Deficiency in PHD2-mediated hydroxylation of HIF2α underlies Pacak-Zhuang syndrome.

Pacak-Zhuang syndrome is caused by mutations in the EPAS1 gene, which encodes for one of the three hypoxia-inducible factor alpha (HIFα) paralogs HIF2α and is associated with defined but varied phenotypic presentations including neuroendocrine tumors and polycythemia. However, the mechanisms underlying the complex genotype-phenotype correlations remain incompletely understood. Here, we devised a quantitative method for determining the dissociation constant (Kd) of the HIF2α peptides containing disease-associated mutations and the catalytic domain of prolyl-hydroxylase (PHD2) using microscale thermophoresis (MST) and showed that neuroendocrine-associated Class 1 HIF2α mutants have distinctly higher Kd than the exclusively polycythemia-associated Class 2 HIF2α mutants. Based on the co-crystal structure of PHD2/HIF2α peptide complex at 1.8 Å resolution, we showed that the Class 1 mutated residues are localized to the critical interface between HIF2α and PHD2, adjacent to the PHD2 active catalytic site, while Class 2 mutated residues are localized to the more flexible region of HIF2α that makes less contact with PHD2. Concordantly, Class 1 mutations were found to significantly increase HIF2α-mediated transcriptional activation in cellulo compared to Class 2 counterparts. These results reveal a structural mechanism in which the strength of the interaction between HIF2α and PHD2 is at the root of the general genotype-phenotype correlations observed in Pacak-Zhuang syndrome.

Rapid-acting antidepressant drugs modulate affective bias in rats.

How rapid-acting antidepressants (RAADs), such as ketamine, induce immediate and sustained improvements in mood in patients with major depressive disorder (MDD) is poorly understood. A core feature of MDD is the prevalence of cognitive processing biases associated with negative affective states, and the alleviation of negative affective biases may be an index of response to drug treatment. Here, we used an affective bias behavioral test in rats, based on an associative learning task, to investigate the effects of RAADs. To generate an affective bias, animals learned to associate two different digging substrates with a food reward in the presence or absence of an affective state manipulation. A choice between the two reward-associated digging substrates was used to quantify the affective bias generated. Acute treatment with the RAADs ketamine, scopolamine, or psilocybin selectively attenuated a negative affective bias in the affective bias test. Low, but not high, doses of ketamine and psilocybin reversed the valence of the negative affective bias 24 hours after RAAD treatment. Only treatment with psilocybin, but not ketamine or scopolamine, led to a positive affective bias that was dependent on new learning and memory formation. The relearning effects of ketamine were dependent on protein synthesis localized to the rat medial prefrontal cortex and could be modulated by cue reactivation, consistent with experience-dependent neural plasticity. These findings suggest a neuropsychological mechanism that may explain both the acute and sustained effects of RAADs, potentially linking their effects on neural plasticity with affective bias modulation in a rodent model.

Interleukin-11/IL-11 Receptor Promotes Glioblastoma Cell Proliferation, Epithelial-Mesenchymal Transition, and Invasion.

Glioblastoma is highly proliferative and invasive. However, the regulatory cytokine networks that promote glioblastoma cell proliferation and invasion into other areas of the brain are not fully defined. In the present study, we define a critical role for the IL-11/IL-11Rα signalling axis in glioblastoma proliferation, epithelial to mesenchymal transition, and invasion. We identified enhanced IL-11/IL-11Rα expression correlated with reduced overall survival in glioblastoma patients using TCGA datasets. Proteomic analysis of glioblastoma cell lines overexpressing IL-11Rα displayed a proteome that favoured enhanced proliferation and invasion. These cells also displayed greater proliferation and migration, while the knockdown of IL-11Rα reversed these tumourigenic characteristics. In addition, these IL-11Rα overexpressing cells displayed enhanced invasion in transwell invasion assays and in 3D spheroid invasion assays, while knockdown of IL-11Rα resulted in reduced invasion. Furthermore, IL-11Rα-overexpressing cells displayed a more mesenchymal-like phenotype compared to parental cells and expressed greater levels of the mesenchymal marker Vimentin. Overall, our study identified that the IL-11/IL-11Rα pathway promotes glioblastoma cell proliferation, EMT, and invasion.

The Interleukin-11/IL-11 Receptor Promotes Glioblastoma Survival and Invasion under Glucose-Starved Conditions through Enhanced Glutaminolysis.

