and 1.525, respectively. Conversely, sex, age, tumor location, differentiation grade, Ki67 index and tumor stage could not significantly affect D-dimer levels, thus indicating a complex interplay between tumor genetics and coagulation dysfunction in CRC. The current study suggested that the KRAS mutation status, distant metastasis and vascular invasion could be considered as independent risk factors of blood hypercoagulability in patients with CRC, potentially serving as prognostic factors for VTE risk.

KRAS-mutant colorectal cancer cell lines cause a prothrombotic state through the upregulation of thrombin: experimental study

Background

The KRAS genotype status is strongly associated with a prothrombotic state in colorectal cancer, and hypercoagulability and cancer-related thrombosis are among the significant events leading to poor prognosis. However, this correlation has not been confirmed at the cellular level. This study aimed to assess the maximum platelet aggregation rate and thrombin expression induced by colorectal cancer cells under different KRAS genotypes.

Materials and methods

Platelet aggregation rate assay and western blotting analysis were used to detect platelet aggregation and thrombin expression induced by four colorectal cancer cells with different KRAS genotypes, including RKO, HCT116, SW480, and SW620. FVIIa/tissue factor and thrombin inhibitors were added to explore changes in platelet aggregation rates induced by colorectal cancer cells and the association between KRAS genotype status and hypercoagulable state.

Results

KRAS-mutant cells were more likely to increase maximal platelet aggregation, with RKO, HCT116, SW480, and SW620 inducing 34.7%, 55.4%, 44.4%, and 63.8% of platelet aggregation, respectively. The maximum platelet aggregation rate was higher in the metastatic rectal cancer tumour strain SW620 than in the primary rectal cancer strain SW480. RKO cells had lower thrombin expression than the other three cells. Furthermore, the addition of thrombin inhibitors caused a more significant decrease in the platelet aggregation rate in KRAS-mutant cell lines compared to KRAS wild-type cell lines.

Conclusion

Compared to KRAS wild-type colorectal cancer cells, KRAS-mutant colorectal cancer cell lines were more likely to be hypercoagulable through the upregulation of thrombin expression, which was mainly achieved through the TF-thrombin pathway.

Therapeutic Potential of Tisotumab Vedotin in the Treatment of Recurrent or Metastatic Cervical Cancer: A Short Report on the Emerging Data

Cervical cancer is the fourth most common type of cancer in women worldwide. It is associated with a high death rate, despite the fact that it is a nearly 100% preventable disease because of very effective primary and secondary preventive strategies. Advanced and recurrent disease is uncurable with a high relapse risk and the second-line therapies are limited with modest response rates and short durability. Investigating alternative mechanisms of action is crucial because of the high request for effective new therapies. Tisotumab vedotin (TV) is the first antibody-drug conjugated to target a cell surface-expressed tissue factor, and preliminary data in patients with metastatic and recurrent cervical cancer have been promising. In addition, the trials showed a favorable tolerability profile, with limited incidence of grade 3 or worse adverse events. According to the data of ENGOT-cx6/GOG-3023/innovaTV 204, the US Food and Drug Administration granted expedited approval of TV on September 20, 2021, for women with recurrent or metastatic cervical cancer. Actually, two other trials testing TV alone or in combination with other agents are ongoing. ENGOT-cx8/GOG-3024/innovaTV 205 is a Phase Ib/II trial of TV in combination with platinum or bevacizumab or pembrolizumab, in patients with recurrent or metastatic cervical cancer who have not received prior systemic therapy or who have progressed after no more than two prior systemic therapies. ENGOT-cx12/GOG-3057/InnovaTV 301 is a Phase 3 trial of TV vs investigator's choice chemotherapy in patients with advanced or recurrent cervical cancer who had received no more than 2 prior chemotherapy lines. The outcomes of these two trials will potentially confirm and reinforce the use of TV as a new standard of care in advanced or recurrent cervical cancer.

Tissue factor (coagulation factor III): a potential double-edge molecule to be targeted and re-targeted toward cancer

Tissue factor (TF) is a protein that plays a critical role in blood clotting, but recent research has also shown its involvement in cancer development and progression. Herein, we provide an overview of the structure of TF and its involvement in signaling pathways that promote cancer cell proliferation and survival, such as the PI3K/AKT and MAPK pathways. TF overexpression is associated with increased tumor aggressiveness and poor prognosis in various cancers. The review also explores TF's role in promoting cancer cell metastasis, angiogenesis, and venous thromboembolism (VTE). Of note, various TF-targeted therapies, including monoclonal antibodies, small molecule inhibitors, and immunotherapies have been developed, and preclinical and clinical studies demonstrating the efficacy of these therapies in various cancer types are now being evaluated. The potential for re-targeting TF toward cancer cells using TF-conjugated nanoparticles, which have shown promising results in preclinical studies is another intriguing approach in the path of cancer treatment. Although there are still many challenges, TF could possibly be a potential molecule to be used for further cancer therapy as some TF-targeted therapies like Seagen and Genmab's tisotumab vedotin have gained FDA approval for treatment of cervical cancer. Overall, based on the overviewed studies, this review article provides an in-depth overview of the crucial role that TF plays in cancer development and progression, and emphasizes the potential of TF-targeted and re-targeted therapies as potential approaches for the treatment of cancer.

A review of the novel tissue factor antibody-drug conjugate: Tisotumab vedotin

OBJECTIVE

To review and compare the pharmacology, efficacy, and safety of the novel tissue factor antibody-drug conjugate, tisotumab vedotin.

DATA SOURCES

Literature search was performed through PubMed MEDLINE, Google Scholar, ClinicalTrials.gov, and the Food and Drug Administration.

