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. 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:A subtype of diffuse large B-cell lymphoma (DLBCL), termed activated B-cell-like (ABC) DLBCL, depends on constitutive NF-kB pathway signaling for survival. Small molecule inhibitors of IkB kinase b (IKKb), a key regulator of the NF-kB pathway, kill ABC DLBCL cells and hold promise for the treatment of this lymphoma type. We conducted an RNA interference genetic screen to investigate potential mechanisms of resistance of ABC DLBCL cells to IKKb inhibitors. We screened a library of small hairpin RNAs (shRNAs) targeting 500 protein kinases for shRNAs that would kill an ABC DLBCL cell line in the presence of a small molecule IKKb inhibitor more effectively than in its absence. Two independent shRNAs targeting IKKa synergized with the IKKb inhibitor to kill three different ABC DLBCL cell lines but were not toxic by themselves. Surprisingly, IKKa shRNAs blocked the classical rather than the alternative NF-kB pathway in ABC DLBCL cells, as judged by inhibition of IkBa phosphorylation. IKKa shRNA toxicity was reversed by coexpression of wild type but not kinase inactive forms of IKKa, suggesting that IKKa may directly phosphorylate IkBa under conditions of IKKb inhibition. These results suggest that therapy for ABC DLBCL may be improved by targeting both IKKa and IKKb. Keywords: compound treatment design Gene expression profiling of OCI-Ly3 cells with or without expressing IKKa shRNA in the presence or absence of 12.5 uM IKKb inhibitor for 2 and 3 days. Four samples were analyzed.
Project description:Analysis of five Notch signaling-dependent human T-ALL cell lines (ALLSIL, DND41, HPBALL, KOPTK1, TALL-1) treated with gamma-secretase inhibitor (GSI) to block Notch signaling. Samples include parental cells, cells rescued by retroviral transduction with ICN (a GSI-independent form of activated Notch1), and cells retrovirally transduced with c-Myc (an important downstream target of Notch1). Results allow segregation of bona fide Notch targets from other genes affected by gamma-secretase inhibition as well as from targets downstream of c-Myc. Thirty samples were analyzed. Five human T-ALL cell lines (ALLSIL, DND41, HPBALL, KOPTK1, TALL-1) were treated with gamma-secretase inhibitor (1.0 micromolar compound E) vs. DMSO vehicle control for 12 hours. Each cell line was also retrovirally transduced with ICN or c-Myc, FACS sorted, and then treated with GSI vs. DMSO.
Project description:Macrophages play a pivotal role in the immune system through recognition and elimination of microbial pathogens. Toll-like receptors (TLRs) on macrophages interact with microbial substances and initiate signal transduction through intracellular adapters. TLR4, which is important for the response to lipopolysaccharide (LPS), triggers downstream signaling mediators and eventually activates IkB kinase (IKK) complex and mitogen-activated protein kinases (MAPKs) such as p38. Previous reports revealed that, in addition to NF-kB, the induction of some LPS-inducible genes in macrophages required another transcription factor whose activity depends on p38. However, these transcription factors remained to be identified. Among these genes, NF-kB and C/EBPβ, a p38 downstream transcription factor, were predicted to co-regulate genes in LPS-stimulated BMDMs. Based on the subsequent results of a chromatin immunoprecipitation assay, we demonstrated that Tnfaip3 is regulated by both NF-kB and p38-dependent C/EBPβ. These results elucidate our understanding of the tight regulation of innate immunity. In order to identify p38-activated transcription factors that cooperate with NF-kB in response to LPS stimulation, microarrays were used to identify genes regulated by both NF-kB and p38 using wild-type, IKK-depleted, and p38 inhibitor-treated mouse bone marrow-derived macrophages (BMDMs). In silico analysis of transcription factor binding sites was used to predict the potential synergistic transcription factors from the co-expressed genes.
