Interdependency of EGF and GLP-2 Signaling in Attenuating Mucosal Atrophy in a Mouse Model of Parenteral Nutrition

BACKGROUND & AIMS: Total parenteral nutrition (TPN), a crucial treatment for patients who cannot receive enteral nutrition, is associated with mucosal atrophy, barrier dysfunction, and infectious complications. Glucagon-like peptide-2 (GLP-2) and epidermal growth factor (EGF) improve intestinal epithelial cell (IEC) responses and attenuate mucosal atrophy in several TPN models. However, it remains unclear whether these 2 factors use distinct or overlapping signaling pathways to improve IEC responses. We investigated the interaction of GLP-2 and EGF signaling in a mouse TPN model and in patients deprived of enteral nutrition. METHODS: Adult C57BL/6J, IEC-Egfrknock out (KO) and IEC-pik3r1KO mice receiving TPN or enteral nutrition were treated with EGF or GLP-2 alone or in combination with reciprocal receptor inhibitors, GLP-2(3-33) or gefitinib. Jejunum was collected and mucosal atrophy and IEC responses were assessed by histologic, gene, and protein expression analyses. In patients undergoing planned looped ileostomies, fed and unfed ileum was analyzed. RESULTS: Enteral nutrient deprivation reduced endogenous EGF and GLP-2 signaling in mice and human beings. In the mouse TPN model, exogenous EGF or GLP-2 attenuated mucosal atrophy and restored IEC proliferation. The beneficial effects of EGF and GLP-2 were decreased upon Gefitinib treatment and in TPN-treated IEC-EgfrKO mice, showing epidermal growth factor–receptor dependency for these IEC responses. By contrast, in TPN-treated IEC-pi3kr1KO mice, the beneficial actions of EGF were lost, although GLP-2 still attenuated mucosal atrophy. CONCLUSIONS: Upon enteral nutrient deprivation, exogenous GLP-2 and EGF show strong interdependency for improving IEC responses. Understanding the differential requirements for phosphatidylinositol 3-kinase/phosphoAKT (Ser473) signaling may help improve future therapies to prevent mucosal atrophy

Interdependency of EGF and GLP-2 Signaling in Attenuating Mucosal Atrophy in a Mouse Model of Parenteral Nutrition

Background & Aims: Total parenteral nutrition (TPN), a crucial treatment for patients who cannot receive enteral nutrition, is associated with mucosal atrophy, barrier dysfunction, and infectious complications. Glucagon-like peptide-2 (GLP-2) and epidermal growth factor (EGF) improve intestinal epithelial cell (IEC) responses and attenuate mucosal atrophy in several TPN models. However, it remains unclear whether these 2 factors use distinct or overlapping signaling pathways to improve IEC responses. We investigated the interaction of GLP-2 and EGF signaling in a mouse TPN model and in patients deprived of enteral nutrition. Methods: Adult C57BL/6J, IEC-Egfrknock out (KO) and IEC-pik3r1KO mice receiving TPN or enteral nutrition were treated with EGF or GLP-2 alone or in combination with reciprocal receptor inhibitors, GLP-2(3-33) or gefitinib. Jejunum was collected and mucosal atrophy and IEC responses were assessed by histologic, gene, and protein expression analyses. In patients undergoing planned looped ileostomies, fed and unfed ileum was analyzed. Results: Enteral nutrient deprivation reduced endogenous EGF and GLP-2 signaling in mice and human beings. In the mouse TPN model, exogenous EGF or GLP-2 attenuated mucosal atrophy and restored IEC proliferation. The beneficial effects of EGF and GLP-2 were decreased upon Gefitinib treatment and in TPN-treated IEC-EgfrKO mice, showing epidermal growth factorâreceptor dependency for these IEC responses. By contrast, in TPN-treated IEC-pi3kr1KO mice, the beneficial actions of EGF were lost, although GLP-2 still attenuated mucosal atrophy. Conclusions: Upon enteral nutrient deprivation, exogenous GLP-2 and EGF show strong interdependency for improving IEC responses. Understanding the differential requirements for phosphatidylinositol 3-kinase/phosphoAKT (Ser473) signaling may help improve future therapies to prevent mucosal atrophy. Keywords: Total Parenteral Nutrition, EGF, GLP-2, EGFR, PI3K, Mucosal Atroph

Outcomes of multimodal therapy in a large series of patients with anaplastic thyroid cancer

