Gene expression analysis of 12 B-cell Chronic Lymphocytic Leukemia samples and 5 CD19+ control samples
ABSTRACT: Elevated levels of microRNA miR-155 represent a candidate pathogenic factor in chronic B-lymphocytic leukemia (B-CLL). In this study, we present evidence that MYB (v-myb myeloblastosis viral oncogene homolog) is overexpressed in a subset of B-CLL patients. MYB physically associates with the promoter of MIR155 host gene (MIR155HG, also known as BIC, B-cell integration cluster) and stimulates its transcription. This coincides with the hypermethylated histone H3K4 residue and spread hyperacetylation of H3K9 at MIR155HG promoter. Our data provide evidence of oncogenic activities of MYB in B-CLL that include its stimulatory role in MIR155HG transcription. We have studied differentially expressed genes in the whole genome and also in the preselected groups of MYB target genes and miR-155 microRNA predicted targets. This study was intended to investigate differentially expressed genes mRNA in 12 B-CLL patient peripheral blood samples in comparison with 5 CD19+ healthy donor peripheral blood samples.
Project description:Elevated levels of microRNA miR-155 represent a candidate pathogenic factor in chronic B-lymphocytic leukemia (B-CLL). In this study, we present evidence that MYB (v-myb myeloblastosis viral oncogene homolog) is overexpressed in a subset of B-CLL patients. MYB physically associates with the promoter of MIR155 host gene (MIR155HG, also known as BIC, B-cell integration cluster) and stimulates its transcription. This coincides with the hypermethylated histone H3K4 residue and spread hyperacetylation of H3K9 at MIR155HG promoter. Our data provide evidence of oncogenic activities of MYB in B-CLL that include its stimulatory role in MIR155HG transcription. We have studied differentially expressed genes in the whole genome and also in the preselected groups of MYB target genes and miR-155 microRNA predicted targets. Overall design: This study was intended to investigate differentially expressed genes mRNA in 12 B-CLL patient peripheral blood samples in comparison with 5 CD19+ healthy donor peripheral blood samples.
Project description:MicroRNA-155 is frequently over-expressed in CLL and is associated with worse clinical prognosis. To understand the role of miR-155 in CLL pathogenesis, we used microarrays to identify genes that are expressed at significantly lower levels in CLLs that harbor higher levels of miR-155 expression in an attempt to determine the relevant gene targets of miR-155 in CLL. MiR-155 levels of 38 CLL samples were determined and ranked. 6 CLLs with the highest and 6 CLLs with the lowest miR-155 within the IgVH unmutated group, and 5 CLLs with the highest and 5 CLLs with the lowest miR-155 within the IgVH mutated group were selected for Affymetrix array analyses.
Project description:Transcription profiles were compared according to the gender of CLL patients as well as according to the sensitivity of CLL cells to undergo or not DNA damage-induced apoptosis in vitro.
Project description:<TO BE UPDATED> Chronic lymphocytic leukaemia (CLL) is a common, adult B-cell leukaemia that has challenges in prognosis and treatment. It is characterised by a heterogeneous clinical course with multiple distinct phenotypes currently defined genetically or with target-specific monoclonal antibodies. While many studies have examined specific protein targets or global mRNA expression in CLL, few have attempted to characterise expression across the whole proteome. To achieve a non-biased, global proteomics characterisation, 14 CLL samples representing the genetic mutant subgroups NOTCH1, SF3B1 and WT, were subjected to quantitative mass spectrometry and compared with normal B cells using two isobaric tag experiments (TMT 10-plex). 6150 proteins were fully quantitated revealing a strong correlation between the regulated proteins across the CLL samples, independent of subtype. >800 proteins demonstrated significant upregulation (p<0.05) across the CLL samples. In addition to several novel cell surface markers, overexpressed proteins were strongly indicative of dysregulation to mRNA processing, spliceosome activity, transcriptional control by RNA pol II and epigenetic mechanisms (all p<10-10). A strong enrichment was observed for proteins coded by chromosome 12, often observed with trisomy in CLL (p<0.001). Downregulated proteins included cell adhesion molecules such as integrins and suggested a reduced capacity for endothelial transmigration (both p<10-10). These findings confirm many previous observations of CLL-specific protein overexpression (eg. CD5, ROR1, matriptase) and identify several novel surface targets for investigation. They also suggest that strong patterns of protein expression exist across CLL subtypes. Together, these results demonstrate the potential of proteomics and advocate the characterisation of further cancer samples by such methods.
