We performed DNA methylation (HELP array) and gene expression profiling in 69 samples of diffuse large B cell lymphoma (DLBCL). First, by gene expression, two molecular subtypes of DLBCL termed as "germinal center B cell-like" (GCB) and "activated B cell-like" (ABC) DLBCL were assigned to the 69 DLBCL cases. Then, the supervised analysis using HELP data revealed strikingly different DNA promoter methylation patterns in the two molecular DLBCL subtypes. These data provide epigenetic evidence that the DLBCL subtypes are distinct diseases that utilize different oncogenic pathways.
DNA methylation signatures define molecular subtypes of diffuse large B-cell lymphoma.
Sex, Age, Specimen part
View SamplesHeat shock protein 90 (Hsp90) is an emerging therapeutic target in cancer. We report that Hsp90 inhibitors selectively kill DLBCLs that are biologically dependent on the BCL6 transcriptional repressor. We examined the pharmacokinetics, toxicity and efficacy of PUH71, a recently developed purine scaffold Hsp90 inhibitor. PUH71 preferentially accumulated in tumors vs. normal tissues, and unlike the widely used benzoquinone Hsp90 inhibitors, displayed no signs of organ toxicity. PUH71 selectively and potently induced the regression of BCL6-dependent DLBCLs in vivo, through reactivation of key BCL6 target genes and apoptosis.
A purine scaffold Hsp90 inhibitor destabilizes BCL-6 and has specific antitumor activity in BCL-6-dependent B cell lymphomas.
No sample metadata fields
View SamplesWe have found that thyroid hormones (THs), acting as soluble integrin avß3 ligands, activate growth-related signaling pathways in T-cell lymphomas (TCL). Specifically, TH-activated avß3 integrin signaling promotes TCL proliferation and angiogenesis, in part, via the up-regulation of VEGF. Overall design: CUTLL1 cells were treated with T3- and T4-bound agarose or agarose alone for 24hrs. Total RNA was harvested from cells and used for expression profiling via RNA-seq.
Integrin αvβ3 acting as membrane receptor for thyroid hormones mediates angiogenesis in malignant T cells.
No sample metadata fields
View SamplesIn order to investigate the function of STAT5 in ALL, we isolated bone marrow cells from STAT5 fl/fl mice and transformed them with BCR-ABL1. In a second transduction the BCR-ABL1 driven pre-B cells were transformed either with CRE-GFP or empty vector control (GFP) and subjected to gene expression analysis.
BCL6-mediated repression of p53 is critical for leukemia stem cell survival in chronic myeloid leukemia.
Age, Disease, Disease stage
View SamplesThis analysis focused on identifying factors that protect pre-B cells against DNA double strand break (DSB)-mediated DNA damage stress during pre-B cell differentiation. Differentiation of pre-B cells including immunoglobulin light chain gene recombination were performed by withdrawal of interleukin-7 (IL-7) from IL-7-dependent murine pre-B cells or by inhibition of the BCR-ABL1 kinase activity in BCR-ABL1-transformed pre-B cells.
BCL6 is critical for the development of a diverse primary B cell repertoire.
Specimen part
View SamplesThe Philadelphia chromosome (Ph) encodes the oncogenic BCR-ABL1 tyrosine kinase, which defines a subset of acute lymphoblastic leukemia (ALL) with a particularly unfavorable prognosis. In this study, the tyrosine kinase inhibitor imatinib was used for pharmacological inhibition of BCR-ABL1. Gene expression profiles of Ph+ ALL cell lines were analyzed in response to imatinib treatment.
BCL6 enables Ph+ acute lymphoblastic leukaemia cells to survive BCR-ABL1 kinase inhibition.
Specimen part, Cell line
View SamplesThe Philadelphia chromosome (Ph) encodes the oncogenic BCR-ABL1 tyrosine kinase, which is present in almost every patient with chronic myeloid leukemia. In this study, the tyrosine kinase inhibitor Imatinib was used for pharmacological inhibition of BCR-ABL1. Gene expression profiles of CML cell lines were analyzed in response to Imatinib treatment.
BCL6 enables Ph+ acute lymphoblastic leukaemia cells to survive BCR-ABL1 kinase inhibition.
Specimen part, Cell line
View SamplesAggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo. Overall design: We found that eIF4E activity regulates the nuclear export of BCL6, MYC, and BCL2 in DH/TH DLBCLs. To determine the extent of nuclear eIF4E activity in DH/TH DLBCLs and how these programs can support the oncogenic activity of BCL6, MYC and/or BCL2 transcripts, we conducted eIF4E-RIP of nuclear RNA followed by RNA-sequencing in OCI-Ly1 cells in triplicates. To understand the changes in gene expression after ribavarin in a clinically relevant sample, we generated a patient-derived xenograft (PDX) in NSG mice from a de-identified specimen isolated from a patient prior to treatment harboring a triple-hit ABC-type DLBCL. PDX cells from passage four (PDX-4) were implanted into NSG mice. When tumors were palpable, mice were randomized to receive vehicle or 80 mg/kg/b.i.d. ribavarin intraperitoneally for 10 days. We isolated RNA from tumors treated with vehicle (n=2) or ribavarin (n=2) and performed mRNA-seq.
Combinatorial targeting of nuclear export and translation of RNA inhibits aggressive B-cell lymphomas.
No sample metadata fields
View SamplesBCL6 inhibitor induces derepression of BCL6 target genes and shows a similar transcriptional program to BCL6 siRNA Overall design: Genome-wide profiling of mRNA transcript levels in human DLBCL cell line with BCL6 inhibitor and DMSO control.
Rationally designed BCL6 inhibitors target activated B cell diffuse large B cell lymphoma.
Specimen part, Subject
View SamplesRationale: The BCL6 oncogene is constitutively activated by chromosomal translocations and amplification in ABC-DLBCLs, a class of DLBCLs that respond poorly to current therapies. Yet the role of BCL6 in maintaining these lymphomas has not been investigated. BCL6 mediates its effects by recruiting corepressors to an extended groove motif. Development of effective BCL6 inhibitors requires compounds exceeding the binding affinity of these corepressors. Objectives: To design small molecule inhibitors with superior potency vs. endogenous BCL6 ligands for unmet putative therapeutic needs such as targeting ABC-DLBCL. Findings: We used an in silico drug design functional-group mapping approach called SILCS to create a specific BCL6 inhibitor with 10-fold greater potency than endogenous corepressors. The compound, called FX1, binds in such a way as to occupy an essential region of the BCL6 lateral groove. FX1 disrupts BCL6 repression complex formation, reactivates BCL6 target genes, and mimics the phenotype of mice engineered to express BCL6 with lateral groove mutations. This compound eradicated established DLBCLs xenografts at low doses. Most strikingly, FX1 suppressed ABC-DLBCL cells as well as primary human ABC-DLBCL specimens ex vivo. Conclusions: ABC-DLBCL is a BCL6 dependent disease that can be targeted by novel inhibitors able to exceed the binding affinity of natural BCL6 ligands. Overall design: gene expression profiles of DLBCL cases
Rationally designed BCL6 inhibitors target activated B cell diffuse large B cell lymphoma.
Specimen part, Subject
View Samples