Histamine H2-receptor antagonism improves conduit artery endothelial function and reduces plasma aldosterone level without lowering arterial blood pressure in angiotensin II-hypertensive mice.

Aldosterone through the mineralocorticoid receptor MR has detrimental effects on cardiovascular disease. It reduces the bioavailability of nitric oxide and impairs endothelium-dependent vasodilatation. In resistance arteries, aldosterone impairs the sensitivity of vascular smooth muscle cells to nitric oxide by promoting the local secretion of histamine which activates H2 receptors. The present experiments tested in vivo and ex vivo the hypothesis that systemic H2-receptor antagonism reduces arterial blood pressure and improves vasodilatation in angiotensin II-induced chronic hypertension. Hypertension was induced by intravenous infusion of angiotensin II (60 ng kg-1 min-1) in conscious, unrestrained mice infused concomitantly with the H2-receptor antagonist ranitidine (27.8 µg kg-1 min-1) or vehicle for 24 days. Heart rate and arterial blood pressure were recorded by indwelling arterial catheter. Resistance (mesenteric) and conductance (aortae) arteries were harvested for perfusion myography and isometric tension recordings by wire myography, respectively. Plasma was analyzed for aldosterone concentration. ANGII infusion resulted in elevated arterial blood pressure and while in vivo treatment with ranitidine reduced plasma aldosterone concentration, it did not reduce blood pressure. Ranitidine improved ex vivo endothelial function (acetylcholine 10-9 to 10-6 mol L-1) in mesenteric resistance arteries. This was abolished by ex vivo treatment with aldosterone (10-9 mol L-1, 1 h). In aortic segments, in vivo ranitidine treatment impaired relaxation. Activation of histamine H2 receptors promotes aldosterone secretion, does not affect arterial blood pressure, and protects endothelial function in conduit arteries but promotes endothelial dysfunction in resistance arteries during angiotensin II-mediated hypertension. Aldosterone contributes little to angiotensin II-induced hypertension in mice.

Structure, Function, and Pharmacology of Glutamate Receptor Ion Channels.

Many physiologic effects of l-glutamate, the major excitatory neurotransmitter in the mammalian central nervous system, are mediated via signaling by ionotropic glutamate receptors (iGluRs). These ligand-gated ion channels are critical to brain function and are centrally implicated in numerous psychiatric and neurologic disorders. There are different classes of iGluRs with a variety of receptor subtypes in each class that play distinct roles in neuronal functions. The diversity in iGluR subtypes, with their unique functional properties and physiologic roles, has motivated a large number of studies. Our understanding of receptor subtypes has advanced considerably since the first iGluR subunit gene was cloned in 1989, and the research focus has expanded to encompass facets of biology that have been recently discovered and to exploit experimental paradigms made possible by technological advances. Here, we review insights from more than 3 decades of iGluR studies with an emphasis on the progress that has occurred in the past decade. We cover structure, function, pharmacology, roles in neurophysiology, and therapeutic implications for all classes of receptors assembled from the subunits encoded by the 18 ionotropic glutamate receptor genes. SIGNIFICANCE STATEMENT: Glutamate receptors play important roles in virtually all aspects of brain function and are either involved in mediating some clinical features of neurological disease or represent a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of this class of receptors will advance our understanding of many aspects of brain function at molecular, cellular, and system levels and provide new opportunities to treat patients.

Predicting molecular properties of α-synuclein using force fields for intrinsically disordered proteins.

