Microarray data of mouse MLL-AF10 leukemia cells with or without IKK inhibitor treatment
Ontology highlight
ABSTRACT: MLL fusion proteins in leukemia induce aberrant transcriptional elongation and associated chromatin perturbations, however the upstream signaling pathways and activators that recruit or retain MLL oncoproteins at initiated promoters are unknown. Through functional and comparative genomic studies, we identified an essential role for NF-kB signaling in MLL leukemia. Suppression of NF-kB led to robust anti-leukemia effects that phenocopied loss of functional MLL oncoprotein or associated epigenetic cofactors. The NF-kB subunit RELA occupies promoter regions of crucial MLL target genes and sustains the MLL-dependent leukemia stem cell program. IKK/NF-kB signaling is required for wild-type MLL and fusion protein retention and maintenance of associated histone modifications providing a molecular rationale for enhanced efficacy in therapeutic targeting of this pathway in MLL leukemias. MLL-AF10 cells were treated with 0.5µM IKK inhibitor or vehicle. Each group contains triplicate samples.
Project description:MLL fusion proteins in leukemia induce aberrant transcriptional elongation and associated chromatin perturbations, however the upstream signaling pathways and activators that recruit or retain MLL oncoproteins at initiated promoters are unknown. Through functional and comparative genomic studies, we identified an essential role for NF-kB signaling in MLL leukemia. Suppression of NF-kB led to robust anti-leukemia effects that phenocopied loss of functional MLL oncoprotein or associated epigenetic cofactors. The NF-kB subunit RELA occupies promoter regions of crucial MLL target genes and sustains the MLL-dependent leukemia stem cell program. IKK/NF-kB signaling is required for wild-type MLL and fusion protein retention and maintenance of associated histone modifications providing a molecular rationale for enhanced efficacy in therapeutic targeting of this pathway in MLL leukemias. MV4;11 cells were treated with 1µM IKK inhibitor or vehicle. Each group contains triplicate samples
Project description:MLL fusion proteins in leukemia induce aberrant transcriptional elongation and associated chromatin perturbations, however the upstream signaling pathways and activators that recruit or retain MLL oncoproteins at initiated promoters are unknown. Through functional and comparative genomic studies, we identified an essential role for NF-kB signaling in MLL leukemia. Suppression of NF-kB led to robust anti-leukemia effects that phenocopied loss of functional MLL oncoprotein or associated epigenetic cofactors. The NF-kB subunit RELA occupies promoter regions of crucial MLL target genes and sustains the MLL-dependent leukemia stem cell program. IKK/NF-kB signaling is required for wild-type MLL and fusion protein retention and maintenance of associated histone modifications providing a molecular rationale for enhanced efficacy in therapeutic targeting of this pathway in MLL leukemias.
Project description:MLL fusion proteins in leukemia induce aberrant transcriptional elongation and associated chromatin perturbations, however the upstream signaling pathways and activators that recruit or retain MLL oncoproteins at initiated promoters are unknown. Through functional and comparative genomic studies, we identified an essential role for NF-kB signaling in MLL leukemia. Suppression of NF-kB led to robust anti-leukemia effects that phenocopied loss of functional MLL oncoprotein or associated epigenetic cofactors. The NF-kB subunit RELA occupies promoter regions of crucial MLL target genes and sustains the MLL-dependent leukemia stem cell program. IKK/NF-kB signaling is required for wild-type MLL and fusion protein retention and maintenance of associated histone modifications providing a molecular rationale for enhanced efficacy in therapeutic targeting of this pathway in MLL leukemias.
Project description:The inhibitor of kB kinase (IKK) is the master regulator of the nuclear factor kB (NF-kB) pathway, involved in inflammatory, immune and apoptotic responses. In the ‘canonical’ NF-kB pathway, IKK phosphorylates inhibitor of kB (IkB) proteins and this triggers ubiquitin-mediated degradation of IkB, leading to release and nuclear translocation of NF-B transcription factors.
The data presented show that the IKK and IKK subunits recognize a YDDX docking site located within the disordered C-terminal region of IkBa. Our results also suggest that IKK contributes to the docking interaction with higher affinity as compared to IKK.