DATA SUMMARY

Tisotumab vedotin, a novel tissue factor antibody-drug conjugate, was granted accelerated approval by the US FDA on 20 September 2021 for adult patients with recurrent or metastatic cervical cancer with disease progression on or after chemotherapy. Tisotumab vedotin demonstrated clinical efficacy in a number of solid tumors in innovaTV 201 and more specifically in cervical cancer in the pivotal phase 2 innovaTV 204. In the single-arm innovaTV 204 study, 101 patients with recurrent or metastatic cervical cancer received intravenous tisotumab vedotin at the recommended dose of 2 mg/kg every 3 weeks until disease progression or unacceptable toxicity. The independent review committee confirmed an objective response rate of 24% with 7% complete responses and 17% partial responses. Tisotumab vedotin is associated with several notable adverse events with data from innovaTV 204 including ocular toxicity, hemorrhage, and peripheral neuropathy. Ninety-two percent of patients experienced treatment-related adverse events with 28% experiencing an adverse event of grade 3 or higher.

CONCLUSIONS

Metastatic cervical cancer has a high risk of relapse with few effective second-line therapeutic options. Current guidelines recommend single agent tisotumab vedotin as a possible option. Ongoing trials will further define its place in therapy.

Longitudinal Dynamics of Coagulation and Angiogenesis Markers in Cancer Patients During and After Chemotherapy

Hemostatic parameters have been investigated as molecular determinants of tumor progression. To analyze the dynamics of microparticle-associated tissue factor activity (MPTF), tissue factor antigen (TF-Ag), and angiopоietin-2 (ANG-2) in cancer patients before, during, and after active treatment and to explore their potential as biomarkers for metastatic occurrence and death. Blood for the analysis of MPTF, TF-Ag, ANG-2, and conventional hemostatic tests was sampled in 111 patients with various cancers at 4 consecutive visits: before first chemotherapy cycle, after 3 courses, at the sixth course, and 3 months after chemotherapy cessation. Patients were followed up until metastatic progression/death or the end of the study. MPTF did not change during chemotherapy, but increased significantly after treatment cessation. Total TF-Ag and ANG-2 decreased throughout active treatment. Significant drop of their levels was observed 3 months post therapy cessation. Progressive disease was significantly associated with higher pre-chemotherapy TF-Ag and fibrinogen. Elevated baseline levels of fibrinogen were associated with increased risk of shortened progression free survival. Cessation of chemotherapy is associated with significant change of hemostatic parameters. Pre-chemotherapy levels of TF-Ag and fibrinogen may be informative of disease state and prognosis.

Antibody drug conjugates in gastrointestinal cancer: From lab to clinical development

The antibody-drug conjugates (ADCs) are one the fastest growing biotherapeutics in oncology and are still in their infancy in gastrointestinal (GI) cancer for clinical applications to improve patient survival. The ADC based approach is developed with tumor specific antigen, antibody carrying cytotoxic agents to precisely target and deliver chemotherapeutics at the tumor site. To date, 11 ADCs have been approved by US-FDA, and more than 80 are in the clinical development phase for different oncological indications. However, The ADCs based therapies in GI cancers are still far from having high-efficient clinical outcomes. The limited success of these ADCs and lessons learned from the past are now being used to develop a newer generation of ADC against GI cancers. In this review, we did a comprehensive assessment of the key components of ADCs, including tumor marker, antibody, cytotoxic payload, and linkage strategy, with a focus on technical improvement and some future trends in the pipeline for clinical translation. The various preclinical and clinical ADCs used in gastrointestinal malignancies, their target, composition and bioconjugation, along with preclinical and clinical outcomes, are discussed. The emphasis is also given to new generation ADCs employing novel mAb, payload, linker, and bioconjugation methods are also included.

Current Targets and Bioconjugation Strategies in Photodynamic Diagnosis and Therapy of Cancer

Photodynamic diagnosis (PDD) and therapy (PDT) are emerging, non/minimally invasive techniques for cancer diagnosis and treatment. Both techniques require a photosensitizer and light to visualize or destroy cancer cells. However, a limitation of conventional, non-targeted PDT is poor selectivity, causing side effects. The bioconjugation of a photosensitizer to a tumor-targeting molecule, such as an antibody or a ligand peptide, is a way to improve selectivity. The bioconjugation strategy can generate a tumor-targeting photosensitizer conjugate specific for cancer cells, or ideally, for multiple tumor compartments to improve selectivity and efficacy, such as cancer stem cells and tumor neovasculature within the tumor microenvironment. If successful, such targeted photosensitizer conjugates can also be used for specific visualization and detection of cancer cells and/or tumor angiogenesis (an early event in tumorigenesis) with the hope of an early diagnosis of cancer. The purpose of this review is to summarize some current promising target molecules, e.g., tissue factor (also known as CD142), and the currently used bioconjugation strategies in PDT and PDD, with a focus on newly developed protein photosensitizers. These are genetically engineered photosensitizers, with the possibility of generating a fusion protein photosensitizer by recombinant DNA technology for both PDT and PDD without the need of chemical conjugation. We believe that providing an overview of promising targets and bioconjugation strategies will aid in driving research in this field forward towards more effective, less toxic, and non- or minimally invasive treatment and diagnosis options for cancer patients.

Identification of F5 as a Prognostic Biomarker in Patients with Gastric Cancer

Association of Coagulation factor V (F5) polymorphisms with the occurrence of many types of cancers has been widely reported, but whether it is of prognostic relevance in some cancers remain to be resolved. The RNA-sequencing dataset was downloaded from The Cancer Genome Atlas (TCGA). The potential of F5 genes to predict the survival time of gastric cancer (GC) patients was investigated using univariate and multivariate survival analysis whereas “Kaplan-Meier plotter” (KM-plotter) online tools were employed to validate the outcomes. TCGA data revealed that F5 mRNA levels were significantly upregulated in gastric cancer samples. Survival analysis confirmed that high levels of F5 mRNA correlated with short overall survival (OS) in gastric cancer patients, and the area under the curve (AUC) values of 1-, 2-, and 5-year OS rate were 0.554, 0.593, and 0.603, respectively. Survival analysis by KM-plotter indicated that the high expression of F5 mRNA was significantly associated with a shorter OS compared with the low expression level in all patients with GC, and this was also the case for patients in stage III (hazard ratio (HR) = 1.78, P = 0.017). These findings suggest that the F5 gene is significantly upregulated in GC tumour tissues, and may be a potential prognostic biomarker for GC.

