Adenosine A(2A) (A(2A)R) and dopamine D(2) (D(2)R) receptors mediate the antagonism between adenosinergic and dopaminergic transmission in striatopallidal GABAergic neurons and are pharmacological targets for the treatment of Parkinson's disease. Here, a family of heterobivalent ligands containing a D(2)R agonist and an A(2A)R antagonist linked through a spacer of variable size was designed and synthesized to study A(2A)R-D(2)R heteromers. Bivalent ligands with shorter linkers bound to D(2)R or A(2A)R with higher affinity than the corresponding monovalent controls in membranes from brain striatum and from cells coexpressing both receptors. In contrast, no differences in affinity of bivalent versus monovalent ligands were detected in experiments using membranes from cells expressing only one receptor. These findings indicate the existence of A(2A)R-D(2)R heteromers and of a simultaneous interaction of heterobivalent ligands with both receptors. The cooperative effect derived from the simultaneous interaction suggests the occurrence of A(2A)R-D(2)R heteromers in cotransfected cells and in brain striatum. The dopamine/adenosine bivalent action could constitute a novel concept in Parkinson's disease pharmacotherapy.

HB patients GENOMIC STUDY TRANSCRIPTOMIC STUDY METHYLATION STUDY CytoScan HD ®-array RNA-sequencing/ ddPCR HTA ®-array/ RT-qPCR 850K (EPIC)-array/ QUAlu Dysregulation of global RNA & BLCAP editing Overexpression of 14q32 DLK1-DIO3 genes 16 + VIM-gene signature (C1/C2/C2B) 2 epigenomic HB subtypes (Epi-CA & Epi-CB) CLINICAL PARAMETERS: prognostic marker identification Poor prognostic factors:-4q,-18, 17q11.2 AI (NF1) CHKA new therapeutic target Molecular risk stratification MRS1 MRS2 MRS3 Strong 14q32 Epi-CB Time Survival Highlights Hepatoblastoma (HB) involves global dysregulation of RNA editing, including in the tumor suppressor BLCAP. Overexpression of a 300 kb region within the 14q32 DLK1/DIO3 locus is a new hallmark of HB. We identified 2 epigenomic HB subtypes-Epi-CA and Epi-CB-with distinct degrees of DNA hypomethylation and CpG island hypermethylation. The molecular risk stratification of HB, based on the 14q32-signature and epigenomic subtypes, is associated with patient outcomes. The enzyme CHKA could be a novel therapeutic target for patients with HB.

(GABAergic) 2 dynorphinergic neuron, which also expresses substance P (SP), and the GABAergic enkephalinergic neuron (4, 5). In fact, results obtained with in vivo techniques indicate that dopamine exerts differential effects on the two types of GABAergic efferent neurons, by acting on stimulatory D 1 receptors localized in the GABAergic SP-dynorphinergic neurons and inhibitory D 2 receptors localized in the GABAergic enkephalinergic neurons (6 -8). However, functional D 1 -like and D 2 -like receptors, as well as significant levels of D 1 and D 2 receptor mRNA expression, were detected in acutely dissociated striatonigral neurons (9). A more detailed and extensive analysis of the mRNA expression of the different receptor subtypes indicated that there is a limited subset of striatal neurons (ϳ15% of all GABAergic efferent neurons) with a mixed phenotype of GABAergic SP-dynorphinergic and GABAergic enkephalinergic neurons, with D 1 and D 2 receptors (10). This co-expression of D 1 and D 2 receptors has been confirmed in neostriatal neurons at the confocal microscopy level (11,12). George and coworkers (12, 13) have also found evidence for D 1 -D 2 receptor heteromerization (by co-immunoprecipitation) and for the generation of a unique pharmacology of the D 1 -D 2 receptor heteromer, with binding to selective ligands

Despite some caveats, G protein-coupled receptor oligomerization is a phenomenon that is becoming largely accepted. Within these oligomers, however, stoichiometry remains to be elucidated. Here, by using bimolecular fluorescence complementation, we visualized adenosine A 2A receptor homodimers in living cells, showing no apparent difference in the subcellular distribution when compared to the YFP-labelled adenosine A 2A receptor protomer. Interestingly, the combination of bimolecular fluorescence complementation and bioluminescence resonance energy transfer techniques allowed us to detect the occurrence of adenosine A 2A receptors oligomers containing more than two protomers. These results provide new insights into the molecular composition of G protein-coupled receptor oligomers.

