Project description:Pharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. Here, we demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Phenotypic effects are preceded by the direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4 and the subsequent down-regulation of the IRF4 transcriptional program. Ectopic expression of IRF4 antagonizes the phenotypic effects of CBP/EP300 bromodomain inhibition and prevents the suppression of the IRF4 target c-MYC. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network. Through the use of CBP/EP300 bromodomain inhibitors (CBP/EP300i), we demonstrate that MYC expression in BETi-resistant cells is dependent on CBP/EP300 bromodomains and that treatment with CBP/EP300i restores phenotypic sensitivity.
Project description:Multiple Myeloma (MM) is a frequently incurable hematological cancer in which over activity of MYC plays a central role, notably through upregulation of ribosome biogenesis and translation. To better understand the oncogenic program driven by MYC and investigate its potential as a therapeutic target, we screened a chemically diverse small molecule library for anti-MM activity. The most potent hits identified were rocaglate-scaffold inhibitors of translation initiation. Expression profiling of MM cells revealed reversion of the oncogenic MYC-driven transcriptional program by CMLD010509, our most promising rocaglate. Proteome-wide, reversion correlated with selective depletion of short-lived proteins key to MM growth and survival, most notably MYC, MDM2, CCND1, MAF and MCL-1. The efficacy of CMLD010509 in mouse models of MM confirmed the therapeutic relevance of these findings in vivo and supports the feasibility of targeting the oncogenic MYC-driven translation program in MM with rocaglates.
Project description:Pharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. Here, we demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Phenotypic effects are preceded by the direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4 and the subsequent down-regulation of the IRF4 transcriptional program. Ectopic expression of IRF4 antagonizes the phenotypic effects of CBP/EP300 bromodomain inhibition and prevents the suppression of the IRF4 target c-MYC. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network. A total of 13 ChIP-seq samples were sequenced. Samples were treated with control (DMSO) or test compound (2.5 uM SGC-CBP30 or 0.25uM CPI267203) for 6 hours. Signal from input samples was included to subtract background signal from each ChIP-seq sample. Antibodies used were against p300, H3K18ac, H3K27ac, or BRD4.
Project description:Pharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. Here, we demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Phenotypic effects are preceded by the direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4 and the subsequent down-regulation of the IRF4 transcriptional program. Ectopic expression of IRF4 antagonizes the phenotypic effects of CBP/EP300 bromodomain inhibition and prevents the suppression of the IRF4 target c-MYC. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network.
Project description:Pharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. Here, we demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Phenotypic effects are preceded by the direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4 and the subsequent down-regulation of the IRF4 transcriptional program. Ectopic expression of IRF4 antagonizes the phenotypic effects of CBP/EP300 bromodomain inhibition and prevents the suppression of the IRF4 target c-MYC. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network.
Project description:The overexpression of PIM kinases in hematologic malignancies, including multiple myeloma, make PIM inhibitors an attractive therapeutic strategy for these diseases. Recent preclinical data from our group demonstrated the anti-myeloma effect of the pan-PIM kinase inhibitor PIM447, along with its synergistic effect with standard of care anti-myeloma agents. Based on those previous data, we have evaluated here the in vitro and in vivo activity of the triple combination of PIM447 + pomalidomide + dexamethasone (PIM-Pd). Our results show that this combination exerts a potent anti-myeloma effect in vitro, even in presence of microenvironment cells, and, in vivo, it markedly delays tumor growth and prolongs survival. Mechanism of action studies suggest that the combination PIM-Pd inhibits protein translation processes through the convergent inhibition of mTORC1, which disrupts the function eIF4E, and c-Myc. As a consequence, cell cycle arrest and disruption of metabolic pathways, including glycolysis and lipid biosynthesis, is induced, inhibiting myeloma cell proliferation. Altogether, these data support the potential future clinical development of the triple combination PIM-Pd for the treatment of patients with MM.