Influence of saliva on the results of global laboratory coagulation tests

BACKGROUND

Oral wounds inevitably come into contact with saliva which can affect the time needed for bleeding to stop. The influence of saliva can be non-specific, related to dilution of blood, and/or mediated by salivary factors that affect haemostasis directly. The aim of this study was to assess if mixing blood with an individual's saliva would affect the rate of its coagulation measured by global coagulation tests, prothrombin time (PT) and activated partial thromboplastin time (APTT).

METHODS

The study included 30 healthy non-smoking volunteers. Paired blood and unstimulated saliva samples were obtained from each participant and PT and APTT were determined in blood, blood + saliva and blood + water mixtures. Coagulation tests were performed using the mechanical clot detection method.

RESULTS

PT was significantly longer in both blood + saliva and blood + water mixtures compared to blood alone. APTT was significantly longer only in blood + water mixture compared to blood.

CONCLUSIONS

Similarly prolonged PT in both mixtures suggests that both saliva and water prolong coagulation evenly due to their non-specific effect of blood dilution. The finding that APTT was significantly prolonged only when blood was mixed with water could indicate presence of tissue factor in saliva, however, in a concentration too low to influence the results of PT.

Activation of TF-Dependent Blood Coagulation Pathway and VEGF-A in Patients with Essential Thrombocythemia

Background and objectives: Recent studies suggest that a vascular endothelial growth factor (VEGF-A) may be involved in the thrombotic process by stimulating the expression of tissue factor in vascular endothelial cells. Tissue factor (TF) can also stimulate the transcription of the gene encoding VEGF-A. The relationship between coagulation and angiogenesis in myeloproliferative neoplasms is not fully understood. The aim of this study was to evaluate the concentration of TF in relation to VEGF-A in the blood of patients with essential thrombocythemia (ET). Patients and methods: The study group consisted of 130, newly diagnosed patients with ET (mean age 61 years). The control group consisted of 35 healthy volunteers (mean age 51 years). Concentrations of VEGF-A, TF, and tissue factor pathway inhibitor (TFPI) were analysed using immunoenzymatic methods. TF and TFPI activities were performed using chromogenic assays. Results: The median concentration of TF Ag was 3-fold higher and the TF activity was more than 15-fold higher in ET patients than in normal individuals. There were no statistically significant differences in the TFPI concentration and activity between groups. VEGF-A was significantly increased in patients with ET (p < 0.000001). Analysis of correlations revealed a positive correlation between VEGF-A and TF Ag as well as a positive correlation between VEGF-A and TFPI activity. Conclusions: The simultaneous increase of TF concentration and activity, VEGF-A in the blood of patients with ET, as well as a positive correlation between the concentration of TF and VEGF-A demonstrates the coexistence of TF-dependent coagulation and activation of angiogenesis.

Early venous thromboembolism at the beginning of palliative chemotherapy is a poor prognostic factor in patients with metastatic pancreatic cancer: a retrospective study

Background

This study investigated the prognostic effects of venous thromboembolism (VTE)-related factors in patients with metastatic pancreatic cancer receiving palliative chemotherapy. Predictive factors for VTE were also investigated.

Methods

A total of 216 patients diagnosed with metastatic pancreatic cancer who received gemcitabine-based palliative chemotherapy at our institution were retrospectively evaluated.

Results

VTE occurred in 51 (23.6%) patients during treatment and did not affect survival. However, patients who were diagnosed with VTE at the beginning of chemotherapy showed poor prognosis compared with patients diagnosed with VTE during chemotherapy: all patients (hazard ratio [HR] 1.897, p = 0.008); patients diagnosed with VTE (HR = 3.768, p = 0.001). Low serum sodium (Na) (< 135 mmol/L) and high Khorana score (≥3) were strong predictive factors of early VTE (odds ratio [OR] 5.109; 95% confidence interval [95% CI] = 1.010–25.845; p = 0.049 for Khorana score, OR 10.304; 95% CI = 1.036–102.466; p = 0.047) for hyponatremia).

Conclusions

Our study demonstrated that occurrence and detection of VTE in the early period of chemotherapy was the most significant VTE-related prognostic factor in patients with metastatic pancreatic cancer receiving chemotherapy. Prediction using the Khorana score and serum Na levels would be helpful in early diagnosis of VTE.

Antibody drug conjugates under investigation in phase I and phase II clinical trials for gastrointestinal cancer

INTRODUCTION

Antibody drug conjugates (ADCs) represent a developing class of anticancer therapeutics which are designed to selectively deliver a cytotoxic payload to tumors, while limiting systemic toxicity to healthy tissues. There are several ADCs which are currently in various stages of clinical development for the treatment of gastrointestinal malignancies.

AREAS COVERED

We discuss the biologic rationale and review the clinical experience with ADCs in the treatment of gastrointestinal malignancies, summarizing the pre-clinical and phase I/II clinical trial data that have been completed or are ongoing.

EXPERT OPINION

While there have been significant advances in the development of ADCs since they were first introduced, several challenges remain. These challenges include (i) the selection of an ideal antigen target which is tumor specific and internalized upon binding, (ii) selection of an antibody which has high affinity for its antigen target and low immunogenicity, (iii) selection of a potent payload which is cytotoxic at sub-nanomolar concentrations, and (iv) optimal design of a linker to confer ADC stability with limited off-site toxicity. Efforts are ongoing to address these issues and innovate the ADC technology to improve the safety and efficacy of these agents.

