Impact of CDK4-deficiency on EM-BM-5-myc driven B-lymphoma
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ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Xianghong Zou
PROVIDER: E-GEOD-21683 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Impact of CDK4-deficiency on Eµ-myc driven B-lymphoma By crossing mating CDK4 Knockout mice with Eµ-myc mice,We found CDK4-deficiency enhances the Eµ-myc induced B-lymphoma.We further to discover the molecular mechanism
2012-12-16 | GSE21683 | GEO
Project description:Background: MYC is a transcription factor encoded by the c-MYC gene (thereafter termed MYC). MYC is key transcription factor involved in many central cellular processes including ribosomal biogenesis. MYC is overexpressed in the majority of human tumours including aggressive B-cell lymphoma especially Burkitt's lymphoma. Although Burkitt's lymphoma is a highlight example for MYC overexpression due to a chromosomal translocation, no global analysis of MYC binding sites by chromatin immunoprecipitation (ChIP) followed by global next generation sequencing (ChIP-Seq) has been conducted so far in Burkitt's lymphoma. Methodology/Principal Findings: ChIP-Seq was performed with a MYC-specific antibody giving rise to 7,054 predicted MYC binding sites after bioinformatics analysis of a total of 19 million sequence reads. In line with previous findings, binding sites accumulate in gene sets known to be involved in the ribosomal biogenesis, histone acetyltransferase and methyltransferase complexes and the cell cycle demonstrating a regulatory role of MYC in these processes. Unexpectedly, MYC binding sites also accumulate in genes typically expressed in mature B-cells. To assess the functional consequences of altered MYC binding, the ChIP-Seq data were supplemented with siRNA mediated knock-downs of MYC in BL cell lines followed by gene expression profiling. Interestingly, amongst others, genes involved in B-cell function were up-regulated in response to MYC silencing. Conclusion/Significance: The 7,054 MYC-binding sites identified by our ChIP-Seq approach greatly extend the knowledge regarding MYC binding in Burkitt's lymphoma and sheds further light on the enormous complexity of the MYC regulatory network. Especially our observation that (i) many B-cell relevant genes are targeted by MYC and (ii) that MYC down-regulation leads to an up-regulation of B-cell genes highlights an interesting aspect of BurkittM-BM-4s lymphoma biology. [ChIP-Seq] Analysis of MYC DNA binding sites by ChiP-Seq in 5 BurkittM-BM-4s lymphoma cell lines (Raji, Ramos, Blue1, BL41, CA46) [mRNA expression profiling] siRNA-mediated knock-down of MYC was done employing the BL cell lines Raji, BL41 and Blue1 in order to detect MYC-driven gene expression changes. For this purpose, the cells were Amaxa-transfected using MYC smart pool siRNA and control siRNA (Thermo Scientific/Dharmacon, Erembodegem, Belgium), respectively.
2011-11-28 | E-GEOD-30726 | biostudies-arrayexpress
Project description:Mantle cell lymphoma (MCL) is a B cell malignancy characterized by a monoclonal proliferation of lymphocytes with co-expression of CD5, CD43 but not CD23. Typical MCL are associated with cyclin D1 overexpression, and blastoid MCL variants are associated with c-myc translocations. We have developed a murine model of MCL-like lymphoma by crossing Cdk4R24C mice with c-myc-3’RR transgenic mice. Cdk4R24C mice is a knock-in strain that express a Cdk4 protein resistant to inhibition by p16INK4a and other INK4 family members. Breeding Cdk4R24C mice with c-myc-3’RR transgenic mice prone to develop aggressive Burkitt lymphoma-like lymphoma leads in c-myc/Cdk4R24C mice to development of clonal blastoid MCL-like lymphoma. A defect of the INK4-Cdk4 checkpoint can participate to lymphomagenesis in conjunction with additional alterations of cell cycle control, a situation which might be reminiscent of the development of human blastoid MCL. B splenocytes from 4 c-myc/Cdk4(R24C) lymphoma mice and 4 wt mice were investigated.