Project description:To quantify functional enhancers, we performed STARR-seq (Self-Transcribing Active Regulatory Region sequencing) in the U2OS-GR and the U2OS-AR cell lines (derived from U2OS ATTC:HTB-96, stably transfected with an expression construct for rat GR or human AR, respectively). U2OS-GR cells were treated with dexamethasone (1 µM) or vehicle (ethanol) for 14 hours. U2OS-AR cells were treated with R1881 (5 nM) or vehicle (DMSO) for 14 hours. To limit the number of putative enhancers, the STARR library contained genomic regions isolated by FAIRE (Formaldehyde Assisted Isolation of Regulatory Elements) from dexamethasone-treated U2OS-GR cells to include regions that gain accessibility upon GR activation. We added unique molecular identifiers (UMIs) during the reverse transcription stage to facilitate quantitative measurements of enhancer activity for each fragment. The UMI for each read is present within the sequence identifier line (directly following the y coordinate and separated by a ':') of the fastq files.
Project description:We found that the cancer testis antigen, ZNF165, is required for viability and can modulate TGFβ-induced gene expression in mesenchymal, Claudin-Low, TNBC. We employed the Affymetrix microarray platform to uncover transcriptionally modulated genes following ZNF165 depletion and TGFβ stimulation using the Claudin-low TNBC tumor-derived cell lines, SUM159 as a model. Our results provide insight into how ZNF165 globally modulates TGFβ signaling. We used microarray analysis to uncover the transcriptional network controlled by ZNF165 and clarify the role of ZNF165 in global TGFβ signaling SUM159 and WHIM12 cells were reverse transfected with either non-targeting or ZNF165 siRNA. For SUM159 cells, sixty hours post-transfection, cells were exposed to TGFβ for 3 hours. For WHIM12, forty eight hours post-transfection, cells were exposed to TGFβ for 3 hours. Total RNA was isolated and hybridized on to Affymetrix microarrays. Each experiment was repeated three times.
Project description:Gain-of-function mutations in NOTCH1 are common in T-cell lymphoblastic leukemias making this receptor a promising target for drugs such as gamma-secretase inhibitors (GSI), which block a proteolytic cleavage required for NOTCH1 activation. However, the enthusiasm for these therapies has been tempered by tumor resistance and the paucity of information on the oncogenic programs regulated by oncogenic NOTCH1. Analysis of gene expression in GSI-responsive and GSI-resistant cell lines treated with Compound E identifies differential resopnses to GSI. Keywords: Drug response Samples for microarray analysis were prepared and hybridized in Affymetrix Human U133 Plus 2.0 arrays according to the manufacturerâs instructions and as previously described. RNA was extracted from duplicate cultures of GSI-sensitive (ALL-SIL, CUTLL1, DND41, HPB-ALL, KOPTK1) and GSI-resistant (CCRF-CEM, MOLT3, P12 ICHIKAWA, PF382 and RPMI8402) T-ALL cell lines treated for 24 h with vehicle (DMSO) or 500 nM CompE. Interarray intensity differences were normalized with Dchip.
Project description:The expression of CTAs is normally restricted to gametogenic tissue but is often reactivated in the tumorigenic setting. This tumorigenic reactivation is thought to be due to global demethylation events during tumorigenesis. To test this, we employed an affymetrix microarray in the hypermethylated colorectal carcinoma tumor-derived cell line, HCT116, following 5-aza-2'-deoxycytidine treatment. We used microarray analysis to uncover genes whose expression is modulated by DNA methylation in the colorectal carcinoma tumor derived cell line, HCT116. HCT116 cells were exposed to 5-aza-2'-deoxycytidine for 72 hours. Total RNA was isolated and hybridized on to Affymetrix microarrays.
Project description:Evaluate modulation in gene expression modulation upon UGT1A_i2 knockdown in basal conditions and also under pharmacological treatment (SN-38) 6 samples in duplicate (12 samples total); HT115 colorectal cell line was infected with either UGT1A_i2 shRNA or non-target shRNA and left untreated or treated with either vehicle or SN-38 (0.5 uM)