MacK S.C.,Hospital for Sick Children |
MacK S.C.,University of Toronto |
MacK S.C.,101 College St |
Witt H.,German Cancer Research Center |
And 16 more authors.
Brain Pathology | Year: 2013
Ependymoma is the third most common pediatric brain tumor, yet because of the paucity of effective therapeutic interventions, 45% of patients remain incurable. Recent transcriptional and copy number profiling of the disease has identified few driver genes and in fact points to a balanced genomic profile. Candidate gene approaches looking at hypermethylated promoters and genome-wide epigenetic arrays suggest that DNA methylation may be critical to ependymoma pathogenesis. This review attempts to highlight existing and emerging evidence implicating the ependymoma epigenome as a key player and that epigenetic modifiers may offer new targeted therapeutic avenues for patients. © 2013 International Society of Neuropathology.
Milstone D.S.,Vascular Research Division |
Ilyama M.,Toronto General Research Institute |
Ilyama M.,University of Toronto |
Ilyama M.,Kyoto University |
And 22 more authors.
Circulation Research | Year: 2015
Rationale: Human and murine Vcam1 promoters contain 2 adjacent nuclear factor-κB (NF-κB)-binding elements. Both are essential for cytokine-induced transcription of transiently transfected promoter-reporter constructs. However, the relevance of these insights to regulation of the endogenous Vcam1 gene and to pathophysiological processes in vivo remained unknown. Objective: Determine the role of the 5′ NF-κB-binding element in expression of the endogenous Vcam1 gene. Methods and Results: Homologous recombination in embryonic stem cells was used to inactivate the 5′ NF-κB element in the Vcam1 promoter and alter 3 nucleotides in the 5′ untranslated region to allow direct comparison of wild-type versus mutant allele RNA expression and chromatin configuration in heterozygous mice. Systemic treatment with inflammatory cytokines or endotoxin (lipopolysaccharide) induced lower expression of the mutant allele relative to wild-type by endothelial cells in the aorta, heart, and lungs. The mutant allele also showed lower endothelial expression in 2-week atherosclerotic lesions in Vcam1 heterozygous/low-density lipoprotein receptor-deficient mice fed a cholesterol-rich diet. In vivo chromatin immunoprecipitation assays of heart showed diminished lipopolysaccharide-induced association of RNA polymerase 2 and NF-κB p65 with the mutant promoter. In contrast, expression of mutant and wild-type alleles was comparable in intimal cells of wire-injured carotid artery and 4- to 12-week atherosclerotic lesions. Conclusions: This study highlights differences between in vivo and in vitro promoter analyses, and reveals a differential role for a NF-κB transcriptional response element in endothelial vascular cell adhesion molecule-1 expression induced by inflammatory cytokines or a cholesterol-rich diet versus intimal cell expression in atherosclerotic lesions and injured arteries. © 2015 American Heart Association, Inc.