Background The role of radiotherapy (RT) in the treatment of patients with anaplastic thyroid cancer (ATC) for local tumor control is critical because mortality often is secondary to complications of tumor volume rather than metastatic disease. Herein, the authors report the long-term outcomes of RT for patients with ATC. Methods A total of 104 patients with histologically confirmed ATC were identified who presented to the study institution between 1984 and 2017 and who received curative-intent or postoperative RT. Locoregional progression-free survival (LPFS), overall survival (OS), and distant metastasis-free survival were assessed. Results The median age of the patients was 63.5 years. The median follow-up was 5.9 months (interquartile range, 2.7-17.0 months) for the entire cohort and 10.6 months (interquartile range, 5.3-40.0 months) for surviving patients. Thirty-one patients (29.8%) had metastatic disease prior to the initiation of RT. Concurrent chemoradiation was administered in 99 patients (95.2%) and 53 patients (51.0%) received trimodal therapy. Systemic therapy included doxorubicin (73.7%), paclitaxel with or without pazopanib (24.3%), and other systemic agents (2.0%). The 1-year OS and LPFS rates were 34.4% and 74.4%, respectively. On multivariate analysis, RT >= 60 Gy was associated with improved LPFS (hazard ratio [HR], 0.135; P = .001) and improved OS (HR, 0.487; P = .004), and trimodal therapy was associated with improved LPFS (HR, 0.060; P = .017). The most commonly observed acute grade 3 adverse events included dermatitis (20%) and mucositis (13%), with no grade 4 subacute or late adverse events noted (adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]). Conclusions RT appears to demonstrate a dose-dependent, persistent LPFS and OS benefit in patients with locally advanced ATC with an acceptable toxicity profile. Aggressive RT should be strongly considered for the treatment of patients with ATC as part of a trimodal treatment approach

DHODH modulates transcriptional elongation in the neural crest and melanoma

Melanoma is a tumour of transformed melanocytes, which are originally derived from the embryonic neural crest. It is unknown to what extent the programs that regulate neural crest development interact with mutations in the BRAF oncogene, which is the most commonly mutated gene in human melanoma1. We have used zebrafish embryos to identify the initiating transcriptional events that occur on activation of human BRAF(V600E) (which encodes an amino acid substitution mutant of BRAF) in the neural crest lineage. Zebrafish embryos that are transgenic for mitfa:BRAF(V600E) and lack p53 (also known as tp53) have a gene signature that is enriched for markers of multipotent neural crest cells, and neural crest progenitors from these embryos fail to terminally differentiate. To determine whether these early transcriptional events are important for melanoma pathogenesis, we performed a chemical genetic screen to identify small-molecule suppressors of the neural crest lineage, which were then tested for their effects on melanoma. One class of compound, inhibitors of dihydroorotate dehydrogenase (DHODH), for example leflunomide, led to an almost complete abrogation of neural crest development in zebrafish and to a reduction in the self-renewal of mammalian neural crest stem cells. Leflunomide exerts these effects by inhibiting the transcriptional elongation of genes that are required for neural crest development and melanoma growth. When used alone or in combination with a specific inhibitor of the BRAF(V600E) oncogene, DHODH inhibition led to a marked decrease in melanoma growth both in vitro and in mouse xenograft studies. Taken together, these studies highlight developmental pathways in neural crest cells that have a direct bearing on melanoma formation

Breed-Specific Hematological Phenotypes in the Dog: A Natural Resource for the Genetic Dissection of Hematological Parameters in a Mammalian Species

Remarkably little has been published on hematological phenotypes of the domestic dog, the most polymorphic species on the planet. Information on the signalment and complete blood cell count of all dogs with normal red and white blood cell parameters judged by existing reference intervals was extracted from a veterinary database. Normal hematological profiles were available for 6046 dogs, 5447 of which also had machine platelet concentrations within the reference interval. Seventy-five pure breeds plus a mixed breed control group were represented by 10 or more dogs. All measured parameters except mean corpuscular hemoglobin concentration (MCHC) varied with age. Concentrations of white blood cells (WBCs), neutrophils, monocytes, lymphocytes, eosinophils and platelets, but not red blood cell parameters, all varied with sex. Neutering status had an impact on hemoglobin concentration, mean corpuscular hemoglobin (MCH), MCHC, and concentrations of WBCs, neutrophils, monocytes, lymphocytes and platelets. Principal component analysis of hematological data revealed 37 pure breeds with distinctive phenotypes. Furthermore, all hematological parameters except MCHC showed significant differences between specific individual breeds and the mixed breed group. Twenty-nine breeds had distinctive phenotypes when assessed in this way, of which 19 had already been identified by principal component analysis. Tentative breed-specific reference intervals were generated for breeds with a distinctive phenotype identified by comparative analysis. This study represents the first large-scale analysis of hematological phenotypes in the dog and underlines the important potential of this species in the elucidation of genetic determinants of hematological traits, triangulating phenotype, breed and genetic predisposition

Identification of COUP-TFII Orphan Nuclear Receptor as a Retinoic Acid–Activated Receptor