Independent force field validation is an essential practice to keep track of developments and for performing meaningful Molecular Dynamics simulations. In this work, atomistic force fields for intrinsically disordered proteins (IDP) are tested by simulating the archetypical IDP α-synuclein in solution for 2.5 µs. Four combinations of protein and water force fields were tested: ff19SB/OPC, ff19SB/TIP4P-D, ff03CMAP/TIP4P-D, and a99SB-disp/TIP4P-disp, with four independent repeat simulations for each combination. We compare our simulations to the results of a 73 µs simulation using the a99SB-disp/TIP4P-disp combination, provided by D. E. Shaw Research. From the trajectories, we predict a range of experimental observations of α-synuclein and compare them to literature data. This includes protein radius of gyration and hydration, intramolecular distances, NMR chemical shifts, and 3 J-couplings. Both ff19SB/TIP4P-D and a99SB-disp/TIP4P-disp produce extended conformational ensembles of α-synuclein that agree well with experimental radius of gyration and intramolecular distances while a99SB-disp/TIP4P-disp reproduces a balanced α-synuclein secondary structure content. It was found that ff19SB/OPC and ff03CMAP/TIP4P-D produce overly compact conformational ensembles and show discrepancies in the secondary structure content compared to the experimental data.

In vitro ADME characterization of a very potent 3-acylamino-2-aminopropionic acid-derived GluN2C-NMDA receptor agonist and its ester prodrugs.

The GluN2C subunit exists predominantly, but not exclusively in NMDA receptors within the cerebellum. Antagonists such as UBP1700 and positive allosteric modulators including PYD-106 and 3-acylamino-2-aminopropionic acid derivatives such as UA3-10 ((R)-2-amino-3-{[5-(2-bromophenyl)thiophen-2-yl]carboxamido}propionic acid) represent promising tool compounds to investigate the role of GluN2C-containing NMDA receptors in the signal transduction in the brain. However, due to its high polarity the bioavailability and CNS penetration of the amino acid UA3-10 are expected to be rather low. Herein, three ester prodrugs 12a-c of the NMDA receptor glycine site agonist UA3-10 were prepared and pharmacokinetically characterized. The esters 12a-c showed higher lipophilicity (higher logD 7.4 values) than the acid UA3-10 but almost the same binding at human serum albumin. The acid UA3-10 was rather stable upon incubation with mouse liver microsomes and NADPH, but the esters 12a-c were fast hydrolyzed to afford the acid UA3-10. Incubation with pig liver esterase and mouse serum led to rapid hydrolysis of the esters 12a-c. The isopropyl ester 12c showed a promising logD 7.4 value of 3.57 and the highest stability in the presence of pig liver esterase and mouse serum. These results demonstrate that ester prodrugs of UA3-10 can potentially afford improved bioavailability and CNS penetration.

Automatic Optimization of Lipid Models in the Martini Force Field Using SwarmCG.

After two decades of continued development of the Martini coarse-grained force field (CG FF), further refinment of the already rather accurate Martini lipid models has become a demanding task that could benefit from integrative data-driven methods. Automatic approaches are increasingly used in the development of accurate molecular models, but they typically make use of specifically designed interaction potentials that transfer poorly to molecular systems or conditions different than those used for model calibration. As a proof of concept, here, we employ SwarmCG, an automatic multiobjective optimization approach facilitating the development of lipid force fields, to refine specifically the bonded interaction parameters in building blocks of lipid models within the framework of the general Martini CG FF. As targets of the optimization procedure, we employ both experimental observables (top-down references: area per lipid and bilayer thickness) and all-atom molecular dynamics simulations (bottom-up reference), which respectively inform on the supra-molecular structure of the lipid bilayer systems and on their submolecular dynamics. In our training sets, we simulate at different temperatures in the liquid and gel phases up to 11 homogeneous lamellar bilayers composed of phosphatidylcholine lipids spanning various tail lengths and degrees of (un)saturation. We explore different CG representations of the molecules and evaluate improvements a posteriori using additional simulation temperatures and a portion of the phase diagram of a DOPC/DPPC mixture. Successfully optimizing up to ∼80 model parameters within still limited computational budgets, we show that this protocol allows the obtainment of improved transferable Martini lipid models. In particular, the results of this study demonstrate how a fine-tuning of the representation and parameters of the models may improve their accuracy and how automatic approaches, such as SwarmCG, may be very useful to this end.

