Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants ...can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named "brachialactone," this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a γ-lactone ring. It contributed 60-90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in NITROSOMONAS: Release of this inhibitor is a regulated plant function, triggered and sustained by the availability of ammonium (NHFormula: see text) in the root environment. Brachialactone release is restricted to those roots that are directly exposed to NHFormula: see text. Within 3 years of establishment, Brachiaria pastures have suppressed soil nitrifier populations (determined as amoA genes; ammonia-oxidizing bacteria and ammonia-oxidizing archaea), along with nitrification and nitrous oxide emissions. These findings provide direct evidence for the existence and active regulation of a nitrification inhibitor (or inhibitors) release from tropical pasture root systems. Exploiting the BNI function could become a powerful strategy toward the development of low-nitrifying agronomic systems, benefiting both agriculture and the environment.
Cancer patients are at increased risk of developing thrombosis, comorbidity that has been associated with increased neutrophil counts and the formation of neutrophil extracellular traps (NETs). ...Interleukin-1β (IL-1β) modulates the expression of granulocyte colony-stimulating factor (G-CSF), a cytokine that promotes cancer-associated neutrophilia and NET generation. Herein, we combined a murine breast cancer model with a flow-restriction thrombosis model to evaluate whether the IL-1β blockade could interfere with cancer-associated thrombosis. Mice bearing metastatic 4T1 tumors exhibited high neutrophil counts as well as elevated expression of G-CSF and IL-1β in their tumors. On the other hand, mice bearing non-metastatic 67NR tumors showed no elevation in neutrophil counts and displayed low expression levels of G-CSF and IL-1β in their tumors. 4T1 tumor-bearing mice but not 67NR tumor-bearing mice exhibited a NET-dependent prothrombotic state. Pharmacological blockade of IL-1 receptor (IL-1R) decreased the primary growth of 4T1 tumors and reduced the systemic levels of myeloperoxidase, cell-free DNA (cfDNA) and G-CSF, without interfering with the neutrophil counts. Most remarkably, the blockade of IL-1R abolished the prothrombotic state observed in 4T1 tumor-bearing mice. Overall, our results demonstrate that IL-1β might be a feasible target to attenuate cancer-associated thrombosis, particularly in cancer types that rely on increased G-CSF production and involvement of NET formation.
Background
Radiofrequency ablation of malignant biliary strictures has been offered for the last 3 years, but only limited data have been published.
Aim
To assess the safety, efficacy, and survival ...outcomes of patients receiving endoscopic radiofrequency ablation.
Methods
Between April 2010 and December 2013, 69 patients with unresectable neoplastic lesions and malignant biliary obstruction underwent 98 radiofrequency ablation sessions with stenting.
Results
A total of 69 patients (22 male, aged 66.1 ± 13.3) were included in the registry. The etiology of malignant biliary stricture included unresectable cholangiocarcinoma (
n
= 45), pancreatic cancer (
n
= 19), gallbladder cancer (
n
= 2), gastric cancer (
n
= 1), and liver metastasis from colon cancer (
n
= 3). Seventy-eight percentage of patients had prior chemotherapy. All strictures were stented post-radiofrequency ablation with either plastic stents or metal stents. The mean stricture length treated was 14.3 mm. There was a statistically significant improvement in stricture diameter post-ablation (
p
< 0.0001). The likelihood of stricture improvement was significantly greater in pancreatic cancer-associated strictures RR 1.8 (95 % 1.03–5.38). Seven patients (10 %) had adverse events, not linked directly to radiofrequency ablation. Median survival was 11.46 months (6.2–25 months).
Conclusion
Radiofrequency ablation is effective and safe in malignant biliary obstruction and seems to be associated with improved survival.
