Background: Glioblastoma multiforme (GBM) is the most aggressive and most lethal primary malignant brain tumor, correlated with survival rates of less than one year from the time of diagnosis. Current surgical procedure attempts to remove the bulk of the tumor mass, whereas GBM frequently recurs within 1-3cm from the primary tumor resection site. Molecular mechanisms involved in the recurrence of the tumor are still poorly understood. The aim of the study was to define the molecular signature of GBM surrounding white matter (WM) in order to better understand the molecular mechanisms involved with tumor relapse.
Gene expression profile of glioblastoma peritumoral tissue: an ex vivo study.
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View SamplesBACKGROUND: Several in vitro assays have been used to identify cancer stem cells (CSC), including expression of cell surface markers and Hoechst dye efflux properties. However, each of these methods has potential pitfalls that complicate interpretation of the results. Focusing on colon cancers (CC), the CD133 antigen has been proposed as a marker of colon CSC. However, conflicting results have been reported in the literature indicating the need of a systematic analysis of CSC within CC and a complete validation of markers for the isolation of these cells.
No associated publication
Specimen part, Cell line
View SamplesEpigenetic mechanisms contribute to deregulated gene expression of hematopoietic progenitors in Myelodysplastic Syndromes (MDS). Hypomethylating agents are able to improve peripheral cytopenias in MDS patients. To identify critical gene expression changes induced by hypomethylating agents, we analyzed gene expression profiling (GEP) of myelodysplastic and normal CD34+ hematopoietic stem cells treated in vitro with or without decitabine. Four MDS and two untreated early stage Hodgkins lymphomas were analyzed for GEP. Mock treated CD34+ stem cells segregate according to diagnosis and karyotype. After decitabine treatment, gene expression changes were more consistent on MDS CD34+ cells with abnormal kayotype. Comparing decitabine-induced genes with those found down-regulated in mock-treated MDS cells, we identified a list of candidate tumor suppressor genes in MDS. By real-time RT-PCR we confirmed expression changes for three selected genes CD9, CXCR4 and GATA2 in 12 MDS patients and 4 controls. CD9 was widely repressed in most MDS CD34+ cell samples, although similar levels of methylation were found in both normal and MDS total bone marrows. CXCR4 promoter methylation was absent in total bone marrows from 36 MDS patients. In conclusion, changes in gene expression changes induced by hypomethylating treatment are more pronounced in CD34+ cells from abnormal karyotype.
Gene expression profiling of myelodysplastic CD34+ hematopoietic stem cells treated in vitro with decitabine.
Sex, Age, Specimen part, Disease
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Muscle Expression of SOD1(G93A) Modulates microRNA and mRNA Transcription Pattern Associated with the Myelination Process in the Spinal Cord of Transgenic Mice.
Age, Specimen part
View SamplesEpigenetic changes play a role in the pathogenesis of myeloid malignancies and hypomethylating agents have shown efficacy in these diseases. We studied the apoptotic effect, the genome-wide methylation and gene expression profiles in HL60 cells following decitabine treatment, using micro-array technologies. Decitabine treatment resulted in a decrease in global DNA methylation, corresponding to 4876 probeset IDs with significantly reduced methylation levels, while expression of 2583 IDs was induced. The integrated analysis identified 160 genes demethylated and upregulated by decitabine, mainly including development and differentiation pathways genes. Genes target of polycomb group protein regulation were overrepresented in this group. Apoptosis was induced by decitabine and apoptosis-specific PCR arrays more precisely indicated decitabine-induced upregulation of 13 apoptosis-related genes, in particular Dap-kinase 1 and Bcl2L10. Correspondingly, in primary patient samples, BCL2L10 was hypermethylated in 45% of AML, 43% of therapy-related myeloid neoplasms, 12% of MDS and in none of the controls.
Analysis of genome-wide methylation and gene expression induced by 5-aza-2'-deoxycytidine identifies BCL2L10 as a frequent methylation target in acute myeloid leukemia.