Sodium-glucose cotransporter 2 inhibitors and risk of nephrolithiasis.

AIMS/HYPOTHESIS: Sodium-glucose cotransporter 2 inhibitors (SGLT2Is) may reduce nephrolithiasis risk by increasing urine flow. We aimed to investigate whether initiation of SGLT2I was associated with reduced nephrolithiasis risk. METHODS: We conducted an active-comparator new-user cohort study using the Danish health registries in the period 11 November 2012 to 31 December 2018. Individuals aged ≥40 years initiating SGLT2Is or glucagon-like peptide-1 receptor agonists (GLP1 RAs) were followed from treatment initiation until an inpatient or outpatient diagnosis of nephrolithiasis, death, emigration or end of study. New users of SGLT2Is were matched 1:1 on propensity scores to new users of GLP1 RAs. In supplementary analyses, risk of recurrent nephrolithiasis was assessed in individuals with a history of nephrolithiasis before treatment initiation. RESULTS: We identified 24,290 and 19,576 eligible users of SGLT2Is and GLP1 RAs, respectively. After matching, 12,325 patient pairs remained. The median age was 61 years and median follow-up was 2.0 years. The nephrolithiasis rate was 2.0 per 1000 person-years in SGLT2I initiators compared with 4.0 per 1000 person-years in GLP1 RA initiators, with a rate difference of -1.9 per 1000 person-years (95% CI -2.8, -1.0) and an HR of 0.51 (95% CI 0.37, 0.71). For recurrent nephrolithiasis (n = 731 patient pairs), the rate difference was -17 per 1000 person-years (95% CI -33, -1.5) and the HR was 0.68 (95% CI 0.48, 0.97). CONCLUSIONS/INTERPRETATION: Initiation of treatment with SGLT2Is was associated with a clinically significant reduced risk of incident and recurrent nephrolithiasis.

Brain tumor vessels-a barrier for drug delivery.

Cancer treatment remains a challenge due to a high level of intra- and intertumoral heterogeneity and the rapid development of chemoresistance. In the brain, this is further hampered by the blood-brain barrier that reduces passive diffusion of drugs to a minimum. Tumors grow invasively and form new blood vessels, also in brain tissue where remodeling of pre-existing vasculature is substantial. The cancer-associated vessels in the brain are considered leaky and thus could facilitate the transport of chemotherapeutic agents. Yet, brain tumors are extremely difficult to treat, and, in this review, we will address how different aspects of the vasculature in brain tumors contribute to this.

Urinary tract infections and risk of squamous cell carcinoma bladder cancer: A Danish nationwide case-control study.

Schistosoma haematobium infection can lead to squamous cell carcinomas (SCC) of the bladder. Whether this also applies to more common urinary tract infections (UTIs) is unclear. We therefore aimed to investigate the association between UTIs, reflected by the use of specific antibiotics and risk of SCC of the bladder. We conducted a Danish nationwide case-control study and identified histologically verified bladder cancer cases (2000-2015; n = 12,271) and age- and sex-matched cancer-free controls. We computed odds ratios (ORs) with 95% confidence intervals (CI) associating the use of UTI-specific antibiotics with SCC bladder cancer, using conditional logistic regression. We applied a 2-year lag-time to minimize reverse causation. To aid interpretation, similar analyses were performed for other bladder cancer types and other antibiotics. We identified 333 SCC cases (2.7% of all bladder cancers). Compared to no use (0-1 prescription), high-use (≥10 prescriptions) of UTI-specific antibiotics was associated with SCC with an OR of 11.4 (CI 7.6-17.2) and a clear dose-response pattern (ptrend < 0.001). Use of phenoxymethylpenicillin, an antibiotic not used against UTIs, was not associated with SCC after adjustment for use of UTI-specific antibiotics (OR 0.5). Furthermore, UTI-specific antibiotic use was not associated with urothelial carcinomas (n = 11,029; OR 1.13; CI 0.97-1.32). Excluding patients with known urogenital disease did not influence the SCC estimates (overall OR 10.8; CI 6.2-18.9). Data on smoking were lacking, however, a quantitative bias analysis suggested this to be of limited importance. In conclusion, common UTIs are strong, dose-dependent and specifically associated with risk of SCC of the bladder.