2012-02-01 | E-GEOD-32230 | biostudies-arrayexpress
Project description:Impact of CDK4-deficiency on Eµ-myc driven B-lymphoma
| PRJNA125843 | ENA
Project description:Ezh2 encodes for the catalyc unit of the PRC2 complex. RNAi-mediated suppressing of Ezh2 by two independent shRNAs promotes Em-myc lymphomagenesis in vivo. Microarray were used to explore the trascriptional changes driven by suppression of Ezh2 in Em-myc cells and to identify which programs contribute to promotion of lymphoma formation. RNA was extracted from purified primary lymphoma cells for each shRNAs targeting Ezh2 and from two independent preparations of premalignant Em-myc cells. Mouse Genome 1.0 ST arrays were processed according to the manifacturer`s instructions.
2015-02-01 | E-GEOD-64537 | biostudies-arrayexpress
Project description:Genomic aberrations of Cyclin D1 (CCND1) and CDK4 in neuroblastoma indicate that dysregulation of the G1 entry checkpoint is an important cell cycle aberration in this pediatric tumor. Here we report that analysis of Affymetrix expression data of primary neuroblastic tumors shows an extensive over-expression of Cyclin D1 and CDK4 which correlates with histological subgroups and prognosis respectively. Immunohistochemical analysis demonstrated an over-expression of Cyclin D1 in neuroblasts and a low Cyclin D1 expression in all cell types in ganglioneuroma. This suggests an involvement of G1 regulating genes in neuronal differentiation processes which we further evaluated using RNA interference against Cyclin D1 and its kinase partner CDK4 in several neuroblastoma cell lines. This resulted in pRb pathway inhibition as shown by an almost complete disappearance of CDK4 specific pRb phosphorylation; reduction of E2F transcriptional activity and a decrease of Cyclin A protein levels. The Cyclin D1 and CDK4 knock-down resulted in a significant reduction in cell proliferation, a G1 specific cell cycle arrest and moreover an extensive neuronal differentiation. Affymetrix microarray profiling of siRNA treated cells revealed a shift in expression profile towards a neuronal phenotype. Several new potential downstream players are identified. We conclude that neuroblastoma functionally depend on over-expression of G1 regulating genes to maintain their undifferentiated phenotype. Experiment Overall Design: The Cell line IMR-32 at time point 0 and transiently transfected with siRNA against GFP, Cyclin D1 and CDK4 at time point 48 hours. All experiments are biological triplicates.
2008-10-25 | E-GEOD-8866 | biostudies-arrayexpress
Project description:The Myc-Max heterodimer is a DNA binding protein that regulates expression of a large number of genes. Genome occupancy of Myc-Max is thought to be driven by E-boxes (CACGTG or variants) to which the heterodimer binds in vitro. By analyzing ChIP-Seq datasets, we demonstrated that the positions occupied by Myc-Max across the human genome correlate with the RNA polymerase II (Pol II) transcription machinery better than with E-boxes. Metagene analyses showed that in promoter regions, Myc was uniformly positioned about 100 bp upstream of essentially all promoter proximal paused polymerases with Max about 10 bp upstream of Myc. We re-evaluated the DNA binding properties of full length Myc-Max proteins using electrophoretic mobility shift assays (EMSA) and protein-binding microarrays (PBM). EMSA results demonstrated Myc-Max heterodimers have high affinity for both E-box containing and non-specific DNA. Quantification of the relative affinities of Myc-Max for all possible 8- mers using PBM assays showed that sequences surrounding core 6-mers significantly affect binding. Comparing to the in vitro sequence preferences, Myc-Max genomic occupancy measured by ChIP-Seq was largely, although not completely, independent of sequence specificity. Our results suggest that the transcription machinery and associated promoter accessibility play an important role in genomic occupancy of Myc. Two protein binding microarray (PBM) experiments were performed: one for the heterodimer of the human transcription factors c-Myc and Max, and one for the Max-Max homodimer. Briefly, 4x44K arrays (Agilent Technologies; AmadID 015681) containing the M-bM-^@M-^Xall 10-merM-bM-^@M-^Y universal PBM design were used. Arrays were incubated with a PBS buffer based protein mixture of wither 10nM His-tagged Myc-Max heterodimer or 10nM His-tagged Max-Max homodimer, 2% milk, 200ng/M-BM-5L BSA, 50ng/M-BM-5L Salmon Testes DNA, and 0.02% TX-100. Bound protein was tagged with 10ng/M-BM-5L anti-His antibody conjugated to Alexa 488 (Qiagen; 35310) in PBS with 2% milk. Data were analyzed to obtain fluorescence intensities for all 8mers. The PBM protocol is described in Berger et al., Nature Biotechnology 2006 (PMID 16998473).