Extracellular vesicles, such as microvesicles (MVs), were identified as important players in tumor progression and acquisition of an aggressive phenotype. Tissue factor (TF) is a transmembrane ...protein that initiates the blood coagulation cascade. In tumor cells, TF has been associated with aggressiveness and cancer progression. Previous studies demonstrate that TF is incorporated into MVs secreted by tumor cells; however, it is unknown whether TF is actively involved in the release of MVs. Here, we investigated the influence of TF expression on the release of MVs. TF silencing was achieved through CRISPR/Cas9 approaches in the human breast cancer cell line, MDA-MB-231. TF knockout in MDA-MB-231 cells efficiently reduced TF-dependent signaling and procoagulant activity. Remarkably, silencing of TF caused a significant decrease in the number of MVs released by MDA-MB-231 cells. We also observed an increase in actin-positive membrane projections in TF knockout cells and a reduction in RhoA expression when compared to TF-expressing cells. Treatment of MDA-MB-231 cells with the RhoA-ROCK signaling pathway inhibitor, fasudil, significantly reduced the release of MVs. Taken together, our results suggest a novel and relevant role for TF in tumor biology by playing an active role in the MVs secretion.
•TF knockout in MDA-MB-231 cells reduced TF/FVIIa signaling and coagulation activity.•Silencing of TF in MDA-MB-231 cells decreased the release of MVs.•RhoA expression is decreased in TF-silenced MDA-MB-231 cells.•The ROCK inhibitor, fasudil, decreases MVs shedding by MDA-MB-231 cells.
Tissue Factor (TF) is the initiator of blood coagulation but also functions as a signal transduction receptor. TF expression in breast cancer is associated with higher tumor grade, metastasis and ...poor survival. The role of TF signaling on the early phases of metastasis has never been addressed. Here, we show an association between TF expression and metastasis as well as cancer stemness in 574 breast cancer patients. In preclinical models, blockade of TF signaling inhibited metastasis tenfold independent of primary tumor growth. TF blockade caused a reduction in epithelial-to-mesenchymal-transition, cancer stemness and expression of the pro-metastatic markers Slug and SOX9 in several breast cancer cell lines and in ex vivo cultured tumor cells. Mechanistically, TF forms a complex with β1-integrin leading to inactivation of β1-integrin. Inhibition of TF signaling induces a shift in TF-binding from α3β1-integrin to α6β4 and dictates FAK recruitment, leading to reduced epithelial-to-mesenchymal-transition and tumor cell differentiation. In conclusion, TF signaling inhibition leads to reduced pro-metastatic transcriptional programs, and a subsequent integrin β1 and β4-dependent reduction in metastasic dissemination.
Neutrophil extracellular traps (NETs) have been implicated in several hallmarks of cancer. Among the protumor effects, NETs promote epithelial-mesenchymal transition (EMT) in different cancer models. ...EMT has been linked to an enhanced expression of the clotting-initiating protein, tissue factor (TF), thus favoring the metastatic potential. TF may also exert protumor effects by facilitating the activation of protease-activated receptor 2 (PAR2). Herein, we evaluated whether NETs could induce TF expression in breast cancer cells and further promote procoagulant and intracellular signaling effects via the TF/PAR2 axis. T-47D and MCF7 cell lines were treated with isolated NETs, and samples were obtained for real-time PCR, flow cytometry, Western blotting, and plasma coagulation assays. In silico analyses were performed employing RNA-seq data from breast cancer patients deposited in The Cancer Genome Atlas (TCGA) database. A positive correlation was observed between neutrophil/NETs gene signatures and TF gene expression. Neutrophils/NETs gene signatures and PAR2 gene expression also showed a significant positive correlation in the bioinformatics model. In vitro analysis showed that treatment with NETs upregulated TF gene and protein expression in breast cancer cell lines. The inhibition of ERK/JNK reduced the TF gene expression induced by NETs. Remarkably, the pharmacological or genetic inhibition of the TF/PAR2 signaling axis attenuated the NETs-induced expression of several protumor genes. Also, treatment of NETs with a neutrophil elastase inhibitor reduced the expression of metastasis-related genes. Our results suggest that the TF/PAR2 signaling axis contributes to the pro-cancer effects of NETs in human breast cancer cells.