The chicken ovalbumin upstream promoter-transcription factors (COUP-TFI and II) make up the most conserved subfamily of nuclear receptors that play key roles in angiogenesis, neuronal development, organogenesis, cell fate determination, and metabolic homeostasis. Although the biological functions of COUP-TFs have been studied extensively, little is known of their structural features or aspects of ligand regulation. Here we report the ligand-free 1.48 Å crystal structure of the human COUP-TFII ligand-binding domain. The structure reveals an autorepressed conformation of the receptor, where helix α10 is bent into the ligand-binding pocket and the activation function-2 helix is folded into the cofactor binding site, thus preventing the recruitment of coactivators. In contrast, in multiple cell lines, COUP-TFII exhibits constitutive transcriptional activity, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, and ligand binding, substantially reduce the COUP-TFII transcriptional activity. Importantly, retinoid acids are able to promote COUP-TFII to recruit coactivators and activate a COUP-TF reporter construct. Although the concentration needed is higher than the physiological levels of retinoic acids, these findings demonstrate that COUP-TFII is a ligand-regulated nuclear receptor, in which ligands activate the receptor by releasing it from the autorepressed conformation

A Single cis Element Maintains Repression of the Key Developmental Regulator Gata2

In development, lineage-restricted transcription factors simultaneously promote differentiation while repressing alternative fates. Molecular dissection of this process has been challenging as transcription factor loci are regulated by many trans-acting factors functioning through dispersed cis elements. It is not understood whether these elements function collectively to confer transcriptional regulation, or individually to control specific aspects of activation or repression, such as initiation versus maintenance. Here, we have analyzed cis element regulation of the critical hematopoietic factor Gata2, which is expressed in early precursors and repressed as GATA-1 levels rise during terminal differentiation. We engineered mice lacking a single cis element −1.8 kb upstream of the Gata2 transcriptional start site. Although Gata2 is normally repressed in late-stage erythroblasts, the −1.8 kb mutation unexpectedly resulted in reactivated Gata2 transcription, blocked differentiation, and an aberrant lineage-specific gene expression pattern. Our findings demonstrate that the −1.8 kb site selectively maintains repression, confers a specific histone modification pattern and expels RNA Polymerase II from the locus. These studies reveal how an individual cis element establishes a normal developmental program via regulating specific steps in the mechanism by which a critical transcription factor is repressed

Positron Emission Tomography and Stage Migration in Head and Neck Cancer

IMPORTANCE: Since 2001, there has been a rapid adoption of positron emission tomography (PET) for diagnosis and American Joint Committee on Cancer (AJCC) staging of head and neck cancer (HNC) without data describing improved clinical outcomes. OBJECTIVE: To determine the association between increased use of PET and stage and/or survival for patients with HNC in the managed care environment. DESIGN, SETTING, AND PARTICIPANTS: Adult patients diagnosed as having HNC (n = 958) from 2000 to 2008 at 4 integrated health systems were identified via tumor registries linked to administrative data. The AJCC stage distribution, patient and treatment characteristics, and survival between pre-PET era (2000-2004) vs PET era (2005-2008) and use of PET vs no use of PET during the PET era were compared. The AJCC stages were categorized to represent localized (stage I or II), locally advanced (stage III, IVA, or IVB), and metastatic (stage IVC) disease. INTERVENTIONS: Treatments were determined by billing codes for surgery, radiation treatment, and chemotherapy. MAIN OUTCOMES AND MEASURES: The primary outcome for this study was the use of PET. Secondary outcomes included treatment received and 2-year survival. A logit model estimated the effects of PET on diagnosis of locally advanced disease. Kaplan-Meier estimates described overall survival differences between PET and non-PET. Cox regression evaluated the association of PET on survival in patients with locally advanced disease. RESULTS: An association between PET and locally advanced disease was found (odds ratio, 2.86 [95% CI, 1.90-4.29) (P < .001). Two-year overall survival for patients with locally advanced disease with and without PET was 52% and 32%, respectively (P = .004), but there was no difference for all stages (P = .69). On Cox proportional hazard regression, PET had no association with survival in patients with locally advanced disease (hazard ratio, 1.208 [95% CI, 0.778-1.877]) (P = .40). CONCLUSIONS AND RELEVANCE: The increasing use of PET among patients with HNC is associated with a greater number of patients with higher-stage disease and a dilution of the population with higher-stage disease with patients who have a better prognosis. Thus, the improved survival in patients with locally advanced disease likely reflects selection bias and stage migration. Further research on PET use among patients with HNC is necessary to determine if it results in improved treatment for individual patients

Genome-wide association study identifies peanut allergy-specific loci and evidence of epigenetic mediation in US children

Food allergy (FA) affects 2%-10% of US children and is a growing clinical and public health problem. Here we conduct the first genome-wide association study of well-defined FA, including specific subtypes (peanut, milk and egg) in 2,759 US participants (1,315 children and 1,444 parents) from the Chicago Food Allergy Study, and identify peanut allergy (PA)-specific loci in the HLA-DR and -DQ gene region at 6p21.32, tagged by rs7192 (P=5.5 × 10 -8) and rs9275596 (P=6.8 × 10 -10), in 2,197 participants of European ancestry. We replicate these associations in an independent sample of European ancestry. These associations are further supported by meta-analyses across the discovery and replication samples. Both single-nucleotide polymorphisms (SNPs) are associated with differential DNA methylation levels at multiple CpG sites (