Project description:To identify IRF4 transcription factor binding on chromatin at 5' regulatory regions of genes in myeloma cell line models. Keywords: binding site identification design Formaldehyde cross-linked, sonicated chromatin is prepared from cell lines Kms12 (test) and Ly19 (control). Chromatin immunoprecipated with anti-IRF4 antibody is labeled with Cy5 and co-hybridized on Agilent Human Promoter Set arrays with chromatin immunoprecipated with normal sera labeled with Cy3 . Two biological replicates were performed for the Kms12 and Ly19 experiments.
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:Despite being recognized as a major mesenchymal cell type and a key accomplice in myeloma progression, the precise roles of adipocytes in distinct stages of myeloma pathogenesis remain elusive. Here, we elucidate a critical role of adipocyte-derived β-hydroxybutyrate (β-OHB) in enabling myeloma cells to overcome glucose metabolic stress by sustaining the stability of interferon regulatory factor 4 (IRF4), a master oncoprotein essential for myeloma survival. Under glucose deprivation conditions, AMP-activated protein kinase (AMPK) activation disrupts the IRF4-heat shock protein 90 (HSP90) interaction, enabling the E3 ligase TRIM21-mediated IRF4 ubiquitination and proteasomal degradation. Adipocytes-secreted β-OHB counteracts this process by fueling 3-oxoacid CoA-transferase 1 (OXCT1)-dependent ketolysis and activating N- acetyltransferase 10 (NAT10) to acetylate IRF4 at lysine 87, thereby restoring IRF4-HSP90 binding and blocking TRIM21-mediated IRF4 degradation. Notably, pharmacological inhibition of OXCT1 or NAT10, combined with AMPK activator, synergistically suppresses myeloma growth in vitro and in vivo. Our study thus positions adipocytes-derived β-OHB as a critical metabolic adaptor that empowers myeloma cells to circumvent glucose metabolic stress and highlights a promising therapeutic avenue for targeting metabolic vulnerabilities in multiple myeloma.
Project description:Despite being recognized as a major mesenchymal cell type and a key accomplice in myeloma progression, the precise roles of adipocytes in distinct stages of myeloma pathogenesis remain elusive. Here, we elucidate a critical role of adipocyte-derived β-hydroxybutyrate (β-OHB) in enabling myeloma cells to overcome glucose metabolic stress by sustaining the stability of interferon regulatory factor 4 (IRF4), a master oncoprotein essential for myeloma survival. Under glucose deprivation conditions, AMP-activated protein kinase (AMPK) activation disrupts the IRF4-heat shock protein 90 (HSP90) interaction, enabling the E3 ligase TRIM21-mediated IRF4 ubiquitination and proteasomal degradation. Adipocytes-secreted β-OHB counteracts this process by fueling 3-oxoacid CoA-transferase 1 (OXCT1)-dependent ketolysis and activating N- acetyltransferase 10 (NAT10) to acetylate IRF4 at lysine 87, thereby restoring IRF4-HSP90 binding and blocking TRIM21-mediated IRF4 degradation. Notably, pharmacological inhibition of OXCT1 or NAT10, combined with AMPK activator, synergistically suppresses myeloma growth in vitro and in vivo. Our study thus positions adipocytes-derived β-OHB as a critical metabolic adaptor that empowers myeloma cells to circumvent glucose metabolic stress and highlights a promising therapeutic avenue for targeting metabolic vulnerabilities in multiple myeloma.
Project description:Despite being recognized as a major mesenchymal cell type and a key accomplice in myeloma progression, the precise roles of adipocytes in distinct stages of myeloma pathogenesis remain elusive. Here, we elucidate a critical role of adipocyte-derived β-hydroxybutyrate (β-OHB) in enabling myeloma cells to overcome glucose metabolic stress by sustaining the stability of interferon regulatory factor 4 (IRF4), a master oncoprotein essential for myeloma survival. Under glucose deprivation conditions, AMP-activated protein kinase (AMPK) activation disrupts the IRF4-heat shock protein 90 (HSP90) interaction, enabling the E3 ligase TRIM21-mediated IRF4 ubiquitination and proteasomal degradation. Adipocytes-secreted β-OHB counteracts this process by fueling 3-oxoacid CoA-transferase 1 (OXCT1)-dependent ketolysis and activating N- acetyltransferase 10 (NAT10) to acetylate IRF4 at lysine 87, thereby restoring IRF4-HSP90 binding and blocking TRIM21-mediated IRF4 degradation. Notably, pharmacological inhibition of OXCT1 or NAT10, combined with AMPK activator, synergistically suppresses myeloma growth in vitro and in vivo. Our study thus positions adipocytes-derived β-OHB as a critical metabolic adaptor that empowers myeloma cells to circumvent glucose metabolic stress and highlights a promising therapeutic avenue for targeting metabolic vulnerabilities in multiple myeloma.