The establishment of prothrombotic states during cancer progression is well reported but the precise mechanisms underlying this process remain elusive. A number of studies have implicated the ...presence of the clotting initiator protein, tissue factor (TF), in circulating tumor-derived extracellular vesicles (EVs) with thrombotic manifestations in certain cancer types. Tumor cells, as well as tumor-derived EVs, may activate and promote platelet aggregation by TF-dependent and independent pathways. Cancer cells and their secreted EVs may also facilitate the formation of neutrophil extracellular traps (NETs), which may contribute to thrombus development. Alternatively, the presence of polyphosphate (polyP) in tumor-derived EVs may promote thrombosis through a TF-independent route. We conclude that the contribution of EVs to cancer coagulopathy is quite complex, in which one or more mechanisms may take place in a certain cancer type. In this context, strategies that could attenuate the crosstalk between the proposed pro-hemostatic routes could potentially reduce cancer-associated thrombosis.
Glioblastoma (GBM) patients have one of the highest risks of venous thromboembolism (VTE), which is even further increased upon treatment with chemotherapy. Tissue factor (TF) is the initiator of the ...extrinsic coagulation pathway and expressed by GBM cells. In this study, we aimed to examine the effect of routinely used chemotherapeutic agents Temozolomide (TMZ) and Lomustine (LOM) on TF procoagulant activity and expression in GBM cells in vitro. Three human GBM cell lines (U-251, U-87, U-118) were exposed to 100 µM TMZ or 30 µM LOM for 72 h. TF procoagulant activity was assessed via an FXa generation assay and TF gene and protein expression through qPCR and Western blotting. The externalization of phosphatidylserine (PS) was studied using Annexin V flow cytometry. Treatment with TMZ and LOM resulted in increased procoagulant activity in all cell lines. Furthermore, both agents induced procoagulant activity in the supernatant and tumor-cell-secreted extracellular vesicles. In line, TF gene and protein expression were increased upon TMZ and LOM treatment. Additionally, PS externalization and induction of inflammatory-associated genes were observed. Overall, the chemotherapeutic modalities TMZ and LOM induced procoagulant activity and increased TF gene and protein expression in all GBM cell lines tested, which may contribute to the increased VTE risk observed in GBM patients undergoing chemotherapy.
Abstract Background Cholecystectomy remains the gold standard treatment of cholecystitis. Endoscopic treatment of cholecystitis includes transpapillary gallbladder drainage. Recently, endoscopic ...ultrasound-guided transmural drainage of the gallbladder (EUS-GBD) has been reported. This study reports the cumulative experience of an international group performing EUS-GBD. Methods Cases of EUS-GBD from January 2012 to November 2013 from 3 tertiary-care institutions were captured in a registry. Patient demographics, disease characteristics, procedural and clinical outcomes were recorded. Results 35 patients (15 malignant, 20 benign) were included. Median age was 81 years (SD = 13.76 years), sixteen (46%) were males. Median follow-up was 91.5 days (SD = 157 days). Transmural access was obtained from the stomach ( n = 17) or duodenum ( n = 18). Stents placed included plastic ( n = 6), metal ( n = 20), or combination ( n = 7). Technical success was achieved in 91.4% ( n = 32). Immediate adverse events (14%) included: bleeding, stent migration, cholecystitis and hemoperitoneum. Delayed adverse events (11%) included abscess formation and recurrence of cholecystitis. Long-term clinical success rate was 89%. Stent type and puncture site were not associated with immediate ( p = 0.88, p = 0.62), or long-term ( p = 0.47, p = 0.27) success. Conclusions EUS-GBD appears to be feasible, safe, and effective. Prospective studies are needed to confirm these findings and identify the best technique to use. Clinical trial registration NCT01522573.
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