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Clinically relevant brain metastases (BMs) frequently form in cancer patients, with limited options for effective treatment. Circulating cancer cells must first permanently arrest in brain microvessels to colonize the brain, but the critical factors in this process are not well understood. Here, in vivo multiphoton laser-scanning microscopy of the entire brain metastatic cascade allowed unprecedented insights into how blood clot formation and von Willebrand factor (VWF) deposition determine the arrest of circulating cancer cells and subsequent brain colonization in mice. Clot formation in brain microvessels occurred frequently (>95%) and specifically at intravascularly arrested cancer cells, allowing their long-term arrest. An extensive clot embedded ∼20% of brain-arrested cancer cells, and those were more likely to successfully extravasate and form a macrometastasis. Mechanistically, the generation of tissue factor-mediated thrombin by cancer cells accounted for local activation of plasmatic coagulation in the brain. Thrombin inhibition by treatment with low molecular weight heparin or dabigatran and an anti-VWF antibody prevented clot formation, cancer cell arrest, extravasation, and the formation of brain macrometastases. In contrast, tumor cells were not able to directly activate platelets, and antiplatelet treatments did reduce platelet dispositions at intravascular cancer cells but did not reduce overall formation of BMs. In conclusion, our data show that plasmatic coagulation is activated early by intravascular tumor cells in the brain with subsequent clot formation, which led us to discover a novel and specific mechanism that is crucial for brain colonization. Direct or indirect thrombin and VWF inhibitors emerge as promising drug candidates for trials on prevention of BMs., (© 2021 by The American Society of Hematology.)

Background: Livedoid vasculopathy is a thrombotic skin disease characterised by recurrent occlusion of the cutaneous microcirculation in lower extremities, which results in skin infarctions with painful ulcerations and irreversible scar formation. Rivaroxaban is a direct factor Xa inhibitor that prevents thrombus formation. We investigated whether rivaroxaban is effective for the treatment of livedoid vasculopathy., Methods: We did this single-arm, open-label, multicenter, phase 2a, proof-of concept trial at three university hospitals in Germany. Patients with livedoid vasculopathy and a minimum pain score of 40 on the visual analogue scale were eligible to participate. Patients received oral rivaroxaban tablets for 12 weeks at an initial dose of 10 mg twice per day, which was reduced to once per day if a reduction of pain by 50% on the visual analogue scale was achieved. Subcutaneous enoxaparin at 1 mg per kg bodyweight once or twice per day was allowed as a backup treatment in case of insufficient efficacy and increased pain. The primary endpoint was change in pain on the visual analogue scale from baseline to 12 weeks. Efficacy was assessed in the intention-to-treat population and safety was assessed in all patients who received at least one dose of study drug. This trial is registered with the EU Clinical Trials Register, EudraCT number 2012-000108-13-DE, and is closed to new participants., Findings: Between Dec 28, 2012, and April 24, 2014, 36 patients were screened, 28 patients were recruited for the study, and 25 patients received treatment. During treatment, five patients dropped out of the study because of withdrawal of consent (one patient), lack of compliance (one patient), violation of inclusion criteria (two patients), and a serious adverse event (one patient). Median pain on the visual analogue scale decreased from 65·0 (IQR 52·0-78·0) at baseline to 6·0 (1·0-14·0) after 12 weeks of treatment (p<0·0001). Six of the 20 patients required additional treatment with enoxaparin. Eight treatment-related adverse events were recorded in six (24%) of the 25 patients: five cases of menorrhagia including one classified as both menorrhagia and dysmenorrhoea, one case of dyspnoea, and one case of gingival bleeding. The only serious adverse reaction to rivaroxaban during the study was one case of menorrhagia in a patient with concomitant endometriosis, which resulted in study discontinuation., Interpretation: Rivaroxaban seems to effectively reduce pain in livedoid vasculopathy. Therefore we suggest that rivaroxaban with enoxaparin as a backup treatment is a suitable treatment option for patients with livedoid vasculopathy., Funding: Deutsche Forschungsgemeinschaft and Bayer Vital., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Simple Summary: The interactions between circulating tumor cells (CTCs) and plasma proteins are critical for hematogenous metastasis, and understanding the molecular mechanisms behind these interactions can improve liquid-biopsy-based diagnostics and cancer therapies. This review summarizes recent literature on the surface molecules of CTCs that interact with coagulation proteins and their biological and clinical relevance. It also discusses future research directions to expand our knowledge of the CTC interactome, which can lead to the discovery of new molecular markers for diagnostics and additional targets for cancer therapies. Cancer metastasis is a complex process. After their intravasation into the circulation, the cancer cells are exposed to a harsh environment of physical and biochemical hazards. Whether circulating tumor cells (CTCs) survive and escape from blood flow defines their ability to metastasize. CTCs sense their environment with surface-exposed receptors. The recognition of corresponding ligands, e.g., fibrinogen, by integrins can induce intracellular signaling processes driving CTCs' survival. Other receptors, such as tissue factor (TF), enable CTCs to induce coagulation. Cancer-associated thrombosis (CAT) is adversely connected to patients' outcome. However, cancer cells have also the ability to inhibit coagulation, e.g., through expressing thrombomodulin (TM) or heparan sulfate (HS), an activator of antithrombin (AT). To that extent, individual CTCs can interact with plasma proteins, and whether these interactions are connected to metastasis or clinical symptoms such as CAT is largely unknown. In the present review, we discuss the biological and clinical relevance of cancer-cell-expressed surface molecules and their interaction with plasma proteins. We aim to encourage future research to expand our knowledge of the CTC interactome, as this may not only yield new molecular markers improving liquid-biopsy-based diagnostics but also additional targets for better cancer therapies. [ABSTRACT FROM AUTHOR]

