Targeting the Mdm2 oncoprotein by drugs has the potential of re-establishing p53 function and tumor suppression. However, Mdm2-antagonizing drug candidates, e. g. Nutlin-3a, often fail to abolish cancer cell growth sustainably. To overcome these limitations, we inhibited Mdm2 and simultaneously a second negative regulator of p53, the phosphatase Wip1/PPM1D. When combining Nutlin-3a with the Wip1 inhibitor GSK2830371 in the treatment of p53-proficient but not p53-deficient cells, we observed enhanced phosphorylation (Ser 15) and acetylation (Lys 382) of p53, increased expression of p53 target gene products, and synergistic inhibition of cell proliferation. Surprisingly, when testing the two compounds individually, largely distinct sets of genes were induced, as revealed by deep sequencing analysis of RNA. In contrast, the combination of both drugs led to an expression signature that largely comprised that of Nutlin-3a alone. Moreover, the combination of drugs, or the combination of Nutlin-3a with Wip1-depletion by siRNA, activated p53-responsive genes to a greater extent than either of the compounds alone. Simultaneous inhibition of Mdm2 and Wip1 enhanced cell senescence and G2/M accumulation. Taken together, the inhibition of Wip1 might fortify p53-mediated tumor suppression by Mdm2 antagonists. Overall design: Expression profiling by high throughput sequencing
Cooperation of Nutlin-3a and a Wip1 inhibitor to induce p53 activity.
Specimen part, Treatment, Subject
View Samplesp53 induces cell death upon DNA damage, but this may not confer all of its tumor suppressor activity. We report that p53 activation enhances the processivity of DNA replication, as monitored by multi-label fiber assays, whereas removal of p53 reduces fork progression. This was observed in tumor-derived U2OS cells, but also in murine embryonic fibroblasts with heterozygous or homozygous p53 deletion, and in freshly isolated thymocytes from mice with differential p53 status. Mdm2, a p53-inducible gene product, similarly supported DNA replication even in p53-deficient cells, suggesting that sustained Mdm2-expression is at least one of the mechanisms allowing p53 to prevent replicative stress. Thus, p53 helps to protect the genome during S phase, by preventing the occurrence of stalled or collapsed replication forks. These results expand p53’s tumor-suppressive functions, adding to the ex-post model (elimination of damaged cells) an ex-ante activity, i.e. the prevention of DNA damage during replication. Overall design: Expression profiling by high throughput sequencing
p53 Activity Results in DNA Replication Fork Processivity.
Specimen part, Cell line, Subject
View SamplesThe Mdm2 oncoprotein ubiquitinates and antagonizes p53 but may also carry out p53-independent functions. Here we report that Mdm2 is required for the efficient generation of induced pluripotent stem cells (iPSCs) from murine embryonic fibroblasts, in the absence of p53. Similarly, Mdm2 depletion in the context of p53 deficiency also promoted the differentiation of human mesenchymal stem cells and diminished clonogenic survival of cancer cells. Most of the Mdm2-controlled genes also responded to the inactivation of the Polycomb Repressor Complex 2 (PRC2) and its catalytic component EZH2. Mdm2 physically associated with EZH2 on chromatin, enhancing the trimethylation of Histone 3 at lysine 27 and the ubiquitination of Histone 2A at lysine 119 (H2AK119) at its target genes. Removing Mdm2 simultaneously with the H2AK119 E3 ligase Ring1B/RNF2 further induced these genes and synthetically arrested cell proliferation. In conclusion, Mdm2 supports the Polycomb-mediated repression of lineage specific genes independent of p53. Overall design: Expression profiling by high throughput sequencing of p53 ko MEFs, p53Mdm2 ko MEFs, p53ko Mdm2 C462A ki MEFs.
MDM2 Associates with Polycomb Repressor Complex 2 and Enhances Stemness-Promoting Chromatin Modifications Independent of p53.