Structural basis of subunit selectivity for competitive NMDA receptor antagonists with preference for GluN2A over GluN2B subunits.

NMDA-type glutamate receptors are ligand-gated ion channels that contribute to excitatory neurotransmission in the central nervous system (CNS). Most NMDA receptors comprise two glycine-binding GluN1 and two glutamate-binding GluN2 subunits (GluN2A-D). We describe highly potent (S)-5-[(R)-2-amino-2-carboxyethyl]-4,5-dihydro-1H-pyrazole-3-carboxylic acid (ACEPC) competitive GluN2 antagonists, of which ST3 has a binding affinity of 52 nM at GluN1/2A and 782 nM at GluN1/2B receptors. This 15-fold preference of ST3 for GluN1/2A over GluN1/2B is improved compared with NVP-AAM077, a widely used GluN2A-selective antagonist, which we show has 11-fold preference for GluN1/2A over GluN1/2B. Crystal structures of the GluN1/2A agonist binding domain (ABD) heterodimer with bound ACEPC antagonists reveal a binding mode in which the ligands occupy a cavity that extends toward the subunit interface between GluN1 and GluN2A ABDs. Mutational analyses show that the GluN2A preference of ST3 is primarily mediated by four nonconserved residues that are not directly contacting the ligand, but positioned within 12 Å of the glutamate binding site. Two of these residues influence the cavity occupied by ST3 in a manner that results in favorable binding to GluN2A, but occludes binding to GluN2B. Thus, we reveal opportunities for the design of subunit-selective competitive NMDA receptor antagonists by identifying a cavity for ligand binding in which variations exist between GluN2A and GluN2B subunits. This structural insight suggests that subunit selectivity of glutamate-site antagonists can be mediated by mechanisms in addition to direct contributions of contact residues to binding affinity.

Functional and pharmacological properties of triheteromeric GluN1/2B/2D NMDA receptors.

KEY POINTS: Triheteromeric NMDA receptors contain two GluN1 and two distinct GluN2 subunits and mediate excitatory neurotransmission in the CNS. Triheteromeric GluN1/2B/2D receptors have functional properties intermediate to those of diheteromeric GluN1/2B and GluN1/2D receptors. GluN1/2B/2D receptors are more sensitive to channel blockade by ketamine and memantine compared to GluN1/2B receptors in the presence of physiological Mg2+ . GluN2B-selective antagonists produce robust inhibition of GluN1/2B/2D receptors, and the GluN2B-selective positive allosteric modulator spermine enhances responses from GluN1/2B/2D but not GluN1/2A/2B receptors. These insights into the properties of triheteromeric GluN1/2B/2D receptors are necessary to appreciate their physiological roles in neural circuit function and the actions of therapeutic agents targeting NMDA receptors. ABSTRACT: Triheteromeric NMDA-type glutamate receptors that contain two GluN1 and two different GluN2 subunits contribute to excitatory neurotransmission in the adult CNS. In the present study, we report properties of the triheteromeric GluN1/2B/2D NMDA receptor subtype that is expressed in distinct neuronal populations throughout the CNS. We show that neither GluN2B, nor GluN2D dominate the functional properties of GluN1/2B/2D receptors because agonist potencies, open probability and the glutamate deactivation time course of GluN1/2B/2D receptors are intermediate to those of diheteromeric GluN1/2B and GluN1/2D receptors. Furthermore, channel blockade of GluN1/2B/2D by extracellular Mg2+ is intermediate compared to GluN1/2B and GluN1/2D, although GluN1/2B/2D is more sensitive to blockade by ketamine and memantine compared to GluN1/2B in the presence of physiological Mg2+ . Subunit-selective allosteric modulators have distinct activity at GluN1/2B/2D receptors, including GluN2B-selective antagonists, ifenprodil, EVT-101 and CP-101-606, which inhibit with similar potencies but with different efficacies at GluN1/2B/2D (∼65% inhibition) compared to GluN1/2B (∼95% inhibition). Furthermore, the GluN2B-selective positive allosteric modulator spermine enhances responses from GluN1/2B/2D but not GluN1/2A/2B receptors. We show that these key features of allosteric modulation of recombinant GluN1/2B/2D receptors are also observed for NMDA receptors in hippocampal interneurons but not CA1 pyramidal cells, which is consistent with the expression of GluN1/2B/2D receptors in interneurons and GluN1/2A/2B receptors in pyramidal cells. Altogether, we uncover previously unknown functional and pharmacological properties of triheteromeric GluN1/2B/2D receptors that can facilitate advances in our understanding of their physiological roles in neural circuit function and therapeutic drug actions.