Activation of carbonic anhydrase IX by alternatively spliced tissue factor under late-stage tumor conditions

Molecules of the coagulation pathway predispose patients to cancer-associated thrombosis and also trigger intracellular signaling pathways that promote cancer progression. The primary transcript of tissue factor, the main physiologic trigger of blood clotting, can undergo alternative splicing yielding a secreted variant, termed asTF (alternatively spliced tissue factor). asTF is not required for normal hemostasis, but its expression levels positively correlate with advanced tumor stages in several cancers, including pancreatic adenocarcinoma. The asTF-overexpressing pancreatic ductal adenocarcinoma cell line Pt45.P1/asTF+ and its parent cell line Pt45.P1 were tested for growth and mobility under normoxic conditions that model early-stage tumors, and in the hypoxic environment of late-stage cancers. asTF overexpression in Pt45.P1 cells conveys increased proliferative ability. According to cell cycle analysis, the major fraction of Pt45.P1/asTF+ cells reside in the dividing G₂/M phase of the cell cycle, whereas the parental Pt45.P1 cells are mostly confined to the quiescent G₀/G₁ phase. asTF overexpression is also associated with significantly higher mobility in cells plated under either normoxia or hypoxia. A hypoxic environment leads to upregulation of carbonic anhydrase IX (CAIX), which is more pronounced in Pt45.P1/asTF+ cells. Inhibition of CAIX by the compound U-104 significantly decreases cell growth and mobility of Pt45.P1/asTF+ cells in hypoxia, but not in normoxia. U-104 also reduces the growth of Pt45.P1/asTF+ orthotopic tumors in nude mice. CAIX is a novel downstream mediator of asTF in pancreatic cancer, particularly under hypoxic conditions that model late-stage tumor microenvironment.

Melanoma-derived IL-1 converts vascular endothelium to a proinflammatory and procoagulatory phenotype via NFκB activation

Spreading of melanoma is associated with efficient extravasation of circulating tumor cells from the vascular system into distant target organs. This process is accompanied and supported by proinflammatory and procoagulatory conditions. In this study, we analysed the ability of human melanoma cell lines to activate endothelial cells (ECs) in vitro. Some melanoma cells, that is, MV3, were shown to trigger an prompt calcium-flux-dependent, procoagulatory endothelial response that was accompanied by luminal release of ultra-large von Willebrand factor (ULVWF) fibres that were immobilized to the endothelial surface layer. In contrast to MV3-derived supernatant, prolonged treatment of ECs with WM9-derived supernatant mediated a pronounced activation of nuclear factor kappa B (NFκB). NFκB activation in ECs was dependent on both IL-1α and IL-1β secreted from melanoma cells. Melanoma-derived IL-1 mediated an upregulation of proinflammatory cytokines IL-6 and IL-8, the intercellular adhesion molecule-1 (ICAM-1), the vascular cell adhesion molecule-1 (VCAM-1) and the procoagulatory tissue factor (TF) in ECs. Our data show that melanoma cells activate ECs either directly and within seconds or by an IL-1-mediated NFκB activation. Both pathways of EC activation convert the regular repressive function of ECs on inflammation and coagulation to a proinflammatory and procoagulatory surface that supports tumor progression.

Tick salivary gland as potential natural source for the discovery of promising antitumor drug candidates

Nowadays, the relationship between cancer blood coagulation is well established. Regarding biodiversity and bioprospection, the tick biology has become quite attractive natural source for coagulation inhibitors, since its saliva has a very rich variety of bioactive molecules. For instance, a Kunitz-type FXa inhibitor, named Amblyomin-X, was found through transcriptome of the salivary gland of the Amblyomma cajennense. tick. This TFPI-like inhibitor, after obtained as recombinant protein, has presented anticoagulant, antigionenic, and antitumor properties. Although its effects on blood coagulation could be relevant for antitumor effect, Amblyomin-X acts by non-hemostatic mechanisms, such as proteasome inhibition and autophagy inhibition. Notably, cytotoxicity was not observed on non-tumor cells treated with this protein, suggesting some selectivity for tumor cells. Considering the current efforts in order to develop effective anticancer therapies, the findings presented in this review strongly suggest Amblyomin-X as a promising novel antitumor drug candidate.

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis

One of the important 'hallmarks' of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.

Suppression of lung cancer cell invasion by LKB1 is due to the downregulation of tissue factor and vascular endothelial growth factor, partly dependent on SP1

LKB1 encodes a serine/threonine kinase generally inactivated in many human cancers, which mediates cancer cell proliferation, migration and differentiation. Recent studies indicated that LKB1 exhibits potent anti-metastatic activity. However, the underlying molecular mechanisms of this activity remain unclear. In this study, we re‑introduced LKB1 into A549 lung cancer cells that lack the LKB1 gene to investigate how LKB1 affects tumor invasiveness and metastasis. We demonstrated that overexpression of the LKB1 protein in lung cancer cells resulted in significant inhibition of invasion. Furthermore, transfected lung cancer cells with LKB1 suppressed tissue factor (TF) and vascular endothelial growth factor (VEGF) expression at both the mRNA and protein levels. Here, we provided evidence showing that downregulation of TF and VEGF by LKB1 is correlated well with the inhibition of cell invasion. Overexpression of the LKB1 protein in human lung cancer is significantly associated with a decrease in activity and expression of the transcription factor SP1. Constitutive activation of the transcription factor Sp1 plays a critical role in TF and VEGF overexpression. We conclude that suppression of lung cancer cell invasion by LKB1 through downregulation of TF and VEGF may partly depend on its inhibitory effect on the transcription factor Sp1. Collectively, our data provide a novel molecular mechanism for the antitumor activity of LKB1 and may help further improve its effectiveness in controlling lung cancer growth and invasion.

Effect of tissue factor knockdown on the growth, invasion, chemoresistance and apoptosis of human gastric cancer cells

This study aimed to explore the role of tissue factor (TF) and evaluate its antitumor effects in the biological processes of gastric cancer cells using the application of RNA interference technology to silence TF in the SGC7901 gastric cancer cell line. Specific small interfering RNA (siRNA) designed for targeting human TF was transfected into SGC7901 cells. The expression levels of TF in the cells were detected by reverse transcription-polymerase chain reaction. Cell proliferation and chemosensitivity were measured by Cell Counting Kit-8. The metastatic potential of the SGC7901 cells was determined by Transwell experiments and wound-healing assays. Cell apoptosis was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide double-staining method. The expression levels of TF mRNA were significantly reduced by the TF-siRNA in the SGC7901 cells, resulting in the suppression of cell proliferation, chemoresistance and invasion, and subsequently the induction of cell apoptosis. TF knockdown with siRNA inhibits the growth, invasion and chemoresistance and enhances the apoptosis of SGC7901 cells, providing a potential approach for gene therapy against human gastric cancer.

