Subtle variations in Pten dose determine cancer susceptibility: Gene expression profiling of a Ptenhy/+ mouse model
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE20316 | GEO | 2010/02/15
SECONDARY ACCESSION(S): PRJNA125491
REPOSITORIES: GEO
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Project description:Subtle variations in Pten dose determine cancer susceptibility: Gene expression profiling for MEF cells from a Ptenhy/+ mouse model. We have analyzed the survival and tumor spectrum in a population of Pten âhypermorphicâ mice (Ptenhy/+), which express approximately 80% of total Pten protein. Notably, the Ptenhy/+ developed a spectrum of tumors of variable latencies, with breast tumors occurring at the highest penetrance. Surprisingly, all breast tumors analyzed retain two intact copies of Pten, and maintain Pten protein levels above that observed in heterozygosity. Importantly, subtle down-regulation of Pten was found to alter the expression profile of genes involved in cell proliferation. Taken together, our findings support the notion that initiation of tumorigenesis can occur in the absence of genetic hits, thereby questioning the uniqueness of a saltatory model for cancer susceptibility. In order to understand whether subtle variations in Pten level may affect pathways involved in tumorigenesis, we analyzed the genome-wide expression profile of Ptenhy/+ mouse embryonic fibroblasts (MEFs). In the Ptenhy/+ mouse model, mice are born with approximately 80% of total Pten protein and are viable and normally fertile. To decrease the expression level of Pten below homozygosity, we targeted intron 3 of Pten with a neomycin (Neo) cassette, under the control of the strong CMV promoter, thereby taking advantage of transcriptional interference. Next, we intercrossed Pten hy/+ mice with Pten+/- mice to generate cohorts of hypomorphic littermate mice with decreasing levels of Pten expression as follows: Ptenwt > Ptenhy/+ > Pten+/- >Ptenhy/- mice littermates. To preserve a constant 129/C57BL/6 mixed genetic background, we have crossed Pten hy/+ mice with Pten +/- for more than seven generations prior to analysis. As expected, Ptenhy/+ mouse embryonic fibroblasts (MEFs) display a level of Pten protein below Ptenwt and above Pten+/- .
2010-02-21 | E-GEOD-20316 | biostudies-arrayexpress
Project description:Subtle variations in Pten dose determine cancer susceptibility: Gene expression profiling of a Ptenhy/+ mouse model
| PRJNA125491 | ENA
Project description:Trangenic mice with brain-targeted deletion of one allele of p53 and one allele ot Pten were irradiated with particulate radiation. Radiation induced gliomas were analyzed to identify copy number variations
2019-07-01 | GSE130677 | GEO
Project description:Pituicytoma (PITUI), granular cell tumor (GCT), and spindle cell oncocytoma (SCO) are rare tumors of the posterior pituitary lobe. Histologically, they may be challenging to distinguish and have been proposed to represent a histological spectrum of a single entity. We performed targeted next-generation sequencing, DNA methylation profiling, and copy number analysis on 47 tumors (14 PITUI; 12 GCT; 21 SCO) to investigate molecular features and explore possibilities of clinically meaningful tumor subclassification. We detected two main epigenomic subgroups by unsupervised clustering of DNA methylation data, though the overall methylation differences were subtle. The largest group (n=23) contained most PITUIs and a subset of SCOs and was enriched for pathogenic mutations within genes in the MAPK/PI3K pathways (12/17 [71%] of sequenced tumors: FGFR1 (3), HRAS (3), BRAF (2), NF1 (2), CBL (1), MAP2K2 (1), PTEN (1)) and two with TERT promoter mutation. The second group (n=16) contained most GCTs and a subset of SCOs, which mostly lacked identifiable genetic drivers. Outcome analysis demonstrated that the presence of chromosomal imbalances is significantly associated with reduced progression-free survival especially within the combined PITUI and SCO group (p= 0.031). In summary, we observed only subtle DNA methylation differences between posterior pituitary tumors, indicating that these tumors may be best classified as subtypes of a single entity. Nevertheless, our data indicate differences in mutation patterns and clinical outcome. For a clinically meaningful subclassification, we propose a combined histo-molecular approach into three subtypes: One subtype is defined by granular cell histology, has low mutation rates and favorable outcome. The other two subtypes have SCO or PITUI histology but are separated by chromosomal copy number profile into a favorable group (no copy number changes) and a less favorable group (copy number imbalances present). Both of the latter groups have recurrent MAPK alterations that represent potential therapeutic targets.
2021-10-19 | GSE185041 | GEO
Project description:Inactivation of Pten occurs by multiple mechanisms including epigenetic silencing, point mutations, insertion, and deletion, which are tissue dependent. Although frequent loss of heterozygosity around Pten locus and plausible involvement of epigenetic silencing have been reported in radiation-induced thymic lymphomas, the frequency of Pten inactivation and the spectrum of causal aberrations have not yet been extensively characterized. Here, we assessed the principal mode of inactivation by comprehensively analyzing expression and alterations of Pten gene in 23 radiation-induced thymic lymphomas developed in B6C3F1 mice. We found no evidence for methylation-associated silencing of Pten gene. Instead, we found complex structural abnormalities in 8 lymphomas (35%) that included missense and nonsense mutations, 1- and 3-bp insertions, and focal deletions. Sequencing of deletion breakpoints suggested that illegitimate V(D)J recombination and microhomology-mediated rearrangement were responsible for the focal deletions. Seven out of these 8 lymphomas had biallelic alterations, and 4 of them did not express any Pten protein. These aberrations of Pten were well coincided with downstream Akt phosphorylation on Ser473. In conclusion, Pten inactivation, which is frequently biallelic and is caused by a variety of structural abnormalities but not by epigenetic silencing, is involved in radiation-induced lymphomagenesis. Three thymic lymphomas were analyzed by array-CGH method.
