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The synthetic glucocorticoids prednisolone and dexamethasone regulate the same genes in acute lymphoblastic leukemia cells [Set 2]

ABSTRACT: Background: Glucocorticoids (GCs) cause apoptosis in malignant cells of lymphoid lineage by transcriptionally regulating a plethora of genes. As a result, GCs are included in almost all treatment protocols for lymphoid malignancies, particularly childhood acute lymphoblastic leukemia (chALL). The most commonly used synthetic GCs in the clinical setting are prednisolone and dexamethasone. While the latter has a higher activity and more effectively reduces the tumor load in patients, it is also accompanied by more serious adverse effects than the former. Whether this difference might be explained by regulation of different genes by the two GCs has never been addressed. Results: Using a recently developed GC bioassay based on a GC-responsive reporter construct in human Jurkat T-ALL cells, we found ~7-fold higher biological activity with dexamethasone than prednisolone. Similarly, 1.0e-7M dexamethasone and 7.0e-7M prednisolone triggered similar cell death rates in CCRF-CEM-C7H2 T-chALL cells after 72 hours of treatment. Using microarray-based whole genome expression profiling and a variety of statistical and other approaches, we compared the transcriptional response of chALL cells to 6 hour exposure to both synthetic GCs at the above concentrations. Our experiments did not detect any gene whose regulation by dexamethasone differed significantly from that by prednisolone. Conclusions: Our findings suggest that the reported differences in treatment efficacy and cytotoxicity of dexamethasone and prednisolone are not caused by inherent differences of the 2 drugs to regulate the expression of certain genes, but rather result either from applying them in biologically in-equivalent concentrations and/or from differences in their pharmacokinetics and - dynamics resulting in different bioactivities in tumor cells and normal tissues.

ORGANISM(S): Homo sapiens

PROVIDER: GSE55877 | GEO | 2014/08/12

SECONDARY ACCESSION(S): PRJNA241191

REPOSITORIES: GEO

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Project description:Background: Glucocorticoids (GCs) cause apoptosis in malignant cells of lymphoid lineage by transcriptionally regulating a plethora of genes. As a result, GCs are included in almost all treatment protocols for lymphoid malignancies, particularly childhood acute lymphoblastic leukemia (chALL). The most commonly used synthetic GCs in the clinical setting are prednisolone and dexamethasone. While the latter has a higher activity and more effectively reduces the tumor load in patients, it is also accompanied by more serious adverse effects than the former. Whether this difference might be explained by regulation of different genes by the two GCs has never been addressed. Results: Using a recently developed GC bioassay based on a GC-responsive reporter construct in human Jurkat T-ALL cells, we found ~7-fold higher biological activity with dexamethasone than prednisolone. Similarly, 1.0e-7M dexamethasone and 7.0e-7M prednisolone triggered similar cell death rates in CCRF-CEM-C7H2 T-chALL cells after 72 hours of treatment. Using microarray-based whole genome expression profiling and a variety of statistical and other approaches, we compared the transcriptional response of chALL cells to 6 hour exposure to both synthetic GCs at the above concentrations. Our experiments did not detect any gene whose regulation by dexamethasone differed significantly from that by prednisolone. Conclusions: Our findings suggest that the reported differences in treatment efficacy and cytotoxicity of dexamethasone and prednisolone are not caused by inherent differences of the 2 drugs to regulate the expression of certain genes, but rather result either from applying them in biologically in-equivalent concentrations and/or from differences in their pharmacokinetics and - dynamics resulting in different bioactivities in tumor cells and normal tissues. Additional microarray data set with RNA from CCRF-CEM-C7H2 cells treated with 1.0e-7M dexamethasone, 4.0 and 8.0 e-6M Solu-dacortin (prednisolone 21-(sodium succinate), a water soluble prednisolone) and 0.1% ethanol.