Clinical and prognostic significance of coagulation assays in gastric cancer

PURPOSE

Activation of coagulation and fibrinolysis is frequently found among cancer patients. Such tumors are considered to be associated with a higher risk of invasion, metastases, and eventually, worse outcome. The aim of this study is to explore the clinical and prognostic value of blood coagulation tests in gastric cancer (GC) patients.

MATERIALS AND METHODS

A total of 44 consecutive patients with a pathologically confirmed diagnosis of GC were enrolled into the study. Pretreatment blood coagulation tests including prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio (INR), D-dimer (DD), fibrinogen (F) levels, and platelet (PLT) counts were evaluated. Control group comprised 50 age- and sex-matched individuals without history of malignancy and coagulation disorder.

RESULTS

Median age at diagnosis was 55 years, range 19-80 years; most had men (n = 32, 73 %) and metastatic disease (n = 31, 70 %). The level of blood coagulation tests showed a statistically significant difference between the patient and the control groups (P < 0.001 for all, but p = 0.07 for PT). DD levels were significantly associated with elevated PLT and LDH levels (p = 0.009 and p = 0.01, respectively). Patients with metastatic disease had higher levels of F (p = 0.001) and INR (p = 0.027) levels. Elevated DD levels tended to be a poor prognostic factor on outcome (p = 0.06).

CONCLUSION

Change in almost all coagulation tests are found in GC patients and only DD level seems to be of prognostic value.

Venous Thromboembolism in Patients With Myeloma

Myeloma has a well-described association with venous thromboembolism (VTE). There are few dedicated studies investigating the incidence and risk factors. Many assessment scores have been suggested to estimate the risk of VTE in patients with cancer but these have been validated in solid organ tumors. The records of patients with myeloma attending a university hospital between January 2007 and December 2012 were reviewed to investigate the incidence of VTE and the associated risk factors. In all, 217 patients with a mean (standard deviation) age at diagnosis of 65 (12) years were included. Of 217 patients, 12% had an episode of VTE, 69% received at least 1 immunomodulatory agent, and 95% had low or intermediate risk of VTE according to the Khorana score. Venous thromboembolism was a frequent occurrence in this cohort. Patients had many risk factors for VTE but no one was predictive. As myeloma outcomes continue to improve, a dedicated prospective study is warranted to investigate the most appropriate thromboprophylaxis strategy.

Microparticle-associated tissue factor activity in patients with pancreatic cancer: correlation with clinicopathological features

BACKGROUND

Patients with pancreatic cancer have an unfavourable prognosis. A central role in pancreatic cancer progression has been suggested for tissue factor (TF), the main initiator of the blood coagulation cascade. We hypothesized that elevated levels of plasma microparticle (MP)-associated TF activity might indicate the presence of poorly differentiated pancreatic cancer, disease dissemination and infiltration of peripancreatic vessels.

METHODS

MP-TF activity was measured in 73 pancreatic cancer patients and 22 healthy controls. Abdominal computerized tomography (CT) scans performed at study inclusion were investigated for probability of tumoural vascular invasion. In addition, intratumoural TF expression, D-dimer and CA 19-9 levels were determined.

RESULTS

MP-TF activity (pg/mL) was significantly higher in patients (median: 0·37 [range: 0·00-11·91]) than in controls (median: 0·05 [range: 0·00-0·76]; P < 0·001). When pancreatic cancer patients were compared with regard to stage and grade, significantly elevated levels of MP-TF activity were only present in those with poorly differentiated metastatic nonresectable tumours (n = 11, median: 2·95 [range: 0·25-11·91]). In three patients with poorly differentiated tumours, a high probability of vascular invasion was found (MP-TF activity in these cases: 2·95, 7·00 and 10·34). MP-TF activity correlated strongly with CA 19-9 (r = 0·60) and weakly with D-dimer (r = 0·33) levels. Immunohistochemical staining for TF was positive in 14 of 15 resected tumours. MP-TF activity was associated with an increased risk of mortality (HR: 1·8 per doubling in MP-TF activity, [95% CI: 1·4-2·4, P < 0·001]).

CONCLUSION

MP-TF activity might represent a biomarker for a poorly differentiated and invasive pancreatic cancer phenotype and poor survival.

[The cooperation between p53 and Ras in tumorigenesis]

Inactivation of the tumor suppressor gene and activation of the oncogene cooperate to promote the multistep process of tumorigenesis. p53 is considered to be the most important tumor suppressor gene. p53 is usually found as a result of somatic missense mutation in approximately 50% of human cancers. Ras is found to be one of the most frequently mutated oncogenes in human tumors with the reported frequencies ranging from 30% to 90%. It has been found in many studies synergistic effect between tumor suppressor p53 and oncogene Ras occurs during the multistep process of tumorigenesis. According to the current reports, the cooperative effect between p53 and Ras can be divided into three types: the regulation of p53 for Ras function, , the regulation of Ras for p53, and the cooperation between p53 and Ras to control critical genes that are closely related to tumorigenesis. Understanding their synergistic effects will not only help us further disclose mechanism of tumorigenesis caused by p53 inactivation and Ras activation, but also facilitate personalized treatments and pharmacological target selection for cancer therapy. Therefore, we reviewed the recent progress of synergistic effect be-tween p53 and Ras and its role in tumorigenesis.

The tick-derived inhibitor Ixolaris prevents tissue factor signaling on tumor cells

BACKGROUND

Tissue factor (TF) is frequently overexpressed in cancer cells and correlated with more aggressive tumor phenotypes and poor prognosis. In addition to promoting coagulation-dependent metastasis and cancer-associated thrombosis, tumor cell-expressed TF mediates direct cell signaling involving the protease-activated receptor (PAR) 2. Ixolaris is a tick-derived inhibitor of the TF-factor (F)VIIa-Xa coagulation initiation complex which blocks primary tumor growth and angiogenesis in glioblastoma and melanoma models.

