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

Epidemiology of breast cancer, a paradigm of the "common soil" hypothesis

Breast cancer is the leading cause of death in women aged 20-50 years, with some geographical difference. The yearly incidence of the disease is increasing while the related mortality is steadily decreasing. Breast cancer is associated not only with specific hormones or factors related with reproduction, but mostly to more general environmental factors, linked to socioeconomic conditions and lifestyles (smoking, stress, physical exercise and particularly dietary habits). The latter, indeed, are risk factors or conditions common to hormone-dependent tumors and other chronic degenerative disorders, such as ischemic cardio cerebro-vascular and neuro-degenerative disease. Breast cancer can indeed be considered as a paradigm of the so-called "common soil" concept, according to which the above mentioned conditions, although having different clinical manifestations, share some pathogenetic mechanisms and risk factors and intermediate predisposing phenotypes (see Type2 diabetes, metabolic syndrome or obesity). In an epidemiological perspective, evidence has been accumulated on the common response of breast cancer and cardiovascular disorders to healthy lifestyles and in particular to the beneficial effects of a close adhesion to the Mediterranean dietary model. The latter would mainly be effective thanks to its anti-inflammatory properties, thus controlling the subclinical condition of low-grade inflammation, a common risk factor of all the "common soil" disorders. Results from the prospective cohort of the Moli-sani Study (nearly 25,000 adults from the general population of the Southern Italy region of Molise) are highly suggestive in this context. In a public health perspective, the "common soil" hypothesis may thus promote the application of preventive strategies, particularly targeting lifestyles, for a broad spectrum of widely prevalent disorders, ranging from breast cancer to myocardial infarction or cognitive impairment conditions.

In Vitro Assessment of Nanoparticle Effects on Blood Coagulation

Blood clotting is a complex process which involves both cellular and biochemical components. The key cellular players in the blood clotting process are thrombocytes or platelets. Other cells, including leukocytes and endothelial cells, contribute to clotting by expressing the so-called pro-coagulant activity (PCA) complex on their surface. The biochemical component of blood clotting is represented by the plasma coagulation cascade, which includes plasma proteins also known as coagulation factors. The coordinated interaction between platelets, leukocytes, endothelial cells, and plasma coagulation factors is necessary for maintaining hemostasis and for preventing excessive bleeding. Undesirable activation of all or some of these components may lead to pathological blood coagulation and life-threatening conditions such as consumptive coagulopathy or disseminated intravascular coagulation (DIC). In contrast, unintended inhibition of the coagulation pathways may lead to hemorrhage. Thrombogenicity is the property of a test material to induce blood coagulation by affecting one or more elements of the clotting process. Anticoagulant activity refers to the property of a test material to inhibit coagulation. The tendency to cause platelet aggregation, perturb plasma coagulation, and induce leukocyte PCA can serve as an in vitro measure of a nanomaterial's likelihood to be pro- or anticoagulant in vivo. This chapter describes three procedures for in vitro analyses of platelet aggregation, plasma coagulation time, and activation of leukocyte PCA. Platelet aggregation and plasma coagulation procedures have been described earlier. The revision here includes updated details about nanoparticle sample preparation, selection of nanoparticle concentration for the in vitro study, and updated details about assay controls. The chapter is expanded to describe a method for the leukocyte PCA analysis and case studies demonstrating the performance of these in vitro assays.

Lung cancer chemotherapy agents increase procoagulant activity via protein disulfide isomerase-dependent tissue factor decryption

Lung cancer patients undergoing chemotherapy have an elevated risk for thrombosis. However, the mechanisms by which chemotherapy agents increase the risk for thrombosis remains unclear. The aim of this study was to determine the mechanism(s) by which lung cancer chemotherapy agents cisplatin, carboplatin, gemcitabine, and paclitaxel elicit increased tissue factor activity on endothelial cells, A549 cells, and monocytes. Tissue factor activity, tissue factor antigen, and phosphatidylserine exposure were measured on chemotherapy-treated human umbilical vein endothelial cells (HUVEC), A549 cells, and monocytes. Cell surface protein disulfide isomerase (PDI) and cell surface free thiol levels were measured on HUVEC and A549 non-small cell lung carcinoma cells. Treatment of HUVECs, A549 cells, and monocytes with lung cancer chemotherapy significantly increased cell surface tissue factor activity. However, elevated tissue factor antigen levels were observed only on cisplatin-treated and gemcitabine-treated monocytes. Cell surface levels of phosphatidylserine were increased on HUVEC and monocytes treated with cisplatin/gemcitabine combination therapy. Chemotherapy also resulted in increased cell surface levels of PDI and reduced cell surface free thiol levels. Glutathione treatment and PDI inhibition, but not phosphatidylserine inhibition, attenuated tissue factor activity. Furthermore, increased tissue factor activity was reversed by reducing cysteines with dithiothreitol. These studies are the first to demonstrate that lung cancer chemotherapy agents increase procoagulant activity on endothelial cells and A549 cells by tissue factor decryption through a disulfide bond formation in a PDI-dependent mechanism.

