HOX proteins are widely involved in hematopoietic development. These transcription factors combine a conserved DNA-binding homeobox with a divergent N-terminus that mediates interaction with variable cofactors. The resulting combinatorial diversity is thought to be responsible for mammalian HOX specificity. Contrasting this proposed mechanism for normal HOX function, here we demonstrate that, in the context of hematopoietic immortalization and leukemogenesis, individual HOX properties are govern ...[more]
Project description:CHQ5B primary human myoblasts obtained from Dr V. Mouly (Paris, France) have been described previously (Faulkner et al., 1999). Ankrd2 is upregulated on differentiation of myoblasts. The change in gene expression was studied in cells silenced for Ankrd2 (infected with AAV-shAnkrd2), control cells (infected with AAV-shLuc) and control cells uninfected.
Project description:Background<br>Primitive brain tumors are the first cause of cancer-related death in children. Tumor cells with stem-like properties (TSCs), thought to account for tumorigenesis and therapeutic resistance, have been isolated from high-grade gliomas in adults. Whether TSCs are a common component of pediatric brain tumors and are of clinical relevance remains to be determined. <br>Methodology/Principal findings<br>Tumor cells with self-renewal properties were isolated with cell biology techniques from a majority of 55 pediatric brain tumors samples, regardless of their histopathologies and grades of malignancy (57% of embryonal tumors, 57% of low-grade gliomas and neuro-glial tumors, 70% of ependymomas, 91% of high-grade gliomas). The vast majority (10/12) of high-grade glioma-derived oncospheres sustained long-term self-renewal numbers akin to neural stem cells (>7 self-renewals), whereas cells with limited renewing abilities akin to neural progenitors dominated in all other tumor types. Regardless of tumor entities, the young age group was associated with self-renewal properties akin to neural stem cells (P=0.05, chi-square test). TSCs shared a complex molecular profile combining embryonic stem cell markers with elements controlling neural stem cell properties and epithelio-mesenchymal transitions. They were radio- and chemoresistant and formed aggressive tumors after intracerebral grafting. Survival analysis of the cohort showed an association between isolation of TSCs with long-term self-renewal abilities and a patients higher mortality rate (P = 0.022, log-rank test). Patients bearing cells with limited self-renewal properties constituted an intermediate group of survival but which did not reach statistical significance. <br>Conclusions/Significance<br>In brain tumors affecting adult patients, TSC have been isolated only from high-grade gliomas. In contrast, our data show that tumor cells with stem cell-like or progenitor-like properties can be isolated from a wide range of histological sub-types and grades of pediatric brain tumors. They suggest that cellular mechanisms fueling tumor development differ between adult and pediatric brain tumors.<br>
Project description:Mouse bone marrow cells were infected with retrovirus for doxycylin-controllable AML1a expression, and cultured in vitro. Cells were treated with doxycycline to silence AML1a expression or left untreated to keep AML1a expression on, and subjected to microarray analysis to profile transcripts AML1a influences.
Project description:Generation of monocyte-derived dendritic cells (DC). Immature DC were prepared from peripheral blood mononuclear cells (PBMCs) isolated from whole blood of healthy donors. A minimum of 3 individual donor blood was used for each experiment. PBMCs were incubated with anti-CD14 microbeads (Miltenyi Biotec, Bergish Gladbach, Germany) as specified in the manufacturer's instructions. The isolated monocytes were resuspended at 10^6 cells/ml in medium supplemented with 10% human AB serum, 100 ng/ml GM-CSF (Leucomax; Novartis, Camberley, UK) and 50 ng/ml IL-4 (Peprotech EC Ltd, London, UK), cultured in tissue culture flasks. On day 7 the cells were defined as immature DC with low/intermediate HLA-DR expression. Microarray analysis of the effects of Paclitaxel and LPS on DC. Total RNA was extracted from day 7 DC which had been treated for 2 h with 1 ug/ml LPS or 100 uM paclitaxel for 2 h then washed and returned to culture for 24 h. This was used as a template to generate Cy3-labelled cRNA, using the Low RNA Input Linear Amplification Kit (Agilent). This was used as a probe on the Whole Human Genome Microarray (4x44K) slide (Agilent). Slides were scanned using the Agilent scanner and data extracted using Feature Extraction Software 9.5.3 (Agilent). Subsequent data analysis was performed using GeneSpring GX software.
Project description:Macrophages and dendritic cells (DC) are key components of cellular immunity and, as per the current model, originate from hemopoietic stem cells (HSCs). However, microglia were recently shown to originate from precursors that precede the appearance of HSCs. We thus re-investigated macrophage development and their relationship to HSCs and yolk sac (YS) precursors.