2010-05-06 | E-GEOD-17751 | biostudies-arrayexpress
Project description:Mutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain. Gene expression of 8 human brain samples including 2 normal brainstem and 6 brainstem low-grade gliomas were profiled using HG-U133 plus 2 arrays. Gene expression of 38 mouse tumor samples, including 24 Pten;p53 double knockout and 14 Pten;p53;Rb1 triple knockout, were profiled using Affymetrix Mouse Genome 430 v2 arrays. Copy number changes of 51 double knockout tumor samples were analysed using Roswell Park Cancer Institute 6.5k BAC arrays. Copy number changes of 21 triple knockout tumor samples were analysed using Agilent mouse genome CGH mocirarray 244A.
2011-03-23 | E-GEOD-22927 | biostudies-arrayexpress
Project description:Phosphatase and tensin homolog (PTEN) is a tumour suppressor gene associated with inherited tumour susceptibility conditions, macrocephaly, autism, ataxia, tremor and epilepsy. Functional implications of this protein have been investigated in Parkinson’s and Alzheimer’s diseases. We describe the first patient presented with multifocal demyelinating motor neuropathy in association with a de novo PTEN mutation. The pathogenicity of the mutation was supported by altered expression of several proteins involved in tumorigenesis and fibroblasts showed a reversible defect in catalytic activity of PTEN against the secondary substrate, phosphatidylinositol 3,4,-trisphosphate, suggesting a novel and potentially treatable mechanism for multi-focal demyelinating motor neuropathy.
2018-10-22 | PXD008014 | Pride
Project description:Mutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain.
2011-03-23 | GSE22927 | GEO
Project description:PTEN is thought to play a critical role in T cell activation by negatively regulating the PI3K signaling pathway important for cellular activation, growth, and proliferation. T cells from mice in which PTEN was conditionally deleted in the thymus were reported to display CD28-independent IL-2 production and relative resistance to anergy induction. However, such observations could have stemmed from alterations in T cell development due to early deletion in thymocytes. To directly eliminate PTEN in post-thymic T cells, we utilized CAR Tg x PTENflox/flox mice which enabled gene deletion using a Cre adenovirus in vitro. Gene expression profiling revealed a small subset of induced genes that were augmented upon PTEN deletion and T cell stimulation. Our results indicate that deletion of PTEN can augment the activation of post-thymic T cells. Nonetheless, PTEN inhibition may be a viable target for immune potentiation due to increased cytokine production by activated CD4+ cells. It was of interest to determine the spectrum of transcripts regulated by PTEN using gene expression profiling. To this end, CAR Tg x PTENflox/flox Th1 clones were either treated with adeno-Cre or adeno-EV, then confirmed to have PTEN protein abscence by western blot, then stimulated for 6 hours with anti-CD3/anti-CD28 mAb- coated beads and analyzed (2 total conditions). The experiment was replicated so there are 2 samples for each condition.
2013-02-01 | E-GEOD-43936 | biostudies-arrayexpress
Project description:Recent publications have described an important role for cross talk between PI-3 kinase and sonic hedgehog signaling pathways in the pathogenesis of medulloblastoma. Our primary objective was to determine if loss of Pten promotes medulloblastoma tumor formation. When mice expressing SmoA1 were crossed with mice heterozygous for Pten, SmoA1 +; Pten +/- mice exhibited decreased survival, an increased incidence, and a shorter time to onset of symptoms, compared to SmoA1 +; Pten +/+ mice. Tumors from SmoA1 +; Pten +/+ mice exhibited classic histology. In contrast, tumors from SmoA1 +; Pten +/- mice exhibited predominantly nodular/desmoplastic histology and evidence of neuronal differentiation. Analysis by gene expression microarray revealed a clear separation of gene signatures, with upregulation of genes such as Pik3cb, Mapk8, Frap1, and multiple genes involved in angiogenesis in SmoA1+; Pten +/- tumors. Downregulated genes included Pten, Trp53, and Rb1. Western blotting and immunohistochemical analysis revealed decreased expression of Pten and increased activation of Akt in the SmoA1+; Pten +/- tumors. Consistent with these findings, we detected strong expression of PCNA throughout the Pten +/+ tumors and focal areas of intense staining for PCNA in tumors from SmoA1 +/-; Pten +/- mice. Conversely, staining for Cleaved Caspase 3 revealed multiple punctuate foci in SmoA1 +; Pten +/+ tumors and almost no staining in SmoA1 +/-; Pten +/- tumors. These results suggest that increased signaling through PI-3 kinase pathways promotes MB tumorigenesis by driving proliferation and inhibiting apoptosis of granule neuron precursor cells in the developing cerebellum.
2009-11-21 | GSE19059 | GEO