Project description:RNA interference screens identified the transcription factor IRF4 as essential for the survival of the activated B-cell-like subtype of diffuse large B-cell lymphoma (ABC-DLBCL). Analysis of IRF4 genomic targets in ABC-DLBCL and Multiple Myeloma (MM) revealed that IRF4 regulates distinct networks in these cancers. IRF4 peaks in ABC-DLBCL, but not MM, were enriched for a composite ETS-IRF DNA motif that can be bound by heterodimers of IRF4 and the ETS-family transcription factor SPIB, whose expression is also essential for ABC-DLBCL survival. Gene expression and ChIP-Seq analysis identified essential genes co-regulated by IRF4 and SPIB. Together, these factors regulate a critical oncogenic loop by activating CARD11, which controls ABC-DLBCL survival via the NF-kB pathway. The interaction between IRF4 and SPIB presents an attractive therapeutic target in this aggressive lymphoma.
Project description:Anaplastic large cell lymphoma (ALCL) is an aggressive, CD30+ T-cell lymphoma of children and adults. ALK fusion transcripts or mutations in the JAK-STAT pathway are observed in most ALCL tumors, but the mechanisms underlying tumorigenesis are not fully understood. Here we show that dysregulated STAT3, together with a core transcriptional regulatory circuit consisting of BATF3–IRF4–IKZF1, co-occupies gene enhancers to establish an oncogenic transcription program and maintain the malignant state of ALCL. Critical downstream targets of this network in ALCL cells include the proto-oncogene MYC, which requires active STAT3 to facilitate high levels of MYC transcription. The activity of this auto-regulatory transcription loop is reinforced by MYC binding to the enhancer regions associated with STAT3 and each of the core regulatory transcription factors. These findings provide new insights for understanding how dysregulated signaling pathways hijack cell-type-specific transcriptional machinery to drive tumorigenesis and create therapeutic vulnerabilities in genetically defined tumors.
Project description:Anaplastic large cell lymphoma (ALCL) is an aggressive, CD30+ T-cell lymphoma of children and adults. ALK fusion transcripts or mutations in the JAK-STAT pathway are observed in most ALCL tumors, but the mechanisms underlying tumorigenesis are not fully understood. Here we show that dysregulated STAT3, together with a core transcriptional regulatory circuit consisting of BATF3–IRF4–IKZF1, co-occupies gene enhancers to establish an oncogenic transcription program and maintain the malignant state of ALCL. Critical downstream targets of this network in ALCL cells include the proto-oncogene MYC, which requires active STAT3 to facilitate high levels of MYC transcription. The activity of this auto-regulatory transcription loop is reinforced by MYC binding to the enhancer regions associated with STAT3 and each of the core regulatory transcription factors. These findings provide new insights for understanding how dysregulated signaling pathways hijack cell-type-specific transcriptional machinery to drive tumorigenesis and create therapeutic vulnerabilities in genetically defined tumors.
Project description:Anaplastic large cell lymphoma (ALCL) is an aggressive, CD30+ T-cell lymphoma of children and adults. ALK fusion transcripts or mutations in the JAK-STAT pathway are observed in most ALCL tumors, but the mechanisms underlying tumorigenesis are not fully understood. Here we show that dysregulated STAT3, together with a core transcriptional regulatory circuit consisting of BATF3–IRF4–IKZF1, co-occupies gene enhancers to establish an oncogenic transcription program and maintain the malignant state of ALCL. Critical downstream targets of this network in ALCL cells include the proto-oncogene MYC, which requires active STAT3 to facilitate high levels of MYC transcription. The activity of this auto-regulatory transcription loop is reinforced by MYC binding to the enhancer regions associated with STAT3 and each of the core regulatory transcription factors. These findings provide new insights for understanding how dysregulated signaling pathways hijack cell-type-specific transcriptional machinery to drive tumorigenesis and create therapeutic vulnerabilities in genetically defined tumors.