Neuroblastoma (NB) is a neoplasm of the sympathetic nervous system, and is the most common solid tumor of infancy. NBs are very heterogeneous, with a clinical course ranging from spontaneous regression to resistance to all current forms of treatment. High-risk patients need intense chemotherapy, and only 30-40% will be cured. Relapsed or metastatic tumors acquire multi-drug resistance, raising the need for alternative treatments. Owing to the diverse mechanisms that are responsible of NB chemoresistance, we aimed to target epigenetic factors that control multiple pathways to bypass therapy resistance. We found that the SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4 (SMARCA4/BRG1) was consistently upregulated in advanced stages of NB, with high BRG1 levels being indicative of poor outcome. Loss-of-function experiments in vitro and in vivo showed that BRG1 is essential for the proliferation of NB cells. Furthermore, whole-genome transcriptome analysis revealed that BRG1 controls the expression of key elements of oncogenic pathways such as PI3K/AKT and BCL2, which offers a promising new combination therapy for high-risk NB.

Lung cancer is one of the most aggressive tumours with very low life expectancy. Altered microRNA expression is found in human tumours because it is involved in tumour growth, progression and metastasis. In this study, we analysed microRNA expression in 47 lung cancer biopsies. Among the most downregulated microRNAs we focussed on the miR-99a characterisation. In vitro experiments showed that miR-99a expression decreases the proliferation of H1650, H1975 and H1299 lung cancer cells causing cell cycle arrest and apoptosis. We identified two novel proteins, E2F2 (E2F transcription factor 2) and EMR2 (EGF-like module-containing, mucin-like, hormone receptor-like 2), downregulated by miR-99a by its direct binding to their 3′-UTR. Moreover, miR-99a expression prevented cancer cell epithelial-to-mesenchymal transition (EMT) and repressed the tumourigenic potential of the cancer stem cell (CSC) population in both these cell lines and mice tumours originated from H1975 cells. The expression of E2F2 and EMR2 at protein level was studied in 119 lung cancer biopsies. E2F2 and EMR2 are preferentially expressed in adenocarcinomas subtypes versus other tumour types (squamous and others). Interestingly, the expression of E2F2 correlates with the presence of vimentin and both E2F2 and EMR2 correlate with the presence of β-catenin. Moreover, miR-99a expression correlates inversely with E2F2 and directly with β-catenin expression in lung cancer biopsies. In conclusion, miR-99a reveals two novel targets E2F2 and EMR2 that play a key role in lung tumourigenesis. By inhibiting E2F2 and EMR2, miR-99a represses in vivo the transition of epithelial cells through an EMT process concomitantly with the inhibition of stemness features and consequently decreasing the CSC population.

Highlights d ATRX IFFs are redistributed genome wide and are enriched at active promoters d The neuronal silencing transcription factor REST is an ATRX IFF target gene d REST and EZH2 silence neuronal gene programs in ATRX IFF NB d REST loss or EZH2 inhibition induces neuronal gene expression programs and NB cell death

Adenosine is a well known neuromodulator in the central nervous system. As a consequence, adenosine can be beneficial in certain disorders and adenosine receptors will be potential targets for therapy in a variety of diseases. Adenosine receptors are G protein-coupled receptors, and are also expressed in a large variety of cells and tissues. Using these receptors as a paradigm of G protein-coupled receptors, the present review focus on how protein-protein interactions might contribute to neurotransmitter/neuromodulator regulation, based on the fact that accessory proteins impinge on the receptor/G protein interaction and therefore modulate receptor functioning. Besides affecting receptor signaling, these accessory components also play a key role in receptor trafficking, internalization and desensitization, as it will be reviewed here. In conclusion, the finding of an increasing number of adenosine receptors interacting proteins, and specially the molecular and functional integration of these accessory proteins into receptorsomes, will open new perspectives in the understanding of particular disorders where these receptors have been proved to be involved.