Functional assessment of triheteromeric NMDA receptors containing a human variant associated with epilepsy.

KEY POINTS: NMDA receptors are neurotransmitter-gated ion channels that are critically involved in brain cell communication Variations in genes encoding NMDA receptor subunits have been found in a range of neurodevelopmental disorders. We investigated a de novo genetic variant found in patients with epileptic encephalopathy that changes a residue located in the ion channel pore of the GluN2A NMDA receptor subunit. We found that this variant (GluN2AN615K ) impairs physiologically important receptor properties: it markedly reduces Mg2+ blockade and channel conductance, even for receptors in which one GluN2AN615K is co-assembled with one wild-type GluN2A subunit. Our findings are consistent with the GluN2AN615K mutation being the primary cause of the severe neurodevelopmental disorder in carriers. ABSTRACT: NMDA receptors are ionotropic calcium-permeable glutamate receptors with a voltage-dependence mediated by blockade by Mg2+ . Their activation is important in signal transduction, as well as synapse formation and maintenance. Two unrelated individuals with epileptic encephalopathy carry a de novo variant in the gene encoding the GluN2A NMDA receptor subunit: a N615K missense variant in the M2 pore helix (GRIN2AC1845A ). We hypothesized that this variant underlies the neurodevelopmental disorders in carriers and explored its functional consequences by electrophysiological analysis in heterologous systems. We focused on GluN2AN615K co-expressed with wild-type GluN2 subunits in physiologically relevant triheteromeric NMDA receptors containing two GluN1 and two distinct GluN2 subunits, whereas previous studies have investigated the impact of the variant in diheteromeric NMDA receptors with two GluN1 and two identical GluN2 subunits. We found that GluN2AN615K -containing triheteromers showed markedly reduced Mg2+ blockade, with a value intermediate between GluN2AN615K diheteromers and wild-type NMDA receptors. Single-channel conductance was reduced by four-fold in GluN2AN615K diheteromers, again with an intermediate value in GluN2AN615K -containing triheteromers. Glutamate deactivation rates were unaffected. Furthermore, we expressed GluN2AN615K in cultured primary mouse cortical neurons, observing a decrease in Mg2+ blockade and reduction in current density, confirming that the variant continues to have significant functional impact in neuronal systems. Our results demonstrate that the GluN2AN615K variant has substantial effects on NMDA receptor properties fundamental to the roles of the receptor in synaptic plasticity, even when expressed alongside wild-type subunits. This work strengthens the evidence indicating that the GluN2AN615K variant underlies the disabling neurodevelopmental phenotype in carriers.

Properties of Triheteromeric N-Methyl-d-Aspartate Receptors Containing Two Distinct GluN1 Isoforms.

