Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA119825 | ENA |
REPOSITORIES: ENA
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Project description:Abstract. Deregulated c-MYC is found in a variety of cancers where it promotes proliferation as well as apoptosis. In many hematological malignancies enhanced NF-kB exerts prosurvival functions. Here we investigated the role of NF-kB in mouse and human c-MYC-transformed lymphomas. The NF-kB-pathway is extinguished in murine lymphoma cells and extrinsic stimuli typically inducing NF-kB activity fail to activate this pathway. Genetic activation of the NF-kB pathway induces apoptosis in these cells, while inhibition of NF-kB by an IkBa superrepressor provides a selective advantage in vivo. Furthermore, in human Burkitt´s lymphoma cells we find that NF-kB activation induces apoptosis. NF-kB upregulates Fas and predisposes to Fas-induced cell death, which is caspase 8 mediated and can be prevented by CFLAR overexpression. We conclude that c-MYC overexpression sensitizes cells to NF-kB-induced apoptosis and persistent inacvtivity of NF-kB signaling is a prerequisite for MYC-mediated tumorigenesis. We could also show that low immunogenicity and Fas insensitivity of MYC driven lymphoma cells is reversed by activation of NF-kB. Our observations provide a molecular explanation for the described absence of the NF-kB signaling in Burkitt´s lymphoma and question the applicability of NF-kB inhibitors as candidates for treatment of this cancer. Experiment Overall Design: Ramos cells were transfected in triplicates with pRTS-GFP (A+,C+,D+) or pRTS-CA-IKK2 (E+,F+,H+), selected with hygromycin and transgene expression was induced with doxycycline (0,5mg/ml) for 48hrs. RNA was isolated with RNeasy mini kit (Qiagen, Venlo, Netherlands) and Gene expression profiling (GEP) was performed using Affymetrix Human Genome U133 Plus 2.0 Array (Affymetrix, Santa Clara, CA, USA). 2 µg of total RNA were labeled using the GeneChip® One-Cycle Target Labeling assay kit (Affymetrix). After hybridization arrays were stained and washed in a FS 450 Fluidics station (Affymetrix) before imaging on an Affymetrix GeneChip (3000) scanner. Raw data were generated using the GCOS 1.4 software (Affymetrix). Probe level data were obtained using the Robust Multichip Average (RMA) normalization algorithm and CEL files were loaded into Genesifter (GeneSifter.Net, VizX Laboratories, Seattle, WA, USA). Genes were identified as differentially expressed among the two classes if a two-sample T-test revealed a nominal significance level of 0.05 and the ratio between the two classes was at least 2 fold. Calculation of false discovery rate was done according to the method of Benjamini and Hochberg. Biological significance was determined using Gene Ontolgy reports.
2009-08-07 | E-GEOD-17129 | biostudies-arrayexpress
Project description:Pcgf6 suppresses Myc-induced lymphomagenesis
| PRJNA785557 | ENA
Project description:Abstract. Deregulated c-MYC is found in a variety of cancers where it promotes proliferation as well as apoptosis. In many hematological malignancies enhanced NF-kB exerts prosurvival functions. Here we investigated the role of NF-kB in mouse and human c-MYC-transformed lymphomas. The NF-kB-pathway is extinguished in murine lymphoma cells and extrinsic stimuli typically inducing NF-kB activity fail to activate this pathway. Genetic activation of the NF-kB pathway induces apoptosis in these cells, while inhibition of NF-kB by an IkBa superrepressor provides a selective advantage in vivo. Furthermore, in human Burkitt´s lymphoma cells we find that NF-kB activation induces apoptosis. NF-kB upregulates Fas and predisposes to Fas-induced cell death, which is caspase 8 mediated and can be prevented by CFLAR overexpression. We conclude that c-MYC overexpression sensitizes cells to NF-kB-induced apoptosis and persistent inacvtivity of NF-kB signaling is a prerequisite for MYC-mediated tumorigenesis. We could also show that low immunogenicity and Fas insensitivity of MYC driven lymphoma cells is reversed by activation of NF-kB. Our observations provide a molecular explanation for the described absence of the NF-kB signaling in Burkitt´s lymphoma and question the applicability of NF-kB inhibitors as candidates for treatment of this cancer.
2009-07-22 | GSE17129 | GEO
Project description:Pcgf6 suppresses Myc-induced lymphomagenesis [ChIP-seq]
| PRJNA785540 | ENA
Project description:Pcgf6 suppresses Myc-induced lymphomagenesis [RNA-seq]
| PRJNA785559 | ENA
Project description:NF-kB suppresses genomic instability in non-Hodgkin lymphomas
| PRJNA130263 | ENA
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.
2024-05-09 | PXD037534 | JPOST Repository
Project description:Constitutive Kras and NF-kB activation is identified as signature alterations in human pancreatic ductal adenocarcinoma (PDAC). Here, we report that pancreas-targeted IKK2/beta inactivation inhibited NF-kB activation and completely suppressed PDAC development. Our findings demonstrated that NF-kB is required for development of pancreatic ductal adenocarcinoma that was initiated by Kras activation.
2012-01-24 | GSE33322 | GEO
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
2013-05-31 | E-GEOD-42559 | biostudies-arrayexpress
Project description:Constitutive Kras and NF-kappaB activation is identified as signature alterations in human pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms of constitutive NF-kappaB activation in KrasG12D-induced PDAC are not yet understood. Here, we report that pancreas-targeted IKK2/beta inactivation inhibited NF-kappaB activation and completely suppressed PDAC development in KrasG12D and KrasG12D;Ink4a/Arf mutant mice, demonstrating a genetic link between IKK2/beta and KrasG12D in PDAC inception. Our findings reveal that KrasG12D-activated AP-1 induces IL-1alpha, which in turn activates NF-kappaB and its target genes IL-1alpha and p62, to initiate IL-1alpha/p62 feedforward loops for inducing and sustaining NF-kappaB activity. Furthermore, IL-1alpha overexpression correlates with Kras mutation, constitutive NF-kappaB activity, and poor survival in PDAC patients. Therefore, our findings establish a pathway linking duel feedforward loops of IL-1alpha/p62 through which IKK2/beta/NF-kappaB is activated by KrasG12D. To study Kras-induced inflammatory responses and to identify differentially expressed genes between the pancreatic tissues of Pdx1-Cre;KrasLSL-G12D and Pdx1-Cre;KrasLSL-G12D;IKK2/betaF/F mice, cDNA microarray analysis was performed.
2012-01-24 | E-GEOD-27478 | biostudies-arrayexpress