Glioblastoma cells adapt to changes in glucose availability through metabolic plasticity allowing for cell survival and continued progression in low-glucose concentrations. However, the regulatory cytokine networks that govern the ability to survive in glucose-starved conditions are not fully defined. In the present study, we define a critical role for the IL-11/IL-11Rα signalling axis in glioblastoma survival, proliferation and invasion when cells are starved of glucose. We identified enhanced IL-11/IL-11Rα expression correlated with reduced overall survival in glioblastoma patients. Glioblastoma cell lines over-expressing IL-11Rα displayed greater survival, proliferation, migration and invasion in glucose-free conditions compared to their low-IL-11Rα-expressing counterparts, while knockdown of IL-11Rα reversed these pro-tumorigenic characteristics. In addition, these IL-11Rα-over-expressing cells displayed enhanced glutamine oxidation and glutamate production compared to their low-IL-11Rα-expressing counterparts, while knockdown of IL-11Rα or the pharmacological inhibition of several members of the glutaminolysis pathway resulted in reduced survival (enhanced apoptosis) and reduced migration and invasion. Furthermore, IL-11Rα expression in glioblastoma patient samples correlated with enhanced gene expression of the glutaminolysis pathway genes GLUD1, GSS and c-Myc. Overall, our study identified that the IL-11/IL-11Rα pathway promotes glioblastoma cell survival and enhances cell migration and invasion in environments of glucose starvation via glutaminolysis.

Investigating neuropsychological and reward-related deficits in a chronic corticosterone-induced model of depression.

Chronic stress is a known risk factor for the development of major depression (MDD) and is commonly used to induce a depression-like phenotype in rodents. Similar phenotypic effects are also observed in rodents when treated chronically with the stress hormone corticosterone. In this study, we investigated the neuropsychological consequences of chronic corticosterone treatment in male rats using two translational rodent assays of affective bias, the judgement bias task (JBT) and affective bias test (ABT). We also used the reward learning assay (RLA) and sucrose preference test (SPT) to quantify reward-related behaviours. Negative biases in decision-making were observed in the chronic corticosterone-treated group but only when the treatment was given shortly before each behavioural session. The same dose of corticosterone, when given daily after completion of the behavioural session had no effects. Chronic corticosterone treatment did not potentiate negative affective biases in the ABT induced by either an acute pharmacological or stress manipulation but both reward learning and reward sensitivity were blunted. Analysis of the brain tissue from animals receiving chronic corticosterone found reduced hippocampal neurogenesis consistent with previous studies suggesting corticosterone-induced neurotrophic deficits. Taken together, these data suggest chronic corticosterone treatment induces neuropsychological effects related to changes in reward learning, memory and negative biases in decision making, but these decision-making biases depend on whether rewarding outcomes were experienced during the acute effects of the drug. These findings suggest an important interaction between psychological and biological factors resulting in negative biases in decision-making in this model.

Improved yield of recombinant human IFN-α2b from mammalian cells using heterologous signal peptide approach.

The Type I Interferon cytokine family member, Interferon-α2b (hIFN-α2b), modulates a number of important biological mechanisms including anti-proliferation, immunoregulation and antiviral responses. Due to its role in the immune system, hIFN-α2b has been used as a therapeutic modulator in hepatitis C as well as some forms of leukaemia. Clinical grade hIFN-α2b is typically produced in bacterial expression systems that involves complex refolding protocols and subsequent loss of yields. In this study, we describe an expression and purification system for hIFN-α2b from mammalian cells. Application of the Trypsin-1 signal peptide-propeptide domain significantly improved the expression and secretion of hIFN-α2b from HEK293 cells. We established a simple purification strategy that yields homogenous, pure hIFN-α2b that is stable and biologically active.

How long should clinicians spend sampling the pharynx for gonorrhoea culture specimens?

There are few data on the length of time clinicians should take sampling the pharynx to optimise the sensitivity of gonorrhoea culture specimens and we aimed to gain a consensus on sampling time. The estimated mean time clinicians reported that they spent sampling the pharynx for gonorrhoea culture specimens was 4.63 s (s.d.±2.04). There was no significant difference in sampling times between clinicians who had worked in sexual health for over and under 10 years, (4.7 (s.d.±2.02) vs 4.6 (s.d.±2.3); P =0.45). We are now using these findings to design an educational tool with the aim of improving pharyngeal gonorrhoea culture sensitivity.

D154Q Mutation does not Alter KRAS Dimerization.