N-Methyl-d-aspartate (NMDA)-type glutamate receptors mediate excitatory synaptic transmission in the central nervous system and play critical roles in many neuronal processes. The physiologic roles of NMDA receptors are shaped by their functional properties, which are highly dependent on subunit composition. Most NMDA receptors are assembled from two GluN1 and two GluN2 subunits, but diversity in subunit composition is made possible by eight GluN1 splice variants (i.e., isoforms) and four distinct GluN2 subunits (GluN2A-D). We demonstrate using Förster resonance energy transfer and fluorescence lifetime imaging that GluN1-1a and GluN1-1b isoforms, which include or lack residues encoded by exon 5, form triheteromeric GluN1-1a/GluN1-1b/GluN2A (1a/1b/2A) and GluN1-1a/GluN1-1b/GluN2B (1a/1b/2B) receptors. We describe the selective expression of NMDA receptors containing two different GluN1 isoforms, and show that triheteromeric 1a/1b/2A and 1a/1b/2B receptors exhibit intermediate deactivation kinetics and pharmacological properties compared with the respective diheteromeric GluN1-1a/GluN1-1a/GluN2 and GluN1-1b/GluN1-1b/GluN2 receptors. These results highlight the intriguing possibility that neurons can finely tune NMDA receptor signaling by shifting the ratio of expressed GluN1-1a and GluN1-1b isoforms. Furthermore, we evaluate the contribution of channel pore residues to magnesium block and calcium permeability. These data point to the asymmetric contribution of pore residues in GluN1 and GluN2 to magnesium block, and reveal that a single copy of pore residues from GluN3 subunits strongly attenuates magnesium block and calcium permeability of NMDA receptors. Thus, the selective expression of NMDA receptors containing two distinct GluN1 isoforms provides new opportunities to study functional properties relevant to neuronal receptors.

Periarterial fat from two human vascular beds is not a source of aldosterone to promote vasoconstriction.

Mouse adipocytes have been reported to release aldosterone and reduce endothelium-dependent relaxation. It is unknown whether perivascular adipose tissue (PVAT) releases aldosterone in humans. The present experiments were designed to test the hypothesis that human PVAT releases aldosterone and induces endothelial dysfunction. Vascular reactivity was assessed in human internal mammary and renal segmental arteries obtained at surgery. The arteries were prepared with/without PVAT, and changes in isometric tension were measured in response to the vasoconstrictor thromboxane prostanoid receptor agonist U46619 and the endothelium-dependent vasodilator acetylcholine. The effects of exogenous aldosterone and of mineralocorticoid receptor (MR) antagonist eplerenone were determined. Aldosterone concentrations were measured by ELISA in conditioned media incubated with human adipose tissue with/without angiotensin II stimulation. Presence of aldosterone synthase and MR mRNA was examined in perirenal, abdominal, and mammary PVAT by PCR. U46619 -induced tension and acetylcholine-induced relaxation were unaffected by exogenous and endogenous aldosterone (addition of aldosterone and MR blocker) in mammary and renal segmental arteries, both in the presence and absence of PVAT. Aldosterone release from incubated perivascular fat was not detectable. Aldosterone synthase expression was not consistently observed in human adipose tissues in contrast to that of MR. Thus, exogenous aldosterone does not affect vascular reactivity and endothelial function in ex vivo human arterial segments, and the tested human adipose tissues have no capacity to synthesize/release aldosterone. In perspective, physiologically relevant effects of aldosterone on vascular function in humans are caused by systemic aldosterone originating from the adrenal gland.

Activity and safety of crizotinib in patients with alveolar soft part sarcoma with rearrangement of TFE3: European Organization for Research and Treatment of Cancer (EORTC) phase II trial 90101 'CREATE'.

