Mutations in the parkin gene, which encodes a ubiquitin ligase, are a major genetic cause of parkinsonism. Interestingly, parkin also plays a role in cancer as a putative tumor suppressor, and the gene is frequently targeted by deletion and inactivation in human malignant tumors. Here, we investigated a potential tumor suppressor role for parkin in gliomas. We found that parkin expression was dramatically reduced in glioma cells. Restoration of parkin expression promoted G1 phase cell cycle arrest and mitigated the proliferation rate of glioma cells in vitro and in vivo. Notably, parkin-expressing glioma cells showed a reduction in levels of cyclin D1, but not cyclin E, and a selective downregulation of Akt serine-473 phosphorylation and VEGF receptor levels. In accordance, cells derived from a parkin null mouse model exhibited increased levels of cyclin D1, VEGF receptor and Akt phosphorylation and divided significantly faster when compared with wild type cells, with suppressionof these changes following parkin re-introduction. Clinically, analysis of parkin pathway activation was predictive for the survival outcome of glioma patients. Taken together, our study provides mechanistic insight into the tumor suppressor function of parkin in brain tumors, and suggests that measurement of parkin pathway activation may be used clinically as a prognostic tool in brain tumor patients.
Parkin pathway activation mitigates glioma cell proliferation and predicts patient survival.
Cell line, Treatment
View SamplesBrain tumors are among the most malignant cancers and can arise from neural stem cells or oligodendrocyte progenitor cells (OPCs). Glioma-propagating cells (GPCs) that have stem-like properties have been derived from tumor variants such as glioblastoma multiforme (GBM) and oligodendroglial tumors, the latter being more chemosensitive with better prognosis. It has been suggested that such differences in chemosensitivity arise from the different profiles of OPCs versus neural stem cells. We thus explored if GPCs derived from these glioma variants can serve as reliable in vitro culture systems for studies. We utilized gene expression analyses, since GBM and oligodendrogliomas can be molecularly classified. Accordingly, we derived a gene signature distinguishing oligodendroglial GPCs from GBM GPCs collated from different studies, which was enriched for the Wnt, Notch and TGF-beta pathways. Using a novel method in glioma biology, the Connectivity Map, we mapped the strength of gene signature association with patient gene expression profiles in 2 independent glioma databases [GSE16011, http://caintegrator-info.nci.nih.gov/rembrandt]. Our gene signature consistently stratified survival in glioma patients. This data would suggest that in vitro low passage GPCs are similarly driven by transcriptomic changes that characterize the favorable outcome of oligodendrogliomas over GBM. Additionally, the gene signature was associated with the 1p/19q co-deletion status, the current clinical indicator of chemosensitivity. Our gene signature detects molecular heterogeneity in oligodendroglioma patients that cannot be accounted for by histology or the 1p/19q status alone, and highlights the limitation of morphology-based histological analyses in tumor classification, consequently impacting on treatment decisions.
Progenitor-like traits contribute to patient survival and prognosis in oligodendroglial tumors.
Sex, Age, Disease stage, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Master regulators of FGFR2 signalling and breast cancer risk.
Specimen part, Cell line
View SamplesGenome-wide association studies for breast cancer have identified over 80 different risk regions in the genome, with the FGFR2 locus consistently identified as the most strongly associated locus. However, we know little about the mechanisms by which the FGFR2 locus mediates risk or the pathways in which multiple risk loci may combine to cause disease. Here we use a systems biology approach to elucidate the regulatory networks operating in breast cancer and examine the role of FGFR2 in mediating risk. Using model systems we identify FGFR2-regulated genes and, combining variant set enrichment and eQTL analysis, show that these are preferentially linked to breast cancer risk loci. Our results support the concept that cancer-risk associated genes cluster in pathways
Master regulators of FGFR2 signalling and breast cancer risk.
