BET protein inhibition sensitizes glioblastoma cells to temozolomide treatment by attenuating MGMT expression

Bromodomain and extra-terminal tail (BET) proteins have been identified as potential epigenetic targets in cancer, including glioblastoma. These epigenetic modifiers link the histone code to gene transcription that can be disrupted with small molecule BET inhibitors (BETi). With the aim of developing rational combination treatments for glioblastoma, we analyzed BETi-induced differential gene expression in glioblastoma derived-spheres, and identified 6 distinct response patterns. To uncover emerging actionable vulnerabilities that can be targeted with a second drug, we extracted the 169 significantly disturbed DNA Damage Response genes and inspected their response pattern. The most prominent candidate with consistent downregulation, was the O-6-methylguanine-DNA methyltransferase (MGMT) gene, a known resistance factor for alkylating agent therapy in glioblastoma. BETi not only reduced MGMT expression in GBM cells, but also inhibited its induction, typically observed upon temozolomide treatment. To determine the potential clinical relevance, we evaluated the specificity of the effect on MGMT expression and MGMT mediated treatment resistance to temozolomide. BETi-mediated attenuation of MGMT expression was associated with reduction of BRD4- and Pol II-binding at the MGMT promoter. On the functional level, we demonstrated that ectopic expression of MGMT under an unrelated promoter was not affected by BETi, while under the same conditions, pharmacologic inhibition of MGMT restored the sensitivity to temozolomide, reflected in an increased level of γ-H2AX, a proxy for DNA double-strand breaks. Importantly, expression of MSH6 and MSH2, which are required for sensitivity to unrepaired O6-methylguanine-lesions, was only briefly affected by BETi. Taken together, the addition of BET-inhibitors to the current standard of care, comprising temozolomide treatment, may sensitize the 50% of patients whose glioblastoma exert an unmethylated MGMT promoter

Efficient Delivery of MicroRNA and AntimiRNA Molecules Using an Argininocalix[4]arene Macrocycle

MicroRNAs (miRNAs) are short non-coding RNA molecules acting as gene regulators by repressing translation or by inducing degradation of the target RNA transcripts. Altered expression of miRNAs may be involved in the pathogenesis of many severe human diseases, opening new avenues in the field of therapeutic strategies, i.e., miRNA targeting or miRNA mimicking. In this context, the efficient and non-toxic delivery of premiRNA and antimiRNA molecules might be of great interest. The aim of the present paper is to determine whether an argininocalix[4]arene is able to efficiently deliver miRNA, premiRNA, and antimiRNA molecules to target cells, preserving their biological activity. This study points out that (1) the toxicity of argininocalix[4]arene 1 is low, and it can be proposed for long-term treatment of target cells, being that this feature is a pre-requisite for the development of therapeutic protocols; (2) the delivery of premiRNA and antimiRNA molecules is efficient, being higher when compared with reference gold standards available; and (3) the biological activity of the premiRNAs and antimiRNAs is maintained. This was demonstrated using the argininocalix[4]arene 1 in miRNA therapeutic approaches performed on three well-described experimental model systems: (1) the induction of apoptosis by antimiR-221 in glioma U251 cells; (2) the induction of apoptosis by premiR-124 in U251 cells; and (3) the inhibition of pro-inflammatory IL-8 and IL-6 genes in cystic fibrosis IB3-1 cells. Our results demonstrate that the argininocalix[4]arene 1 should be considered a very useful delivery system for efficient transfer to target cells of both premiRNA and antimiRNA molecules, preserving their biological activity

A global charter for the public\u27s health - The public\u27s health: the role, functions, competencies, education

Political leaders increasingly perceive health as being crucial to achieving growth, development, equity and stability throughout the world. Health is now understood as a product of complex and dynamic relations generated by numerous determinants at different levels of governance. Governments need to take into account the impact of social, environmental and behavioural health determinants, including economic constraints, living conditions, demographic changes and unhealthy lifestyles in many of the World Health Organization (WHO) Member States. This understanding and increasing globalization means it is very timely to review the role of (global) public health in this changing societal and political environment

Custom Made Candy Plug for Distal False Lumen Occlusion in Aortic Dissection: International Experience

Objective: To evaluate early and midterm outcomes of the Candy Plug (CP) technique for distal false lumen (FL) occlusion in thoracic endovascular aortic repair for aortic dissection (AD) in a more real world cohort of patients from an international multicentre registry. Methods: A multicentre retrospective study was conducted of all consecutive patients from the contributing centres with subacute and chronic AD treated with the CP technique from October 2013 to April 2020 at 18 centres. Results: A custom made CP was used in 155 patients (92 males, mean age 62 ± 11 years). Fourteen (9%) presented with ruptured false lumen aneurysms. Technical success was achieved in all patients (100%). Clinical success was achieved in 138 patients (89%). The median hospital stay was 7 days (1 – 77). The 30 day mortality rate was 3% (n = 5). Stroke occurred in four patients (3%). Spinal cord ischaemia occurred in three patients (2%). The 30 day computed tomography angiogram (CTA) confirmed successful CP placement at the intended level in all patients. Early complete FL occlusion was achieved in 120 patients (77%). Early (30 day) CP related re-intervention was required in four patients (3%). The early (30 day) stent graft related re-intervention rate was 8% (n = 12). Follow up CTA was available in 142 patients (92%), with a median follow up of 23 months (6 – 87). Aneurysmal regression was achieved in 68 of 142 patients (47%); the aneurysm diameter remained stable in 69 of 142 patients (49%) and increased in five of 142 patients (4%). A higher rate of early FL occlusion was detected in the largest volume centre patients (50 [88%] vs. 70 [71%] from other centres; p = .019). No other differences in outcome were identified regarding volume of cases or learning curve. Conclusion: This international CP technique experience confirmed its feasibility and low mortality and morbidity rates. Aortic remodelling and false lumen thrombosis rates were high and support the concept of distal FL occlusion in AD using the CP technique

Sleep-Deprivation Regulates α-2 Adrenergic Responses of Rat Hypocretin/Orexin Neurons

We recently demonstrated, in rat brain slices, that the usual excitation by noradrenaline (NA) of hypocretin/orexin (hcrt/orx) neurons was changed to an inhibition following sleep deprivation (SD). Here we describe that in control condition (CC), i.e. following 2 hours of natural sleep in the morning, the α2-adrenergic receptor (α2-AR) agonist, clonidine, had no effect on hcrt/orx neurons, whereas following 2 hours of SD (SDC), it hyperpolarized the neurons by activating G-protein-gated inwardly rectifying potassium (GIRK) channels. Since concentrations of clonidine up to a thousand times (100 µM) higher than those effective in SDC (100 nM), were completely ineffective in CC, a change in the availability of G-proteins is unlikely to explain the difference between the two conditions. To test whether the absence of effect of clonidine in CC could be due to a down-regulation of GIRK channels, we applied baclofen, a GABAB agonist known to also activate GIRK channels, and found that it hyperpolarized hcrt/orx neurons in that condition. Moreover, baclofen occluded the response to clonidine in SDC, indicating that absence of effect of clonidine in CC could not be attributed to down-regulation of GIRK channels. We finally tested whether α2-ARs were still available at the membrane in CC and found that clonidine could reduce calcium currents, indicating that α2-ARs associated with calcium channels remain available in that condition. Taken together, these results suggest that a pool of α2-ARs associated with GIRK channels is normally down-regulated (or desensitized) in hcrt/orx neurons to only become available for their inhibition following sleep deprivation