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.
MYB transcriptionally regulates the miR-155 host gene in chronic lymphocytic leukemia.
Specimen part, Disease, Disease stage
View SamplesComparison of CLL and MCL primary cells obtained from a patient with MCL variant Richter syndrome
Mantle cell lymphoma-variant Richter syndrome: Detailed molecular-cytogenetic and backtracking analysis reveals slow evolution of a pre-MCL clone in parallel with CLL over several years.
Specimen part, Disease, Disease stage
View SamplesActivated B-cell-like (ABC) and germinal center B-cell-like (GCB) diffuse large B-cell lymphoma (DLBCL) represent the two major molecular DLBCL subtypes. They are characterized by differences in clinical course and by divergent addiction to oncogenic pathways. To determine activity of novel compounds in these two subtypes, we conducted an unbiased pharmacologic in vitro screen. The phosphatidylinositol-3-kinase (PI3K) alpha/delta (PI3Ka/d) inhibitor AZD8835 showed marked potency in ABC DLBCL models, whereas the protein kinase B (AKT) inhibitor AZD5363 induced apoptosis in PTEN-deficient DLBCLs. These in vitro results were confirmed in various cell line xenograft and patient-derived xenograft mouse models in vivo. Treatment with AZD8835 induced inhibition of nuclear factor kappa-B (NF-kB) signaling, prompting us to combine AZD8835 with the Brutons tyrosine kinase (BTK) inhibitor ibrutinib. This combination was highly synergistic and effective both in vitro and in vivo. In contrast, the AKT inhibitor AZD5363 was effective in PTEN-deficient DLBCLs through downregulation of the oncogenic transcription factor MYC. Collectively our data suggest that patients should be stratified according to their oncogenic dependencies when treated with PI3K and AKT inhibitors.
Sensitivity to PI3K and AKT inhibitors is mediated by divergent molecular mechanisms in subtypes of DLBCL.
Cell line, Treatment
View SamplesMantle cell lymphoma (MCL) is a mature B-cell lymphoma characterized by poor clinical outcome. Recent studies revealed the importance of BCR signaling in maintaining MCL survival. However, it remains unclear which role MALT1, an essential component of the CARD11-BCL10-MALT1 (CBM) complex that transfers BCR signaling to the NF-kB pathway, plays in the biology of MCL. Here we show that a subset of MCLs is addicted to MALT1, as its inhibition by either RNA or pharmacologic interference induced cytotoxicity both in vitro and in vivo. Gene expression profiling following MALT1 inhibition demonstrated that MALT1 controls a MYC-driven gene expression network predominantly through increased MYC protein stability. Thus our analyses identify a previously unappreciated regulatory mechanism of MYC expression. Investigating primary mouse splenocytes, we could demonstrate that MALT1 induced MYC regulation is not restricted to MCL, but represents a common mechanism of MYC regulation. MYC itself is pivotal for MCL survival as its downregulation and pharmacologic inhibition induced cytotoxicity in all MCL models. Collectively, these results provide a strong mechanistic rationale to investigate the therapeutic efficacy in targeting the MALT1-MYC axis in MCL patients.
B-cell receptor-driven MALT1 activity regulates MYC signaling in mantle cell lymphoma.
Specimen part, Cell line
View SamplesExposure to Polychlorobiphenyls (PCBs) is known to cause serious health effects in human but the gene expression profiles leading to development of differnet diseases and disorders are not fully understood. The knowledge of global gene expression will help us to devlop early disease or disorder biomarkers for PCB induced health effects.
Transcriptional profiling and biological pathway analysis of human equivalence PCB exposure in vitro: indicator of disease and disorder development in humans.
Sex, Age, Specimen part, Treatment
View SamplesExposure to polychlorobiphenyls (PCBs) is known to cause serious health effects in human but the gene expression profiles leading to development of different diseases and disorders are not fully understood. The knowledge of global gene expression will help us to develop early disease or disorder biomarkers for PCB-induced health effects.
Differential gene expression and a functional analysis of PCB-exposed children: understanding disease and disorder development.
Sex, Age, Specimen part, Race
View SamplesExposure to Persistant Organic Pollutants (POPs) is known to cause serious health effects in human but the gene expression profiles leading to development of differnet diseases and disorders are not fully understood. The knowledge of global gene expression will help us to devlop early disease or disorder biomarkers for POP induced health effects.
Analysis of the toxicogenomic effects of exposure to persistent organic pollutants (POPs) in Slovakian girls: correlations between gene expression and disease risk.
Sex, Age, Specimen part, Race
View Samples