Promotion of pancreatic cancer metastasis by mutant p53
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Owen Sansom
PROVIDER: E-GEOD-67358 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
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.
2015-06-25 | E-GEOD-70262 | biostudies-arrayexpress
Project description:Nearly all colorectal cancers have dysregulated Wnt signalling, predominantly through the mutation of the Apc (Adenomatous Polyposis Coli) gene. Therefore it is of vital importance to elucidate the key Wnt target genes in intestinal cells in vivo. We have used a novel inducible cre-lox based murine system (designated ApcFlox) to investigate the consequences of perturbation of Wnt signalling following inactivation of Apc in vivo within 100% of the intestinal epithelium. We have employed microarray analysis at 3 time points within our ApcFlox system (Day 3 prior to the onset of phenotype, day 4 the establishment of the phenotype and day 5 gross phenotype of altered proliferation, differentiation and migration) and from adenomas arising in the ApcMin/+ background allowing us characterise Wnt/beta-catenin target genes based on their expression profiles during different stages of intestinal tumourigenesis. Furthermore, we have employed microarray analysis using livers from our ApcFlox system and have demonstrated that there is very little overlap in the Wnt target genes induced by Apc loss in the liver and the intestine. More importantly, we have been able to determine a novel set of putative Wnt/beta-catenin target genes which are upregulated at both early and late stages of tumourigenesis in the intestine and may represent novel therapeutic targets in colon cancer. Samples were collected from Genetcially modified mice of the genotypes indicated on the sample records. Where appropriate, gene recombination was induced using IP administration of beta-napthoflavone. Cohorts of samples were used to compare the affects of APC loss in the small intestine at three time points (and compared to matched control samples in which the gene was not recombined). Furthermore, these samples were compared to colonic polyps (and normal colon) taken from the Apcmin Mouse.
2015-01-31 | E-GEOD-65461 | biostudies-arrayexpress
Project description:Dysregulated Wnt signalling is seen in approximately 30% of hepatocellular cancers, thus finding pathways downstream of activation of Wnt signalling is key. Using cre lox technology we have deleted the the adenomatous polyposis coli tumour suppressor protein (Apc) within the adult mouse liver and observed a rapid increase in nuclear beta-catenin and C-Myc. This is associated with an induction of proliferation leading to hepatomegally within 4 days of gene deletion. To investigate the downstream pathways responsible for these phenotypes we analysed the impact of inactivating Apc in the context of deficiency of the potentially key effectors beta-catenin and c-Myc. beta-catenin loss rescues both the proliferation and hepatomegally phenotypes following Apc loss. However c-Myc deletion, which rescues the phenotypes of Apc loss in the intestine, had no effect on the phenotypes of Apc loss. The consequences of deregulation the Wnt pathway within the liver are therefore strikingly different to those observed within the intestine, with the vast majority of Wnt targets beta-catenin dependent but c-Myc independent in the liver. Samples were collected from Genetcially modified mice of the genotypes indicated in the characteristics field. Gene recombination was induced using IP administration of beta-napthoflavone. Cohorts of samples were used to compare the affects of APC loss, cMYC loss and combined APC and cMYC loss in the liver (and compared to matched control samples in which the genes were not recombined).
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Project description:Removal of the transcription factor SAP1a member of the Ternary Complex Factor (TCF) group of transcription factors which in conjunction with Serum Response Factor (SRF) has been shown to have a profound effect on positive selection in the thymus. When another TCF Elk1 is knocked out in mice there is no effect on positive selection unless it is on a Sap1a KO background where the phenotype is very severe. We have stimulated isolated double positive T cells (DPs) with anti-CD3 to mimic positive selection and compared basal and stimulated transcription across the four genotypes to discover the downstream targets of Sap1a involved in positive selection. The Affymetrix mouse Chip Mouse430_2 arrays were used to define gene expression profiles in purified DPs with and with out CD3 treatment from 3 mice for each genotype (Wt,SapKO, ElkKO and SAP/Elk double KO)
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Project description:The TP53 transcription factor is frequently mutated at later stages of epithelial cancers, indicating a possible role in their invasion and metastasis. Importantly, in most cases rather than a simple loss of function p53 mutation, point mutations of p53 accumulate at the protein level and may have dominant negative functions. This study analyses gene expression differences between mice harbouring p53 mutation who do and do not develop metastasis.