METHODS

In this study we address the anti-tumor effects of Ixolaris in TF-VIIa-PAR2 signaling-dependent breast cancer models, a xenograft model of highly aggressive human MDA-MB-231 mfp cells and a syngeneic model of PAR2-deficient and replete PyMT mouse mammary carcinoma cells.

RESULTS

Ixolaris potently inhibited the procoagulant activity of human MDA-MB-231mfp or murine PyMT breast cancer cells. Ixolaris blocked signaling by the ternary TF-FVIIa-FXa complex, and, surprisingly, at higher concentrations also the binary TF-FVIIa complex on MDA-MB-231 cells. We show that Ixolaris interacts with certain residues in the human VIIa protease domain that are involved in PAR2 cleavage. In contrast to human VIIa, Ixolaris was a poor inhibitor of murine TF-FVIIa signaling and did not attenuate PAR2-dependent tumor growth in a syngeneic mouse model of breast cancer progression.

CONCLUSION

These data show that Ixolaris inhibits PAR2 cleavage specifically by human TF signaling complexes and suggest that Ixolaris may block tumor growth of human cell models with ectopic FVIIa expression through inhibition of direct TF-FVIIa-PAR2 signaling as well as its anticoagulant activity.

A randomised controlled pilot trial to evaluate and optimize the use of anti-platelet agents in the perioperative management in patients undergoing general and abdominal surgery--the APAP trial (ISRCTN45810007)

PURPOSE

Surgeons are increasingly confronted by patients on long-term low-dose acetylsalicylic acid (ASA). However, owing to a lack of evidence-based data, a widely accepted consensus on the perioperative management of these patients in the setting of non-cardiac surgery has not yet been reached. Primary objective was to evaluate the safety of continuous versus discontinuous use of ASA in the perioperative period in elective general or abdominal surgery.

METHODS

Fifty-two patients undergoing elective cholecystectomy, inguinal hernia repair or colonic/colorectal surgery were recruited to this pilot study. According to cardiological evaluation, non-high-risk patients who were on long-term treatment with low-dose ASA were eligible for inclusion. Patients were allocated randomly to continuous use of ASA or discontinuation of ASA intake for 5 days before until 5 days after surgery. The primary outcome was the incidence of major haemorrhagic and thromboembolic complications within 30 days after surgery.

RESULTS

A total of 26 patients were allocated to each study group. One patient (3.8%) in the ASA continuation group required re-operation due to post-operative haemorrhage. In neither study group, further bleeding complications occurred. No clinically apparent thromboembolic events were reported in the ASA continuation and the ASA discontinuation group. Furthermore, there were no significant differences between both study groups in the secondary endpoints.

CONCLUSIONS

Perioperative intake of ASA does not seem to influence the incidence of severe bleeding in non-high-risk patients undergoing elective general or abdominal surgery. Further, adequately powered trials are required to confirm the findings of this study.

Tissue factor pathway inhibitor attenuates the progression of malignant pleural mesothelioma in nude mice

Malignant pleural mesothelioma (MPM) is a rare cancer that is refractory to current treatments. It is characterized by a robust deposition of transitional fibrin that is in part promoted by tumor cells. MPM cells express tissue factor (TF) and the tissue factor pathway inhibitor (TFPI), but their contribution to the pathogenesis of MPM has been unclear. We found that REN MPM cells fail to express TFPI. Based on the tumor growth-promoting properties of TF, we hypothesized that the stable transfection of TFPI into REN MPM cells would decrease their aggressiveness. We tested our hypothesis using in vitro, in vivo, and ex vivo analyses. TFPI knock-in decreased the proliferation, invasion, and TF activity of REN cells in vitro. REN TFPI knock-in cells, empty vector, and naive control cells were next injected intrapleurally into nude mice. The expression of TFPI significantly decreased tissue invasion, inflammation, and the deposition of fibrin and collagen associated with tumor tissue, pleural effusions, and tumor burden. In ex vivo analyses, REN cells were cultured from harvested tumors. The overexpression of TFPI was maintained in cells propagated from TFPI knock-in tumors, and attenuated the activation of Factor X and the invasiveness of tumor cells. These analyses demonstrate that TFPI reduces the aggressiveness of MPM in vitro and in vivo, and that its effect involves the inhibition of TF procoagulant activity. These observations suggest that the interactions of TF and TFPI represent a novel therapeutic target in the treatment of MPM.

Small interference RNA targeting tissue factor inhibits human lung adenocarcinoma growth in vitro and in vivo

Background

The human coagulation trigger tissue factor (TF) is overexpressed in several types of cancer and involved in tumor growth, vascularization, and metastasis. To explore the role of TF in biological processes of lung adenocarcinoma, we used RNA interference (RNAi) technology to silence TF in a lung adenocarcinoma cell line A549 with high-level expression of TF and evaluate its antitumor effects in vitro and in vivo.

Methods

The specific small interfering RNA (siRNA) designed for targeting human TF was transfected into A549 cells. The expression of TF was detected by reverse transcription-PCR and Western blot. Cell proliferation was measured by MTT and clonogenic assays. Cell apoptosis was assessed by flow cytometry. The metastatic potential of A549 cells was determined by wound healing, the mobility and Matrigel invasion assays. Expressions of PI3K/Akt, Erk1/2, VEGF and MMP-2/-9 in transfected cells were detected by Western blot. In vivo, the effect of TF-siRNA on the growth of A549 lung adenocarcinoma xenografts in nude mice was investigated.

Results

TF -siRNA significantly reduced the expression of TF in the mRNA and protein levels. The down-regulation of TF in A549 cells resulted in the suppression of cell proliferation, invasion and metastasis and induced cell apoptosis in dose-dependent manner. Erk MAPK, PI3K/Akt pathways as well as VEGF and MMP-2/-9 expressions were inhibited in TF-siRNA transfected cells. Moreover, intratumoral injection of siRNA targeting TF suppressed the tumor growth of A549 cells in vivo model of lung adenocarcinoma.