Plant natural products: from traditional compounds to new emerging drugs in cancer therapy

Natural products are chemical compounds or substances produced naturally by living organisms. With the development of modern technology, more and more plant extracts have been found to be useful to medical practice. Both micromolecules and macromolecules have been reported to have the ability to inhibit tumour progression, a novel weapon to fight cancer by targeting its 10 characteristic hallmarks. In this review, we focus on summarizing plant natural compounds and their derivatives with anti-tumour properties, into categories, according to their potential therapeutic strategies against different types of human cancer. Taken together, we present a well-grounded review of these properties, hoping to shed new light on discovery of novel anti-tumour therapeutic drugs from known plant natural sources.

The pharmacological bases of the antiangiogenic activity of paclitaxel

In the mid 1990s, researchers began to investigate the antiangiogenic activity of paclitaxel as a possible additional mechanism contributing to its antineoplastic activity in vivo. In the last decade, a number of studies showed that paclitaxel has antiangiogenic activity that could be ascribed to the inhibition of either tubule formation or cell migration, and to an antiproliferative effect towards activated endothelial cells. Furthermore, paclitaxel was shown to downregulate VEGF and Ang-1 expression in tumor cells, and to increase the secretion of TSP-1 in the tumor microenvironment. Moreover, the new pharmaceutical formulations of paclitaxel (such as liposome-encapsulated paclitaxel, ABI-007, and paclitaxel entrapped in emulsifying wax nanoparticles) enhanced the in vivo antiangiogenic activity of the drug. Thus, the preclinical data of paclitaxel may be exploited to implement a novel and rational therapeutic strategy to control tumor progression in patients.

Breast cancer as an acquired thrombophilic state

Cancer is an acquired thrombophilic condition manifested by increased incidence of venous and arterial thromboembolic complications. Despite progress that has been achieved in treatments over the recent years, thromboembolism remains a major complication in patients with breast cancer; it is accompanied by significant morbidity and mortality. Approximately, 1% of breast cancer patients develop venous thromboembolism within 2 years with the highest incidence occurring in the 6 months post diagnosis. Metastatic disease and their comorbidities are the strongest predictors of the development of thrombotic event. The diagnosis of venous thromboembolism is associated with a higher risk of death within 2 years of diagnosis. Thromboembolic events in cancer patients range from abnormal laboratory coagulation tests without specific symptoms to massive thomboembolism and disseminated intravascular coagulation. The underlying pathophysiology is complex and includes the prothrombotic properties of cancer cells, which can be enhanced by anticancer treatment modalities, such as surgery, hormonal agents, and chemotherapy. Primary thromboprophylaxis in cancer patients should be individualized according to risk. For secondary prevention, several clinical studies have shown that low molecular weight heparin has improved patients' compliance, cancer outcomes and overall survival. This review summarizes the available data on the pathogenesis and clinical approach of hemostatic changes in breast cancer.

Dendrimer-induced leukocyte procoagulant activity depends on particle size and surface charge

Aims: Thrombogenicity associated with the induction of leukocyte procoagulant activity (PCA) is a common complication in sepsis and cancer. Since nanoparticles are increasingly used for drug delivery, their interaction with coagulation systems is an important part of the safety assessment. The purpose of this study was to investigate the effects of nanoparticle physicochemical properties on leukocyte PCA, and to get insight into the mechanism of PCA induction. Materials & Methods: A total of 12 formulations of polyamidoamine (PAMAM) dendrimers, varying in size and surface charge, were studied in vitro using recalcification time assay. Results: Irrespective of their size, anionic and neutral dendrimers did not induce leukocyte PCA in vitro. Cationic particles induced PCA in a size- and charge-dependent manner. The mechanism of PCA induction was similar to that of doxorubicin. Cationic dendrimers were also found to exacerbate endotoxin-induced PCA. Conclusion: PAMAM dendrimer-induced leukocyte PCA depends on particle size, charge and density of surface groups.

Inhibition of the renin-angiotensin system downregulates tissue factor and vascular endothelial growth factor in human breast carcinoma cells

INTRODUCTION

The renin-angiotensin system (RAS) promotes angiogenesis and growth of neoplastic cells. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor AT1 blockers may protect against cancer. Tissue factor (TF), for its involvement in tumor growth, angiogenesis, and metastasis is considered a hallmark of cancer progression. In this study we evaluated whether RAS blockade modulates TF constitutive expression by the metastatic breast carcinoma MDA-MB-231 cell line.

MATERIALS AND METHODS

Cell TF activity was assessed by one stage clotting time, TF and VEGF antigens and mRNA levels by ELISA and RT-PCR, respectively. AT(1) was detected by flow-cytometry and angiotensin-II levels by EIA.