Project description:Mitogen activated protein kinase kinase kinase 1 (MAP3K1), is involved in various cancer signaling networks including the NF-B, JNK, ERK, and p38 pathways. Functioning as a signaling kinase in these oncogenic pathways, MAP3K1 contributes to tumor growth and metastasis. Additionally, higher transcript levels of MAP3K1 in pancreatic patient tumors is associated with poorer 5-year survival, suggesting MAP3K1 is an attractive therapeutic target. Activation of inhibitor of nuclear factor NF-κB kinase subunit-β (IKK), an important phosphorylation target of MAP3K1, was shown to be important in pancreatic cancer (PC) disease onset and progression. We previously reported a quinoxaline analog, Analog 84, which inhibits IKK phosphorylation and downstream NF-B pathway activation. To improve the metabolic stability and bioavailability of Analog 84, we developed 51-106, which moved -F atom to block a site of potential metabolism. Using a chemoproteomics approach for kinome profiling, KiNativTM, we show 51-106 selectively binds to MAP3K1 in an ATP-competitive manner. Follow up studies show 51-106 inhibits downstream phosphorylation of IKK and blocks TNF-induced MAP3K1-IKK-mediated NF-B activity. Treatment of PC cell lines MiaPaCa2 and PANC-1 with 51-106 inhibits cell growth and migration with low micromolar potency. Utilizing 51-106 as a tool to study MAP3K1 signaling, we use phosphoproteomics analysis to show MAP3K1 inhibition leads to a dose dependent decrease in NPM1 T199 phosphorylation, suggesting NPM1 may play a role in MAP3K1 signaling. We observe a dose-dependent S-phase arrest in cells treated with 51-106, potentially linking MAP3K1 inhibition to a dysfunctional DNA damage response. Consistent with this observation, in combination studies, 51-106 synergistically inhibited growth with gemcitabine in LSL-KrasG12D/+, LSL-Trp53R172H/+, Pdx1-Cre (KPC) cell lines in vitro and in KPC syngeneic orthotopic implantation mouse model of pancreatic cancer in vivo. Our data indicated that MAP3K1 inhibition may represent a promising therapeutic in PC. These findings underscore the need for further investigation into the molecular interactions and downstream effects of the MAP3K1-NPM1 signaling axis.
Project description:Mutations in KRAS occur in a variety of tumors of epithelial origin, driving the oncogenic phenotype.The NF-kB transcription factor pathway is important for oncogenic RAS to transform cells and to drive tumorigenesis in animal models. Recently TAK1, an upstream regulator of IKK which controls canonical NF-kB, was shown to be important for chemoresistance in pancreatic cancer and for regulating KRAS+ colorectal cancer cell growth and survival. Here we show that GSK-3alpha is upregulated by KRAS leading to interaction with TAK1 to stabilize the TAK1/TAB complex to promote IKK activity. Additionally, GSK-3alpha is required for promoting critical non-canonical NF-kB signaling in pancreatic cancer cells. Pharmacologic inhibition of GSK-3 suppresses growth of human pancreatic tumor explants, consistent with loss of expression of genes such as c-myc and TERT. These data identify GSK-3alpha as a key downstream effector of oncogenic RAS via its ability to coordinately regulate distinct NF-kB signaling pathways GSK-3 inhibition at 2 and 8 hours
Project description:The RNA-binding protein RC3H1 (also known as ROQUIN) promotes TNFalpha mRNA decay via a 3'UTR constitutive decay element (CDE). Here, we applied PAR-CLIP to human RC3H1 to identify about 3800 mRNA targets with more than 16000 binding sites. A large number of sites are distinct from the consensus CDE and revealed a structure-sequence motif with U-rich sequences embedded in hairpins. RC3H1 binds preferentially short-lived and DNA damage induced mRNAs, indicating a role of this RNA-binding protein in the posttranscriptional regulation of the DNA damage response. Intriguingly, RC3H1 affects expression of NF-kB pathway regulators such as IkBalpha and A20. RC3H1 uses roquin and Zn-finger domains to contact a binding site in the A20 3'UTR, demonstrating a not yet recognized mode of RC3H1 binding. Knockdown of RC3H1 resulted in increased A20 protein expression, thereby interfering with IkB kinase and NF-kB activities, demonstrating that RC3H1 can modulate the activity of the IKK/NF-kB pathway.
Project description:The RNA-binding protein RC3H1 (also known as ROQUIN) promotes TNFalpha mRNA decay via a 3'UTR constitutive decay element (CDE). Here, we applied PAR-CLIP to human RC3H1 to identify about 3800 mRNA targets with more than 16000 binding sites. A large number of sites are distinct from the consensus CDE and revealed a structure-sequence motif with U-rich sequences embedded in hairpins. RC3H1 binds preferentially short-lived and DNA damage induced mRNAs, indicating a role of this RNA-binding protein in the posttranscriptional regulation of the DNA damage response. Intriguingly, RC3H1 affects expression of NF-kB pathway regulators such as IkBalpha and A20. RC3H1 uses roquin and Zn-finger domains to contact a binding site in the A20 3'UTR, demonstrating a not yet recognized mode of RC3H1 binding. Knockdown of RC3H1 resulted in increased A20 protein expression, thereby interfering with IkB kinase and NF-kB activities, demonstrating that RC3H1 can modulate the activity of the IKK/NF-kB pathway.
Project description:To identify the target genes of Runx1 in MLL fusion leukemia, we performed microarray analysis using control and Runx1-deficient MLL-ENL leukemia cells. Runx1 intact and excised bone marrow cells were transduced with MLL-ENL and transplanted into congenic mice. Leukemic cells were harvested from moribund mice, and gene expression was compared using 3 independent leukemia cells for each genotype.