Project description:Signaling trough cytoplasmic or nuclear action of p53 is a major response mechanism to cellular stresses. Here we perform transcriptomics after p53 re-expression on a CRISPR/Cas9 knock out background to reveal a distinct starvation-specific transcriptome response and novel nutrient-dependent p53 target genes.
Project description:The study "Phase I trial of Adoptive T cell Therapy with Activated P53 specific T cells for Treatment of Advanced Colorectal Cancer" is an open label, single arm trial.
Project description:Mouse Embryonic Stem Cells (ESCs) grown in serum-supplemented conditions are characterized by an extremely short G1-phase due to the lack of G1-phase control. Concordantly, the G1-phase-specific P53-P21 pathway is compromised in serum ESCs. Here we provide evidence that P53 is activated upon transition of serum ESCs to their pluripotent ground state using serum-free 2i conditions and modulates G1-phase progression. Our data shows that the elongated G1-phase characteristic of ground state ESCs is dependent on P53. RNA-seq and ChIP-seq analyses reveal that P53 directly regulates the expression of the Retinoblastoma (RB) protein and that the hypo-phosphorylated, active RB protein plays a key role in G1-phase control. Our findings suggest that the P53-P21 pathway is active in ground state 2i ESCs and that its role in the G1-checkpoint is abolished in serum ESCs. Taken together, the data reveals a mechanism by which inactivation of P53 can lead to loss of RB and uncontrolled cell proliferation.
Project description:Mouse Embryonic Stem Cells (ESCs) grown in serum-supplemented conditions are characterized by an extremely short G1-phase due to the lack of G1-phase control. Concordantly, the G1-phase-specific P53-P21 pathway is compromised in serum ESCs. Here we provide evidence that P53 is activated upon transition of serum ESCs to their pluripotent ground state using serum-free 2i conditions and modulates G1-phase progression. Our data shows that the elongated G1-phase characteristic of ground state ESCs is dependent on P53. RNA-seq and ChIP-seq analyses reveal that P53 directly regulates the expression of the Retinoblastoma (RB) protein and that the hypo-phosphorylated, active RB protein plays a key role in G1-phase control. Our findings suggest that the P53-P21 pathway is active in ground state 2i ESCs and that its role in the G1-checkpoint is abolished in serum ESCs. Taken together, the data reveals a mechanism by which inactivation of P53 can lead to loss of RB and uncontrolled cell proliferation.
Project description:The role of p53 in assuring longevity through prevention of cancer is well established, but how it specifically regulates aging is still controversial. Our assumption is that distinct p53-pathways regulate tumor suppression and aging and that p66Shc is one of the master regulators of the p53 aging function. p66Shc longevity determinant protein acts as a downstream target of p53 and it is indispensable for the ability of activated p53 to induce elevation of intracellular oxidants and apoptosis. We used microarray to gain insight into the mechanism of the physiological activation of p53-p66Shc pathway Total RNA was extracted from freshly isolated thymus, liver, heart and lung of two months old mice (pool of four mice for each genotype)
Project description:The role of p53 in assuring longevity through prevention of cancer is well established, but how it specifically regulates aging is still controversial. Our assumption is that distinct p53-pathways regulate tumor suppression and aging and that p66Shc is one of the master regulators of the p53 aging function. p66Shc longevity determinant protein acts as a downstream target of p53 and it is indispensable for the ability of activated p53 to induce elevation of intracellular oxidants and apoptosis. We used microarray to gain insight into the mechanism of the physiological activation of p53-p66Shc pathway
Project description:Mouse primordial germ cells (PGCs) erase global DNA methylation (5mC) as part of the comprehensive epigenetic reprogramming that occurs during PGC development. 5mC plays an important role in maintaining stable gene silencing and repression of transposable elements (TE) but it is not clear how the extensive loss of DNA methylation impacts on gene expression and TE repression in developing PGCs. Using a novel epigenetic disruption and recovery screen and genetic analyses, we identified a core set of germline-specific genes that are dependent exclusively on promoter DNA methylation for initiation and maintenance of developmental silencing. These gene promoters appear to possess a specialised chromatin environment that does not acquire any of the repressive H3K27me3, H3K9me2, H3K9me3 or H4K20me3 histone modifications when silenced by DNA methylation. Intriguingly, this methylation-dependent subset is highly enriched in genes with roles in suppressing TE activity in germ cells. We show that the mechanism for developmental regulation of the germline genome-defence genes involves DNMT3B-dependent de novo DNA methylation. These genes are then activated by lineage-specific promoter demethylation during distinct global epigenetic reprogramming events in migratory (~E8.5) and post-migratory (E10.5-E11.5) PGCs. We propose that genes involved in genome defence are developmentally regulated exclusively by promoter DNA methylation as a sensory mechanism that is coupled to the potential for TE activation during global 5mC erasure, thereby acting as a failsafe to ensure TE suppression and maintain genomic integrity in the germline. Total RNA isolated from control p53-/- or sample Dnmt1-/- (p53-/-) mouse embryonic fibroblasts
Project description:BACKGROUND: p53 is an important tumor suppressor with a known role in the later stages of colorectal cancer, but its relevance to the early stages of neoplastic initiation remains somewhat unclear. Although p53-dependent regulation of Wnt signalling activity is known to occur, the importance of these regulatory mechanisms during the early stages of intestinal neoplasia has not been demonstrated. METHODS: We have conditionally deleted the Adenomatous Polyposis coli gene (Apc) from the adult murine intestine in wild type and p53 deficient environments and subsequently compared the phenotype and transcriptome profiles in both genotypes. RESULTS: Expression of p53 was shown to be elevated following the conditional deletion of Apc in the adult small intestine. Furthermore, p53 status was shown to impact on the transcription profile observed following Apc loss. A number of key Wnt pathway components and targets were altered in the p53 deficient environment. However, the aberrant phenotype observed following loss of Apc (rapid nuclear localisation of beta-catenin, increased levels of DNA damage, nuclear atypia, perturbed cell death, proliferation, differentiation and migration) was not significantly altered by the absence of p53. CONCLUSION: p53 related feedback mechanisms regulating Wnt signalling activity are present in the intestine, and become activated following loss of Apc. However, the physiological Wnt pathway regulation by p53 appears to be overwhelmed by Apc loss and consequently the activity of these regulatory mechanisms is not sufficient to modulate the immediate phenotypes seen following Apc loss. Thus we are able to provide an explanation to the apparent contradiction that, despite having a Wnt regulatory capacity, p53 loss is not associated with early lesion development. Samples were collected from genetically modified mice. Gene recombination was induced using IP administration of beta-napthoflavone.
Project description:The role of p53 in assuring longevity through prevention of cancer is well established, but how it specifically regulates aging is still controversial. Our assumption is that distinct p53-pathways regulate tumor suppression and aging and that p66Shc is one of the master regulators of the p53 aging function. p66Shc longevity determinant protein acts as a downstream target of p53 and it is indispensable for the ability of activated p53 to induce elevation of intracellular oxidants and apoptosis. We used microarray to gain insight into the mechanism through which p66Shc could regulate p53 oxidative stress dependent activity.