The main cell of origin of the Sonic hedgehog (SHH) subgroup of medulloblastoma (MB) is granule cell precursors (GCPs), a SHH-dependent transient amplifying population in the developing cerebellum. SHH-MBs can be further subdivided based on molecular and clinical parameters, as well as location since SHH-MBs occur preferentially in the lateral cerebellum (hemispheres). Our analysis of adult patient data suggests that tumors with Smoothened (SMO) mutations form more specifically in the hemispheres than those with Patched 1 (PTCH1) mutations. Using sporadic mouse models of SHH-MB with the two mutations commonly seen in adult MB, constitutive activation of Smo (SmoM2) or loss-of-Ptch1, we found that regardless of timing of induction or type of mutation, tumors developed primarily in the hemispheres with SmoM2-mutants indeed showing a stronger specificity. We further uncovered that GCPs in the hemispheres are more susceptible to high level SHH signaling compared to GCPs in the medial cerebellum (vermis), as more SmoM2 or Ptch1-mutant hemisphere cells remain undifferentiated and show increased tumorigenicity when transplanted. Finally, we identified location-specific GCP gene expression profiles, and found that deletion of the genes most highly expressed in the hemispheres (Nr2f2) or vermis (Engrailed1) showed opposing effects on GCP differentiation. Our studies thus provide new insights into intrinsic differences within GCPs that impact on SHH-MB progression.
Lateral cerebellum is preferentially sensitive to high sonic hedgehog signaling and medulloblastoma formation.
Specimen part
View SamplesFVB mice were engineered to express wild-type human cyclin E under control of the human surfactant C promoter (CEO mice; Ma et al, PNAS 2007). These mice develop spontaneous lung tumors, which were shown to be adenocarcinoma by histological analysis. Here we compare whole-genome RNA expression levels between the tumors and normal lung of 4 CEO mice as well as 4 nontransgenic animals.
Evidence for tankyrases as antineoplastic targets in lung cancer.
Sex, Specimen part
View SamplesMitochondrial dysfunction has been directly or indirectly implicated in the pathogenesis of a number of neurodegenerative disorders including Parkinson's disease, Alzheimer's disease and Amyotrophic Lateral Sclerosis (ALS). We used exon-sentive microarrays to characterize the responses to different mitochondrial perturbations in cellular models. We examined human SH-SY5Y neuroblastoma cells treated with paraquat, a neurotoxic herbicide which both catalyzes the formation of reactive oxygen species (ROS) and induces mitochondrial damage in animal models, and SH-SY5Y cells stably expressing the mutant SOD1(G93A) protein, one of the genetic causes of ALS. We identified a common set of genes that have a deregulated transcription and alternative splicing in both models. Noticeably, pathway analysis revealed that the expression of a subset of genes involved in neuritogenesis and axon guidance is perturbed, suggesting that alterations of axonal function may descend directly from mitochondrial damage and be responsible for neurodegenerative conditions.
Mutant SOD1 and mitochondrial damage alter expression and splicing of genes controlling neuritogenesis in models of neurodegeneration.
Cell line
View SamplesWhole-genome profiling of SH-SY5Y cells was done on neuroblastoma SH-SY5Y stably transfected with cDNAs coding for SOD1WT or the mutant SOD1(G93A) protein.
Mutant SOD1 and mitochondrial damage alter expression and splicing of genes controlling neuritogenesis in models of neurodegeneration.
Cell line
View SamplesHuman SH-SY5Y neuroblastoma cells treated with paraquat, a neurotoxic herbicide which both catalyzes the formation of reactive oxygen species (ROS) and induces mitochondrial damage in animal models was profiled using Affimetrix Exon 1.0 ST GeneChips
Mutant SOD1 and mitochondrial damage alter expression and splicing of genes controlling neuritogenesis in models of neurodegeneration.
Cell line
View SamplesE-cadherin, a protein encoded by the CDH1 gene is the dominant epithelial cell adhesion molecule playing a crucial role in epithelial tissue polarity and structural integrity. The progression of 90% or more carcinomas is believed to be mediated by disruption of normal E-cadherin expression, subcellular localization or function. Despite the strong correlation between E-cadherin loss and malignancy the mechanism through how this occurs is not known in most sporadic and hereditary epithelial carcinomas. Previous works have shown the importance of CDH1 intron 2 sequences for proper gene and protein expression supporting the possibility of these being cis-modulators of E-cadherin expression/function. but when co-expressed it led to reduced cell-cell adhesiveness, increased invasion and angiogenesis. By expression array analysis, IFITM1 and IFI27 levels were found to be increased upon CDH1a overexpression. Importantly, CDH1a was found to be de novo expressed in gastric cancer cell lines when compared to normal stomach.
Transcription initiation arising from E-cadherin/CDH1 intron2: a novel protein isoform that increases gastric cancer cell invasion and angiogenesis.