Specimen part, Cell line, Subject
View SamplesComparative RNA seq analysis of WT and global p73KO Mouse Tracheal Epithelial Cell (MTECs) during the course of their differentiation (Air-Liquid Interface ALI D0, D4, D7, D14) aimed to determine the role of p73 in motile multiciliogenesis. Overall design: Three independent biological replicates of murine primary airway epithelial cell cultures (MTECs) from wild type and global p73KO mice were differentiated under air-liquid interface (ALI) conditions and harvested at Day 0, Day 4 , Day 7 and Day 14 post ALI.
TAp73 is a central transcriptional regulator of airway multiciliogenesis.
Specimen part, Treatment, Subject
View SamplesSpinal cord injury leads to impaired motor and sensory functions. After spinal cord injury there is a an initial phase of hypo-reflexia followed by a developing hyper-reflexia, often termed spasticity. Previous studies have suggested a relationship between the reappearence of plateau potentials in motor neurons and the development of spasticity after spinalization. To understand the molecular mechanism behind this phenomenon we examined the transcriptional response of the motor neurons after spinal cord injury.
Global gene expression analysis of rodent motor neurons following spinal cord injury associates molecular mechanisms with development of postinjury spasticity.
Sex
View SamplesSpinal cord injury leads to impaired motor and sensory functions. After spinal cord injury there is a an initial phase of hypo-reflexia followed by a developing hyper-reflexia, often termed spasticity. Previous studies have suggested a relationship between the reappearence of plateau potentials in motor neurons and the development of spasticity after spinalizaion. To understand the moleclar mechanism behind this pheneomona we examined the transcriptional response of the motor neurons after spinal cord injury as it progress over time.
Transcriptional regulation of gene expression clusters in motor neurons following spinal cord injury.
Sex, Specimen part
View SamplesWe isolated and selected intestinal adenoma organoids from Apcmin/+; Rosa26LSL-TdTomato; Prox1-CreERT2 mice. After the selection procedure without growth factors, we induced CreERT2 activity and the transcription of tdTomato to label Prox1+ cells by 300 nM 4-hydroxytamoxifen for 16h. tdTomato+ (Prox1+) and tdTomato- cells (enriched for Prox1- cells) were FACS sorted and total RNA was isolated.
Transcription Factor PROX1 Suppresses Notch Pathway Activation via the Nucleosome Remodeling and Deacetylase Complex in Colorectal Cancer Stem-like Cells.
Specimen part
View SamplesKrppel-like factor 3 (KLF3) is a transcriptional repressor that has roles in adipogenesis, B-cell maturation and erythropoiesis (for review see Pearson et al., 2012).
Regions outside the DNA-binding domain are critical for proper in vivo specificity of an archetypal zinc finger transcription factor.
Specimen part
View SamplesMammalian epidermal stem cells maintain homeostasis of skin epidermis and contribute to its regeneration throughout adult life. While two-dimensional mouse epidermal stem cell cultures have been established decades ago, a long-term, feeder cell- and serum-free culture system recapitulating murine epidermal architecture has not been available. Here we describe an epidermal organoid culture system that allows long-term, genetically stable expansion of adult epidermal stem cells. Our epidermal expansion media combines atypically high calcium concentrations, activation of cyclic AMP, FGF and R-spondin signaling with inhibition of BMP signaling. Organoids are established robustly from adult mouse skin and expand over at least 6 months, while maintaining the basal-apical organization of the mouse interfollicular epidermis. The system represents a powerful tool to study epidermal homeostasis and disease in vitro. Overall design: We establish an organoid culture system for long-term expansion of mouse epidermal stem cells. Using histological methods as well as low-coverage multiplexed RNA sequencing, we show that cultured organoids resembled interfollicular epidermis. We analyzed a total of 23 samples, including 6 controls that are isolated from the skin of mice. None-passaged as well as cultured organoids were compared with replicates. Differences growth factors and small molecules that allow expansion of organoids were compared with replicates.
Long-term expansion and differentiation of adult murine epidermal stem cells in 3D organoid cultures.
Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A global DNA methylation and gene expression analysis of early human B-cell development reveals a demethylation signature and transcription factor network.
Specimen part
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