Several studies reported a central role of the endothelin type A receptor (ETAR) in tumor progression leading to the formation of metastasis. Here, we investigated the in vitro and in vivo anti-tumor effects of the FDA-approved ETAR antagonist, Ambrisentan, which is currently used to treat patients with pulmonary arterial hypertension. In vitro, Ambrisentan inhibited both spontaneous and induced migration/invasion capacity of different tumor cells (COLO-357 metastatic pancreatic adenocarcinoma, OvCar3 ovarian carcinoma, MDA-MB-231 breast adenocarcinoma, and HL-60 promyelocytic leukemia). Whole transcriptome analysis using RNAseq indicated Ambrisentan’s inhibitory effects on the whole transcriptome of resting and PAR2-activated COLO-357 cells, which tended to normalize to an unstimulated profile. Finally, in a pre-clinical murine model of metastatic breast cancer, treatment with Ambrisentan was effective in decreasing metastasis into the lungs and liver. Importantly, this was associated with a significant enhancement in animal survival. Taken together, our work suggests a new therapeutic application for Ambrisentan in the treatment of cancer metastasis.

BackgroundThere is growing evidence that nervous and immune system communicate with each other through soluble mediators.1 Immune cells such as neutrophils express muscarinic acetylcholine receptors (mAChR), which are neuroimmune receptors and highly prevalent in the nervous system.2 Aberrant neutrophil functioning plays an important role in various autoimmune diseases. Dysregulation of neutrophil immune responses such as oxidative burst and migration is one of the key mechanisms leading to tissue damage in autoimmune diseases.3 However, the impact of mAChR activation on neutrophils remains contradictory.ObjectivesWe aimed to determine effects of muscarinic receptor activation on development and functions of neutrophils.MethodsNeutrophils were isolated from peripheral blood of healthy donors by dextran sedimentation. After one hour in the absence or presence of the natural ligand acetylcholine (Ach) (10nM-100μM) or the muscarinic agonist oxotremorine-m (oxo-m) (10nM-100μM), neutrophil respiratory burst was analyzed by dihydrorhodamine (DHR) flow cytometry assay and migration assessed by transwell assay in response to N-formylmethionyl-leucyl-phenylalanine (fMLP). Cells that migrated were quantified by flow cytometry. To analyze the effects mAChR activation on the development of neutrophils, HL-60 cells were incubated in the presence of DMSO (1%), oxo-m (100μM) or DMSO plus oxo-m. After 6 days, cells were harvested and expression of maturation markers (CD15, CD63 and CD16) as well as mAChR (M1-M5) were measured by flow cytometry.ResultsWe observed no effects of mAChR activation on the respiratory burst of neutrophils. However, both ACh and oxo-m inhibited neutrophil migration in a dose-dependent manner, but with peculiar differences. By increasing acetylcholine concentrations, we observed a reduction of neutrophil migration in a directly proportional manner. On the other hand, while the lowest dose (10nM) of oxo-m inhibited migration most effectively, the increase of oxo-m showed inversely proportional effects on neutrophil migration. Thus, we aimed to investigate, if the highest dose of oxo-m has a different effect on neutrophils ontogeny. In agreement with the results obtained with neutrophils, the incubation of HL-60 cells with the highest dose of oxo-m showed no effect on oxidative burst and migration and induced no changes in the expression of mAChRs (M1-M5), CD16 and CD63 in HL-60 cells. However, we observed that it resulted in significantly increased surface levels of the neutrophilic lineage marker CD15.ConclusionsOur data indicate a differential activation of mAChR affecting different steps of neutrophil ontogeny. Considering this finding, abnormalities in the activation of muscarinic receptors as have been observed in autoimmune diseases might contribute to neutrophil dysfunction and need further investigation.References Blalock, J. E. The syntax of immune-neuroendocrine communication. Immunol Today 15, 504–511 (1994).Milara et al. Non-neuronal cholinergic system contributes to corticosteroid resistance i...