Conclusions

Down-regulation of TF using siRNA could provide a potential approach for gene therapy against lung adenocarcinoma, and the antitumor effects may be associated with inhibition of Erk MAPK, PI3K/Akt pathways.

Association study of selected genetic polymorphisms and occurrence of venous thromboembolism in patients with multiple myeloma who were treated with thalidomide

INTRODUCTION/BACKGROUND

Venous thromboembolism (VTE), with the subsequent risk of pulmonary embolism, is a common adverse effect of thalidomide treatment in patients with multiple myeloma (MM). In our retrospective study, we analyzed candidate single-nucleotide polymorphisms (SNP), CINP (rs7011), CETP (rs289747), ALDH1A1 (rs610529), CDKN1A (rs3829963), GAN (rs2608555), vascular endothelial growth factor (rs699947), and ALDH1A1 (rs168351), previously identified in a large association study based on the hypothesis-driven candidate gene approach nominated by the International Myeloma Foundation "Bank On A Cure" (3404 SNPs). In that study, the researchers built a classification tree that enables prediction of individual risk of VTE in patients with MM.

PATIENTS AND METHODS

Genotypes of these SNPs were determined in an independent cohort of 111 patients with MM through TaqMan real-time polymerase chain reaction (PCR) allelic discrimination and were used for prediction of individual VTE risk.

RESULTS

The results of this study did not confirm the ability of this classification tree to predict VTE risk in patients with MM from the Czech Republic; of these patients, 21 (19%) developed high-grade VTE. However, in patients with VTE, we found higher frequency of the AC genotype in the CDKN1A gene (42.9% vs. 16.7%; odds ratio 3.64) in comparison with the CC genotype (P = .015). SNPs of other genes as well as age and sex of the patients had no statistically significant influence on the risk of VTE.

CONCLUSION

Further studies are needed to confirm the initial analysis that provided predictive information of genetic variations in patients with myeloma that may influence risk of VTE.

The mechanism of melanoma-associated thrombin activity and von Willebrand factor release from endothelial cells

Activation of the coagulation system in malignancy enables tumor spreading and is thus associated with poor prognosis for the patient. In this study, we analyzed the in vitro mechanisms by which two human metastatic melanoma cell lines, MV3 and WM9, transform the vascular endothelium into a prothrombotic activated state. We show that both melanoma cell lines activate prothrombin due to tissue factor (TF) expression by showing that thrombin generation was blocked with a TF-neutralizing antibody and TF-siRNA. In addition, using the cysteine protease inhibitor E-64, we excluded the formerly described cancer procoagulant (CP) as a major factor contributing to thrombin generation. Furthermore, we describe a direct thrombin-independent response of endothelial cells (ECs) to MV3-derived supernatant as measured by rapid release of VWF. We also show that two clinically approved LMWHs, tinzaparin and enoxaparin, are effective inhibitors of thrombin generation and thrombin activity in plasma. Furthermore, our data indicate a protective effect of heparins on EC activation as shown by reduced VWF release in response to MV3 supernatant. These promising effects of heparins on the melanoma-induced thrombotic conditions justify further clinical investigations in the field of oncology.

Tissue factor: beyond coagulation in the cardiovascular system

TF (tissue factor) is the main trigger of the coagulation cascade; by binding Factor VIIa it activates Factor IX and Factor X, thereby resulting in fibrin formation. Various stimuli, such as cytokines, growth factors and biogenic amines, induce TF expression and activity in vascular cells. Downstream targets of these mediators include diverse signalling molecules such as MAPKs (mitogen-activated protein kinases), PI3K (phosphoinositide 3-kinase) and PKC (protein kinase C). In addition, TF can be detected in the bloodstream, known as circulating or blood-borne TF. Many cardiovascular risk factors, such as hypertension, diabetes, dyslipidaemia and smoking, are associated with increased expression of TF. Furthermore, in patients presenting with acute coronary syndromes, elevated levels of circulating TF are found. Apart from its role in thrombosis, TF has pro-atherogenic properties, as it is involved in neointima formation by inducing vascular smooth muscle cell migration. As inhibition of TF action appears to be an attractive target for the treatment of cardiovascular disease, therapeutic strategies are under investigation to specifically interfere with the action of TF or, alternatively, promote the effects of TFPI (TF pathway inhibitor).

rNAPc2 inhibits colorectal cancer in mice through tissue factor

PURPOSE

Recombinant nematode anticoagulant protein c2 (rNAPc2) is a specific inhibitor of tissue factor (TF)/factor VIIa complex with novel antithrombotic activity. TF is highly expressed in human colorectal tumors, and levels are positively correlated with disease progression.

EXPERIMENTAL DESIGN

To explore the therapeutic potential and mechanism of action of rNAPc2 during tumor growth and metastasis, we tested rNAPc2 in several experimental colorectal cancer models in mice.

RESULTS

Administration of rNAPc2 inhibited pulmonary metastasis in mice systemically disseminated with CT26 murine colon carcinoma cells in a dose-dependent fashion. Combining rNAPc2 with the cytotoxic agent 5-fluorouracil or bevacizumab (humanized anti-vascular endothelial growth factor monoclonal antibody) resulted in additive growth inhibition and simultaneous reduction of microvessel density in HCT116 human colorectal tumor xenografts in nude mice. Furthermore, rNAPc2 potentiated CPT-11 in inhibiting hepatic metastasis in nude mice with portal vein injection of HCT116 tumor cells. Long-term administration of rNAPc2 significantly suppressed spontaneous formation of intestinal tumors in Apc(Min/+) mice. Using a RNA interference approach, we showed that TF expression is necessary for rNAPc2-mediated inhibition of HCT116 human colorectal tumor xenograft growth in nude mice, indicating that the antitumor effect of rNAPc2 may be transduced through TF that is expressed on tumor cells.

CONCLUSIONS

rNAPc2 is a potent anticancer agent when used in combination with chemotherapy or antiangiogenic therapy in mouse models of colorectal cancer, and TF positivity appears to be required for its activity.