KRAS is one of the most frequently mutated oncogenes in human cancers. Despite nearly 40 years of research, KRAS remains largely undruggable, in part due to an incomplete understanding of its biology. Recently, KRAS dimerization was discovered to play an important role in its signalling function. The KRAS D154Q mutant was described as a dimer-deficient variant that can be used to study the effect of dimerization in KRAS oncogenicity. However, we show here that KRAS D154Q homo- and heterodimerized with KRAS WT using three separate protein-protein interaction assays, and that oncogenic KRAS dimerization was not negatively impacted by the presence of a secondary D154Q mutation. In conclusion, we advise caution in using this variant to study the purpose of dimerization in KRAS oncogenic behaviour.

Interviewing anorexia: How do individuals given a diagnosis of anorexia nervosa experience Voice Dialogue with their eating disorder voice? A qualitative analysis.

A proportion of individuals given an eating disorder diagnosis describe the experience of an eating disorder 'voice' (EDV). However, methods for working with this experience are currently lacking. Voice Dialogue (Stone & Stone, 1989) involves direct communication between a facilitator and parts of the self to increase awareness, understanding, and separation from inner voices. Adapted forms of this method have shown promise in working with voices in psychosis. This study aimed to explore the experience and acceptability of Voice Dialogue amongst individuals with anorexia nervosa who experience an EDV. Nine women participated in a semistructured interview following a single Voice Dialogue session. Interview transcripts were analysed using interpretative phenomenological analysis (IPA). Three overarching themes were identified as follows: (i) "separating from the EDV"; (ii) "better understanding of the EDV"; and (iii) "hopeful, motivated, and afraid of recovery". The majority of participants found Voice Dialogue acceptable and helpful for exploring their EDV. Whilst preliminary, the results suggest that Voice Dialogue has potential in terms of helping individuals establish a more constructive relationship with their EDV and motivating change. Further research is needed to build upon these findings. Implications for addressing the EDV using voice-focused interventions are explored.

HIF-1α Hydroxyprolines Modulate Oxygen-Dependent Protein Stability Via Single VHL Interface With Comparable Effect on Ubiquitination Rate.

The basic molecular mechanism underlying mammalian oxygen-dependent regulation of hypoxia-inducible factor (HIF) via the von Hippel-Lindau E3 ubiquitin ligase is well established. The principal step in this critical cellular process is the hydroxylation of either or both of the two conserved proline residues P402 and P564 within the oxygen-dependent degradation domain (ODD) of HIF-1α subunit via prolyl hydroxylases, which is necessary for binding VHL. However, the significance of the two prolines has remained unclear considering that only one hydroxyproline is sufficient for the recruitment of VHL. Here, we show using biophysical analyses that both hydroxyprolines bind to the same interface on VHL with similar affinity; VHL binding affinity to HIF-1α ODD remains relatively unchanged regardless of whether the ODD contains one or two hydroxyprolines; ODD with two hydroxyprolines can accommodate two VHLs; and the rate of in vitro ubiquitination of ODD with one hydroxyproline via VHL E3 ligase is comparable to the rate observed with ODD containing two hydroxyprolines. However, the two hydroxyprolines show distinct contributions to the intracellular stability of HIF-1α ODD. These results demonstrate for the first time that the graduated HIF-1α stability profile observed over a range of oxygen tension is not attributed to the binding of or ubiquitination via VHL per se, but is likely due to the preceding events such as the efficacy of oxygen-dependent prolyl hydroxylase-mediated hydroxylation of HIF-1α.

Carfilzomib Promotes the Unfolded Protein Response and Apoptosis in Cetuximab-Resistant Colorectal Cancer.

Cetuximab is a common treatment option for patients with wild-type K-Ras colorectal carcinoma. However, patients often display intrinsic resistance or acquire resistance to cetuximab following treatment. Here we generate two human CRC cells with acquired resistance to cetuximab that are derived from cetuximab-sensitive parental cell lines. These cetuximab-resistant cells display greater in vitro proliferation, colony formation and migration, and in vivo tumour growth compared with their parental counterparts. To evaluate potential alternative therapeutics to cetuximab-acquired-resistant cells, we tested the efficacy of 38 current FDA-approved agents against our cetuximab-acquired-resistant clones. We identified carfilzomib, a selective proteosome inhibitor to be most effective against our cell lines. Carfilzomib displayed potent antiproliferative effects, induced the unfolded protein response as determined by enhanced CHOP expression and ATF6 activity, and enhanced apoptosis as determined by enhanced caspase-3/7 activity. Overall, our results indicate a potentially novel indication for carfilzomib: that of a potential alternative agent to treat cetuximab-resistant colorectal cancer.

EGFRvIII Promotes Cell Survival during Endoplasmic Reticulum Stress through a Reticulocalbin 1-Dependent Mechanism.