Project description:Knowledge of essential oncogenic mutations can inspire therapeutic strategies that are synthetically lethal, affecting cancer cells bearing an oncogenic mutation while sparing normal cells. Lenalidomide is emerging as an active agent in diffuse large B cell lymphoma (DLBCL), especially for the activated B cell-like (ABC) subtype, but the mechanism of its action is unknown. Here we show that lenalidomide kills ABC DLBCL cells by augmenting the production of interferon 3/4, which these cells are predisposed to produce by their oncogenic MYD88 mutations. Lenalidomide stimulates the type I interferon pathway by suppressing IRF4, a repressor of IRF7. IRF4 is required for ABC DLBCL viability and is both a target and an amplifier of NF-kB signaling in this lymphoma subtype. Blockade of B cell receptor (BCR) signaling synergized with lenalidomide to reduce IRF4 levels, increase interferon 3/4 secretion, decrease NF-kB, and kill ABC DLBCL cells, suggesting therapeutic combinations that exploit the oncogenic signaling pathways in this cancer. For the OCILY10 cell line treated with 10 uM lenalidamide, a four point time course of 3, 6, 24, and 48 hours was analyzed (n=4). For the TMD8 cell line treated with 10 uM lenalidamide, a four point time course of 3, 6, 24, and 48 hours was analyzed (n=4).
Project description:We present evidence to support a new model of Anaplastic Large Cell Lymphoma (ALCL) pathogenesis in which the malignancy is initiated in early thymocytes, prior to TCR rearrangement which is bypassed in NPMâ??ALK transgenic mice following Notch1 expression. In support, we show that T cell receptor (TCR) rearrangements are aberrant in some human ALCL, yielding events that would not normally be permissive for survival during T cell development. However, a TCR is required for thymic egress and subsequent development of peripheral tumors in mice yet this TCR must be downâ??regulated for Tâ??cell lymphomagenesis. Children affected by ALCL may thus harbor lymphoma-initiating cells in the thymocyte population that seeds relapse after chemotherapy. comparative genomic hybridization data from 43 human Anaplastic Large Cell Lymphoma (ALCL) samples and control samples
Project description:The mechanisms underlying the pathogenesis of the constitutively active tyrosine kinase nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) expressing anaplastic large cell lymphoma are not completely understood. Here we show using an integrated phosphoproteomic and metabolomic strategy that NPM-ALK induces a metabolic shift toward aerobic glycolysis, increased lactate production, and biomass production. The metabolic shift is mediated through the anaplastic lymphoma kinase (ALK) phosphorylation of the tumor-specific isoform of pyruvate kinase (PKM2) at Y105, resulting in decreased enzymatic activity. Small molecule activation of PKM2 or expression of Y105F PKM2 mutant leads to reversal of the metabolic switch with increased oxidative phosphorylation and reduced lactate production coincident with increased cell death, decreased colony formation, and reduced tumor growth in an in vivo xenograft model. This study provides comprehensive profiling of the phosphoproteomic and metabolomic consequences of NPM-ALK expression and reveals a novel role of ALK in the regulation of multiple components of cellular metabolism. Our studies show that PKM2 is a novel substrate of ALK and plays a critical role in mediating the metabolic shift toward biomass production and tumorigenesis.
Research is published:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3739039/
Project description:Deregulation of chromatin modifiers, including DNA helicases, are emerging as one of the mechanism underlying the transformation of anaplastic lymphoma kinase negative (ALK−) anaplastic large cell lymphoma (ALCL). We recently identified the DNA helicase HELLS as central for proficient ALK-ALCL proliferation and progression. By performing RNA-sequencing profiling coupled with bioinformatic prediction, we demonstrated that HELLS contributes to an appropriate cytokinesis via the transcriptional regulation of genes involved in cleavage furrow regulation in ALK- anaplastic large cell lymphoma
Project description:Global proteomics profiling of anaplastic large cell lymphoma cell lines DEL, SU-DHL-1 (ALK+), Mac-1, Mac-2A (ALK-) as well as Hodgkin lymphoma cell lines L-428, L-540, L-1236 and HDLM-2.