Regulation of gene expression by estrogen in mammary gland of wild type and estrogen receptor alpha knockout mice

Using serial analysis of gene expression, we examined the effects of estrogen (E2) replacement in gonadectomized wild type (WT) and E2 receptor alpha knockout (ERalphaKO) mice on global gene expression in mammary gland. In WT mice, a total of 429,302 tags were sequenced, representing the expression level of 99,854 tag species. A total of ten transcripts were found to be modulated by E2, such as sorting nexin 5 and two no match tags. In the ERalphaKO mice, a total of 459,439 tags were sequenced, representing the expression level of 120,149 tag species. Interestingly, the same three transcripts were inversely regulated by E2 in ERalphaKO mice. In total, 78 transcripts were upregulated by E2, while 29 transcripts were downregulated. In contrast to WT mice, the majority of transcripts related to immunity were repressed in ERalphaKO mice. Moreover, induction of transcripts involved in cell differentiation, Ca2+ response, cytoskeleton, protein biosynthesis and secretion, glycolysis, and oxidative phosphorylation were seen only in ERalphaKO mice. The current study will provide useful information to understand the cellular mechanisms of E(2)-mediated gene regulation in tissues in vivo for the development of novel drugs targeting specific ER action in pathological conditions.

Fibrinogen-like protein 2/fibroleukin prothrombinase contributes to tumor hypercoagulability via IL-2 and IFN-γ

AIM: To examine the role of Fibrinogen-like protein 2 (fgl2)/fibroleukin in tumor development. Fgl2 has been reported to play a vital role in the pathogenesis in MHV-3 (mouse hepatitis virus) induced fulminant and severe hepatitis, spontaneous abortion, allo- and xeno- graft rejection by mediating “immune coagulation”.

METHODS: Tumor tissues from 133 patients with six types of distinct cancers and the animal tumor tissues from human hepatocellular carcinoma (HCC) model on nude mice (established from high metastasis HCC cell line MHCC97LM6) were obtained.

RESULTS: Hfgl2 was detected in tumor tissues from 127 out of 133 patients as well as tumor tissues collected from human HCC nude mice. Hfgl2 was highly expressed both in cancer cells and interstitial inflammatory cells including macrophages, NK cells, and CD8⁺ T lymphocytes and vascular endothelial cells. Hfgl2 mRNA was localized in cells that expressed hfgl2 protein. Fibrin (nogen) co-localization with hfgl2 expression was determined by dual immunohistochemical staining. In vitro, IL-2 and IFN-γ increased hfgl2 mRNA by 10-100 folds and protein expression in both THP-1 and HUVEC cell lines. One-stage clotting assays demonstrated that THP-1 and HUVEC cells expressing hfgl2 had increased procoagulant activity following cytokines stimulation.

CONCLUSION: The hfg12 contributes to the hypercoagulability in cancer and may induce tumor angiogenesis and metastasis via cytokine induction.

Genetic associations with thalidomide mediated venous thrombotic events in myeloma identified using targeted genotyping

A venous thromboembolism (VTE) with the subsequent risk of pulmonary embolism is a major concern in the treatment of patients with multiple myeloma with thalidomide. The susceptibility to developing a VTE in response to thalidomide therapy is likely to be influenced by both genetic and environmental factors. To test genetic variation associated with treatment related VTE in patient peripheral blood DNA, we used a custom-built molecular inversion probe (MIP)-based single nucleotide polymorphism (SNP) chip containing 3404 SNPs. SNPs on the chip were selected in "functional regions" within 964 genes spanning 67 molecular pathways thought to be involved in the pathogenesis, treatment response, and side effects associated with myeloma therapy. Patients and controls were taken from 3 large clinical trials: Medical Research Council (MRC) Myeloma IX, Hovon-50, and Eastern Cooperative Oncology Group (ECOG) EA100, which compared conventional treatments with thalidomide in patients with myeloma. Our analysis showed that the set of SNPs associated with thalidomide-related VTE were enriched in genes and pathways important in drug transport/metabolism, DNA repair, and cytokine balance. The effects of the SNPs associated with thalidomide-related VTE may be functional at the level of the tumor cell, the tumor-related microenvironment, and the endothelium. The clinical trials described in this paper have been registered as follows: MRC Myeloma IX: ISRCTN68454111; Hovon-50: NCT00028886; and ECOG EA100: NCT00033332.

Alternatively spliced human tissue factor promotes tumor growth and angiogenesis in a pancreatic cancer tumor model

INTRODUCTION

Tissue Factor (TF) expression is observed in many types of cancer, associated with more aggressive disease, and thrombosis. Alternatively-spliced human tissue factor (asHTF) has recently been identified in which exon 5 is deleted. asHTF is soluble due to the substitution of the transmembrane and cytoplasmic domains of exon 6 with a unique COOH-terminal domain.

MATERIALS AND METHODS

We examine the expression and function of asHTF and full-length Tissue Factor ((FL)TF) in six human pancreatic cancer cells. Further, we transfected asHTF, (FL)TF, and control expression vectors into a non-expressing, human pancreatic cancer line (MiaPaCa-2). We studied the procoagulant activity of asHTF and (FL)TF and the effect on tumor growth in mice.

RESULTS

asHTF is expressed in 5 of 6 human pancreatic cancer cell lines, but not in normal human fibroblasts, nor the MiaPaCa-2 line. (FL)TF conferred procoagulant activity, but asHTF did not. Transfected cells were injected subcutaneously in athymic mice. Interestingly, compared with control transfection, (FL)TF expression was associated with reduced tumor growth (mean 7 mg vs 85 mg), while asHTF-expression was associated with enhanced tumor growth (mean 389 mg vs. 85 mg). asHTF expression resulted in increased mitotic index and microvascular density.

CONCLUSIONS

These data suggests that asHTF expression promotes tumor growth, and is associated with increased tumor cell proliferation and angiogenesis in vivo. Our results raise a new perspective on the understanding of the relationship between TF expression and cancer growth, by showing a dissociation of the procoagulant activity of (FL)TF and the cancer-promoting activity of asHTF.