Specimen part
View SamplesExpression profiling of lumbar spinal cord from MLC/SOD1G93A mice and age matched controls at 120 days of age. We used Affymetrix GeneChip Mouse Gene expression 2.0 st Array to determine differential gene expression.
No associated publication
Age, Specimen part
View SamplesWith the goal of specifically dissecting the toxicogenomic signatures of the helper-dependent (HD) human (HAd5) and canine (CAV-2) adenovirus, the VSV-G-pseudotyped SIN HIV-1 (LV) and the Adenoviral-associated vector 2/9 for human neurons (AAV2/9), we transduced a bona fide human neuronal system with HD-HAd5, HD-CAV-2, LV and AAV2/9, we analysed the transcriptional response of more than 47,000 transcripts using gene chips.
Differentiated neuroprogenitor cells incubated with human or canine adenovirus, or lentiviral vectors have distinct transcriptome profiles.
Specimen part
View SamplesBrain gene transfer using viral vectors will likely become a therapeutic option for several disorders. Helper-dependent (HD) canine adenovirus type 2 vectors (CAV-2) are well suited for this goal. Indeed, these vectors are poorly immunogenic, efficiently transduce neurons, are retrogradely transported to afferent structures in the brain, and lead to long-term transgene expression. CAV-2 vectors have been exploited to unravel behavior, cognition, neural networks, axonal transport and therapy for orphan diseases. Here we describe the HD-CAV-2 vector induced transcriptional response of human dopaminergic neurospheres derived from midbrain progenitors. In this 3D model system, brain cell functions and dynamics mimic several aspects the dynamic nature of human brain. With the goal of better understanding and characterizing HD CAV-2 for brain therapy, we analyzed the transcriptomic modulation induced by HD-CAV-2 in this brain model system.
Transcriptional Response of Human Neurospheres to Helper-Dependent CAV-2 Vectors Involves the Modulation of DNA Damage Response, Microtubule and Centromere Gene Groups.
Specimen part, Time
View SamplesAlthough intensification of chemotherapy approaches considerably increased the outcome of pediatric T-cell Acute Lymphoblastic Leukemia (T-ALL) patients, a subgroup of them still experience treatment failure and relapse. In this context, we hypothesized that the Nrf2 signalling and its downstream effectors could be involved in sustain therapy resistance in T-ALL, as previously reported in other cancers. Indeed, in this study we identified the Aldo-Keto Reductase (AKR) enzymes AKR1C1-3, as over-expressed in T-ALL samples from therapy-resistant patients, demonstrating their fundamental role in the control of the response to vincristine (VCR) treatment. In particular, we evidence that the modulation of AKR1C1-3 gene expression and activity is sufficient to strongly affect the sensitivity of T-ALL cell lines and primary cells to VCR treatment, but not to daunorubicin, cytarabine or L-asparaginase. Moreover, we found a correlation between the degree of VCR response and the amount of AKR1Cs expression in patient-derived T-ALL xenografts. Interestingly, we show that daunorubicin and cytarabine are able to induce the over-activation of AKR1C enzymes, thus establishing a potential resistance loop generated by the combination of these drugs during T-ALL treatment.
AKR1C enzymes sustain therapy resistance in paediatric T-ALL.
Specimen part, Disease stage
View SamplesJuvenile myelomonocytic leukemia (JMML) is a very rare and aggressive stem cell disease that mainly occurs in young children. RAS activation constitutes the core component of oncogenic signaling. In addition, the leukemic blasts of a quarter of JMML patients present with monosomy 7 (-7), whereas more than half of the patients show enhanced age-adjusted fetal hemoglobin (HbF) levels. Hematopoietic stem cell transplantation is the current standard of care. This results in an event-free survival of 50 - 60%, indicating that novel molecular driven therapeutic options are urgently needed. Using gene expression profiling in an extensive series of 82 patient samples, we aimed at understanding the molecular biology behind JMML and identified a previously unrecognized molecular subgroup characterized by high LIN28B expression.
LIN28B overexpression defines a novel fetal-like subgroup of juvenile myelomonocytic leukemia.
Disease
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