2015-03-28 | GSE67358 | GEO
Project description:The transcription factor p73, a member of the p53 tumor-suppressor family, regulates cell death and also supports tumorigenesis, though the mechanistic basis for the dichotomous functions is poorly understood. We report here the identification of an alternate transactivation domain (TAD) located at the extreme carboxyl (C)-terminus of TAp73β, a commonly expressed p73 isoform. Mutational disruption of this TAD significantly reduced TAp73β’s transactivation activity, to a level observed when the amino (N)-TAD that is similar to p53’s TAD is mutated. Mutation of both TADs almost completely abolished TAp73β’s transactivation activity. Expression profiling highlighted a unique set of targets involved in extracellular matrix-receptor interaction and focal adhesion to be regulated by the C-TAD, resulting in FAK phosphorylation, distinct from the N-TAD targets that are common to p53 and involved in growth inhibition. Interestingly, the C-TAD targets are also regulated by the oncogenic, amino-terminal deficient DNp73β isoform. Consistently, mutation of C-TAD reduces cellular migration and proliferation. Mechanistically, selective binding of TAp73β to DNAJA1 is required for the transactivation of C-TAD target genes, and silencing DNAJA1 expression abrogated all C-TAD-mediated effects. Taken together, our results provide a mechanistic basis for the dichotomous functions of TAp73 in the regulation cellular growth through its distinct TADs.
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Project description:WAP-Cre:Ptenf/f:p53lox.stop.lox_R270H composite mice were generated by genetic crossing. In these mice, Pten is deleted and a R270H p53 mutation in the DNA binding domain is induced upon expression of Cre recombinase in pregnancy-identified alveolar progenitors. Tumors were characterized by histology, marker analysis, various bioinformatics methods, high-throughput (HTP) FDA-drug screen as well as orthotopic injection to quantify tumor initiating cells (TICs) and tail-vein injection to identify lung-metastasis. Expression data comparing 2 types of Pten-deficient tumors (spindle and poorly differentiated) with other modles of mouse mammary tumors 2 types of Pten deletion plus p53-R270H mutation tumors (spindle and poorly differentiated) was compared with MMTV-Neu, Spindle Pten-p53-deficient tumors, and wild-type mammary gland cells.
2015-12-15 | E-GEOD-75989 | biostudies-arrayexpress
Project description:Mutations in the p53 tumor suppressor gene are the most frequent genetic alteration in cancer and often associated with progression from benign to invasive, metastatic stages. Mutations inactivate tumor suppression by p53 and endow the protein with novel gain-of-function (GOF) activities that actively promote tumor progression, metastasis and therapy resistance. By comparative gene expression profiling of p53-mutated and p53-depleted cancer cells we identified ectonucleoside triphosphate diphosphohydrolase 5 (ENTPD5) as a mutant p53 (mutp53) target gene. A comprehensive pan-cancer analysis revealed a highly significant correlation between GOF p53 mutations and elevated expression of ENTPD5. Mechanistically, regulation of ENTPD5 by mutp53 is mediated by the histone H3 lysine 4 (H3K4) methyltransferase COMPASS complex. ENTPD5 has been shown to function in the endoplasmic reticulum as a UDPase to promote the N-glycosylation and folding of membrane proteins such as growth factor receptors and integrins. We show ENTPD5 to be a mediator of mutp53 GOF activity in clonogenic growth, architectural tissue remodeling, migration, invasion, and lung colonization in an experimental metastasis mouse model. Our study reveals N-glycosylation in the endoplasmic reticulum as a novel mechanism underlying the progression of tumors with mutp53 that could provide new possibilities for treating cancers driven by GOF p53 mutations.
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