Reticulocalbin 1 (RCN1) is an endoplasmic reticulum (ER)-residing protein, involved in promoting cell survival during pathophysiological conditions that lead to ER stress. However, the key upstream receptor tyrosine kinase that regulates RCN1 expression and its potential role in cell survival in the glioblastoma setting have not been determined. Here, we demonstrate that RCN1 expression significantly correlates with poor glioblastoma patient survival. We also demonstrate that glioblastoma cells with expression of EGFRvIII receptor also have high RCN1 expression. Over-expression of wildtype EGFR also correlated with high RCN1 expression, suggesting that EGFR and EGFRvIII regulate RCN1 expression. Importantly, cells that expressed EGFRvIII and subsequently showed high RCN1 expression displayed greater cell viability under ER stress compared to EGFRvIII negative glioblastoma cells. Consistently, we also demonstrated that RCN1 knockdown reduced cell viability and exogenous introduction of RCN1 enhanced cell viability following induction of ER stress. Mechanistically, we demonstrate that the EGFRvIII-RCN1-driven increase in cell survival is due to the inactivation of the ER stress markers ATF4 and ATF6, maintained expression of the anti-apoptotic protein Bcl-2 and reduced activity of caspase 3/7. Our current findings identify that EGFRvIII regulates RCN1 expression and that this novel association promotes cell survival in glioblastoma cells during ER stress.

A comprehensive characterization of the cell-free transcriptome reveals tissue- and subtype-specific biomarkers for cancer detection.

Cell-free RNA (cfRNA) is a promising analyte for cancer detection. However, a comprehensive assessment of cfRNA in individuals with and without cancer has not been conducted. We perform the first transcriptome-wide characterization of cfRNA in cancer (stage III breast [n = 46], lung [n = 30]) and non-cancer (n = 89) participants from the Circulating Cell-free Genome Atlas (NCT02889978). Of 57,820 annotated genes, 39,564 (68%) are not detected in cfRNA from non-cancer individuals. Within these low-noise regions, we identify tissue- and cancer-specific genes, defined as "dark channel biomarker" (DCB) genes, that are recurrently detected in individuals with cancer. DCB levels in plasma correlate with tumor shedding rate and RNA expression in matched tissue, suggesting that DCBs with high expression in tumor tissue could enhance cancer detection in patients with low levels of circulating tumor DNA. Overall, cfRNA provides a unique opportunity to detect cancer, predict the tumor tissue of origin, and determine the cancer subtype.

Reduced EGFR and increased miR-221 is associated with increased resistance to temozolomide and radiotherapy in glioblastoma.

Despite aggressive treatment with temozolomide and radiotherapy and extensive research into alternative therapies there has been little improvement in Glioblastoma patient survival. Median survival time remains between 12 and 15 months mainly due to treatment resistance and tumor recurrence. In this study, we aimed to explore the underlying mechanisms behind treatment resistance and the lack of success with anti-EGFR therapy in the clinic. After generating a number of treatment resistant Glioblastoma cell lines we observed that resistant cell lines lacked EGFR activation and expression. Furthermore, cell viability assays showed resistant cells were significantly less sensitive to the anti-EGFR agents when compared to parental cell lines. To further characterise the resistance mechanism in our cells microRNA prediction software identified miR-221 as a negative regulator of EGFR expression. miR-221 was up-regulated in our resistant cell lines, and this up-regulation led to a significant reduction in EGFR expression in both our cultured cell lines and a large cohort of glioblastoma patient tumor tissue.

Evidence that neuropsychological deficits following early life adversity may underlie vulnerability to depression.

Early life adversity (ELA) is a risk factor for major depressive disorder (MDD), however the underlying mechanisms are not well understood. Clinical studies suggest that negative affective biases (the process, whereby cognitive processes such as learning and memory and decision-making are modified by emotional state) represent a vulnerability factor for MDD. In this study we investigate the impact of ELA on affective biases and reward-associated behaviours in rats. Sprague Dawley rat pups underwent 14 days of postnatal maternal separation (180 min/day from postnatal day 1: MS180) whilst control pups remained unhandled. In adulthood, affective biases associated with reward learning and decision-making were assessed using the affective bias test (ABT), or judgement bias task (JBT) respectively. Changes in motivation and reward sensitivity were tested in a progressive ratio (PR) schedule of operant responding and the sucrose preference test (SPT) respectively. We observed that MS180 animals expressed enhanced negative biases in response to acute corticosterone treatment but without effects on antidepressant-induced positive biases. ELA animals were impaired in their ability to develop appropriate biases in response to changes in reward value in a modified ABT but in the absence of any changes in reward sensitivity or motivation. No effects on decision-making were observed in the JBT but MS180 animals failed to develop the same more optimistic behavioural profile as controls in response to an increase in reward value. These findings suggest that ELA in rats increases vulnerability to negative affective biases and impairs animals' ability to appropriately learn reward value, independent of a reward sensitivity or changes in motivation. These data provide important evidence linking ELA with relevant neuropsychological impairments that may explain increased risk of developing MDD.

