Project description:Genome wide transcript and target gene profiling reveal that FOXP1 acts directly and indirectly by enforcing known ABC-DLBCL hallmarks, including Chronically Activated B cell receptor Signaling (CABS) and the classical NF-κB survival pathway. Our data further suggest that FOXP1 maintains ABC-subtype distinction by repressing gene expression programs dominant in GCB-DLBCL and support a model in which the normally transitory B cell plasmablast is the target of ABC-DLBCL transformation. ChIP sequenicng was performed for the FOXP1 transcription factor in DLBCL cell lines. Input was sequenced and used as a control.
Project description:The goal of this study is to identify the effect of the transcription factor STAT3 in the two major subtypes of diffuse large B cell lymphoma (DLBCL). STAT3 is a signal transducer that, when dysregulated, becomes a powerful oncogene found in many human cancers, including DLBCL. DLBCL is the most common form of non-Hodgkin’s lymphoma and has two major subtypes: germinal center B-cell-like (GCB) and activated B-cell-like (ABC). When compared to the GCB form, ABC lymphomas respond much more poorly to current therapies and often exhibit overexpression or overactivation of STAT3. To investigate how STAT3 might contribute to this aggressive phenotype, we have used ChIP-Seq to identify STAT3 binding sites in 8 DLBCL cell lines (4 GCB subtype, 4 ABC) that are derived from patient tumors. 10,337 distinct STAT3 binding regions are occupied in at least two of the eight cell lines. One third (n = 3524) are differentially bound by STAT3 between the two subtypes (FDR < 0.05). More BRs are strongly bound in ABC than in GCB: 44% of differentially bound BRs (n = 1550) show more STAT3 binding in GCB, while 56% (n = 1974) are more strongly bound in ABC. Identification and comparison of STAT3 transcription factor binding sites in 8 cell lines that represent the 2 subtypes of DLBCL. 4 cell lines are subtyped as ABC and 4 are subtyped as GCB. 2-9 replicates and 1 input control are present for each cell line. (Cell line OCI-Ly19 was not included in the final analysis because RNA-Seq showed that its gene expression clustered in between the subtypes, probably due to its EBV+ status. However, its peak calls were used in intermediate steps of the analysis pipeline. Its sequencing runs have been included for completeness.)
Project description:Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma, including two main molecular subtypes termed activated B cell-like (ABC) and germinal center B cell-like (GCB). ABC DLBCL is less curable and identification of new molecular targets is needed for the development of effective therapeutic agents. Here, we focused on EGR1, a transcription factor that is regulated by the B cell receptor and JAK1/STAT3 signaling pathway in ABC DLBCL. ChIP-Seq and RNA-Seq analyses revealed that gene regulation by EGR1 in ABC DLBCL accentuates multiple oncogenic pathways, including MYC and E2F, while dampening the lethal type I IFN pathway.
Project description:Genome wide transcript and target gene profiling reveal that FOXP1 acts directly and indirectly by enforcing known ABC-DLBCL hallmarks, including Chronically Activated B cell receptor Signaling (CABS) and the classical NF-κB survival pathway. Our data further suggest that FOXP1 maintains ABC-subtype distinction by repressing gene expression programs dominant in GCB-DLBCL and support a model in which the normally transitory B cell plasmablast is the target of ABC-DLBCL transformation.
Project description:JAK kinases classically signal by activating STAT transcription factors, but can also regulate gene expression by epigenetically phosphorylating histone H3 on tyrosine 41 (H3Y41-P). In diffuse large B cell lymphomas (DLBCL), JAK signaling is a feature of the ABC subtype and is triggered by autocrine production of IL-6 and IL-10. Whether this signaling involves STAT activation, epigenetic modification of chromatin or both mechanisms is unknown. Here we use genetic and pharmacological inhibition to show that JAK1 signaling sustains the survival of ABC DLBCL cells. While STAT3 contributed to the survival of ABC DLBCL cell lines, forced STAT3 activity could not protect these cells from death following JAK1 inhibition, suggesting epigenetic JAK1 action. JAK1 regulated the expression of nearly 3,000 genes in ABC DLBCL cells, and the chromatin surrounding many of these genes was modified by H3Y41-P marks that were diminished by JAK1 inhibition. These JAK1 epigenetic target genes encode important regulators of ABC DLBCL proliferation and survival, including IRF4, MYD88 and MYC. A small molecule JAK1 inhibitor cooperated with the BTK inhibitor ibrutinib in reducing IRF4 levels and acted synergistically to kill ABC DLBCL cells, suggesting that this combination should be evaluated in clinical trials.