2014-09-22 | E-GEOD-58570 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE33474: Tristetraprolin is a tumor suppressor that impairs Myc-induced lymphoma and abolishes the malignant state [bone marrow B cells]. GSE37790: Tristetraprolin is a tumor suppressor that impairs Myc-induced lymphoma and abolishes the malignant state [Lymphoma]. GSE37791: Tristetraprolin is a tumor suppressor that impairs Myc-induced lymphoma and abolishes the malignant state [retrovirally infected ex vivo lymphoma] Refer to individual Series
2012-08-01 | E-GEOD-37792 | biostudies-arrayexpress
Project description:'The REL gene, encoding the NF-κB subunit c-Rel, is frequently amplified in B-cell lymphoma and functions as a tumour promoting transcription factor. Here we report the surprising result that c-rel -/- mice display significantly earlier lymphomagenesis in the c-Myc driven, Eμ-Myc model of B-cell lymphoma. c-Rel loss also led to earlier onset of disease in a separate TCL1-Tg driven lymphoma model. Tumour reimplantation experiments indicated that this is an effect intrinsic to the Eμ-Myc lymphoma cells but, counter-intuitively, c-rel -/- Eμ-Myc lymphoma cells were more sensitive to apoptotic stimuli. To learn more about why loss of c-Rel led to earlier onset of disease, microarray gene expression analysis was performed on B-cells from 4-week old, wild type and c-rel -/- Eμ-Myc mice. Extensive changes in gene expression were not seen at this age but among those transcripts significantly downregulated by the loss of c-Rel was the B-cell tumour suppressor BTB and CNC homology 2 (Bach2). Q-PCR and western blot analysis confirmed loss of Bach2 in c-Rel mutant Eμ-Myc tumours at both 4 weeks and the terminal stages of disease. Moreover Bach2 expression was also downregulated in c-rel -/- TCL1-Tg mice and RelA Thr505Ala mutant Eμ-Myc mice. Analysis of wild type Eμ-Myc mice demonstrated that the population expressing low levels of Bach2 exhibited the earlier onset of lymphoma seen in c-rel-/- mice. Confirming the relevance of these findings to human disease, analysis of ChIP-Seq data revealed that Bach2 is a c-Rel and NF-κB target gene in transformed human B-cells, while treatment of Burkitt''s lymphoma cells with inhibitors of the NF-κB/IKK pathway or deletion of c-Rel or RelA resulted in loss of Bach2 expression. This data reveals a surprising tumour suppressor role for c-Rel in lymphoma development explained by regulation of Bach2 expression, underlining the context dependent complexity of NF-κB signalling in cancer.'
2014-12-31 | E-MTAB-2774 | biostudies-arrayexpress
Project description:Ezh2 encodes for the catalyc unit of the PRC2 complex. RNAi-mediated suppressing of Ezh2 by two independent shRNAs promotes Em-myc lymphomagenesis in vivo. Microarray were used to explore the trascriptional changes driven by suppression of Ezh2 in Em-myc cells and to identify which programs contribute to promotion of lymphoma formation.
2015-02-01 | GSE64537 | GEO