Cell line
View SamplesGenome-wide association studies for breast cancer have identified over 80 different risk regions in the genome, with the FGFR2 locus consistently identified as the most strongly associated locus. However, we know little about the mechanisms by which the FGFR2 locus mediates risk or the pathways in which multiple risk loci may combine to cause disease. Here we use a systems biology approach to elucidate the regulatory networks operating in breast cancer and examine the role of FGFR2 in mediating risk. Using model systems we identify FGFR2-regulated genes and, combining variant set enrichment and eQTL analysis, show that these are preferentially linked to breast cancer risk loci. Our results support the concept that cancer-risk associated genes cluster in pathways
Master regulators of FGFR2 signalling and breast cancer risk.
Cell line
View SamplesGenome-wide association studies for breast cancer have identified over 80 different risk regions in the genome, with the FGFR2 locus consistently identified as the most strongly associated locus. However, we know little about the mechanisms by which the FGFR2 locus mediates risk or the pathways in which multiple risk loci may combine to cause disease. Here we use a systems biology approach to elucidate the regulatory networks operating in breast cancer and examine the role of FGFR2 in mediating risk. Using model systems we identify FGFR2-regulated genes and, combining variant set enrichment and eQTL analysis, show that these are preferentially linked to breast cancer risk loci. Our results support the concept that cancer-risk associated genes cluster in pathways
Master regulators of FGFR2 signalling and breast cancer risk.
Cell line
View SamplesGenome-wide association studies for breast cancer have identified over 80 different risk regions in the genome, with the FGFR2 locus consistently identified as the most strongly associated locus. However, we know little about the mechanisms by which the FGFR2 locus mediates risk or the pathways in which multiple risk loci may combine to cause disease. Here we use a systems biology approach to elucidate the regulatory networks operating in breast cancer and examine the role of FGFR2 in mediating risk. Using model systems we identify FGFR2-regulated genes and, combining variant set enrichment and eQTL analysis, show that these are preferentially linked to breast cancer risk loci. Our results support the concept that cancer-risk associated genes cluster in pathways
Master regulators of FGFR2 signalling and breast cancer risk.
Specimen part
View SamplesSince fibroblasts are a key component of the stroma with an established role in cancer, we investigated the contribution of fibroblasts to the signature observed in the stromal compartment. 13 clonally derived primary stromal fibroblasts were generated from metaplasia, dysplasia and EAC specimens. Expression of a panel of known fibroblast markers and concomitant absence of epithelial markers confirmed their fibroblastic origin. Gene expression profiling of these esophageal fibroblasts demonstrated that three ontologies related to an invasive phenotype (chemotaxis, cell adhesion, regulation of angiogenesis) differentiated cancer associated from BE fibroblasts. Furthermore, the ontologies and KEGG pathways relating to inflammation were all statistically upregulated in the fibroblast signature.
Stromal genes discriminate preinvasive from invasive disease, predict outcome, and highlight inflammatory pathways in digestive cancers.
Sex, Age, Specimen part, Disease
View SamplesWe considered the possibility that removal of E2F4, as a key regulator of cellular quiescence, would cause systemic perturbations in the expression of E2F4 bound genes involved in cell cycle and proliferation. To test whether these pertubrations were reflected in the adult tissues' gene expression programs, we compared the gene expression profile of E2F4 double knockout mice to the gene expression found in identical tissues from E2F4 heterozygous littermates, that are phenotypically normal. We selected liver, testes, and kidney to profile by gene expression analysis, because two of these tissues are affected at some point during development when E2F4 is missing.
Cell cycle genes are the evolutionarily conserved targets of the E2F4 transcription factor.
Sex, Age, Specimen part, Disease, Disease stage, Subject
View SamplesWe used microarrays to further detail a transcriptional signature of TRIM44 by globally assessing genes that have changes in expression upon knockdown on TRIM44 using two independent SiRNAs targetting the gene (in duplicate) and All Stars Negative siRNA (in quadruplicate) as a control
No associated publication
Cell line, Treatment
View Samples