Search

Glioblastoma (GBM) is a universally fatal brain cancer, for which novel therapies targeting specific underlying oncogenic events are urgently needed. While the WNT pathway has been shown to be frequently activated in GBM, constituting a potential therapeutic target, the relevance of WNT6, an activator of this pathway, remains unknown. Methods: WNT6 protein and mRNA levels were evaluated in GBM. WNT6 levels were silenced or overexpressed in GBM cells to assess functional effects in vitro and in vivo . Phospho-kinase arrays and TCF/LEF reporter assays were used to identify WNT6-signaling pathways, and significant associations with stem cell features and cancer-related pathways were validated in patients. Survival analyses were performed with Cox regression and Log-rank tests. Meta-analyses were used to calculate the estimated pooled effect. Results: We show that WNT6 is significantly overexpressed in GBMs, as compared to lower-grade gliomas and normal brain, at mRNA and protein levels. Functionally, WNT6 increases typical oncogenic activities in GBM cells, including viability, proliferation, glioma stem cell capacity, invasion, migration, and resistance to temozolomide chemotherapy. Concordantly, in in vivo orthotopic GBM mice models, using both overexpressing and silencing models, WNT6 expression was associated with shorter overall survival, and increased features of tumor aggressiveness. Mechanistically, WNT6 contributes to activate typical oncogenic pathways, including Src and STAT, which intertwined with the WNT pathway may be critical effectors of WNT6-associated aggressiveness in GBM. Clinically, we establish WNT6 as an independent prognostic biomarker of shorter survival in GBM patients from several independent cohorts. Conclusion: Our findings establish WNT6 as a novel oncogene in GBM, opening opportunities to develop more rational therapies to treat this highly aggressive tumor., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Transition zones are of high evolutionary interest because unique patterns of spatial variation are often retained. Here, we investigated the phylogeography of the peacock blenny, Salaria pavo , a small marine intertidal fish that inhabits rocky habitats of the Mediterranean and the adjacent Atlantic Ocean. We screened 170 individuals using mitochondrial and nuclear sequence data from eight locations. Four models of genetic structure were tested: panmixia, isolation-by-distance, secondary contact and phylogeographic break. Results indicated clear asymmetric migration from the Mediterranean to the Atlantic but only marginally supported the isolation-by-distance model. Additionally, the species displays an imprint of demographic expansion compatible with the last glacial maximum. Although the existence of a refugium in the Mediterranean cannot be discarded, the ancestral lineage most likely originated in the Atlantic, where most of the genetic diversity occurs., Competing Interests: Rita Castilho is an Academic Editor for PeerJ.

Introduction: Despite being the second most frequent tumor in children, pediatric central nervous system (CNS) tumors are rare, and the published European epidemiological data is limited. Our goal is to present the first surgical series of pediatric CNS tumors in Portugal and to review other similar worldwide series., Methods: Retrospective review of all patients younger than 19 years old, operated to a CNS tumor in the Neurosurgery Department at Hospital de Santa Maria (Lisbon, Portugal) between January 2004 and December 2014. Demographic data, tumor location, clinical data, histopathology, and surgical treatment were analyzed and compared to surgical series of pediatric CNS tumors published in PubMed indexed journals over the last 20 years., Results: We performed 253 surgeries in 215 patients, with a male:female ratio of 1.2:1 and a mean age of 9.2 years old. Primary brain tumors accounted for 95 % of all tumors and had more often a supratentorial location. Tumors of neuroepithelial tissue, particularly astrocytic tumors, embryonal tumors, neuronal and mixed neuronal-glial tumors, and oligodendrogliomas accounted for 81 % of cases. A gross-total resection was achieved in most cases. There was no mortality, and the overall morbidity was low., Conclusions: The demography, topography, and clinical presentation of the tumors and the surgical results of this series are comparable to other European ones. We found a higher incidence of neuronal and mixed neuronal-glial tumors and oligodendrogliomas and a slight lower incidence of ependymomas. Our results should encourage further national multi-institutional studies to better characterize these tumors in the pediatric population.

Background/aim: Healthy individuals present variable responses of the hypothalamic-pituitary-adrenal (HPA) axis induced by different patterns of physical training. The aim of this study was to evaluate whether prolonged low-grade physical training influences the HPA axis and also glucocorticoid receptor-alpha (GRalpha) mRNA levels in mononuclear cells of obese adolescents., Methods: We studied 19 patients with BMI above the 95th percentile (male:female ratio 7:12) aged from 9.5 to 15.5 years. Patients underwent a 12-week physical exercise program. Before and after exercise, in vivo glucocorticoid sensitivity was determined by employing a very-low-dose intravenous dexamethasone suppression test, and in vitro GRalpha mRNA levels were evaluated by quantitative real-time PCR., Results: After exercise there was a trend to reduce the in vivo glucocorticoid sensitivity (p = 0.071) and a significant increase in GRalpha mRNA levels (p = 0.025)., Conclusion: For this subset of obese adolescents, prolonged low-grade physical training tended to reduce glucocorticoid sensitivity. The discrepancy of cortisol response to dexamethasone and the GRalpha mRNA measurement suggest a post-receptor phenomenon or should be related to target tissue-specific differences in glucocorticoid sensitivity. Future studies should address the adaptive GRalpha mRNA during different exercise protocols, and also the correlation of pituitary sensitivity with glucocorticoid target tissue sensitivity., (Copyright 2010 S. Karger AG, Basel.)

Glucocorticoids play an essential role in maintaining basal and stress-related homeostasis. Most known effects of glucocorticoids are mediated by the intracellular glucocorticoid receptors. The glucocorticoid sensitivity seems to depend on the amount of receptors expressed and the efficiency of glucocorticoid receptor-mediated signal transduction. Glucocorticoid resistance or hypersensitivity, seen in autoimmune-inflammatory diseases and in metabolic syndrome respectively, can represent the variability of several steps that influence the signaling cascade of glucocorticoid action. The recognition of these steps could provide the understanding of the clinical phenotype and course of such diseases as well as their responsiveness to glucocorticoid therapy. The comprehension of these pathophysiological mechanisms can also improve the possible therapeutic interventions. In this review, we have summarized the multiple factors that have been shown to be involved in this signaling cascade and, thus, to influence glucocorticoid sensitivity.