Listeria monocytogenes and Shigella flexneri Activate the NLRP1B Inflammasome.

Activation of the innate immune receptor NLRP1B leads to the formation of an inflammasome, which induces autoproteolytic processing of pro-caspase-1, and ultimately to the release of inflammatory cytokines and to the execution of pyroptosis. One of the signals to which NLRP1B responds is metabolic stress that occurs in cells deprived of glucose or treated with metabolic inhibitors. NLRP1B might therefore sense microbial infection, as intracellular pathogens such as Listeria monocytogenes and Shigella flexneri cause metabolic stress as a result of nutrient scavenging and host cell damage. Here we addressed whether these pathogens activate the NLRP1B inflammasome. We found that Listeria infection activated the NLRP1B inflammasome in a reconstituted fibroblast model. Activation of NLRP1B by Listeria was diminished in an NLRP1B mutant shown previously to be defective at detecting energy stress and was dependent on the expression of listeriolysin O (LLO), a protein required for vacuolar escape. Infections of either Listeria or Shigella activated NLRP1B in the RAW264.7 murine macrophage line, which expresses endogenous NLRP1B. We conclude that NLRP1B senses cellular infection by distinct invasive pathogens.

Further validation of the affective bias test for predicting antidepressant and pro-depressant risk: effects of pharmacological and social manipulations in male and female rats.

RATIONALE: Affective biases are hypothesised to contribute to the cause and treatment of mood disorders. We have previously found that affective biases, associated with learning and memory, are observed following acute treatments with a range of antidepressant and pro-depressant manipulations. OBJECTIVE: This study aimed to test if similar biases are observed in male and female Sprague Dawley (SD) rats. We also test whether the stress hormone, corticosterone, induces a negative bias in the affective bias test (ABT) consistent with its putative role in the development of depression. We then use a meta-analysis to compare our findings with data published for the Lister Hooded rats. METHODS: The ABT uses a within-subject study design where animals learn to associate distinct digging substrates, encountered on different days, with the same value food reward. Exposure to one substrate is paired with a treatment manipulation (drug or environmental) and the other with a control condition. A preference test is used to test if the treatment has induced a positive or negative bias. RESULTS: Consistent with previous data, both male and female SD rats exhibit similar positive affective biases following treatment with the antidepressant, venlafaxine, and social play and negative affective biases following FG 7142 (benzodiazepine inverse agonist) and social stress. Acute treatment with corticosterone induced a negative bias. CONCLUSIONS: These data add to the translational validity of the ABT and suggest that corticosterone can induce a negative affective bias following acute treatment, an effect which may contribute to its long-term effects on mood.

Tumor recurrence of keratinocyte carcinomas judged appropriate for Mohs micrographic surgery using Appropriate Use Criteria.

BACKGROUND: The use of Mohs micrographic surgery (MMS) has increased greatly to treat basal cell and cutaneous squamous cell carcinomas (keratinocyte carcinoma [KC]), and consensus-based Appropriate Use Criteria (AUC) were developed to identify tumors for which MMS is appropriate. OBJECTIVE: We sought to compare recurrence rates after different treatments in tumors judged appropriate for MMS. METHODS: We used data from an observational prospective cohort study and retrospectively categorized consecutive tumors as appropriate for MMS according to the AUC. Among appropriate tumors, we used survival analyses to compare 5-year recurrence rates after treatments. RESULTS: Among tumors appropriate for MMS (N = 1483), adjusted 5-year recurrence rates were 2.9% (range, 1.4-4.3%) after MMS, 5.5% (range, 3.1-7.9%) after excision, 4.0% (range, 0.6-7.2%) after destruction, and 5.9% (range, 1.5-10.2%) after other treatments. In tumors treated only with MMS or excision (the most similar subgroups), the adjusted hazard ratio of 5-year recurrence after MMS was 0.6 (95% confidence interval, 0.3-1.0; P = .06). LIMITATIONS: This study is limited by its uncertain generalizability, lack of randomization, and unmeasured characteristics. CONCLUSION: The AUC identified tumors for which recurrence would be less common after MMS than after excision, but the absolute difference in recurrence rates was small.