Project description:NSD2, a histone lysine methyltransferase, is overexpressed as a result of the t(4;14) translocation that is associated with 15-20% of multiple myeloma. Earlier studies have indicated that NSD2 may be involved in myelomagenesis and suggested that it may be a target for myeloma therapy. Here we show that NSD2 is required for clonogenic growth, adherence and proliferation on bone marrow stroma, and tumorigenesis of t(4;14)+ but not t(4;14)- myeloma cells, in a methyltransferase activity dependent manner. Furthermore, we found that PHD domains are important for NSD2 cellular activity and biological functions by recruiting it to oncogenic gene loci and driving downstream transcription activation events. These results strengthened the disease link of NSD2 and provided a basis that targeting NSD2 may be a therapeutic strategy in multiple myeloma patients with t(4;14) translocation. Our data also revealed multiple domains in the protein for possible chemical modulation. To elucidate the mechanisms underlying the oncogenic potential of NSD2 in myeloma, we performed microarray analysis on KMS11 parental (PAR), TKO and 8 reconstituted lines. Based on the whole-genome expression profile, the 10 samples clearly fell into 4 clusters – (1) PAR; (2) TKO; (3) WT, WT+MMSET I, 526-1240 and 526-1365; and (4) CDM, CDM+MMSET I, MMSET I and H762Y Biological triplicates of cell cultures of indicated lines were harvested in TRIzol (Invitrogen) and characterized by human U133 plus 2.0 Affymetrix GeneChip. The gene expression data was normalized using the Robust Multiarray Averaging (RMA) method and log2 transformed before comparisons.
Project description:Multiple myeloma is a fatal hematological malignancy. In order to develop effective therapeutic approaches, it is critical to understand the pathogenesis of myeloma. The Radl 5T model of multiple myeloma is a clinically relevant murine model where myeloma spontaneously occurs in aged, in-bred C57BlKalwRij mice and can be propagated by intravenous inoculation of 5T myeloma cells into mice of the same strain. Importantly inoculation of 5T myeloma cells into C57Bl6 mice does not result in myeloma, demonstrating that the bone marrow (BM) microenvironment of the C57BlKalwRij strain provides a unique and permissive milieu for myeloma development. We hypothesized that cells of the BM microenvironment may provide essential stimuli for the development of multiple myeloma in vivo. We aim to determine the differences in expression within the bone marrow of C57Bl/KalwRij mice. Comparison of C57Bl/KalwRij mouse bone marrow to C57BL6 mouse bone marrow
Project description:Myeloma bone disease is characterized by tremendous bone destruction with suppressed bone formation. IL-3 is a multifunctional cytokine that increases myeloma cell growth and osteoclast proliferation while inhibiting osteoblast differentiation. While IL-3 appears to be an attractive therapeutic target for myeloma, attempts at targeting IL-3 have been unsuccessful due to IL-3M-bM-^@M-^Ys effects on normal hematopoiesis. Thus identification of IL-3M-bM-^@M-^Ys downstream effects in MMBD is important for effective targeting of this cytokine in MM. Here we demonstrated that treatment of myeloma patient CD14+ bone marrow monocyte / macrophages with IL-3 induces high levels of Activin A (ActA), a pluripotent TGF-M-NM-2 superfamily member that, like IL-3, modulates MMBD by enhancing osteoclastogenesis and inhibiting osteoblasts. We show that IL-3 induced osteoclastogenesis is mediated by ActA and is RANKL independent. Additionally, IL-3 induced ActA secretion is greatest early in osteoclastogenesis and ActA acts early in osteoclastogenesis. Therefore we suggest that therapies targeting ActA production should block IL-3M-bM-^@M-^Ys effects in myeloma bone disease. Investigate the mediators of IL-3M-bM-^@M-^Ys effects on bone remodeling in myeloma we performed gene expression profiling using Affymetrix GeneChip analysis of IL-3 treated CD14+ peripheral blood from healthy donor.