RESULTS

Captopril reduced in a concentration-dependent way both the strong constitutive TF activity (983.2±55.2 vs. 686.7±135.1U/5×10(5) cells with 10μg/ml captopril) and antigen (32.3±5.9 vs. 13.2±6.6ng/ml) in MDA-MB-231. Similar results were observed with enalapril. AT1 was present on cell membrane and losartan, a competitive inhibitor of AT1, reduced TF expression to a degree similar as that exerted by ACE inhibitors. Moreover, captopril and losartan downregulated the constitutive mRNA TF expression by ~35%. Similar results were observed with anti-AT1 and angiotensin II antibodies. In addition, the constitutive VEGF antigen and mRNA levels were reduced in the presence of captopril or losartan, and an anti-VEGF antibody downregulated cell TF activity by ~40%.

CONCLUSIONS

These results could, at least in part, contribute to the discussion about the possible effects of ACE inhibitors and AT1 receptor antagonists in malignancy, and offer new clues to support their use for tumor control.

Tissue factor, blood coagulation, and beyond: an overview

Emerging evidence shows a broad spectrum of biological functions of tissue factor (TF). TF classical role in initiating the extrinsic blood coagulation and its direct thrombotic action in close relation to cardiovascular risks have long been established. TF overexpression/hypercoagulability often observed in many clinical conditions certainly expands its role in proinflammation, diabetes, obesity, cardiovascular diseases, angiogenesis, tumor metastasis, wound repairs, embryonic development, cell adhesion/migration, innate immunity, infection, pregnancy loss, and many others. This paper broadly covers seminal observations to discuss TF pathogenic roles in relation to diverse disease development or manifestation. Biochemically, extracellular TF signaling interfaced through protease-activated receptors (PARs) elicits cellular activation and inflammatory responses. TF diverse biological roles are associated with either coagulation-dependent or noncoagulation-mediated actions. Apparently, TF hypercoagulability refuels a coagulation-inflammation-thrombosis circuit in “autocrine” or “paracrine” fashions, which triggers a wide spectrum of pathophysiology. Accordingly, TF suppression, anticoagulation, PAR blockade, or general anti-inflammation offers an array of therapeutical benefits for easing diverse pathological conditions.

Signal transducer and activator of transcription 3 pathway mediates genipin-induced apoptosis in U266 multiple myeloma cells

It has drawn a lot of attention to target signal transducer and activator of transcription 3 (STAT3) as a potential strategy for cancer therapeutics. Using several myelogenous cell lines, the effect of genipin (an active compound of Gardenia fruit) on the STAT3 pathway and apoptosis was investigated. Genipin suppressed the constitutive STAT3 activation in U266 and U937 cells and stimulated Src homology 2 domain-containing phosphatase 1 (SHP-1), which dephosphorylates and inactivates STAT3. Specifically, genipin blocked STAT3 activation via repressing the activation of c-Src, but not Janus kinase 1 (JAK1). Genipin also downregulated the expression of STAT3 target genes including Bcl-2, Bcl-x(L) , Survivin, Cyclin D1, and VEGF. Conversely, protein tyrosine phosphatase inhibitor pervanadate blocked genipin induced STAT3 inactivation. Using DNA fragmentation or TUNEL assays, we demonstrated the apoptotic effect of genipin on U266, MM.1S, and U937 cells. Furthermore, genipin effectively potentiated the cytotoxic effect of chemotherapeutic agents, such as bortezomib, thalidomide, and paclitaxel in U266 cells. Our data suggest that through regulation of Src and SHP-1, genipin antagonizes STAT3 for the induction of apoptosis in myeloma cells.

Paclitaxel potentiates inflammatory cytokine-induced prothrombotic molecules in endothelial cells

To overcome the limitations of balloon expandible metal stent-induced neointimal smooth muscle cell proliferation, drug-coated stent devices have been developed. Drug eluting stents release high concentrations of antiproliferative agents, such as paclitaxel, to reduce neointimal hyperplasia. The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), is known to cause severe endothelial dysfunction and accelerate atherosclerotic lesion progression. The interaction of TNF-alpha and paclitaxel on the release of prothrombotic molecules was examined in endothelial cells. Treatment of endothelial cells with paclitaxel had no direct effect on tissue factor (TF) expression, but TNF-alpha increased TF. Cotreatment of paclitaxel with TNF-alpha markedly augmented the release of TF. TNF-alpha induced release of plasminogen activator inhibitor but no synergism occurred with paclitaxel. Treatment of endothelial cells with paclitaxel and TNF-alpha reduced expression of thrombomodulin and protein C receptor. Tissue factor pathway inhibitor expression was reduced by prolonged treatment with either paclitaxel or TNF-alpha. The adhesion molecule, CD62 E, was induced by TNF-alpha; however, CD31, CD62 P, and CD106 were not affected by paclitaxel and TNF-alpha. Apoptosis was not observed with cotreatment of endothelial cells with paclitaxel and TNF-alpha. CD59-positive microparticles were released in response to TNF-alpha, but the release was not augmented by paclitaxel. Paclitaxel and TNF-alpha increased the nitrotyrosination of proteins. These findings indicate that paclitaxel enhances TNF-alpha-induced release of TF, and downregulated thrombomodulin, increased protein nitration, which may subsequently favor prothrombotic intimal surface.