Background: Alveolar soft part sarcoma (ASPS) is an orphan malignancy associated with a rearrangement of transcription factor E3 (TFE3), leading to abnormal MET gene expression. We prospectively assessed the efficacy and safety of the MET tyrosine kinase inhibitor crizotinib in patients with advanced or metastatic ASPS. Patients and methods: Eligible patients with reference pathology-confirmed ASPS received oral crizotinib 250 mg bd. By assessing the presence or absence of a TFE3 rearrangement, patients were attributed to MET+ and MET- sub-cohorts. The primary end point was the objective response rate (ORR) according to local investigator. Secondary end points included duration of response, disease control rate (DCR), progression-free survival (PFS), progression-free rate, overall survival (OS) and safety. Results: Among 53 consenting patients, all had a centrally confirmed ASPS and 48 were treated. A total of 45 were eligible, treated and assessable. Among 40 MET+ patients, 1 achieved a confirmed partial response (PR) that lasted 215 days and 35 had stable disease (SD) as best response (ORR: 2.5%, 95% CI 0.6% to 80.6%). Further efficacy end points in MET+ cases were DCR: 90.0% (95% CI 76.3% to 97.2%), 1-year PFS rate: 37.5% (95% CI 22.9% to 52.1%) and 1-year OS rate: 97.4% (95% CI 82.8% to 99.6%). Among 4 MET- patients, 1 achieved a PR that lasted 801 days and 3 had SD (ORR: 25.0%, 95% CI 0.6% to 80.6%) for a DCR of 100% (95% CI 39.8% to 100.0%). The 1-year PFS rate in MET- cases was 50% (95% CI 5.8% to 84.5%) and the 1-year OS rate was 75% (95% CI 12.8% to 96.1%). One patient with unknown MET status due to technical failure achieved SD but stopped treatment due to progression after 17 cycles. The most common crizotinib-related adverse events were nausea [34/48 (70.8%)], vomiting [22/48 (45.8%)], blurred vision [22/48 (45.8%)], diarrhoea (20/48 (41.7%)] and fatigue [19/48 (39.6%)]. Conclusion: According to European Organization for Research and Treatment of Cancer (EORTC) efficacy criteria for soft tissue sarcoma, our study demonstrated that crizotinib has activity in TFE3 rearranged ASPS MET+ patients. Clinical trial number: EORTC 90101, NCT01524926.

Identification of AICP as a GluN2C-Selective N-Methyl-d-Aspartate Receptor Superagonist at the GluN1 Glycine Site.

N-methyl-d-aspartate (NMDA)-type ionotropic glutamate receptors mediate excitatory neurotransmission in the central nervous system and are critically involved in brain function. NMDA receptors are also implicated in psychiatric and neurological disorders and have received considerable attention as therapeutic targets. In this regard, administration of d-cycloserine (DCS), which is a glycine site NMDA receptor agonist, can enhance extinction of conditioned fear responses. The intriguing behavioral effects of DCS have been linked to its unique pharmacological profile among NMDA receptor subtypes (GluN1/2A-D), in which DCS is a superagonist at GluN2C-containing receptors compared with glycine and a partial agonist at GluN2B-containing receptors. Here, we identify (R)-2-amino-3-(4-(2-ethylphenyl)-1H-indole-2-carboxamido)propanoic acid (AICP) as a glycine site agonist with unique GluN2-dependent differences in agonist efficacy at recombinant NMDA receptor subtypes. AICP is a full agonist at GluN1/2A (100% response compared with glycine), a partial agonist at GluN1/2B and GluN1/2D (10% and 27%, respectively), and a highly efficacious superagonist at GluN1/2C receptors (353%). Furthermore, AICP potencies are enhanced compared with DCS with EC50 values in the low nanomolar range (1.7 nM at GluN1/2C). We show that GluN1/2C superagonism of AICP and DCS is mediated by overlapping but distinct mechanisms and that AICP selectively enhances responses from recombinant GluN1/2C receptors in the presence of physiological glycine concentrations. This functional selectivity of AICP for GluN2C-containing NMDA receptors is more pronounced compared with DCS, suggesting that AICP can be a useful tool compound for uncovering the roles of GluN2C subunits in neuronal circuit function and in the development of new therapeutic strategies.