Ingenol mebutate (IM) is highly effective in the treatment of human papillomavirus (HPV)-induced anogenital warts (AGW) leading to fast ablation within hours. However, the exact mode of action is still largely unknown. We performed dermoscopy, in vivo confocal microscopy (CLM), histology, immunohistochemistry, and immunofluorescence to gain insights in mechanisms of IM treatment in AGW. In addition, we used in vitro assays (ELISA, HPV-transfection models) to further investigate in vivo findings. IM treatment leads to a strong recruitment of neutrophils with thrombosis of small skin vessels within 8 h, in a sense of immunothrombosis. In vivo and in vitro analyses showed that IM supports a prothrombotic environment by endothelial cell activation and von Willebrand factor (VWF) secretion, in addition to induction of neutrophil extracellular traps (NETosis). IM superinduces CXCL8/IL-8 expression in HPV-E6/E7 transfected HaCaT cells when compared to non-infected keratinocytes. Rapid ablation of warts after IM treatment can be well explained by the observed immunothrombosis. This new mechanism has so far only been observed in HPV-induced lesions and is completely different from the mechanisms we see in the treatment of transformed keratinocytes in actinic keratosis. Our initial findings indicate an HPV-specific effect, which could be also of interest for the treatment of other HPV-induced lesions. Larger studies are now needed to further investigate the potential of IM in different HPV tumors. [ABSTRACT FROM AUTHOR]

Malignant cells elicit a chronic hemostatic activation in disease progress. This procoagulant activity does not only bear a risk for thromboembolism but also facilitates tumor growth and dissemination. An elevated plasma D-dimer level indicates an activated coagulation and fibrinolysis. In this study, the association of D-dimer levels with clinicopathological parameters and patients outcome in melanoma was investigated analyzing in total 533 melanoma patients retrospectively. Using the cut-off point of 0.6 mg/L D-dimer 145 of the total 533 patients (27.2%) were identified with elevated plasma D-dimer levels. This increased D-dimer level positively correlated with tumor thickness ( p = 0.0003), lymph node invasion ( p = 0.0004) and metastatic state ( p <0.0001). To assess the association of D-dimer levels with progression-free survival (PFS) and overall survival (OS), long-rank test and the Cox proportional hazard model was performed. Univariate analyses revealed that elevated D-dimer levels were significantly associated with decreased PFS (HR:2.89, 95% CI (2.07-7.56), p < 0.0001) and OS (HR:2.22, 95% CI (1.06-4.57), p = 0.035). Moreover, multivariate analyses identified elevated D-dimer levels being associated with poor disease outcome (PFS:HR:2.47, 95% CI (1.23-4.98), p = 0.012; OS:HR:2.01, 95% CI (0.09-4.45), p = 0.087). Additionally, D-dimer levels were significantly increased in terminal stage patients when comparing plasma levels 0-8 versus 24-48 weeks before death ( p = 0.0003). In summary, this study presents multiple evidence that elevated D-dimer levels in melanoma patients associate with poor prognosis and therefore plasma levels of D-dimers could reveal a more aggressive phenotype of melanoma and may guide the management of anti-melanoma treatment including the concept of an anti-coagulatory therapy in tumor patients. [ABSTRACT FROM AUTHOR]

Primary hemostasis and blood clotting is known to be influenced by the red blood cell volume fraction (hematocrit) in blood. Depressed or elevated levels of red blood cells can lead to vascular perfusion problems ranging from bleeding to thrombus formation. The early stage of hemostasis and thus blood clotting in all vessel sections from the arterial to the venous system involves the adhesion of platelets to von Willebrand factor. Here we present experimental and theoretical results showing that the adhesion probability of platelets to von Willebrand factor is strongly and nonlinearly dependent on hematocrit and flow rate. Interestingly, the actual binding forces are not markedly different, which suggest that the origin of such behavior is in the distribution of platelets. Using hydrodynamic simulations of a simple model, we explicitly show that the higher the hematocrit and the flow rate, the larger the amount of platelets residing close to the wall. Our simulation results, which are in excellent agreement with the experimental observations, explain why such phenomena occur. We believe that the nonhomogeneous red blood cell distribution as well as the shear dependent hydrodynamic interaction is key for the accumulation of platelets on the vessel wall. The work we present here is an important step forward from our earlier work on single molecules and extends into the collective cellular behavior of whole blood. It sheds new light on the correlation between hematocrit and the initial steps in hemostasis and thrombosis, and outlines advances for the treatment of vascular diseases associated with high levels of red blood cells. These results are not only highly relevant for the field of hemostasis and the physics of blood clotting but are also of powerful impact in applied science most obviously in drug delivery and colloidal science. [ABSTRACT FROM AUTHOR]