"Allocation of health resources towards the treatment of patients with COVID-19 may affect the quality of care for non-COVID-19 patients. Several medical societies representing cancer health professionals have issued statements on priority setting in cancer care in the wake of the Sars-CoV-2 outbreak (1, 2). However, there is a lack of empirical data on how resources are prioritized in cancer care and which criteria are taken into consideration by those involved in decision making. In this paper we will present findings from qualitative interviews conducted with oncologists in Germany between February and July 2021. Transcripts of interviews are analysed following principles of qualitative content analysis based on Kuckartz (3). According to preliminary analysis of the first five interviews conducted three major topics emerge: 1. Experiences with scarcity regarding selected diagnostic procedures and treatment. 2. Material and procedural criteria for priority setting and decisions on deviations of standards of care. 3. Effects of priority setting on coping and psycho-social support. We will discuss findings with regards to their possible contribution to an empirical and normative founded guidance for priority setting in cancer care in times of Sars-CoV-2 outbreak and comparable events. 1. Deutsche Gesellschaft für Hämatologie und Onkologie. Coronavirus-Infektion (COVID-19) bei Patienten mit Blut- und rebserkrankungen. https://www.onkopedia.com/de/onkopedia/guidelines/coronavirus-infektion-covid-19-bei-patient-innen-mit-blut-und-krebserkrankungen/@@guideline/html/index.html 2. Marron JM, Joffe S, Jagsi R et al. Ethics and Resource Scarcity: ASCO Recommendations for the Oncology Community During the COVID19 Pandemic. J Clin Onc. April 28 2020, doi:10.1200/JCO.20.00960 3. Kuckartz, U. (2018). Qualitative Inhaltsanalyse. Methoden, Praxis, Computer¬unterstützung (4th ed.). Beltz Juventa. "

BackgroundEndothelin-1 type A receptor (ETAR) antagonists (e.g. ambrisentan) are currently approved by the U.S Food and Drug administration, representing a well-tolerated treatment of pulmonary arterial hypertension (PAH)[1] for patients with connective tissue diseases such as systemic sclerosis (SSc). Noteworthy, increased numbers of infiltrating neutrophils have been associated with worse clinical outcome in PAH patients. In another context, several studies have reported that endothelin-1 and its receptor ETAR also play a central role in the development of tumour cell invasion and metastasis. However, the effects of ETAR antagonists on migration of neutrophils and tumour cells remain to be determined.ObjectivesThe objective was to analyse the effects of two ETAR antagonists on migration of neutrophils and tumour cell lines.MethodsThe migratory ability of peripheral neutrophils from healthy donors (HD) and different tumour cell lines (myeloid leukaemia HL60 cells and human pancreatic adenocarcinoma COLO357 cells) was analysed in response to N-Formylmethionyl-leucyl-phenylalanine (FMLP) or Protease-activated receptor 2 (Par-2) agonist. Because it has been shown before [2], IgGs from HD and SSc patients were used as additional stimulus for migration. Neutrophils and HL60 cells were preincubated (1h) with sitaxentan or ambrisentan, respectively, before being tested for migration (1h) using the Transwell assay. COLO357 cells were incubated (48h) in the presence of sitaxentan and migration was tested in the Oris Pro Cell assay. Migration was analysed by automatic cell counting or digital photo analysis and a migration index was calculated.ResultsSitaxentan and/or ambrisentan significantly blocked the migration of neutrophils and tumour cell lines. In more detail, neutrophil migration in response to FMLP, being set to 100%, was completely inhibited by sitaxentan (0,46%). Further, neutrophil migration in response to IgGs from HD and SSc patients was induced equally, again being set to 100%. In the presence of sitaxentan migration was reduced to 60%, respectively. In DMSO-differentiated HL60 cells the migratory capacity in response to FMLP (100%) was reduced to 66% by ambrisentan and to 14% by sitaxentan. Moreover, in the presence of sitaxentan and a Par-2 agonist the migratory ability of COLO357 cells was significantly decreased to 89% compared to Par-2 agonist only, being set to 100%.ConclusionsOur results suggest a pivotal and non-redundant role of ETAR in cell migration, which needs further clarification in order to repurpose the use of ETAR inhibitors. Therapeutic switching of ETAR antagonists from PAH to cancer therapies is a promising adjuvant therapy.References Waxman AB. A review of sitaxsentan sodium in patients with pulmonary arterial hypertension. Vasc Health Risk Manag 2007;3:151–7.Kill A, Tabelin C, Undeutsch R, et al. Autoantibodies to angiotensin and endothelin receptors in systemic sclerosis induce cellular and systemic events associated with disease pathogenesis. Arthritis R&T, 2014, 16:R29. Disclosure ...