An update on the management of sporadic desmoid-type fibromatosis: a European Consensus Initiative between Sarcoma PAtients EuroNet (SPAEN) and European Organization for Research and Treatment of Cancer (EORTC)/Soft Tissue and Bone Sarcoma Group (STBSG).

Desmoid-type fibromatosis is a rare and locally aggressive monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Currently, there is no established or evidence-based treatment approach available for this disease. Therefore, in 2015 the European Desmoid Working Group published a position paper giving recommendations on the treatment of this intriguing disease. Here, we present an update of this consensus approach based on professionals' AND patients' expertise following a round table meeting bringing together sarcoma experts from the European Organization for Research and Treatment of Cancer/Soft Tissue and Bone Sarcoma Group with patients and patient advocates from Sarcoma PAtients EuroNet. In this paper, we focus on new findings regarding the prognostic value of mutational analysis in desmoid-type fibromatosis patients and new systemic treatment options.

Best practices for the management of local-regional recurrent chordoma: a position paper by the Chordoma Global Consensus Group.

Chordomas are rare, malignant bone tumors of the skull-base and axial skeleton. Until recently, there was no consensus among experts regarding appropriate clinical management of chordoma, resulting in inconsistent care and suboptimal outcomes for many patients. To address this shortcoming, the European Society of Medical Oncology (ESMO) and the Chordoma Foundation, the global chordoma patient advocacy group, convened a multi-disciplinary group of chordoma specialists to define by consensus evidence-based best practices for the optimal approach to chordoma. In January 2015, the first recommendations of this group were published, covering the management of primary and metastatic chordomas. Additional evidence and further discussion were needed to develop recommendations about the management of local-regional failures. Thus, ESMO and CF convened a second consensus group meeting in November 2015 to address the treatment of locally relapsed chordoma. This meeting involved over 60 specialists from Europe, the United States and Japan with expertise in treatment of patients with chordoma. The consensus achieved during that meeting is the subject of the present publication and complements the recommendations of the first position paper.

Pazopanib in advanced vascular sarcomas: an EORTC Soft Tissue and Bone Sarcoma Group (STBSG) retrospective analysis.

BACKGROUND: Pazopanib is a multitargeted tyrosine kinase inhibitor approved for the treatment of patients with selective subtypes of advanced soft tissue sarcoma (STS) who have previously received standard chemotherapy including anthracyclines. Data on the efficacy in vascular sarcomas are limited. The main objective of this study was to investigate the activity of pazopanib in vascular sarcomas. PATIENTS AND METHODS: A retrospective study of patients with advanced vascular sarcomas, including angiosarcoma (AS), epithelioid hemangioendothelioma (HE) and intimal sarcoma (IS) treated with pazopanib in real life practice at EORTC centers as well as patients treated within the EORTC phase II and III clinical trials (62043/62072) was performed. Patient and tumor characteristics were collected. Response was assessed according to RECIST 1.1. and survival analysis was performed. RESULTS: Fifty-two patients were identified, 40 (76.9%), 10 (19.2%) and two (3.8%) with AS, HE and IS, respectively. The response rate was eight (20%), two (20%) and two (100%) in the AS, HE and IS subtypes, respectively. There was no significant difference in response rate between cutaneous and non-cutaneous AS and similarly between radiation-associated and non-radiation-associated AS. Median progression-free survival (PFS) and median overall survival (OS; from commencing pazopanib) were three months (95% CI 2.1-4.4) and 9.9 months (95% CI 6.5-11.3) in AS, respectively. CONCLUSION: The activity of pazopanib in AS is comparable to its reported activity in other STS subtypes. In this study, the activity of pazopanib was similar in cutaneous/non-cutaneous and in radiation/non-radiation-associated AS. In addition, pazopanib showed promising activity in HE and IS, worthy of further evaluation.