Project description:It is unknown whether human lung T cells recirculate or belong to a distinct tissue-specific population. This issue is important for understanding their role in protection against viral infection and their contribution to pathophysiology of lung diseases such as chronic obstructive pulmonary disease. By comparing transcriptional profiles of blood and lung CD8+ T cells, we aimed to reveal specific traits of lung CD8+ T cells. A total of 12 samples was analyzed: 10 patient samples (including 1 technical replicate) and 2 reference samples (including 1 technical replicate). Per patient (in total 3 patients), 3 paired samples were analyzed. These samples were non-naive peripheral blood CD8+ T cells (CD45R0+CD3+CD8+ T cells), memory-type lung CD8+ T cells (CD45R0+CD27+CD3+CD8+ T cells) and effector-type lung CD8+ T cells (CD45R0+CD27-CD3+CD8+ T cells). The reference population consisted of a mix of naive peripheral blood CD8+ T cells from 5 healthy donors.
Project description:In order to investigate a potential involvement of miRNAs in BCR stimulation, in the present work we first evaluated their expression following IgM cross-linking in CLL cells, as well as in healthy B lymphocytes. Next, to infer putative miRNA targeting networks, we combined miRNA profiling results with gene expression and functional analyses miRNA expression profiling analysis by microarray analysis of CLL samples and pools of CD19+ cells derived from healthy donors.
Project description:Epigenetic code modifications by histone deacetylase inhibitors (HDACi) have recently been proposed as potential new therapies for hematological malignancies. Chronic Lymphocytic Leukemia (CLL) remains incurable despite the introduction of new treatments. CLL cells are characterized by an apoptosis defect rather than excessive proliferation, but proliferation centers have been found in organs such as bone marrow and lymph nodes. Here, we investigated gene expression modifications in CLL cells following treatment with valproic acid (VPA), a well-tolerated anti-epileptic drug with HDAC inhibitory activity. Experiment Overall Design: CLL cells obtained from 14 patients were treated in vitro with a concentration of 1mM VPA for 4 hours. VPA effects on gene expression were thereafter studied using Affymetrix technology
Project description:Autoimmune thyroid diseases (AITD) are the most common group of autoimmune diseases, associated with lymphocyte infiltration and the production of thyroid autoantibodies, like thyroid peroxidase antibodies (TPOAb), in the thyroid gland. Immunoglobulins (Igs) and cell-surface receptors are glycoproteins with distinctive glycosylation patterns that play a structural role in maintaining and modulating their functions. We investigated associations of total circulating IgG and peripheral blood mononuclear cells (PBMCs) glycosylation with AITD and the influence of genetic background. The study revealed an inverse association of IgG core fucosylation with TPOAb and PBMCs antennary α1,2 fucosylation with AITD, but no shared genetic variance between AITD and glycosylation. These data suggest that the decreased level of IgG core fucosylation is a risk factor for AITD that promotes antibody-dependent cell-mediated cytotoxicity (ADCC) associated with TPOAb levels
Project description:Most E2F-binding sites repress transcription through the recruitment of Retinoblasoma (RB) family members until the end of the G1 cell-cycle phase. Although the MYB promoter contains an E2F-binding site, its transcription is activated shortly after the exit from quiescence, before RB family members inactivation, by unknown mechanisms. We had previously uncovered a nuclear factor distinct from E2F, Myb-sp, whose DNA-binding site overlapped the E2F element and had hypothesized that this factor might overcome the transcriptional repression of MYB by E2F-RB family members. We have purified Myb-sp and discovered that Myc-associated zinc finger proteins (MAZ) are major components. We show that various MAZ isoforms are present in Myb-sp and activate transcription via the MYB-E2F element. Moreover, while forced RB or p130 expression repressed the activity of a luciferase reporter driven by the MYB-E2F element, co-expression of MAZ proteins not only reverted repression, but also activated transcription. Finally, we show that MAZ binds the MYB promoter in vivo, that its binding site is critical for MYB transactivation, and that MAZ knockdown inhibits MYB expression during the exit from quiescence. Together, these data indicate that MAZ is essential to bypass MYB promoter repression by RB family members and to induce MYB expression.
Project description:Effect of Epstein Barr infection on gene expression in B cells derived from tonsils, cord blood or peripheral blood 72 hours after infection. B cells either purified labelled as B cells or mononuclear cells isolates labelled as lympho