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Faria C.C.,Arthur and Sonia Labatt Brain Tumour Research Center | Faria C.C.,Centro Hospitalar Lisbon Norte | Golbourn B.J.,Arthur and Sonia Labatt Brain Tumour Research Center | Dubuc A.M.,Arthur and Sonia Labatt Brain Tumour Research Center | And 24 more authors.
Cancer Research | Year: 2015

Medulloblastoma is the most common malignant pediatric brain tumor, with metastases present at diagnosis conferring a poor prognosis. Mechanisms of dissemination are poorly understood and metastatic lesions are genetically divergent from the matched primary tumor. Effective and less toxic therapies that target both compartments have yet to be identified. Here, we report that the analysis of several large non-overlapping cohorts of patients with medulloblastoma reveals MET kinase as a marker of sonic hedgehog (SHH)-driven medulloblastoma. Immunohistochemical analysis of phosphorylated, active MET kinase in an independent patient cohort confirmed its correlation with increased tumor relapse and poor survival, suggesting that patients with SHH medulloblastoma may benefi t fromMET-targeted therapy. In support of this hypothesis, we found that the approved MET inhibitor foretinib could suppress MET activation, decrease tumor cell proliferation, and induce apoptosis in SHH medulloblastomas in vitro and in vivo. Foretinib penetrated the blood-brain barrier and was effective in both the primary and metastatic tumor compartments. In established mouse xenograft or transgenic models of metastatic SHH medulloblastoma, foretinib administration reduced the growth of the primary tumor, decreased the incidence of metastases, and increased host survival. Taken together, our results provide a strong rationale to clinically evaluate foretinib as an effective therapy for patients with SHH-driven medulloblastoma. ©2014 AACR. Source


Wong A.P.,Program in Developmental and Stem Cell Biology | Bear C.E.,Program in Molecular Structure and Function | Chin S.,Program in Molecular Structure and Function | Pasceri P.,Program in Developmental and Stem Cell Biology | And 7 more authors.
Nature Biotechnology | Year: 2012

Cystic fibrosis (CF) is a fatal genetic disease caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene, which regulates chloride and water transport across all epithelia and affects multiple organs, including the lungs. Here we report an in vitro directed differentiation protocol for generating functional CFTR-expressing airway epithelia from human embryonic stem cells. Carefully timed treatment by exogenous growth factors that mimic endoderm developmental pathways in vivo followed by air-liquid interface culture results in maturation of patches of tight junctionĝ€" coupled differentiated airway epithelial cells that demonstrate active CFTR transport function. As a proof of concept, treatment of CF patient induced pluripotent stem cellĝ€"derived epithelial cells with a small-molecule compound to correct for the common CF processing mutation resulted in enhanced plasma membrane localization of mature CFTR protein. Our study provides a method for generating patient-specific airway epithelial cells for disease modeling and in vitro drug testing. © 2012 Nature America, Inc. All rights reserved. Source


Park J.E.,University of British Columbia | Yung R.,University of British Columbia | Stefanowicz D.,University of British Columbia | Shumansky K.,University of British Columbia | And 7 more authors.
Genes and Immunity | Year: 2011

Cystic fibrosis (CF) is one of the most common life-shortening genetic disorders, and the CF transmembrane conductance regulator (CFTR) is the major causal gene. However, a substantial clinical variability among patients with identical CFTR genotypes suggests the presence of modifier genes. We tested the effect of four genes involved in Pseudomonas aeruginosa infection. Analysis of a primary cohort detected eight candidate polymorphisms that were genotyped in the secondary cohort of 1579 patients; lung function and age at first infection with P. aeruginosa were considered as the phenotypes. Both additive and codominant models were considered, adjusting for confounding variables but not for multiple comparisons. In the secondary cohort, heme oxygenase-1 (HMOX1) rs2071749 had the most significant effect on lung function in the pediatric group (P=0.01; P corrected 0.03), and complement factor 3 (C3) rs11569393 and HMOX1 rs2071746 in the adult groups (P=0.03 for both variants; P corrected 0.16, 0.09). No polymorphism of complement factor B (CFB) or toll-like receptor 4 (TLR4) had a significant modifying effect on lung function in either group. We have identified two genes that showed nominal association with disease severity among CF patients. However, because of the multiple comparisons made, further studies are required to confirm the interaction between these modifying genes and CFTR. © 2011 Macmillan Publishers Limited All rights reserved. Source


Masterson C.,University of Toronto | Otulakowski G.,Program in Physiology and Experimental Medicine | Kavanagh B.P.,University of Toronto
Current Opinion in Critical Care | Year: 2015

Purpose of Review: Multiple clinical and laboratory studies have been conducted to illustrate the effects of hypercapnia in a range of injuries, and to understand the mechanisms underlying these effects. The aim of this review is to highlight and interpret information obtained from these recent reports and discuss how they may inform the clinical context. Recent Findings: In the last decade, several important articles have addressed key elements of how carbon dioxide interacts in critical illness states. Among them the most important insights relate to how hypercapnia affects critical illness and include the effects and mechanisms of carbon dioxide in pulmonary hypertension, infection, inflammation, diaphragm dysfunction, and cerebral ischemia. In addition, we discuss molecular insights that apply to multiple aspects of critical illness. Summary: Experiments involving hypercapnia have covered a wide range of illness models with varying degrees of success. It is becoming evident that deliberate hypercapnia in the clinical setting should seldom be used, except wherever necessitated to avoid ventilator-associated lung injury. A more complete understanding of the molecular mechanisms must be established. Copyright © 2015 Wolters Kluwer Health, Inc. Source


Sun L.,University of Toronto | Rommens J.M.,Program in Genetics and Genome Biology | Rommens J.M.,University of Toronto | Corvol H.,French Institute of Health and Medical Research | And 30 more authors.
Nature Genetics | Year: 2012

Variants associated with meconium ileus in cystic fibrosis were identified in 3,763 affected individuals by genome-wide association study (GWAS). Five SNPs at two loci near SLC6A14 at Xq23-24 (minimum P = 1.28 × 10 -12 at rs3788766) and SLC26A9 at 1q32.1 (minimum P = 9.88 × 10 -9 at rs4077468) accounted for ∼5% of phenotypic variability and were replicated in an independent sample of affected individuals (n = 2,372; P = 0.001 and 0.0001, respectively). By incorporating the knowledge that disease-causing mutations in CFTR alter electrolyte and fluid flux across surface epithelium into a hypothesis-driven GWAS (GWAS-HD), we identified associations with the same SNPs in SLC6A14 and SLC26A9 and established evidence for the involvement of SNPs in a third solute carrier gene, SLC9A3. In addition, GWAS-HD provided evidence of association between meconium ileus and multiple genes encoding constituents of the apical plasma membrane where CFTR resides (P = 0.0002; testing of 155 apical membrane genes jointly and in replication, P = 0.022). These findings suggest that modulating activities of apical membrane constituents could complement current therapeutic paradigms for cystic fibrosis. © 2012 Nature America, Inc. All rights reserved. Source

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