Project description:Glucocorticoids (GCs) are commonly used to treat patients suffering from lymphoid malignancies i.e. leukemia and multiple myeloma. Although GCs are known to be strong inducers of apoptosis in lymphoid cells, the molecular determinants of GC therapy resistance are poorly understood. Although GC treatment triggers important changes in gene expression, few studies have addressed the regulatory role of small regulatory microRNAs (miRNAs) in GC therapy response. Only recently, aberrant microRNA expression has been linked to the development of haematological malignancies and microRNAs have become master regulators of drug resistance. We identified GC inducible mRNA and microRNA transcription profiles in GC sensitive MM1S as compared to GC resistant MM1R cells. Transcriptome analysis revealed that GCs regulate multiple genes involved in cell cycle control, cell organization and cell death in MM1S, which remain unaffected in MM1R cells. Correspondingly, GCs selectively trigger cell death in MM1S but not in MM1R. Out of 32 microRNAs responsive to GC in MM1S cells but not in MM1R cells, mir-150 was identified as the most persistent GC responsive microRNA. Furthermore, Ingenuity Pathways Analysis (IPA) revealed that ectopic transfection of a synthetic mir-150 mimics GC therapy response in MM1S cells, associated with selective changes in mRNA levels of typical GR transactivated and transrepressed target genes. Although mir-150 largely mirrors GC responsive changes in gene expression of the transcription factor Myb, GR chaperone FKBP5, cell cycle modulator proteins (IL23A, SKP2, CDKN1A), chemokine signaling proteins (CXCR4, CX3CR1, CCL3) and mTOR/UPR stress related proteins (DDIT4, TXNIP), we also observed mir-150 selective effects on transcription factors (NR3C2 (MR), Myb, Fos, Jun, C/EBP-beta, IRF4, NFE2L1, ATF3, ATF4,), chaperone molecules HSPA8, HSP90AB1), the sodium channel SCNN1G and UPR stress proteins (TRIB3, DDIT3). Remarkably, mir-150 overexpression was not able to overcome GC therapy resistance, since we could not detect GC like effects of mir-150 in GR (NR3C1) deficient MM1R cells. Altogether GC-inducible mir-150 adds a novel complex layer of regulation for fine tuning GC specific therapeutic responses in multiple myeloma.

Project description:Background: Glucocorticoids (GCs) are widely used anti-inflammatory drugs. While useful in clinical practice, patients taking GCs often suffer from skeletal side effects including growth retardation and decreased bone quality in adults. On a physiological level, GCs have been implicated in the regulation of chondrogenesis and osteoblast differentiation, as well as maintaining homeostasis in cartilage and bone. We identified the glucocorticoid receptor (GR) as a potential regulator of chondrocyte hypertrophy in a microarray screen of primary limb bud mesenchyme micromass cultures. Some targets of GC regulation in chondrogenesis are known, but the global effects of pharmacological GC doses on chondrocyte gene expression have not been comprehensively evaluated. Results: This study systematically identifies a spectrum of GC target genes in embryonic growth plate chondrocytes treated with synthetic GR agonist, dexamethasone (DEX), at 6 and 24 hrs. Conventional analysis of this data set and gene set enrichment analysis (GSEA) was performed. Transcripts associated with metabolism were enriched in the DEX condition along with extracellular matrix genes. In contrast, a subset of growth factors and cytokines were negatively correlated with DEX treatment. Comparing DEX-induced gene expression data to developmental changes in gene expression in micromass cultures revealed an additional layer of complexity in which DEX maintains the expression of certain chondrocyte marker genes while inhibiting factors that promote vascularization and ultimately ossification of the cartilaginous template. Conclusions: Together, these results provide insight into the mechanisms and major molecular classes functioning downstream of DEX in primary chondrocytes monolayers. In addition, comparison of our data with microarray studies of DEX treatment in other cell types demonstrated that the majority of DEX effects are tissue-specific. This study provides novel insights into the effects of pharmacological GC on chondrocyte gene transcription and establishes the basis for subsequent functional studies. Experiment Overall Design: Primary chondrocytes isolated from the tibiae, humeri and femurs of 15.5 day old mice are treated with 10EXP-7M DEX or an equal volume of the DMSO vehicle for 24 hrs. Total RNA is isolated after 6 hrs and 24 hrs of treatment. Samples from three independent experiments independent time courses were hybridized to Affymetrix MOE 430 2.0 mouse chips. Experiment Overall Design: Number of time points: 2 (6hr and 24 hr) Experiment Overall Design: Number of treatments: 2 (DEX and the vehicle control) Experiment Overall Design: Number of Samples: 3 replicates per time point per treatment Experiment Overall Design: Affymetrix chip: MOE 430 2.0 Experiment Overall Design: Cell type: Primary chondrocyte Experiment Overall Design: Tissue or origin: Tibiae, humerus, femur Experiment Overall Design: Species E15.5 mice Experiment Overall Design: Samples: Total RNA

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The synthetic glucocorticoids prednisolone and dexamethasone regulate the same genes in acute lymphoblastic leukemia cells [Set 2]

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