Project description:Searching for new strategies of acute myeloid leukemia (AML) treatment is of particular interest. Cell lines, e. g. HL-60 and NB4, represent model systems to study molecular features of leukemic cells. The all-trans-retinoic acid (ATRA) has proven itself to be an effective treatment for one of AML subtypes, i.e., acute promyelocytic leukemia (APL). At the same time, ATRA causes granulocytic differentiation of non-APL leukemic cells in vitro. Combination of new therapeutics with ATRA could improve efficiency of treatment. Studying the proteome perturbation in leukemic cells under the ATRA treatment allows to determine potential regulatory molecules that could be affected pharmacologically. Thus, the TMT-based proteomic profiles of HL-60, NB4, and K562 cell lines under the ATRA treatment were obtained at 0, 3, 12, 24, and 72 h after the ATRA treatment.
Project description:Treatment of acute promyelocytic leukemia (APL) with all-trans-retinoic acid (ATRA) results in terminal differentiation of leukemic cells toward neutrophil granulocytes. Administration of ATRA leads to massive changes in gene expression, including down-regulation of cell proliferation-related genes and induction of genes involved in immune function. One of the most induced genes in APL NB4 cells is transglutaminase 2 (TG2). RNAi-mediated stable silencing of TG2 in NB4 cells (TG2-KD NB4) coupled with whole genome microarray analysis revealed that TG2 is involved in the expression of a large number of ATRA-regulated genes. The affected genes participate in granulocyte functions and their silencing lead to reduced adhesive, migratory and phagocytic capacity of neutrophils and less superoxide production. The expression of genes related to cell cycle control also changed, suggesting that TG2 regulates myeloid cell differentiation. CC chemokines CCL2, 3, 22, 24 and cytokines IL1B and IL8 involved in the development of differentiation syndrome (DS) are expressed at significantly lower levels in TG2-KD NB4 cells than in wild-type NB4 cells upon ATRA treatment. Based on our results, we propose that reduced expression of TG2 in differentiating APL cells may suppress effector functions of neutrophil granulocytes and attenuate the ATRA-induced inflammatory phenotype of DS. We used microarrays to detail the global program of gene expression underlying ATRA-induced differentiation of TG2 knockout NB4 cells. TG2 knockout NB4 cells were differentiated for 48 and 72 hours in the presence of ATRA and their gene expression profiles were compared to the wild-type cells at the same time points. Undifferentiated wild-type and TG2 knockout NB4 cells were used as untreated controls. Three biological replicates each.
Project description:Treatment of acute promyelocytic leukemia (APL) with all-trans-retinoic acid (ATRA) results in terminal differentiation of leukemic cells toward neutrophil granulocytes. Administration of ATRA leads to massive changes in gene expression, including down-regulation of cell proliferation-related genes and induction of genes involved in immune function. One of the most induced genes in APL NB4 cells is transglutaminase 2 (TG2). RNAi-mediated stable silencing of TG2 in NB4 cells (TG2-KD NB4) coupled with whole genome microarray analysis revealed that TG2 is involved in the expression of a large number of ATRA-regulated genes. The affected genes participate in granulocyte functions and their silencing lead to reduced adhesive, migratory and phagocytic capacity of neutrophils and less superoxide production. The expression of genes related to cell cycle control also changed, suggesting that TG2 regulates myeloid cell differentiation. CC chemokines CCL2, 3, 22, 24 and cytokines IL1B and IL8 involved in the development of differentiation syndrome (DS) are expressed at significantly lower levels in TG2-KD NB4 cells than in wild-type NB4 cells upon ATRA treatment. Based on our results, we propose that reduced expression of TG2 in differentiating APL cells may suppress effector functions of neutrophil granulocytes and attenuate the ATRA-induced inflammatory phenotype of DS.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:ATRA was identified as a Pin1 inhibitor via fluorescence polarization-based high throughput screening. We performed microarray expression profiling to demonstrate the similarity between ATRA and Pin1 KD at the genome-wide level APL NB4 cells in response to ATRRA or inducible Pin1 knockdown for 3 days were collected for RNA extraction and hybridization on Affymetrix microarrays. We sought to validate in genome-wide level whether similarity occurred between ATRA and Pin1 knockdown-treated NB4 cells.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:The aim of this study is to identify microRNAs (miRNAs) transcriptionnally regulated by retinoic acid (RA). For that purpose we have used the RA-based treatment of the Acute Promyelocytic Leukemia (APL) as a model. This malignancy is characterised by a differentiation arrest of granulopoiesis at the promyelocytic stage. APL is molecularly associated with reciprocal translocations that always involve the retinoic acid receptor a (RARa). In the vast majority of APL cases, a t(15;17) chromosomal translocation fuses the genes encoding the promyelocytic leukemia protein PML and RARa. The resulting PML-RARa is a transcriptional repressor that impedes the expression of RA-regulated genes notably through an aberrant recruitment of transcriptional repressors and histone deacetylases. Consequently, these genes become insensitive to physiological doses (nanoM) of all-trans-retinoic acid (ATRA) but pharmacological doses (microM), overcome the PML-RARa-mediated repression and restore normal transcription and granulocytic differentiation. The restorative effects of RA can be reproduced in vitro in the NB4 cells, which were derived from an APL patient. These cells provide an excellent model to study the transcriptional deregulations that arise in APL and the molecular effects of the anti-cancerous RA-based treatment. We also used in this study the RA-resistant cells, namely NB4-LR1 and NB4-LR2 cells. The NB4-LR1 cells do transcriptionally respond to ATRA but do not maturate. In contrast, the NB4-LR2 cells show a clear defect in RA signaling, as they harbor a truncated form of PML-RAR protein that is not sensitive to pharmacological doses of RA. First, we plan to characterize miRNAs-repressed by PML-RAR. We reasoned that if some miRNAs are repressed by this protein, then pharmacological doses of RA should abolish this repression and lead to an increase in the level of expression of the corresponding miRNAs. NB4, NB4-LR1 and NB4-LR2 cells will thus be treated for 16h with ATRA (1 microM), and miRNAs profiles will be compared. We anticipate that, the expression of a potential miRNA-repressed by PML-RAR should be up-regulated by ATRA in both NB4 and NB4-LR1 cells but remain unchanged in NB4-LR2 cells. This expression pattern should in fact be similar to those observed for known RA-regulated genes, such as RARb, a well characterized target of the RARa and PML-RAR proteins. Importantly, this experimental procedure was already validated with the identification of a miRNA repressed by PML-RAR (patent Lecellier et al. #WO 2006/048553). MiRNAs candidates obtained will then be validated by chromatin immunoprecipitation using anti-RARa and anti-PML antibodies, followed by luciferase assays in presence or absence of ATRA. Keywords: retinoic acid-mediated gene regulation
Project description:NB4 is an APL derived cell line, carrying the t(15;17) translocation and expressing the PML/RARa fusion protein. Still, an important question that remains to be addressed is whether PML/RARa target genes are transcriptionally suppressed in primary APL cells and re-activated in all-trans retinoic acid (ATRA) treated NB4 cells. Gene expression of NB4 cells treated with ATRA at different time points were analyzed.