Specimen part, Cell line
View SamplesHepatocellular carcinoma (HCC) represents a major health problem as it afflicts an increasing number of patients worldwide. Albeit most of the risk factors for HCC are known, this is a deadly syndrome with a life expectancy at the time of diagnosis of less than 1 year. Definition of the molecular principles governing the neoplastic transformation of the liver is an urgent need to facilitate the clinical management of patients, based on innovative methods to detect the disease in its early stages and on more efficient therapies. In the present study we have combined the analysis of a murine model and human samples of HCC to identify genes differentially expressed early in the process of hepatocarcinogenesis, using a microarray based approach. Expression of 190 genes was impaired in murine HCC from which 65 were further validated by low-density array RT PCR. The expression of the best 45 genes was then investigated in human samples resulting in 18 genes which expression was significantly modified in HCC. Among them, JUN, methionine adenosyltransferase 1A and 2A, phosphoglucomutase 1, and acyl CoA dehydrogenase short branched chain indicate defective cell proliferation as well as one carbon pathway, glucose and fatty acid metabolism, both in HCC and cirrhotic liver, a well known preneoplastic condition. These alterations were further confirmed in public transcriptomic datasets from other authors. In addition, vasodilator stimulated phosphoprotein, an actin-associated protein involved in cytoskeleton remodelling, was also found to be increased in the liver and serum of cirrhotic and HCC patients. In addition to revealing the impairment of central metabolic pathways for liver homeostasis, further studies may probe the potential value of the reported genes for the early detection of HCC.
A signature of six genes highlights defects on cell growth and specific metabolic pathways in murine and human hepatocellular carcinoma.
Specimen part
View SamplesDerivation of embryonic stem cells (ESC) genetically identical to a patient by somatic cell nuclear transfer (SCNT) holds the potential to cure or alleviate the symptoms of many degenerative diseases while circumventing any immunorejection issues. However, no primate nuclear transfer embryonic stem (ntES) cell lines have been derived to date. Here, we used a modified SCNT technique to produce rhesus macaque SCNT blastocysts at a relatively high efficiency from adult donor cells and we successfully derived two primate ntES cell lines from 304 oocytes (an overall efficiency of 0.7%). Nuclear and mitochondrial DNA analysis confirmed the ntES cell lines were derived from rhesus monkey SCNT blastocysts and both rhesus monkey ntES cell lines exhibited a normal ESC morphology, expressed key stemness markers, were transcriptionally indistinguishable from control ESC lines and differentiated into multiple cell types. This is, to our knowledge, the first confirmed derivation of primate ntES cell lines.
Producing primate embryonic stem cells by somatic cell nuclear transfer.
No sample metadata fields
View SamplesEKLF is a Krppel-like transcription factor identified as a transcriptional activator and chromatin modifier in erythroid cells. EKLF-deficient (Eklf -/-) mice die at day 14.5 of gestation from severe anemia. In this study, we demonstrate that early progenitor cells fail to undergo terminal erythroid differention in Eklf -/- embryos. To discover potential EKLF target genes responsible for the failure of erythropoiesis, transcriptional profiling was performed with RNA from wild type and Eklf -/- early erythroid progenitor cells. These analyses identified significant perturbation of a network of genes involved in cell cycle regulation, with the critical regulator of the cell cycle, E2f2, at a hub. E2f2 mRNA and protein levels were markedly decreased in Eklf -/- early erythroid progenitor cells, which showed a delay in the G1-to-S-phase transition. Chromatin immunoprecipitation analysis demonstrated EKLF occupancy at the proximal E2f2 promoter in vivo. Consistent with the role of EKLF as a chromatin modifier, EKLF binding-sites in the E2f2 promoter were located in a region of EKLF-dependent DNase I sensitivity in early erythroid progenitor cells. We propose a model in which EKLF-dependent activation and modification of the E2f2 locus is required for cell cycle progression preceding terminal erythroid differentiation.
Failure of terminal erythroid differentiation in EKLF-deficient mice is associated with cell cycle perturbation and reduced expression of E2F2.
Age, Specimen part
View SamplesThe molecular chaperone HSP90 aids the maturation of a diverse but select set of metastable protein clients, many of which are key to a variety of signal transduction pathways. HSP90 function has been best investigated in animal and fungal systems, where inhibition of the chaperone has exceptionally diverse effects, ranging from reversing oncogenic transformation to facilitating the acquisition of drug resistance. Inhibition of HSP90 in the model plant Arabidopsis thaliana uncovers novel morphologies dependent on normally cryptic genetic variation and increases stochastic variation inherent to developmental processes. The biochemical activity of HSP90 is strictly conserved between animals and plants. However, the substrates and pathways dependent on HSP90 in plants are poorly understood. Progress has been impeded by reliance on light-sensitive HSP90 inhibitors due to redundancy in the A. thaliana HSP90 gene family. Here we present phenotypic and genome-wide expression analyses of A. thaliana with constitutively reduced HSP90 levels achieved by RNAi targeting. HSP90 reduction affects a variety of quantitative life-history traits, including flowering time and total seed set, and decreases developmental stability. Further, by quantitative analysis of morphological phenotypes, we demonstrate that HSP90-reduction increases phenotypic diversity in both seedlings and adult plants. Several morphologies are synergistically affected by HSP90 and growth temperature. Genome-wide expression analyses also suggest a central role for HSP90 in the genesis and maintenance of plastic responses. The expression results are substantiated by examination of the response of HSP90-reduced plants to attack by caterpillars of the generalist herbivore Trichoplusia ni. HSP90 reduction potentiates a more robust herbivore defense response. In sum, we propose that HSP90 exerts global effects on the environmental responsiveness of plants to many different stimuli. The comprehensive set of HSP90-reduced lines described here is a vital instrument to further examine the role of HSP90 as a central interface between organism, development, and environment.
Phenotypic diversity and altered environmental plasticity in Arabidopsis thaliana with reduced Hsp90 levels.
Age, Specimen part
View Samples